Sound correction in small room

Hello All,

I’m having a hell of a time with the sound in my newly constructed sound room and have spent the past couple of months learning about acoustical engineering (4+ months in theory being proactive, the past 2 weeks reactive trying to solve specific problems). I know there are a multitude of threads, videos, and websites about the subject across the innerwebs and I have looked at many, but they start to blur together so I am hoping to get some tips on my specific situation. But first, a couple of disclaimers: 1) 5 months ago I knew nothing about acoustical engineering... I now know just enough to know that I don’t know… 2) I blew waayyyy (I mean wayyyyyyyyy) past my intended budget many many moons ago.. So please keep these two things in mind when commenting/making recommendations. I’m trying to provide the necessary information without being too verbose so apologies for the length of the post…

The main characters:

Raven Nighthawk integrated tube amp (I believe 2x20w…)

Tekton Double Impacts (yes, I put 5ft. tall speakers in a room with a 6 ft. ceiling.. no, I can’t change that fact..)

Denon dvd player for the source (it’s been around a while and was probably lower midrange 8+/- years ago…)

Supporting cast (My room…):

Dimensions are 15’1” x 10’2’x 6’3” (176.5x122x76.75) yes, the ceiling is just over 6 ft. tall as I did the decoupled thing and there was also venting in the way

carpeted floor, standard walls and ceiling (textured and painted drywall), components are on 5’x2’ table, and there is a 58 inch plasma mounted on the wall. Single seat glider/rocking chair and footrest, 5’x5’ cube bookcase, minifridge, and lamp. I’m skipping over the sound proofing measures used when building the room as I don’t think they are relevant at the moment..

The villains:

1) I have a bass tone (produced by the bass guitar) that just floods the room if I have the speakers at the 2 ft. by 1ft. and toed inward placement. Ironically, moving the speakers back to only 2-4 inches from the front wall helps with this, however, I lose the lower/bottom end almost completely. From what I have read this is completely backasswards and makes no sense but here I am…

2) I am failing the “clap” test which leads to lack of clarity/intelligibility (I believe acoustical panels should address this… see below)

3) Not getting that “wow” factor that I know these speakers can produce (I had them hooked up to my main system for a few days whilst building the room and it was definitely there.. I can best describe it as lacking the immersive power that I was expecting… maybe described as loud and clear with all sounds well represented without blasting at the same time???)..

1st attempts at sound management/correction

1) Speaker placement (2ft. from front wall/1 ft. from side walls, 3in.from front wall/~1ft. from side walls, as well as a multitude of other positions)

2) Seating placement (38% from rear wall.. can’t do it from the front wall, too close..) as well as further back and forward.. Farther back seems to sound better at the moment

3) Equilateral triangle placement of seat and the speakers (ironically very close to 38% anyway…) making sure the sound shoots behind me, not directly at my ears

4) Diffusion: 5’x5’ cube bookcase with CDs and whatnot on rear wall (also a minifridge and lamp…) A few of the resources either directly stated, or at least implied diffusion can be effective this way…

Forthcoming sound management

1) I am attaining the materials to build 6 panels (2’x4’ with OC 703 already purchased) and will put 4 of them at the 1st and possibly 2nd reflection points with the other 2 as clouds at 1st reflection. The only door to the room may impact that 1st reflection point on one wall though…

2) Considering bass traps but want to see how the panels affect things first.. Regarding this, I love that deep low bass but I want it accurate and appropriate, not that singular hum sound

3) Also considering more panels (the only real space left would be the front and rear walls. Possibly more on the ceiling)

The actual questions

1) Does it seem like I am on the right track?

2) What am I missing/what should I be attending to that I am not?

3) If I end up doing bass traps, what material???

4) Any other suggestions (speaker placement, seating location, more panels, etc…)

Thank you in advance, these forums are a great resource!

