Soup's Adventures in Room Acoustics + Evolution Acoustics MM2

This is going to be a pretty stream of consciousness type thread. also, yes I know all of these pics will have huge r/malelivingspace energy, you're gonna have to get over it.

At the end of June I bought a house, new homeowner! My main motivation for doing so was A, that I wanted a dedicated space for my stereo and to not share walls with neighbors, and B, to not have my rent keep going up even though rents in Austin are falling. 4 years in my apartment through all of covid was enough.

When I was house shopping I was specifically looking for a house with a large living room for the stereo. Turns out finding a 3 bedroom 2 bath house with a large living space and not much other "wasted" space is pretty hard. It's not perfect, the ceilings are only 8ft, but the large living room is directly next to the large kitchen, making for a rather large audio area.


I moved in in mid July, the day I moved in @Erroneous came over and helped me unpack the speakers(he also helped me pack them up the night before, what a homie!). This is what they looked like, first thing sorta setup in the house



Over the next week or so I spent some time moving them around to find the best position for imaging and staging. They ended up about 6ft out into the room and about 11.5ft apart.

The thing I didn't mention about this room is that it is incredibly echoey. It fails the clap test in a laughable way. An aside, I somehow won the acoustics lottery in my apartment, it sounded kind of great, specially considering the concrete floor, bare walls, and very little furniture. I had no obnoxious bass nodes, good bass performance overall. That said, the sound in my new house was pretty much terrible. There was almost no staging/imaging to be heard, everything was super smeared, lacking detail, etc. I knew the room needed treatment but I was busy with getting settled into the house, going back to Korea, etc. Life was getting in the way.

Fast forward a few months to mid September and I am sitting at work, once again with the ATS Acoustics page open looking at panels, but this time I was like, I need to stop procrastinating and overthinking this, its time to just order some panels and start experimenting! So I did! I grabbed 6 of their 4ft x 2ft x 4" absorption panels. They showed up a week and a half later.



This was an absolute game changer in the sound of the room the focus, imaging, stage, details, all snapped in. I places absorption at first reflection points and on the front wall as well. At this point I was over the moon, this was starting to sound maybe even better than the apartment! Except maybe in the bass, we will come back to that. The clap test was greatly improved, the absorption panels were doing their job in the room.

at this point I am a complete convert in the realm of room treatments after hearing the difference they had just made, so I immediately ordered 3 of ATS's 4ft x 2ft QRD diffusion panels and 2 corner bass traps to put in the one corner that exists in my room back in the kitchen. a week later they show up.



This honestly made a much smaller difference but a still meaningful one. I think the biggest difference was in the bass and how it presented. Punch and definition both improved. The highs were less rolled off, which was a small side effect of having the absorption at first reflection points at first. The room was sounding excellent.


The elephant in the room is the bass though. I had very little of it. At this point I was assuming my poor Acoustic Zen Crescendo Mk2s just couldn't play deep in this large space, I was very wrong which we will find out later. When I was positioning the speakers, I wasn't concerned much with the bass, I kept pulling them out into the room till the sound stopped sounding like it was compressing against the front wall, the bass was suffering, but this was a tradeoff I was willing to make as everything else was improving so much.


Next time we will take a slight diversion into speakers.... You can find my impressions from AXPONA in April here

 

As I said before, one of my main motivating factors for buying a house was the stereo. That said, I knew after I moved I was going to have more space and was already thinking about speaker upgrades. I went to AXPONA to do some research, there's so many brands and rigs there in one spot. Unfortunately, overall, it didn't help me make any decisions. Sure @Priidik 's Forza's are stunning speakers, but I'm not really in the market for 170k speakers. The only other speaker I heard that might be a meaningful improvement on my Acoustic Zen Crescendo Mk2's was the Rockport Atria.


So for the months since AXPONA I have continued to do research and keep my eye on the used market. There is actually a used pair of Forzas at The Music Room that were at ~115k back in April and are now down at 84k, they drop in price 1% every Saturday. but I decided I didn't want to save up for years to buy something like this, its beyond my personal point of diminishing returns for audio. So I was keeping an eye on used Rockports as well, the Cygnus seemed like the sweet spot in the lineup, used ones pop up often enough, I think the used price will be dropping below 40k, still a massive amount of money.

