Most port designs take advantage of what is called "helmholtz resonance", much like what produces the sound in a pipe organ. By tuning the port/box/woofer combination, one can use this phenomena to produce bass notes at lower frequency and higher spl than the woofer could in a sealed box at the cost of (usually) a larger box. At least that's how I understand it.
Can we say that a studio monitors with ports gives us different bass frequencies than are actually recorded?... so treating the room or blocking the port does similar things... I use the monitors very quietly because of neighbours, so will blocking the ports take my room out of the equation?... thank you :)
G.day brother what would u recommend in my case.I want to build a low mids box for my car audio use if 6 12” should I build a ported or seal box plz note that the boxes will be facing outwards back the back door window
Intuition tells me placement is even more important for rear ported speakers as they are "playing the room" more (back wall reflections). Same for dipoles, magnetic planar, electrostatic, open baffle, etc. True or false?
Every programming language has bit-shift operators. Although it's generally true that you can only take advantage of the carry bit and use circular shifts in machine language - unless the compiler is intelligent and can understand that sequences like this can be implemented with a circular-shift instruction: #define MSB_MASK 0x80000000; int Cbit, shiftreg; Cbit = shiftreg & MSB_MASK; shiftreg
The pressure inside a ported box is actually higher than a sealed. Low frequency waves actually go through the box a whole lot easier (below the tuning frequency of the enclosure, Fb.), this is called unloading. Below Fb the speaker increasingly "sees" no enclosure at all and will rolloff at ~24dB/octave. To avoid damage to a vented box with somewhat high Fb you need to highpass the frequencies below Fb as these will cause excessive excursion to the driver. Port "chuffing" can be largely avoided by simply decrease its air velocity to below 17m/s. Many use flanged ends to help alleviate this problem as well. A well designed port/enclosure will won't have these issues to any audible degree. A T/L and vented enclosure is not the same thing. Front port or rear ports really does not matter at all in a technical perspective. The wavelengths at low frequencies are so long that the port placement only amounts to a fraction of a frequency cycle's phase difference. You must have some distance (normally at least the vents diameter) between the wall and the backside of the enclosure which can lead to issues if you try to hang it on a wall or something. The main reason they place the vent at the back is to be able to save space really. Futhermore, a vented enclosure is by itself more efficient and has lower non-linear distortion than a sealed enclosure due to less excursion around Fb. This of course increases the maximum output of the driver within its voice coil thermal ratings. The only thing that a sealed enclosure is better at: as mentioned, the actual group delay/phase shift. The vent cause a phase shift in its passband which increases its group delay in these frequencies. This group delay's audibility must be seen in relation to the actual frequency. At 50Hz a full period is 20ms (1/50=.02s), while at 25Hz a full period is 40ms (1/25=.04s). With certain alignments the group delay can exceed a full period, at some point it starts to get noticable and this is what people refer to as "sloppy bass". A lot of times this issue is fixed by simply equalizing the frequency response as group delay is a derived function of the magnitude and phase response. The enclosure-inherited group delay of a vented design can be fully corrected for with FIR-based signal processing. In my opinion, the vented enclosure is usually far superior to a sealed box, especially if you got a powerful DSP / room correction. Note that not all drivers are suitable to use in vented enclosures, most high Q-drivers should be avoided for example.
I love your expert opinion on amplification but your explanation on ported speakers is flat wrong. #1 the sound coming out of the port is in phase with the woofer whether front or rear ported. #2 The port is not a pressure release (in the frequencies in which it performs it's duties). #3 A port does not work like a transmission line to invert the phase. A port tunes the box at a certain frequency determined by the diameter and length of the port. At this tuning frequency, the woofer and port output are in phase. Because the woofer is moving in the same direction as the air in the port, the pressure inside the enclosure is GREATER than the pressure of a not ported(sealed enclosure). Don't believe it? Run this test. Find the tuning frequency of the ported speaker by running an impedance sweep. There will be 2 humps in the low frequency area. In between the 2 humps will be a valley, this is the frequency at which the ported speaker is tuned. Let's say the impedance dips between the 2 humps down to 6 ohms at 40 hz. Plugging the port with your hand, run a 40 hz test tone through the speaker until you see the woofer really moving. Now take your hand off the port and notice that the woofer now is barely moving yet the speaker is producing even more bass. The reason is, the air spring (pressure) in the box has increased due to the port output being in phase with the woofer.
Ports box is more produced Louder bass than sealed box but there is delay bass frequency comes out. Sealed box is always had smaller box needed and more accurate bass than port bass
I've recently been doing plenty of experimentation with ported box designs, including making my own 6th order bandpass box, and here is what I've learned about how ports behave. They are in fact in phase with the diaphragm, due to their resonance their phase is inverted, causing them to add to the air displaced. If they subtracted, there should be an output dip either side. This also causes an impedance dip, as the pressure within the box, experiences a peak caused by the added displacement. The driver moves slightly less due to the pressure, and causes an impedance dip as EMF decreases voltage being fed back to the amplifier. Efficiency is increased as power is "shifted" from moving a diaphragm with relatively high mass to a tube of air resonating, with a relatively low moving mass. Ported boxes have a steeper roll-off than sealed, as the port doesn't allow pressure to build up lower than its resonance. Low frequency air flow may come and go as it likes. It behaves sealed at higher frequencies, however only reflected waves come through. Due to bass having an inherent non-directionality associated with its creation, the speaker box is simply adding or subtracting the local air pressure around it. Phase from front to back shouldn't matter. Enclosures where it does are referred to as "dipoles". Port surface area is relative to length for tuning, possibly why front ported boxes have longer ports is due to a greater surface area attempting to eliminate "chuffing" with lower velocity airflow. As far as I'm aware passive radiators behave like ports, though without chuffing, are less efficient, and from what I can tell work better with smaller boxes than ports. Transmission line speaker enclosures work by having a set transmission line length, usually tuned to either 1/4 or 1/2 wavelength of the desired tuning frequency, feed the rear wave down a tube with said resonance. Port width is usually equal to the driver surface area and constant along the line, unless a tapering/horn loaded design is used. The effect on the air from thought experiments is like hanging a weight from a bungee cord, move your hand at the resonance of the weight, and although your hand is moving only a 1/4", the weight may be moving 1" or more. This works similarly to a ported box, though requires much more space. Generally transmission line boxes reach the lowest notes, though this may be due to them performing as dipole enclosures down low. Dipole enclosures (also from thought experiments) effectively add a springy moving mass to the driver, lowering its resonance, which improves low end. The distance between the front of the driver and the rear creates the pressure differential, and therefore sound. I kinda fell half asleep whilst writing this, so hopefully it makes sense
"They are in fact in phase with the diaphragm, due to their resonance their phase is inverted, causing them to add to the air displaced." This is not true. At the precise resonant frequency, resonators respond IN PHASE to the driving function. Thus port emissions exactly at their resonant frequency will tend to cancel the woofer front wave and produce a narrow dip (notch) in the response. Resonant systems exhibit a large shift in phase response, comparing at frequencies just below and just above resonance. Ultimately, an undamped system can exhibit nearly +/- 90 deg. phase shifts across a narrow frequency range. In the region below resonance, the port can add boost to the woofer, but at or above resonance it tends to partly cancel the woofer front wave. If you do careful response measurements at small frequency steps for a ported speaker system, you may find significantly uneven results.
