Fixing my echo chamber

[meesbaker]

Alright after a good amount of research here and a bit of chatting and discussing I made a purchase. I was able to get certain components on a strong discount so I pulled the trigger. It is a pair of Martin Logan B1 Bookshelf speakers , an 8 inch Subwoofer and a wiim amp. Im overall very happy with it. The software works great and overall everything sounds very decent.

Main problem that I have is the room. At higher volumes everything becomes a bit mid heavy and boomt which is no surprise - if you talk in that room you can literally hear a mild reverb effect. The wiim room eq did a lot of good already but it cant do magic - the room is no good.

We got some furniture in there but overall it is rather empty - drywalls , 2 windows to the left side and hardwood floor with a more thin carpet/rug on it.


I bought a punch of acoustic panels from amazon which had good reviews , to work on it, they will arrive tomorrow. I will have 24 30x30 pads to place. Now my question is - wherd is the best point to start? Which is the most important?

The wall behind the TV and speakers? The wall behind my couch? The sides? The ceiling?

 

[masterhw]

How thick are the pads?

 

[meesbaker]

Am I allowed to link to amazon here? It is these guys:

https://www.amazon.com/dp/B0F8JJGVVN?ref_=pe_123509780_1038749300_t_fed_asin_title

 

[kemmler3D]

Per @masterhw 's point, if the pads are not very thick (depends on what they're made of, but 4" is probably a minimum) they're not going to help with boominess, they're going to make it worse.

Most thin acoustic treatments only work well for higher frequencies, like 1Khz. "Boomy" sound is below 300hz at the highest. To fix that, you need really thick absorbers, or what is known as membrane traps.

It's mostly bad news, these things are neither small nor cheap.

 

[meesbaker]

So these things will do no good basically? I was thinking anythings better than empty walls like it literally echoes when you talk in that room.

 

[masterhw]

ok 0.4 inches lol I don’t think they’re absorbing much.

I got some of the ATS 24”x2” hexagons to put on my wall and they help. I would consider 2” to be the minimum for meaningfully deadening. The rectangles are cheaper, and there are good DIY guides out there. the common theme is insulation as the core and just covering it with fabric you don’t mind the look of https://forum.hifiguides.com/t/diy-acoustic-panels/38143

 

[kemmler3D]

Am I allowed to link to amazon here? It is these guys:

https://www.amazon.com/dp/B0F8JJGVVN?ref_=pe_123509780_1038749300_t_fed_asin_title

These are way too thin to be effective at low frequencies. It is not only a matter of the density of the material. Low frequencies have long wavelengths. Stuff like this absorbs sound by adding friction to the air particles moving back and forth. The problem is that the particle velocity is close to zero next to the wall, so only wavelengths that are small have any appreciable motion that close to the wall.

If you want to hang some of these up, I highly recommend taking measurements (or at least doing listening tests) frequently as you add treatment. If the room already sounds "boomy" this will only be pulling out treble, so you don't want to go too far with that.

To the extent you have too much treble / high frequency (think 1Khz and up) these will help. It's likely you will find a benefit. "Echoey" often implies a wide range of frequencies.

The problem happens when you keep absorbing treble and the bass stays the same. Eventually the bass is overwhelming compared to the treble. So it's easy to overdo it with thin panels like this.

 

[meesbaker]

Hmmm I could probably still cancel the order

EDIT: Item is non returnable lol I guess I shouldve asked here first rather than blindly trusting amazon 5 star..,

 

[kemmler3D]

For a little casual treatment these are probably OK. Just keep in mind you're only pulling out treble and stop hanging them up as soon as you start to feel the tonal balance is going "dark".

If you want to get serious about it, and you have budget, I would get a UMIK-1 and take some measurements with REW. This will show you exactly where your problem frequencies are, and you can get the appropriate treatments for that.

Doing acoustic treatment by ear is like doing auto repair by ear. You may be able to get a rough idea of the problem just by listening, but you should pop the hood and connect the OBD computer before you start ordering parts...

 

[DVDdoug]

So these things will no good basically?

They should help a lot, depending on how much surface area you can cover. Just not with the bass. If you're hearing excessive reverb when you talk you "need" something.

