Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 378 - AVS Forum
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post #11311 of 11326 Old Yesterday, 12:06 AM
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Originally Posted by markus767 View Post
Jerry, just a minor suggestion for improvement. When you talk about level calibration signals you should add RMS, e.g. -30dB FS RMS. The signal itself "wiggles" around that value.
Markus, is that necessary? The generator in step 8 shows "RMS Level dB FS," so when you dial up "-30" that covers it. Besides, there's no option for anything else.
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post #11312 of 11326 Old Yesterday, 12:14 AM
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I think it doesn't hurt to be as specific as possible.

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post #11313 of 11326 Old Yesterday, 07:17 AM
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Originally Posted by markus767 View Post
Hi Jim,

I switched off loopback and even tried to create severe mismatch of sample rates and bit depths but the resulting impulse responses never looked as dissimilar as what you and Jerry have shown. I'm running REW on a Mac.
Thanks for trying to recreate the problem.

Since Jerry and I both have the problem, there might be a lot of others as well, but they don't know it cause how many people did what I did to discover the inconsistency in the first place?

Perhaps after the holidays are over, John will chime back in either here or at HTS. In the meanwhile, I am going to use the 256k sweeps because they look the most like my Omnimic sweeps.

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post #11314 of 11326 Old Yesterday, 01:30 PM
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Originally Posted by jim19611961 View Post
Thanks for trying to recreate the problem.

Since Jerry and I both have the problem, there might be a lot of others as well, but they don't know it cause how many people did what I did to discover the inconsistency in the first place?

Perhaps after the holidays are over, John will chime back in either here or at HTS. In the meanwhile, I am going to use the 256k sweeps because they look the most like my Omnimic sweeps.
I've got a few other things to run through tonight, but if/when I get a chance, I'll give it a try. I'm not sure if Markus is using a USB mic, but if he's not, that might be difference. I have a CSL UMIK-1.
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post #11315 of 11326 Old Yesterday, 01:37 PM
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I have a couple of mics here but none of those USB mics.

Markus

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post #11316 of 11326 Old Yesterday, 01:41 PM
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Originally Posted by Bluescale View Post
I've got a few other things to run through tonight, but if/when I get a chance, I'll give it a try. I'm not sure if Markus is using a USB mic, but if he's not, that might be difference. I have a CSL UMIK-1.
I think that is the mic Jerry uses. A Dayton UMM-6 for me.

But that is what we need. More evidence.

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post #11317 of 11326 Old Yesterday, 07:11 PM
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Guys,

Wanted to ask about the audio output signal when using HDMI connected to the AVR.

Does REW send out PCM signal to the AVR?

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post #11318 of 11326 Old Yesterday, 07:12 PM
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Originally Posted by steveting99 View Post
Guys,

Wanted to ask about the audio output signal when using HDMI connected to the AVR.

Does REW send out PCM signal to the AVR?
On the front of my processor it says PCM.
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post #11319 of 11326 Old Yesterday, 07:31 PM
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Originally Posted by steveting99 View Post
Guys,

Wanted to ask about the audio output signal when using HDMI connected to the AVR.

Does REW send out PCM signal to the AVR?
Just curious, why do you ask? Does the type of signal make a difference?
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Originally Posted by Bluescale View Post
On the front of my processor it says PCM.
Thanks Bluescale!

Quote:
Originally Posted by AustinJerry View Post
Just curious, why do you ask? Does the type of signal make a difference?
I'm thinking of getting one of these: http://www.minidsp.com/ht-series/nanoavr-dl to test for Dirac in-a-box.

Would like to compare Dirac to Audyssey.

My thinking is to check the frequency and timing to see what Dirac has done. So want to use REW to take the before and after Dirac REQ. The NanoAVR-DL can only accept PCM signals so wanted to check that REW outputs PCM.

Bluescale has just confirmed this.

Already got the UMIK-1 mic for REW so don't need to purchase another one from MiniDSP. Got some unanswered questions to be resolved with MiniDSP. Will most likely place an order for the NanoAVR-DL once the questions are answered satisfactorily...

