jrios212 Posted January 9, 2007 Share Posted January 9, 2007 hi guys, i've done some research on this sight and the general consensus seem to be to start with the rear of the room for bass traps. i currently only have enough for two corners (also have pyramid foam) so wanted to get your thoughts on where i should start. i'll do some experimenting but, again, wanted to get someones initial thoughts. the only reason i'm thinking i might want to put them in the front of my room is because the back of my room already has these triangle shapes coming out the corners and i feel like that may be helping. this maybe the wrong approach, but i put some bass heavy music on and walked back there and couldn't really hear the bass getting any louder (building up) back there. if anything it seems to build up in the front corners, but that just might be because i'm closer to the sub. any thoughts? jacob Quote Link to comment Share on other sites More sharing options...
jrios212 Posted January 9, 2007 Author Share Posted January 9, 2007 the front of my room. oh .. the dimensions are 22 x 11 with 9 foot ceilings. the speakers are on the short wall. Quote Link to comment Share on other sites More sharing options...
Parrot Posted January 9, 2007 Share Posted January 9, 2007 What problem are you experiencing that you think you need bass traps in the first place? I doubt if you need any. Quote Link to comment Share on other sites More sharing options...
jrios212 Posted January 9, 2007 Author Share Posted January 9, 2007 i've got a dip of around 8-10db around the 80-125hz range. maybe my speakers just don't go that low even though the website indicates it. DrWho mentions "boundary cancellation"a lot. The backs of my speakers are about 16" away from theback wall and the fronts of my speakers are about 27" away from theback wall. To me this seems like I'd experience boundarycancellation starting around 125hz so i don't think that's the problem. 1130/x= 9; therefore x= 125 1130 = speed of sound | 9 = distance of speaker from wall(2.25)*4 here's some measurements i took. my crossover is at 80hz, which i can't change. my sub is turned up a bit higher than it should be i know. frequency spl 20 82 25 87 31.5 83 40 80 50 86 63 78 80 64 100 62 125 65 160 72 200 77 250 76 315 73 400 74 500 74 630 72 800 72 1000 74 1250 75 1600 76 2000 75 2500 77 3150 76 4000 77 5000 77 6300 80 8000 81 10000 73 12500 70 16000 69 20000 68 it's not that big of deal. i like the way things sound but since i have the foam i thought i'd give it a try. thanks for the thoughts, jacob Quote Link to comment Share on other sites More sharing options...
Parrot Posted January 9, 2007 Share Posted January 9, 2007 it's not that big of deal. i like the way things sound but since i have the foam i thought i'd give it a try. Jacob, The key thing is that you like the way things sound now. This is a case of if it ain't broke, don't fix it. I don't put any faith in those kinds of frequency checks--they lead to listener dissatisfaction [] Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 9, 2007 Share Posted January 9, 2007 For starters, you might find these links helpful:http://www.ethanwiner.com/acoustics.htmlhttp://forums.klipsch.com/forums/thread/796165.aspxhttp://www.acoustics101.com/default.asphttp://www.prosoundweb.com/install/sac/sup27/part1/mesp2.shtmlhttp://www.prosoundweb.com/install/sac/sup27/part2/ppam.php Itdoesn't sound like you have any measuring equipment (ratshack meter +test tones isn't going to suffice) - so doing it by ear is just goingto take longer. However, some guys have been getting this (free)program to work with their ratshack meter:http://www.hometheatershack.com/roomeq/- all you'd need is a computer with a decent soundcard. The HTS forumswill be very helpful in getting you set up and running (don't forget toread the stickys and setup manual first). Anyways, putting basstraps in areas where there is no bass buildup isn't going to have anyeffect. In my limited experience with bass traps, I've always ended upputting them in the front of the room - each room is different and theproblem areas are going to move around. The idea is that you want toabsorb the reflections that are causing the dips in the frequencyresponse, as well as reducing the length of resonating frequencies.Foam bass traps need to be large to be effective at lower frequencies,so don't expect them to do much below 50,60Hz...I would imagine withproper placement that your 100Hz-ish issues should get resolved. Butas always - try your best to make things sound as good as you can bymoving the speakers around and tweaking the crossover settings on thesub. I wrote an article that addresses some tricks I've picked up alongthe way for doing this by ear (that way I don't gotta keep repeatingmyself): []Dial in a Subwoofer By Ear One thing you might consider is trying to listen a bit more inthe near-field of the speakers. The boundary cancellation effects areonly going to occur at frequencies where the dispersion is wide enoughto actually bounce off the wall. Pulling the speakers out and away fromthe walls and moving the cancellation to frequencies below thecrossover point will dramatically reduce the effects. It also puts youcloser to the direct sound, making it louder in comparison to thereflected sounds in your room while increasing the time length betweenthe direct sound and the first reflection in the room. The frequencyresponse is but one view of behavior that moves around in time. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted January 9, 2007 Share Posted January 9, 2007 How long you going to be there? Assume your in school right? Might make sense to worry more about it when you buy a house, otherwise its like buying your first grade school sweet heart a wedding ring. Quote Link to comment Share on other sites More sharing options...
