Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 619 - AVS Forum | Home Theater Discussions And Reviews
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post #18541 of 20530 Old 04-26-2016, 08:57 AM
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What I did was to move a single sub around the room to all available locations and run a sweep at each location.

Overlay all of the sweeps you gathered and choose the two best responses. If none of the responses look especially flat, choose two that will compliment each other (one dips where the other peaks and vice-versa).

Place the two subs in those locations and run Audyssey. Then confirm with a final measurement that the two locations work well together.
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post #18542 of 20530 Old 04-26-2016, 09:13 AM
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Quote:
Originally Posted by Alan P View Post
I agree with Jerry. The red curve would be the easiest to EQ flat and doesn't have the large nulls the other curves have.
Quote:
Originally Posted by Alan P View Post
What I did was to move a single sub around the room to all available locations and run a sweep at each location.

Overlay all of the sweeps you gathered and choose the two best responses. If none of the responses look especially flat, choose two that will compliment each other (one dips where the other peaks and vice-versa).

Place the two subs in those locations and run Audyssey. Then confirm with a final measurement that the two locations work well together.
Thanks Alan for confirmation. It is clear now.
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post #18543 of 20530 Old 04-26-2016, 09:46 AM
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Originally Posted by systemlayers View Post
Thanks that makes sense. I don't have a ton of flexibility for sub placement, can probably do 3 spots. Do I do crossovers first (without moving subs yet) or does it really matter what order I do that in?
I suggest determining the best location for your sub(s) first. Doesn't make a lot of sense to experiment with crossovers until you've found the best low frequency response for your given speakers and room. Don't forget that adjusting your L and R speakers could also make a difference near the XO region. I'd also suggest using the room mode calculator to help decide placement. If you're not familiar then just search this thread for "room mode calculator". Plenty of discussion on interpreting results.
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post #18544 of 20530 Old 04-26-2016, 11:59 AM
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I suggest determining the best location for your sub(s) first. Doesn't make a lot of sense to experiment with crossovers until you've found the best low frequency response for your given speakers and room. Don't forget that adjusting your L and R speakers could also make a difference near the XO region. I'd also suggest using the room mode calculator to help decide placement. If you're not familiar then just search this thread for "room mode calculator". Plenty of discussion on interpreting results.
That calculator will work even for a non-square/rectangular room? I got the crossovers better and eliminated the current 80hz null but will know more on the weekend how the subs look/work at different positions and will post results. Thank you. At present for 2 channel sound I really like where my speakers are but since it's mostly a setup for multi-channel I will measure more for that.
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post #18545 of 20530 Old 04-26-2016, 01:00 PM
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This is off topic, please let me know if it's too far in the weeds for the thread.

A buddy is in the midst of constructing a wind chime array consisting of 30 aluminum tubes of various lengths and diameters. According to the plans, when struck each tube will produce a unique frequency and combined a soothing, melodious sound is anticipated.

A fabricator cut some tube lengths shorter or longer (1/16" - 1/32") than spec'd and the end result will produce tones not intended in the plans.

We discussed the possibility of using REW and UMIK-1 to measure the unique frequency of each tube and what my buddy terms 'overtones' produced after striking an individual tube.

Would anyone kindly weigh in on the feasibility of measuring the unique frequency/overtone of each tube using REW/UMIK-1 setup on a table in an enclosed garage. My thought was suspending each tube one at a time nearfield to the mic and then measuring its output when struck.

Don't know if REW has the capability of measuring a discrete frequency using an outside 'source', in this case manually striking each tube one at a time. If it does, I'm happy to read REW's doc to understand how to perform the 30 measurements; if not, I'd appreciate if someone mention it to prevent us jumping into a rabbit hole.

Thank you.

Last edited by bmcn; 04-26-2016 at 06:06 PM.
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post #18546 of 20530 Old 04-26-2016, 02:32 PM
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This is off topic, please let me know if it's too far in the weeds for the thread.