Reading through the preliminary manual now.

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post #11321 of 11326 Old Yesterday, 08:10 PM
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Yet another Noob here. I have dual Rythmik 15" subs, 16x13x7.5 theater with sound treatments. Installed REW and took a quick measurement. Here is what showed. Any thoughts on what it's showing? I'm trying to read up and learn what these things mean, just thought I'd reach out for some quick assessments.
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post #11322 of 11326 Old Yesterday, 08:13 PM
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Originally Posted by steveting99 View Post
I'm thinking of getting one of these: http://www.minidsp.com/ht-series/nanoavr-dl to test for Dirac in-a-box.

Would like to compare Dirac to Audyssey.

My thinking is to check the frequency and timing to see what Dirac has done. So want to use REW to take the before and after Dirac REQ. The NanoAVR-DL can only accept PCM signals so wanted to check that REW outputs PCM.
The nanaAVR HD also only accepts PCM (this is true for all miniDSP products, isn't it?) and it's definitely designed for use with REW:

http://www.minidsp.com/applications/...n-with-nanoavr

If you go through with this, I'll be really interested in your experience. That has the potential to be a great solution for a lot of people who want Dirac, but don't want to buy a new AVR.
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post #11323 of 11326 Old Yesterday, 08:17 PM
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Originally Posted by dsteak View Post
Yet another Noob here. I have dual Rythmik 15" subs, 16x13x7.5 theater with sound treatments. Installed REW and took a quick measurement. Here is what showed. Any thoughts on what it's showing? I'm trying to read up and learn what these things mean, just thought I'd reach out for some quick assessments.
Take a look at Jerry's guide here:

Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs

It has some information on posting graphs that make for us to see what's going on. Can you repost that with no smoothing and set to show all the way to 300hz? Again, take a look at the guide on specific information how to do that if you don't know.
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post #11324 of 11326 Old Yesterday, 08:52 PM
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Quote:
Originally Posted by dsteak View Post
Yet another Noob here. I have dual Rythmik 15" subs, 16x13x7.5 theater with sound treatments. Installed REW and took a quick measurement. Here is what showed. Any thoughts on what it's showing? I'm trying to read up and learn what these things mean, just thought I'd reach out for some quick assessments.
I see a frequency response curve that is reasonably well-shaped down to 10Hz, with a gently upwards-sloping "house curve". I see a dip at 60Hz that might be associated with the crossover frequency, or might be caused by a room mode. I see some unexplained little color bars at the bottom--don't know what they represent.

If you have the time, re-measure the frequency range 15-300Hz (or 10-300Hz if you are showing off). Include the legend at the bottom of the graph scree when you post. Tell us what you are measuring, i.e. is this subs only, or subs+mains? If the mains are included, what is the crossover point? Are you using room correction like Audyssey? Is the graph smoothed, or unsmoothed? If smoothed, post the new measurement unsmoothed.

So, not bad, but we don't have all the information yet. Answer ALL the questions, please.
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post #11325 of 11326 Old Yesterday, 10:00 PM
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Originally Posted by AustinJerry View Post
... I see some unexplained little color bars at the bottom--don't know what they represent...
Calculated room nodes if you input the dimensions in the right slots.

- modal analysis setup on the EQ window
- show modal frequencies option on the main window on some displays

I'll be back later...


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post #11326 of 11326 Old Today, 04:03 AM
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Originally Posted by jim19611961 View Post
I think that is the mic Jerry uses. A Dayton UMM-6 for me.

But that is what we need. More evidence.
Dayton EMM-6 mic via a usb preamp/audio device (RME Fireface 800), no loopback, IRs do not vary with length

sweep_length.png

I did notice that the input levels reported by the longer sweeps were lower than the shorter sweep. I wonder if this is related to your problem given the higher noise floor of the USB mic (and the fact that your sweeps look like they contain noise before the initial impulse)
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