REW Jriver playback

[nzlowie]

Hi guys

 

I'd like to play a REW sweep from my JRiver player using the filters I've set and measure the result, I did some reading and found you could do an offline measurement trouble is I can't same the wav file as it says I should. Also can't see Import sweep recordings in the file menu.

 

So can I take measurements through JRiver? At the moment I use REW on my laptop independent of the PC that runs JRiver, also I don't want to doing anything like install REW on my music PC.

 

Idea's please.

[Satanica]

I plan to do something similar, I have a UMIK-1 microphone on its way from Hong Kong.

 

I plan to use the same computer for playback of REW sweep tones to the JRiver WDM driver sound device in Windows which will then route to JRiver which will then output to my sound interface device (USB) which will go to my amps and then to my speakers to be picked up by the UMIK-1 which will then send data to REW via USB, simple. 

[Keith_W]

This is the procedure you need. 

 

1. Create log sweep for offline playback

- In REW, go to "Generator". You will get this screen: 

 

 

- In the Generator, set start frequency 20Hz, End frequency 21kHz, 1M length, and max out the RMS volume at -3.0. Click on WAV. 

- The window on the left pops up. Choose your sweep channel (in this case Left), and make sure the "Add timing reference signal" and Sample rate of 48kHz is selected. 

- Click "OK" to save the .WAV file. I save it on my desktop and give it a name like "logsweep48-left.wav" or "logsweep48-stereo.wav"

 

2. Load the .WAV file into your player of choice

- Check that you set output to 48kHz and ASIO output correctly

- Verify that the .WAV sound is correct by playing it through your speakers. You should hear a high frequency chirp followed by a normal log sweep. 

 

3. In REW, set up for measurement: 

- Open REW and click on the "Measure" button: 

 

 

Choose "Use Acoustic Timing Reference" 

- Make sure "Wait for timing reference" is checked

- Set start freq, end freq, level, and length to be exactly the same as the .WAV file you recorded earlier. 

- Set inputs correctly

 

4. Begin measurement

- In REW, click on "Start Measuring". You will see the output meter jump and then settle to zero. 

- Go to your player software and press PLAY

- Immediately go back to REW and watch. You will see the Input bar jump (indicating the chirp) and REW immediately begins taking the measurement. 

- IF REW indicates clipping or insufficient volume, stop playback, adjust the output volume and repeat Step 5. 

- Enjoy your new measurement!

BTW ... if it is filters you want to measure, it is far better to take the measurement from your DAC output rather than to send it through the speakers and the microphone and subject it to all the vagaries of speaker and room induced distortion. Of course, if you want to see what the total corrected result (speaker + room correction) looks like, use the above procedure.

 

To be able to measure filters alone, you need to be able to loop back the DAC output signal to the digital input on your PC. I know how to do this. If you are interested, just ask. 

Edited April 27, 2018 by Keith_W

[nzlowie]

I don't want to screw with my dedicated Audio pc, just want to have the REW sweep as a wav file that plays through Jriver and gets measured on my REW equipped laptop. That way I'll see the true effect of the eq filters I set in REW so hope we can actually do it this way??????

[Keith_W]

Yeah you can certainly do that. Follow the procedure I posted and generate all the .WAV files you need on your laptop. Then transfer the .WAV file to your dedicated audio PC and continue from there. Use your laptop to take the measurement. Easy. 

[nzlowie]

Thanks @Keith_W 

I tried this last night from a guide I found online, think it may have been for a previous version but still the same concept. Went right through the options and clicked save, it brought up the location to save to so I named it whatever and saved, trouble is nothing actually got saved! No file created.

 

I'll step through your guide later on and see if there's anything I missed.

 

Yea it's the effect of the filters on speakers and room that I'm looking.

 

Thanks again for your guide.

[Keith_W]

nzlowie I guess you have to do the usual: 

 

- make sure you have the latest version of REW installed

- remember the file location. If in doubt, save it on your desktop. 

[Satanica]

1 hour ago, nzlowie said:

Yea it's the effect of the filters on speakers and room that I'm looking.

If you're using Windows, why not try using the JRiver WDM driver like I wrote earlier?

The WDM driver is basically a virtual sound device in Windows which I presume REW can output to as if it was a real sound device in Windows.

Edited April 28, 2018 by Satanica

[nzlowie]

Updated to the latest version of REW so I could do this offline sweep. Works good but for some reason the output level of the left sweep is a lot quieter than the right even though both settings were the same, no real drama, just turn the amp up doing the left measurements.

 

Now I can see the differences in the Jriver filters.

[JPete9]

connected your mic to the jriver windows machine and select the jriver whatever its called as the audio output device and run your sweep as normal.

 

I think there is a few other options in windows to host the filters system wide...its not very easy to do in software on mac.

 

Post a pic of the before and EQ response? I've been playing in REW a lot lately too. But I am tackling nulls not peaks so eq is not a lot of value, until i have bass nulls sorted. but it defintely fun to play with...you could try the dirac live trial and it will let you sommething similar, probably easier.

 

[nzlowie]

So had some success with this over the weekend. Recorded and saved (To my JRiver library) a sweep tone > 200hz, any bass eq will be done in the bass amp as it has eq function. Spent a bit of time setting filters to produce a flat response with the mic 750mm from the horns, didn’t want it further away as I could be influenced by the room. Once I had one channel pretty good I copied these filters across to the other channel (All in JRiver). Looking back at my old measurements I saw that both L&R horns behaved pretty much the same. Only had to make a couple of small changes between the left and right channel filters, they’re now within .5db of each other from just above the xover to 10k +.

 

Now that I have a flat response I’m just using the JRiver equaliser to introduce some room curve, just rolling off the HF a db or so. Work in progress but I’m happy with the result, its easy to turn off or on the filters from my listening spot to hear the difference. 

 

Should have thought about this ages ago!  (Will post before and after sweeps when I get back from work)

[Keith_W]

Glad to hear that it worked! 

[nzlowie]

Glad to hear that it worked! 

Thanks for your help.

[nzlowie]

So here are the before and after traces, separated for clarity. The large dip at around 12.5k is a calibration issue it think as its always been there no matter what speakers I test.....

 

The area that concerned me pre JRiver filters was the dip in level between 3.5-6khz. The filters have brought this back and made a big improvement to the final sound. Well worth doing!

 

Edited May 6, 2018 by nzlowie