Does doubling power or doubling cone area really gain 3 dB? - Tech Stuff Tuesday
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- Опубликовано: 19 сен 2024
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This is why i have a few notebooks full of testing in my car.......people dont know the true spl struggle...great video
I know right,I just focus on the sound I want now,no longer chasing numbers.
Lol, I do. See my above comment haha.
The theory is for ideal circumstances, not for a car environment. Remember, every rattling part in your car is an energy dissipator. It recieves the clean sound wave energy and throws it back as harmonics and noise and heat and all nasty stuff. And it does so non-linearly, meaning the more energy it receives, the more percentage of that energy is dissipated and lost (because the rattling part is getting farther and farther from its resting position). Hope it answers all the questions here🙏
You read right mind and saved me from typing the same response that you did. I was gonna say exactly the same thing, good job.
Not that I would know, but that sounds like a pretty good explanation.
the rattling part doesn't effect the sound coming out of the subs because subs themselves are non linear. sub bass does not change based on direction. only decibels interpreted change.
@@christopherwise7067 Remember pal, we're not necessarily measuring the energy coming out of the sub, but the energy present at the location of the meter. Room acoustics (e.g. the rattling parts) can have tremendous effects on the latter. Especially, the stiffness of the car panels can determine the virtual "cabin volume" perceived by the sub, and room modes etc. which in turn determine the acoustic impedance (i.e. general air stiffness) of the environment around the sub. The acoustic impedance in turn has an effect on the sub output, which is contrary to what you were thinking. No, the environment DOES have tremendous effects on the total energy coming out of the sub...
If you're not convinced yet, just think about it this way: sub itself is a compliant system, meaning it adapts itself to the environment. It's not gonna dictate its movement regardless of the environment. It simply can't do that. If you pour cement all around the sub, it can't just rattle all the cement! It shuts down! Why? Because the sub has finite stiffness and power.
Don't forget the fact that he was using less than ideal enclosures. I'm sure we all know by now that a sub in a box of the wrong size won't play as efficient
The second unpowered box driver is absorbing some of the air movement its how base catchers work in room cancellation in home audio
Easy explanation. It's the theory of how bandpass enclosures work, except your rear chamber is the enclosure, and the ported chamber is the cabin. The ratio of the cabin to enclosure. When you add more subs and step up the enclosure volume, the ratio drops, and the response loses its peak at the natural resonance, but becomes more musical. Check out Derrick from the (The edit is the page name... Sorry)....."Sundown Audio Unofficial" page with the truck "Project SPL." He went from 4 U series 18s, to 2 U series 18s. His efficiency is better, less stress on the subs loading, lowered his power, but his SPL stayed in the same range, and depending on the weather and day, went up. Removing the other subs, and enclosures, gave him more enclosure volume, thus raising his enclosure bandpass ratio, and raising his peak.
Having 2 subs, the one not playing is absorbing energy. That's why u got those results.
That isn't the answer, there are applications where that gains. It's literally the principle of how passive radiators work.
@@EMFAudio not the same as a passive radiator as it is not in the same sealed enclosure as the driven sub.
@@EMFAudio not a comparable situation, not being directly connected to the same cavity will hinder the other sub.
If you have two tuning forks(in this case ports) and you ring one and bring it close to the other it will ring but the sound doesn't increase.
@@94e88 great point👍🏻
Interesting test. It should be stated that in terms of cone area the 3dB gains only occur when the speakers are located within 1/4 wavelength away from one another, and only yielding full +3dB when full constructive interference occurs. In practice this never happens, but the lower the frequency the closer to +3dB you will achieve. The rule should state "up to 3dB", and up to around 1000Hz where the physical size of drivers prevents you from putting them closer to one another. You should test at 20Hz, 40Hz, 80Hz, and 160Hz to expand the results. This is well-known theory based on sound physics, but a lot parameters need to be controlled (power compression, environment, etc...) Another idea would be to test in free-field or 1/2 space to test this, but then again this kind of defeats the purpose as these subs are meant to be used in a car.
The only problem with testing different frequencies to show that point is there is cabin gain also effecting it, much like the other factors.
I saw your video the other week and you mentioned that this culture is toxic. I just got back into it.. And you are very right.
It's not the culture that's toxic here😂😂😂😂😂
It's just physics trying to play fools with us.
The 3dB rule only works in an ideal environment, not in a car in which many non-linear sound absorbers exist.
Car audio attracts a lot of whiny angry boy men. lol. They all got something to say and feel the need to be salty or rude about it. In my videos I teach. I don’t have time to be salty. Car audio is too fun. No idea why everyone is so mad.
@@KBMOTORSchannel I've dealt with an unbelievable number of soy boys in the local car audio community over the years.
Guys far too brand loyal, aggressively critical of other folks setups, know-it-alls, etc.
I give guys thumbs up even if they're bumping old xploded Sony, gotta start somewhere.
Defect exactly! I’ve just recently learned to build subs. So I built a hybrid. Oh boy you should never change a JL w7 12-3 into a 15. You wouldn’t believe how mad it makes some people 😂. Best we can do is learn every day. Share the knowledge. If only I knew back then what I know now I could have saved a lot of money.
