Better Sounding Subwoofer Arrays Part 2 - Sub Arcs, Delay & End-Fire
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- Опубликовано: 24 июл 2024
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00:00 Introduction
00:44 Splayed line of 8 Subs
02:08 Splayed and delayed 8 subs
03:57 Splayed and delayed cardioid subs
05:06 Physical arc of 8 subs
06:57 Physical arc of 8 cardioid subs
08:01 Spaced line of subs arc delay
10:29 delayed arc vs physical arc
12:14 4 subs per side spaced arc
14:38 2 X 2 end-fire array per side
19:11 Conventional + end-fire combo array
24:46 Upcoming in video 3
Cardioid subs bring a tremendous improvement to any system I’ve used. Taming that boom on the stage changes everything. Monitor clarity, artist enjoyment, even IEMs work so much better. I consider them a must have.
Yeah, avoiding sending sound energy to places you dont need it is huge
@@DaveRat Merry Christmas to you Dave! Please apply that wish of kindness to the holiday of your choosing.
Really enjoying this, Dave. Thx for your time and effort.
As usual, another fascinating video from The Master. I’ve been looking forward to this second part and it didn’t disappoint. Awesome information Dave. Thanks for sharing this with us.
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Hey dave! I just found this series and am loving what you put in the first two parts. Eager to eventually see part 3!!
I thought it was up
Great stuff Dave! Once again thanks for sharing the knowledge!!
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Wow, That was so fascinating. It's definitely challenged and changed what I've known or been taught about subwoofer setups and how important the placement is. Thank you for being willing to share this information and knowledge with everyone, Dave.
Awesome Ben!
Excelent video as always,Thanks Dave.
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been a member for years, following you on your adventure forever
Now this is some good content! 👍
The people want bass- they want it flat, and they want it LOUD!
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Very nice Dave from Wellington nz we wish you the family a very merry Christmas thanks brother
Fascinating stuff. I've never really thought about all the things that go on behind the scenes so to say, but I've noticed the effects of a bad setup PA for sure. I don't go to loud venues these days because I try to spare my hearing for the studio, but when I was younger I always looked for the spot with the best sound, and it was usually way in the back, where it wasn't supposed to be.
Cool cool Lasse!
The visuals are the the Rorschach Test of audio spectrums, LOL. This series is so interesting, I'm getting a lot to think about out of this, thanks Dave. :)
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Higher frequencies above the crossover point are typically present - the slope extends outwards at 12dB/octave... maybe 24dB/octave... and rarely 48 or 96dB "brickwall filters", but *even with a filtered signal* harmonic distortion from real loudspeaker drivers will be present several octaves above an input signal, even a sine wave.
Agreed
But at what volume? If that higher frequency sounds coming from the subwoofer are more than 10dB quieter than mains I'd say it should be inaudible.
I believe that assumption is flawed. 10db is percievedbas 1/2 as loud. So if the issues are 10 db down, that would mean about 1/3 of the percieved sound 8s flawed
The freqs are different. Though this example is different, one analogy is to think of a speaker operating at a high level that has a loose dome or slight rubbing of the voice coil or small hole in the cone. Have you ever heard any of those happen?
The speaker may be putting out 100db, 110db or whatever, the air leak or rubbing sound will only be a tiny fraction of the sound created, maybe 30 or more dB quiter than the speaker output yet clearly audible.
Another example is distortion. We look for gear with a fraction of a % of distortion.
Take one speaker and play it at 100 db clean. Place another speaker next to the first speaker and play it 10db down at 90 db with 100% distortion.
Would the speaker playing at 90 db with 100% distortion be inaudible?
Love these sub array videos Dave! Also I loved seeing a photo of Ronnie. I got to work with him in Edmonton AB when he was mixing Bad Religion, and he was teaching some young person sound.. I think the opener was Plague Vendor? Anyway, Ronnie was excellent, and had a million tips that this young person absolutely took for granted. I learned a lot that day. Looking forward to the next sub video!!
Yes! Ronnie is awesome. Can't wait to surf with him soon
This is so interesting. So many standard venue setups fall into these simple problems
Very cool to see these more complex arrays. Would be interesting to see a similar comparison with higher frequencies. Or what works best when going for very high low frequency output, as is common in EDM. Where I'll generally see as many subwoofers as will fit in the room, or on a truck, as many as thirty two 2x18" cabinets stacked two high in larger venues serving 4-8000 people
4 people only need 1 sub 😂
Awesome!!
