Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 235 - AVS Forum
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post #7021 of 11294 Old 11-15-2013, 11:20 AM
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Quote:
Originally Posted by AustinJerry View Post

How about this:




biggrin.gif

Utterly amazing! And effortless...biggrin.gif

Stuart

 

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post #7022 of 11294 Old 11-15-2013, 11:20 AM
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Originally Posted by sdrucker View Post

But with a L/C/R+subs 'global' measurement in the modal region, how do we get this to work with REW/HDMI? Do a single input and use a weird DSP mode like Mono Movie, to have a single signal source for this purpose? Wouldn't Dolby PLII Cinema focus on the signal to the center channel?
You can either use PLII Music mode, which lets you adjust centre extraction (adjust Centre Width so that the test tone is equally loud in all three front speakers), or use the All Channel Stereo/Mono mode. In either case, disconnect or turn off your surrounds. You just want to measure your L/C/R and subs.

Sanjay
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post #7023 of 11294 Old 11-15-2013, 11:20 AM
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(1/3rd oct smoothing L & R)

Pretty. But is it useful?

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post #7024 of 11294 Old 11-15-2013, 11:21 AM
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Quote:
Originally Posted by AustinJerry View Post
 
Quote:
Originally Posted by kbarnes701 View Post
 

 

Better than mine. But this is what I was just saying - I can never get the mic dead centre if it is to be in the MLP, so I will therefore never be able to replicate that graph.

 

I wouldn't even worry about the 1/24th smoothing - we don't hear that way. And Nyal says he would use 1/3rd anyway, I bet your graph looks spectacular with 1.3rd smoothing!  Go on - let's see it... :)

 

How about this:

 

 

:D

 

It STILL looks better than mine!  LOL.

 

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post #7025 of 11294 Old 11-15-2013, 11:26 AM
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Quote:
Originally Posted by sdurani View Post

You can either use PLII Music mode, which lets you adjust centre extraction (adjust Centre Width so that the test tone is equally loud in all three front speakers), or use the All Channel Stereo/Mono mode. In either case, disconnect or turn off your surrounds. You just want to measure your L/C/R and subs.

Back to the future....I originally used PLII Music mode to look at L/C/R+subs in the OM days, exactly how you outlined. It's been awhile, but doesn't it have a bass boost at lower frequencies as you spread the signal around from two to three channels, relative to PLII Cinema or stereo? I think that back when we moved away from it for exactly that reason, but the documentation on the OM thread is sparse. Of course I could be wrong.

Some thoughts that Roger Dressler brought up about using PLII and PLIIz, and differences in Music and Movie modes, might be interesting in this context:
http://www.avsforum.com/t/1405366/bass-drastically-different-between-plii-music-vs-pliiz-height

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post #7026 of 11294 Old 11-15-2013, 11:28 AM
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Quote:
Originally Posted by AustinJerry View Post

How about this:




biggrin.gif

Looks like the left channel is 1 db louder than the right.

Time to start completely over Jerry rolleyes.gif

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post #7027 of 11294 Old 11-15-2013, 11:34 AM
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Quote:
Originally Posted by AustinJerry View Post

That's sounds optimistic, and Markus hasn't even weighed in today yet!  wink.gif

That's because all those topics have been discussed before and quite frankly I'm tired repeating myself over and over again.

Markus

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post #7028 of 11294 Old 11-15-2013, 12:00 PM
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Quote:
Originally Posted by sdrucker View Post

It's been awhile, but doesn't it have a bass boost at lower frequencies as you spread the signal around from two to three channels, relative to PLII Cinema or stereo?
Most 2-channel recordings have mono bass. PLII Cinema mode will sum anything mono to the centre speaker, which will sound different than that same bass coming from 2 speakers, which will sound different from PLII Music mode spreading the bass to 3 speakers. This is going to affect bass management as well.

If you listen to 2-channel music using your L/C/R speakers, then you should measure with PLII to see what the interaction is. If not, use the All Channel Stereo/Mono mode to distribute the signal. Or do both, just to compare belt and suspenders.

Sanjay
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post #7029 of 11294 Old 11-15-2013, 12:13 PM
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Greetings

I am looking to buy the UMIK 1 so I can start measuring. I noticed it comes with a mini tripod. Is this tripod tall enough to be placed on the sofa? Or is it better to get a mic boom stand? Also, if a mic boom stand is a better option, does the adapter ("on stage cm01") that is recommended in the audyssey thread also work for this UMIK microphone?

