0

Measurement problems with Airplay output in REW Room EQ Wizard

De Adi

August 22, 2018 20:47

None

Follow

ciao hifiberry

after downloading the dsptoolkit, i followed the doc about REW: 

https://github.com/hifiberry/hifiberry-dsp/blob/master/doc/rew-basics.md

configured DSP-profile is ~/dsp/beovox-cx100.xml

with stereo adjustment. 

In REW I select "AirPlay" as Output Device to measure the stereo CX100 and beocreate 4Ch amp and get weird results with 4 different mics. 

 

I did not hear any pops or clicks.

I tested the Airplay Output via Ableton Live with .wav files of Grey Noise and linear 20-20k sweep and I was able to monitor frequencies above 2kHz. But actually ears alone are prooving, that there is content

What am I doing wrong? 

(While writing this, I will try to monitor/mic-measure de REW sweep via Ableton tomorrow)

Btw, my soundcard is calibrated and I also did another test measurement on my Focal Shape Twin Speakers, which worked out.

Best wishes

Adi

 

• Facebook
• Twitter
• LinkedIn

4 comments

• 0
  
  transfers August 22, 2018 22:25

  Hi Adi

  This would be best addressed to REW support, but if you are using 4 different mics then it isn't surprising that you get non-correlated results. You should use one mic in 4 different positions.

• 0
  
  HiFiBerry team August 23, 2018 04:16

  Hi Adi,

  are you using Airplay to stream the data to the Beocreate? This might be the problem. As Airplay uses compression and timing corrections, the signal can be modified. This might not work with the measurements. I recommend a direct connection from your PC to the Beocreate via TOSLink.

  Best regards,
  Daniel

• 1
  
  De Adi August 23, 2018 08:54

  Hey Daniel

  Your answering rate is absolutely fantastic throughout this forum. Thanks indeed.

  Yes, I am using Airplay stream as Output Device in REW. 

  @transfers: I wanted to proove funcition of my measurement mic/setup

  And I am also able to measure/hear frequency above 2kHz when I stream filter sweep signals out of REW Airplay and monitor them in Ableton with Fabfilter EQ.

  Assuming I will open the CX100 to access Toslink Input for the signal chain and generate REW data for acoustic room optimizations with dsptoolkit, but then still always be listening through Airplay, does this make sense?

  Best whishes,

  Adi

   

   

   

• 0
  
  HiFiBerry team August 23, 2018 13:04

  Hi,

  measuring with TOSLink, but later listening via Airplay isn't a problem at all. Airplay should not have any impact on the frequency response itself. However, the delay and timing corrections introduced by Airplay might be an problem for the measurements with REW.

  Best regards,
  Daniel