Soup's Adventures in Room Acoustics + Evolution Acoustics MM2

Yeah, after about a week with my A-3 this checks out. This sounds more capable at nuance/delicacy than how I remember the A-2. Not that it's a relaxed amp; it's still way livelier and more immediate-sounding than the Accuphase I just tried for a few months.

If I might be able to take a quick detour from Soup's thread to add some more context, one of the things that I didn't love about the A-2 was that, for my preferences, it didn't quite have enough sense of flow that lets me really connect with the music. That's why I sold it to try an Accuphase E-4000. The E-4000 is a bit rolled up top and has a 'liquid' japan-fi sound, which gave me the 'flow' I was looking for, but it was getting in the way of transparency/outright resolution. Going from the E-4000 to A-3 was like taking the window to the music out of the frame, like @sphinxvc put it when he heard the A-2 in my system after going through many other amps. The A-3 sounds more open, clear, vibrant, with sounds popping more out of the tapestry. It sounds easier to listen deeper into recordings because it sounds less smeared, overall, with better separation. Thankfully, it also has a better sense of flow than how I remember the A-2.

Hearing a rim shot, for example, on the Accu is one thing, but hearing it on the A-3 I can hear more 'around' the rim shot. The resonances of the snare drum, the air around the impact, the trailing decay of it. All more in focus and easier to follow. No parallel output devices (along with no negative feedback) seems to be the important for being able to render oodles of low level signals.

Bass definition, texture, tightness is much better on the A-3 vs E-4000. A big part of this is probably spiked feet vs the felt feet under the Accuphase. Kicks and bass lines much better delineated and clear. Also, I was recently reminded that all Soulnotes render quiet passages in an engaging way. It’s not lifeless or soft like some amps that need a certain level of volume to wake up.

I have to admit it took me about a day to get over the lack of pleasing liquid sheen the Accuphase brought to the table. Soulnote is a Japanese brand but doesn't have any Japan-Fi colorations. While it does have a smooth delivery, there's no real romantic sweetening or tonal tilting going on. It's also important to note that there's still probably too much liveliness for any Soulnote to be the tool for kicking your feet up to after a hard day and making sure you get a polite and relaxing aural massage from all genres of music. If a song has tension, drama, fury, etc. a Soulnote amp will give it to you.

 

Just checked out this amp. I like much about it but I hate the transformer placement, aiming the magnetic fields at the circuitry. I'm a fan of single pairs of output devices in a push pull arrangement. Efficient, no matching issues and often less bias required to connect the dots. Lots of goodness throughout.

 

Man, it has been quite a while since my last post on room treatment, but fear not! I have been a busy bee not just at audio shows(SWAF, AXPONA, Lone Star), but also testing/trying/improving the treatments in my room!

Last time, after playing with moving diffusion to the first reflection points on the side walls with the 3 panels I had, I really wanted to try more. This is when I discovered Danny over at GR Research had come out with some cheaper styrofoam diffusors, of the large 1D type and the smaller square 2d type. So I ordered 4 of the large 2ft x 4ft 1D diffusors for the side walls and 8 of the 2ft x 2ft square diffusors, I wanted to try putting diffusion under my ceiling treatment.

This also allowed me to have matching wooden diffusors from ATS across the front and then to have 2 diffusors on each sidewall at first and second reflection points.





As you can see, first I put them on top of the floor panels I have when I was taking them out of the box. this led to a very bright presentation. Later that day I got them all shove up into the ceiling clouds.

For quite a while I left them like this, they made the sound in the room a bit larger, but as we will see in a second, all was not well with these diffusors.

Some associates on discord were talking quite a bit about floor diffusors used at shows and their poor placement, but this made me want to try floor diffusion again more seriously. So I ordered 4 of the ATS 2ft x 2ft QRDs to put on my floor.



And what I have learned from this experiment is that floor diffusion, and even ceiling diffusion when it is this close just isn't feasible. You really need to be quite far from diffusors for them to operate effectively. While the sound does get larger, you end up with incredibly obvious comb fitlering/lobing from the diffusors being too close to you, most people online say you should be like 9ft+ from diffusors for them to work as intended, and I am ~10ft from my sidewall diffusors which work great.

so after all that I no longer have any diffusors under my ceiling treatment or on the floor.

 

Such a fun room to play around with! I had thought about floor bounce absorption and the feasibility of it. Isn't it likely since especially with floor standing speakers that it is usually compensated for or at least factored in of the design of the speakers/crossover?
I've seen some of those wooden racks in front of speakers at shows. Wonder if that does anything and is maybe less affected by distance unlike a diffuser.