A buddy is in the midst of constructing a wind chime array consisting of 30 aluminum tubes of various lengths and diameters. According to the plans, when struck each tube will produce a unique frequency and combined a soothing, melodious sound is anticipated.

A fabricator cut some tube lengths shorter or longer (1/16" - 1/32") than spec'd and the end result will produce tones not intended in the plans.

We discussed the possibility of using REW and UMIK-1 to measure the unique frequency of each tube and what my buddy terms 'overtones' produced after striking an individual tube.

Would anyone kindly weigh in on the feasibility of measuring the unique frequency/overtone of each tube using REW/UMIK-1 setup on a table in an enclosed garage. My thought was suspending each tube one at a time nearfield to the mic and then measuring the response.

Don't know if REW has the capability of measuring a discrete frequency using an outside 'source', in this case manually striking each chime one at a time. If it does, I'm happy to read REW's doc to understand how to perform the 30 measurements; if not, I'd appreciate if someone mention it to prevent us from jumping into a rabbit hole.

Thank you.
Definitely way out in the weeds. The only tool in REW that measures real time frequencies is the Real Time Analyzer. So, you can plug in the mic and open the RTA tool. The first thing you will notice is that the mic is picking up all sounds in the area real time, which makes for a pretty noisy output. For a test, I took a wine glass and tapped it with a spoon, which makes the wine glass resonate at a specific frequency. Here is what I see:



Based on this simple test, it seems that the wine glass has a fundamental frequency of ~600Hz, with harmonics at 1200Hz, 1800Hz, etc. If you are looking for precision, I don't see a way to read the actual fundamental frequency other than eyeballing it, which isn't going to be too accurate. You need to decide whether this approach is useful or not. Or perhaps someone else will come up with a better idea.
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post #18547 of 20530 Old 04-26-2016, 03:13 PM
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Definitely way out in the weeds.
Jerry, thanks; a closed garage isn't quite an anechoic room. Probably a non-starter, but you pointed me in the right direction using RTA. I appreciate it very much and it's about time to ping a wine glass anyway.
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post #18548 of 20530 Old 04-26-2016, 03:32 PM
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Originally Posted by bmcn View Post
Jerry, thanks; a closed garage isn't quite an anechoic room. Probably a non-starter, but you pointed me in the right direction using RTA. I appreciate it very much and it's about time to ping a wine glass anyway.
Based on my wealth of experience, the resonant frequency changes as the glass is filled up.
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post #18549 of 20530 Old 04-26-2016, 03:35 PM
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Based on my wealth of experience, the resonant frequency changes as the glass is filled up.
May your glass runneth over.
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post #18550 of 20530 Old 04-26-2016, 03:59 PM
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Originally Posted by Alan P View Post
What I did was to move a single sub around the room to all available locations and run a sweep at each location.

Overlay all of the sweeps you gathered and choose the two best responses. If none of the responses look especially flat, choose two that will compliment each other (one dips where the other peaks and vice-versa).

Place the two subs in those locations and run Audyssey. Then confirm with a final measurement that the two locations work well together.
Thanks,
What sweep should I run? Just the sub?

I guess leaving it at whatever level it is already set at is fine as long as it stays the same for each location. I probably don't need to worry about distance either if I'm just doing the sub by itself right?

New question: does position have much affect on the decay time in the room? Should I just position the subs for best frequency response and then worry about decay (room treatments) later?
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post #18551 of 20530 Old 04-26-2016, 04:08 PM
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Thanks,
What sweep should I run? Just the sub?

I guess leaving it at whatever level it is already set at is fine as long as it stays the same for each location. I probably don't need to worry about distance either if I'm just doing the sub by itself right?