Thanks

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post #7030 of 11294 Old 11-15-2013, 12:14 PM
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Quote:
Originally Posted by kbarnes701 View Post
 

 

Thanks. Yes, I take into account the bass hump usually, looking at the FR range in 'two parts' IYKWIM

Really, Keith? I think I need another guide.

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post #7031 of 11294 Old 11-15-2013, 12:37 PM
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Quote:
Originally Posted by AustinJerry View Post
 
Quote:
Originally Posted by kbarnes701 View Post
 

 

Better than mine. But this is what I was just saying - I can never get the mic dead centre if it is to be in the MLP, so I will therefore never be able to replicate that graph.

 

I wouldn't even worry about the 1/24th smoothing - we don't hear that way. And Nyal says he would use 1/3rd anyway, I bet your graph looks spectacular with 1.3rd smoothing!  Go on - let's see it... :)

 

How about this:

 

 

:D

 

How do you plan to address what's going on from 250-15k Hz?!?! :p


EDIT:  Bitten again by the damn read ahead bug Barnes gave me!

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post #7032 of 11294 Old 11-15-2013, 01:21 PM
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Quote:
Originally Posted by kbarnes701 View Post
 

 

Hehehe. I will try listening from just one speaker. But I have to admit I have never noticed anything obviously 'wrong' when listening to mono through 2 speakers. I guess a 3.1 system would be more ideal.... with PLIIx to 'fix' things up.

Except now (for a change) you're opening up another can of worms. I posted this not long ago in my AVR's thread and, not surprisingly, have gotten no response, but it may be more relevant here:

 

I just upgraded my VSX-1020 to an SC-1222. As a long-time user of Room EQ Wizard (REW), I'm surprised I haven't seen any reference to it on this thread, especially after my recent measurements.

All the graphs below use 1/6 smoothing, Pioneer fronts and two subs.

This is the frequency response on "stereo":

 

 

 

But look what happens with PLll movie or game:

 

 

PLll music:

 

 

Neo 6: Cinema:

 

 

Neo 6: Music:

 

 

 

Which suggests that, FOR MY PARTICULAR SETUP, the processing that does the least damage to a stereo signal is Neo 6: Music.

Of more of a concern is just how much the other signal processing settings affect the frequency response, quite adversely.

Of course, YMMV, and I would be curious to see the results from other SC-1222 owners using REW (I know you're out there).

Michael


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post #7033 of 11294 Old 11-15-2013, 01:52 PM
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Originally Posted by JasonT35 View Post

Greetings

I am looking to buy the UMIK 1 so I can start measuring. I noticed it comes with a mini tripod. Is this tripod tall enough to be placed on the sofa? Or is it better to get a mic boom stand? Also, if a mic boom stand is a better option, does the adapter ("on stage cm01") that is recommended in the audyssey thread also work for this UMIK microphone?

Thanks

 

You absolutely need a mic stand. You don't need the cm01.

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post #7034 of 11294 Old 11-15-2013, 01:54 PM
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Quote:
Originally Posted by LastButNotLeast View Post
 
Quote:
Originally Posted by kbarnes701 View Post
 

 

Thanks. Yes, I take into account the bass hump usually, looking at the FR range in 'two parts' IYKWIM

Really, Keith? I think I need another guide.

BICBW.

I know what you mean.... ;)

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post #7035 of 11294 Old 11-15-2013, 01:58 PM
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^^ @Lastbutnotleast: I remember seeing the same thing when I first did PLII Music measurements of my L/R+subs with OM. However, with REW/HDMI, you would use a DSP mode only for < 300 Hz charts to understand the bass response for more than L/R+subs, particular L/R/C+subs all playing simultaneously. In that setup, what you're losing on the two channels playing conventional stereo is less relevant, because you're simply redistributing a two-channel signal to play on three channels, along with the subs. Again, this is only relevant, based on the last few days, to the modal region, as per Nyal.

As Sanjay noted:
Quote:
Originally Posted by sdurani View Post

You can either use PLII Music mode, which lets you adjust centre extraction (adjust Centre Width so that the test tone is equally loud in all three front speakers), or use the All Channel Stereo/Mono mode. In either case, disconnect or turn off your surrounds. You just want to measure your L/C/R and subs.