RGB LED array lights really reveal the issue with arrays : multicolored *shadows*.
The way that synthetic phased arrays with frequency and delay dependent processing work with off-axis radiation and reflective surfaces gets ugly, quickly.
A lack of clarity mounts up quickly, and "chaotic diffraction" can become an influential effect.
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cannot wait for part 3!!!!!!!
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Luv the analysis. For those of us just learning all of this, this is great helpful stuff.
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Thank you.
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Your vid’s are very interesting from a technical perspective. I’d like to see how this can be used in a home environment with multiple subs!
As I said
Sir, I bow
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Great Video.😃👍♥️
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thanks!
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It's quite normal to see dual subwoofers when small bands have purchased a PA-system. And they're more often placed on left and right of the stage under the main speakers.
This causes the power alley effect and the bass in the audience is very uneven.
I have had this habit of ALWAYS building an end-fire cardioid if I have two subwoofers available. I get as much power as I did, but I'm creating way more even response at the audience while also cleaning up the bass from the stage and reducing the reverberation from back and side walls of the venue since the directionality increases.
And with digital mixers of today, that kind of simple PA-processing is easily done so you don't need to have separate processor either.
I think everyone should learn to do this kind of basic stuff even if they have two subwoofers :)
In video 4 you will see how to make those common setups work wonders
@@DaveRat that’s the video I’m waiting for eagerly. Next week?
Happy Holidays…maybe Santa will bring you the 31Hz you’re missing from the set 😂
Vid 3 next week then 4 after that
@@DaveRat Hoping Vid 3 soon?
I thought I released
very nice share
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Absolutely love these videos. Thank you for not being a gate keeper and sharing knowledge from an unbiased perspective! Next week are deploying an arc delay, end fire set up using D&B infra and V-subs. The house has B-22s that I intended to use for the end fire portion, and I'm curious if you have a recommendation on setting the end fire timing in conjunction with the arc'd V-Subs/infra array. Considering the Infras are cardioid, is there a specific frequency (cross over/-3db response?) That you recommend using to set the end fire timing? So far my approach is to deploy the Infras/V sub array with the outter V subs digitally delayed, and then moving that entire array back (digitally) to the B-22's on stage. Curious of your thoughts on this!
Why would you endfire cardioid subs?
I've also had a lot of problems with bass guitar feedback in my floor toms effecting sub frequency feedback.
Yes, me as well
Babe, wake up. New Dave Rat video just dropped.
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Thanks for all your work. This point would be more well-illustrated if the color scheme was flipped in many cases.
Yeah, I could see other color schemes working, like the choices I have in my infrared camera to show temperature.
Like using lower freq colors to show lower level sound, rather than the reverse
But both soundvision and Mapp use this color scheme so it's familiar and I believe the only option.
Awsome video Dave!.. I now wonder what is the impact of the crowd in the bass "diffusion" when 80Hz and up, could the crowd act as a aperiodic subwoofer?. I mean what is the air density in your simulation vs what the crowd does to the average "air" volume? their body mass, cloth.. all that stuff could also contribute to some sort of diffusion and reduce these multi ray patterns and create more "softening" of these?
Yes, there are loads of variables, room reflections, humans, and even temp.
And
Setting up an array that can sound optimal and has the capability to cover the desired area is the starting point you would ideally master before adding in all those other complexities.
This is what we call science ☝️
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Hey Dave, curious what you would think is the optimal setup for 4 Fulcrum 1x21" cardioid subs for medium-sized outdoor shows. I can't seem to figure it out with experimentation. They seem to lazerbeam like crazy in a center arc.
Also if you haven't checked out Fulcrum's products, you should read some of Dave Gunness's white papers. He's been doing some pretty cool boxes that we really love.
Dave is super smart and a friend as well. I worked with him when I consulted for EAW and love chatting in depth with him whenever our paths cross. His designs are very cool.
As far as sup setups, 2 more vids in the series.
And I recommend downloading soundvision and use do some predictions using KS21 or SB18 as the predictions will be close enough to the Fulcrum in the forward field and the Fulcrum will have less sound radiated behind.
Brilliant video Dave! How do you determine the amount of delay to add when making a delay arc array?
