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3A signatures, with time aligned room treatments, vibration control, and DC power supplies galore


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Hey everyone. I'm a proud owner of Vandersteen 3a Signatures, and a previous owner of 2CE's. Pretty much the only speakers Ive ever used, though I own some Yamaha NS-690's, and Kef Concertos.

I have owned my 3A sigs for about 3-4 years now, and its always placement placement placement. I VERY much dread having to go back to placement every couple months, but it usually pays dividends. I have a room that is 130 inches by 190 inches long. the 190 inches opens up into the bedroom with double french doors which I have put in storage to open up the room.

Until last week I have had the speakers out from the back wall almost 70 inches. In such a small room it allowed the backbounces to be 12+ milliseconds from the original sound. I cant say if I just didnt have the right placement before when I tried having them closer to the front wall, or if my treatments were lacking, allowing all kinds of early reflections to completely destroy the sound.

I have always had my speakers 1/5th out from the sidewalls, which is 18" to wall, and 26 to center of speaker with 62" between the inside edges of the speakers. Recently I found a "magic" formula for speaker placement that I stole from a Focal manual. (ALWAYS read the manuals!!! you WILL learn something). It is Bsq = AC, where A > B> C, and those three measurements are distance to sidewall, distance to frontwall, and height to middle of bass driver from floor.

I used the numbers 26" from sidewall, and originally 8.25" to center of rear woofer that covers 26-35hz. That gave me 81.9" out from the front wall. I had some trouble philosophically about whether that number was to the front, middle or back of the speaker, and I certainly picked wrong at first. eventually, after re-reading the speaker manual, I noticed it clearly states the acoustical center of the speaker is the very center of the speaker.

Eventually as everything got more and more dialled in, i realized I had made a critical mistake trying to measure my ear height by myself and my "stick" for measuring was 34", not 36". So after fixing the tilt that I had lived with for years, everything started to magicaly come together, and all the years of work started paying dividends. after that things happened fast. I got a new measurement of 8.75" to the middle of the woofer, which meant 77.257" to the back wall, and this time I knew the exact acoustical center of the speakers. WOW! did that sound good.

So then I had to try the Focal formula on the front Bass driver that covers up to 600hz. That meant 26" and 33.5", and I was to 43.16" from the front wall. (33.5sq = 26 * X) (1122.5 = 26 * 43.16)

This is where Im at today, and damn is it good. I use zero toe in. (or indistinguishable from zero toe in)

I also listen "nearfield". With my speakers 78" from acoustical center to acoustical center, an equalateral triangle places the ears listening position about 66" back from the middle of the speaker, or only 61" from the front of the speakers. This largely helps take the small room effects out and allow the direct to ear sounds to arrive faster than would otherwise be compared to first and early reflections.

 

TUBE TRAPS:

Tube traps are a miracle of engineering. They are powerful and compact and work on pressure differences rather than trying to trap a half wave of bass thats 30 or 40 feet long. The round fiberglass is sealed on both ends and compresssed to the exact right density to have the perfectly optimized air flow resistivity. When the pressure changes in the room, the pressures in the room and inside the tube trap starts to equalize within 2ms. When this happens, air flows through the compressed fiberglass, and is resisted the perfect amount to change into heat as it struggles through the fiberglass. Next, there is a poly-cylindrical diffusion. Its a rounded vinyl like covering under the cloth that has the exact right amount of holes in it to effectively be a 600hz crossover. Over 600hz is diffused back into the room, while under is absorbed.

THis poly-cylindrical diffusion is time and phase aligned and so works wonders time and phase aligned vandersteens. (in my opininon!)

