etc6849 Posted February 28, 2015 Share Posted February 28, 2015 I've added some 4" acoustical foam from ats acoustics which really improved imaging for me. I can now easily pin point where instruments are forwards and backwards as well as from left to right. Questions: Looking at the graphs below, would I benefit from 8 corner and ceiling mounted bass traps too? I see decay issues below 200Hz, but should I really worry about these? What am I missing by leaving things as is? Is there some improvement in bass tightness I could achieve, and would it be worth $1k worth of bass traps from GIK or ATS Acoustics? Also, are the dips at 117.5 Hz and 314 Hz on the FR plot with no smoothing worth worrying about? They disappear with 1/6th smoothing, but they can't be room modes right since that frequency has a wavelength way bigger than my room, right? PS: the subs pictured are not the ones in the plot. I'm trying out some SVS PB13-ultras, but they are in the same location as the RT12d's. I removed the RT12d's from the room temporarily. 2 Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 28, 2015 Share Posted February 28, 2015 (edited) Hi Ellery. If you could, try posting your RT60 plot, found in the buttons just below the icons at the top center of the plot display. I've attached an RT60 plot for reference... The sharp nulls aren't a problem, and the 314 Hz is probably the height of the microphone above the floor, etc., so I'd not worry about that. Bass traps work down to about 70 Hz unless you stack them along the wall length wise end-to-end across the wall-floor or wall-ceiling boundary. Chris Edited February 28, 2015 by Chris A 2 Quote Link to comment Share on other sites More sharing options...
etc6849 Posted February 28, 2015 Author Share Posted February 28, 2015 (edited) Hi Chris, thanks for your help. So, it sounds like the response below 70 Hz can only be fixed by having a bigger room!?! I've read that large spaces don't have low frequency decay issues... I've also attached the REW file too, but had to zip it first. EDIT: Attached file is of the left P39f, with a crossover of 60 Hz to dual SVS PB13-ultras, using Audyssey Sub EQ HT via a pro kit and AV8801. Feb 27 23_05_09.zip Edited February 28, 2015 by etc6849 Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 28, 2015 Share Posted February 28, 2015 I'd try at least two corner traps (if you've got the corners) or alternatively along the canted-top ceiling chine space, and butt up against one wall (which drops the effective absorbed frequencies by an octave). The rise in the RT60 values in your plot above 100 Hz is what I'm looking at--making that recommendation. Chris 2 Quote Link to comment Share on other sites More sharing options...
etc6849 Posted February 28, 2015 Author Share Posted February 28, 2015 (edited) Thanks Chris. If I go with GIK Acoustics (they are the closest to me), it looks like soffit traps would be best as far as absorption. The corner trap doesn't appear to be as nearly effective. Too bad the things are $229 each! Now I remember why I ordered cheap foam. Any good plans for building standalone soffit traps that would have similar performance to those linked below? My plan is to mount the soffit traps in the front corners (44" high), along the back ceiling and back right corner opposite the door. I'm thinking I'd order or build 5 soffit traps in total. I plan to return the ATS Acoustics foam traps. http://www.gikacoustics.com/product/gik-acoustics-soffit-bass-trap/ EDIT: Also, has anyone ordered from GIK Acoustics? Edited February 28, 2015 by etc6849 1 Quote Link to comment Share on other sites More sharing options...
etc6849 Posted March 1, 2015 Author Share Posted March 1, 2015 (edited) Chris and others, Do you think I should run the subs in sealed mode (in green)? This appears to gain me a lot at 10 hz due to room gain. I'm losing some max spl, but I'll never play things at 110dB. Edited March 1, 2015 by etc6849 Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted March 1, 2015 Share Posted March 1, 2015 Thanks Chris. If I go with GIK Acoustics (they are the closest to me), it looks like soffit traps would be best as far as absorption. The corner trap doesn't appear to be as nearly effective. Too bad the things are $229 each! Now I remember why I ordered cheap foam. Any good plans for building standalone soffit traps that would have similar performance to those linked below? My plan is to mount the soffit traps in the front corners (44" high), along the back ceiling and back right corner opposite the door. I'm thinking I'd order or build 5 soffit traps in total. I plan to return the ATS Acoustics foam traps. http://www.gikacoustics.com/product/gik-acoustics-soffit-bass-trap/ EDIT: Also, has anyone ordered from GIK Acoustics? Have you considered making your own? It only cost me $60 for the RT60 to make 3 panels as i recall 4" thick...plus the wood and fabric. If you can afford to buy by all means do, but if you are cash strapped and can handle a hammer or screwdriver and glue you can make your own pretty easily. Quote Link to comment Share on other sites More sharing options...