Actually the port sound output is in phase in its adjusted frequency. Due to resonance of the enclosure and the "Piston mass" inside the tube. Lets say you want to adjust the bass reflex supporting frequency to 35 Hz. You got a 50 L Box, than you need a round port approx 4" width times 12" length. Big floor standing speaker. Out of the adjusted frequency the "Air Piston" in the tube can not move properly, or even not at all. The fuction of the port increased if approaching the frequ. and its decreasing if leaving. But in this case it doesnt matter in my eyes, if the port is in the front or in the back. Because the wave length at 35 Hz is 10 yarts and you got a 1' deep Speaker maybe (front to back). So the back port would be 1/30th out of phase reaching your ears. Bass is emitting nearly 360° the same around the speaker. so doesnt batter to me. A passive Butterworth Frequency cross over for example, with -6 db per octave, generates a 90° delay in Phase in the low pass way, thats nearly 4' - Bass/Mid separation at 300 Hz . However it is the commonest frequency cross over. That tears apart the exact imaging of the stage arround the crossing frequencies. Some very smart invetors and developers build speakers that wave no delay in Phase, absolutely time coherent. A giant step towards natural sound play back. cheers.
Jean Katana Above the the tuned frequency the air mass within the port cannot move freely, but below it, it can. This is one of the caveats of ported loudspeakers, below the tuning frequency, of the port, the cabinet and port offer no control over the motion of the cone. The driver unloads, excursion shoots up with falling frequency, and the output rapidly reduces.
5:45 this is incorrect. Vents do not relieve pressure inside the box, on the contrary it increases the pressure until you get to a little below the fb. Air has mass and the ports use this mass to load the driver. Push a lot of air through a little hole and it moves very quickly, when the driver begins moving back the other direction the air in the port is still moving the same direction this is where the increased pressure comes from and why you get more sound pressure. Sound is pressure, less pressure less sound.
Odd that such a seasoned audio professional would make such a glaring error. Hmmm. I listened to it a couple times and that's what he said. Misspoke, or actually doesn't understand fundamental physics of mass and momentum?
Nope if a box is designed to be ported then it can't be sealed as the enclosure dimensions are calculated by the driver specifications . So if you want a seal enclosure then you have to calculate according to the drive specifications .
brian weir my Focal tower TL speakers have a front port. So do my old college airborne/phillips set. my B&W's have a rear one, and my Infinitys don't . All those great folks who designed them were not hacks; similar to your comment on A vs D, I think the original design and intent is the most important thing. They are all different and likeable to me. I like my Focals best in general. 1 second ago
brian weir I too have a pair of transmission line speakers with Focal drivers and I absolutely love them! I designed and built them myself with a great deal of care and effort. I have designed and built a number of ported designs and a few sealed designs but none came close to the sound of the TL’s. To me TL’s seems to have this effortless quality to them. They sound more open and dynamic (sort of like comparing open back dynamic headphones to closed pressure style I guess).
Every port shifts the phase by 90 degrees at its tuning frequency, no matter on which side of the enclosure it sits. If it's on the back you usually lose a few decibels in the bass because the phase shift increases due to the time it takes the sound to travel from the back to the front. Wave lengths in bass are big in comparison to the dimension of the enclosure therefore they bend around the edges (spherical radiation). But ports also let a small amount of mids pass through which is perceived as distortion. In the mids the sound waves are smaller and don't bend around the edges. Therefore they don't reach the listerner if the port of a mid-woofer is on the back. With a port on the front this distortion might lessen the sound quality. The solution: port on sides, top or bottom as near to the front as possible. The huffing and puffing noises are generated by turbulences of the air flow inside the port and on its edges. Therefore those Elac speakers have a port with round edges. If the diameter of the port is too small the air flow gets too fast and turbulences occur even on the surface of the inner wall of the tube. The cross section of the port should be at least one fifth of the effective piston area of the driver. Even better is one fourth or more but the length then might become too big for the same tuning frequency. The standing wave inside the tube becomes a problem then. Before I discovered your "Ask Paul" series I started a similar podcast in German, apart from most of my other videos being in English. Im currently translating my first few episodes into English but it takes a lot of time because they were not scripted. On many of them RUclips's automatic subtitle function didn't even work. (The German version seems to be not that good yet.) If I gathered some more subscribers from the English speaking world it would maybe motivate me to speed up my work. Source of all my knowledge: German DIY loudspeaker magazine Hobby HiFi.
Methinks Mr. PS audio needs to check out all the studio speaker (4343,4344, 4350 etc.) JBL put out over the years with larger ports 4-6 inchs that sound absolutely fantastic. :>)
I prefer the curve of my ported subs. High at 30hz and steep roll off from 40 to 80 hz. I've spent my life chasing after perfection and to me this is as close as I can get. They lack the punch of a flatter curve, but I'll take that trade off. There is only one song I know of where my setup has an obvious lag between notes and it bothers me but I would still not trade it for anything else, especially not a sealed subwoofer. So much of this has to do with what music you listen to, and I think when people have disagreements they sometimes fail to take that into account.
I can appreciate the use-case scenario. I personally prefer using a bigger amp and more EQing to get a similar curve from a sealed enclosure. I’m sure they’re out there, but I’ve never heard a ported enclosure with good subsonic extension. Ports can create phase issues that can be very difficult to address. Of course, if power limits at a large venue are limiting, a ported enclosure would make sense.
just looked thru some comments ( about 30 + ) didn't see anyone mention ' Thiel / Small' one of if not the first computer type speaker box/ port designs.... My Koss speakers ( 1978 1020 ) Koss claimed were the first to use this development. Seemed to work, the Stereo Review mag , Sept '78 > had a comment ' response curve flat + - 2 from 20 to 5000 hz'.... (closer to an amp than most speakers, even Advents of the day.my thought.) and distortion ' among the lowest we have yet measured' PS the Koss were fairly large, the mid range 1020's 33in high, 15 wide - 10 in bass with 2 front ports. Just as a guess, ported designs seem very common today.
I wish you’d do a comparison of sealed , ported , and passive radiators. I’m personally a fan of how passive radiators sound. But there’s very little information available on them
I prefer sealed over ported, but some ported models are great also. Rear ported designs are much better than front ports, to me anyway. Sealed just has a cleaner smoother bass and just plain sounds better I think.
I have a pair of B&W 804 D3 floor standing speakers. They sit 3 feet from the back wall but are close to the side walls. I didn’t like the mid bass boom I was getting so I have now put the supplied foam bungs in the ports that are on the front of the speakers. They sound way better now. If I add a sub (or two) to extend the bass down, would I still get any bass bloat in the room, seeing as the 804s are now “sealed”? Thanks.
When properly designed and manufactured, ported speakers can be used in two different ways: if you have the room to have your speakers out from the rear wall, as in on stands, rear ported speakers will be your best bet. If you don't have the room, and may even have to wall mount then a front ported design would be your best bet.
Conversely to having a port. Does the sealed speaker with the compression and vacuum going with the cone operation, vacuum when out, pressure when in, actually create a quicker stop and then quicker restore of the cone and reduce vibrations as the cone goes back to its central position. Thus making the base truer to the original as it is now self controlled. Overthrow and sluggish return are now self regulated by the size of the box in relation to the cone movement.
Ports are a way to alter the physics needed of enclosure size to produce sufficient bass. I used to own a few of the Dunlavy speakers that were all sealed boxes - no ports at all. And they had terrific bass, but they were large enclosures (not very high on the wife-acceptance scale). If you didn't mind your speakers almost as large as your refrigerator, the bass was articulate, fast, and very real, with none of the problems with ports. Still the best I've ever owned.
Hi Paul. I have a pair of Roland DM-20 front ported. Because I'm curious I pulled them open and found them empty except for the built in amp. I decided to stuff them a little bit with some pillow material. These are monitor speakers used, and was wondering if filling them is OK? They sound good, especially once I took them off the floor. Should I not have stuffed them, or does it not matter? I use them for listening to music, not mixing or anything. Thanks!
Not to beat a dead horse but I have a set of AAD 2001 monitors , 4.75 inch driver , rear ported . I invite anyone to detect any audible port discharge noise from these Phil Jones marvels. easily 32 hz from a small monitor with a small bass inch driver..... DESIGN ….