@@JesusSaves86AB Sony Xplod is bae😍
Starter kit for many of us... We owe sony a lot for providing cheap entry level stuff to all over the world
on the reversed box, hooked up test, you flipped polarity. BUT remember the port is in phase with the sub, so you should have used the same polarity. AT the ports tune, the second port, and the first driver would be in phase.
Coming here to say "YoU lOsT iNtErIoR sPaCe InStAlLiNg ThE SeCoNd SuB bOx" 😂
that's called volume.
@@christopherwise7067 Did you see the joke as it flew over your head?
I honestly think it was more depending on the other sub moving so you loose power in moving mass
Wanna know how's that loss possible? Loss happens only when the added sub sits there with no input power. If you pay close attention, you can see the inactive sub is moving as well as the active one. Where did that moving energy come from? The box's not powered! Well it gets its energy from the air moving around it. That's the sound energy! Our precious energy goes to the other speaker and dissipates as heat in the suspension and box. Actually, that's how modern "helmholtz" absorbers work in the acoustic rooms and recording studios.
I've seen instances where that sub moving acted like a passive radiator and it was actually louder than not being present, with a plug over the hole. This was in a common enclosure situation.
Well, that's possible as well but not in all case scenarios and all frequencies. After all, our passive speaker is equivalent to an RLC circuit (in its simplest representation) and can act as a resonator as well!
.
Want a nice experiment? Put a large variable resistor across the terminals to the passive speaker, play around with the resistor value and frequency and eventually you'll find a point where the sub loses minimally (or even gains you some). But to use this effect to your advantage in a real life scenario is insane, because of all the variables you gotta trial-and-error on.
I have a feeling you could see different results if done out in the open, as I know (and shown in this video) anything around the sub will affect it. The main reason I put my home 5.1 system's sub in a corner is to get little boost.
I'd get a different result using a different enclosure too. Doing it in the open isn't how you use car audio enclosures, and that would take the intrigue out of the video!
EMF Audio - I am curious about what results you would get in my savana 3500 cargo van.
I guess the only variable that can't be helped is the extra airspace taken up with a duplicate box. That would also come into play because of shrinking cabin airspace.
The only quantifiable variable, yes. There are acoustic variables which is what I'm running into in this test.
There’s a great video with Exo and Showtimespl talking about this and other myths. It makes sense that the additional box would offset the airspace less in a larger car or home theatre. It’s cool to see it proven
In the late 80's to mid 90's when I competed in car audio. The school of thought was you gain 1db by doubling amp power with proper electrical. Reps from MTX, Rockford, Alpine, Orion, etc. I spoke to agreed. Nice to finaly see an SPL test on it though.
That's more of a way of under promising and over delivering. The whole 3 dB thing is documented in books in the 1960's, and it can hold true.
I always heard 3
You are playing the box at resonance. So the second box not playing is resonating just like it would usually, but it is acting as a Helmholtz resonator bass trap since it isnt being driven. Same thing you would do in a home or venue to kill standing waves.
Box placement can always be a prick. I have a couple 12" type R's in a vented enclosure and though typically you would gain db facing the port to the drivers side rear corner or in the area, I lost around 4 db, so it's facing the rear seat where they're at a modest 143 on 1.3k watts. Like youve said in your other vids. No way to know till you experiment n find out what works best for you
Thanks for doing this test Sean, you saved me time & effort as i had planned to test this theory for myself since only gaining 1.2 db after adding another sub. Interesting results you got, i also found my peak frequency changed a lot however i'm using 6th order.
If you're adding subs into the same airspace that is shared that will DEFINITELY change peaks, and you'd never get theoretical gains.
what about displacement ur changing the dynamic of airflow/ pressure
Double Speakers +3db is right but the Power per Speaker has to be the same as before... not half!
No that would be double cone and double power.
If the same power per speaker was applied that would also be doubling power, yielding another 3 dB, which should be a 6 dB gain in theory.
@@EMFAudio no why? The efficenci ist not improved. So why 6db? I only know doubling speakers in the same amp bring's 3db. Instant of 600w now the amp makes 1000w. Doubling Power should also bring 3db but the internal loses are exponentiel so ist not.
Great video. Ahhhhhh, the mystery of car audio.
This needs to be done in a free air environment. When the boxes are in the car, the waves have to conform to the area they are placed in. And vehicle pannels absorb energy. And its not a set amount of energy. The more power you throw at those subs, the more energy those panels absorb. Its like taxes. The more you make, the more they take.
Funny thing about car audio, the application is in a car. What it does outside of the application doesn't matter. That's the point of the video.
I wonder if a box with no port or sub in it, just a 'block' taking up volume would have zero effect or would it also hurt output...
Perhaps we shall find out
This is what I wanted to know!thank you!
And the whole doubling the power or cone area to gain double the aucustic output (3db) there are always exceptions to the rule it tends to be aimed more towards higher power and larhlfer come areas to start with like 2 12s with 1krms to the pair doubling the power will usually get you that 3 db it's not really aimed at 2 8s with a hundred watts
Not to mention the enclosures were wrong
adding that second box makes the hatch smaller so id reckon that would change your peak freq? maybe thats why it got quieter
Car volume is car volume, doesn't matter where it is. A body takes up more volume than a 1 cu. ft box.
The Box that is not playing maybe acts as a Helmholtz Resonator. Boxes without Drivers are used in Rooms for Sound correction to damp too loud Bass frequencies.