A rug or carpet on the floor would help too. Sometimes you can hang decorative rugs on the walls. If you have a hard ceiling, acoustic ceiling tiles should help. Acoustic ceiling tiles can also work on the walls if you can make them look acceptable. But again, that's not for bass.

For the bass you might start with EQ which can be free if your source is a computer. It's better if you can measure the room first to determine the problem frequencies. "Diagnosis before treatment." You'll need a measurement mic (about $100 USD) and REW is FREE. And of course, you can measure and EQ the whole frequency range, not just the bass.

With bass, you get standing waves that depend on room dimensions. At different frequencies and at different places in the room you get the direct and reflected waves mix in and out of phase. Where they combine in-phase and sum you get a bump-up in frequency response and it can sound boomy and this tends to the most annoying result. The good news is that the bumps can be knocked-down with EQ.

Where the waves combine out-of-phase you get a dip in frequency response ("missing bass"). That's usually not as annoying but since the waves are canceled it can't be completely fixed with EQ... That would take "infinite" amplifier power and "infinitely large" woofers.

Bass traps absorb the bass that would otherwise be reflected and that smooths both the bumps and the dips. But, they are large and expensive and rarely used "at home". There are thick bass traps and thinner membrane traps.

Multiple subwoofers can also even-out the sound and it's a more common "home solution" than bass traps.

 

[meesbaker]

They should help a lot, depending on how much surface area you can cover. Just not with the bass. If you're hearing excessive reverb when you talk you "need" something.

A rug or carpet on the floor would help too. Sometimes you can hang decorative rugs on the walls.

For the bass you might start with EQ which can be free if your source is a computer. It's better if you can measure the room first to determine the problem frequencies. "Diagnosis before treatment." You'll need a measurement mic (about $100 USD) and REW is FREE. And of course, you can measure and EQ the whole frequency range, not just the bass.

With bass, you get standing waves that depend on room dimensions. At different frequencies and at different places in the room you get the direct and reflected waves mix in and out of phase. Where they combine in-phase and sum you get a bump-up in frequency response and it can sound boomy and this tends to the most annoying result. The good news is that the bumps can be knocked-down with EQ.

Where the waves combine out-of-phase you get a dip in frequency response ("missing bass"). That's usually not as annoying but since the waves are canceled it can't be completely fixed with EQ... That would take "infinite" amplifier power and "infinitely large" woofers.

Bass traps absorb the bass that would otherwise be reflected and that smooths both the bumps and the dips. But, they are large and expensive and rarely used "at home". There are thick bass traps and thinner membrane traps.

Multiple subwoofers can also even-out the sound and it's a more common "home solution" than bass traps.

Hey I dont wanna cut your reply short because you tackled many things and I am reading and processing all of them. Just real quick on that last point - how would multiple subs work with the wiim? Since both subd would hang on the sub out with a Y cable I guess the software be more confused what kind of subwoofer I have that blasts from 2 spots in the room

 

[meesbaker]

Also , I dont have a serious calibration mic atm but if it helps at all - these graphs is what wiins roomfit app spits out :

Not sure if that is any useful.

 

[kemmler3D]

Also , I dont have a serious calibration mic atm but if it helps at all - these graphs is what wiins roomfit app spits out :

View attachment 483159

Not sure if that is any useful.

Actually pretty useful, it does look like you have some extra treble going around the room. So I think the treatments you've bought will help somewhat. Like @DVDdoug said, they'll really work, but they work better the higher up you go. But that blue line is well above where it should be in the 8Khz+ range, so it might be pretty helpful with that.

 

[DVDdoug]

Since both subs would hang on the sub out with a Y cable I guess the software be more confused what kind of subwoofer I have that blasts from 2 spots in the room

A Y-Cable is fine. The difference/improvement depends on how the soundwaves mix in the room. The mic (and your ears) will pick-up the differences.
You might do some research about where to place the woofers, but you can also experiment and it will depending on how much flexibility you have... You don't want then "stupid places".

Oh... I forgot... You can also try moving one subwoofer. There's a "trick" where you put the sub in your listening position and then crawl-around to find the best spot to put the sub, but I don't know the details of what you're supposed to be listening for. But someone else will probably chime-in.

 

[tmtomh]

Also , I dont have a serious calibration mic atm but if it helps at all - these graphs is what wiins roomfit app spits out :

View attachment 483159

Not sure if that is any useful.