And here I thought you were going to speak loudly about Port wine. 😄 Kali Audio purports (NPI) to have solved the port 'chuffing' issue with their front port design. You might look into that if you are curious.
Ports have some specific disadvantages. First of all, the loudspeaker is acoustically unsupported below resonance. The box is open. Any frequency below the box tuning causes excess cone motion. The second major disadvantage is that the box is a Helmholtz resonator that only resonates at one frequency. That adds pressure to the bass, but not at the same frequency. One difference between a port on the front, back, sides, top or bottom is its proximity to the wall which can aid or hurt the amount of pressure. Another difference is if the midrange that leaks out of the hole can be heard by the listener or not.
Front ports, when done right, do allow for greater freedom in speaker positioning. So, they are potentially better than rear ports. Done wrong, they make those wind gusts more audible than rear ports. So, they are also potentially worse than rear ports.🤓
It's been my observation through the years that I prefer rear-firing ports as opposed to front firing port. IDK if the bass slams into the corner of the room behind the speaker and has more wave-length to travel or what. I was skeptical of my Kicker's Sub-box having a huge side aeroport, but it doesn't seem to effect any sound quality. so... IDK.
More in-depth info here: barefacedbass.com/technical-information/the-mysteries-of-ports.htm ...and a 40 min seminar here: facebook.com/BarefacedAudio/videos/10155712331072704/
G.day I’m all the way from Guyana I need to know if I should use a Ported or seal box for my low mids,plz note that the boxes are facing out the car by the back side window
So my question is what is a proper preamp to amplifier to mixer hook up. I write and play music for the love of it. And just want my sound to sound live and clear. But I do have a small room size for my set up. I do share the signal with a home audio receiver.
In a ported design the speaker cone barely moves near the ports tuning frequency. So the box and cone actually see much more pressure than a sealed enclosure. This can have a couple advantages like reduced distortion if designed correctly. This is a misnomer and common misconception that sealed produces less distortion. There are many advantages like the amp is only needing half the power at the same loudness further reducing distortion. If you dont believe me listen to a self powered gelelec studio monitor. No chuffing either .
It is kind of weird, I did a little bit of research the past weeks and I already know what he is saying isn't really correct, he admits he doesn't know much about it, no problem, respect. But considering his business one would expect at least a decent amount of knowledge about the basics of ported speakers. I went to the website, the only speakers I found there where front ported speakers...
ported suits me better for what i listen to, maybe for those rare parties with hip-hop aren't perfect in terms of bassy but for voice and movie sounds it's more nonresonant, someone walking in forest steps on a dry branch - it's he in a forest or a corridor?
You said that only high frequency goes out than you said that bass output goes out too but bass is a low frequency and you said low frequency cannot pass to the vent can someone explain me what im confusing
The port has an air mass that is suspended with the airvolume inside the box. When this mass reach resonance due to the triggered soundpressure from the woofer, it starts to resonate. At resonance, the air in the port goes out when the woofer does. This will enhance the bass level. The wavelength at 50Hz is about 7 meters, so it does not matter if the port is in front or on the rear. However, at lower frequencies than the ports resonance frequency, the air in the port starts gradually to get sucked in while the woofer goes out.
From personal experience... I listen nearfield with the speakers at ear level. When I had front ported speakers? When certain notes were hit, it was like sitting in front of a hair dryer set to cool. On cold nights I would get cold air blown in my face. So... rear ports have another good purpose. I prefer sealed or passive radiator speakers. More accurate sounding.
I recently purchased Kali Audio front ported Studio Monitors. I used to have the Yamaha HS8's, but the 8" woofer with the rear port produced to much boomy bass as my studio is small thus my speakers are forced to be closer to the wall. The front ported Kali Audio monitors with 6.5in woofers and front port design fixed my issues perfectly. In addition they have a trim pot to compensate for speaker locations and room environments. So sometimes front is better depending on the the acoustics of your listening room.
Sealed has a cleaner sound but requires more power. I personally think it depends on what kind of music you listen to. I dont know. I like a sealed box for rock and metal. But if you get into the hip hop style the speaker cant react fast enough and starts to bog. If that makes any sense. Love all your videos Paul.
NTH Welding , I had an old vintage pair of Advent 3 way speakers with a 12 inch woofer, 4 inch mid and 1 1/2 inch dome tweeter, sealed. I compared them to a set of equal speakers made by Cerwin Vega, no comparison, the Vegas blew them away. but on the other hand, the Advents although took more power to run as loud had a much tighter hitting bass frequency, so I just used all four speakers in the same room. the sound was great!!!!! it really comes down to if you have tube amps or digital amps and what type of music you like.
Rear ports are more picky in regards to room placement. If a rear ported speaker is placed too close to a wall, there can be either an increase in bass amplitude or a cancellation of lower frequencies due to reflections and phase alterations of the sound leaving the port. Make more room behind them, and they will have smoother bass characteristics. Front ported speakers do not experience this problem, so they can be placed closer to walls. But because the port is facing the listening space, it might be easier to hear the port noise. I've got some rear ported bookshelf speakers, and they're pretty close to a wall, so I ended up plugging their ports. Their bass sounds muuch less boomy. And the reduced bass range is being taken up by my subwoofer. It's a win-win.
I just bought a pair of made in 2002 Paradigm Mini monitors Ver.2 I have read that years back Paradigm used to supply plugs for the rear ports if needed for placement reasons in a said room. At any rate I believe in your comment greatly. Rear ported speakers can be be more picky on the speaker to wall distances. We will see what happens. They will be here tomorrow and yes already running a pair of Yamaha powered subs so I know for sure I can work something out. Thanks greatly on your comment CaveyMoth.
@@CaveyMoth Supposedly the Mini's Ver.2,, 3's, and 4's are supposed to be all that. I did a ton of digging on these speakers. I have ran 70's, 80's and a few 90's loud speakers all my life. I hope these will be a bit more resolving. Great hearing from you.
Glad to see you're promoting the elac line I have a set of UF5 Towers and the UB5 bookshelves and hoping in the near future to purchase your Sprout 2 for my UB5's great job🎧🎶
Ive got a question for Paul McGowan and viewers out there. I'm building a 2x12" speaker cabinet for a 100w peavey valveking head and wondered should I port the cab? I don't really want too as it will be a closed back cab, but does and will it make a huge difference in the sound if I do? And if I put a small hole in the cab say 10-15 or 20mm for example just to let the speakers breath/move properly within the cab and not let out alot of noise will this help with speaker over all speaker perfomance and or sound? Thanks and love your videos.
What most people seem to forget is that sealed speakers also have a port. That is the driver itself. The driver's backwave will resonate and reflect back through the cone in a number of rather unpredictable ways. And that is with all the stuffing in the world too. Of course if you set a whole room aside for the speaker we are close to infinite baffle and the effect will be very small. But that is fantasy land for most speakers.
Would like to say love your videos I have a question that is off Q but just curious your opinion I have mainly vintage Sansui equipment my speakers are SPX 9700 and SPX 9000 do you feel bet they have the quality of today's speakers
Because you used the word "vintage:" about 45 years ago, in the early '70s, I went to the Far East courtesy of the US Navy. In Hong Kong I purchased a pair of Wharfedale. I listened to everything I could, and back then, all of the Japanese speakers were really bad. Just terrible. Their electronics were much better. Hopefully Japanese speakers are better, now. I prefer American speakers. I suggest that you simply: trust your ears! Take some, a few, of your favorite albums and Compact Disks to a good hi fi location such as Magnolia, and Hi Fi salons, if you can, and compare the sounds from the various pieces of equipment. Try to purchase the best, most pleasing sound TO YOU, that you can afford. And, keep an open mind! It's possible that your current speakers remain satisfactory and pleasing TO YOU!
