How to "mount" acoustic foam ?


My main system is in my partially unfinished basement.
While I have finished the ceiling and have nice floors / rugs - I do like the industrial / rough look of the concrete walls....I just finished painting them but don't want to install any sheetrock / finishing material.
Instead I want to buy acoustic foam (2inch depth squares) and mount them to the walls - front / back and sides
And here are my questions:
1. Should I just use glue and apply the foam squares directly to the wall ?
 - IF YES - what glue should I use? I know there is the special construction glue for laying floors etc..... I now they sell it also for concrete and stone application - sold in caulk like tubes 
2. Should I first apply the foam  to a plywood / wood and anchor that to the floors ?
 - IF YES - I would imagine a few concerns: 
-  Will that wooden structure bring about sound resonance that I am actually trying to control ? (Wood isn't as bad as concrete but still....) 
-  Will I have to add a layer of caulk or similar filler between the wall and  the wooden panel? Obviously the concrete walls are not super smooth so the wood panels will not be in perfect and uniform contact. They will be held rigid with the specialty screws drilled into the walls....but still 
- What type of panels should I use....I was thinking anything from very thin cardboard like materials (to minimize any resonance from wood) to 1/2 inch plywood for rigidity.
IN SUMMARY: 

 I am leaning for the 1/8inch thick boards - In my mind it would provide smooth surface to mount the foam onto, retain the acoustic profile of the foam, and then just hold it all in place up on the wall with 4 bolts (each corner)

Anyhow....Any other tips and advice about proper installation would be appreciated.

Thank you!! 
ether
I usually mount mine side saddle.
But seriously, acoustic foam is one of the biggest scams ever perpetrated on naive and gullible audiophiles. Yes, I know what you’re thinking. “But what about all those recording studios that are filled with the stuff?” 😛 What’s even worst you assume a little bit sounds better so you go overboard. Before you know it the walls are covered with it. “But it can’t hurt the sound, the recording studios use it.” 😩 Acoustic foam is the poster child for expectation bias.
ok...you still haven't contributed to my post....YOU just made a bunch of assumptions, including telling me I am assuming things
1. I am NOT covering my entire walls with anything...I am actually trying to do proper room treatment which includes Tube Traps, acoustic panels and foam
2. Believe me....an unfinished basement with concrete walls will benefit from careful and smart placement of various dampening materials... foam may not be the best but it certainly has its place in the overall design. 

So....again...if somebody has some good tips on mounting acoustic foam to concrete walls - I would appreciate it.

Thanks!
A good place to start is a clap test to see if you have an echo. You can tame the echo by using what you suggested above with the foam & 1/8" boards. Try to locate them near the 1st dispersion bounce points which would be the surfaces closest to where theoretically the tweeter & mid-range meet a surface (wall, ceiling, floor). That would be 180 degrees for a dome tweeter. If you have bass issues, maybe a pair of bass traps in the corners behind the speakers. Also, I use triangle corner tunes in the upper corners of the room. I would also get your ProAc's out into the room so that the speakers are 1/3 out from the rear wall, 1/3 from your listening chair and the chair 1/3 from the rear wall.
Using Auralex 2" Studiofoam and LENRDs in my listening room.  Back wall, from the ceiling to one foot below my ear level.    The room overloaded quickly, without the stuff, at my typical listening levels.   I found latex construction adhesive, to work well(been hanging there for the past 20+ years).  
@ether the point @geoffkait is making is that any amount of acoustic foam is audible and deleterious.

I have a fully treated room with tube traps and diffusion along with a range of SR treatments. I was using small (6”x12”) bits of foam to break up reflections from the edges of my components. As soon as I took these out I realized they create a harsh and edgy timbre.  

Please don’t use any foam in your room. Treatments from GIK are quite cheap (I ended up with a pair of custom GOBOs to address my component stack issues) and will sound so much better. Even natural rugs or wall hangings will be better than synthetic foam
But seriously, acoustic foam is one of the biggest scams ever perpetrated on naive and gullible audiophiles.

FALSE!

We’ve already gone over this in at least one other thread. Consider that GIK Acoustics acknowledges that 4 inches of acoustic foam panels equates to 1 inch of their fiberglass (and other materials) product.

Any other tips and advice about proper installation would be appreciated.

OP, I use foam acoustic panels, albeit not on concrete http://halr.x10.mx/AV.jpg

In my case they are mounted three different ways. Bass traps in the corners were adhered with a 3M spray glue. Wall panels were adhered with a 3M velcro strip. The ceiling panels were installed with (less than desirable and very few) carpet tacks.