Arash Posted March 1, 2015 Share Posted March 1, 2015 have you ever tried Dirac Live DRC? Quote Link to comment Share on other sites More sharing options...
OO1 Posted March 1, 2015 Share Posted March 1, 2015 I've added some 4" acoustical foam from ats acoustics which really improved imaging for me. I can now easily pin point where instruments are forwards and backwards as well as from left to right. Questions: Looking at the graphs below, would I benefit from 8 corner and ceiling mounted bass traps too? I see decay issues below 200Hz, but should I really worry about these? What am I missing by leaving things as is? Is there some improvement in bass tightness I could achieve, and would it be worth $1k worth of bass traps from GIK or ATS Acoustics? Also, are the dips at 117.5 Hz and 314 Hz on the FR plot with no smoothing worth worrying about? They disappear with 1/6th smoothing, but they can't be room modes right since that frequency has a wavelength way bigger than my room, right? PS: the subs pictured are not the ones in the plot. I'm trying out some SVS PB13-ultras, but they are in the same location as the RT12d's. I removed the RT12d's from the room temporarily. FR full.jpg FR full no smoothing.jpg waterfall 400hz.jpg waterfall full.jpg floor plan.jpg floor plan2.jpg theater front.JPG theater back.JPG what class is the acoustic foam you used - Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted March 1, 2015 Share Posted March 1, 2015 Those are some nice speakers. Get the wires out of the floor so no one trip and breaks one of the speakers. It will happen sooner or later. 1 Quote Link to comment Share on other sites More sharing options...
etc6849 Posted March 1, 2015 Author Share Posted March 1, 2015 Class A. It's made in the US too. I wasn't going to trust the Chinese stuff. what class is the acoustic foam you used - Quote Link to comment Share on other sites More sharing options...
etc6849 Posted March 1, 2015 Author Share Posted March 1, 2015 There's no easy way for me to try it without changing my preamp out right? have you ever tried Dirac Live DRC? 1 Quote Link to comment Share on other sites More sharing options...
OO1 Posted March 1, 2015 Share Posted March 1, 2015 Class A. It's made in the US too. I wasn't going to trust the Chinese stuff. what class is the acoustic foam you used - great - you chose wisely - expensive for sure but worth it and fire-proof - dont forget to add a bit of ventilation as foam is a chemical agent - Quote Link to comment Share on other sites More sharing options...
Arash Posted March 1, 2015 Share Posted March 1, 2015 There's no easy way for me to try it without changing my preamp out right? have you ever tried Dirac Live DRC? to use Dirac Live you have to have a PC as an Audio source. just download the Trial version and you only need a measurement microphone you probably have. IMO Dirac Live acoustic correction will make the sound A WHOLE LOT better. Quote Link to comment Share on other sites More sharing options...
etc6849 Posted March 1, 2015 Author Share Posted March 1, 2015 (edited) I'll give it a try, thanks! The only bad side to it I see is I could no longer bit stream DTS and Dolby formats. I'd have to let my PC do all decoding. This would mean I would never use the Neo X and PLIIx modes on my preamp. EDIT: dang, the full version of the software is $732?!? to use Dirac Live you have to have a PC as an Audio source. just download the Trial version and you only need a measurement microphone you probably have. IMO Dirac Live acoustic correction will make the sound A WHOLE LOT better. Edited March 1, 2015 by etc6849 1 Quote Link to comment Share on other sites More sharing options...
artto Posted March 1, 2015 Share Posted March 1, 2015 (edited) I've added some 4" acoustical foam from ats acoustics which really improved imaging for me. I can now easily pin point where instruments are forwards and backwards as well as from left to right. Questions: Looking at the graphs below, would I benefit from 8 corner and ceiling mounted bass traps too? I see decay issues below 200Hz, but should I really worry about these? What am I missing by leaving things as is? Is there some improvement in bass tightness I could achieve, and would it be worth $1k worth of bass traps from GIK or ATS Acoustics? There is almost no such thing as "too much" bass trapping. The problem associated with it has to do with too much absorption in the middle & upper frequencies. If that becomes a problem you could put some kind of panel over the front of them so they reflect the higher frequencies. The longer wavelengths of bass frequencies won't "see" the panel and the bass traps will still be effective as bass traps. Your room looks like it already has quite a bit of absorption, maybe even more than it needs with all the non-parallel surfaces. Bass trapping is most effective in corners. The width, depth and height/length of the bass trap is also important as it relates directly to how low in frequency the trap will be effective. Think of it this way. Just as the Khorn benefits from it's design taking advantage of 1/8 space (trihedral corner) to produce lower frequencies and higher output bass, so does a bass trap in the opposite way. I recently extended my Auralex MegLNRD's to full floor to ceiling 8' tall bass traps (as opposed to just one or two stacked in each corner) and the difference was quite amazing. Edited March 1, 2015 by artto 1 Quote Link to comment Share on other sites More sharing options...