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)

 

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

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post #7036 of 11294 Old 11-15-2013, 04:10 PM
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Originally Posted by sdrucker View Post

^^ @Lastbutnotleast: I remember seeing the same thing when I first did PLII Music measurements of my L/R+subs with OM. However, with REW/HDMI, you would use a DSP mode only for < 300 Hz charts to understand the bass response for more than L/R+subs, particular L/R/C+subs all playing simultaneously. In that setup, what you're losing on the two channels playing conventional stereo is less relevant, because you're simply redistributing a two-channel signal to play on three channels, along with the subs. Again, this is only relevant, based on the last few days, to the modal region, as per Nyal.

As Sanjay noted:

 

I keep hearing references to PLII Music and REW measurements.  Remember, when measuring the center channel, use PLII Cinema, not PLII Music.  Why?  PLII Cinema alters the signal less and provides a closer to true measure of the center channel.

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post #7037 of 11294 Old 11-15-2013, 04:57 PM
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Quote:
Originally Posted by AustinJerry View Post

I keep hearing references to PLII Music and REW measurements.  Remember, when measuring the center channel, use PLII Cinema, not PLII Music.  Why?  PLII Cinema alters the signal less and provides a closer to true measure of the center channel.

That's what I used with OM ultimately for the center channel, but if you're trying to get L/C/R with subs...maybe that's why Sanjay suggested PLII Music.

Stuart

 

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Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

MiniDSP 10x10 HD

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post #7038 of 11294 Old 11-15-2013, 05:08 PM
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Quote:
Originally Posted by sdrucker View Post

That's what I used with OM ultimately for the center channel, but if you're trying to get L/C/R with subs...maybe that's why Sanjay suggested PLII Music.

I do not know of any way to get left, right and center all playing simultaneously using the mono REW test signal. Maybe you know something I don't?
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post #7039 of 11294 Old 11-15-2013, 05:13 PM
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Originally Posted by AustinJerry View Post

I do not know of any way to get left, right and center all playing simultaneously using the mono REW test signal.
Send it as a dual-mono (2-channel) signal.

Sanjay
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post #7040 of 11294 Old 11-15-2013, 05:15 PM
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Send it as a dual-mono (2-channel) signal.

Sorry, I don't know what you are talking about. Can you expand a bit?
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post #7041 of 11294 Old 11-15-2013, 05:46 PM
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Probably using a Y-adapter to send the same signal left and right.

Still, see my graph for PLII movie/game (probably Pioneer's equivalent of "cinema").

I have an advanced surround mode "extended stereo" that may work, but I didn't bother going through all of those modes. Oh well, another project for another time.


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post #7042 of 11294 Old 11-15-2013, 05:54 PM
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Originally Posted by AustinJerry View Post

Can you expand a bit?
Send the REW signal to the L/R channels of your receiver.

Normally this would be played back through your L/R speakers.

If you use PLII Cinema mode, ALL dual-mono content will be extracted to the centre output and be played back through your centre speaker.

If you use PLII Music mode, you can adjust the Centre Width parameter to extract just enough to the centre output that all three front speakers measure the same level.

The other (probably better) option I mentioned is using the All Channel mode to distribute the mono REW signal to all speakers simultaneously. Disconnect or turn off the speakerss you don't want to measure.

Sanjay
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post #7043 of 11294 Old 11-15-2013, 06:47 PM
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Quote:
Originally Posted by AustinJerry View Post

PLII Cinema alters the signal less and provides a closer to true measure of the center channel.
PLII Movie and Music treat the center signal equally. The only difference is the ability to apportion the center signal across L/C/R in the Music mode. If the Center Width control is set to minimum, C has the same signal as in Movie mode.
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post #7044 of 11294 Old 11-15-2013, 06:53 PM
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Quote:
Originally Posted by LastButNotLeast View Post

Except now (for a change) you're opening up another can of worms. I posted this not long ago in my AVR's thread and, not surprisingly, have gotten no response, but it may be more relevant here:

Which suggests that, FOR MY PARTICULAR SETUP, the processing that does the least damage to a stereo signal is Neo 6: Music. Of more of a concern is just how much the other signal processing settings affect the frequency response, quite adversely.
You are misinterpreting the curves. What they show is that the center speaker has a different response than the L/R. This is not caused by PLII.
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post #7045 of 11294 Old 11-16-2013, 03:01 AM
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Then why is it different for Neo?

