Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 58 - AVS Forum
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post #1711 of 12050 Old 03-01-2013, 08:51 AM
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JD - it's my understanding that the mode calculator is pretty much useless for those of us with open floorplans.
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post #1712 of 12050 Old 03-01-2013, 09:06 AM
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Originally Posted by Alan P View Post

JD - it's my understanding that the mode calculator is pretty much useless for those of us with open floorplans.
Oh well. It was a nice dream while it lasted. Thanks.

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post #1713 of 12050 Old 03-01-2013, 09:43 AM
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Originally Posted by Alan P View Post

JD - it's my understanding that the mode calculator is pretty much useless for those of us with open floorplans.

 

Not necessarily.  Any of these models are approximations designed to help us address room response issues.  I have an open floor plan as well.

 

The first step in the process is to measure the listening area's frequency response, 15-20,000Hz.  Looking at the measurement, you should look at several of the worst peaks and/or dips, and note the frequency range in which they occur.  These peaks/dips are the result of interactions with rooom modes.  The question is, which room modes?

 

Next step is to pick a room length, width, and height to enter into the standing wave calculator (download a copy here).  For the room length, I would measure from the wall where the TV is to the bak wall where the stairs are.  For width, I would measure from the wall with the couch to the wall where the left surround is placed.  When you enter these values into the calculator, see if any of the calculated room modes match up with the peaks/dips in your frequency measurement.  If yes, then you can use this information to experiment with placements to see if you can get any improvement.

 

If none of the calculated standing waves align with the measurements, you can try entering the room width as the width of the entire open space, and see if any calculated standing waves match the measurements.

 

If you still can't get the calculations to match up with measurements, there are still general guidelines that you can follow for speaker and sitting locations.  Place speakers at 1/4 and 3/4 positions across the front wall, or at 1/6 and 5/6.  Place these speakers 1/8 of the length away from the front wall.  etc.

 

The point is, experiment with placement, and measure!

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post #1714 of 12050 Old 03-01-2013, 09:55 AM
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I stand corrected! Thanks Jerry.
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post #1715 of 12050 Old 03-01-2013, 10:17 AM
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Pres, just to clarify, the length of the room is usually entered, and referred to as the dimension from the screen to the back wall. I'm getting a little mixed up when I read the posts in terms of length and width. I think you are saying that the main listening position is against the back wall at the midpoint and that back wall has a dimension of 18.5'. That would mean the width of your room is 18.5', not 10.5'. Is that correct?

I guess you can say the long wall is the width in this case; however, I've always veiwed the long side of the room as the lenght. I suppose it doesn't really matter, like Jerry said.

EDIT: Angryht, I can see what you mean. Do I move the couch forward OR sideways since the long wall is the width, as you pointed out.
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post #1716 of 12050 Old 03-01-2013, 10:21 AM
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Originally Posted by AustinJerry View Post

Not necessarily.  Any of these models are approximations designed to help us address room response issues.  I have an open floor plan as well.

The first step in the process is to measure the listening area's frequency response, 15-20,000Hz.  Looking at the measurement, you should look at several of the worst peaks and/or dips, and note the frequency range in which they occur.  These peaks/dips are the result of interactions with rooom modes.  The question is, which room modes?

Next step is to pick a room lenght, width, and height to enter into the standing wave calculator (download a copy here).  For the room length, I would measure from the wall where the TV is to the bak wall where the stairs are.  For width, I would measure from the wall with the couch to the wall where the left surround is placed.  When you enter these values into the calculator, see if any of the calculated room modes match up with the peaks/dips in your frequency measurement.  If yes, then you can use this information to experiment with placements to see if you can get any improvement.

If none of the calculated standing waves align with the measurements, you can try entering the room width as the width of the entire open space, and see if any calculated standing waves match the measurements.

If you still can't get the calculations to match up with measurements, there are still general guidelines that you can follow for speaker and sitting locations.  Place speakers at 1/4 and 3/4 positions across the front wall, or at 1/6 and 5/6.  Place these speakers 1/8 of the length away from the front wall.  etc.

The point is, experiment with placement, and measure!

Thank you. An action plan is always nice to have!

For the most part I have what I consider to be pretty good sound already, but I'm always eager for more.