Correct! It CAN, at times and some frequencies, act as a booster, but most of the times a sub box is an absorbing resonator.
It's nutz how crucial placement is. I have had 1 1500w skar in a 2.6 cu ft box that made more spl than 2 750 watt alpines. I am extremely limited where I can keep my box due to having 5 toolbox for work, in a freaking camry but when the weekend comes and I have time I move the skar back in and place it where I can't place the alpines and suddenly 3k watts sounds like 3k watts. Thanks for the excellent information I seem to understand the way you explain thing better than some others
Something worth noting, the power rating on a sub IS NOT an indication of how loud it can be, or a comparison to another sub in any form of performance.
@@EMFAudio def agree, ive got alot to learn but that much I do know. But placing the box where I cant other days def makes the biggest difference in the subs I do have. Hope you get the part 2 of the new rockville sub up, the anticipation is a bitch
A pretty big difference between those two set ups is the T/S parameters. Don't ask me to explain them because that's beyond me at the moment, but I do know that they are literally everything when it comes to how a woofer will play and what kind of enclosure it will be best in
Stack the boxs, on top of each other, linear excursion/gravity/sound waves work against each other,your basically gonna bounce sound waves off the gravity. Also you should do a video of when you need to phase shift / reverse polarity on sub woofers
I tried that, it lost just as much, almost to the tenth at every power level. Sound waves are not affected by gravity.
The 3db rule was originally stated when 100watts was about the limit it's a hold over from the days of tube amps, another thing to think of is this math was based on a flat response sealed enclosure, in a free open environment at 1 meter from the cone, Hexibase please chime in. Also a i free cone with a tuned enclosure will actually become a bass trap absorbing the pressure wave rather then adding to it.. on top of that you have problems with time delay
The double power gain 3db or double cone gain 3db. Is measured at 1 meter directly in front of the cone area. Not with car audio spl measurements
Sean, I would say that adding the 2nd box is killing wave flow and also reducing cabin space causing freq to change therefore giving you in correct results as you should have found the new cabin peak with 2nd sub.
Also dropping to low load on amp affects the efficacy of amplifier, lower load is more voltage drop, if you had a power supply hooked up so you had no drop at all you may have seen bigger gains by adding the 2nd sub.
Also please redo the test of 1 forward 1 backwards but have them wired in phase and see what results you get. I think the result was down due to phase cancellation so would be interesting to see.
Awesome video content man 👍 love real in car testing vs bench testing :)
The cabin volume would have changed by 1 cu. ft. Frequency did not change, but even if it did and wasn't tested, there wouldn't be 4 dB difference in even a 5 hz change. Remember, I'm using a 15,000 watt amp on an electrical system suited for that 15,000 watts. There is ZERO voltage drop for making even 600 watts. You might be shocked to find amp efficiency is the same at those impedances and low power levels. Typically amp efficiency doesn't start to really drop till below rated impedance.
Having both subs facing opposite ways and wired to the same phase would result in excess of 10 dB loss. Even in a properly working setup you lose over 10 dB.
@@EMFAudio This so fundamentally wrong! Two different subwoofers whether in a sealed or vented enclosure should always be wired in phase. A subwoofer doesn't care which way it faces. As long as both cones are wired in phase they push out at the same exact time pressurizing the cabin at the same time. The fact that you wired them out of phase because of the direction of the box makes me doubt everything you have ever said as this is such a simple and fundamental subwoofer principal!
I have metered 3db with dubble cone area and dubble the power.... your metering is right , i have seen the same effects but nice video 😊👍 greetings from Germany... iam the guy with the 152,9 Dezibel home system 😁👍
i lost my mind after the 15th ad
Do you think the other sub sitting there not hooked up is still vibrating because of the sub playing causing an noise cancellation effect like active noise cancellation and was dampening the noise causing a loss in Dbs. Just a thought.
I have fired 4 8 inch subs into an empty 4 8 inch sub box directly opposing one another and it sounded finominal.but that was in the living room floor during testing ,I have yet to place it in the car yet.
Car dynamics are very different from room dynamics.
@@EMFAudio so true.
Wow I have not seen box placement matter that much just moving it over a few inches has drastic results Your crx has crazy standing waves , that’s got to be why it gets so loud at your resonant frequency, very interesting video , do another video when you think you have it figured out 👍🏻
I'll definitely be doing another box that is very different, but I've got an idea for another video in tackling this scenario I'm going to work on and see if my idea works.
The box and sub setting by the other without playing is acting like a shock absorber when the one sub hits the other moves in the opposite direction because of the pressure and lowers the pressure overall if it did not have the box and was just the sub this would not happen it’s the box and it’s tuning that’s actually doing it
You should redo this, again with two boxes, but the second box is for two subs. Both subs playing in the same enclosure. Guess you need three drivers if you don't want to switch one driver around the enclosures.
The other box propably changed your cabins resonant frequency.
It didn't, I checked.
@@EMFAudio very intresting.
sounds like the cabin pressure blues!
It might have something to do with the sound waves. out of phase. interference. Also, since the other sub is so close to the one running, it will absorb some energy and if it moves it will produce electrical current
It can't produce electrical current if it's not connected.
@@EMFAudio It will still produce the current, it just isn't connected, so it doesn't flow. i would imagine that if it is connected, then it would be pushing power back into the amp, just like they do when driving them, thus damping factor. I'm just throwing stuff out there.
