Chronicle of room treatments to equip room with the ability to play HT at reference levels

Diffusive blades installed on the front wall!

So, I finally got the stands for my L/R Catalysts yesterday. Pretty much been listening to music since late yesterday evening.

I'm blown away by the difference from before. Admittedly, the extra pair of subs has made a real difference. HST, the combination of absorption and diffusion on the front wall is just magic.

Missus' first words on listening: Wow, the stereo separation! Add more details, increased vocal clarity. My word.

Leaving my speakers in an untreated room would have been a colossal waste of money. The wait for the room treatment hasn't been easy, but it has been totally worth it.
 
So, my other acoustician (my friend and him work together) came home the other day for an evaluation of the system in my room a couple of days back.

Happened again this Sunday. Very brief visit.

Summary: Sounds pretty good. Based on conversation in the room for about a minute. No audio playback.

He recommended corner traps, about a feet and a half deep in all the corners. Perhaps a couple of additional absorbers on the ceiling. Doubling the size of the carpet was suggested, but it's going to be tough to do. All in all, getting pretty close to calling it a wrap as far as the acoustic treatments go once these are done.

He did say that, soundstage depth for stereo, in recordings that didn't have it, is an illusion that can be obtained by manipulating the reflection from the front wall vs direct sound. With the absorption I have on the front wall, this isn't going to be possible for me. We've effectively traded that off for stereo separation, imaging and clarity.

Along with the additional pair of subs, I can safely say that the audio in my room has never sounded better than it does now. The front wall treatment (combination of absorption and diffusion), IMO, has had the biggest impact.
 
Happened again this Sunday. Very brief visit.

Summary: Sounds pretty good. Based on conversation in the room for about a minute. No audio playback.

He recommended corner traps, about a feet and a half deep in all the corners. Perhaps a couple of additional absorbers on the ceiling. Doubling the size of the carpet was suggested, but it's going to be tough to do. All in all, getting pretty close to calling it a wrap as far as the acoustic treatments go once these are done.

He did say that, soundstage depth for stereo, in recordings that didn't have it, is an illusion that can be obtained by manipulating the reflection from the front wall vs direct sound. With the absorption I have on the front wall, this isn't going to be possible for me. We've effectively traded that off for stereo separation, imaging and clarity.

Along with the additional pair of subs, I can safely say that the audio in my room has never sounded better than it does now. The front wall treatment (combination of absorption and diffusion), IMO, has had the biggest impact.
hoping to visit soon. your setup has come a very long way from what I last heard in 2019, if i remember right.
 
hoping to visit soon.

Look forward to it.

your setup has come a very long way from what I last heard in 2019, if i remember right.

You do remember right. December 2019.
IIRC, you’d remarked at that time that my setup had “tremendous potential”. The gap between performance and potential has narrowed considerably since then. Even if I say so myself.
 
Keith Yates is one of the foremost (if not the) HT/stereo room designers around.

Here's a really nice article from him on diffusion: http://keithyates.com/a-matter-of-diffusion/
Wow...that was a lovely enlightening read @liverpool_for_life

Thanks for sharing it :)
I guess Iam a convert now. But sadly won't have the space in a 11x15 ft room with a kids bed to probably get diffusion in, without making it look like a recording studio and not to mention a sound sermon from my better half too :D

But I really need to tackle my room, as it's acoustics are atrocious :D

And no point spending a penny more on the kit, knowing fully well that the villain is still there to kill the improvements :D
 
And no point spending a penny more on the kit, knowing fully well that the villain is still there to kill the improvements :D

Very happy to hear this. You only hear what your room allows you to hear. Fix the room and you'll get much closer to the potential of your speakers. Prepare to be blown away!
 
@liverpool_for_life - I have a question in one of the photos you have the fronts on top of the subs, I had a similar config on my enbees where the towers stood on top of the subs, but anyone who looked at that always said it is a horrible idea - vibrations from the sub interfere with the sound etc etc. Is that true?

Why I ask is - I love the idea of BS with Subs rather than FS with subs (somehow prefer it), so if keeping the BS on top of the sub is an option, I have the option to add the second sub to the config, if I want to.
 
@liverpool_for_life - I have a question in one of the photos you have the fronts on top of the subs, I had a similar config on my enbees where the towers stood on top of the subs, but anyone who looked at that always said it is a horrible idea - vibrations from the sub interfere with the sound etc etc. Is that true?

Yes. Not just vibrations from the sub being detrimental to the mains' SQ, but more importantly, from the perspective of safety (don't want your mains in danger of toppling).

The sub I had the mains on though (Seaton Submersive HP) have dual opposed 15 in drivers essentially rendering the cabinet completely inert. So, no issues wrt safety.