Islander Posted January 9, 2007 Share Posted January 9, 2007 Are you using a CD and an SPL meter to get those numbers? I'd like to find a CD with test tones that cover most of the audio range. The only one I have just covers the range from 10Hz-200Hz, which is fine for setting up the sub, but I'd like to get an in-room response curve for my speakers. Is anyone aware of a CD or DVD that has test tones (not sweeps) from 20-20KHz? Quote Link to comment Share on other sites More sharing options...
jrios212 Posted January 9, 2007 Author Share Posted January 9, 2007 How long you going to be there? Assume your in school right? Might make sense to worry more about it when you buy a house. actually i graduated college in '03. just moved from austin (where i own a house) to chicago. i'll probably only be here until the fall and then will hopefully be headed to business school on the west coast. but you're right, i'll definitely put more thought into things when i finally settle back in a house. for now i'm just messing around. Quote Link to comment Share on other sites More sharing options...
jrios212 Posted January 9, 2007 Author Share Posted January 9, 2007 yup .. here's the cd i used along with an spl meter. (stereophile editor's choice cd) http://www.stereophile.com/features/853/ i haven't used it in awhile as i'm trying not to get too caught up in measurments but it's definitely a cool (actually nerdy) thing to try. Are you using a CD and an SPL meter to get those numbers? I'd like to find a CD with test tones that cover most of the audio range. The only one I have just covers the range from 10Hz-200Hz, which is fine for setting up the sub, but I'd like to get an in-room response curve for my speakers. Is anyone aware of a CD or DVD that has test tones (not sweeps) from 20-20KHz? Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted January 9, 2007 Share Posted January 9, 2007 hi guys, i've done some research on this sight and the general consensus seem to be to start with the rear of the room for bass traps. i currently only have enough for two corners (also have pyramid foam) so wanted to get your thoughts on where i should start. i'll do some experimenting but, again, wanted to get someones initial thoughts. the only reason i'm thinking i might want to put them in the front of my room is because the back of my room already has these triangle shapes coming out the corners and i feel like that may be helping. this maybe the wrong approach, but i put some bass heavy music on and walked back there and couldn't really hear the bass getting any louder (building up) back there. if anything it seems to build up in the front corners, but that just might be because i'm closer to the sub. any thoughts? jacob Hi jacob Bass Traps are most effective when used in the corners of a room because all room modes terminate in the room corners. In most situations it would also be best to use bass traps in the front corners first because you will also be cleaning up the room sound/reflection interferance at the earliest point in time after the initial sound from the loudspeaker. Room modes basically ring and carry on long after the initial sound has ended which causes a loss of clarity and I've yet to be in a home listening room that couldn't benefit from bass traps. Some people have the false idea that bass traps will absorbe the bass and cause a perceived loss of bass SPL but actually when done correctly your perception will be a stronger/tighter Bass/MidBass response in your room with greater clarity because the room response wil be smoother and better damped. Here is a site with some good articles explaining some of the problems with rooms and room modes. http://www.acousticsciences.com/index.htm mike tn[] Quote Link to comment Share on other sites More sharing options...
johnyholiday Posted January 9, 2007 Share Posted January 9, 2007 Just messen around, how about the Rice banner high up in the corner ,one banner groment tacked to the wall with the A/C register, the other banner groment tacked to the wall that is behind the TV,forming a triangle,johny hates 90 degree corners,stuff with favorite acoustic condiments Quote Link to comment Share on other sites More sharing options...
jrios212 Posted January 9, 2007 Author Share Posted January 9, 2007 ha ..i hadn't thought of that. that could look decent actually. Quote Link to comment Share on other sites More sharing options...
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