I would get the Master Handbook of Acoustics and pay special attention to the chapters on recording studios (which are often small).

how do you feel about tearing out the ceiling???

panels at the reflection points are for higher freq.s not bass - think in terms of two problems: 1. bass relates to how big waves stack up (superpose) based on room size; 2. high freq.s are affected by surface textures and are dealt with by ray tracing

the TV is a problem - I have one there too & just live with it - you can build a cover or a retracting roller curtain if you want

buy a hand mirror and recruit an asst. to hold it for you

bass traps can be had with other tmts. integrated - I think GEK makes them & they will give you free advice - it is not the material so much as the size and shape (anthropologists have discovered that the ancient peoples (the Greeks, IIRC) embedded wine ’bottles’ in the walls of their amphitheaters to act as Helmholtz resonators)

a distributed woofer system may help a lot

do you have REW? it can save you years of messing around...

Easy solution: Call GIK Acoustics. Best prices and effectiveness.

In particular, you need bass traps.

You have a relatively small room. My room is somewhat similar shaped at 11 x 17 x 9. Based on amroc, you have room nodes at 55hz, 75h, 90hz, 110hz, 111hz, all at different walls, but always in the corners:

If you had the budget, I would get the GIK Monster Bass traps with FlexRange Limiter (important) to fill the rear corners. You can get two 2’x4’ panels and two 2’x2’ panels to fill the entire rear corners. This will definitely help with bass and bass definition. If you wanted to, you could also put these in the front corners (if you had room). The GIK "FlexRange Limiter" panel works significantly better in the bass region (60hz to 120hz) and will also not absorb as much high frequencies. Absorbing too much high frequency can suck the life out of the room and you only want to absorb the mid/high frequencies where it is important to do so. I have a couple in my room and I can attest to their effectiveness.

You should also research Speaker Boundary Interference Response (SBIR). Your Tekton midrange is very close to the ceiling and your speakers could be very close to the side walls. Putting the Owens 703 on the ceiling and walls surround the speakers may work out better than trying to target the first reflection points. That’s what happened in my room because I had to put my bookshelves about a foot away from the side wall due to space restrictions. In any event, the 703 will help with slap echo wherever you put them.

If you wanted to try to build your own bass panels, I would use two different types of panels. I would put a layer of Owens 2" 703 FRK in front and then a standard 2" 703 panel in back (making a 4" panel). The FRK has a metal foil coating. This servers two purposes. The foil acts as a "membrane" to resonate the bass frequencies, and the resonation energy is absorbed by the 2" fiberglass behind it. Also, the foil will reflect more mids/highs instead of absorbing, which can be a good thing. The FRK will absorb the lower frequencies better than non-FRK. The GIK Monster Bass traps with FlexRange Limitor will still work better in my opinion. The GIK stuff is so cost effective that you wouldn’t really be saving much (maybe 25-30%) if you attempted to build the same thing yourself. Additionally, the FRK foil will reflect reflect high frequencies even more than a standard wall. Having too much FRK foil in a room can cause the high frequencies to become out of control. So it is always a fine line of experimenting until you get the best results. The GIK FlexRange does not have this high-frequency reflection problem.

Check out the ATS Acoustics website. You can buy different type of fiberglass panels direct.

Time and patience and a little DIY will prevail. Only then will you come up with the changes necessary in your unique room.
It’s not clear from your post which wall you have the speakers on but I think it’s the short wall. Have you tried them on the long wall? My room is a similar size to yours and this works very well for me 

You can use the Cardas speaker placement guides as a good starting point, treating the corners with traps will then help on top

Hello la10slgr,

It appears that your components are resting on a table.

Resonance formed from vibration without an exit, trapped inside the chassis is affecting your components and loudspeakers operational efficiency hence clogging all your signal pathways (mechanical, electromechanical and acoustic).

Chances are your table and table top are also adding audible unwanted frequency and noise into the environment from vibration.

Until you get the equipment under control - mechanical grounding or isolated in some manner, searching for an acoustic cure will only serve as a temporary Band-Aid or confuse the issues even more. 

In my opinion, your immediate issues are mechanical and not acoustic.

