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

[liverpool_for_life]

Try 8 inch absorbers on front wall.
Of course space permitting..

Front wall first, yes. Unfortunately, space isn't permitting

Only 9 inches clearance from the front wall to where the screen drops down. And we need a panel to house the absorbent material. So, 6 inches is what's left for the absorber. It isn't too bad. It's what my speaker designer recommended as well.

 

[mpw]

Njoi..

 

[liverpool_for_life]

I had the same thinking that If the room resonates only till the transition freq, why apply EQ to the range above that..

That's a fair enough argument, if resonances were the only issue in the room. Reflections play havoc too, inducing harshness and a lack of a soundstage amongst others.

The truth is though that I've prioritized, for far too long, playback at reference levels. Reference is undeniably nice. The acoustic power and the wall of sound that one hears is great.

Unfortunately, until my room is complete, it is dawning on me that I'm quite possibly not hearing my speakers' natural tonality with EQ turned on to allow for reference level playback i.e. I'm having to EQ too high.

That ends today with the arrival of the minidsp 2*4 balanced unit. I'm EQ'ing only the subwoofer response and leaving everything else untouched. First impressions based on limited listening is positive.

 

[elangoas]

That's a fair enough argument, if resonances were the only issue in the room. Reflections play havoc too, inducing harshness and a lack of a soundstage amongst others.

Ok.. I will see how my situation is post absorption in the room..

The truth is though that I've prioritized, for far too long, playback at reference levels. Reference is undeniably nice. The acoustic power and the wall of sound that one hears is great.

Unfortunately, until my room is complete, it is dawning on me that I'm quite possibly not hearing my speakers' natural tonality with EQ turned on to allow for reference level playback i.e. I'm having to EQ too high.

That ends today with the arrival of the minidsp 2*4 balanced unit. I'm EQ'ing only the subwoofer response and leaving everything else untouched. First impressions based on limited listening is positive.

Ok.. That's great..

 

[mpw]

That's a fair enough argument, if resonances were the only issue in the room. Reflections play havoc too, inducing harshness and a lack of a soundstage amongst others.

The truth is though that I've prioritized, for far too long, playback at reference levels. Reference is undeniably nice. The acoustic power and the wall of sound that one hears is great.

Unfortunately, until my room is complete, it is dawning on me that I'm quite possibly not hearing my speakers' natural tonality with EQ turned on to allow for reference level playback i.e. I'm having to EQ too high.

That ends today with the arrival of the minidsp 2*4 balanced unit. I'm EQ'ing only the subwoofer response and leaving everything else untouched. First impressions based on limited listening is positive.

Do let us know reg the mini DSP and if put up some pics..

Am looking at it down the road as well

 

[liverpool_for_life]

Do let us know reg the mini DSP

With the minidsp 2*4 balanced in the chain, I no longer run Anthem's room correction.

Anthem AVM 60 pre-amp outs -> L, C, R and surrounds and to the minidsp for the subwoofer pre-out. Minidsp out to the Submersive Master.


Ran REW for subwoofer measurements at my LP and then used REW's EQ functionality to generate PEQ filters for the minidsp and loaded them into the 2*4 balanced. Results are below. +-3 dB from 42-80 Hz. I don't think I'm going to do much better, FR wise, with my current setup.

Hopefully, the additional pair of subs will help with the wide and deep null between 26-42 Hz. Bass traps to help with decay times. Until then, I'm going to sit back and enjoy the bass from my music and movies (what I can get with that null in place, anyways!).

Subwoofer response at my LP (9 ft from back wall):
---------------------------------------------------------

 

[liverpool_for_life]

Front wall treatment work in progress. Can (almost) see the finish line...

 

[liverpool_for_life]

Portion of front wall treatment done:




Initial subjective impressions:
--------------------------------

My subwoofer's amp died, so all impressions are with mains running full-range.

Stereo: I finally have a semblance of imaging, I think. Much better, with center reasonably distinct from left and right now. Way more details compared to before. Not in your face stuff, but things that are in the background. It is amazing just how much of the sound can simply be swallowed up by the room. It felt like I could hear every breath and every nuance in Kamal's Kanmani Anbodu from Guna. The place where he says 'Ahaan' (not to agree, mind you, but to say 'not really') is just wow.

Multi-channel: Slight uptick in vocal clarity. There are a few scenes that felt like I was in the middle of the action. For the first time ever. Watching the original Jumanji movie yesterday and there's a scene where Peter says something and the sound was so far out in the room it literally felt like he was speaking from right next to you. Incredible!

As the picture shows, there's a fair bit of the front wall still left to be treated. As usual, I can't wait.

