Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 410 - AVS Forum
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post #12271 of 12292 Old 11-24-2014, 06:09 AM
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Quote:
Originally Posted by markus767 View Post
Try to get a used Onkyo TX-NR818. It came with XT32.
A second sub will probably improve things the most.
You're in luck, they have one left:
http://www.accessories4less.com/make...eceiver/1.html
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post #12272 of 12292 Old 11-24-2014, 08:53 AM
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Originally Posted by markus767 View Post
The man's name is Floyd Toole.
Apologies. So Toole, Olive and Geddes are the spiritual leaders of this thread?

Quote:
Originally Posted by markus767 View Post
Other than that treating the back wall is a very good idea especially when one is sitting close to it.
One other thing. I found that my panel's ETC measured a little better when slightly separated. So, instead of 12' of contiguous panels the panels have a 10" gap between them. More gap or less gap was worse.
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post #12273 of 12292 Old 11-24-2014, 09:37 AM
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Originally Posted by AustinJerry View Post
Unfortunately, due to the shape of your room, and the sloping ceiling, I am not sure that this helps very much. It does show that you have a first-order standing wave at 47Hz associated with the length of the room. Moving the couch forward may alleviate this somewhat. You seem to be sitting pretty far away from the screen. How large is that screen? And the distance to the left and right speakers could be closer to the equilateral triangle if you move the couch forward.
Here are a couple pictures of my our family room that I posted before on the other thread. Till a month ago this used to be what we called the "mud room." My wife's happy to have the TV/speakers out of the living room, and I'm sure happy to be able to crank my music after the kids go to be since I'm now on the opposite side of the house.





The pictures were taken before I put up 2' x 3' 4" absorption panels on either side of the couch as well as the clouds. I also put heavier polyester blackout curtains up. Come to think of it, I should measure the ETC with the curtains open and closed to see if this really made any difference. My ears tell me a little.

I will try moving the couch up, but it would be a awkward to do this more than a foot. I know it is not considered great to have the couch so close to the wall. I may actually consider putting a panel behind the curtains in font of the window. I will measure this. Assuming the ETC is what to look at here? My main thought though is still to build two 2' x 4' 4" absorption panels on either side of the back wall. I will try angling them out a bit to create the air pocket back there. Or I also am considering framing them with a 6" width wood so a air pocket will be created that way. Not sure if that's enough space to do much good.

The way I'm thinking now, I will most likely look at another PB-1000 sub in the next few months. Seems most people here think this will make the most difference, which makes sense to me. My only hesitation is that the corner to the right seems to be such a crappy place to put a sub that I do wonder if this could be counterproductive. Still, my thinking is that this would make more of a difference to SQ than moving to XT32. (Of course I'm sure some people might look at that picture and think I'm out of my mind to consider a second sub with a TV that old, but hey, I'm more of a music guy than movie. A new TV will come too.)

This week I will definitely try out the blocking technique when I spare moment. Thanks for that, Jerry. And thank you to everyone who has helped me here.
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Last edited by Greenwood Ave; 11-24-2014 at 09:42 AM.
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post #12274 of 12292 Old 11-24-2014, 09:42 AM
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One of the many nice things about SVS is that you can try it and return it if it doesn't work out.
Instead of replacing your AVR, you might want to add a parametric equalizer to the subwoofer output. I used to use this one:
https://www.google.com/webhp?hl=en&t...=en&q=dsp1124p
Should still be available used at Guitar Center and other places.