I was at home for lunch today, and we decided to watch something on the DVR. We put it on and there was a kid's show in Dolby Digital playing. That's when I heard the clanking sound, knew it was the mailbox outside the front door, and said to my wife "the mail's here"... Only it wasn't. It was a surround effect that was absolutely convincing. Convincing enough that I was fooled yet again after we were done watching "The Colbert Report" and "Peter Rabbit" was still on.

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post #1717 of 12050 Old 03-01-2013, 10:49 AM
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Originally Posted by AustinJerry View Post

If you examine a specific standing wave, then the standing wave is at its maximum SPL at the top of the arc, and at its minimum SPL at the bottom of the arc.  So, for example, look at the primary standing wave of the 18.5' wall, which is 31Hz.  If you sit in the center of your couch, then you will be sitting in a null WRT the 31Hz mode, i.e. you should not be able to hear a 31Hz tone.  However, at this same sitting position, you are at a peak of the standing waves for the 10.5' wall, so you would hear 54Hz, 108Hz, 163Hz, 217Hz, etc. emphasized at this position.  With the couch against the back wall, sitting in the center spot would not be very good.

There are two ways to use the standing wave model to produce smoother results.  First method is speaker placement.  If you place a speaker in a standing wave null, then you excite that null and reduce its effect.  So, for your two front speakers, placing them at the 1/4 and 3/4 dimensions of the 18.5' wall, i.e. at 4.5' and 13.5' would help the 61Hz mode.  And placing the same speakers 1.25' in front of the wall would help the 217Hz mode, placing them 1.75' in front of the wall would help the 163Hz mode, and placing them 2.5' in front of the wall would help the 108Hz mode.  You need to look at your overall frequency response measurements to decide if any of these placements address response issues, and then decide if you can live with moving the speakers.

For a single sub, the model suggests placing it in the middle of the front wall, which would help the 31Hz mode.

Placement to address modes associated with the ceiling height are more difficult.

The next thing you can do is to sit in a spot that minimizes room mode effects.  Sitting in the center of the couch is usually best for imaging, but be aware that you would be sitting in a 31Hz null.  Moving the couch away from the wall would likely improve sound significantly, with 1.25', 1.75', and 2.5 ft being the three distances to try.  I would simply measure these three distances first to see what improvement you might expect.

Does this make sense?

Thanks for explaining the meaning of the arc. (Swore I heard that in a movie). I mistakenly thought the bottom of the V-shape represented the standing wave at its maximum SPL.

I'm sure it will all start to sink in once I start on measurements this weekend.

Also installed Dropbox to share files.
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post #1718 of 12050 Old 03-01-2013, 11:19 AM
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Originally Posted by Pres2play View Post

Let me see if I can read the Axial Standing Wave chart correctly. I can move the seating forward 2.5 feet, OR 7.5 feet to reduce the peak? Is that what the chart is telling me?
When it comes to seating, I look for where there is the least amount of variation in frequency response. From your chart, that looks to be around the 1/3rd divisions of room length (3½ feet from the back wall). By comparison, the worst places to sit are the midpoints of room length and/or width, where there is maximum variation in frequency response (look at your chart, the loudest peaks and deepest nulls are at the midpoints).

Of course this is exactly where I sit in my room, smack dab in the middle of the room width (but 2/3rd of room length from the front wall). I'll resort to sub/speaker positioning, room treatments, EQ, anything to minimize those peaks and dips, but I'm not willing to compromise symmetry for that last little bit of frequency response improvement. Could I sit at one of the 1/3rd divisions of room width to get smoother frequency response? Sure. Will I? No. This comes down to personal likes and dislikes: an asymmetrical soundstage bothers me more than frequency response vatiations. YMMV.

From your previous posts, I know you're not going to pull your couch 3½ feet out from the back wall. So if you can't do one of the 1/3rd divisions of room length, the next best seating locations seem to be around the 1/5th divisions (2.1 feet from the back wall). A bit more frequency response variation than the 1/3rd points, but certainly better than a seating location that includes peaks and/or nulls.