I lean more towards the placement next to the other one was causing some sort of interference, esp.depending on where the meter was located.
@@RobHTech I'm not sure you realize this, but current is flow hence the name. A dead circuit as in your example will never have current.
@@beardedforlife3740 I was referring to a speaker producing electricity when moved. He said it was disconnected, so that rules that out.
--So, I'm not sure if you know that a speaker can move when current is applied, or it can produce electricity when it is moved.
So sitting next to the active sub, the "Dead" sub can pick up the vibrations and thus produce electricity. But, in his case, he completely disconnected it.
The one that wasn't being tested was absorbing the energy of the other if sub was removed but box stayed then the loss wouldn't b as great if at all the moving parts make loss of pressure
You didn't watch the whole video, did you?
@@EMFAudio yes I did he has the sub in the box thats not being powered still in the enclosure
I'm probably wrong, but I thought the 3dB rule was if you doubled your woofer AND power...not one or the other
You are wrong, both should do it, which also means doing both adds both.
@@EMFAudio cool. I misunderstood the theory for years then 😬
But the 3dB rule still holds true, though only for free space not a car cabin.
Was the second box soaking up the pressure via the unplugged sub vibrating? Somewhat like an ill fit passive radiator? I would like to see the same test done with a box of the same size but completely sealed without a subwoofer.
Passive radiators INCREASE output. I've tested it without the sub installed and it still loses.
@@EMFAudio Huh!!! A passive radiator in another unplugged box increases output??? Maybe you found a "free energy" device lol. But on a serious note that would be like saying flex on a vehicles exterior increases output, just not true. I do agree a passive radiator will increase output on an active properly tuned enclosure, just not on an inactive one. I call BS.
So as mentioned the inactive sub is a perfectly tuned "anti-sub" where the sub and port match the driven one. turning a sub around in a contained box does not mean you reverse polarity; sharing a box yes, but the wavelengths are greater that the metre or so that the drivers are apart. 30 Hz is around 35m wavelength I think so you now got a pair of subs almost perfectly out of phase = big loss.
If you have 2 subs, reverse the polarity on 1 of them and get back to me. Play any frequency.
When you were playing only one sub, the other sub seemed to be moving as well, I presume it's absorbing some of the pressure inside the vehicle.
That's what I've found to be true. The sub that doesn't play still moves and can cause cancellation at certain frequencies, or can help your # at other frequencies.
That is true, but I've never seen an instance where that had much effect. I have actually seen cases where 1 sub being disconnected in a box was louder than it not being in it and hole plugged because it was acting as a passive radiator.
EMF Audio yeah, there is more stuff going on there. Placing the other box may have changed the standing frequency modes inside the vehicle, which could have created destructive interference right where you put the SPL sensor. There’s so many variables inside a car that it’s difficult to isolate the effects. These theoretical rules of gaining 3db with double the cone area or power, consider an ideal environment with no standing waves, no phase issues, no temperature rise in the coil, once you factor in all these other variables you can end up with a totally different result
@@__julio__ Nicely said
Could it be changing the cabins re frequency
It didn't, but if it did, it wouldn't be more than 1-2 hz, which wouldn't cause losses of that magnitude.
Hey Sean do you think it would have the same outcome if it was in a fourth order bandpass blowthru? The reason I ask is I've been wanting to go from 2 Sundown sa12's to four of them in my truck which has a 4th order bandpass blowthru. Also any advice or tips on how to make it move more air I usually run a 2:1 ratio. Keep up the good work and info coming 🤙
Once the box changes, everything changes. I plan on doing a different box with common airspace and positioning to do further testing.
u should try it again with closed enclosure, i think that would make some difference. i think that, that air from the ported enclosure is going back to that non connected sub enclosure cause its still in the same air space (car) and that why non connected sub is moving too. ill bet that u gonna get different data :)
Changing enclosures in any instance would give a different result, which also helps prove the point.
3db rule is for calculated power based on constant voltage applied to a nominal impedance. Bl decreases when excursion increases and impedance decreases when Bl decreases for any fixed frequency. You literally see it decreas in the video as power increases, so less voltage was applied than the required level for a nominal impedance. That is also why your results were incorrect in your enclosure design software video, none of them use constant power to plot the graphs, instead they calculate voltage from the power level you specify based on nominal impedance (bass box6 pro) or dc resistance (winisd) for the ones we all love to use.
BL only decreases when the coil is leaving the gap. It's possible to have a completely flat BL curve, especially with underhung designs. Impedance rise is reduced as BL decreases, but it won't go below DCR. There are instances tested in that car, with that enclosure, where theoretical gains did happen up till mechanical limits. The enclosure design software being wrong I've done videos on, which showed even more issues than what you're describing.
@@EMFAudio The transfer function of the car is what was missing from those programs, it is fairly constant within a few inches of the measured space, and can easily be accounted for in winisd pro by adding a linkwitz transform to match the measured transfer function of the car for a specific location or just adjusting the graph for programs that are basic. Port compression and power compression can also be accounted for to maintain reliable simulation at all power levels. Your test method is flawed because you're keeping a variable constant (power) and varying what is supposed to be constant (voltage), which skews the results negatively. With your method a heated coil would not show power compression in your tests.
@@jadebrown7259 Nicely said. Car transfer function is a linkwitz? Wow didn't know that!