Our recommendation would be to mechanically ground your loudspeakers and electronics package and hear more of what your equipment is capable of in performance, then listen to see if any additional acoustic products are required.


Star Sound

Hey everyone!  have seen your responses but havent had a chance to digest all of the information y'all have so graciously provided (daughters bday party this weekend) so will get back asap.. thank you so much for the recommendations and it definitely looks like there is a lot of information here...  

as a starting point, i am definitely looking for thoughts about my speaker placement and then progress to the other ideas.. i had considered long wall placement (they are on the short wall) but decided against that in the building phase for whatever reason was logical at the moment so now i am 99% locked into the current locale (outlet placement, connections, holes in the walls, etc..)

once again, truly, thank you!  I know no one in the audio world where i live and do not feel comfortable plugging the stores for their knowledge and then not hiring them so this kind of help is extremely helpful and appreciated!
I had a hell of a time getting my room to sound right. Here's some things that finally got it right:

To tighten the bass, get two unfinished Mapleshade maple platforms  and spike them to the floor. Then spike your speakers to the platforms.

To improve the room:

Get at least a ten-pack of SR's HFT's and place them around the room as directed

Get two pair of the Shakti Hallographs.  One pair goes behind the speakers in the corners of the front wall. The second pair goes behind the listening position. Adjust for the best sound.

Happy listening ...


Some add-ons I figured out this weekend or forgot to mention:

1) The problems occur at louder volume/listening levels, about 90-95db

2) Problems also occur with louder music (louder as in typical rock music vs. mellow or acoustic music)

These two points may be obvious to some…

3: I do have speaker isolation planned with bamboo boards (some would call them cutting boards from Ikea..) to put on the carpet and then the floor spikes..  Haven’t added them on yet as I am still scooting the speakers all over the place testing different positions…


Ok, so here’s where things stand:

1) Let’s get this out of the way 1st…  I tried to not so discreetly allude to the fact that this room is already wayyy over budget…  So far over budget that had I known what the room itself was going to actually cost I would have had to at minimum drastically alter my component purchases (which in hindsight could have been done differently but what’s done is done…) or forego the project altogether…  If there is a comma in the price (e.g., $1,000+…) it is not gonna happen.  As it stands, anything that costs a couple of hundred bucks brings out a heavy sigh…  Not complaining, just stating the facts as they are….

2) GIk agreed that my speakers close to the front wall is an appropriate placement.  I was so focused on making sure I was giving accurate information I forgot to dive in to the logistics of why this works but regardless, he agreed when I said it sounded the best so far…

3) Need to get those panels constructed and hung

3a) still investigating best placement for the panels.  It seems the 1st and 2nd reflection points are the main idea here but honestly, they both may be covered by a single panel.  Ironically, my wife doesn’t have a small mirror in the house so have to go find one.  Should this be correct, this opens up the option of placing some panels either behind the speakers on the front wall or on the back wall (keeping in mind I am talking about panels, not bass traps)

4) Seems to be a pretty common consensus that bass traps need to happen so I will get on this. 

4a) spoke with GIK and got recommendations (very helpful by the way, just as many have mentioned) basically it comes down to me being on the right track with the panels and adding bass traps in all 4 corners of the room.  The total is approximately $700 but I can’t tell exactly as the website and my computer are not playing nice with each other as I can’t add the traps to my cart…

4b) I need to investigate the DIY route for building bass traps and am still looking for recommendations for material so I can compare prices with GIK.  It seems the OC 703 could be a component but either need to use it in combination with something different (alternating 703 and 703 FRK) or use something different altogether.  If I am reading correctly, it seems something with FRK needs to be involved so the bass trap doesn’t suck the life out of all the mid and high frequencies… Thoughts?

4c) triangular pattern that stacks up on top of each other (pancake style) vs. panels that are simply placed in the corner.  It seems the triangle option has more mass and therefore should absorb lower frequencies and do a better job overall when compared to panels placed in the corner.  Am I interpreting correctly?  Cost/benefit?