:confused:


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post #7046 of 11294 Old 11-16-2013, 04:19 AM - Thread Starter
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Hi guys,

First of all, I must apologize to several of you who have PM'd me over the last week or two.

Unfortunately, family and life have intervened and this is the first time I've been able to post on AVS or anywhere else, in any forum or even read PM's in quite some time due to some personal issues. I do sincerely apologize for my lack of availability.

Rest assured I will be responding to PM's and getting caught up in replying to posts in this thread as well very soon.

I have managed to read every post in this thread from where I last left off, so at least I know which topics/posts I need to cover and will be working on them this weekend.

It is obvious folks are confused as to what they should be measuring, how they should be displaying it, and why, so I'm going to clear all that up right now.

  • Measure Left, Right, Center, and any/all other channels separately. The reason you want to do this is to see exactly how your speakers, individually, interact with the room so you can ensure the best placement for each speaker and choose the best listening position. If posting these measurements, full range measurements should be at 1/24th and at 1/6th octave smoothing. 1/24th is for working on a problem and when asking for assistance about resolving an issue or to properly show the issue and 1/6th is for showing the overall response.
  • Subs should first be measured separately from the L/C/R/etc speakers, but as a group. When showing FR of this range (below 300hz) always show unsmoothed. There is simply no reason to smooth this range and it is much more important to get this range flat because of the way our ear hears these frequencies. Look at the standard logarithmic display in REW. See how many frequencies are shown together in the higher end of the spectrum in such a short amount of space, IE: 2khz to 3khz in a 1/2 inch of space, yet the lower you go, the more resolution you see. Look at how much space it takes to view from 20hz down to 10hz for instance. Our ear hears the same way these frequencies are presented visually, so in the modal region we should not smooth. For instance, if a 40hz bass note is played and is 5db louder (than your reference "flat") then a 50hz bass note is played and is 3db quieter than 40hz, that is an 8db swing in only 10hz and at these frequencies is absolutely audible. If the same thing were to happen at 8000hz and 8010hz, you wouldn't notice the difference at all, which is why it's ok to smooth a little there. The reason we want to see the subs separately from the mains "first" is to ensure we have found the best placement for our sub or group of subs relative to our listening position(s) and only by measuring them separately from our (assuming bass managed/small w/ crossover) mains first can we find the best placement for them (to obtain the smoothest response) without possible interactions from the mains which could create or even hide problems with phase/interaction. Basically, by doing this measurement first, we'll later know how our speakers interact with our subs and whether it's positive or negative and where to look to solve the problems.
  • Once you've found the best locations (for speakers, subs, and listening position) you can then measure each channel PLUS the sub(s). When measuring L+subs, R+subs, etc, you should again show an unsmoothed response for below 300hz and above 300hz you can show 1/24th or 1/6th depending on the advice you're wanting or what you're trying to show. Never smooth more than 1/6th as it just hides way too much resolution. If when you measure L+Subs (or any other speaker plus subs) your response in the crossover range deteriorates from your sub(s) only measurements you then know you have poor phase interaction and you need to either raise the crossover, change the distance/phase settings on the sub(s) and/or your AVR, and possibly a combination of both. Without separate measurements first of your individual speakers and sub or sub "group" you won't know if including your speakers have made this response better or worse.
  • Once you're satisfied with your per channel + sub(s) response you can then combine L+R+Sub(s) and show the combined response BELOW 300hz unsmoothed. This is the ONLY measurement you "need" to show with the L+R combined with the sub(s). The reason for this is that most bass is summed/mono and you want to make sure your "combined" response is smoothest since this is what you'll actually be listening to most of the time as far as bass goes. This is the measurement I use when deciding what EQ to apply to my subs, as well. (I then take separate measurements with L+Subs and R+Subs AFTER EQ to verify that neither of the individual measurements are much different from each other)
  • If you decide to view a full range measurement with L+R+Sub(s) you will most likely be disappointed above about 1khz or so (most of the time and unless you are VERY careful and have very exact speaker and mic placement between the speakers) as the wavelengths start to become so small the slightest movement of the mic will cause phase interactions, comb filtering, and a very poor and inaccurate measurement in the higher frequencies. There really isn't any reason for this. Again, the only measurement necessary for L+R+Sub(s) - combined - should be to look at the overall bass response, below 300hz, unsmoothed.

