# Using REW in an actice setup with multichannel USB soundcard and USB mic



## kandroid (Feb 9, 2015)

I am absolutely virgin to REW.
I just purchased the Dayton UMM-6 mic and am slowly learning to use it.

I need some basic help. If this question has already been asked and answered, moderators may delete this thread and direct me to the relevant thread or posts. I did some search but could not find what exactly I was looking for.

My current setup that I am trying to correct for room correction.

I am running a 4-way active stereo setup.

Hardware: 
ASUS Xonar U7 USB soundcard connected to my Dell Inspiron 6400 laptop running win 7 64bit OS.
Source Player: JRiver Media Center 20.
Mixer: WASAPI for windows, can also use ASIO driver provided by ASUS.
Xonar soundcard set to 7.1 output.
JRiver set to 7.1 output in its DSP setting.
Amplifier: 6-channel power amplifier and a Celestra mono amplifer to power the subwoofer
Speakers : DIY 3-way floorstanders using Peerless 10 inch midbass, 3.5 inch Morel midrange and Philips silk dome tweeters, Subwoofer: 12 inch Morel Ultimo in custom designed snclosure
Active Setup Design: All the crossover settings are in JRiver. JRiver outputs to soundcard the following way. Soundcard is connected to the multichannel power amplifier with RCA cables. the 3 pairs of the amps stereo outputs are connected to the individual pair of speakers (left/right midbass, midrange and tweeters). The center/sub channel of the soundcard is connected to the mono amplifier which then powers the subwoofer.
Channel 1/2 of soundcard powering midbass bandpassed at 80hz/500hz (12db slope)
Channel 3/4 of soundcard powering midrange bandpassed at 700hz/5000hz (12 db slope)
Channel 5/6 connected to subwoofer amp LPF at 63hz/18 db slope
Channel 7/8 of soundcard powering tweeters HPF at 5000hz/12db slope 

_Screenshot of the XO settings in JRiver_










In the above active setup, using the Dayton Audio UMM-6 mic how should I setup the input/output devices. 
Would I need a external SPL meter and do I need to calibrate the soundcard.
Should the output device be set to JRiver (as the DSP is functioning here) or to Xonar U7 (speakers). Since there is no support for WASAPI in REW, should I compulsorily use ASIO only.

Since Cross Spectrum Labs do not ship to my location, I had to buy from Dayton directly. So the caliberation file is not the 90 degree one but the 0 degree default provided by Dayton. Will this impact the accuracy of measurement. If so what is the solution? Do I need to calibrate the mic aswell?

I am absolutely new to room measurements etc and your help and advice can ease the burden.
Once I succeed with room corrections I intend to correct my car stereo aswell which too is running 4-way active.

Thanks


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## fusseli (May 1, 2007)

You can use the cal file from Dayton for your mic unless you want to ship it off to be calibrated again by Cross Spectrum Labs. You don't need an SPL meter since its a calibrated mic, you just need the cal file.

It sounds like you need your output to be Jriver since that's where all your processing is, then do you use an analog output from the Sonar to your speakers? Yes you need to calibrate the soundcard, but that's only possible if you can create a loop back.


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## AudiocRaver (Jun 6, 2012)

Assume part of what you want is to set levels and timing of the individual drivers. You will need a timing loopback cable. Temporarily dedicate one of the subwoofer outputs as your timing loopback output and figure out (good luck) what kind of cable you need to run from that output to the Xonar mic input, which will be selected as the timing input.

You will not actually calibrate the sound card because with the USB mic you will only be using its outputs in the measurements, not its input, so no point. Use the supplied calibration file and always point the mic directly at the speaker under test.

You will need to select jRiver as the output device and the USB mic as the main input device and the Xonar mic input as the timing input (again, good luck getting that to work, don't know if it is a mono or stereo mic input). Not sure if you will need ASIO for all this or not. Probably.

Once it is all working, the timing setup is quite involved, but we can supply links to threads that describe the process in detail.

BTW, you show 500 and 700 Hz mid crossover frequencies, is one a typo?


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## kandroid (Feb 9, 2015)

AudiocRaver said:


> Assume part of what you want is to set levels and timing of the individual drivers. You will need a timing loopback cable. Temporarily dedicate one of the subwoofer outputs as your timing loopback output and figure out (good luck) what kind of cable you need to run from that output to the Xonar mic input, which will be selected as the timing input.
> 
> You will not actually calibrate the sound card because with the USB mic you will only be using its outputs in the measurements, not its input, so no point. Use the supplied calibration file and always point the mic directly at the speaker under test.
> 
> ...


Thank you sir. It is a mono mic in the Xonar. 

But I don't get this concept about timing mic. What exactly is that and what role does it have to play in REW?

I was under the impression that Dayton USB is all I need to use and the Xonar as output medium.
I do want to measure the frequency/impulse response of all the individual drivers, however I have to do it through JRiver only, else my tweeters and midrange could blow (as I am not using passive crossovers) if I let it play the full bandwidth signal.

Do please link me to the relevant posts/threads

By the way I am also soon getting the UMIK-1 mic aswell. Should I wait and use that if it has any significant advantage over Dayton while using REW. 

Thanks


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## AudiocRaver (Jun 6, 2012)

Your application is quite advanced for a newcomer, but if you are patient I think we can help get you there.

First let me be sure I understand one thing correctly. Is part of what you intend to accomplish the time alignment of all your drivers? That one question makes a big difference.