Try the velcro strips in your case.
Perhaps you haven’t heard Melamine acoustic foam, SONEX or foam that looks like SONEX. I acknowledge there might be some kind of foam that doesn’t hurt the sound, I just never heard one is all. Fiberglass is not foam, obviously. Hey, I’m not trying to disparage all acoustic panels. For slap echo Michael Green’s Echo Tunes work great. But SONEX Melamine foam or similar foams - like the foam in Ikea chairs, for example - do actually suck, making the sound phasey and wooly sounding. I can even hear the effect of SONEX when I take it to another room. Ikea chairs - another sonic catastrophe that seems like such a good idea. “SONEX, trusted by professional studios everywhere.” 😛

One final thought: acoustic panels and Echo Tunes and Tube Traps and really all acoustic devices, even tiny little bowls, are trickier than they appear to correctly set up or apply. What is needed is the out of phase track on the XLO CD. The same track used for finding the absolute best speaker locations, which of course change as you apply more and more room acoustic treatment. It’s a fluid situation. Everything is in flux. Been there done that. 😬
@ether 
What did you really expect from geoffkait?

I'm using 12x12x2 inch foam, which I assume is what you're working with. I'm sure there's some adhesive that grabs that stuff well, but I wouldn't bet on anything in particular. I had to resort to mechanical means; T-head pins. It's a simple, reliable solution. 

I have a friend who owns a recording studio and he makes his own solutions out of rock wool. They're basically 1" x 4" frames 2' x 4' filled with a layer of rock wool and covered with thin speaker grill-like cloth. Some are free standing on legs. Some hang from the ceiling. Some get tossed around according to where he needs to kill sound. I tried a couple in my room and they sucked huge amounts of sound out of the room. I'd make 2" thick version if I were to build them and balance them with diffusers. This might not be a bad solution for you given concrete walls. 
Post removed 
@ether
What did you really expect from geoffkait?
+1

Just check out his website, he actually tries to sell this snake oil to the gullible, he has no shame, tells you something about him.

http://www.machinadynamica.com/machina5.htm

http://www.machinadynamica.com/machina33.htm

Cheers George
Oh, my! I’m being ganged up on by the Gang that Couldn’t Shoot Straight. 😩
@gdhal   Hal, you may want to pay attention to what @folkfreak  and @geoffkait  are saying regarding this.
@david_ten

I’ve payed attention. For one, I disagree with the presumption that "treatments from GIK are quite cheap". I have personally been in communication with GIK. Price/value ratio is always a personal matter and opinion, with respect to what is cheap, or not.

I do agree, however, that "even natural rugs or wall hangings will be better than synthetic foam". In my case, this is somewhat moot. I realize there are materials "better" than foam. No matter what is obtained, there is always something "better", especially in this hobby of audio and the quest for utopia/nirvana.

I’m satisfied that the foam I’ve installed has done the job I intended, which was merely to "take the edge off" so to speak. No doubt though there is more to be had should I choose to go that route. I appreciate the/your tip.

EDIT:

So here’s my analogy.... I’ve used foam not with the intention of scoring a home run, but merely to get on base. And to that end, I’ve certainly achieved it. This despite with Geoff would lead one to believe which is that it does nothing at all..... or further, that it has a negative effect. WRONG. I have plenty of third-party independent lab results, my own ears, and testimonials from other users of acoustic foam to reiterate that acoustic foam is a solution, albeit not necessarily the best solution.
I’m sorry I was not able to communicate clearly enough. I’m not denying that acoustic foam will perform sonically and damp midrange tones. The issue is that in doing this it also imparts an audible sonic signature that is harsh and ultimately undesirable. I’ve had the same experience with synthetic rugs on the floor in comparison to wool, they work as advertised but you can hear the effect, it’s a sort of tinnitus like effect (ie a harsh but low level high frequency ringing)
@folkfreak

Apology accepted but completely unnecessary from my perspective.

In no way shape or form am I experiencing a sonic signature that is harsh and ultimately undesirable. In fact, this is partially what I’ve cured by installing the foam.

If I do the "clap test" in my listening space, there is absolutely no echo or reverb what-so-ever. Isn’t that the goal, or at least one of the most important goals in room treatment?