As far as what you upload/show to the forum, that depends on what it is you're trying to share or need help with. Use your best judgment based on the information above and the problem or question at hand.

Also note that you should always overlay your L+Sub(s) and R+Sub(s) (plus any other speakers you measure and I recommend measuring the Center channel at a minimum in addition to L/R unless you're only designing your space for critical 2 channel music listening) and compare at both 1/24th and 1/6th smoothing. They should follow a similar path at 1/24th smoothing and at 1/6th smoothing should be within 2db of each other. (This is an arbitrary number I'm selecting based on what I've been able to pretty easily accomplish with proper placement and a reasonable amount of treatment in my past experience) . Truthfully, they need to be as close together as possible. I would trade a perfectly flat FR in one channel for a pretty close FR for each channel if it meant they matched up much more closely in a heartbeat.

By insuring both (or all) channels match as closely as possible you will enjoy smooth pans and proper imaging by getting the timbre (pronounced tamber) matched between all speakers.

So to sum up, measure subs as one group/one measurement no matter how many subs you have, measure each speaker individually, then each speaker combined with the subs, and only L+R+Subs to look at below 300hz and share your images at 1/24th or 1/6th depending on what it is you're trying to accomplish.

I "view" my full range graphs totally unsmoothed as well to try to combat comb filtering as much as possible. Any amount of smoothing will make this go away and by viewing unsmoothed I've been able to get +/- 5db with absolutely no comb filtering until 1khz or so.

My current response is +/- 2.5db at 1/3rd full range for each speaker + subs (taking into account my house curve which I've designed on purpose, of course), +/- 3db at 1/6th, and +/- 5db at 1/24th. I don't believe I could've gotten this (and my room isn't completely finished yet so I'm hoping for even better) if I didn't study the data using the methods outlined above.

I hope this clears things up.

There are many different ways of doing things and different reasons for doing things different ways. I'm not saying my methods, as outlined above, are the only "correct" way of doing things, but they sure are what I'd like to see in this thread for the reasons I've outlined in this post.

I realize people are confused and some even wonder if what they've done to this point is moot and whether they must start over. Absolutely NOT! I assure you if I saw totally misleading or inaccurate data before, (on a regular basis that is, not saying I haven't missed a one off here and there) I would've said something way before now.

Anyway, I have a lot more to say (I bet you find that hard to believe, huh Jerry et al biggrin.gif ) but this will have to do for now.

I promise I'll do my best to get caught up with everyone this weekend.

Thanks,

--J

Thanks to EVERYONE that Helps Make These Threads so Awesome!

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post #7047 of 11294 Old 11-16-2013, 04:20 AM
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@LBNL: I think because Neo doesn't route the signal from L and R through your C channel. What Roger is trying to say is that the responses you're trying to compare are of different channels (L and R vs C).
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post #7048 of 11294 Old 11-16-2013, 04:57 AM
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Jerry - I found that long post of J's to be very clear and very helpful. Perhaps incorporating the 'meat' of it into your Guide would be a good idea, and also save you a bit of work at the same time?

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post #7049 of 11294 Old 11-16-2013, 06:30 AM
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Quote:
Originally Posted by kbarnes701 View Post

Jerry - I found that long post of J's to be very clear and very helpful. Perhaps incorporating the 'meat' of it into your Guide would be a good idea, and also save you a bit of work at the same time?

Yes, of course. I am grateful that J summarized the recommendations--his guidelines will be trusted more than anything I could have put together. IMO, a simple link in the guide to J's post will probably be better than my attempt to summarize his recommendations.
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post #7050 of 11294 Old 11-16-2013, 06:47 AM
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As many of you recall, I conducted a review of the GIK Scopus tuned bass trap recently. After testing, I determined that the traps were not significantly reducing bass ringing at the targeted 40Hz frequency range, and decided to return them. I am pleased to report that GIK accepted the return and credited my account with not only the cost of the traps, but the shipping charges as well. In addition, I received a personal call from Glenn Kuras, President of GIK Acoustics, during which he and I reviewed the REW measurement file and discussed the results of the Scopus evaluation.

I mention this because it is rare to receive such excellent and personalized support from a vendor. I certainly makes me want to continue doing business with them.
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