Maybe i could get another dog so i have a reason for a 2nd tactically placed dog pillow!

 

Yeah I’ve had the floor absorption for quite a while, and I’ll have another update on that in a future post later today I hope.

 

Are there any sort of special footers or isolation pads under the speakers?

 

Right now there are some Herbie Gliders on them, they make it easy to slide em around. eventually when im confident they won't be moving anymore Ill put the spikes on.

 

So one of my plans ever since I discovered the Caruso Iso Bond I have been using at treatment panels was to replace the walls of insulation in the front left and right corners with that. the goal being that it would perform better, look better, and most importantly on the right side would be more stable and allow me to move it around a bit to make getting to the front door easier. And then I wanted to spread the bass wall out in the floor corners of the room on the sides and back to use as soffit bass traps.

So a few months ago I ordered 24 more panels of the iso bond so I could make one stack from floor to ceiling to replace the right side bass wall. it took its sweet time getting here and was spread out in time arriving too. So for about a week I only had half.

I wanted to play with this half stack of isobond to see about addressing differences in the right side of my room vs the left. There is a wall behind my seating position, the left side third is open to the kitchen completely, the middle third is a half height window into the kitchen, the right third is a wall. In my measurements I have this huge dip at 40hz on just the right speaker, that climbs back up to even at around 80hz. My guess was that this wall was causing it.

So I plopped the half high wall of insulation about two feet off the back wall directly in front of the speaker.



and the view from the seating position


it was directly to my right.

I just plopped this down, and I have to say, later on i did measurements, it made almost zero difference, but the difference it made audibly was pretty huge, it improved bass impact a lot. I also dont really have an explanation for why, specially after everything else I have done since, I still can't really explain the impact that 4ft high wall of Iso Bond had. A local even came over later on and confirmed what I was hearing with that wall. I pushed it down the hall and around the corner while he was listening and he yelled at me to bring it back immediately.


Ok, so about a week later, the rest of the Iso Bond finally arrived, that Saturday, I spent the day with my two half walls of insulation, pushing them all over the room listening and measuring. my goal was to try to see if I could solve my 40Hz issue on the right side.



I pushed those stacks of foam all over the room, putting them between the speaker, 4ft thick, and the side or rear wall, didn't make a dent in my 40hz issue. I also stacked it floor to ceiling against the wall into the kitchen in front of the speaker.



this also didn't do anything for my 40hz issue. Doing all of this I also learned that the Iso Bond doesn't really stay stable once you stack it over like 5ft high, I thought originally since its such a large rectangle it would be ok...I was wrong...



The friend I mentioned earlier, was here, and so we finally tore down the bass wall and spread it out as soffit traps and put the Iso Bond in its place.

But we were sad cause we didn't have the short 4ft tall wall next to us anymore, so we tore down half the wall and put it back, but then I had to figure out what to do...

 

So where we last left our intrepid hero his room looked like this



half a bass wall on the right, soffit traps of insulation and a half height bass wall to my right.

I couldn't wait for more iso bond to show up, it can take like a month....well, when your name is Soup, you've got a hammer and everything looks like a nail.



Of course I brought more insulation, it was delivered the next day. This time I wanted to try something though. That friend hypothesized that maybe the double wide wall was what was stopping the left side from having the same 40hz issue, so I figured id give that a shot and do double wide on the right too!

Unfortunately this wasn't really any better than the single wide wall, so wasn't worth making the front door completely inaccessible. I ended up putting the 2nd stack back in the rear left corner in the kitchen.



But now you're asking yourselves, what did you do with all that insulation then?

The first thing I did was expand my ceiling treatment. Since I put them 4 treatments id put up up, id wanted to spread them out to the sides more, so I did that, and then I added another set in the middle since I already had the rope and the unused hooks in the ceiling, I threw that up. I also added 2 more sets further into the room, they ended up sorta over the speakers.



I also decided to put a stack in front of the wall to the kitchen, but I cut all the panels in half, so its about a foot thick.




All of this combined, the new stack of insulation in the back left, the soffit insulation, the 3 new treatments on the ceiling and the stack against the kitchen wall, lead to noticeably cleaner bass in the room versus previously, though the measurements dont show a whole lot, the spectrogram got a bit cleaner down low.

