So I bought Bass Traps, but still having issues...

Hello, I have an 11' 10" x 12' 5" room with textured 'popcorn' ceilings, carpted floor (almost shag), and textured drywall for walls. I am in an electronic duo and I am responsible for mixing and mastering our songs, so naturally I want to make it sound as good as possible with what I have. I have 2 5" monitors by the way. I mostly mix at medium to low levels, but I have noticed in my current set up I have some serious bass issues. Very very little bass at the mix position, no bass in the middle of the room, but lots of bass at the opposite corner....atleast alot more bass compared to the little bass at the mix position. I understand the concept of standing waves, but I am unsure how to resolve it. So I went out and bought 8 2' Auralex bass traps and placed 2 in the middle of each corner thinking this would atleast help, but I still have the same problem. I tried moving the monitors and the mix position where the orange X's are, but still the same issue. I understand that the corner is not the best place for placement, but I would have thought the bass traps would have helped even a little. They did help diffuse othe overall sound in the room however. In the corner placement, the room is still symmetrical even if it isn't ideal. Currently the mix position (in the corner) is in the green area of the excell sheet 3.5 ft away from the two walls. I am going to try placing them in the middle of the back wall and see if that helps, but I have my doubts to be honest. I still think I will have the same bass problem. I am just really looking for some suggestions to fix this and maybe on layout or even an explanation as to why the bass traps are not working like I expected them to. Thanks in advance. * Oh, I wanted to also mention that I close both closet and hall doors when mixing and that in the bottom right corner the bass is not as inense as in the bottom left.

I could be completely wrong here but I will go out on a limb and say that if your "bass traps" don't go from floor to ceiling...they don't trap diddly. Or at least enough diddly that you can hear it. And certainly not enough diddly for your dough... :( Also, I would suspect, using the small monitors that you are, the more you trap bass...the more you will realize that you aren't going to get much big bottom out of those 5's. You should however be able to recognize the bass a little better in the mix. Consider first treating the corners from floor to ceiling. There are plenty of tutorials on building your own traps for cheap on this board. From what I have experienced, they work better than the "foam" solutions. Is the room exactly square as you have drawn it or is it rectangular by the way?

Aloha, Could it be that you are sitting in a "null zone?" (equals = no bass) Try measuring your position and then comparing your measurements to the graph you posted and you may find yourself (and that center spot of the room) in a null. You also want to avoid sitting in a "peak" as well. A couple of thoughts: - Is it at all possible to position yourself centrally along the "back wall" with your speakers firing straight back towards the closet door, or along the wall with the window firing back at the entertainment center? - After repositioning yourself, try stacking your bass traps 4 high in whichever the front corners are. Hope this helps, Aloha 8)

Hey guys thanks for the replies. WiseMindsRecordingStudios: I actually bought the 5's with the idea of later adding a sub, but it will be a little while still before that comes into the equation. The room is actually not a perfect square I just freehand drew it just to give everyone an idea with what I'm working with. One side is about a half a foot longer than the other. I bought the foam at a really good price, so I would feel bad returning them. If anything I would go back and get more and fill the corners like you were saying. kendale: It is possible that I may be in a 191hz dip or null...or atleast on the border of it. I am 3.5 ft away from each wall. I think I am going to switch things around a bit today and take some of your suggestions and see how things sound. Hopefully, centering the mix position and monitors on either wall will help. :D

Ok, so I moved the mix position and monitors to the middle of the back wall and stacked 4 high of the 2' bass traps to fill the front corners. I measured my mix position to be 3.5 ft from the wall which according to the graph is in an ideal position. It seems to have helped a little, but not nearly where it should be. I am comparing it to the nice bass I am still hearing on the opposing corners behind me. Maybe I shouldn't be? (the monitors are 5" krks by the way) I supposed the bass in the corners behind me could be boosted, but to me it sounds more accurate to the tracks that I play to test it. Any other suggestions or insite to remedy this? (aside from getting a sub) Thanks!

Oh, one more thing. Are the room dimensions 11' 10" x 12' 5" going to be more trouble than its worth to fix since it is almost a square? Just add more absorption? ie. more bass traps in the back and broadband absorbers on the walls? Thanks.

Aloha,

Ok, so I moved the mix position and monitors to the middle of the back wall and stacked 4 high of the 2' bass traps to fill the front corners.