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http://www.avsforum.com/t/1475769/de...ently-authored 

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post #12275 of 12292 Old 11-24-2014, 09:51 AM
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Quote:
Originally Posted by LastButNotLeast View Post
One of the many nice things about SVS is that you can try it and return it if it doesn't work out.
Instead of replacing your AVR, you might want to add a parametric equalizer to the subwoofer output. I used to use this one:
https://www.google.com/webhp?hl=en&t...=en&q=dsp1124p
Should still be available used at Guitar Center and other places.
Would that work well used in addition to Audyssey XT? That link isn't working for me for some reason.
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post #12276 of 12292 Old 11-24-2014, 10:26 AM
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Yes. You need the other EQ for the other speakers; this just goes to the subs.
Here's one:
http://www.musicgoroundlincoln.com/p...r-feedback-pro

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post #12277 of 12292 Old 11-24-2014, 11:05 AM
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Dunno if this posting by Dr. Olive has been mentioned here:

A Method For Training Listeners and Selecting Program For Listening Tests

Listener Performance Is Strongly Influenced by Program SelectionThe single largest effect on the listener’s performance was the program selection. Slide 13 plots the mean listener performance scores for each of the twenty programs averaged across all eight equalizations. The percentage of correct responses ranged from a high of 88% (pink noise) to a low of 54% (jazz piano trio). Listeners performed the task best when using broadband, spectrally dense continuous signals like pink noise or pop/rock selections like Tracy Chapman, Little Feat, and Jennifer Warnes. Listeners performed worse on programs featuring solo instruments, small combos and speech that produced more discontinuous and narrow band signals. More about this later.
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post #12278 of 12292 Old 11-24-2014, 01:36 PM
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Quote:
Originally Posted by Greenwood Ave View Post
Here are a couple pictures of my our family room that I posted before on the other thread. Till a month ago this used to be what we called the "mud room." My wife's happy to have the TV/speakers out of the living room, and I'm sure happy to be able to crank my music after the kids go to be since I'm now on the opposite side of the house.


The pictures were taken before I put up 2' x 3' 4" absorption panels on either side of the couch as well as the clouds. I also put heavier polyester blackout curtains up. Come to think of it, I should measure the ETC with the curtains open and closed to see if this really made any difference. My ears tell me a little.

I will try moving the couch up, but it would be a awkward to do this more than a foot. I know it is not considered great to have the couch so close to the wall. I may actually consider putting a panel behind the curtains in font of the window. I will measure this. Assuming the ETC is what to look at here? My main thought though is still to build two 2' x 4' 4" absorption panels on either side of the back wall. I will try angling them out a bit to create the air pocket back there. Or I also am considering framing them with a 6" width wood so a air pocket will be created that way. Not sure if that's enough space to do much good.

The way I'm thinking now, I will most likely look at another PB-1000 sub in the next few months. Seems most people here think this will make the most difference, which makes sense to me. My only hesitation is that the corner to the right seems to be such a crappy place to put a sub that I do wonder if this could be counterproductive. Still, my thinking is that this would make more of a difference to SQ than moving to XT32. (Of course I'm sure some people might look at that picture and think I'm out of my mind to consider a second sub with a TV that old, but hey, I'm more of a music guy than movie. A new TV will come too.)

This week I will definitely try out the blocking technique when I spare moment. Thanks for that, Jerry. And thank you to everyone who has helped me here.
I think you need to pause and think about all the suggestions you have received, and especially not make any big purchases or put up any new treatments without a specific game plan.

For example, when you placed the treatments on the side walls, did you determine their exact placement using a mirror?

Next, only place a treatment on the back wall if it provides a measurable difference in the reflections. With that window directly behind you, you may not have any reflections to correct.

Third, with respect to moving the couch forward, we are not asking you to commit to anything permanent. We are asking you to simply take several measurement with the mic placed in front of the MLP, more towards the front of the room, without moving the couch. If those measurements show a significant reduction in the 50Hz issue, then you can decide if the improvement warrants moving the couch.

Fourth, you have heard from several people now that an additional sub (placed properly) is likely to produce the most improvement. Consider this purchase before upgrading your AVR to XT32. Both are significant expenses, and you want the most bang for the buck (if improved bass is your objective).

And finally, if you decide on getting an inexpensive DSB unit, I strongly recommend the MiniDSP, which is less than $150, simply because there is a large community here on AVS that can help you configure it properly.
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post #12279 of 12292 Old 11-24-2014, 01:51 PM
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Originally Posted by AustinJerry View Post
Probably, but to address the 50Hz peak, you would need to re-position the sub, add another sub, or add treatments. So we are really saying the same thing, no?
My point was that I don't believe he's using any sort of EQ so applying a cut there would reduce the initial impulse and thus reduce the ringing.