This is where a dark horse speaker enters the chat. The Evolution Acoustics MM2. I had previously owned a pair of MMMicroOnes from them. When I bought those back in 2013 I went to a very kind gentleman's house in Cleveland to listen to them. He also had their then top of the line model the MM3, which is the same as the MM2, but with an additional woofer on top for a WMTMW configuration, running with dartzeel amp and pre, wave kinetics turn table, playback design dac, and like 3 reel to reel decks with a whole wall of tape, it was in in a room build within a room. I was a total scrub at the time so I take these remembered impressions with a grain of salt, but that room is still one of the best rigs I have ever heard. This has always been in the back of my mind. And further research now with my current experience and sensibilities also lead me to believe these would be excellent speakers, particularly when you consider the current used pricing on them.

So I was also keeping an eye out for a used pair of MM2 or MM3. As it would happen, a used pair in a unique black finish popped up several months ago and I started keeping my eye on them. The price dropped quite a bit and several weeks ago I reached out to the dealer and made a deal.


They are large speakers. 18" x 30" x 53" and weigh 400 lbs each. ribbon tweeter, 2 accuton ceramic mids and a powered 15" sealed woofer. They showed up a week and a half later, last Thursday in their 4 large crates.



I had arranged for the Austin crew to come over and help me set them up Friday, but another newcomer to the group volunteers to come over that night, and the two of us, after many trials and tribulations, got them out of their crates, assembled and into place.



without the grill




These speakers are kind of incredible, but I'll go into more details on that in a further post. My Crescendos got relegated to TV duty in the other room. I have officially joined the Big Woofer Club

 

Wow, those are impressive looking speakers!

I'm no scientist/engineer, but I went down a few rabbit holes a decade ago when building out my basement home theater and listening room. With that disclaimer out of the way, I'm surprised you don't have some absorption on the ceiling or floor for that matter. My basement "cave" is about 71/2 feet tall as its beneath a sunken great room and I found a shag area rug and a couple "cloud" treatments above the primary listening position made big difference. But even so, I think my stereo set up sounded much better in our 10' tall bedroom for the few weeks we waited for the construction work to be done.

As an aside, that is a gorgeous room and there is something to be said for listening to your favorite music in a comfortable chair, with lots of natural light, a fire going and a nice drink. My HTR is great for movies, but I rarely if ever go down there to just listen to music, your set up looks super "inviting". Anyhow, congratulations on the impressive set up and enjoy! Looking forward to reading more in the future.

 

thank you, I think they look pretty nice as well. They are large and heavy, but also pretty thin all things considered.

There is yet more to come in this story of room treatments! I haven't yet gotten to ceiling treatment even now, but it is absolutely an area of interest for me. the main reason I haven't yet is that I knew I was getting new speakers, and I am new to all this treatment stuff, thats why the wall treatments aren't mounted, but rather at height on cinder blocks, this allows me to experiment and move them around, or easily swap diffusion for absorption. Theres no analogy for ceiling mounting as just leaning them against the wall, so that said, I also want to wait till I have the location of the speakers really nailed before I treat the ceiling.

It is a good idea though! The ceiling and floor are the two closest "walls" to my head when listening, so treating them would be very valuable

 

Where next our intrepid heroes left off, I had finished setting up the MM2s, it was 1130pm, and it turned out they only accept cables with spades, not bananas...all my cables were bananas, so after a quick journey to another friends house to get some spare cables with spades at midnight, I came home and plugged my new speakers in...

Only to be pretty disappointed in the results. See my previous comments about me thinking the Crescendos couldnt pressurize this space. One of the things I was looking for from my new speakers rated down to ~10hz with powered 15" woofers was excellent bass, but what I was hearing was only deep sub-bass. Nothing I was listening to had any punch. I was wondering if this was just a case of them being sealed? I don't think I've ever owned speakers that were sealed woofers before, but I didn't really think this was a brain burn in issue.

So the next morning I contacted the local friend who let me borrow the cables and has experience doing measurements to see if instead of coming to help assemble speakers if he would be interested in coming to help me do some measurements and figure out what was going on in my room and with my new speakers.


later last Friday, we started doing measurements, and while we did a ton, the first like baseline measurements were all we really needed to see.