That's great! :wink:

I measured my mix position to be 3.5 ft from the wall which according to the graph is in an ideal position.

Okay, cross check: With your mix position 3.5' from the wall, are your monitors & mix position forming an isosceles triangle? (equal distance between monitors, equal distance from mix position to left speaker, equal distance to right speaker)

I am comparing it to the nice bass I am still hearing on the opposing corners behind me. Maybe I shouldn't be? (the monitors are 5" krks by the way) I supposed the bass in the corners behind me could be boosted, but to me it sounds more accurate to the tracks that I play to test it. Any other suggestions or insite to remedy this? (aside from getting a sub)

The corners are basically funneling all of the bass energy into a "pool" so to speak, which is not a good point of reference. If your monitors are the RP-5's (or similar model), they are spec'd at 53 Hz-20k. Here's a review excerpts from a mixguides article to consider: http://mixguides.com/studiomonitors/Rev ... itors-604/

The RP-5 frequency response is given as 53 to 20k Hz, ±2 dB. The crossover is at 3 kHz using a custom 24dB/octave crossover filter. The RP-5 uses a 15W amp for the tweeter and a 30W amp for the woofer. These monitors are for low to medium volumes and when pushed hard, they tended to scream out with more upper midrange. With only 5-inch woofers, you are not going to fill the room with booming subsonics—get a subwoofer for checking that sub octave.

Another thing to consider:

For an instrument to sound good you must hear a balance of its high and low frequencies. If your room is too dead in the high frequencies the instrument sounds lifeless and tubby, whereas if it's too live in the high frequencies the instrument sounds distant and has no presence. To balance a room you must have a true balance of the high frequencies and the low frequencies with the right amount of deadness to liveness.

http://www.saecollege.de/reference_material/index.html Being that your room is:

11' 10" x 12' 5" room with textured 'popcorn' ceilings, carpted floor (almost shag), and textured drywall for walls.

it would be beneficial to add some degree of acoustic treatments to improve your sound. If you care to, you might want to check out a couple of posts addressing the acoustic treatment design and build, and the difference it made here: http://johnlsayers.com/phpBB2/viewtopic ... ght=#15598 and here: http://johnlsayers.com/phpBB2/viewtopic.php?t=4091 The treatments are based on the principles outlined throughout this forum and at the SAE website: http://www.saecollege.de/reference_material/index.html Here's a good link for some DIY units: http://johnlsayers.com/HR/index1.htm Hope these help. Looking forward to your progress. Aloha 8)

Alphaone - if you check out the reverb calculator here http://www.saecollege.de/reference_mate ... m#verbcalc you'll see that the AREA of absorption is also important. In your plan you have four corner absorbers that in reality don't offer much area of absorption to make much difference to the whole room area. cheers john

Thanks for those links guys..very useful information. I am really thinking now that I am going to return those foam traps and build from John's designs here http://www.johnlsayers.com/HR/index1.htm That said, I do have some questions regarding the corner and side wall absorbers. I was wondering in John's design with the varying slot widths and slat widths if this was ment to broaden the freq absorption? And if so what frequencies would it be if it were built to the ceiling and followed the design on that page? Also, is it necesarry to build from floor to ceiling with these? I downloaded the Helmholtz excel calculator, but it didn't specify the overall HxWxL of the absorber or if that even matters. kendale I noticed in your construction thread they didn't go all the way to the ceiling, so thats why I ask. It looks great by the way ...nice work. Another, possible problem is the hall and closet doors (actually and the window as well). I could however split the rear wall absorber and place them on the walls on either side of the closet door. Any thoughts? Suggestions? Thanks again.

Aloha,

I was wondering in John's design with the varying slot widths and slat widths if this was meant to broaden the freq absorption?

quote from http://www.saecollege.de/reference_material/index.html

If the gaps vary say 5mm, 10mm, 15mm,20mm and the wall is angled as shown below, a broad band low mid absorber is created that still keeps the the high frequencies alive. Remember the cavity behind must be sealed to an airtight container, like the bottle.

And if so what frequencies would it be if it were built to the ceiling and followed the design on that page?

I would guess same low-mid (200Hz-800Hz -ish) frequencies as above, just more absorption.

Also, is it necesarry to build from floor to ceiling with these?

Depends on your space available/problem frequencies/budget

kendale I noticed in your construction thread they didn't go all the way to the ceiling, so thats why I ask.