EDIT: Now I feel like Keith...should've turned on the now infamous "read ahead mode".

Last edited by jkasanic; 11-24-2014 at 01:58 PM.
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post #12280 of 12292 Old 11-24-2014, 01:59 PM
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I think you need to pause and think about all the suggestions you have received, and especially not make any big purchases or put up any new treatments without a specific game plan.
+1
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post #12281 of 12292 Old 11-24-2014, 03:55 PM
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Originally Posted by AustinJerry View Post
I think you need to pause and think about all the suggestions you have received, and especially not make any big purchases or put up any new treatments without a specific game plan.
I hear you, Jerry. I agree with everything you've said, and I certainly didn't mean to come off like I was ignoring anyone's advice.

Quote:
For example, when you placed the treatments on the side walls, did you determine their exact placement using a mirror?
Yes, I did use a mirror. I did hit two of the sidewall first reflection points with the panels, but due to the window on one side and the edge of the wall on the other, perhaps I didn't hit them as squarely as might be desirable.

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Next, only place a treatment on the back wall if it provides a measurable difference in the reflections. With that window directly behind you, you may not have any reflections to correct.
I understand this and I definitely intend to measure... This actually brings up something else I was wondering about. I was initially thinking that people would mention the placement of the two windows as being a major problem in my room (one is directly on a sidewall first reflection point, and the other is directly behind my head). So far no one has mentioned the windows. Thinking about this more, I wonder if the windows, especially covered by heavy drapes, are better than drywall. The data I've seen suggests that below 1 kHz windows absorb more than drywall, and then perhaps the drapes on top do a better job on the frequencies above that. Does this sound about right?

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Third, with respect to moving the couch forward, we are not asking you to commit to anything permanent. We are asking you to simply take several measurement with the mic placed in front of the MLP, more towards the front of the room, without moving the couch. If those measurements show a significant reduction in the 50Hz issue, then you can decide if the improvement warrants moving the couch.
Makes perfect sense. I will try this.

Quote:
Fourth, you have heard from several people now that an additional sub (placed properly) is likely to produce the most improvement. Consider this purchase before upgrading your AVR to XT32. Both are significant expenses, and you want the most bang for the buck (if improved bass is your objective).
Completely agree with this. As I wrote above, I'm definitely leaning towards eventually going with a second sub. Although I'd like XT32, spending $500+ on another receiver isn't something I'm considering.

Quote:
And finally, if you decide on getting an inexpensive DSB unit, I strongly recommend the MiniDSP, which is less than $150, simply because there is a large community here on AVS that can help you configure it properly.
That is good to know you think a DSP might be useful. This may actually be the next place I put money. One thing about this, I know I asked this before, but just be clear, you don't see any complications on running the MiniDSP on the bass and then Audyssey on top of it? I seem to recall reading somewhere that this was not a good idea, but I suppose I can't think of any reason why it wouldn't be.

The only reason I brought up making the other bass traps was because I already have 4 sheets of Owens Corning 703 from a six pack I bought. I liked making the clouds, so I figure it couldn't hurt to put some panels in back or somewhere else that would hit a reflection point and perhaps make a small difference in the bass. I do understand that measuring everything carefully is sage advice.

Thank you again, Jerry. Both your advice here and your guide have been and continue to be very helpful to me.

Last edited by Greenwood Ave; 11-24-2014 at 04:07 PM.
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post #12282 of 12292 Old 11-24-2014, 05:10 PM
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Quote:
Originally Posted by Greenwood Ave View Post

That is good to know you think a DSP might be useful. This may actually be the next place I put money. One thing about this, I know I asked this before, but just be clear, you don't see any complications on running the MiniDSP on the bass and then Audyssey on top of it? I seem to recall reading somewhere that this was not a good idea, but I suppose I can't think of any reason why it wouldn't be.