And, getting back to cost for the moment, when I was in looking into a GIK solution, I was in the low thousands of dollars. When I looked at foam, I was in the low hundreds.
@gdhal you will not hear any problems with foam and a clap test. However try playing female vocal, listen with and without the foam and listen to tonality rather than frequency response (ie try to tune out the Echo you are using the foam to address ). Better still try putting some natural materials (eg a rug or thick sweater) at the reflection points and compare the sound 

I am also surprised by your GIK quote, as their 2’x4’ spot panels are $60 each you must be covering a very large area - over treating a room is also a danger ...
@folkfreak 

I actually tried an army blanket (wool) at one point to cover my television, as my speakers are between them. This is an older photo. I've since installed some more acoustic foam and have moved the speakers further forward of the tv. http://halr.x10.mx/AV.jpg

As to female vocals, I'm of the opinion I am reproducing them accurately from a tonality perspective.

As to GIK cost, the numbers included "professional" installation. Installing heavier (with respect to foam) panels requires far more attention to doing it "exactly perfect" so it doesn't rain down from the ceiling, tear at the walls, etc.

Further, it is my understanding that the point of this thread - as stated by the OP - is to understand *how to mount (install)* acoustic foam. We have since diverged into the merits or lack thereof with respect to acoustic foam, and for that the OP deserves an apology.

I'm not interested in debating the merits or lack thereof of acoustic foam in this thread. I'm rather satisfied with the sound of my system, and take solace in knowing that it could only get "better" should I choose to devote more money, other resources, etc. at it. In my case, improvements can be obtained by "upgrading" anything from the electronics, to the speakers, to the cables, to the room treatments, etc. 

Moreover, the overwhelming majority of music that I listen to (and collect) is Grateful Dead http://halr.x10.mx/shows.html For those familiar with their music, I'm confident they would agree that (a) much of their live recordings are excellent quality sound boards and (b) more so than any other band, they often sound fantastic irrespective of the who, what, where, when, why and how of the playback mechanism. 
gdhal
“Moreover, the overwhelming majority of music that I listen to (and collect) is Grateful Dead http://halr.x10.mx/shows.html For those familiar with their music, I’m confident they would agree that (a) much of their live recordings are excellent quality sound boards and (b) more so than any other band, they often sound fantastic irrespective of the who, what, where, when, why and how of the playback mechanism.”

Anyone else feel just a little uncomfortable about that paragraph? Not the Grateful Dead part -well, maybe a little 🤡 -but that the playback system/room doesn’t really matter? Whoa! This appears to be a perfect example of what I like to call Stove Piping, which is what happens when audiophiles work in a vacuum of sorts, on concentrate on a relatively narrow range of music or whatever and develop systems and concepts in a (limited) “stovepipe” fashion, without the benefit of shared knowledge and experiences. No wonder many audiophiles have such widely diverse opinions and conclusions about just about everything.
Laughing....
@jafant 

Unclear to me me what you find humorous, nevertheless, in the case of my posts, the information I've provided herein is true.
Per @slaw and @geoffkait , I removed the 4 x 24x48x2" acoustic foams I installed a few weeks ago. When first installed, there appeared to be an improvement in control of the music with better depth. However, after some further listening tests, I have to agree. While the sound is a little "wilder", it is freer. The music breathes, is louder, more dynamic. The foam basically killed the music. I have found the same effect with some mats. Damping can be deleterious. 


noromance
Per @slaw and @geoffkait , I removed the 4 x 24x48x2" acoustic foams I installed a few weeks ago. When first installed, there appeared to be an improvement in control of the music with better depth. However, after some further listening tests, I have to agree. While the sound is a little "wilder", it is freer. The music breathes, is louder, more dynamic. The foam basically killed the music. I have found the same effect with some mats. Damping can be deleterious.

>>>>>Thanks for posting your results. What I think happens is that the foam changes the nature of the acoustic wave traveling through it. Obviously the acoustic wave actually travels though the foam twice, once through the foam to the wall then back out again to the air. So any effect the foam has on the acoustic wave is doubled. As I intimated earlier ANY foam in the room has a similar deleterious effect on the sound, for example the IKEA Poang Chair that has foam seats and backing. Just when you thought it was safe to go back into the water. 🦈 Effective, non-interfering acoustic solutions such as Michael Green Echo Tunes and panels, Tube Traps, Skyline diffusers and others do not (rpt not) contain foam.

What I think happens is that the foam changes the nature of the acoustic wave traveling through it. Obviously the acoustic wave actually travels though the foam twice, once through the foam to the wall then back out again to the air. So any effect the foam has on the acoustic wave is doubled. As I intimated earlier ANY foam in the room has a similar deleterious effect on the sound, for example the IKEA Poang Chair that has foam seats and backing.