New question: does position have much affect on the decay time in the room? Should I just position the subs for best frequency response and then worry about decay (room treatments) later?
Yes, run a sub-only frequency sweep 15-300Hz and display it with no smoothing. Trim and delay settings have no effect on a single-sub measurement. Resonances are standing waves based on room dimensions. The location of the sub should have no impact on resonance. Position the sub for smoothest frequency response. Interactions among multiple subs makes the whole exercise more complicated.
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post #18552 of 20530 Old 04-26-2016, 05:34 PM
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Definitely way out in the weeds. ...

Based on this simple test, it seems that the wine glass has a fundamental frequency of ~600Hz, with harmonics at 1200Hz, 1800Hz, etc. If you are looking for precision, I don't see a way to read the actual fundamental frequency other than eyeballing it, which isn't going to be too accurate. You need to decide whether this approach is useful or not. Or perhaps someone else will come up with a better idea.
Is it possible to use a sweep to find the sympathetic resonances of the chimes? Have REW do a sweep and look for frequency where the peak is higher than expected?

Definitely an interesting diversion from the topic
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post #18553 of 20530 Old 04-26-2016, 06:09 PM
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Is it possible to use a sweep to find the sympathetic resonances of the chimes? Have REW do a sweep and look for frequency where the peak is higher than expected?

Definitely an interesting diversion from the topic
Why don't you try that and report back your results?
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post #18554 of 20530 Old 04-26-2016, 06:59 PM
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Originally Posted by bmcn View Post
Jerry, thanks; a closed garage isn't quite an anechoic room. Probably a non-starter, but you pointed me in the right direction using RTA. I appreciate it very much and it's about time to ping a wine glass anyway.
You don't even need REW, just any DAW + spectrum analyser. You click Record, ping your chime and capture whatever is going on.
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post #18555 of 20530 Old 04-27-2016, 03:00 AM
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You don't even need REW, just any DAW + spectrum analyser. You click Record, ping your chime and capture whatever is going on.
Will take a look at Audacity. Thanks, dt.
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post #18556 of 20530 Old 04-27-2016, 08:06 AM
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Thanks,
What sweep should I run? Just the sub?

I guess leaving it at whatever level it is already set at is fine as long as it stays the same for each location. I probably don't need to worry about distance either if I'm just doing the sub by itself right?

New question: does position have much affect on the decay time in the room? Should I just position the subs for best frequency response and then worry about decay (room treatments) later?
Quote:
Originally Posted by AustinJerry View Post
Yes, run a sub-only frequency sweep 15-300Hz and display it with no smoothing. Trim and delay settings have no effect on a single-sub measurement. Resonances are standing waves based on room dimensions. The location of the sub should have no impact on resonance. Position the sub for smoothest frequency response. Interactions among multiple subs makes the whole exercise more complicated.
Jerry is spot on with his answer.
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post #18557 of 20530 Old 04-27-2016, 10:35 AM
 
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I'm planning to treat my room. I just had my room finished. Its 12x7.25x19.58. I posted the question before but didn't get any response. So hoping someone will help me out this time. I can ask in other threads but the beauty being on this thread is that if anyone is telling me what to do here, he knows it works because most likely he tested it with REW to see before/after impact.

After reading in different threads, its a common agreement to
1 - Cover Front wall completely with 1" linacoustic.
2 - Cover Top/Left/Right wall with 1" linacoustic up to where the front speakers will be placed.

Then handle first reflection. For that I'm going to hang panel that I made using 2" Fiber Glass on side wall. For celing I'll be using 4" Roxul mineral wool. I'll be taking before/after reading to see the difference in
frequency/decay/impulse.

Now comes the low frequencies. I made my own bass traps using two layers of 4" Roxul mineral wool. So basically, 8" of Roxul mineal wool covering corners. How effective is it? Well when I took reading, it made FR better.
But I have been reading around one one issue that's catching my eye is that these Home Made bass traps will not only absorb low but also high frequency which can make room sound dull.