The only reason I brought up making the other bass traps was because I already have 4 sheets of Owens Corning 703 from a six pack I bought. I liked making the clouds, so I figure it couldn't hurt to put some panels in back or somewhere else that would hit a reflection point and perhaps make a small difference in the bass. I do understand that measuring everything carefully is sage advice.
I have tried using a MiniDSP both before and after Audyssey. I think the danger lies when the DSP is trying to address a dip in the response. The DSP can add boost, and if it doesn't completely fix the dip, Audyssey can come along and add more boost, which can definitely cause issues. But your situation is a peak. Knocking a peak down is what a DSP is good at, and doesn't pose any danger, IMHO.

No harm placing treatments anywhere. Just measure the effectiveness, and move them around depending on the results.
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post #12283 of 12292 Old 11-24-2014, 07:48 PM
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Quote:
Originally Posted by AustinJerry View Post
If I could augment d00d's feedback a bit. When you are doing your measurements, there are several objectives.

Objective 1-Use REW to assess the performance of the subs by themselves, which includes moving the subs around to find the best placement. To configure REW for this objective, you need to turn off the main speakers (either by carefully disconnecting their cables, or by turning off your separate power amp, if you use one). Feed the AVR with a signal on both the left and right channels (HDMI 1and 2), and set the AVR to stereo mode. Run sweeps 15-300Hz, and present the results without any smoothing.

Objective 2-Assess overall bass performance, which will include the contributions of the left and right speakers, as well as the center. For these measurements, turn the left and right speakers back on, set the crossover to the normal value (say 80Hz), and take four measurements:

- With the AVR in stereo mode, feed the left channel (HDMI 1 in REW) and measure 15-300Hz. Present the results with no smoothing.

- Repeat for the right channel (HDMI 2 in REW).

- Feed the left and right channels simultaneously, and repeat the measurement a third time (measuring left and right channels)

- And finally, keeping both channels active in REW, change the AVR to PLII Cinema, which allows you to measure the center channel.

These four measurements will give you good insight into how the bass region is performing in your room with your equipment.

You can also run full sweeps 15-20,000 Hz for the left, right and center channel to see how the whole spectrum is being reproduced. These measurements should have smoothing applied (anywhere from 1/24 to 1/6, depending on who you talk to).

I took the measurements as per suggested steps
My interpretation from these measurements is that I need to do something about 20-40Hz region.
May be I need to first work on relocating the sub. (May be I can make use of some time this weekend)
Please see these measurements and hep me analyze.
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post #12284 of 12292 Old 11-24-2014, 10:15 PM
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Nice job with producing a representative set of measurements.

I think the most troubling thing is the dip at 50Hz that seems to be in most of the measurements. The strength of the 20-40Hz curve is troubling only because the bottom falls out at 50Hz, which must be audible. Analyzing raw measurements like these are difficult without some supporting details.

- Are you using EQ of any type, e.g. Audyssey? If Audyssey, which version? If yes, do the measurements represent Audyssey off or on?
- How many subs?
- Room dimensions?
- Location of sub(s)?
- Room pictures?

Ideally, you should have a relatively flat response, something like this:


Last edited by AustinJerry; 11-24-2014 at 10:23 PM.
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post #12285 of 12292 Old Yesterday, 01:03 AM
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Quote:
Originally Posted by aaranddeeman View Post
May be I need to first work on relocating the sub. (May be I can make use of some time this weekend).
Time for the subwoofer crawl:
http://www.audioholics.com/home-thea...ofer-placement

Downloadable FREE demo discs:
http://www.avsforum.com/t/1475769/de...ently-authored 

Did you really need to quote that entire post in your reply?
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post #12286 of 12292 Old Yesterday, 03:00 AM
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Quote:
Originally Posted by Greenwood Ave View Post
...

Completely agree with this. As I wrote above, I'm definitely leaning towards eventually going with a second sub. Although I'd like XT32, spending $500+ on another receiver isn't something I'm considering.