At least Geoff is "thinking" :)

The one thing Geoff doesn’t mention, *even IF his post is true* is whether or not the "deleterious effect" is worse without (correctly placed and designed) acoustic foam!

EDIT:

Besides the fact that there are numerous manufacturers of acoustic foam, and customers who report improvement in sound when using foam, this article is rather succinct and informative as to its potential benefit(s). 

https://en.wikipedia.org/wiki/Acoustic_foam
I used the term deleterious. I am not denying that the foam tamed certain aspects of the sound. It did. And extremely effectively. Bass was reduced by a significant factor while higher frequencies were "tamed". Whether foam sounds bad in itself, I do not know. All I do know is that it took the life out of the music. I tried reducing the amount of foam gradually and each reduction improved the dynamics, bass and loudness. This has been an interesting excercise. I do believe the space needs some treatment as it can be a little "live."
However despite it being in a corner of the basement, there is a lot of free space for the sound to dissipate into so reflections etc. are not as bad as might be imagined from the photos. There is some "confusion" in the upper mids when played loudly and mid bass is a little plummy on some recordings. I will look into the options mentioned. Thanks.
What we have here is simply the difference between experience and idle speculation. Of course foam seems like a good idea. That’s kind of my while point. Plus you’ve got the fact that many recording studios have been using SONEX or similar foam panels like forever. So, it’s no wonder that audiophiles get behind foam so strongly and why expectation bias is so powerful in this case. Most likely gdhal is experiencing the Backfire Effect here, more convinced than ever he must be right. 😛
Most likely gdhal is experiencing the Backfire Effect here, more convinced than ever he must be right.

I ain't often right, but I've never been wrong.

gdhal, my absolute favorite comment of yours is, “I wasn’t aware fuses could be upgraded.”
That’s priceless.
@geoffkait

You do realize that I’m very much aware that you’re "following me" throughout the forum from thread-to-thread and post-to-post. Splendid! You could learn something.

As to what you regard as priceless: "Money, who needs it, let me live a life free and easy".
I’ve been stalked by funnier. Say, this isn’t mapman, is it?
GK,

The secret is out. You love me and you know it! I saw you were pining in public for weeks during my recent absence. Must be my sense of humor. Sorry, I’m taken. Plus I don’t swing that way.
One reason for not using foam is that some of it decomposes over time, turning into a crumbling, sticky mess. I've used in in rehearsal spaces in the past, but no more. Owens Corning 703 or equivalent in wooden frames is relatively cheap; that's what all the products from GIK and the others contain. The professionally made sound panels are reasonably priced, but the shipping will kill ya.
One reason for not using foam is that some of it decomposes over time, turning into a crumbling, sticky mess.
True, if time is measured in eons, figuratively speaking. Everything decomposes over time.
 
mapman
GK,

The secret is out. You love me and you know it! I saw you were pining in public for weeks during my recent absence. Must be my sense of humor. Sorry, I’m taken. Plus I don’t swing that way.

>>>>>mapman the comedian. 🤡
Hey now! gdhal
not laughing at you, friend. I, too, enjoy the GD especially the live offerings.
Very fine music to demo any system.
Happy Listening!
Back to original question. I suggest not affixing items to your concrete wall. Messy and make placement experimentation (tuning) challenging. Instead mount whatever you wish to try on old fashioned economical fibreboard pegboard. Drill small holes in the concrete for the tiny nails that will suffice to hold your item. There are translucent twines-think fishing line- that will not be obvious. Now you can experiment like a pro- and get the results that satisfy you. Mix,match,move,enjoy. 
I strongly suggest Velcro strips if you are mounting light weight foam. Since moving the pieces around to get best result will probably occur, you can’t beat them for semi permanence. Use glue and your  stuck. (Ouch)
I strongly suggest Velcro strips if you are mounting light weight foam. Since moving the pieces around to get best result will probably occur, you can’t beat them for semi permanence.
Agreed, wherever possible. Velcro may not be strong enough for ceiling mounted foam unless one uses an inordinate amount strips. Even then, mounting in the manner that the instructions dictate can be challenging. I found that I needed to apply both the velcro to the foam first. 
I'm using Primacoustic panels purchased from Sweetwater Sound. They can be applied to hard surfaces using adequate lengths of 2" Velcro attached to the hard surface, then the metal mounting brackets to the Velcro. I needed to do that for some of the surfaces in my dedicated listening room. Highly recommend this product. 

Tom