I'd like to know if its worth/better to buy commercial bass traps like this one http://realtraps.com/p_mondotrap.htm? Also, how can I tell using REW that the room is over damped? Using Impluse, one can see if there is too much reflection (anything going above 20) but is there a way to know if room is too damped?

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post #18558 of 20530 Old 04-27-2016, 10:42 AM
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For multiple subwoofers should I mostly measure them in equal locations? I have 2 so would I measure - front corners, back corners and mid walls front and back? Or is it sometimes preferable to have 1 sub front left corner and 1 sub right mid wall for example and I should measure those possibilities as well?
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post #18559 of 20530 Old 04-27-2016, 10:51 AM
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For multiple subwoofers should I mostly measure them in equal locations? I have 2 so would I measure - front corners, back corners and mid walls front and back? Or is it sometimes preferable to have 1 sub front left corner and 1 sub right mid wall for example and I should measure those possibilities as well?
You should measure ALL possibilities if you want to get the most from your subs.

Just a few posts up from this, I posted this in response to a similar question:

Quote:
What I did was to move a single sub around the room to all available locations and run a sweep at each location.

Overlay all of the sweeps you gathered and choose the two best responses. If none of the responses look especially flat, choose two that will compliment each other (one dips where the other peaks and vice-versa).

Place the two subs in those locations and run Audyssey. Then confirm with a final measurement that the two locations work well together.
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post #18560 of 20530 Old 04-27-2016, 12:39 PM
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Originally Posted by SherazNJ View Post
I'm planning to treat my room. I just had my room finished. Its 12x7.25x19.58. I posted the question before but didn't get any response. So hoping someone will help me out this time. I can ask in other threads but the beauty being on this thread is that if anyone is telling me what to do here, he knows it works because most likely he tested it with REW to see before/after impact.

After reading in different threads, its a common agreement to
1 - Cover Front wall completely with 1" linacoustic.
2 - Cover Top/Left/Right wall with 1" linacoustic up to where the front speakers will be placed.

Then handle first reflection. For that I'm going to hang panel that I made using 2" Fiber Glass on side wall. For celing I'll be using 4" Roxul mineral wool. I'll be taking before/after reading to see the difference in
frequency/decay/impulse.

Now comes the low frequencies. I made my own bass traps using two layers of 4" Roxul mineral wool. So basically, 8" of Roxul mineal wool covering corners. How effective is it? Well when I took reading, it made FR better.
But I have been reading around one one issue that's catching my eye is that these Home Made bass traps will not only absorb low but also high frequency which can make room sound dull.

I'd like to know if its worth/better to buy commercial bass traps like this one http://realtraps.com/p_mondotrap.htm? Also, how can I tell using REW that the room is over damped? Using Impluse, one can see if there is too much reflection (anything going above 20) but is there a way to know if room is too damped?

The approach to treatments that I would recommend is to use REW to measure your room response characteristics. Use the ETC measurement to assess specular reflections, and the waterfall to assess bass resonance. There are general guidelines for reflections (lower all reflections in the first 20ms to -20dB or lower), and bass resonance (no persistent ringing in the first 20dB below the peak measurement level).

Once you have made an assessment of where your issue are, then develop a plan to address the issues with judicious selection and placement of treatments. Bass traps in corners where walls intersect, and broadband traps in places that reduce measured reflections.

IMO, RealTraps make a fine product, but at a premium price. After purchasing my first set of RealTraps bas traps, I moved on to GIK Acoustics, which make an equally good product at a much lower price.
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post #18561 of 20530 Old 04-27-2016, 01:05 PM
 
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IMO, RealTraps make a fine product, but at a premium price. After purchasing my first set of RealTraps bas traps, I moved on to GIK Acoustics, which make an equally good product at a much lower price.
Thx Jerry. GIK has many bass trap and no way to compare them to explain how they differ. Which bass trap did you get?


