View Full Version : Acustic treatment advise. Room Dimensions and REW graph included!


longfellowfan
01-28-07, 03:08 PM
I started playing with the Rew and it is pretty cool I played with my phase and this is as flat as I could get it. I hear bass traps could help flatten the graph. I have read alot on ethan web site and other and pretty sure they will but I am a amateur at this audio stuff. My sub is a SVS PB-10 My Room dimensions are 16x11x8 with two openings on the south wall. One open is a standard door frame and the other is like a opening in the middle of the wall that looks from the living room to the Kitchen. It Measures 4 1/2' wide and 3 1/2 foot wide. My wife has approved two 2'x2'x2" panels at the first reflection points. She has also approved one of the following three 2'x4'x4" thick or two 2'x4'x6" thick bass traps for corner placement from the ceiling tri-corner down with more to come if she call hear the difference. All treatment will be diy with a pine frame around Owen Corning 703 2" thick layered for the traps covered in Gom. My signiture has some general pics of my living room/HT will update pics this week along with more REW graphs including one up to 20,000hz. Also my sub was placed using the crawl for bass method from audioholics and my seating position and measurements were taken 4 ft from the back wall. I would like to move it up 2 more ft for the 38% rule I have read about but baby steps for my wife who is more supportive than I could ever hope for.
Here (http://www.youtube.com/user/stlfdemt) IS A LINK FOR A 360 degree view of my living room

longfellowfan
01-28-07, 03:22 PM
I just noticed I spelled Acoustic wrong. Sorry, told you I am new at this.

cyberbri
01-28-07, 03:44 PM
What about corner wedges?

Something like the Tri-Traps that GIK Acoustics offers. That may blend in with your room much better, and because of the design it works like a thicker 6"~ panel.

Here's what one looks like, and they could be stacked to the ceiling:
http://www.gikacoustics.com/images/TriTrap1.jpg

They're a bit more complicated to build, because of the frame and cutting the fiberglass into triangle wedges. But it may work better for you.

I look forward to seeing your progress. That's great you worked it out with your wife. I have similar panels, although I bought mine, and my wife has been great about "allowing" them in the room (see my gallery). I am considering building some of the corner wedge traps myself sometime...



HTH

longfellowfan
01-28-07, 03:51 PM
I actually showed my wife your photo gallery so she would know I was not the only one who cares about great audio. I am considering making the corner wedge ones but my wife said no not until we get a different house with a dedicated Home Theatre then will probably do them floor to ceiling on all 4 corners.
Also new full spectrum graph added

bpape
01-29-07, 06:59 AM
If hearing a difference is the key to proceeding with treating the room more appropriately, then go for the 3 4" panels. The additional surface area willl give more broadband control - but each one won't go quite as deep.

Also, the 6" panels you discussed will take the same amount of material (703) that the solid chunks will.

Bryan

JimP
01-29-07, 07:46 AM
Those hardwood floors are beautiful, but I can't help believe that they're a problem sound wise.

Try this. Stand in the middle of your room and clap your hands. Do you hear an echo?

My point is (provided you hear the echo) that this may not be a good room to spend money on traps unless you can do something about that floor. You are likely to find that heavy drapes and thick carpet to be a much more effective improvement and one that your wife would go along with.

longfellowfan
01-29-07, 09:24 AM
Those hardwood floors are beautiful, but I can't help believe that they're a problem sound wise.

Try this. Stand in the middle of your room and clap your hands. Do you hear an echo?

My point is (provided you hear the echo) that this may not be a good room to spend money on traps unless you can do something about that floor. You are likely to find that heavy drapes and thick carpet to be a much more effective improvement and one that your wife would go along with.
No slap echo that I can hear. We added a 12'x8' carpet since those photos were taken. I think I will shoot a small video with my digital camera and maybe put it on youtube if I can. That away people can get a 360 degree view of my living room. I will try to have that up on Wednesday.
Also Bryan thanks for the advise I think I will go with the 4" panels and maybe later placing those out of the corner and put superchunks in.

JimP
01-29-07, 09:30 AM
No slap echo that I can hear. We added a 12'x8' carpet since those photos were taken. I think I will shoot a small video with my digital camera and maybe put it on youtube if I can. That away people can get a 360 degree view of my living room. I will try to have that up on Wednesday.
Also Bryan thanks for the advise I think I will go with the 4" panels and maybe later placing those out of the corner and put superchunks in.

Might have helped if you had mentioned that carpet earlier on. :D

Do you know what frequencies are a problem?

eugovector
01-29-07, 10:23 AM
I just noticed I spelled Acoustic wrong. Sorry, told you I am new at this.