That is good to know you think a DSP might be useful. This may actually be the next place I put money. One thing about this, I know I asked this before, but just be clear, you don't see any complications on running the MiniDSP on the bass and then Audyssey on top of it? I seem to recall reading somewhere that this was not a good idea, but I suppose I can't think of any reason why it wouldn't be.

The only reason I brought up making the other bass traps was because I already have 4 sheets of Owens Corning 703 from a six pack I bought. I liked making the clouds, so I figure it couldn't hurt to put some panels in back or somewhere else that would hit a reflection point and perhaps make a small difference in the bass. I do understand that measuring everything carefully is sage advice.

Thank you again, Jerry. Both your advice here and your guide have been and continue to be very helpful to me.
Greenwood Ave,

I've got some experience using the MiniDSP 2x4 with Audyssey MutliEQ (one version down from XT) and one sub woofer. Having limited positions on where the sub can go and not being able to adjust the listening position meant that the results weren't that satisfactory. I've come to the conclusion that only a second sub is going to really help with the suck out that REW was showing.

The other problem I found out was that the peak above 200Hz couldn't really be dealt with using the LFE output of the receiver. With the limited filters available on MultiEQ, there really wasn't a good solution. Now looking at room treatments.

Maranatz NR1504, Oppo BPD-93, MTV 7000D, LG LW6500, aTV, WDTV Live, Harmony 650 remote, KEF E301, MiniDSP(2x4), Rythmik F12G
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post #12287 of 12292 Old Yesterday, 06:35 AM
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Quote:
Originally Posted by AustinJerry View Post
Nice job with producing a representative set of measurements.
Thanks...

Quote:
Originally Posted by AustinJerry View Post
I think the most troubling thing is the dip at 50Hz that seems to be in most of the measurements. The strength of the 20-40Hz curve is troubling only because the bottom falls out at 50Hz, which must be audible. Analyzing raw measurements like these are difficult without some supporting details.
Ah. I never would have thought about that.

Quote:
Originally Posted by AustinJerry View Post
- Are you using EQ of any type, e.g. Audyssey? If Audyssey, which version? If yes, do the measurements represent Audyssey off or on?
No Auddyssey, No EQ of any tpe while taking the measurements. Only level matched all speakers using SPL
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Originally Posted by AustinJerry View Post
- How many subs?
One Sub.
Quote:
Originally Posted by AustinJerry View Post
- Room dimensions?
17' x 11' (Plus a 2' wide niche in the front right, so front half is 8'x13 and rear half is 9'x11' approx)
Quote:
Originally Posted by AustinJerry View Post
- Location of sub(s)?
Sub is placed midway in that 2' x 8' niche.
Quote:
Originally Posted by AustinJerry View Post
- Room pictures?
I will try and get the sketch



Edit : Sorry, there is some mess-up with the quotes.
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post #12288 of 12292 Old Yesterday, 07:41 AM
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Here are the room modes. BTW, need ceiling height as well.



As you can see, the primary mode associated with the width is 51Hz. So, not sure based on your response, but the sub should be placed at exactly the center point of the width of the room. I assume your MLP is in the center of the width as well, meaning you are sitting in the middle of the mode, i.e. a low spot for 51Hz.
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post #12289 of 12292 Old Yesterday, 06:21 PM
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Quote:
Originally Posted by AustinJerry View Post
Nice job with producing a representative set of measurements.

I think the most troubling thing is the dip at 50Hz that seems to be in most of the measurements. The strength of the 20-40Hz curve is troubling only because the bottom falls out at 50Hz, which must be audible. Analyzing raw measurements like these are difficult without some supporting details.

- Are you using EQ of any type, e.g. Audyssey? If Audyssey, which version? If yes, do the measurements represent Audyssey off or on?
- How many subs?
- Room dimensions?
- Location of sub(s)?
- Room pictures?

Ideally, you should have a relatively flat response, something like this:

Quote:
Originally Posted by AustinJerry View Post
Here are the room modes. BTW, need ceiling height as well.



