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   Home » Horn-Loaded Speakers» Bill Gaw: over 50 years of high-end audio experience and time aligned horns. (70 posts, 4 pages)
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10-30-2025 Post does not mapped to Knowledge Tree
Bill
Kensington, NH
Posts 145
Joined on 03-15-2010

Post #: 61
Post ID: 29427
Reply to: 29425
Answer to Romy
A 30 Hz. Wave Has a 1 meter wavelength. If one takes 12 inches of this insulation and places against the back wall, it should absorb 30-40 percent of a 30-40 Hz. Wave.ii placed about a foot away from the back wall it should absorb at least 50-60% above 30 Hz. And 100% above 90 Hz, if one extrapolates from the diagrams below. That,s obviously theory. But obviously Romy heard something. Whether that is the cause or not of the improvement, all I can say is that nothing else changed in the room to cause the improvement.a Interestingly, I went around the room last night, played a 20 Hz. Up sweep and noticed a definite decrease in the hills and valleys of bass sound volume in the low bass region. So the bass panels definitely are cleaning the low frequency muddying of the back wall reflection. 
(Insert the two diagrams here.)
So experiment. The batts cost $99.00 each for 12 inch thick 2 x 4 feet packages. Line them up 2 to 3 high depending on room dimensions about 1-2 feet from the back wall and kitty-corner in the room corners. Cut out about 80-90% of the front and back cardboard leaving a 3 inch wide band of cardboard for strength to allow absorption of all wavelengths.Make sure you get the one shown below from Amazon or Roxy l as they are half the price of Owens Corning 703, but have almost the same acoustic absorption specs. The typical room may need 7 to 10 of them. My woofers and subs lay against a wall so there are no side reflections of bass, but for those whose speakers are a distance from the wall may get some improvement placing one at the first reflection point of the woofer and subs side walls.
(Insert Amazon picture here) 

10-30-2025 Post does not mapped to Knowledge Tree
Bill
Kensington, NH
Posts 145
Joined on 03-15-2010

Post #: 62
Post ID: 29428
Reply to: 29426
Yes to 400 Hz.
With Romy here, using the Trinnov altitude I could very quickly change crossover points and hear when I began to get horn honk. The woofers began at 47 hz. Which was great as they are supposed to be 50 Hz. Edgar designed. Th mids started honking below 400 so that,s where I placed their crossover. The mids started having a tizziness at about 11,000 Hz. Thus the 10,000 crossover to the Tannoy Red tweeters. Of course my hearing drops off like a stone above 9000 so am unsure whether I can hear the Tannoys. This allows the Vitavox-Edgar mids to take in 90% of the frequency band. With that the Trinnov through experimentation could time align all four of the frequency ranges of the  drivers both physically and electrically to millimeter precision, and then time align all of the 12 channels of speaker for the main listening chair. And to be able to do it sitting in my listening chair not moving a muscle or having to change out resistors or caps, shorten or lengthen inductors Or move speakers by millimeters to time align each to the listening position.So you are correct that for those whose speakers use digital only and probably those who don't mind bastardizing their analog through a to d conversion, dsp is the way to go. I envy Anthony as he starts down the long trail of realizing what the Trinnov will allow him to do. It took me four years of learning how to use the Trinnov to its fullest potential to get to what Romy and I hear now. I just wish I had the will and energy (and funds) to try Wave forming with the Trinnov. Good luck Anthony.Bill
10-30-2025 Post does not mapped to Knowledge Tree
anthony
Posts 371
Joined on 08-18-2014

Post #: 63
Post ID: 29429
Reply to: 29428
Bass traps
Bill, Romy,

This is my solution to the bass, see them on the walls in this photo:


VPR Unskinned.png

Romy in particular, note the all steel construction.  There is some foam in them behind the steel plate and the entire trap is only about 4"-5" wide.  These bass traps do not absorb the mids and highs, in fact they reflect them back into the room...the room in this state sounded terrible...great in the bass but strident elsewhere just like listening in a room of ceramic tiles and glass walls...horrible.

Then you treat the mids and highs back to normality with some simple wood panelling:

VPR Skinned (Large).png



Mids and highs are beautiful again because they are reflected by the panelling, bass has clarity and massive texture because it does not even realise the panelling is there and is handeled by the bass traps.  Those bass traps are effective 30Hz-600Hz, with some effect at 20Hz if the trapdoor to the room is closed. 

Bill, I would be surprised if what you are hearing is NOT due to shorter reverberation times in bass frequencies.  In my experience, the lower in frequency you are able to hold an even decay time in the room, the better the bass/sound.