If you edit your first post, I think it will give you the option to change your thread title. Probably a good idea.

Kal Rubinson
01-29-07, 10:42 AM
Do you know what frequencies are a problem?Just look at his full-range sweep measurement. Compared with a relatively flat 800-2KHz range, he has a broad 20dB(!) hump centered on 6KHz and a broad 15-20dB depression across the 40-150Hz range. He seems to need a large amount of broad-band absorption to tame the upper range and, in doing so, that may ameliorate the bass problems. If not, that can be attacked afterwards in a number of ways.

cyberbri
01-29-07, 12:25 PM
Also new full spectrum graph added


You need to try that again at a much higher level, like 75dB baseline. It may look much different. But at the very least you could probably turn up your sub a lot (15~20dB), which would help with the dip. And what meter/software are you using? Not all mics are accurate above 4K or so, so you may not actually have a big rise up high. Do you know if your mic is accurate throughout the freq range or not?



And BTW, I took some more pics last night. I'll be updating my gallery tonight. It's not drastically different, though. Just shows the current state of things.

For me, I'm lucky my wife is understanding and indulges me. But I see it like this: if I buy a nice suit, I'd want a nice tie and pair of shoes to go with it. I wouldn't go without a tie and just wear flip-flops with the suit. Without the shoes and the tie, a suit looks bad. It doesn't live up to its potential. Or in a wife's case, buying a nice new black dress, but pairing it with a non-matching bag and a pair of tennis shoes. So for me, now that I have experienced audio with proper room treatments, I know that going without them is not letting the equipment that I spent my hard-earned cash on live up to its potential. Like I said, I'm lucky my wife is as understanding as she is. :D

longfellowfan
01-29-07, 05:36 PM
I am using the radio shack sound meter and Room EQ free software. I am still trying to hit the target of 70 db. I am using a MacBook and must use the line in. I know the 20 to 200hz is accurate because I used it with realtraps free test cd and graph and it is the same as the Eq software from home theatre shack. I have calibrated my system and I do listen to my sub 8db hot to compensate for the dip. Finally In the first post I will ad a link to my living room video on youtube.

cyberbri
01-29-07, 05:54 PM
The RS meters aren't good past 4K or so, so don't worry about the response up there. That's what mine looked like too when I did it:
http://www.hometheatershack.com/forums/bfd-rew-forum/3133-rew-rs-digital-meter-strange-results-high-freqs.html

http://www.hometheatershack.com/forums/attachments/bfd-rew-forum/1840d1169541819-rew-rs-digital-meter-strange-results-high-freqs-20hz-filter-3_new-speaker-positions_20k_1-3.jpg

Is that dip because of phase issues? Have you tried reversing the phase switch on the sub, assuming you set the speaker and sub distances in your receiver?

How did you calibrate to get the sub level and know where 8dB hot is? Because at least from the full-range graph, 500~2KHz looks like it's at 50dB, while the sub range is about 30dB. So the sub could still be cold. Try a 15Hz~2KHz sweep, experiment, etc.

And which meter do you have? Analog? Digital? Are you using the correct .cal file? The rise below 40Hz looks like it's more due to the compensation, like maybe you're using the wrong .cal file possibly.


At any rate, that sub response means you're a good candidate for some bass traps, plus an eq. Assuming you've already experimented with sub placement to find the best/smoothest location already.


ADD:
Just checked out your video on YouTube. Have you tried putting the sub in the rear right corner (where the DVDs are) or the rear left (where the lamp is)? That might help a lot with the response and with the SPL level.

longfellowfan
01-29-07, 07:50 PM
I used my receiver test tones to calibrate. I have the analog meter and used the cal file for that model. Also I have placed the sub every-wear in the room and that was the best response. I will get about 3 hrs of free time tomorrow and will play with the room-eq. Thanks for the advise so far from all of you.

longfellowfan
01-30-07, 10:27 AM
Here is a new graph I did this morning with better calibration closer to the target area for what it is worth.

cyberbri
01-30-07, 12:47 PM
Looks great.

Did you try reversing the phase on the sub? That big drop between 70 and 90Hz looks like it could be from phase issues.

longfellowfan
02-05-07, 09:55 AM
With the help of my wonderful assistant,my wife, we did some new measurements and now have my sub tuned and in phase. Here are two graph showing the results. I am still planing my room treatments when my Tax money comes from Uncle sucker. :D Thanks again for everyone's help. Also feel free to comment on the new measurements.