For those noticing a pattern, the mode calculator charts seem to indicate that even divisions (1/2, 1/4, 1/6) of room dimensions are good locations for speakers and subs, while odd divisions (1/3, 1/5) are good for seating. Now, if only I didn't have an odd-shaped room, I too would be able to take full advantage of those charts. They're still helpful, but each time I look at one I keep wishing I had a rectangular room.
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post #1719 of 12050 Old 03-01-2013, 12:29 PM
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I certainly agree with you on symmetry, Sanjay.  I have gone to a great deal of trouble to make sure that I am sitting in the exact center of my room (side to side), and that my five primary speakers (LCR and surrounds) are all the same distance from the MLP.  Even my four subs are in two pairs at the same distance from the MLP.  In my experience, the improved soundstage that comes from symmetry more than offsets anything else.  The MLP is at the 1/5 spot, front to back.

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post #1720 of 12050 Old 03-01-2013, 12:36 PM
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In my experience, the improved soundstage that comes from symmetry more than offsets anything else.
Yup, but that's a personal choice that you and I make. It is interesting to find people that fall on the other side of that compromise: e.g., knew someone that had a pair of Lay-Z-boys at 1/3 and 2/3 of room width. That would drive me nuts.

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post #1721 of 12050 Old 03-01-2013, 01:02 PM
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Originally Posted by sdurani View Post

Quote:
Originally Posted by AustinJerry View Post

In my experience, the improved soundstage that comes from symmetry more than offsets anything else.
Yup, but that's a personal choice that you and I make. It is interesting to find people that fall on the other side of that compromise: e.g., knew someone that had a pair of Lay-Z-boys at 1/3 and 2/3 of room width. That would drive me nuts.

You can have a symmetrical arrangement that is off-centre though - by that I mean you can sit exactly between the speakers even though the midpoint between the speakers is not on the centre line of the room. Doesn’t this make for better overall SQ potential? I seem to recall reading that if each speaker is the identical distance from each sidewall, for example, this can excite room modes and/or reflections in an undesirable way?  Do I recollect this properly?

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post #1722 of 12050 Old 03-01-2013, 01:15 PM
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You can have a symmetrical arrangement that is off-centre though - by that I mean you can sit exactly between the speakers even though the midpoint between the speakers is not on the centre line of the room. Doesn’t this make for better overall SQ potential? I seem to recall reading that if each speaker is the identical distance from each sidewall, for example, this can excite room modes and/or reflections in an undesirable way?  Do I recollect this properly?

 

When I first set up my listening room back a few years, I had a setup like you describe.  When I embarked on my journey of trying to improve my overall audio experience, I found centering everything in the room was more desirable.  There is a lot of discussion about whether reflections are good or bad, but there seems to be agreement on one thing--having balanced reflections (same from left and right) is more desirable than unbalanced reflections.  A room that is not centered produces uneven reflections, which is not good.

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post #1723 of 12050 Old 03-01-2013, 01:37 PM
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You can have a symmetrical arrangement that is off-centre though - by that I mean you can sit exactly between the speakers even though the midpoint between the speakers is not on the centre line of the room. Doesn’t this make for better overall SQ potential? I seem to recall reading that if each speaker is the identical distance from each sidewall, for example, this can excite room modes and/or reflections in an undesirable way?  Do I recollect this properly?
You might be recalling home theatre architech Russ Herschelmann, who was very influential when it came to symmetrical set-ups that were off-centre in the room (for the very reasons you mention). I tried it back in the day and ended up not liking it. I tend to light up my side walls with high gain early reflections, so following Herschelmann's approach made for an asymmetrical soundstage. Might not bother some people but was annoying to me to have the soundstage stretch out wider on one side than the other.

Besides, if you look at the mode calculator graphs posted in this thread, seems that symmetrical placement of speakers and subs yields benefits. Moving the entire set-up so that it is asymmetrical to room boundries would lessen my ability to use placement as a method of minimizing modal problems, forcing me to rely more on treatments and EQ. So IF I want to use symmetrical placement to improve modal response, then I have to decide whether I want to sit centered in my set-up (more symmetrical) or off-centre (smoother response). I can't do both.

Easier for me to figure out multiple methods to fix frequency response problems that come from sitting in the middle of room width than it is to figure out how to fix an asymmetrical soundstage. The latter can be done, but would involve absorbing enough early reflections that I would no longer enjoy listening to music on that sort of set-up.

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post #1724 of 12050 Old 03-01-2013, 03:30 PM
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For uploading of data files for analysis, is there any prefernce for either send space or dropbox?.
i'm still testing and moving sub(s) around but want to make available what I managed to record so far!

And would that be the entire .mdat file as REW asks to save?