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The approach to treatments that I would recommend is to use REW to measure your room response characteristics. Use the ETC measurement to assess specular reflections, and the waterfall to assess bass resonance. There are general guidelines for reflections (lower all reflections in the first 20ms to -20dB or lower), and bass resonance (no persistent ringing in the first 20dB below the peak measurement level).

Once you have made an assessment of where your issue are, then develop a plan to address the issues with judicious selection and placement of treatments. Bass traps in corners where walls intersect, and broadband traps in places that reduce measured reflections.
This is exactly what I did. My first goal is to find the best Frequency response for subs. I want to get the best response for subs. When I started with nothing but Subs in room, there were many peaks and a few nulls. Then I stacked my own built bass trap (8" RockWool panels) in front corners and FR got much better. Even before I look into controlling room ringing and delay, I want to get a good FR for my subs and Mains.

One of the concerns I have is over damping room. I have no idea how to know if its over damped? before I had 1" linacoustic covering whole front wall and side will up to where front speakers are. How do I know if its not over damping the room? Many say it should be there but no one showed (or I couldn't find) what it really does using graph.
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post #18562 of 20530 Old 04-27-2016, 04:00 PM
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Thx Jerry. GIK has many bass trap and no way to compare them to explain how they differ. Which bass trap did you get?



This is exactly what I did. My first goal is to find the best Frequency response for subs. I want to get the best response for subs. When I started with nothing but Subs in room, there were many peaks and a few nulls. Then I stacked my own built bass trap (8" RockWool panels) in front corners and FR got much better. Even before I look into controlling room ringing and delay, I want to get a good FR for my subs and Mains.

One of the concerns I have is over damping room. I have no idea how to know if its over damped? before I had 1" linacoustic covering whole front wall and side will up to where front speakers are. How do I know if its not over damping the room? Many say it should be there but no one showed (or I couldn't find) what it really does using graph.
As for the GIK products, there are not that many choices in bass traps. There are two types of panels, 244's and Monster Bass Traps. I have 20 244 panels and 2 Monster Bass Traps. There are also soffit traps and corner traps, which are essentially just a different form factor. If you scroll down to the bottom of a product page, you can find a link to the technical product details. Here is an example.

I don't know how to advise you on whether your room is over-treated or not. A listening test is a good idea. My approach has been to identify specific reflections, and use a treatment to eliminate them. As for covering an entire wall without a specific reason to do so would not be my approach. If you are having difficulty making the right decisions, consider hiring an acoustic consultant.
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post #18563 of 20530 Old 04-27-2016, 08:55 PM
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Quote:
Originally Posted by SherazNJ View Post
I'm planning to treat my room. I just had my room finished. Its 12x7.25x19.58. I posted the question before but didn't get any response. So hoping someone will help me out this time. I can ask in other threads but the beauty being on this thread is that if anyone is telling me what to do here, he knows it works because most likely he tested it with REW to see before/after impact.



After reading in different threads, its a common agreement to

1 - Cover Front wall completely with 1" linacoustic.

2 - Cover Top/Left/Right wall with 1" linacoustic up to where the front speakers will be placed.



Then handle first reflection. For that I'm going to hang panel that I made using 2" Fiber Glass on side wall. For celing I'll be using 4" Roxul mineral wool. I'll be taking before/after reading to see the difference in

frequency/decay/impulse.



Now comes the low frequencies. I made my own bass traps using two layers of 4" Roxul mineral wool. So basically, 8" of Roxul mineal wool covering corners. How effective is it? Well when I took reading, it made FR better.

But I have been reading around one one issue that's catching my eye is that these Home Made bass traps will not only absorb low but also high frequency which can make room sound dull.



I'd like to know if its worth/better to buy commercial bass traps like this one http://realtraps.com/p_mondotrap.htm? Also, how can I tell using REW that the room is over damped? Using Impluse, one can see if there is too much reflection (anything going above 20) but is there a way to know if room is too damped?




You can pick up a roll of pink floor protection paper at HD for $6 IIRC, or heavy duty craft paper or something similar. Try adding something like that to the surface of your panels or reduce high frequency absorption.