A reflex speaker having a front port does not thereby become a transmission-line speaker. Acoustically, it doesn't matter where the port is placed, assuming we're talking about a speaker designed to reach fairly low - say below 50Hz. Speakers for boom boxes that can only play down to about 150Hz could be a different matter. The important point to observe with rear-port speakers, is not to push them up against a wall, which can block the port and make it ineffective. Drivers selected for ported speakers should have stiffer surrounds and spiders to help prevent over-excursion at very low frequencies (below the port's tuning range).
You have no experience in old school sound ! BIG bass driver in sealed cabinet was AWESOME !!! Look for KEF reference 3way floorstander from end of 70-ies... R105 i think it was... point is that "small excursion drivers" were great in sealed boxes...
It's called "damping effect" for bass. But basreflex is always better IF IT'S high excursion driver and made for ported/transmission line/horn setup...
Everyone worrying about chuffing or port farts, and here we are making a box for 4 15" subs with 300 square inches of port, enough to fit one adult inside 😂. Chuffing is caused by poor port area, and its related to xmax and power being fed. This is what I've learned in car audio.
The port controls the speaker over a narrow bandwidth. The driver that you use in a ported box can have a lighter cone and therefore the speaker can be efficient and occupy a small volume. It reduces the cone mass requirement and makes the box smaller and this leads to sensitivities in the range of 89 dB SPL as opposed to 84 dB SPL for 1 meter, 2.83 volt sensitivity in free field. Closed box speakers need to be bigger to have the same lower bandwidth limit and efficiency.
I think a rear port has a distinct advantage over a front port. With a rear port, strategically placed, it's possible to effectively control bass reinforcement. Try the same trick with a front ported speaker, nine times out of ten, all you will end up with is excessive bass boom.
Speaker design for seven-year-olds...no mention of Qts, Qtc, Qes, Qms, Fs, Efficiency bandwidth product, the air mass spring model...none of it..."I'm certainly no port expert"...Not an expert?, don't know the math, who Theil & Small was? then why are you here?, handing out advice?
Some manufacturers consider the use of ports to be cheating to achieve bass. Paul likes Henry Kloss's or ( KLHs) original acoustic suspension theories.
The port of a ported speaker is a Helmholtz-resonator, and when the frequencies are higher than the port resonance the output is in phase with the driver and that gives those frquencies a boost, when the frequencies are lower than the port resonance the ports output goes antiphase with the driver and that's explane why a ported speaker suddenly goes quiet at really low frequencies ie. lower than resonance, it's ekvivalent to a fourth grade high pass filter. I have built my own ported speakers and it is hard too get it right, one way to determine if the speaker plays as it should is to put the music on, really loud, and walk to another room and listen to the sound, if you hear just one bass note all the time like; boom boom, then your speaker is not doing so well and it has become a boombox, people who dislike ported speakers refers to them like that. But if you try hard and put your mind to it, it is possible to build a good speaker, I would say that if you were to build a hundred different ported speakers then maybe five of them sounds really good, yes it is difficult. But don't bother with a passiv-radiator or slavebass speakers, they are a nightmare to design and their rollof at very low frequencies is maybe a six grade high pass filter,
I am about to make a sub enclosure from a large PVC Pipe section which is 14 " that allows me to use a 12 inch driver can anyone surgery a website or free designs for tube enclosures, I might encorporate a full speaker build using the tube section with a smaller book shelf type speaker design attaching them together making the tube a pure downfiring sub.
Firstly, thank you so much for these videos. I've only just dicovered them. Now I am.going to ask a very basic and possibly, naive question. What is possibly better between a scoop bin and a rear mounted speaker. 'W Bin'??? I've owned scoop bins before, but never a rear mounted speaker. Is one better suited to a certain situation? Size of room etc.
Farting can be fixed with a bigger port. But bigger port needs a ton more space. For movies a ported box is a no brainer, unless you have like 8 to 16, 18 inch subwoofers or something, but yea. For music, people prefer sealed subs because how tight they fill, and punchy and fast response.
These feel like hanging out with your grandpa on a weekend and he's teaching you about something your parents didn't want to learn but you're super interested in
My grandfather taught me how to break the windshield on a car with a jack handle. then flip his lawyers business card at the shocked driver. He hated car horns.
I have always hung out with older folks quite a bit. I find their knowledge indispensable! Best thing you can do in life is hang with the smartest people you can find and you will learn a ton!
Front ported are much easier to place than rear ported ones as the latter need room at the back (normally 20cm) for all that as sound energy to be released easily. Hence, Big spaces rear ported, small spaces front ported. Example, you can't keep a rear ported bookshelf in an enclosed area...where as a front ported will work just fine.
This make me sad, don't like ported speaker because can hear "fart" sound in the port. How loud is that fart sound anyway, look like high end audio guy is suffer a lot because they can hear everything that normal people don't.
I never like ported speakers either. The speakers that I have are now 40 years old. I designed and built them myself, and they are still going strong. I did though have to rebuild the woofers at one point since the outer rubber cone mounting rings had turned to dust. But for just 27 dollars, and a couple of hours work per woofer, they were as good as new. ibb.co/jSWGOo
Even with the maze on a front ported speaker, you can’t predict the frequency of the speaker and some of the output will be out of phase. I’m a big fan of sealed boxes with larger amplifiers - but I’m definitely in the minority.
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Most port designs take advantage of what is called "helmholtz resonance", much like what produces the sound in a pipe organ. By tuning the port/box/woofer combination, one can use this phenomena to produce bass notes at lower frequency and higher spl than the woofer could in a sealed box at the cost of (usually) a larger box. At least that's how I understand it.
Can we say that a studio monitors with ports gives us different bass frequencies than are actually recorded?... so treating the room or blocking the port does similar things... I use the monitors very quietly because of neighbours, so will blocking the ports take my room out of the equation?... thank you :)
G.day brother what would u recommend in my case.I want to build a low mids box for my car audio use if 6 12” should I build a ported or seal box plz note that the boxes will be facing outwards back the back door window
@@steve5662 the only way to take the room out of the equation is to wear headphones
@@steve5662 Your studio monitors are designed with the port in mind, blocking it will likely give you a less accurate response.
Intuition tells me placement is even more important for rear ported speakers as they are "playing the room" more (back wall reflections). Same for dipoles, magnetic planar, electrostatic, open baffle, etc. True or false?
"Shift Registers" at 4:14.... Been a while since I heard that term. Paul must be an old assembly language geek ;D
dcairns61 I think most CS students can relate 😜
Every programming language has bit-shift operators. Although it's generally true that you can only take advantage of the carry bit and use circular shifts in machine language - unless the compiler is intelligent and can understand that sequences like this can be implemented with a circular-shift instruction:
#define MSB_MASK 0x80000000;
int Cbit, shiftreg;
Cbit = shiftreg & MSB_MASK;
shiftreg
and JK Flip Flops too!
The pressure inside a ported box is actually higher than a sealed. Low frequency waves actually go through the box a whole lot easier (below the tuning frequency of the enclosure, Fb.), this is called unloading. Below Fb the speaker increasingly "sees" no enclosure at all and will rolloff at ~24dB/octave. To avoid damage to a vented box with somewhat high Fb you need to highpass the frequencies below Fb as these will cause excessive excursion to the driver.
Port "chuffing" can be largely avoided by simply decrease its air velocity to below 17m/s. Many use flanged ends to help alleviate this problem as well. A well designed port/enclosure will won't have these issues to any audible degree.
A T/L and vented enclosure is not the same thing. Front port or rear ports really does not matter at all in a technical perspective. The wavelengths at low frequencies are so long that the port placement only amounts to a fraction of a frequency cycle's phase difference. You must have some distance (normally at least the vents diameter) between the wall and the backside of the enclosure which can lead to issues if you try to hang it on a wall or something. The main reason they place the vent at the back is to be able to save space really.