Regarding the Trinnov, I am yet to really get in and play with it.  The Waveforming feature is exactly the same as a Double Bass Array but you need multiple subs in front of you and behind you for the feature to work, which is fine, but I do not have the room behind me.  I expect that oce properly setup in room Waveforming could be transcendental.

With the bass in my room now well controlled by analogue methods such as these bass traps and subwoofer placement, how the bass is made has more importance.  That sense of envelopment with stereo that is possible when some of the bass is made behind you is a wonderful effect, even though you cannot locate where the bass is coming from, that envelopment happens nonetheless.  Waveforming may eliminate this effect.  Also, being able to use high quality amplifiers and alter the balance/volume of the bass sources within the room may be where the last 10% of bass quality is found, and is where I next intend to investigate.

What is nice though, is that when someone with a lot of audio experience sits in your room and says "I've never heard bass like that"...which has happened to both of us it seems...or when you drive them to question their mantra...which only you have done. 

10-30-2025 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,400
Joined on 05-28-2004

Post #: 64
Post ID: 29430
Reply to: 29429
Place, I did everything to convince you that it is something serious.
Guys, I think you’re missing something important behind all my joking around. What I’m really trying to get people to do is to think deeper—to stop being blinded by data that has no real connection to human sensuality.

Let me pose a question, and you can find the answer for yourself.

Bill has achieved excellent bass with his acoustic treatment. Everything seems fine; everyone nods approvingly. We convince ourselves that the secret lies in how bass reflects off the back wall, and Bill, being ingenious, introduced large panels spaced from the wall to control low frequencies. Wonderful.

But then Bill switches to Auro. Everything else is the same. The system is calibrated so that the transition from stereo to Auro should sound identical. Yet, in the same room, with the same equipment, I personally find the sound less interesting—and more importantly, the new beautiful bass has vanished. It’s back to what he had months ago: dull and uninspired.

Now, there are two possibilities.

The first is that the bass improvement had nothing to do with reflections at all—especially since Auro can simulate virtually any imaginable reflections.

The second is that Bill’s Auro configuration interacts poorly with his new room acoustics and needs to be completely rethought. In that case, the experiment I’d suggest is simple: sit comfortably in the new room, run Auro, turn off the rear channels, and then—slowly, very slowly—dial them in until (if ever) the bass returns to its stereo glory.

If he finds that setting, we must carefully analyze what makes it different from the “recommended” configuration, because that difference might hold the key to understanding what’s really happening.

But my instinct says he won’t find it—and here instinct itself must yield to reason. Rather than filling the void with casual conjecture, we might instead treat this as a small but genuine research question. If identical acoustic conditions produce dramatically different low-frequency behavior depending on the playback algorithm, then something measurable, repeatable, and potentially significant is happening. It deserves the kind of attention we usually reserve for real experiments: controlled variables, documented results, and honest scrutiny.

And if, after all that, the instruments reveal nothing while the ear insists otherwise, then perhaps the mystery lies not in physics but in perception itself—in that delicate, ambiguous frontier where expectation and sound intertwine.

I say this not to dismiss what we hear but to elevate it—to suggest that behind Bill’s missing bass might be a subtle truth about how phase, algorithmic reconstruction, and human sensuality meet in the act of listening. I don’t claim to know what that truth is. But I know it’s worth finding.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-30-2025 Post does not mapped to Knowledge Tree
anthony
Posts 371
Joined on 08-18-2014

Post #: 65
Post ID: 29431
Reply to: 29430
Three possibilities
 Romy the Cat wrote:
 

Bill has achieved excellent bass with his acoustic treatment. Everything seems fine; everyone nods approvingly. We convince ourselves that the secret lies in how bass reflects off the back wall, and Bill, being ingenious, introduced large panels spaced from the wall to control low frequencies. Wonderful.

 


No, Bills sound is better because he is letting the bass note happen for less time in the room than he was before.  It bounces off all the walls all the time...30Hz is 11.5m long wavelength so does not fit in most rooms... and those big new traps mean it is soaked up more quickly.  The position of the traps within the room matters only to the amount of bass frequencies that can be soaked up, and the sound in the room is better because a bass note now only lasts half a second in the room rather than 1 full second like it did before and it is not messing with that next half second of sound.  


 Romy the Cat wrote:
 

But then Bill switches to Auro. Everything else is the same. The system is calibrated so that the transition from stereo to Auro should sound identical. Yet, in the same room, with the same equipment, I personally find the sound less interesting—and more importantly, the new beautiful bass has vanished. It’s back to what he had months ago: dull and uninspired.

 

Bill has additional subwoofers for surround duties...this is a very different circumstance to the stereo playback.