I have also stolen a technique from here, whereby paths to the ear that are short in timing are absorbed or diffused, and long bounce paths are encouraged. This is hard in my small room. So i combined it with another technique mentioned whereby two tube traps are placed with diffusion panels facing each other directly between the speakers. Except I did this on my 8 foot ceiling between the speakers and listening position. The 8 foot ceilings are the 3rd worst first reflections after the sidewall and floor bounces. I tried cieling clouds, but they were not linear, they took off the very top end, but that was all. So tube traps it was. I put two half rounds facing each other, about 2.5 feet apart. The idea being that sound gets trapped and pinballs back and forth until it escapes, some of it getting to the listening position. This gives a nice cathedral like decay where the sound eventually reaching the listener is delayed in time by many many milliseconds. Each bounce of about 2 feet adds 2ms. It also allows for extreme clarity as I have now treated all major first reflections except the floor, and then managed to get some long throw treble as well for a nice decay rate that adds ambiance and depth beautifully.

I have a Chord Qutest DAC. Its real secret sauce is the Watts Transient something filter that uses 50,000 taps to extract more timing information from the music.

My other secret is Stillpoints. They are great. They are the feet on my 3A signatures. I understand this is heresy around here, but with all due respect to Richard, I doubt he ever considered putting putting $2000 worth of footers on a $5700 speaker. (6x $340USD Stillpoints SS ultra). Either way, I paid about $1400 USD used for the speakers, and about$1000 USD used for the footers. and its worth every penny. I have them screwed into the 1-4/20 on one end, with bullet spikes on the other, and then spiked through carpet into the concrete foundation. My speakers are floated. It keeps the colors well, and allows SOOOO much detail to shine through.

Im also a big fan of expensive DC power supplies. I own a sonore optical rendu and optical module deluxe that electrically disconnect the dirty wireless router from my system. Every single piece of equipment is powered through a single cable into the wall. That cable feeds a Balanced Power unit that has a floating ground and keeps the noise from the neighborhood and house out of my system very well.

Im also big into platforms, and own a sandbox style one, a PS audio dual platform/power conditioner, and a HRS platform. I find the effects of taking care of vibrations are stackable, with linear drainage being better than keeping vibrations in, or turning them to heat in a non-linear fashioon,

I currently use a NAD M22 v1 as a power amp. 200W of class D. It is the only piece of equipment in my system that is NOT time and phase aligned because it uses a whole shit tonne of feedback to operate in Class D. But it has some things going for it, like a used pricetag of $1600 USD, real time sensing and adaption to impedence changes to the woofer, and astonishingly low distortion. I also bi-wire, in a true sense, so that the crossover happens at the output terminal of the speakers, and I keep the two wires off the ground with cable risers and the two cables a couple inches apart from each other. Needless to say, I get pretty amazing control of the bass woofers.

For a pre I currently use an Allnic L-4000. Its pretty amazing at 0.016% distortion.

Anyway, its all about the room/speaker/listening position geometry, vibrations, timing, phase, electrical noise, and keeping away early reflections in favor of direct-to-ear speaker path sounds.

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Edited by Ipspam
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On 9/17/2022 at 5:37 PM, Ipspam said:

The round fiberglass is sealed on both ends and compresssed to the exact right density to have the perfectly optimized air flow resistivity. When the pressure changes in the room, the pressures in the room and inside the tube trap starts to equalize within 2ms.

They claim it is a pressure device on their website, but most broad band absorbers are velocity traps.

 

On 9/17/2022 at 5:37 PM, Ipspam said:

 

When this happens, air flows through the compressed fiberglass, and is resisted the perfect amount to change into heat as it struggles through the fiberglass.

Which sounds like a velocity trap.
(it is certainly not a tuned resonator,)

Have you ever used the active bass cancelling systems, which are also usually placed in a corner?

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A lot has been said on this topic, and the Big Boy's hashed it out over on Gearslutz, including Art himself. The funny thing was, even he screwed up the explanation!!! And had to back peddle and give a more concise and relevant explanation later in the thread.

So alas, a mere mortal like myself has no business arguing this stuff. I will first take responsiblity for any misrepresentations I may have made, and point you to the original sourcing for these claims:
Art Noxon explains the Tube Trap, twice, because he simplified it to the point of wrongness the first time.

 

My ignorant understanding is that Active noise cancelling is both slow, and doesn't actually take energy out of the room. It might make pretty plots,  but does not much for "intelligibility", a term as it relates to the ears abilty to hear.