Great question. Some software like soundvision has a delay arc calculator built in. Else you can draw a physical arc andeasure the distances and convert them to time
But there are ark delay calculators out there that can be downloaded for free as well
Wonderful video, this has been extremely educational!
Can you confirm that the 4 subs per side spaced arc has no delays on any of the subs?
Correct
Hi Dave, thanks for sharing, was curious if the physical arc of 8 subs could have an End fire sub placed behind at that loud equal distance point you mentioned, would it cut out a lot of the blowback towards the artist?
Dual arcs setup endfire or cardiod work well if you have the depth and space needed. Like part of the Bassnectar array .
Hey Dave, most would probably be interested in setups wich are suitable for small indoor venues where the room itself plays a vital role. Do you plan to make any videos about that?
Hi Dave... scroll @ 6:20 what if you had say three subs sitting behind the area of the arch at 180 phase with the HP roll off around 100Hz? Would make it tolerable on stage, yes? Phase out hot spot using attenuation on these three cubbies. This setup may work with a "cat walk" stage
Modeling that and seeing how it responds would not be to difficult.
Polarity reversed subs can cancel better behind if properly tuned time and level wise and also create issues in the forward coverage areas.
Very interesting video, what Software are you using to simulate the Subs? Thanks
Mapp and/or Soundvision
This is incredibly helpful. I've tried to do most of these in my head and I do NOT have a photographic memory. 🤤 Thx Dave! 🔈🔈🔈
If you can work with stage design, it seems like the physical arc with cardiod subs really wins out. the stage isn't a standard rectangle but the overall sound benefits greatly.
We are on vid 2 of 4, so more to come!
Hi Rat
Great information 👍,
One question, if the case is " 8 subs, and a stage is recorded music, and the liteners area is the same width as the stage and only mounting possibility in the 8 metal bar in the ceiling (going from "over the listener" and "over all the way to the back side or the stage")
It the best solution to get a spread out placement in a straight line and a delay for the sub(4 delays), or is it better to have a 2D arc with no digital delay, or is there any better solution 🤔:-), I have seen this problem in the Nordics stages when it is inside (because of weather)
Sorry for my long question, but I get so excited about this series 😅
Answering that question would require a dive into modelling and predictions. May be worth downloading soundvision and taking a look
@@DaveRat, thanks I will take a look, do you have any link for this? ( :-) )
Could you do a video of how a center cluster end fire array would look in the software with 2 rows of 4 dual 18s in 2 straight lines using those same 8 bass reflex subs?
On the member side I have shared a file with a bunch of sub arrays to compare including endfire and cardioid center sub arrays.
And am doing a multipart series on a a wide variety of arrays and coverage including vertical and interactions between arrays
@@DaveRat Ok, thanks! I will look into that!
What do you flew the mechanical arc above and infront of the stage?
The forward would be good, the rear energy may put a lot of sub toward the ceiling and create undesirable reflections. Unless if you used cardioid subs in the arc. Then the only issue would be sound occupying valuable real estate that is usually best used by the visual related hardware like lights and vid
That's why I like a single sub in my car
Hmmm, when multiple subs are located close to each other (less than 1/4 wavelength of the highest freq they reproduce, they don't have interference issues that are of any importance.
To determine the wavelength of a frequency, divide the speed of sound by the frequency.
The speed of sound is about 1125 feet/second
So for 80hz, it's about 3.5 feet
So subs closer than 3.5 feet will not have any real issues.
In a car, the space is so small that multiple subs are hard to place far enough apart to create issues
@@DaveRat just something I've noticed when switching from dual cabinets to singles. And this is typically a reflex port tuned to 33 hz, so you already have peaky response to deal with.
@@DaveRat another aspect that these simulations do not illustrate is the way the wavefront hits the listener. The initial attack of the bass note gets muddled when using multiple woofers (in my car that is) a single sub allows the initial attack of bass notes to be cleaner and more pronounced in all listening positions. This simulation illustrates how a sustained note would cause null points ...assuming no room reflections... in a car the woofer experiences cabin gain... the point where the volume of air in the car acts as a large box. I'm sure this effect would overcome any phase offset issues caused by using multiple drivers, but I swear I could hear the difference, especially when moving my head around the cabin. A single driver tends to be much cleaner sounding, even if it's not as loud as multiple woofers.
Is there going to be a part three? Please?
There is, I think it's on the member side. I will make it public at some point
It all changes dramatically when you throw a bunch of bodies in front of it. How do you write programs for that?