Here's a (cool) video that demonstrates the inertness of the cabinet with a coin atop the Submersive playing at Reference Level:

Of course, I ran into physics and learnt that the best place for the subs is unlikely to be the best place for the mains. So, I moved the front subs to 1/4 width from each side wall (to help with minimizing the effect of width modes) and put my mains on stands.
 
[...]HST, the combination of absorption and diffusion on the front wall is just magic.

What a difference long-term listening makes. As installed, the diffusive blades were a mistake. It became clear when we started watching movies again in real earnest during kiddos' summer vacation last year that I could no longer play at reference levels without complaints about the sound being too loud. A 5-7 dB reduction was pretty much called for in order for family to be okay with perceived loudness. Naturally, this lead to a significant decrease in impact during movies and angst set in.

I also ran into another issue wherein Atmos effects from the front ceilings seemed to blend in with the front soundstage, making it taller but restricted to around the screen area. This took away from the immersion that Atmos promises.

After examination of potential factors that might be causing this, and pretty much eliminating all of them, it became clear that the diffusive blades could explain what we were hearing and so they needed to be moved out of the way. As an aside, a fellow FM who visited my home and is probably the best subjective listener that I've had walk through my doors, did make a remark about how the blades might be affecting the sound but I wasn't smart enough to tie it to the problems I was noticing. I remain eternally grateful for his feedback.

The diffusive blades were removed and that helped with the issue of SPL levels a bit, although I still couldn't get to reference. This was a massive bother for me as one of the reasons I paid up for the speakers that I purchased was the ability to cleanly hit reference levels in my room. The last five odd dBs to reference just takes things up to another level. If I couldn't hit reference with the front wall being treated with so much of absorption (16 ft wide and 7 ft tall worth of panel coverage), something was still amiss.

It was time to look at the actual absorption material. Bonded Acetate Fibre (BAF), in my case. Could neither find (nor get, when asked) actual absorption coefficient data for this. Reason seemed to suggest that this was the issue, so I decided to check out absorption material from Owens Corning. I called the Indian HQ and, after a few days of persistent bugging, was put in touch with a local distributor. I was told they typically supply to commercial establishments, including theatres locally, and that I was the second fella in town that was crazy enough to call about their stuff for use in a HT. The absorption coefficient numbers seemed to be roughly similar to the OC 703 material that is available in the US market (and is used in the absorption panels of commercial acoustic solution vendors), so I made the decision to have the BAF in my panels (front wall and ceiling) replaced with this material.

The day the panels were reinstalled with the OC material, one of my daughters went (unprompted): Appa, the room feels much quieter now. I was struck by her perspicacity. I needed to actually play back movies and music to tell the difference that she'd instinctively grasped.

And the difference was significant: The missus, who left the room during the middle of the playback of the first race scene of Ready Player One before these changes because she felt it was too loud, now hung around for the entire duration of that 6-minute (?) scene. With playback levels now around 7 dB higher compared to earlier. Safe to say that the change worked. Things were looking up much more compared to earlier in the year.
 
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Diffusive blades installed on the front wall!

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After doing a bit of room treatment myself this thread was very interesting to read. I have seen this thread before but didn’t pay much attention to details. I noticed that you have placed the sub on top of a board with wheels. That’s is just to move the subs or fixed permanently?
 
To move. The Submersive is 130 lbs "light", IIRC (that's shipping weight, I now see. Actual is 120 lbs). I moved it from the front of the room and lifted it once on to my MLP and decided I wasn't going to take that chance again.
Your back will be ever grateful. If you try it again, your back may become grateful dead ;)
Cheers,
Raghu
 
To move. The Submersive is 130 lbs "light", IIRC (that's shipping weight, I now see. Actual is 120 lbs). I moved it from the front of the room and lifted it once on to my MLP and decided I wasn't going to take that chance again.
Well done. I developed severe back and neck pain moving the subs around. Now I just slide the subs. Since the floor has carpet the subs slide smoothly and effortlessly
 
Wow...that was a lovely enlightening read @liverpool_for_life

Thanks for sharing it :)
I guess Iam a convert now. But sadly won't have the space in a 11x15 ft room with a kids bed to probably get diffusion in, without making it look like a recording studio and not to mention a sound sermon from my better half too :D

But I really need to tackle my room, as it's acoustics are atrocious :D

And no point spending a penny more on the kit, knowing fully well that the villain is still there to kill the improvements :D
I agree. I actually moved from an apartment to a villa with a basement for HT for this very reason.
 
Purchase the Audiolab 6000A Integrated Amplifier at a special offer price.
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