Your second box is absorbing some of the air pressure
It's made from the same wood as the first one.
It’s suspension. Driver
I was just wondering, what will happen trying them in a mono box. Would your +3db theory be relevant with this application as opposed to individual boxes
I have tried another box with a common chamber and scaled, but placement of subs and port was different. It didn't lose as much but still didn't gain near theoretical. I will be building another box yet to test some things.
Great question...
I agree that sub and port placement may greatly affect this theory as I noticed mainly the two individual boxes were extremely close to each other. If putting them on opposite sides of the vehicle change you db outcome? I believe the you lost output because of cancelation, and when you played it individual when the both enclosure were inside the vehicle one worked as a passive radiator, again all theoretical... I did have the same issue with with a loss of output when doubling subs, same individual yet identical box. Could change in vehicle internal cubic could affect this?
a mono box is a single box. each speaker was in it's own box. putting both speakers in the same box, even in it's own sealed chamber, changes the total volume, if the box itself was the same dimensions as both individual box. the speakers, he said at the beginning of the video was bigger then the speaker needed. if he used a box specifically with the airspace needed for those speakers, the decibels would have most likely been higher.
as everyone should know, the space behind a speaker, in a sealed box, is never changing. the speaker compresses the air behind it and that force is used to push the speaker back out. pressure created in a sealed space is pressure received on all parts of the sealed space. what the speaker pushes into the box, the speaker receives in return from the box.
ported boxes are different because the pressure the speakers put into the box is released allowing the speaker to actually travel further then in a sealed box. the speaker in a ported box actually works less then a speaker in a sealed box. the speaker is not fighting pressure in a ported box like it does in a sealed box. if the box is built for the air space a speaker needs then it does not need to be ported. if you need more airspace then you have space for a box, you would need a ported box.
having multiple subs in a single enclosure all sharing airspace the subs will behave more like , 1 large sub . Compare to each sub having it's own airspace eaach sub will operate singularly which for sound quality and quick bass response would be better than Multiple subs all sharing same airspace the subs are going to operate like one large sub since eaxhs sub can influence the other subs say you are running. 1 amp to drive all subs not every sub is. Going to have same exact resistance even if they are all d4 ohm subs each coil is going to be slightly different even on 1 sub one coil might be 3.8 And other 4.2.also so even though it's a . Small difference. Each sub is going to get. Either slightly more or less power also how the sub is put together one subs spider might be just a lil stiffer ect ect. So again for SPL you will need to try n test different setups although almost no one is running a. Sealed enc. For SPL. These days it's now usually. A 4 or 6th order.or a big vented enclosure.
This is to become crazy. My brain is burning. How can you loose so much if you add more power and subs😠 then why expending
No. Loss happens only when the added sub sits there with no input power. If you pay close attention, you can see the inactive sub is moving as well as the active one. Where did that moving energy come from? The box's not powered! Well it gets its energy from the air moving around it. That's the sound energy! Our precious energy goes to the other speaker and dissipates as heat in the suspension and box. Actually, that's how modern "helmholtz" absorbers work in the acoustic rooms and recording studios.
The unused box just sitting there interrupts the sound waves of the working sub and therefore results in weaker readings at the meter? That’s how my brain works anyways 🤷♂️ kind of like in my car when I take the baby seat out of the back and it’s louder at the meter. Less things for the waves to bounce off of ASSUMING the more they bounce the weaker they get exponentially. If I fold the back seats down it’s even louder. The biggest gains and losses I’ve noticed tho have been a result of moving my box as you did with yours. A few DBs difference between subs up port back and port up subs back. Haven’t tried subs front port up because my amp rack is right there in the line of fire behind the back seat. Oh! I should mention this is in a Ford Edge with full glass panoramic moonroof....my first edge with full cloth roof and no glass was 2dB quieter, same equipment. That’s what started my theory on “it’s what the waves bounce off of (or don’t) that matters.” Maybe I’m crazy, but the meter doesn’t lie sitting there in the passenger kick. Now, if I crack each front window 6” versus completely shut and put it on the dash it’s even louder. Go figure.
Opening windows and being louder is most cars. Glass roof vs metal roof has to do with roof strength. You have less energy lost to "flex" so it's louder.
EMF Audio thanks for the response! Keep up the good work! 👍🏻 it’s an interesting sport that’s for sure lol. Question though, I’m running 2 American Bass HD 12s on a sundown svc4k, singer alt and so on....would the ban hammer be an upgrade in loudness/deep bass? Obviously you make them so you’re biased, but just curious how much difference a change like that could make given all other components stay the same...ported box is 5 cubes net tuned to 32.
audiopipe would be cool to see on the website
You are clearly losing wave energy somewhere. Maybe wave cancelation? Also that box might be too efficient where you are running into the subs mechanical limits very early. 140 at 100w from an 8 is very efficient.
Agreed that the sub might be getting near its mecganical non-linearity, but here's an even bigger loss happening in the rattling parts elsewhere in the cabin and even in the garage. Where do you think those rattling parts get their energy from? Hahaha thank me later😉
I suspect there is an out of phase resonance happening in the enclosure of the sub that isn't playing. The top level power is definitely running out of mechanical, which was also part of the point of the video.
Crx has strange characteristics, I managed to do 153.7 street B legal with a bad agm battery. Moving a side tray can cost you .3 db.