I had some serious bass suckouts happening in the mid-ish bass. depending on channel, ~56hz, 90hz, 160hz, etc. lots of broad suckouts happening. The thing my new MM2s were doing that my Crescendos hadn't done was play with authority below those suckouts, just look at that 5hz extension! this was doing a great job highlighting the issues in the mid bass, but making me think less of the speakers. We even brought the crescendos back out and the bass graphs lined up very well in the parts of the spectrum they could play.


At this point I know I have a problem and am just trying to brain storm how I can solve it. Saturday morning I am on discord with friends doing just that. As I said in my previous post, I really wanted to treat the ceiling, another friend was saying similar suckouts for them went away after finally treating the ceiling. I was also joking about maybe vaulting my ceiling, I had even talked to my realtor about it when I was first looking at the house, but I didn't really want to do this as it would be expensive and I don't think the trusses and such would be conducive so getting it to look nice would be even more expensive. But I had a bit of an epiphany when one of my friends said after vaulting it I could stuff it with rockwool, I was like, we don't need to vault it if were going to stuff it with rockwool anyways, I could make the ceiling acoustically transparent and put a giant bass trap in the attic, that sounded like a good idea.

Another thing people were pointing to is the fireplace in the front left corner being a potential problem spot, removing the fireplace wouldn't cost a fortune. There is also the wall behind the listing position. I said before the space is next to the kitchen, about a third of that is just open, another third is counter height with the top open, and the last third is a wall. I could open the kitchen up the rest of the way across.

With all of these ideas floating around in my head to fix my bass issues, later Saturday afternoon I played quite a few of the null frequencies with REW and walked around the room looking for the hotspots on the walls/corners. All of them had a hot spot on the inside left at the ceiling of the fireplace, so clearly the fireplace was causing a problem.

Saturday evening I was reading online about room treatments in general. Some blog posts from a gentlemen named Ethan Winer, he seems to be some sort of authority on the topic. He mentioned offhand that if you wanted to treat bass, you could throw bags of insulation, without opening them as the plastic wouldn't harm their ability to absorb bass, into a corner. Now, this isn't a strategy many people would be willing to use, but I am anything but most people. So Sunday night I ordered 18 rectangular batts of insulation from Home Depot to be delivered Tuesday.

 

Tuesday morning rolls around, and they get left on my driveway while im in the shower. I walk outside thinking I might be able to carry them inside before I head to work, only to see this.



Well....that is less than ideal. I wasn't expecting all of the bags to be open on one end, and when I want to just leave them in my living room, this won't work. So that night I go to Home Depot on the way home....all of the insulation is basically open like this in one way or another, so I guess this is what I am stuck with. So I buy a roll of stretch plastic like you would use for a pallet and come back home to begin my work.

I will tape them all closed and then wrap them long ways twice to seal all the insulation in, this took longer than expected, but later that night I had this magnificent beast in my room.



my bass wall was complete! My goal with this was to create a bass trap in the corner that would remove the fireplace as a problem, without having to actually remove the fireplace first. So this is an 8ft wide, 8ft tall, 17" thick bass trap. I sat down to listen and my mind was blown, I had bass!!! It was slightly bloating in some ranges, I think this bass wall was causing a new mode to manifest at my listening position, but overall this was a massive improvement to the sound, I was over the moon with the success of this relatively inexpensive hack. All the punch was there that I had been missing previously.

The following night I used to the other 6 batts of insulation to build a smaller matching wall on the other side.



This removed the bloat I was hearing the previous evening. I think there might be some new smaller suckouts.

just today my own measuring mic has arrived, so I will be able to get some measurements of the effectiveness of my new bass traps soon, but the listening is incredible in here now.

 

One benefit of the bass walls I hadn't considered in advance is how much quieter the room is with them there, I don't have a measurement from before they went up, wasn't thinking about it, but if the AC and fridge are off now, I am getting a noise floor of around 22.5-23db according the NIOSH app on my phone, which to me is pretty impressive.