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post #1725 of 12050 Old 03-01-2013, 03:54 PM
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For uploading of data files for analysis, is there any prefernce for either send space or dropbox?.
i'm still testing and moving sub(s) around but want to make available what I managed to record so far!

And would that be the entire .mdat file as REW asks to save?

 

Either service is fine.  And yes, the entire MDAT file.  You should also post:

 

- Frequency response 15-20,000, smoothing 1/6, for left+right+subs.

- Frequency response, 15-300, no smoothing, for left+right+subs.

- Room layout, or at a minimim, your room dimensions

- Room pictures, if you have them

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thank you for your excellent work. and really instlling some simplicity to this fascinating journey. who knew?

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post #1727 of 12050 Old 03-01-2013, 09:32 PM
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Originally Posted by AustinJerry View Post

If you examine a specific standing wave, then the standing wave is at its maximum SPL at the top of the arc, and at its minimum SPL at the bottom of the arc.  So, for example, look at the primary standing wave of the 18.5' wall, which is 31Hz.  If you sit in the center of your couch, then you will be sitting in a null WRT the 31Hz mode, i.e. you should not be able to hear a 31Hz tone.  However, at this same sitting position, you are at a peak of the standing waves for the 10.5' wall, so you would hear 54Hz, 108Hz, 163Hz, 217Hz, etc. emphasized at this position.  With the couch against the back wall, sitting in the center spot would not be very good.

There are two ways to use the standing wave model to produce smoother results.  First method is speaker placement.  If you place a speaker in a standing wave null, then you excite that null and reduce its effect.  So, for your two front speakers, placing them at the 1/4 and 3/4 dimensions of the 18.5' wall, i.e. at 4.5' and 13.5' would help the 61Hz mode.  And placing the same speakers 1.25' in front of the wall would help the 217Hz mode, placing them 1.75' in front of the wall would help the 163Hz mode, and placing them 2.5' in front of the wall would help the 108Hz mode.  You need to look at your overall frequency response measurements to decide if any of these placements address response issues, and then decide if you can live with moving the speakers.

For a single sub, the model suggests placing it in the middle of the front wall, which would help the 31Hz mode.

Placement to address modes associated with the ceiling height are more difficult.

The next thing you can do is to sit in a spot that minimizes room mode effects.  Sitting in the center of the couch is usually best for imaging, but be aware that you would be sitting in a 31Hz null.  Moving the couch away from the wall would likely improve sound significantly, with 1.25', 1.75', and 2.5 ft being the three distances to try.  I would simply measure these three distances first to see what improvement you might expect.

Does this make sense?

Jerry, I took another look at the chart and I see your point now. For width, all the arcs are at maximum SPL when they meet at 10.5 feet (exactly where I have my couch), and the 108 Hz resonance may account for the peak in the graph at that range. Do I have it right?
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post #1728 of 12050 Old 03-02-2013, 02:59 AM
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Originally Posted by AustinJerry View Post

Quote:
Originally Posted by kbarnes701 View Post

You can have a symmetrical arrangement that is off-centre though - by that I mean you can sit exactly between the speakers even though the midpoint between the speakers is not on the centre line of the room. Doesn’t this make for better overall SQ potential? I seem to recall reading that if each speaker is the identical distance from each sidewall, for example, this can excite room modes and/or reflections in an undesirable way?  Do I recollect this properly?

 

When I first set up my listening room back a few years, I had a setup like you describe.  When I embarked on my journey of trying to improve my overall audio experience, I found centering everything in the room was more desirable.  There is a lot of discussion about whether reflections are good or bad, but there seems to be agreement on one thing--having balanced reflections (same from left and right) is more desirable than unbalanced reflections.  A room that is not centered produces uneven reflections, which is not good.

 

Good feedback, Jerry, as ever. Because I only use my room for HT, all reflections IMO are considered 'bad' and need to be struck down with great vengeance and furious anger. Any ambience I expect to hear is already in the 5.1 soundtrack and capably reproduced by my fine array of carefully positioned speakers. 

 

I'm not disagreeing with you BTW - just stating my own preference here, although I do sit fairly symmetrically in my room (as far as it allows) and would almost certainly always sit absolutely symmetrically, room etc permitting.