There are some very finicky things with those, down to visor position. One setup I had years ago there was a 1 dB difference in passenger seat position.
How close r we to the release of the v2 hammers. I like to start looking around for a amp, wich amp u recomd for them thats going to pushing them to the limit. Those cone size make any drifrence like mega sorround vs regular cone
You know I'm not going to give a date, but we're working on getting higher end amps and bigger ones. Of what we have right now you'd be limited to an amp per sub.
So how noticeable was doubling power?
And then adding the other sub? Which was more noticeable?
How about not running them phased 180 ?
Both, or single? I did single.
Maybe people who made all these theories aren't so smart. Or maybe these theories only apply in a Anechoic chamber.
Theories only apply in perfection conditions.
And, if you wanna be reeeeeeally smart, you'll notice that a 2-times increase does NOT equate to a 3dB, but a 3.01dB increase in gains hahaha😂😂😂
Loading the sub and box not playing beside it in the given air spacce in cabin could cause compression loading in that specific location although I admit that is absolutely weird
Very interesting video.
The changing phase thing... I can't understand why you'd need to change phase because you changed sub direction. Soundwaves in the sub range are omnidirectional. Doesn't matter which direction you face the subs, the soundwaves will start off and end up at the same point in the spectrum as the other sub, regardless of direction, changes in tuning frequency between the two boxes notwithstanding, which wouldn't affect phase anyways. Changing phase shouldn't help, it would hurt. Which it seems it did. Just walk me through it.
When a waveform is made from a speaker, the speaker either moves forward or backward from the neutral position first. The phase determines that. If 2 speakers are playing the same thing side by side, if one moves forward and one moves backward they are 180 degrees out of phase. The frequency being played won't matter because it will always be 180 degrees out of phase. In this case I turned the box around 180 degrees, so the phase has to be changed 180 degrees to make the cones move the same direction at the same time. Had I not reversed the phase, there would have been much greater losses, in excess of 10 dB, likely close to 15-20 dB. This can be displayed in a common enclosure, separate enclosures, mids, subs, anything. If you have 2 subs, reverse the phase on 1 of them and take a listen. It will suddenly make sense.
@@EMFAudio Phase doesn't have anything to do with direction. Phase is a wiring/electrical issue, not a directional issue. 2 speakers are in or out of phase regardless of which direction they're facing. They will, as you put it, start moving in the same direction from neutral regardless of which direction they're facing. What I saw in the video was possibly cancellation, because when a sub fires into the trunk, the trunk becomes a secondary chamber with its own tuning frequency, like a 4th order. Which would change the length of the sound wave. Again, sub waves are omnidirectional and phase is determined by starting point of wavefront. If you had inverted one of the subs, that sub would have to change phase as it would be 180 degrees out. But just a change of direction? I legit don't think so. Not the experience I've had. But I'll check with some other installers and confirm.
Man, do not connect the second sub reversed polarity when flipped, at 50hz length of the wave is still almost 7m, thus they still act more like one unit. Probably got confused when there are two speakers in one box and one flipped and reversed. Nice videos :) subscribed
Sometimes you try things both ways and use the better result for videos.
If you havent allready, check out ZAPCOs website. They have some really nice equiptment! Very high end stuff.
Looking for the video where you double power and cone area. Also would love to see doubling cone area in the same enclosure. Obviously we can conclude that there are no hard and fast rules for linear db gains. Each install requires testing and twerking.b
Doubling the cone area in the same volume means to physically fit it will likely be way too small or way too big, or both.
Try using a sign wave to eliminate phase cancellations and reduce the power
Sine waves are the only things being played in this entire video.
@@EMFAudio Sorry, it don't sound it. Might voice coil heating be a confounding variable?
I really didn't expect that! Bass+Car=Weird thing happening i guess😅
From my experience the 3DB rule comes into play when you Start getting Closer to 150DB. The Pressure is increasing and the Cabin Area is Decreasing. You have to Start Doubling the Power and Cone Area as well as increasing your Electrical system. Once you get above 150DB it really Starts getting Difficult to go up 3 DB. Going from 150DB to 153DB gets a lot Harder.
The Tuning Comes into Play as well. Having a Box tuned at 45Htz will prob hit a higher SPL that a Box tuned at 32htz. However, In my opinion the 32htz will sound better. Much deeper Bass. To get to the same SPL with 32htz will take more power than the 45htz box. It also depends on how and where they set the Meter at for the SPL reading. If the Windows are opened are closed. I could go on for Days. I've been in Car Audio for 20 years.
Just remember their are a lot of situations that come into play. Get a Car that has a True Hatchback like a old Acura Integra or Honda CRX. Shid, the CRX back in the Day use to pound like Crazy. The car was the Sub box.
Did I waste money buying another sub? If I’m only gaining 1db?
That depends what your goals are. In terms of competition, 1 dB is likely money well spent.
could cancellation happen because of the unpowered sub acting as a passive radiator kinda idk?????
Passive radiators AMPLIFY the output.
@@EMFAudio
Yes I know they amplify output in same enclosure as live driver but if it's in a different box unpowered. wouldn't that be like a loose door under vibration.
One variable not considered is the room (car, in this case). I wonder if the results would agree with the theory if done in an open space? In the car, it would be interesting to see what happens if you moved them further away from each other.