Another interesting thing is that when we brought the Crescendos back out to measure them a week ago, I also listened to them for a few songs just to do a back to back comparison with the new MM2s. I was actually amazed at how much worse it made the Crescendos sound. When I first listened to the MM2s, I knew they were good, but man do they make the Crescendos sound not great in comparison. A lot of the space is gone, the dynamics are gone, things just sound a lot flatter overall. These are a bigger upgrade than when I went from the Acoustic Zen Adagio to the Crescendo Mk2, and the cost outlay in percentage terms was much smaller. Its weird to say for a speaker that was so expensive, but these MM2s are actually pretty decent value to me

 

It's funny when your bass traps are so large they are almost behaving like walls and changing your room nodes.

Also, your speakers kinda look like dongs and I can't unsee it now...

 

Big Dong club?

 

First round of measuring myself is complete, obviously different mic, not exactly the same location, etc.



It does look smoother, but the dip at ~162hz is still pretty bad, and now I've got some peaks at 250 and 400 that are more pronounced than before.

Im also very curious about the little shelf from 1300-2000hz....thats coming from the accuton mids not the tweeters from what I can tell. it was also there before

Like I said before, I think overall it does sound better than without the bass traps, but there is still more work to be done clearly.

 

I would be concerned about health risks from uncontained fiberglass. Just my intuition – recommend researching the topic.

 

When I was in full-on anti-audiophool mode, I used to love his stuff. I don't know if he coined the word but he was certainly one of the people that popularised the word itself and spread the word.

Some of his videos on bass traps and stuff are very NSFW. You could try adding a naked woman or two to your setup .

 

For anyone thinking to buy insulation for bass traps, there's usually an acoustic rated version available too for maybe 10% more. Up here the most common one is called Safe'n'Sound, down there I think it's called Sound Guard.

If you're ever doing a home reno and tearing open walls, I highly recommend stuffing insulation into the walls and in between floors. It really makes a huge difference in the "coziness" of your home. In my previous home when we went through a basement foundation repair, everything was opened up and I figured might as well spend the extra bucks to insulate everything. I couldn't believe just how much of a difference it made. It wasn't like a recording studio, but simply being down there felt calmer with a lower ambient noise and less reflections from your own body and voice (granted I also had wall panels instead of drywall which is quite reflective).

Another random note on bass traps or absorbers in general, they are more effective when they have air behind them. Such as the case when corner traps have the corner (duh) behind them. We all know that sound reflects at a wall, but there's a silly boundary layer thing wherein the energy does transfer to the wall but the wave actually turns before touching it. Think like when you're driving towards a dead end and you gotta turn your car around. You don't actually scrape the edge of your car against the wall you turn before you reach it. With sound waves, you want them to pass fully through the absorbing layer before they start to turn around, thus making two complete passes through it

Who could forget the demonstration of standing waves using a bra...

 

In my reading online I found that once you get to a certain thickness, the effectiveness of standard fiberglass actually surpasses that of rockwool, and for bass you really need thickness as Marv so eloquently put above. At my 17" thick I don't think the difference is important, and if/when I build a frame to build an actual trap I would do 2ft thick.


agreed on the air gap, that is because the standard absorption traps work on velocity, not pressure. pressure is highest at the wall where you measure the highest SPL, but velocity would be highest 1/4 wavelength out. My ridiculous trap is about a foot out from the fireplace which is itself a bit out from the corner. and like you said, passing through the trap twice also helps

 

It was suggested to me that I use a moving mic, averaged, method for frequency response measurements, I used this guide on ASR.



Left is red, right is greed, and this is with the "psychoacoustic" smoothing option in REW.


I also tried putting one of my absorption panels on the floor at first reflection points on each side, but that made very little difference




If I can figure out the 160hz issue and the 1k issue, I think I will be pretty happy

 

It's disconcerting that those two sentences are one right after the other

 

Don't forget to take into account SBIR for mid bass dips and the same goes for the distance of your listening position from the rear wall. You might have some overlaps with similar distances from side to side, front to back etc etc. Measure everything and see if some are in the same ballpark distance wise and try and change those. Front wall(and some sidewall) symmetry is king, chaos in the back is not such a big deal ime.

 

Yeah when I was doing placement for the speakers I was very cognizant to make sure I wasnt getting close to having the speakers be the same distance from rear and side walls, and im about 11" further from the back wall than the side wall.

But speaking of SBIR, I was messing around with a calculator today and I do think a lot of the issues im left with are from floor and ceiling issues, I need to treat the ceiling at the very least, even if I don't go crazy with a full ceiling bass trap like I was musing about earlier in the thread.