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post #1729 of 12050 Old 03-02-2013, 03:03 AM
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Quote:
Originally Posted by kbarnes701 View Post

You can have a symmetrical arrangement that is off-centre though - by that I mean you can sit exactly between the speakers even though the midpoint between the speakers is not on the centre line of the room. Doesn’t this make for better overall SQ potential? I seem to recall reading that if each speaker is the identical distance from each sidewall, for example, this can excite room modes and/or reflections in an undesirable way?  Do I recollect this properly?
You might be recalling home theatre architech Russ Herschelmann, who was very influential when it came to symmetrical set-ups that were off-centre in the room (for the very reasons you mention). I tried it back in the day and ended up not liking it. I tend to light up my side walls with high gain early reflections, so following Herschelmann's approach made for an asymmetrical soundstage. Might not bother some people but was annoying to me to have the soundstage stretch out wider on one side than the other.

Besides, if you look at the mode calculator graphs posted in this thread, seems that symmetrical placement of speakers and subs yields benefits. Moving the entire set-up so that it is asymmetrical to room boundries would lessen my ability to use placement as a method of minimizing modal problems, forcing me to rely more on treatments and EQ. So IF I want to use symmetrical placement to improve modal response, then I have to decide whether I want to sit centered in my set-up (more symmetrical) or off-centre (smoother response). I can't do both.

Easier for me to figure out multiple methods to fix frequency response problems that come from sitting in the middle of room width than it is to figure out how to fix an asymmetrical soundstage. The latter can be done, but would involve absorbing enough early reflections that I would no longer enjoy listening to music on that sort of set-up.

 

I am flattered, Sanjay, that you would think I had read about Russ Herschelmann, and indeed maybe I even have and forgotten, but the influence you mention may have been echoed in something or other I happened across long ago. Either way, thank you for adding a layer of credibility to my ramblings :)

 

I so wish I had more space here to experiment the way you have with placement.  One day maybe...

 

For my view on reflections, I just regaled Jerry with my thoughts...

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post #1730 of 12050 Old 03-02-2013, 03:38 AM
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When it comes to seating, I look for where there is the least amount of variation in frequency response. From your chart, that looks to be around the 1/3rd divisions of room length (3½ feet from the back wall). By comparison, the worst places to sit are the midpoints of room length and/or width, where there is maximum variation in frequency response (look at your chart, the loudest peaks and deepest nulls are at the midpoints).

Of course this is exactly where I sit in my room, smack dab in the middle of the room width (but 2/3rd of room length from the front wall). I'll resort to sub/speaker positioning, room treatments, EQ, anything to minimize those peaks and dips, but I'm not willing to compromise symmetry for that last little bit of frequency response improvement. Could I sit at one of the 1/3rd divisions of room width to get smoother frequency response? Sure. Will I? No. This comes down to personal likes and dislikes: an asymmetrical soundstage bothers me more than frequency response vatiations. YMMV.

From your previous posts, I know you're not going to pull your couch 3½ feet out from the back wall. So if you can't do one of the 1/3rd divisions of room length, the next best seating locations seem to be around the 1/5th divisions (2.1 feet from the back wall). A bit more frequency response variation than the 1/3rd points, but certainly better than a seating location that includes peaks and/or nulls.

For those noticing a pattern, the mode calculator charts seem to indicate that even divisions (1/2, 1/4, 1/6) of room dimensions are good locations for speakers and subs, while odd divisions (1/3, 1/5) arood for seating. Now, if only I didn't have an odd-shaped room, I too would be able to take full advantage of those charts. They're still helpful, but each time I look at one I keep wishing I had a rectangular room.

I'm beginning to see...it seems just moving the UMM-6 mic away from the wall several feet reduced the noise floor.

With mic at MLP


Mic 2.5 feet away from the wall


I really don't mind sitting at one end of the couch if that's the sweet spot, but it will take a HUGE improvement in SQ for me to justify moving the couch forward several feet, and I'm talking both center and off-axis improvement. HST, I truly just want to learn REW so I can learn to measure my room for myself, and also not have to rely solely on my ears. I really want to thank you guys for your input. I can't wait to start applying this stuff over the weekend.
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post #1731 of 12050 Old 03-02-2013, 06:06 AM
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Originally Posted by kbarnes701 View Post

 

Good feedback, Jerry, as ever. Because I only use my room for HT, all reflections IMO are considered 'bad' and need to be struck down with great vengeance and furious anger. Any ambience I expect to hear is already in the 5.1 soundtrack and capably reproduced by my fine array of carefully positioned speakers. 