Depends, bodies impact higher freqs more than lower freqs. For subs, the level drops a bit but coverage does note usually change due to bodies too much. Check out my vid on heat changing sound. That is more of an issue
Dave, great video’s! Keep them up!
But: Isn’t the delayed arc spaced too far apart, which causes the issues? 1/3th wavelength of LPF 80hz is 1,43m. 20m wide / 7 spaces = 2,85m between the subs.
When i deploy this setup i would never space the subs more apart than 1/3th wavelength of the LPF. That way, at least they couple up to the LPF. Of course issues still happen at higher freqs and in my experience when i add too much delay the setup will sound like Dave described.
But when i’m careful with applying delay, i get good results this way.
Note: this only works when i don’t have to cover a very wide field. Then i convert to an L/R (maybe end-fire) setup. Hopefully the next video’s will give even better alternatives!
It's a trade off. Larger spaces will give more control over the coverage width (longer horizontal line) but bigger spaces will lower the highest freq. Is there not predictions of an arc that is not spaced in the vid?
Smaller spaces will exhibit a response and coverage somewhere between big and no spaces
@@DaveRat thanks for the explanation, i fully agree! Yeah there is of course the not spaced arc, and logically a less spaced arc will be somewhere in between like you said.
Thanks a lot! I look forward to your next video’s.
Well you can adjust the cardioid design placing the speakers facing the artists out of phase but only some coming in at certain frequencies where you get the problem like 100 120 Hz and up that should work
I think having the speakers array in the back of the room should sort out that comb effect adjusting your frequency and delay accordingly does your software map that?
That spectrum only maps infinity space is not reflections because that would have a big bearing. Can you not show the returning ripple that's what it needs
Reflections tend to make more issues. Multiple spaces source create more interference patterns and each reflection tends to act like another source.
I will cover cardioid and more in future vids
What's the gap between speakers you usually set up for the conventional+end fire array, 1/4 or 1/2 wave length?
would depend what you wanted to achieve, and at what frequencies. and where
Let's say for eg. 85hz would be the highest freq (xover point). For this Conv + End Fire config do we gap 1m (1/4 wave) or 2m (half wave) in between acoustic centre? Asking about this specific example shown in this vid by Dave.
Use 1/4 wavelength of either the center freq of the bandwidth or 1/4 wavelength of the most prominent or troublesome frequency.
Is the cardioid arc you did the correct image? How is it cardioid?? (obviously the MAPP displays cardioid results though)
I used Meijer cardioid subwoofers that have a cardioid pattern with a rear firing speaker in them
@@DaveRat ahh that makes way more sense ✓ thank you!
If you had double 18s do you have any recommendations for similar effect? Alternate? Double stacks with a cardioid config?
Nice thank you for that, My question is in a smaller set up could you do or achieve similar reactions with single 18" ..
And obviously the energy would not be the same but I think you know what I mean. :)
Did you watch the 1st vid where I start with a single sub?
@@DaveRat I Guess not. Thanks anyways ...
In the first vid I start with a single sub, then one per side, then 4 per side and so on. I think that would explain it better than I can do in a comment thread
As far as single vs dual 18 cab, the response and coverage is pretty close. In vid 4 I will show one array vs 2 and how to deal with interactions.
You asked me if I watched part #1 so I went back and I think you missed what I was asking please read my first Question , " a single 18 " not a single double 18
They will be nearly identical with the single 18 being 3 to 6 db lower in output and the dual 18 a slight bit more beamy.
But all 9n all, a dual 18 and single 18 will del the same up to 100 Hz and not to different above 100
Is there any type of delay/eq that allows you to delay different bands at different times? Kind of like a multi band crossover with a delay on each band summed back into the one output?
That sounds like a total mess waiting to happen to me.
@@djjazzyjeff1232 why? So you could fix the dead spots at different frequencies with different delays?
@@ambroselockerman1115 It just sounds like you'll be chasing your tail forever and have the most complex and sophisticated crap sounding PA in history. Of course, I could be wrong, I'm effectively nobody here, but that's just my initial 2-cents is all.
In video 4 I will show some simple and more complex ways to improve coverage without doing freq dependant delaying of various frequencies.
The goal is to improve coverage without adding too much complexity and without introducing aspects that will degrade fidelity.