Futhermore, a vented enclosure is by itself more efficient and has lower non-linear distortion than a sealed enclosure due to less excursion around Fb. This of course increases the maximum output of the driver within its voice coil thermal ratings.
The only thing that a sealed enclosure is better at: as mentioned, the actual group delay/phase shift. The vent cause a phase shift in its passband which increases its group delay in these frequencies. This group delay's audibility must be seen in relation to the actual frequency. At 50Hz a full period is 20ms (1/50=.02s), while at 25Hz a full period is 40ms (1/25=.04s). With certain alignments the group delay can exceed a full period, at some point it starts to get noticable and this is what people refer to as "sloppy bass".
A lot of times this issue is fixed by simply equalizing the frequency response as group delay is a derived function of the magnitude and phase response. The enclosure-inherited group delay of a vented design can be fully corrected for with FIR-based signal processing. In my opinion, the vented enclosure is usually far superior to a sealed box, especially if you got a powerful DSP / room correction. Note that not all drivers are suitable to use in vented enclosures, most high Q-drivers should be avoided for example.
Man do you know your stuff!
I was just trying to figure out what "that hole in the front" was, I felt like a dumbass for calling it a hole haha
I love your expert opinion on amplification but your explanation on ported speakers is flat wrong. #1 the sound coming out of the port is in phase with the woofer whether front or rear ported. #2 The port is not a pressure release (in the frequencies in which it performs it's duties). #3 A port does not work like a transmission line to invert the phase. A port tunes the box at a certain frequency determined by the diameter and length of the port. At this tuning frequency, the woofer and port output are in phase. Because the woofer is moving in the same direction as the air in the port, the pressure inside the enclosure is GREATER than the pressure of a not ported(sealed enclosure). Don't believe it? Run this test. Find the tuning frequency of the ported speaker by running an impedance sweep. There will be 2 humps in the low frequency area. In between the 2 humps will be a valley, this is the frequency at which the ported speaker is tuned. Let's say the impedance dips between the 2 humps down to 6 ohms at 40 hz. Plugging the port with your hand, run a 40 hz test tone through the speaker until you see the woofer really moving. Now take your hand off the port and notice that the woofer now is barely moving yet the speaker is producing even more bass. The reason is, the air spring (pressure) in the box has increased due to the port output being in phase with the woofer.
I just listen with my ears and that determines which speakers I like. I have both ported and sealed speakers. Best of both worlds.
Ports box is more produced Louder bass than sealed box but there is delay bass frequency comes out.
Sealed box is always had smaller box needed and more accurate bass than port bass
I've recently been doing plenty of experimentation with ported box designs, including making my own 6th order bandpass box, and here is what I've learned about how ports behave.
They are in fact in phase with the diaphragm, due to their resonance their phase is inverted, causing them to add to the air displaced. If they subtracted, there should be an output dip either side.
This also causes an impedance dip, as the pressure within the box, experiences a peak caused by the added displacement. The driver moves slightly less due to the pressure, and causes an impedance dip as EMF decreases voltage being fed back to the amplifier.
Efficiency is increased as power is "shifted" from moving a diaphragm with relatively high mass to a tube of air resonating, with a relatively low moving mass.
Ported boxes have a steeper roll-off than sealed, as the port doesn't allow pressure to build up lower than its resonance. Low frequency air flow may come and go as it likes. It behaves sealed at higher frequencies, however only reflected waves come through.
Due to bass having an inherent non-directionality associated with its creation, the speaker box is simply adding or subtracting the local air pressure around it. Phase from front to back shouldn't matter. Enclosures where it does are referred to as "dipoles".
Port surface area is relative to length for tuning, possibly why front ported boxes have longer ports is due to a greater surface area attempting to eliminate "chuffing" with lower velocity airflow.
As far as I'm aware passive radiators behave like ports, though without chuffing, are less efficient, and from what I can tell work better with smaller boxes than ports.
Transmission line speaker enclosures work by having a set transmission line length, usually tuned to either 1/4 or 1/2 wavelength of the desired tuning frequency, feed the rear wave down a tube with said resonance. Port width is usually equal to the driver surface area and constant along the line, unless a tapering/horn loaded design is used. The effect on the air from thought experiments is like hanging a weight from a bungee cord, move your hand at the resonance of the weight, and although your hand is moving only a 1/4", the weight may be moving 1" or more. This works similarly to a ported box, though requires much more space. Generally transmission line boxes reach the lowest notes, though this may be due to them performing as dipole enclosures down low.
Dipole enclosures (also from thought experiments) effectively add a springy moving mass to the driver, lowering its resonance, which improves low end. The distance between the front of the driver and the rear creates the pressure differential, and therefore sound.
I kinda fell half asleep whilst writing this, so hopefully it makes sense
I see that you answered my question about passive radiators , Thanks. I was thinking on smaller speakers like the Vanatoo T1 and T0.
Dude , your off in left field with all that.
yes, but i'm enjoying his dancing in left field too... he's giving you some insights into other ported designs...
Arghhhhh! 6th order, as long as you know the phase response will be pants!
"They are in fact in phase with the diaphragm, due to their resonance their phase is inverted, causing them to add to the air displaced."
This is not true. At the precise resonant frequency, resonators respond IN PHASE to the driving function. Thus port emissions exactly at their resonant frequency will tend to cancel the woofer front wave and produce a narrow dip (notch) in the response.
Resonant systems exhibit a large shift in phase response, comparing at frequencies just below and just above resonance. Ultimately, an undamped system can exhibit nearly +/- 90 deg. phase shifts across a narrow frequency range.
In the region below resonance, the port can add boost to the woofer, but at or above resonance it tends to partly cancel the woofer front wave. If you do careful response measurements at small frequency steps for a ported speaker system, you may find significantly uneven results.
Actually the port sound output is in phase in its adjusted frequency. Due to resonance of the enclosure and the "Piston mass" inside the tube.
Lets say you want to adjust the bass reflex supporting frequency to 35 Hz. You got a 50 L Box, than you need a round port approx 4" width times 12" length. Big floor standing speaker.
Out of the adjusted frequency the "Air Piston" in the tube can not move properly, or even not at all.
The fuction of the port increased if approaching the frequ. and its decreasing if leaving.
But in this case it doesnt matter in my eyes, if the port is in the front or in the back.
Because the wave length at 35 Hz is 10 yarts and you got a 1' deep Speaker maybe (front to back). So the back port would be 1/30th out of phase reaching your ears.
Bass is emitting nearly 360° the same around the speaker. so doesnt batter to me.
A passive Butterworth Frequency cross over for example, with -6 db per octave, generates a 90° delay in Phase in the low pass way, thats nearly 4' - Bass/Mid separation at 300 Hz . However it is the commonest frequency cross over. That tears apart the exact imaging of the stage arround the crossing frequencies.
Some very smart invetors and developers build speakers that wave no delay in Phase, absolutely time coherent. A giant step towards natural sound play back.
cheers.
Jean Katana Above the the tuned frequency the air mass within the port cannot move freely, but below it, it can.
This is one of the caveats of ported loudspeakers, below the tuning frequency, of the port, the cabinet and port offer no control over the motion of the cone. The driver unloads, excursion shoots up with falling frequency, and the output rapidly reduces.
5:45 this is incorrect. Vents do not relieve pressure inside the box, on the contrary it increases the pressure until you get to a little below the fb. Air has mass and the ports use this mass to load the driver. Push a lot of air through a little hole and it moves very quickly, when the driver begins moving back the other direction the air in the port is still moving the same direction this is where the increased pressure comes from and why you get more sound pressure. Sound is pressure, less pressure less sound.