 

I'm not disagreeing with you BTW - just stating my own preference here, although I do sit fairly symmetrically in my room (as far as it allows) and would almost certainly always sit absolutely symmetrically, room etc permitting.

 

I agree, my comments on reflections would likely only make a difference for serious music listening.  I know you have a separate setup for music.

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post #1732 of 12050 Old 03-02-2013, 12:43 PM
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Question about measuring the center channel in REW:
I'm using HDMI connection from the laptop to my Denon 4311 (V-AUX source, HDMI-7 port). If i pick channel 3 as input, which should be the center channel, how can I get center channel output without running PLII Cinema, when Audyssey is enabled. Stereo mode reproduces the sound in my right speaker. Am I missing something obvious to set to force no signal processing from the HDMI mono signal from REW (i.e. source specific bitstreaming)?

In direct mode it works correctly, but that's with Audyssey off, of course.

BTW, if anyone still cares, I picked up the OmniMic 5.1 test DVD. From a quick look, it does the usual tests (sine sweep, bass sweep, pseudo-noise, delay) for each of the 5.1 channels, but only for individual channels, including LFE. That actually makes the ability to pick and choose two channel inputs in REW more useful.

Stuart

 

Denon 4311 with XT32 and Audyssey Pro

Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

MiniDSP 10x10 HD

PSB Imagine T2, Center, and Surrounds (as of 5/2014); HSU ULS-15 subs (2)

 

The Audyssey FAQ Guide can be found here:

http://www.avsforum.com/...

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post #1733 of 12050 Old 03-02-2013, 12:48 PM
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Here is another interesting use of REW to analyze what Audyssey room calibration is doing:

 

The graphs represent three measurements of each of my three front speakers (Green=Preout, Red=Audyssey On, Blue=Audyssey off):

 

Left front:

 

 

Right front:

 

 

Center:

 

 

Here is how to interpret the results.  Take the center speaker as an example.  The in-room un-corrected response (i.e. Audyssey off) shows nice peaks at 60Hz and 150Hz.  The preout measurement (which shows the correction Audyssey is applying to the center channel signal) shows inverse peaks at the same two frequencies.  The post-Audyssey in-room response shows that the Audyssey correction has completely erased both peaks, resulting in a nice smooth response.

 

Pretty cool, no?  Are we liking REW now?

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post #1734 of 12050 Old 03-02-2013, 12:50 PM
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Originally Posted by sdrucker View Post

Question about measuring the center channel in REW:
I'm using HDMI connection from the laptop to my Denon 4311 (V-AUX source, HDMI-7 port). If i pick channel 3 as input, which should be the center channel, how can I get center channel output without running PLII Cinema, when Audyssey is enabled. Stereo mode reproduces the sound in my right speaker. Am I missing something obvious to set to force no signal processing from the HDMI mono signal from REW?

In direct mode it works correctly, but that's with Audyssey off.

 

Since my laptop only supports two channels, I'm not sure I know the answer, Stuart.  Are you sure channel 3 is the center and not the LFE?  I know Keith will have the answer.

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post #1735 of 12050 Old 03-02-2013, 12:57 PM
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Originally Posted by AustinJerry View Post

Since my laptop only supports two channels, I'm not sure I know the answer, Stuart.  Are you sure channel 3 is the center and not the LFE?  I know Keith will have the answer.

In direct mode, channel 3 is center, and channel 4 is indeed LFE, which I confirmed with test tones. Everything else maps to the 'standard' layout, at least through channels 5 and 6 (surround left and right in my 5.1 system).

Keith has an Onkyo, not a Denon, and IIRC he's using something called 'Pure Audio'.

Maybe some of us with Denons want to stck with PLII Cinema for the center after all.....

Stuart

 

Denon 4311 with XT32 and Audyssey Pro

Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

MiniDSP 10x10 HD

PSB Imagine T2, Center, and Surrounds (as of 5/2014); HSU ULS-15 subs (2)

 

The Audyssey FAQ Guide can be found here:

http://www.avsforum.com/...

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post #1736 of 12050 Old 03-02-2013, 01:02 PM
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Originally Posted by sdrucker View Post


In direct mode, channel 3 is center, and channel 4 is indeed LFE, which I confirmed with test tones. Everything else maps to the 'standard' layout, at least through channels 5 and 6 (surround left and right in my 5.1 system).