As you can see, the primary mode associated with the width is 51Hz. So, not sure based on your response, but the sub should be placed at exactly the center point of the width of the room. I assume your MLP is in the center of the width as well, meaning you are sitting in the middle of the mode, i.e. a low spot for 51Hz.

Thanks Jerry.
While I do some reading about the room modes (to make sense out of it), please see the room sketch.
The actual dimensions are
(L)17' 8" x (W)11' 6" (+ 2' at right front) x (H)7' 8"

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Edit : Just wanted to note here that the MLP (sofa) shown in the sketch is the current position. I have just repositioned it a few weeks back including dropping the surrounds to ear level (from earlier height of 6 feet) in preparation for Atmos (whenever that happens in my room). Prior to it, the MLP was about 2 feet behind from current.

Last edited by aaranddeeman; Yesterday at 09:02 PM.
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post #12290 of 12292 Old Today, 04:21 AM
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I have a new dedicated 2 chl space that I have been working on acoustically and am now getting up to speed with REW. Before I get to involved, I wanted to make sure the setup I’m using is correct (basically what the REW 101 setup guide states)

- Dayton Audio EMM-6 with a MIC Mate classic USB adapter (using the cal file I download from parts expressed based on the serial number )
- Laptop (Lenovo T410) Win7x64
- 3.5 mini to stereo RCA cable (laptop output/headphone jack)
- RCA female to female adapter
- Long stereo male to male RCA cable (to preamp)

All the above will connect into a L/R input on my dedicated analog preamp (parasound P7). I am just interested in 2-channel measurements and have a fair amount of treatment (703+705 broadband => first reflections, corners, cloud) in place. I am using 3-way towers with 2 subs and have spent a ton of time on speaker placement/symmetry (based on the 1/3 rule etc..)

I have run a few sweeps with REW just to get the ball rolling and it seem to be working, although during the sweeps the headroom “value” is red and shows 2-8db if I remember correctly. Is that a function of the laptop sound card level too high? Additionally, the instructions state "you will see a “Headroom” display. Normally, this value should be in the -25dB to -5dB range" but the graphic displays "13db" not "-13db" confusing -maybe I'm interpreting that wrong.

I also have no problem getting a different mic if my current "pseudo USB" mic will create issues.

Awesome thread and setup guides. This stuff is fascinating and really looking forward to correcting the issues I know my space has.
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post #12291 of 12292 Old Today, 06:25 AM
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No, you are correct. The guide should read 25 to 5 dB headroom. Thanks for pointing that out--I have made the correction.

As for whether you should get a new mic or not, keep in mind that many of us here use the USB mic with HDMI connections. This makes it easy to select channels in a 7.1 audio configuration. Since you have a two-channel audio system with a processor that doesn't support HDMI, I would say that your present kit is perfectly fine for your needs. You should be able to fully utilize the features of REW to analyze your system.
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post #12292 of 12292 Old Today, 06:44 AM
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Quote:
Originally Posted by 3ll3d00d View Post
asio4all is not really asio, it is an asio wrapper on kernel streaming. There is config, IIRC, in asio4all to decide whether to resample itself & whether automatic sample rate switching works depends on what it is talking to underneath. In my experience, it works just fine and there is no need to do anything other than set the sample rate in REW. What do you mean by "sweeps that were chopped" exactly? perhaps post an example?
Sorry for the delayed reply, time flew by.. Now I have plenty of time though, since I was laid off last week, dammit..

Here is an example of the chopped/corrupted audio. It's a crappy cell phone recording, but easy enough to hear the artifacts. The file was checked with VLC and MPC-HC.
http://www.jjaz.dk/privat/hifi/ASIO_Issue.amr

Source: HTPC
Pre: Marantz AV8801 + Pro Kit
PA: April Music Stello S200 (GD1 >130Hz), 2x ICEpower 1000ASP (GD1 <130Hz), 2x ICEpower ASP1000 (Subs), Marantz MM8077 (Rear+Center+Back)
Spkr: GD1 (Front), GDA125 (2xRear+1xBack), GDA Center (Center)
Subs: 4 towers, a total of 28 x 10" 25W ScanSpeak
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