Odd that such a seasoned audio professional would make such a glaring error. Hmmm. I listened to it a couple times and that's what he said. Misspoke, or actually doesn't understand fundamental physics of mass and momentum?
I'm not a Port guy either. Prefer Single Malts.
Then, any speaker sounds good...after a few.
If you don't like the sound of ported speakers, can you just fill the port with foam filler, or is this not a good idea?
Nope if a box is designed to be ported then it can't be sealed as the enclosure dimensions are calculated by the driver specifications . So if you want a seal enclosure then you have to calculate according to the drive specifications .
brian weir
my Focal tower TL speakers have a front port. So do my old college airborne/phillips set. my B&W's have a rear one, and my Infinitys don't . All those great folks who designed them were not hacks; similar to your comment on A vs D, I think the original design and intent is the most important thing. They are all different and likeable to me. I like my Focals best in general.
1 second ago
brian weir I too have a pair of transmission line speakers with Focal drivers and I absolutely love them! I designed and built them myself with a great deal of care and effort. I have designed and built a number of ported designs and a few sealed designs but none came close to the sound of the TL’s. To me TL’s seems to have this effortless quality to them. They sound more open and dynamic (sort of like comparing open back dynamic headphones to closed pressure style I guess).
Every port shifts the phase by 90 degrees at its tuning frequency, no matter on which side of the enclosure it sits. If it's on the back you usually lose a few decibels in the bass because the phase shift increases due to the time it takes the sound to travel from the back to the front. Wave lengths in bass are big in comparison to the dimension of the enclosure therefore they bend around the edges (spherical radiation). But ports also let a small amount of mids pass through which is perceived as distortion. In the mids the sound waves are smaller and don't bend around the edges. Therefore they don't reach the listerner if the port of a mid-woofer is on the back. With a port on the front this distortion might lessen the sound quality. The solution: port on sides, top or bottom as near to the front as possible.
The huffing and puffing noises are generated by turbulences of the air flow inside the port and on its edges. Therefore those Elac speakers have a port with round edges. If the diameter of the port is too small the air flow gets too fast and turbulences occur even on the surface of the inner wall of the tube. The cross section of the port should be at least one fifth of the effective piston area of the driver. Even better is one fourth or more but the length then might become too big for the same tuning frequency. The standing wave inside the tube becomes a problem then.
Before I discovered your "Ask Paul" series I started a similar podcast in German, apart from most of my other videos being in English. Im currently translating my first few episodes into English but it takes a lot of time because they were not scripted. On many of them RUclips's automatic subtitle function didn't even work. (The German version seems to be not that good yet.) If I gathered some more subscribers from the English speaking world it would maybe motivate me to speed up my work.
Source of all my knowledge: German DIY loudspeaker magazine Hobby HiFi.
Thank you for that interesting comment 4 years ago, Marius 🤗
Front ported is better. Mission 704’s!!!
A well designed ported speaker would not have any fart sound. I can guaranteed that.
What he said :)
Half-decent sealed box speaker usually sounds more accurate to my ear problem with ported usually used to make s*** speaker extended
Methinks Mr. PS audio needs to check out all the studio speaker (4343,4344, 4350 etc.) JBL put out over the years with larger ports 4-6 inchs that sound absolutely fantastic. :>)
George Zubeck people there are always exceptions to every rule and if you listen most times he says it in one way or another.
don't worry, paul has forgotten more than i know....
I prefer the curve of my ported subs. High at 30hz and steep roll off from 40 to 80 hz. I've spent my life chasing after perfection and to me this is as close as I can get. They lack the punch of a flatter curve, but I'll take that trade off. There is only one song I know of where my setup has an obvious lag between notes and it bothers me but I would still not trade it for anything else, especially not a sealed subwoofer. So much of this has to do with what music you listen to, and I think when people have disagreements they sometimes fail to take that into account.
I can appreciate the use-case scenario. I personally prefer using a bigger amp and more EQing to get a similar curve from a sealed enclosure. I’m sure they’re out there, but I’ve never heard a ported enclosure with good subsonic extension. Ports can create phase issues that can be very difficult to address. Of course, if power limits at a large venue are limiting, a ported enclosure would make sense.
What is your thought on Passive Radiators?
just looked thru some comments ( about 30 + ) didn't see anyone mention ' Thiel / Small' one of if not the first computer type speaker box/ port designs.... My Koss speakers ( 1978 1020 ) Koss claimed were the first to use this development. Seemed to work, the Stereo Review mag , Sept '78 > had a comment ' response curve flat + - 2 from 20 to 5000 hz'.... (closer to an amp than most speakers, even Advents of the day.my thought.) and distortion ' among the lowest we have yet measured' PS the Koss were fairly large, the mid range 1020's 33in high, 15 wide - 10 in bass with 2 front ports.
Just as a guess, ported designs seem very common today.
Love this channel I am learning a LOT.
I wish you’d do a comparison of sealed , ported , and passive radiators.
I’m personally a fan of how passive radiators sound. But there’s very little information available on them
I prefer sealed over ported, but some ported models are great also. Rear ported designs are much better than front ports, to me anyway. Sealed just has a cleaner smoother bass and just plain sounds better I think.
I have a pair of B&W 804 D3 floor standing speakers. They sit 3 feet from the back wall but are close to the side walls. I didn’t like the mid bass boom I was getting so I have now put the supplied foam bungs in the ports that are on the front of the speakers. They sound way better now. If I add a sub (or two) to extend the bass down, would I still get any bass bloat in the room, seeing as the 804s are now “sealed”? Thanks.
Given a round to square opening, front/rear ports use (mathematically calculated) LENGTH of the tube ( inside the speaker) for optimization.
When properly designed and manufactured, ported speakers can be used in two different ways: if you have the room to have your speakers out from the rear wall, as in on stands, rear ported speakers will be your best bet. If you don't have the room, and may even have to wall mount then a front ported design would be your best bet.
Conversely to having a port. Does the sealed speaker with the compression and vacuum going with the cone operation, vacuum when out, pressure when in, actually create a quicker stop and then quicker restore of the cone and reduce vibrations as the cone goes back to its central position. Thus making the base truer to the original as it is now self controlled. Overthrow and sluggish return are now self regulated by the size of the box in relation to the cone movement.
Ports are a way to alter the physics needed of enclosure size to produce sufficient bass. I used to own a few of the Dunlavy speakers that were all sealed boxes - no ports at all. And they had terrific bass, but they were large enclosures (not very high on the wife-acceptance scale). If you didn't mind your speakers almost as large as your refrigerator, the bass was articulate, fast, and very real, with none of the problems with ports. Still the best I've ever owned.
Hi Paul. I have a pair of Roland DM-20 front ported. Because I'm curious I pulled them open and found them empty except for the built in amp. I decided to stuff them a little bit with some pillow material. These are monitor speakers used, and was wondering if filling them is OK? They sound good, especially once I took them off the floor. Should I not have stuffed them, or does it not matter? I use them for listening to music, not mixing or anything. Thanks!
Not to beat a dead horse but I have a set of AAD 2001 monitors , 4.75 inch driver , rear ported . I invite anyone to detect any audible port discharge noise from these Phil Jones marvels. easily 32 hz from a small monitor with a small bass inch driver..... DESIGN ….
And here I thought you were going to speak loudly about Port wine. 😄
Kali Audio purports (NPI) to have solved the port 'chuffing' issue with their front port design. You might look into that if you are curious.