@@djjazzyjeff1232 im running eaw tops processed with the ux3600. It has all kinds of filters and delays and sounds amazing with the speakers and amps. Do you know anything about tuning a PA system? Power alleys and dead zones? Have you ever experienced trying to get a bunch of subs arranged in a way the disperse throughout a field of 50,000 people?
What would you do if you had two sizes of subs(15" and 18")?
I would download soundvision for free and use a 15' and 18" sub that make and try and simulate the setup. And run predictions
@@DaveRat Thank you for the reply, I will try it.
Wait - I'm confused @ 10:30 by delayed arc vs. physical arc. If they are time-wise the 'same', why so different?
It's only the same time wise if you're straight in front - if you're right to the side, the physical one the subs arrive at the same time as they would if they were in a straight line or there abouts whereas in the delayed version the one in the middle arrive later
@@stephenevans2518 oh duh - thanks Stephen! 🙂
Yes, from in front the outside subs are late with a delayed arc and physical arc.
From behind the array the outer subs are closer with a physical arc and still later arrival time with a delayed arc. From above, the physical arc is about the same distance to all subs but with a delayed arc, the outer subs are still late
As an audience member, you see subs not pointing at you and think "Crap less sound!" where in reality it is better sound.
Interesting
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I am trying to extrapolate this information for small clubs 250 people and high-end home audio. All very interesting.
In video 4 there will be methods that apply to any pa with stereo subs
Small rooms in home audio work quite differently because of reflections. I played with bass directivity for awhile, but I couldn't get it to help bass response in my room. What actually works for me is multiple subwoofers with delays. But the delays require measurement software like REW to determine once the system is installed, so there is a learning curve. But my results have been excellent!
Hmmm, for home audio, placing a sub or subs in the desired listening positions and then measuring the LF around the room untill you find the desired response, then place the sub or subs there, should work. Since sound is reciprocal.
That is a fairly easy way to find sub placement and account for all the reflections.
That would work for live as well but is impractical
@@DaveRat My pet project is cabinets inspired by the Genelec W371As, so I can't move my subs! The cabinets have a rear ported subwoofer plus front firing sealed subwoofer in the same cabinet. (Also coaxial woofer to make them full range.) Using notch filters on peaks can acheve flat response at the listening position, but adding delays instead of notch filters seems to work better, because response is pretty flat in most of the room.
I don't know precisely how it is working. I suppose I could play a tone and "map" the response in different places to understand it better.
Interesting. Yeah, having 2 low frequency sources in a small or reflective room is an exercise in compromise. But since stereo is already a flawed format that sends similar or identical low frequency sounds to multiple speakers, the issues come with the territory and are inherent.
What happend to part 3?
I have been releasing videos to channel members each week and and a public video each week and with each new public video I pull one public video back to members only. It will come public again at some point
I appreciate that you are talking this topic which is poorly understood. A little explanation of comb filtering for those new to the subject would be helpful. Also some math (not too much of course) showing the physics of the changes per octave would make it more real world and less mystical. Aas to going above the cut off frequency, the cut off is a slope so an octave up would still be outputting some energy, the amount determined by the slope. The mid bass speakers would also be putting out energy as part of their crossover so there is that interaction to understand as well. Finally, depending on the drivers themselves, they could be putting out energy due to second harmonics. Thank you for trying to show a complex issue in a simple way.
On the member side and in the member zoom chats I go into more detail, thank you!
@@DaveRat I under stand the math. It was a suggestion for your subscribers.
Cool cool, yeah, I figure if people want to dive in deeper they can join the member side. Typically the more technical I get, the lower the vid performs on the public side
@@DaveRat I guess I can understand that. You are appealing to the center of the bell curve even if your bell curve is skewed to the technical side.
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Seems like the non cardioid arc would really lend itself to a single cancellation sub at the center point near the stage
Definitely worth modelling if the application has the real estate
Phased arrays are freaky cool technology... but "beam steering" is a dirty word at Cadac's engineering shop.
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I'm curious to know why you mention Cadac; are they branching out from making just desks?
accidentally named it part 1
Thank you and fixed!
What do we learn from this? Go deaf, you won't have to deal with the physics.
Understanding so you can improve. In future vids, I will show cool ways to take coverage to higher levels and get around the physics of interference
Hie Dave, What is the calculation behind, giving delay to the subs are?
I go into detail on that in other sub videos I have done. Basically, for end fire, front sub waits for rear subs, delay is equal to distance between acoustic centers.