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2 hours ago, Ipspam said:

A lot has been said on this topic, and the Big Boy's hashed it out over on Gearslutz, including Art himself. The funny thing was, even he screwed up the explanation!!! And had to back peddle and give a more concise and relevant explanation later in the thread.

So alas, a mere mortal like myself has no business arguing this stuff. I will first take responsiblity for any misrepresentations I may have made, and point you to the original sourcing for these claims:
Art Noxon explains the Tube Trap, twice, because he simplified it to the point of wrongness the first time.

Thanks that was interesting.

 

2 hours ago, Ipspam said:

 

My ignorant understanding is that Active noise cancelling is both slow, and doesn't actually take energy out of the room. It might make pretty plots,  but does not much for "intelligibility", a term as it relates to the ears abilty to hear.

It would certainly seem to be only useful for the lowest mode frequencies.
But I think they work in the pressure zone of the corner, and decrease the ringing to decay faster.

Do you have waterfall plots of your room?

I am redoing the power supply to 230v, and hooking up the DAC/ADC.
So I, in theory, should be able to do measurements soon.
(I probably need to get another USB cable, I think I left it at the house.)

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I do not have plots. Eventually, but I really enjoy struggling and learning. I also wouldn't bother trying to measure much less EQ bass with a mic. Good luck! There are 8 notes per octave, so 24 notes from 20-160hz. How many plots is that mic gonna pick up? 63 and 125 Hz?  2 samples for 24 notes? Lmao. It's gotta be done by ear in the low end.

 

So yeah, I get it, that's the science, that's how you get to the end game. Except there is no end game, so the slower I go, the more my wallet and ear thanks me.

 

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4 hours ago, GdnrBob said:

I have been reluctant to chime into this thread, but I feel I should do so, now.

@Ipspam,

You have a lot of traps/diffusers/etc in your room.

Did you add them one/two at a time?

I ask only because it seems like a lot of room treatment for a small space.

Bob

Yes,  I have gone from auralex(lol!!!), to fiberglass and other products, and there is something special about tube traps. They are like a black hole, where bloat is sucked in and every note is heard clearly from inside it. The rotatable diffusor is a godsend. So the thing is, each of those traps does something remarkable. Together, more so. The answer could be yes, but I would be hard pressed to get rid of them. They just do so much on so many levels. 

The 6 2" panels of fiberglass are on their way out. They are definitively ruining the sound. But they take care of a worse problem for now, theytackle first reflections because I've learned tube traps are most powerful in pressure zones, so I put them in the pressure zones. My top end suffers, my bottom end excels. A properly placed and rotated tube trap at the side wall first reflection is an amazing black hole that takes away timing signals and let the ear get it direct from the speakers uninterrupted. Tradeoffs. But the short answer is more tube traps, less velocity absorbers.

 

For a more serious answer, this 12 page AES paper thing is pretty good. My room is 2400sq feet. I can't do all the math, but the example used was a guy needed 4.4 traps to reduce Q by 2 in a 2000cubic foot room.. So I'm 1.2x that,  or 5.28 traps.  Then for a listening room,  reduce Q by 3x.

SO if 5.28 traps halve it,  10.56 should reduce by 3, and 15.7 by 4???? A bit confused here. But I think maybe 10.5 gets me that q reduce of 3x. And I have 11. And they aren't all in pressure zones, so I think I have some room still to work.

These things are a real screwball, but I think that 12 pages does a darn good job, I learn lots everytime I read it. Today it's the hint about pure tones to listen for Q. And I happen to have tone generator.

 

https://www.tubetrap.com/bass_traps_articles/room-acoustics.pdf

 

"Conclusion
A listening room does not have an acoustically flat  
response. Most rooms can play better when their  
Q is reduced by a factor of 2 or 3. Room color is  
damped out from the listening ambience. It is the  
Q not the EQ that distinguishes the listening room  
from a standard room. Pink noise is an appropriate  
test signal for EQ settings. Pure tone, not 1/3  
octave sweeps or RT60 are required to monitor the  
room Q."

 

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