 

What's your flooring like? Is there a basement underneath? since we're halfway into the realm of crazy, you should get yourself an accelerometer and see which surfaces of the room vibrate.

 

Nah, im in texas, im on a slab, ive got a fake wood floor on top of that.

 

Just an idea, have you tried playing a 40hz tone and walking around the room and see if there is a buildup somewhere? I mean the wavelength for 40hz is huge but maybe a tuned absorber can work there or hell maybe demo one of those PSI active basstraps that go down to 15hz?

 

Yeah, playing problem frequencies in REW and then hunting for them in the room is a common occurrence for me haha been doing so since back on page one!

I actually tried an avaa trap. the friend that came over when I was messing with my tower of foam, brought one of his. We tried it in quite a few locations and it didn't help. I actually went and talked to the PSI folks at AXPONA for like half an hour, showing them my room, treatment, measurements, etc. They said it's not a mode, it's a first reflection and their traps won't help.

I do still have a few more spots I want to try one, so at some point I will borrow my friends again to see what's up.

 

You're not messing around lol! Hmm yeah if they say it's a 1st reflection where the f**k is it then. Can a tuned absorber work there?

 

Ive always heard you can't ever have too much diffusion. Of course, thats within the limitations of your room, dont be too close to your diffusion as was discussed a few posts back. But I wanted to try more! So I ordered 5 more 2ft x 4ft QRDs from ATS, this would allow me to have 4 across the front wall and 3 each on the side walls, replacing all the styrofoam diffusion I tried from GR research.



the room looked like this. I had also seen other put diffusion behind the speakers so I wanted to try that as well, I stacked the GR diffusors on top of each other behind the speakers.

both of these are cautionary tales though.

The front wall, because of the bass wall on the left side, won't fit all 4 diffusors across but centered, they are slightly offset, by like 6-10 inches or so. This lead to some weirdness/lobing in the listening position, causing some harshness.

I have also had a harshness to the sound ever since I put the bass walls in, it wasn't terrible, to some it might have just been. slight brightness to the sound, which is what I thought as well. but it turned out the bass walls were causing the issue. The diffusors helped me realize this. It got worse with them there, so I took them back out, and it partially went away but not completely. So I swapped in some absorption panels behind the speakers. my thought process here is that my mids are transmission line loaded with huge openings in the back, and with the bass walls being so close and reflective at higher frequencies it was causing issue, putting the absorption there wiped out an issue id had in this space since the beginning.


I also told @Riotvan that I would be talking more about floor treatment. I still had some spare iso bond panels sitting around, so I randomly decided to put them on top of my existing floor treatment....

this was easily one of the most impactful changes I have made in this space to date. Ill say that again, making my air gapped floor treatment 8" thick instead of 4" thick is one of the most impactful changes I have made since I started this journey, and I dont know why I didn't try it sooner, but here we are, we are learning as we go!



The first panels I put down, as I talked about back when I did it, made a minor change, but one I couldn't go back to not having, it cleaned up some of the imaging and treble, wasn't a huge game changer, but was meaningful. doubling the thickness of the trap, transformed the bass in the room. I have been hunting more impact in my bass since I started this, and this was what I needed to do to get it.

I believe this comes down to floor bounce and will be highly speaker dependent. my speakers however, play down very low from the mid range drivers, they both play down to about 100hz, playing 100hz from so high up off the ground, means that floor bounce will be well within their pass band, and the frequency was such that one panel wasn't enough to take care of it, but with the added panel I am able to solve, or at least greatly ameliorate that floor bounce, massively improving the impact of the bass.


So this is the current state of the room



This includes the cleanup brought about by the recent acquisition of the audio wise opto-dx that I wrote about briefly here. and some cinderblock cable risers, gotta match you know...

My current plans are still to replace the bass walls with caruso iso bond, but other than that, the room is feeling more and more done.

 

Occasional tables. On one occasion, table; on another occasion a Cuisinart box!

 

You mean the decay plot/RT60 got cleaner?

 

Yep. more bass treatment in the room meant cleaner bass decay times.

 

Any plans to integrate subs into the setup? It could simply be that certain nulls can't be treated and you have to cut those frequencies from the main speakers and have them come from somewhere else in the room.

 

I'm not really looking to fix much else at this point, the drop at 40hz on the right speaker isn't super audible in most music. I may eventually try adding a sub, but most of that problem is above where id want to cross it over. I would mostly be doing it to take that bottom octave or two's load off the speaker's woofers and would be able to use an even larger woofer to reproduce them.