As @kemmler3D says, this is indeed useful - although turn your phone around for goodness' sake!

Seriously, though, these measurements appear to show three things:

1. As Kemmler notes, you've got seriously elevated treble from about 9kHz to about 15kHz. Since the Wiim EQ - and most other EQs too - does not correct up that high, you'll want to have some absorption to try to tame that. But with frequencies that high, you should be able to absorb/tame them with almost anything: those 0.4 inch panels you ordered, fabric window or wall coverings, a thicker rug, some pillows on the sofa - anything will help.

2. The raw response shows an elevated area around 100Hz. On the other hand, it appears the Wiim room EQ is already knocking down that 100Hz peak (and filling in that 200Hz dip). Hard to know if the "predicted" EQ'd response is accurate unless you actually measure the in-room response with the EQ applied. I would suspect there are still peaks in one or more frequencies between about 100Hz and 250Hz if you're still hearing that lower-mid boominess. I'd second others' recommendation for 4-inch thick panels. You could try 6 inch panels too, which will provide some absorption slightly below 100Hz, but I wouldn't go any thinner than 4-inch given the issue you have described.

3.However, before ordering thick panels, why not try moving the speakers and subwoofer around, as @DVDdoug suggests? These kinds of room modes - a resonant peak at a lower frequency - are always changeable by moving the speakers around. Now, whether your particular room allows you to physically move the speakers to a location where that room mode will disappear and you still get a nice stereo image, that's another story. And if you can't, then panels might be the way to go.

 

[Pareto Pragmatic]

But that blue line is well above where it should be in the 8Khz+ range, so it might be pretty helpful with that.

True. Odd that things would be spiked that much, but I don't use my Wiim for that, so no idea why it went that route.

Given bass issues, I would try lowering the bass boost bass to be more like 3-5db above the target line. So you might try lowering the sub gain a bit to bring that down. Or cut the EQ boosts in Wiim by 50% below 80hz..

A thick rug pad will help even under a thin rug. Better to have a thick rug on top.

Does your hardwood floor boom when you stomp it? If so, a rubber backed pad can help with that a bit. That's my experience with a very old hardwood floor.

What are your limits on decor? Does anything go, or does it need to "look like a normal room"? There are things that can help in both cases. For example, throw pillows... if you put them on the back of couches and chairs when listening, that can help a bit.

No limits? Likely thick panels air gapped off the walls, and a ceiling treatment or "cloud" hung from the ceiling would be the main suggestion I would offer.

But as I always suggest, try FREE things first. Moving things around and EQ adjustments are free.

 

[Keith_W]

The elevated treble could easily come from not pointing the phone in the right direction - e.g. reflections off his body, arm, table, etc. I would ignore that measurement.

 

[meesbaker]

Aesthetics wise neither of us is very picky main thing atm is cost factor

I did notice in the graph that we are really high still at 50 HZ. I set the subwoofer crossover from 80 down to 50 and I feel like that did a lot actually. The intro of MI8 Final Reckoning has a lot more attack now and more defined bass, sounds much closer to my sennheisers. When I go back and forth between 50 and 80, its like 80 introduced that muddy humming on the orchestra hits that clouds around the ears.

What exactly is the stomp test? So when I stomp on our floor its more like a loud clapping sound it doesnt really produce any bass or vibration.


Speaker placement is difficult I have the MLs just on the TV stand, I could change the sub placement though.

 

[Pareto Pragmatic]

What exactly is the stomp test? So when I stomp on our floor its more like a loud clapping sound it doesnt really produce any bass or vibration.

Basically play it like a kick drum, if it doesn't sound like a drum, no worries. Your floor is only reflective, not acting as a passive radiator.

If it did, you'd have some additional issues to consider.

 

[meesbaker]

Alright the panels are up. Doesnt echo in the room anymore, I can tell when I walk in from the kitchen into the living room and sing something how the reverb effect disappears so thats a start.

I ran some music and 5 mins of a movie and Subjectively it sounds a lot better but I learnt enough here to know how much that impression is worth without a new measurement. I cant do it now unfortunately because I have neighbors and its getting late and that testtone goes through flesh and bone

Ill hopefully get to do it tomorrow Ill keep yall posted and thx for all the advice I appreciate !