4d) as I stated earlier, I don’t want to be that guy that plugs a business for information and then goes somewhere else..  I need to do the aforementioned price comparison and if it is comparable, or at least somewhat in the ballpark of reasonable, I will use GIK but if there is a big difference then I gotta consider the alternatives..

5) components on the table – I can see how the table might be a reflector o’ sound and I do have a small rack style stand (3 shelves, maybe 2.5’x2.5’x2.5’) that I can easily swap in.  Thoughts?

6) Did some research on what was mentioned.  My interpretation:  Room nodes/modes = 2 “beams” of the same frequency meet and either create a peak (in phase) which amplifies the frequency or null (out of phase) which negates the frequency and cancels it out.. there’s a lot of math after this…  At this level, it makes sense. Am I correct in my interpretation?

7) @auxinput, thanks for the graph/chart.  I honestly can’t say that it all makes sense to me but from what I can decipher (as demonstrated in point #5 directly above) it seems the bass traps and panels will be a big part of the solution, if not the solution.. is this an accurate interpretation?


Again, my deepest gratitude for the input..  It seems like I am making some headway, at least in theory at this point..  By all means, I am still open to input so feel free to chime in (but please make sure you read point #1, the second one, above)

You are correct in your understanding of what "room nodes" are.  I do not understand the math behind room nodes either, but the amroc page was really intended to show you what the "node frequencies" are and where they are the loudest (most pressure).  The locations where they are the loudest are the best places to put bass absorption panels (which are generally located in the front/rear corners).

If you were buying GIK, I recommended the Monster Bass Traps with the FlexRange Limiter because it excels in absorbing the 80-120 frequency range and it also does not absorb as much mids/highs.  You could get the triangle shaped bass traps if you wanted (these are the GIK TriTraps).  They will have only a little bit better absorption in the very low frequencies (such as 40-60hz), but it is not much better than the Monster Bass Traps.  However, the Monster Bass Traps with the FlexRange Limitor have a significantly better absorption in the 80-120hz area.  See measurement reports here:

To give you a point of reference, I have 14 sound panels in my room.  Only 4 are full absorption types:

6 - Owens 703 FRK 2"

4 - Roxul Rockboard 80 2" (full absorption)

2 - Monster Bass Traps 7" with Flexrange Limiter

2 - Limp Mass panel bass panel tuned to 63 hz

Four of the 703 FRK are partially covered with towels - this was me tuning how much high-frequency reflections I actually had in the room.  The FRK panels actually worked very well in doing bass absorption down to 70-80 hz and would be an excellent alternative to the GIK Monster Bass Traps.

I did not double-up my FRK panels to make 4" panels.  I used black Guilford of Main fabric to cover them, which is more expensive at about $14 per yard from ATS Acoutics.  It requires 1.5 yards to cover one 2'x4' panel.  I just wrap the cloth around back and use spray glue to glue it on the back side of the panel (no side frame).  You could use duct tape if you wanted to.  The cloth is purely aesthetic and has no impact to the acoustics.  You can get very cheap burlap cloth (it would look crappy), but it would work fine.

Look in the ATS Acoustics clearance section for some deals.  They are currently selling grey burlap for $0.50/yard.

If you are under a tight budget, a 6-pack of 2" 703 FRK panels is $109 plus shipping from ATS Acoustics.  They are an excellent source and I have used them several times.  This will allow you to completely fill your front/rear corners (you can cut a panel in half to make a 2x2).  Just sit them in the corners at an angle.  They are VERY light and stiff enough that you don't need a frame.  You can use your existing 703 for 1st reflection or SBIR points.

I think the Monster Bass Traps with FlexRange limiter will probably be better, but they are significantly more expensive at $127 per panel.

Thinking about this further, the very low bass is always hard and expensive to treat.  The general broadband panels (even if they are very thick) are only average at absorbing the bass.  However, if you know the target frequency, you can get an effective panel.