Keith has an Onkyo, not a Denon, and IIRC he's using something called 'Pure Audio'.

Maybe some of us with Denons want to stck with PLII Cinema for the center after all...

AFAIK, Pure Audio is the same as Direct Mode, or perhaps Pure Direct Mode.

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post #1737 of 12050 Old 03-02-2013, 01:07 PM
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Originally Posted by sdrucker View Post

Question about measuring the center channel in REW:
I'm using HDMI connection from the laptop to my Denon 4311 (V-AUX source, HDMI-7 port). If i pick channel 3 as input, which should be the center channel, how can I get center channel output without running PLII Cinema, when Audyssey is enabled. Stereo mode reproduces the sound in my right speaker. Am I missing something obvious to set to force no signal processing from the HDMI mono signal from REW (i.e. source specific bitstreaming)?

In direct mode it works correctly, but that's with Audyssey off, of course.

BTW, if anyone still cares, I picked up the OmniMic 5.1 test DVD. From a quick look, it does the usual tests (sine sweep, bass sweep, pseudo-noise, delay) for each of the 5.1 channels, but only for individual channels, including LFE. That actually makes the ability to pick and choose two channel inputs in REW more useful.

 

I just use basic Multichannel 5.1. When I select '3' in REW it plays the centre channel. No DSP applied. Dunno how you do it in Denon but with Onks you can just cycle through the DSPs until you get to M/Ch 5.1. 

 

BTW, I don't use Pure Audio normally - I may have mentioned I used it for a specific purpose, or maybe when I had no idea at all what I was doing with REW  ;)

 

Basically you select it in the AVR just as you would select any source that you don't want to use a DSP on - straight 5.1 Dolby etc, except it comes up as M/ch (or it does om the Onk anyway).

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post #1738 of 12050 Old 03-02-2013, 01:10 PM
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Originally Posted by AustinJerry View Post

Here is another interesting use of REW to analyze what Audyssey room calibration is doing:

The graphs represent three measurements of each of my three front speakers (Green=Preout, Red=Audyssey On, Blue=Audyssey off):

Left front:




Right front:




Center:




Here is how to interpret the results.  Take the center speaker as an example.  The in-room un-corrected response (i.e. Audyssey off) shows nice peaks at 60Hz and 150Hz.  The preout measurement (which shows the correction Audyssey is applying to the center channel signal) shows inverse peaks at the same two frequencies.  The post-Audyssey in-room response shows that the Audyssey correction has completely erased both peaks, resulting in a nice smooth response.

Pretty cool, no?  Are we liking REW now?

OK, this kills my remaining angst over moving from OmniMic...biggrin.gif

Probably the coolest example of what Audyssey, and REW, can accomplish ever, on one easy to follow graph. What does the sub look like with no or more limited smoothing than 1/6th (1/12 or 1/24th)?

Stuart

 

Denon 4311 with XT32 and Audyssey Pro

Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

MiniDSP 10x10 HD

PSB Imagine T2, Center, and Surrounds (as of 5/2014); HSU ULS-15 subs (2)

 

The Audyssey FAQ Guide can be found here:

http://www.avsforum.com/...

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post #1739 of 12050 Old 03-02-2013, 01:11 PM
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Quote:
Originally Posted by AustinJerry View Post

Here is another interesting use of REW to analyze what Audyssey room calibration is doing:

 

The graphs represent three measurements of each of my three front speakers (Green=Preout, Red=Audyssey On, Blue=Audyssey off):

 

Left front:

 

 

Right front:

 

 

Center:

 

 

Here is how to interpret the results.  Take the center speaker as an example.  The in-room un-corrected response (i.e. Audyssey off) shows nice peaks at 60Hz and 150Hz.  The preout measurement (which shows the correction Audyssey is applying to the center channel signal) shows inverse peaks at the same two frequencies.  The post-Audyssey in-room response shows that the Audyssey correction has completely erased both peaks, resulting in a nice smooth response.

 

Pretty cool, no?  Are we liking REW now?

 

Way cool, Jerry!

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post #1740 of 12050 Old 03-02-2013, 01:14 PM
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Originally Posted by sdrucker View Post

 
OK, this kills my remaining angst over moving from OmniMic...biggrin.gif
 

 

OmniMic is beautifully simple - but it's a Nissan compared to REW's Ferrari IMO. 

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