etc6849 Posted March 2, 2015 Author Share Posted March 2, 2015 (edited) Thanks everyone. I called GIK acoustics and spoke with their acoustic engineer/part owner Bryan. He pretty much stated what ChrisA and artto stated. I provided him a new REW file (with FL, FR and sub), and since the left and right channels don't have the 1xx hz and 3xx hz issues (visible with no smoothing) in the same place, he stated they weren't room modes. He said not to worry about them as they are only a few hz wide, but that it's likely due to the hollow core door (closet or entry) letting energy through them, and that a monster trap on the back door might fix some of it. He said that since the room was L shaped that the diagonal response is different for the left and right channel, and this is why the frequency dips are slightly different for each. However, he said due to the frequencies of musical notes, those frequencies would not make a difference to listening. He did recommend 2-4 soffit traps be placed in the room and stated they are their best absorbers and good down to ~35 Hz! He also said to ensure 40dB of data was visible on the waterfall plots (something I was doing wrong). When we did that, we noted some frequencies that decayed longer than 300 ms. He did say my response plot was very good, and that it was actually surprisingly good. In fact, he even said any studio would kill to have my response! I guess dual subs and Audyssey subEQ HT are really worth it after all. Overall, he said my room looked good as is, but if I want to improve things bass traps will do that. He also stated another useful fact: RT60 plots are typically only used for large rooms. It would appear for small rooms acousticians use waterfall plots. Another thing I learned was to use y-cables when plotting response to get a plot with all channels driven. He said this will show if there's any cancellation between the left and right speakers. Something that's apparently common. Too bad REW doesn't let you do that over an HDMI connection. I know these soffit traps will improve the decay times, but I'm satisfied with the sound I have now. Bryan probably wasn't a good sales person, but was very honest. He never said I'd hear a drastic difference, and even stated that 2, no more than 4, soffit traps is all he would put in my room. I'm going to think about ordering a couple. Edited March 2, 2015 by etc6849 Quote Link to comment Share on other sites More sharing options...
Arash Posted March 5, 2015 Share Posted March 5, 2015 (edited) I'll give it a try, thanks! The only bad side to it I see is I could no longer bit stream DTS and Dolby formats. I'd have to let my PC do all decoding. This would mean I would never use the Neo X and PLIIx modes on my preamp. EDIT: dang, the full version of the software is $732?!? to use Dirac Live you have to have a PC as an Audio source. just download the Trial version and you only need a measurement microphone you probably have. IMO Dirac Live acoustic correction will make the sound A WHOLE LOT better. yes that's right. btw, there is also IKMultimedia ARC2 DRC system which works fantastic. it's a package with a calibrated mic and two parts of software. one for measuring and a VST plugin which works in sound mixing editors. but it also works in players like Foobar2000 and Jriver. it's 300USD. if you have a calibrated mic I can help you use it for free. just drop me a pm and I'll tell you what to do notice: in my opinion digital room correction works best combining with acoustic room treatment. Edited March 5, 2015 by Arash Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 5, 2015 Share Posted March 5, 2015 How did you determine you needed any treatment at all? The vaulted ceiling is not parallel to anything in the room. It looks like you have way too much treatment. You should need hardly any at all by the looks of things. Maybe something on the back wall to prevent "slap"...............and maybe a couple of bass traps but I doubt it really. Treating a room is the one audio mystery to me...............Less is more in my book. I admit I never quite figured out how what makes things optimal. How should the plot look? The risk is you add too much and it becomes a dead room. Sure.........it sounds clearer..........but it's dead otherwise. You should have the trailing edge of cymbals dancing off the ceiling. Quote Link to comment Share on other sites More sharing options...
etc6849 Posted March 6, 2015 Author Share Posted March 6, 2015 (edited) The recording should already have the cymbals dancing off the ceiling (if it was recorded in a live room), so what's the point of having my room compound this? Are we not trying to reproduce what the audio engineer heard? Some engineers use headphones any ways, so you can bet the material already sounds the way it should. More clarity and better imaging is what I like about room treatments. I really don't see that as a bad thing. I also don't think my room is too dead, and I honestly think it sounds great. You should have the trailing edge of cymbals dancing off the ceiling. Edited March 6, 2015 by etc6849 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.