 

[liverpool_for_life]

Most of the room treatment work so far has been to address just how reflective my room is. While the subjective listening impressions make it clear to me that there's a significantly audible difference between the same equipment in my originally untreated room vs currently, I figured it'd be interesting to compare measurements from then and now to see if they can objectively back up what my ears are subjectively, but quite clearly, hearing.

First, a very good article for background: http://www.acousticfrontiers.com/understanding-small-room-reverberation-time-measurements/

Onto the measurements in my room.

This is the center with no room treatment (January of 2018). If you look at 300 Hz (where the room likely transitions to being predominantly reflective as opposed to reverberant) and above, you can see decay times of 800 ms and higher. This was an incredibly "live" room. Very little possibility of playing anywhere close to reference levels without wanting to run out the room. Not to mention the attendant loss of details as acoustical energy hangs around for longer than is desirable in this range.



This one is a measurement of the center with the most up-to-date treatments (diffusers on the rear wall, absorbent panels on the ceiling and absorption on part of the front wall). As can be seen, a dramatic improvement from 300 Hz and up. Much closer to 600 ms now. Not as uniform between 300 Hz and 4 KHz, but the rest of the wall still needs to be treated. Playback at reference levels is now possible, with far more details and better clarity.



The difference in measurements clearly support the subjectively observed differences in listening. It really is like having a new set of speakers!

 

[liverpool_for_life]

Front wall absorptive treatments with panels covering roughly 14 ft by 7 ft:

 

[liverpool_for_life]

Haven't rerun ARC Genesis since the latest round of room treatment. I have changed my original requirement of being able to playback movies at reference without the need for subtitles. English movies provide a real impediment here due to the accents in use. So, it's now playback movies at reference without having to look at subtitles too much

Vocal clarity is a big difference now. It's only when I'm able to hear some of the lyrics clearly that I'm able to figure out in just how many cases before I was just humming along! Or simply making the lyrics up

Fairly significant increase in instrument separation. There is a difference in tonality that I personally like. Also, an increased weight with some instruments that is fairly palpable. And enjoyable!

All in all, this was a big effort. And it shows in the sound. Next up: Diffusive "blades" on the face of the panels. Can't wait!

 

[liverpool_for_life]

Diffusive blades. WIP. Can hardly wait to have them installed to hear what effect they're going to have on the sound.

 

[skumar]

First step: 4 poly cylindrical diffusers on the back wall (4 ft tall, 2 ft wide and 1 ft deep). Wood, CNC cut. Mostly hollow on the inside with some absorptive material lined up against the flat end.

These are effectively "diff-sorbers". The smaller ones will diffuse frequencies above 1KHz, while the larger ones will diffuse frequencies above 500 Hz.

What material is the cylinder made of? Plastic and then covered with vinyl or thin plywood bent into shape and covered with laminate?

Virtually all of the work on the ceiling was to minimize the effect of flutter echoes. 3 panels (they are anything but, to look at!) were built of wood (to prevent rattling) with a porous black polyester fabric on top. The backing of the panels is composite material, including aluminium. The absorbent is Bonded Acetate Fiber, which is a bit like cotton

The material at the back of the panel looks like high density foam, is it made with BAF?

 

[liverpool_for_life]

What material is the cylinder made of? Plastic and then covered with vinyl or thin plywood bent into shape and covered with laminate?

The latter.

The material at the back of the panel looks like high density foam, is it made with BAF?

As mentioned, it is composite material including aluminium. The absorbent on the inside the panel is BAF.

 

[liverpool_for_life]

Vocal clarity is a big difference now. It's only when I'm able to hear some of the lyrics clearly that I'm able to figure out in just how many cases before I was just humming along! Or simply making the lyrics up

Retro Friday today and the difference in vocal clarity is even more palpable. It's not a night and day difference, but reasonably subtle. The effect on my musical enjoyment is not subtle though. Very nice!

 

[skumar]

As mentioned, it is composite material including aluminium. The absorbent on the inside the panel is BAF.

Will it be possible to share more details on the materials used in each layer of the ceiling panels pls, with due consent from your accoustian friend? I gather the outer surface is polyster cloth, then BAF and then the top most is some kind of foam with aluminium composition. Is the layering correct and then what is the name of the top layer, any brand which offers that product?
I am venturing into room correction on a minor scale and would like to understand this more as ceiling is one place which I would like to try treating first.

 

[liverpool_for_life]

I am venturing into room correction on a minor scale and would like to understand this more as ceiling is one place which I would like to try treating first.

Please contact Orange Pale AED (https://www.facebook.com/pages/cate...Acoustics-Electronics-Design-455001354666480/) if you're interested in consulting with my acoustician.

 

[liverpool_for_life]

Diffusive blades being installed today. So, so excited!

 

[liverpool_for_life]

Diffusive blades installed on the front wall!

 

[raj12345]

Your thread is useless to read unless and until you tell materials from which your products are made of.