The reasoning in my case is that I am in a "temporary" location and wanted something portable to take with me in the event that a free standing studio building on our property becomes a reality. :D As it stands, "portable" weighs in at about 50-75 lbs a piece. :shock: By the way, even though they are only 4' x 8" x 43" the improvement to the sound of the room is quite remarkable.

Another, possible problem is the hall and closet doors (actually and the window as well).

Does your hall door open into the room or out?

I could however split the rear wall absorber and place them on the walls on either side of the closet door.

If you have the floorspace, you might want to consider two 4' x 8" x 7' floor standing units, as this is where a lot of your bass is building up. Here's a diagram for John's rear wall absorber: http://www.johnlsayers.com/HR/index1.htm and a "finished room with absorbers" Hope these help get the creative juices flowing. Aloha 8)

Hello, I took some time to rethink the layout a bit. In this design instead of using slats like in John's DIY Wall Units I used cloth front absorbers. The bass traps in the corners would have 4" insulation on all sides while the front, back, and side absorbers would have 4" insulation in the front all with cloth fronts. The traps in the back lect would be movable so I can get in and out of the room. Same goes for the back wall absorber, but that could be made in two seperate halves. Oh, one thing to note is that the monitors are on stands now instead of the desk. Also, the furniture I have in there will have to stay until I can find a place for them in another room. I don't know if this will greatly affect anything. Alternatively, I could do a rectangular absorber in the back identical to the one behind the mix position instead of the angled. A few concerns: 1.) By using all cloth covered absorbers will this be too much absorption? I've heard you can never have too much bass absorption, but I am concerned about mids and highs in particular. 2.) The side panels are angled, but I am not sure that it is enough to make a difference in breakign up the parallel walls. Sloping from 8" to 4" over 6.5 ft or so. Should I bother angeling them or make them straight like the front? (Note: Absorbers stick out 8" from the wall with closed backs just like John's design.) If this is a bad idea, I can just stick to Jonh's design, but this way without the slats is more economical for me. Thanks again.

Oh, I also wanted to post the results from the room modes excel calc.

Aloha,

the furniture I have in there will have to stay until I can find a place for them in another room. I don't know if this will greatly affect anything.

I am in a similar situation. I have a large wall unit that I am not able to remove at all. I was advised:

Left/right room symmetry (at least within a foot or two of ear height) is important for good stereo imaging, and that glass-faced cabinet can't be helping... For your application, a movable panel about 4" thick would help the wall unit "disappear" acoustically - it could be moved against a wall somewhere when not in use. Same for the front wall (behind the speakers) - and again behind you, if that's a glass surface.

In light of that, would something like this be viable for you? (At least until you can relocate your entertainment center?) Aloha 8)

how bout somethin like this making the front half of the room permanent and the back half movable to access all doors and windows when room is not in use

Hmm. I really like both of those suggestions. However, in the interest of selling the house later I don't think can make anything permanent. So, my other option would be to make everything portable. I like that layout Dreamin....really takes care of the parallel walls. I am wondering if this can still be achieved with gobos. Previousely I stated slots maye be out of the question, but after re-evaluating I may be able to still go with slots. However, I would want them to be broadband w/ varying slot and slat widths, but I have read in other threads that it averages out in the end. http://johnlsayers.com/phpBB2/viewtopic.php?t=5476&highlight=etf

knightfly wrote:

In any given slat absorber, changing width of boards and slots won't do as much as it seems, because the wavelengths involved are larger than the boards. This means that the entire absorber will "average" - doesn't mean it won't work, just means you won't know exactly what you did whether it's good or bad :? One way around this is to place "separators" inside the trap to segregate the space into individual chambers, making (in effect) several small helmholtz traps in one box. IF you do this, then making different sections within the same "box" would widen the range of frequencies the trap works at - it's also more of a PITA to build... Steve

So I was wondering does anyone have a link to plans for a slat absorber with the seperate chambers? I would like to make sure it will be broadband as I don't need to tune to a specific frequency. If anyone has any experience with these please let me know. Thanks.

So nobody knows or has plans on how to build a broadband slat absorber w/ seperators? :?

Aloha, I seem to vaguely remember a post quite sometime ago, possibly about a year or so ago. Perhaps if you did a "search" on the topic it would prove helpful. Aloha 8)