I can say this very car has had instances where doubling gained 3 in power, but cone area I can't recall if it ever has. The environment is obviously a factor when you see what happened with the box just sitting there. That's an environmental change.
Cap the port of the box not in use
Hey I had a question is a 3 cubic subwoofer box to big for a single 12 massive hippo and btw it’s ported thanks
Definitely.
Damm alright now to trow out the ported box I just build and back to the drawing board 😅😂
would shorting the voice coil of the unused sub help in making sure that it does not act as a passive radiator and therefor avoid cancellation?
Shorting would change inductance, it wouldn't keep it from moving at all.
Don't slay me of you already have covered this topic. Will EMF or have you thought about making a 6.5 subwoofer or something similar to those currently out there already thanks. BTW great vids ✊
No intentions of making a 6.5" unless we end up doing an OEM job with one that ends up being something we could take to market for ourselves.
did you connect the second speaker on opposite terminals or were they the same polarity?
There is only 1 set of terminals. Polarity was the same when facing forward, 1 facing back had phase reversed.
@@EMFAudio i have been playing with the phase with my system in my truck and i did notice it got louder. both subs are single voice coil in parallel at the single speaker terminal at the box and hooked up to class d mono channel amp.
both subs face upward and the port faces upward between the speakers. my 6.5 mids face toward each other through the sub sound waves.
Let's see some test with that new equipment I seen on your website.
Then watch this video?
@@EMFAudio how about test some mb quart ar hifonics amps or those components I seen. Ant seen anything on mb quart in a long time.
That was the theory when I started in car audio back in the early 90's., or atleast how I remember it.
It still is today, it's science!
Theory vs Reality.....
Fight....
Reality Wins!
Physics is strange.
Flip the phase on the dual sub forward and back firing.....you lost dB on that due to the back firing sub being out of phase.
Why?
The air slug in the port itself is vibrating exactly like a cone that moves in perfect time with the driver in its enclosure.
You mean where I did reverse the polarity and specifically stated why I was doing that at 11:43 ?
@@EMFAudio no. Click the "read more" below the rhetorical question I posed of "why?". But I'll repeat it here again.
Reversing the polarity severely lowered your SPL and I correctly predicted it as well.
The air slug in the port exactly duplicates the surface of a driver (and is IN PHASE with said driver that shares its box) so long as the material being played is above the system Fb (port tuning.) So you now have the output of the port directly interfering with the output of the driver next to it. Remember that ports flip the backwave off of the transducer by 180* (roughly)....
Flip the phase and watch the score go up at least 1.5dB if not 2.5dB
So basically you were incorrect in reversing the polarity of said sub. Put it back in phase and watch the score jump up.
I think it just shows how much you have that car dialed in for the enclosures you are best with. Sound waves... move the enclosure a butt hair to the right, gain a tenth! Move it two butt hairs, lose a db🤬 and some hair off your a$$
Thank goodness I’m shaved.
I actually did try moving one of the boxes several inches forward and backward to see if there would be a massive shift and there was 0.1 difference. But, in regards to your thought process, I metered in the middle of the car at the line of the B pillar and it's 10 dB quieter than the windshield and 11 dB quieter than the rear of the car.
EMF Audiothanks for the reply. test test test is how we gain on the meter! 😬. I wish I had a dedicated area at my place I could test and it not travel so much. Garage is attached to part of the house , anywhere else it carries to the neighbors too much. And my neighbors complain when I come home from ** work at 5pm playing triumph or Eric Clapton with my windows up no subs on. I could only imagine the complaints I’d get if I was burping and testing 🤬🤬🤬🤯🤯
@ *The3rd ERA*
You are going to have to make a complete concrete cinder block garage so no sound escapes outside and you can do all the testing you want.
I test in my detached garage which is better about killing sound than my attached garage because I took some extra measures when I built it. I had a neighbor that moved and he called police on me for hearing a grinder at 7 PM when I had the door open so you can imagine how many times he called about anything else.
Hey bro what's the easiest or safety way to check polarity on a speaker well single voice coil subwoofer? Thanks!
You can use a drill battery or a 9v battery and tap the leads on the battery. Pos to pos, neg to neg. If the cone moves forward polarity is correct. If it moves backwards, polarity is reversed. I say tap the terminals because holding it in place could damage the speaker.
Dude, this just blew my mind. Makes no sense to me
the none playn sub is acting like a bass trap
I have never heard that only doubling cone area or doubling power would net a 3db gain. I have heard that doubling cone area and power at the same time should at least net a 3db gain.
I have also heard that a 3db gain will be twice as loud to the ear but from my experience it takes 6db to be twice as loud to my ear.
Very good video though. I appreciate it.
The theory is doubling power is 3, doubling cone area is 3, doubling both should be 6. In this case, that wasn't the case.
@@EMFAudio 1 sub 100w 141.3db. 2 subs 200w 144.5 dB. That would be 3dB
Similar thoughts as well when 1 woofer was hooked up I was getting the full 100 percent of the power with 2 the power was cut in half between the two.
I would love to see you carry Orion. Can't find anyone that carries Orion.
There might be a reason for that.
@@EMFAudiodon't they make good, if expensive, amps?
@@LexusYachtClub who wants to sell more powerful amps for less money than their own
Yes
Hey Sean, would it have ANYTHING to do with the 2nd box(when not playing) taking up cabin space and changing the cabin gain?