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## kandroid (Feb 9, 2015)

AudiocRaver said:


> Your application is quite advanced for a newcomer, but if you are patient I think we can help get you there.
> 
> First let me be sure I understand one thing correctly. Is part of what you intend to accomplish the time alignment of all your drivers? That one question makes a big difference.


No sir, I am not time aligning the drivers. The imaging, depth etc is already quite exceptional. I managed it pretty will with speaker placement. My system is not in a audio friendly location in my home due to paucity of space. So I essentially want to do correction for wall reflections etc and also tune my subwoofer.


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## AudiocRaver (Jun 6, 2012)

Excellent. That definitely simplifies things.

The "timing loopback" mentioned previously can be ignored. Also, no need to calibrate your soundcard, it is meaningless unless it is being used for both mic input and audio output, you are only using its outputs and they are usually flatter than the mic input anyway, so that simplifies things also.

Use the supplied calibration file and point the mic directly at the speaker under test.

REW's output should be to jRiver. That way jRiver can do all the crossover and distance things it needs to. ASIO is your best bet getting it all to talk to each other. WASAPI and ASIO are very similar in how they handle the audio, so leaving it set for ASIO is a good choice. The free ASIO4ALL driver is probably the most universal and versatile available.

Then jRiver will be set to output to your sound card.

Others have done this with great success, it should be fairly straightforward to set up.

Do not know if UMM-6 has sensitivity setting in the calibration file or not. Anyone? Look at the cal file with a text editor. If the first line reads

"Sens Factor =-16.582dB, SERNO: 7000033"

(including quotes) or something like that, then sensitivity is automatically set. If not, you will need an SPL meter or some kind of reference. If you don't have one and if someone can supply us with a "typical" UMM-6 sensitivity number, you could edit it into the cal file and not be too far off for the kind of work you are doing.

No advantage in waiting for the UMM-1, either will do what you need with the appropriate cal file with sensitivity info entered.

Doing frequency response correction - assume you will be using filters built into jRiver with filter values generated by REW, correct?

When you get to looking at reflections, a little special care will be in order - we will address that when we get to it.


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## kandroid (Feb 9, 2015)

Thank you for the heads-up. I will start the first measurements tonight and post the results.
The cal file has sensitivity settings so that is not an issue.


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## kandroid (Feb 9, 2015)

AudiocRaver said:


> Doing frequency response correction - assume you will be using filters built into jRiver with filter values generated by REW, correct?
> 
> When you get to looking at reflections, a little special care will be in order - we will address that when we get to it.


Should I measure midbass/ midrange and tweeters individually within the crossover band or by playing them full range without any slope or crossover?
Also should I do both near field and listening position measurements
I do not have t/s parameters for the midbass.


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## AudiocRaver (Jun 6, 2012)

Measure with xovers active, it would be good to see individual driver sweeps and a full range sweep, but only one side at a time (left or right).

Close to the speaker will tell us about it, at LP will tell us more about the room. Make sure distance from each speaker to the LP measurement point is matched very closely, 1/4 in is just close enough. Then you will have fairly accurate RELATIVE timing numbers to look at when looking at reflections & such.


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## kandroid (Feb 9, 2015)

AudiocRaver said:


> Measure with xovers active, it would be good to see individual driver sweeps and a full range sweep, but only one side at a time (left or right).
> 
> Close to the speaker will tell us about it, at LP will tell us more about the room. Make sure distance from each speaker to the LP measurement point is matched very closely, 1/4 in is just close enough. Then you will have fairly accurate RELATIVE timing numbers to look at when looking at reflections & such.


ok will follow your advice. I am just a little apprehensive about the midbass, hunting for a good 10 incher to replace the current one.


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## natehansen66 (Feb 20, 2011)

I don't think setting the output on REW to ASIO is going to work how you would like with MC, but it's been awhile since I've tried it. Are you using MC's WDM driver or something else? If you're using the WDM then you'll set the REW output to the JRiver driver, and the Windows default device should also be set to JRiver's driver.

I use REW set to Java when taking measurements with the audio routed through JRiver. I've been running active with MC for about 3 years now.

You can get the time alignment reasonably close with LR type filters.....I'm talking about the final acoustical slope here. Just flip one of the drivers out of phase and use delay (within reason of course) until you get the deepest null. Flip the polarity back and you should have good summation through the xo if you have the correct response for each driver.


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## AudiocRaver (Jun 6, 2012)

natehansen66 said:


> I don't think setting the output on REW to ASIO is going to work how you would like with MC, but it's been awhile since I've tried it. Are you using MC's WDM driver or something else? If you're using the WDM then you'll set the REW output to the JRiver driver, and the Windows default device should also be set to JRiver's driver.
> 
> I use REW set to Java when taking measurements with the audio routed through JRiver. I've been running active with MC for about 3 years now.
> 
> You can get the time alignment reasonably close with LR type filters.....I'm talking about the final acoustical slope here. Just flip one of the drivers out of phase and use delay (within reason of course) until you get the deepest null. Flip the polarity back and you should have good summation through the xo if you have the correct response for each driver.


I defer to natehansen66's experience level for setting up REW with MC. Probably best to try it his way first.

If you do get into driver time alignment, check out jtalden's detailed instructions here.


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## 3ll3d00d (Jun 6, 2006)

REW to jriver via asio line in can work and you can also do loopback without a physical cable if you have a mixer app that can do loopback. The best way to set it up so it works reliably seems quite hardware specific though so try all ways to see what works best.


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