Ports have some specific disadvantages. First of all, the loudspeaker is acoustically unsupported below resonance. The box is open. Any frequency below the box tuning causes excess cone motion. The second major disadvantage is that the box is a Helmholtz resonator that only resonates at one frequency. That adds pressure to the bass, but not at the same frequency. One difference between a port on the front, back, sides, top or bottom is its proximity to the wall which can aid or hurt the amount of pressure. Another difference is if the midrange that leaks out of the hole can be heard by the listener or not.
how do I calculate optimal port dimensions (length and diameter for a round port) to gain maximum efficiency and maximum output for a given subwoofer
Front ports, when done right, do allow for greater freedom in speaker positioning. So, they are potentially better than rear ports. Done wrong, they make those wind gusts more audible than rear ports. So, they are also potentially worse than rear ports.🤓
You have 15 inch subwoofers lying around and ha ha I'm searching like crazy for 2 from Europe
It's been my observation through the years that I prefer rear-firing ports as opposed to front firing port. IDK if the bass slams into the corner of the room behind the speaker and has more wave-length to travel or what. I was skeptical of my Kicker's Sub-box having a huge side aeroport, but it doesn't seem to effect any sound quality. so... IDK.
More in-depth info here:
barefacedbass.com/technical-information/the-mysteries-of-ports.htm
...and a 40 min seminar here:
facebook.com/BarefacedAudio/videos/10155712331072704/
Respect a man who uses shift registers to explain something.
G.day I’m all the way from Guyana I need to know if I should use a Ported or seal box for my low mids,plz note that the boxes are facing out the car by the back side window
So my question is what is a proper preamp to amplifier to mixer hook up. I write and play music for the love of it. And just want my sound to sound live and clear. But I do have a small room size for my set up. I do share the signal with a home audio receiver.
In a ported design the speaker cone barely moves near the ports tuning frequency. So the box and cone actually see much more pressure than a sealed enclosure. This can have a couple advantages like reduced distortion if designed correctly. This is a misnomer and common misconception that sealed produces less distortion. There are many advantages like the amp is only needing half the power at the same loudness further reducing distortion. If you dont believe me listen to a self powered gelelec studio monitor. No chuffing either .
It is kind of weird, I did a little bit of research the past weeks and I already know what he is saying isn't really correct, he admits he doesn't know much about it, no problem, respect. But considering his business one would expect at least a decent amount of knowledge about the basics of ported speakers. I went to the website, the only speakers I found there where front ported speakers...
You also have ported on the bottom of the cabinet, downfiring speakers. So back port, front port and bottom port.
Nonsense. If your port is chuffing you haven't designed the port or the enclosure correctly.
What a small magnet on that 15 Inch woofer. Stamped basket and not cast looks cheap for Infinity!
A port is a very old way of tuning the frequency of a speaker without using a crossover it's crude, old and out of date
Intensity of ported speaker flatulence = internal mass of air (squared) × port diameter.
A sealed cabinet will give the best bass. But it is tricky to calibrate and you would need a strong amp.
ported suits me better for what i listen to, maybe for those rare parties with hip-hop aren't perfect in terms of bassy but for voice and movie sounds it's more nonresonant, someone walking in forest steps on a dry branch - it's he in a forest or a corridor?
Stuff the ports with rolled news paper,....can Improve midrange
Is it ok to partially block my ports to cut the bass down a bit at night? I use Klipsch rear ported speakers.
You said that only high frequency goes out than you said that bass output goes out too but bass is a low frequency and you said low frequency cannot pass to the vent can someone explain me what im confusing
I've read that rear ports need space behind them to keep them from "chugging".
Can u even hear the cuffing unless u put ur ear up into the port hole . I've never heard it , ported subs is all I have .
I live in Port ugal. Will plugging ports harm the woofer in any way?
My Paradigm Founder 100f is ported out the bottom
Nice video Paul. How about ported speakers vs passive radiators?
passive radiators is basicly a port simulator. But since its smaller than a port you can get small airspace and the same output
hate chuffing sound, love acoustic suspension on my advents nice tight punchy bass
Paul, why do some B&W speakers have dimples on their ports?
Porting a small speaker cabinet causes mud , never port a monitor for mixing
The port has an air mass that is suspended with the airvolume inside the box.
When this mass reach resonance due to the triggered soundpressure from the woofer, it starts to resonate. At resonance, the air in the port goes out when the woofer does. This will enhance the bass level. The wavelength at 50Hz is about 7 meters, so it does not matter if the port is in front or on the rear.
However, at lower frequencies than the ports resonance frequency, the air in the port starts gradually to get sucked in while the woofer goes out.
From personal experience... I listen nearfield with the speakers at ear level. When I had front ported speakers? When certain notes were hit, it was like sitting in front of a hair dryer set to cool. On cold nights I would get cold air blown in my face. So... rear ports have another good purpose. I prefer sealed or passive radiator speakers. More accurate sounding.
I recently purchased Kali Audio front ported Studio Monitors. I used to have the Yamaha HS8's, but the 8" woofer with the rear port produced to much boomy bass as my studio is small thus my speakers are forced to be closer to the wall. The front ported Kali Audio monitors with 6.5in woofers and front port design fixed my issues perfectly. In addition they have a trim pot to compensate for speaker locations and room environments. So sometimes front is better depending on the the acoustics of your listening room.
These videos are awesome, I'm learning many things I've wondered about for years.
Sealed has a cleaner sound but requires more power. I personally think it depends on what kind of music you listen to. I dont know. I like a sealed box for rock and metal. But if you get into the hip hop style the speaker cant react fast enough and starts to bog. If that makes any sense. Love all your videos Paul.
NTH Welding , I had an old vintage pair of Advent 3 way speakers with a 12 inch woofer, 4 inch mid and 1 1/2 inch dome tweeter, sealed.
I compared them to a set of equal speakers made by Cerwin Vega, no comparison, the Vegas blew them away. but on the other hand, the Advents although took more power to run as loud had a much tighter hitting bass frequency, so I just used all four speakers in the same room. the sound was great!!!!! it really comes down to if you have tube amps or digital amps and what type of music you like.
Rear ports are more picky in regards to room placement. If a rear ported speaker is placed too close to a wall, there can be either an increase in bass amplitude or a cancellation of lower frequencies due to reflections and phase alterations of the sound leaving the port. Make more room behind them, and they will have smoother bass characteristics. Front ported speakers do not experience this problem, so they can be placed closer to walls. But because the port is facing the listening space, it might be easier to hear the port noise. I've got some rear ported bookshelf speakers, and they're pretty close to a wall, so I ended up plugging their ports. Their bass sounds muuch less boomy. And the reduced bass range is being taken up by my subwoofer. It's a win-win.
I just bought a pair of made in 2002 Paradigm Mini monitors Ver.2 I have read that years back Paradigm used to supply plugs for the rear ports if needed for placement reasons in a said room. At any rate I believe in your comment greatly. Rear ported speakers can be be more picky on the speaker to wall distances. We will see what happens. They will be here tomorrow and yes already running a pair of Yamaha powered subs so I know for sure I can work something out. Thanks greatly on your comment CaveyMoth.
@@VintageGearMan You're welcome. Dang, I've always wanted to try Paradigms. Their little monitors are supposed to be really good.
@@CaveyMoth Supposedly the Mini's Ver.2,, 3's, and 4's are supposed to be all that. I did a ton of digging on these speakers. I have ran 70's, 80's and a few 90's loud speakers all my life. I hope these will be a bit more resolving. Great hearing from you.
I will be happy to update/comment on these Mini's Ver.2 after installing.
It is a little scary going outside of the 70's ,80's 90's speakers box realm. This will be a new frontier for me.
That Infinity speaker has an embarrassingly tiny magnet. JBL
It doesn't have to be big!