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post #18564 of 20530 Old 04-28-2016, 06:32 AM
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You can pick up a roll of pink floor protection paper at HD for $6 IIRC, or heavy duty craft paper or something similar. Try adding something like that to the surface of your panels or reduce high frequency absorption.
While I agree that this approach is likely to reduce HF absorption, it may create random unwanted reflections as a result. That would mean analyzing where the reflections are coming from and treating those spots to eliminate them. IOW, and endless loop.

I still think a better approach is to avoid brute-force methods, analyze specific problem areas, and address them with spot solutions. This is less likely to result in an over-treated room that sounds dead, which is what the OP is trying to avoid. And, of course, there is the unanswered question--how do we tell if the room has been over-treated? AFAIK, the only way is to listen--if it sounds dead, you probably have gone too far.
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post #18565 of 20530 Old 04-28-2016, 08:28 AM
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While I agree that this approach is likely to reduce HF absorption, it may create random unwanted reflections as a result. That would mean analyzing where the reflections are coming from and treating those spots to eliminate them. IOW, and endless loop.

I still think a better approach is to avoid brute-force methods, analyze specific problem areas, and address them with spot solutions. This is less likely to result in an over-treated room that sounds dead, which is what the OP is trying to avoid. And, of course, there is the unanswered question--how do we tell if the room has been over-treated? AFAIK, the only way is to listen--if it sounds dead, you probably have gone too far.
Agreed to a degree. You suggested that he buys bass traps from GIK, and I suggested an easy low cost alternative that he can test on his existing traps. Perhaps you think DIY is a fools errand and that's your prerogative, but I'm not sure how putting a piece of paper onto the trap traps him in an endless loop or brute force. Ultimately he will need to measure and listen to decide when he has achieved his goal. Paper is only one high frequency reflector option but it cheap and easily reversible - there are also plenty of simple low cost DIY options to decrease high frequency absorption using 1/16-1/8" pieces of wood as well but those would require a tad more work and some tools. For example, he could use pegboard available from HD and add slots of varying lengths, cut up a piece 1/8" hardboard from HD into furring strips and arrange them in a slightly randomized pattern across the front of the trap for partial reflections, etc. Ordering a panel from GIK is of course easier, but it's not necessarily better nor easily customized. More importantly, if he cut one open he very well might find some hardboard panels across the front just like I am suggesting.

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post #18566 of 20530 Old 04-28-2016, 09:36 AM
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Agreed to a degree. You suggested that he buys bass traps from GIK, and I suggested an easy low cost alternative that he can test on his existing traps. Perhaps you think DIY is a fools errand and that's your prerogative, but I'm not sure how putting a piece of paper onto the trap traps him in an endless loop or brute force. Ultimately he will need to measure and listen to decide when he has achieved his goal. Paper is only one high frequency reflector option but it cheap and easily reversible - there are also plenty of simple low cost DIY options to decrease high frequency absorption using 1/16-1/8" pieces of wood as well but those would require a tad more work and some tools. For example, he could use pegboard available from HD and add slots of varying lengths, cut up a piece 1/8" hardboard from HD into furring strips and arrange them in a slightly randomized pattern across the front of the trap for partial reflections, etc. Ordering a panel from GIK is of course easier, but it's not necessarily better nor easily customized. More importantly, if he cut one open he very well might find some hardboard panels across the front just like I am suggesting.
A slight correction. The OP said he was considering purchasing bass traps from RealTraps, and I simply suggested that if he were purchasing ready-made treatments, that he give GIK Acoustics a look. I don't believe I said or implied that DIY is a fools errand. I have a number of friends and fellow AVS participants who have completed very successful DIY projects, and I have nothing but respect for their efforts and results.
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post #18567 of 20530 Old 04-28-2016, 12:55 PM
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So I did some playing around and found what seemed to be good positions for my subs. Then I messed around with subs+LR and found the 100hz x-over to look pretty good for the bass. After all that I ran Audyssey to at one position for the levels and distances. Then I re-measured. The post Audyssey looks a lot worse to me.