We know that you have a room nodes at 55hz, 75h, 90hz, 110hz, and 111hz.  The FRK or Monster Bass Traps will effectively handle anything 75hz and above.  If you wanted to treat the 55hz problem, I would call GIK and have them make you a custom Scopus Tuned Membrane Bass Trap that is custom tuned to 55hz.  They have off-the-shelf models at T40, T70 and T100.  You would just be having them build a custom "T55" model (they will do this).  I suspect the price would be somewhere between $230 and $250 for a 2' x 2' panel.  It would probably be about 7-8" thick.  I would get a couple of them (at a minimum) and put them on the side wall floors near to the back corners (since amroc tells us that the 55Hz node is loudest on the side walls).

This is somewhat similar to my limp mass panel that is tuned to 63Hz.  I also plan to make another two limp mass panels that are tuned to 50Hz.  In my room, the 50hz also occurs on the side walls.  I will say that all my treatments have significantly increased the volume and definition of bass.  I am sitting at about the 10 foot spot in a room 17 feet long.

Alright, i did the cardas placement which had the speakers 33.67 (to center) from side walls and 54.53 (to front of speaker) from what i call the front wall...  it was doable but admittedly pretty much out in front of the tv and in the middle of the room, 1/3 anyhow... in my current state it didnt improve sound much, if at all, so gonna have to wait til some panels get built (and bass traps but still working on those logistics) and test again...
Auxinput, totally missed your last two posts... will review and may have some questions

At 11:57 of this youtube review:

“A lot of people are going to look at this speaker and ignore the fact that the midrange is being handled by two 6” woofers and a tweeter array… and what that means is unless you have a big powerful amplifier, you’re not going to get the kind of dynamics out of this speaker that is just going to punch you in the chest.  Some people are going to be disappointed with that, some people won’t care, but you at least need to be aware of that”

 This is also going to be more constrained if you got the 4ohm version of the Double Impact, where your 20 watt tube amp may have a little more problems handling it (i.e. it’s not going to be the same as with a high current Class A/AB amp with a big power supply).

 He also talks about how a good amount of the midrange is actually reproduced by the outer ring of tweeters (6 tweeters).

Been a while but figured I may as well finish this up...  Here's what I ended up doing:

1) 4 bass traps - 6' tall and essentially floor to ceiling (of course the air vents are right where these would go so had to leave some clearance) placed in each corner of the room.  They are 4 inches thick and are made of 2" thick OC703 and 2" OC703 FRK

2) 6 panels -  Each is 2'x4' and I placed 4 on the walls (1st reflection point, and to the side of listening position) and 2 on the ceiling slightly forward and/or above the listening position.  These are 2" thick and made of OC 703

Results:  Sound is now under control (huzzah!!!) as that bass tone that was overpowering the room is leveled out and I can pass the "clap test" with no echo when the listening chair is placed under the cloud panels.  However, if I move the seat closer to the rear wall I can still get an echo.. 

I continue to play with seating position and speaker placement and am constantly amazed at how an inch here and there can alter the sound so much.  If I move forward I get the soundstage but lose the bass and vice-versa when I move the seat back towards the wall.. I tried the Cardas placement for a rectangular room and for my situation it was just ridiculous as the speakers were essentially in front of the tv and it didn't sound so great either...  Also tried the equilateral triangle method and that met similar results...  So I turned to my own ear and trial/error... Lots of trial and error....

Overall, I give the effectiveness of the room treatment, and the sound presentation, a 9/10 and in some aspects a 10/10 but I can't seem to get that perfect sweet spot where I keep the bass and the soundstage and maintain it from one style of music to the next (said differently: I can attain 10/10 but then I put in a different type of music and that particular set up is no longer ideal so find myself scoochinig things around again...)  I'll keep tinkering with it but am happy that the problems are 90% taken care of and that last 10% is something that I don't mind playing with...

Thanks for all the help!!!  I  LITERALLY could not have done it without all the helpful suggestions and guidance.