Putting 2 brands in the EMF hat. One is Crescendo and the other is Deaf Bonce. Great vid, weird outcome!
Loss happens only when the added sub sits there with no input power. If you pay close attention, you can see the inactive sub is moving as well as the active one. Where did that moving energy come from? The box's not powered! Well it gets its energy from the air moving around it. That's the sound energy! Our precious energy goes to the other speaker and dissipates as heat in the suspension and box. Actually, that's how modern "helmholtz" absorbers work in the acoustic rooms and recording studios.
.
The fact that the second box takes some space DOES have an effect on changing the tuning frequency of the cabin, but the effect on the SPL is minimal.
There was still a loss when the other sub had power applied. If you consider theoretical gains, if over 2 dB is lost with the box being there and with the sub powered gains 1 dB, that would be a 3 dB gain but 2 dB still lost from placement.
from the looks of it, you are trying to put the same amount of power through one speaker through two speakers. this is effectively dropping the total power output by at most half power. you would have to double the power output to run double the speaker impedance, even if both speakers are wired the exact same. if you wired the speakers in series, you would get the same output as one speaker in two speakers at the same power output because you would effectively be raising the total impedance of both speakers. the reason you got less output from the speakers per power increase is because you raised the total impedance of one speaker by adding the second speaker.
how were these speakers wired? were they in parallel series or in series or in parallel?
changing the total impedance will effect the power output needed by the amp and the output of the speakers.
adding that port to the second speaker, effectively increased the volume of space. volume of space effects the sub sound
testing as you are doing, is a good way to decide which way to place your sub-woofers. however, the placement of the subs does not effect the total output of the speaker. the direction of the speakers does change the decibels of the speaker because of the subsonic waves interfering with each other. you want the waves to be going the same direction to keep those subsonic waves going the same direction. adding the port effects the way those waves behave. everything you change needs to be done to everything within the system. the power output of the amp only really effects the way the sub-woofers act. to get max decibels you need the waves to not interfere with each other or complement each other. it goes the same with your mid-woofers and subs. if the mid-woofers are firing the same direction as you sub-woofers, you will hear less base. if the waves are the same, they will cancel each other out. that is why you want to have an interference setting on your mids and subs. with this interference setting, you will hear more high sub sounds from the mids and more low sub sounds from the subs. this will complement each other because the low lows are from one source and the high lows are from another source.
at 10:30 or so, both speaker boxes look to have the same port on them. however the boxes are in different directions, this is counter productive to how the speakers work. one speaker is pushing air toward the front and one speaker is pushing air toward the back, when those speakers are firing at the same time, one is pushing while the other is essentially pulling, causing lower db's
and it doesn't help that the power output of the amp is not consistent when being turned up.
I'm not sure you understand what's going on here. The impedance where the power happens doesn't matter. If you double power, that would change 2 parameters with 2 subs. Output isn't measured "per speaker", it's displacement and power, no matter how many speakers there are.
The only thing doubling power does in my car is make my car rattle louder and pretty soon all you hear is rattling and no bass. 😑 I always hear the most quality bass at low volumes which I used to always think you need more power for more bass
That sounds like you might just be clipping it.
EMF Audio that’s one possibility but it still sounds like at higher volumes all the parts of the car rattling overpowers the bass so no matter how clean of a signal you got it won’t sound clean until each and every part of the car is reinforced to handle the force of the bass bouncing all around in there
Yes, check for clipping and, do some sound absorption mats like Fatmat. Even cheapest brands'll do quite nicely and they're easy to install.
You doubled the subs but didn’t increase the power, you went up to 600w on one sub but with both subs you still only went to 600w, so instead of one sub getting 600, each is getting 300, I’d say that if you also increased the power after adding another sub it would increase maybe a little more
I doubled power each time I tested, with a single sub and both subs, just not both subs from 1 sub. Yes, if I doubled power per sub it should gain some, because I doubled power from 1 sub also. That theoretically would be 6 dB gain.
Great vid as per usual ...properly strange results though 🤷♂️
What sorcery is this?? O_o
Would there be gain if there's a combination of sealed and ported enclosures (2 sealed 12s and 2 ported 12s; or 2 sealed 12s plus 2 10s ported) in the same system?
That's very hard to predict, but there can definitely be phasing issues, especially if the subs are spaced apart.
One sub is losing energy because the one not playing is a passive radiator with a brake on it...? Harmonic cancellation? Harmonics?
Is there such a thing? Or am I an way tF off?🤷♂️
You're right man. It's moving. And it's getting its energy from the sound wave, and it's dissipating it into heat in the suspension and box. If the wires to the inactive sub were shorted together, even some more energy could be lost as heat in the coil of the inactive speaker!
I've seen cases where there were gains acting as a passive radiator. I think the most likely explanation is the enclosure resonance being out of phase without the sub playing.
Why it was louder after the 180°swap...
open the space between them
Can't, amp is in the way.
Should had put both in, and doubled that power. 400, 800, 1200w to both.
That wouldn't keep a constant, being power. I could have done that in addition but I was more focused on finding a solution to the losses.
Regardless of results still impressive for a 50$ sub👍🤜
Crazy stuff🤔🔊🤔🔊🔊🤔⚡️⚡️🤔