Purple is prior to running Audyssey. The 2 different green lines are post Audyssey one is lfe and the other is lfe+mains. I thought the names would be shown when I captured the graph.

All graphs are with Audyssey OFF

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post #18568 of 20530 Old 04-28-2016, 01:17 PM
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So I did some playing around and found what seemed to be good positions for my subs. Then I messed around with subs+LR and found the 100hz x-over to look pretty good for the bass. After all that I ran Audyssey to at one position for the levels and distances. Then I re-measured. The post Audyssey looks a lot worse to me.

Purple is prior to running Audyssey. The 2 different green lines are post Audyssey one is lfe and the other is lfe+mains. I thought the names would be shown when I captured the graph.

All graphs are with Audyssey OFF
When doing a screen capture, click the "Include Legend" option to identify the measurements. Also, it looks like the graphs have smoothing applied. Always present low frequency graphs with no smoothing.

I am not understanding your claim that the post-Audyssey measurement looks worse, especially since you say Audyssey is turned off. A more reasonable comparison would be "before Audyssey" and "after Audyssey". Can we see that comparison?
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post #18569 of 20530 Old 04-28-2016, 01:28 PM
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So I did some playing around and found what seemed to be good positions for my subs. Then I messed around with subs+LR and found the 100hz x-over to look pretty good for the bass. After all that I ran Audyssey to at one position for the levels and distances. Then I re-measured. The post Audyssey looks a lot worse to me.

Purple is prior to running Audyssey. The 2 different green lines are post Audyssey one is lfe and the other is lfe+mains. I thought the names would be shown when I captured the graph.

All graphs are with Audyssey OFF
I agree with what Jerry said.

What subs, how many subs, and what version of Audyssey are you using?

Also, if one of the green lines is LFE and the other is LFE+Mains....how did you measure LFE+Mains? Did you use output channels 1 & 2 with bass management? If so, why isn't the LFE only trace 10dB higher than the LFE+Mains trace??

It does look like that after Audyssey you somehow developed a significant dip at 40hz. This is quite odd since there was no dip pre-Audyssey. Are you certain nothing else changed between the two measurements? Even moving the measurement mic a few inches can make a significant difference.



EDIT: I wanted to also add that a single point Audyssey calibration is usually not going to provide Audyssey with enough info to properly EQ your response. I would suggest at least 3 mic positions at the bare minimum, but using all 8 is always best.
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post #18570 of 20530 Old 04-28-2016, 01:44 PM
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I agree with what Jerry said.

What subs, how many subs, and what version of Audyssey are you using?

Also, if one of the green lines is LFE and the other is LFE+Mains....how did you measure LFE+Mains? Did you use output channels 1 & 2 with bass management? If so, why isn't the LFE only trace 10dB higher than the LFE+Mains trace??

It does look like that after Audyssey you somehow developed a significant dip at 40hz. This is quite odd since there was no dip pre-Audyssey. Are you certain nothing else changed between the two measurements? Even moving the measurement mic a few inches can make a significant difference.



EDIT: I wanted to also add that a single point Audyssey calibration is usually not going to provide Audyssey with enough info to properly EQ your response. I would suggest at least 3 mic positions at the bare minimum, but using all 8 is always best.
Alan, remember that Audyssey is turned off for all measurements. While the OP didn't specifically say so, it looks like he started with trims and distances in the AVR all set to zero. He then ran the single-point Audyssey calibration only to establish trims and distances. AFAIK, simply changing trims and distances doesn't guarantee a better response curve. What we need to see is a measurement with Audyssey ON in order to assess whether Audyssey is doing the expected, i.e. improving the overall frequency response.

Otherwise, the measurements are meaningless.
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