 Romy the Cat wrote:
 

Now, there are two possibilities.

The first is that the bass improvement had nothing to do with reflections at all—especially since Auro can simulate virtually any imaginable reflections.
 


Auro is by definition a delayed response from the immersive speakers, including a delayed bass response, so is totally different to stereo playback and will always sound quite different. 

10-31-2025 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,400
Joined on 05-28-2004

Post #: 66
Post ID: 29432
Reply to: 29431
Please.
Antony, please don’t take this as personal criticism — I offer it with respect, and with a sincere wish to keep our dialogue meaningful. When we speak with absolute confidence, it’s wise to reserve even the smallest margin — perhaps one percent — for the possibility that we might not see the full picture. That single percent is not weakness; it’s the space through which real insight enters.

You reminded me recently of a colleague who once challenged my solution to a complex problem. He declared, with great certainty, that what I proposed was “theoretically impossible,” supported by his thirty years of experience. What he didn’t know was that the same solution had been running successfully in production systems across several companies for nearly a decade. His conclusion wasn’t malicious — it was simply limited by his frame of understanding.

That’s why I must be honest with you. The confidence in your responses feels absolute, but the depth behind them seems only partial. Your argument that shorter reverberation time improves bass, for example, isn’t just oversimplified — it reflects a misunderstanding of the phenomenon itself. I’m not offended by it, but I do recognize when certainty is masking incompleteness.

Please understand — I have no desire to hurt you or diminish you. But I’ve changed. I no longer allow anyone, even unintentionally, to project their version of truth onto me as if it were the only one. I can endure disagreement, even insult; that’s fine. What I cannot accept is being pressed into psychological submission or cornered into reactions that aren’t truly my choice.

It’s important that you know this not as a threat, but as a quiet boundary. I stand very still, and I do not move easily — not out of pride, but because I know exactly where I stand. My suggestion to you is to protect your own equilibrium in this exchange. Approach me, if you wish, not with assertion, but with depth and curiosity. That’s where real dialogue — and mutual respect — can exist.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-31-2025 Post does not mapped to Knowledge Tree
anthony
Posts 371
Joined on 08-18-2014

Post #: 67
Post ID: 29433
Reply to: 29432
Apologies
Romy, reading back at my previous post you are correct, I was not leaving any wriggle room and was talking in absolutes.  I apologise and will try to not post unless I at least have time to reread what I've written, or better yet prepare a post with fleshed out opinion and consideration such as you share.  Not easy to do when I seem to only be able to grab moments for this sort of internet stuff...

But I still don't think I am wrong about the basic premise of the post...it was just too curt in delivery.

Sigh...have to go.
10-31-2025 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,797
Joined on 10-12-2006

Post #: 68
Post ID: 29434
Reply to: 29433
"Incremental Change" and Personal Results
For a long time I have sold the idea that audio changes using different topologies can happen by degrees, and what is unsaid (but pretty much implied) is that different topologies might "overlap" (+/-) in terms of audible results. "Audible Results" is loaded because we are back to the listener, a personal person in a particular situation. As one example, when messing around with speakers that are "close to DPoLS", one might hear big changes from small movements of drivers and/or listener. Not to be simplistic, but perhaps Bill has "stumbled" across a physical combination that delivers good bass in his situation? Sure, it would be nice to have a working theory, but don't we always say, "If you achieve DPoLS, call for the cement mixer."? It may well be, and I have seen/heard it many times, that "the same gear in the same configuration" produces different results. In fact, I would go so far as to say this is usually the case. Bill has worked hard for a long time and used his ears while so doing. God Bless him. I dare anyone to copy him. Meanwhile, I'm not going to bring up Remedios...

Paul S
10-31-2025 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,797
Joined on 10-12-2006

Post #: 69
Post ID: 29435
Reply to: 29434
Why "Should" Auro Bass Sound Like Stereo Bass?
I just realized that I simply don't understand why Bill's Auro or stereo "should" make the same (audible) bass. Why should that be?

Paul S
10-31-2025 Post does not mapped to Knowledge Tree
Bill
Kensington, NH
Posts 145
Joined on 03-15-2010

Post #: 70
Post ID: 29436
Reply to: 29435
It shouldn't and doesn't.
While Romy prefers stereo, I prefer auro 3d surround, especially with Auro recorded music and sacd's. While ambiance r3covery with Auro 3d does not have all of the qualities of the 6 to 12 channel original recordings, it does add significant feel of being in a concert hall where deppnding on wher one is sitting, the ambiance may be 10 to 80 percent of what one is experiencing. 
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