Glad to see you're promoting the elac line I have a set of UF5 Towers and the UB5 bookshelves and hoping in the near future to purchase your Sprout 2 for my UB5's great job🎧🎶
i like air-suspension/sealed as you get a better mid-bass
Ive got a question for Paul McGowan and viewers out there. I'm building a 2x12" speaker cabinet for a 100w peavey valveking head and wondered should I port the cab? I don't really want too as it will be a closed back cab, but does and will it make a huge difference in the sound if I do? And if I put a small hole in the cab say 10-15 or 20mm for example just to let the speakers breath/move properly within the cab and not let out alot of noise will this help with speaker over all speaker perfomance and or sound? Thanks and love your videos.
I really hope you didn't port that thing
Paul reminds me so much of my dad... but happier
I have a great fan of passive radiator speakers.
Thanks for sharing some magic of acoustics.In phase & out of phase sound production.
Thanks Paul. Also, I really like your ending music.
What most people seem to forget is that sealed speakers also have a port.
That is the driver itself. The driver's backwave will resonate and reflect back through the cone in a number of rather unpredictable ways. And that is with all the stuffing in the world too.
Of course if you set a whole room aside for the speaker we are close to infinite baffle and the effect will be very small. But that is fantasy land for most speakers.
What do you think of horn loaded stuff?
Would like to say love your videos I have a question that is off Q but just curious your opinion I have mainly vintage Sansui equipment my speakers are SPX 9700 and SPX 9000 do you feel bet they have the quality of today's speakers
Because you used the word "vintage:" about 45 years ago, in the early '70s, I went to the Far East courtesy of the US Navy. In Hong Kong I purchased a pair of Wharfedale. I listened to everything I could, and back then, all of the Japanese speakers were really bad. Just terrible. Their electronics were much better. Hopefully Japanese speakers are better, now. I prefer American speakers. I suggest that you simply: trust your ears! Take some, a few, of your favorite albums and Compact Disks to a good hi fi location such as Magnolia, and Hi Fi salons, if you can, and compare the sounds from the various pieces of equipment. Try to purchase the best, most pleasing sound TO YOU, that you can afford. And, keep an open mind! It's possible that your current speakers remain satisfactory and pleasing TO YOU!
Is Paul a port authority? Watch.
Very well explained, thanks for the video :)
Sealed all the way. Never cared for the ported sound.
Video does not answer the question.
in your little what registers ?
Passive radiators are better than ports.
I would go for pr's. Ports fart
A reflex speaker having a front port does not thereby become a transmission-line speaker. Acoustically, it doesn't matter where the port is placed, assuming we're talking about a speaker designed to reach fairly low - say below 50Hz. Speakers for boom boxes that can only play down to about 150Hz could be a different matter.
The important point to observe with rear-port speakers, is not to push them up against a wall, which can block the port and make it ineffective. Drivers selected for ported speakers should have stiffer surrounds and spiders to help prevent over-excursion at very low frequencies (below the port's tuning range).
damn, i hate the sound of sealed... it sounds restricted, stifled, like its being kidnapped and the chloroform is starting to kick in.
Then you have listened to a poor design.
You have no experience in old school sound ! BIG bass driver in sealed cabinet was AWESOME !!! Look for KEF reference 3way floorstander from end of 70-ies... R105 i think it was... point is that "small excursion drivers" were great in sealed boxes...
You're hearing the sound of the placebo effect.
Mohammad. I agree. A sealed cabinet has no volume. A sealed speaker sounds congested.
It's called "damping effect" for bass. But basreflex is always better IF IT'S high excursion driver and made for ported/transmission line/horn setup...
Everyone worrying about chuffing or port farts, and here we are making a box for 4 15" subs with 300 square inches of port, enough to fit one adult inside 😂. Chuffing is caused by poor port area, and its related to xmax and power being fed. This is what I've learned in car audio.
The port controls the speaker over a narrow bandwidth. The driver that you use in a ported box can have a lighter cone and therefore the speaker can be efficient and occupy a small volume. It reduces the cone mass requirement and makes the box smaller and this leads to sensitivities in the range of 89 dB SPL as opposed to 84 dB SPL for 1 meter, 2.83 volt sensitivity in free field. Closed box speakers need to be bigger to have the same lower bandwidth limit and efficiency.
I think a rear port has a distinct advantage over a front port. With a rear port, strategically placed, it's possible to effectively control bass reinforcement. Try the same trick with a front ported speaker, nine times out of ten, all you will end up with is excessive bass boom.
Speaker design for seven-year-olds...no mention of Qts, Qtc, Qes, Qms, Fs, Efficiency bandwidth product, the air mass spring model...none of it..."I'm certainly no port expert"...Not an expert?, don't know the math, who Theil & Small was? then why are you here?, handing out advice?
Some manufacturers consider the use of ports to be cheating to achieve bass. Paul likes Henry Kloss's or ( KLHs) original acoustic suspension theories.
The port of a ported speaker is a Helmholtz-resonator, and when the frequencies are higher than the port resonance the output is in phase with the driver and that gives those frquencies a boost, when the frequencies are lower than the port resonance the ports output goes antiphase with the driver and that's explane why a ported speaker suddenly goes quiet at really low frequencies ie. lower than resonance, it's ekvivalent to a fourth grade high pass filter. I have built my own ported speakers and it is hard too get it right, one way to determine if the speaker plays as it should is to put the music on, really loud, and walk to another room and listen to the sound, if you hear just one bass note all the time like; boom boom, then your speaker is not doing so well and it has become a boombox, people who dislike ported speakers refers to them like that. But if you try hard and put your mind to it, it is possible to build a good speaker, I would say that if you were to build a hundred different ported speakers then maybe five of them sounds really good, yes it is difficult. But don't bother with a passiv-radiator or slavebass speakers, they are a nightmare to design and their rollof at very low frequencies is maybe a six grade high pass filter,
I am about to make a sub enclosure from a large PVC Pipe section which is 14 " that allows me to use a 12 inch driver can anyone surgery a website or free designs for tube enclosures, I might encorporate a full speaker build using the tube section with a smaller book shelf type speaker design attaching them together making the tube a pure downfiring sub.
Firstly, thank you so much for these videos. I've only just dicovered them.
Now I am.going to ask a very basic and possibly, naive question. What is possibly better between a scoop bin and a rear mounted speaker. 'W Bin'??? I've owned scoop bins before, but never a rear mounted speaker. Is one better suited to a certain situation? Size of room etc.
Farting can be fixed with a bigger port. But bigger port needs a ton more space. For movies a ported box is a no brainer, unless you have like 8 to 16, 18 inch subwoofers or something, but yea.
For music, people prefer sealed subs because how tight they fill, and punchy and fast response.
These feel like hanging out with your grandpa on a weekend and he's teaching you about something your parents didn't want to learn but you're super interested in
My grandfather taught me how to break the windshield on a car with a jack handle. then flip his lawyers business card at the shocked driver. He hated car horns.
@@sansocie .....Nice guy...
I have always hung out with older folks quite a bit. I find their knowledge indispensable! Best thing you can do in life is hang with the smartest people you can find and you will learn a ton!
Front ported are much easier to place than rear ported ones as the latter need room at the back (normally 20cm) for all that as sound energy to be released easily. Hence, Big spaces rear ported, small spaces front ported. Example, you can't keep a rear ported bookshelf in an enclosed area...where as a front ported will work just fine.
This make me sad, don't like ported speaker because can hear "fart" sound in the port. How loud is that fart sound anyway, look like high end audio guy is suffer a lot because they can hear everything that normal people don't.
I never like ported speakers either. The speakers that I have are now 40 years old. I designed and built them myself, and they are still going strong. I did though have to rebuild the woofers at one point since the outer rubber cone mounting rings had turned to dust. But for just 27 dollars, and a couple of hours work per woofer, they were as good as new. ibb.co/jSWGOo
Even with the maze on a front ported speaker, you can’t predict the frequency of the speaker and some of the output will be out of phase. I’m a big fan of sealed boxes with larger amplifiers - but I’m definitely in the minority.