UPnP support

[Krunok]

Hello,

I'm currently helping with a project to port BruteFIR convolver to Volumio running on Raspberry PI. The idea is to add room eq support to Volumio platform. I was extensively using REW to design filters in the scenario when DAC was connected to USB port via ASIO but that is not possible anymore with Volumio as it is UPnP/DLNA renderer and as such is not recognised by Windows client as audio device.

Some music players (Foobar, MusicBee) have added simple support for UPnP/DLNA client so a file can be played via Volumio. Do you think a support for UPnP/DLNA can be added to REW so measurements can be done with REW in the UPnP/DLNA setup?

Br
krunok

 

[John Mulcahy]

Easiest would probably be to save the measurement sweep to a file including the timing reference and to make measurements by using the "Wait for timing reference" option on the Measure dialog, starting the measurement then playing back the file.

 

[Krunok]

Easiest would probably be to save the measurement sweep to a file including the timing reference and to make measurements by using the "Wait for timing reference" option on the Measure dialog, starting the measurement then playing back the file.

Thank you for the quick reply!
Can you please explain how do I save the measurement sweep to a file, including the timing reference?

 

[John Mulcahy]

It can be saved from the generator, pretty much the first part of the offline measurement process.

 

[Krunok]

In the version I'm using (V5,19) there is no "Add timing reference signal" option.

I updated to V5.20 beta 1 but still no luck:

Once I have sweep signal file how exactly do I record sweep response? Do I go to "Measure", check "Wait for timing reference" box, press Start measuring and play sweep signal file?
I would expect REW to wait for the timing reference to be played to start recording but that is not what is happening.

 

[John Mulcahy]

To save the measurement sweep you need to select Meas. Sweep as the signal type, you currently have Sine Wave selected.

With "Wait for timing reference" selected REW will not start capture until it sees the timing reference. The sweep will still be played out.

 

[Krunok]

To save the measurement sweep you need to select Meas. Sweep as the signal type, you currently have Sine Wave selected.

With "Wait for timing reference" selected REW will not start capture until it sees the timing reference. The sweep will still be played out.

Ah, ok, my bad - thank you!

I have created a sweep for left, right and both channels. How do I import the "both" variant when there is no "both" button?

 

[John Mulcahy]

Import is for recordings. You should not be doing that. Just use the normal REW measure process with "Wait for timing reference" selected and aftre starting the REW measurement play back the sweep file you saved through Volumio.

 

[Krunok]

Import is for recordings. You should not be doing that. Just use the normal REW measure process with "Wait for timing reference" selected and aftre starting the REW measurement play back the sweep file you saved through Volumio.

Ok. So, I did as you told me and it went as it should, but the measurement graph looks weird after 300Hz. I'm sure my speakers don't have such characteristics so I'm probably doing something wrong.

This is how measurement sweep file looks in Audacity:

 

[John Mulcahy]

The sweep file looks fine, but the measurement doesn't - it is unlikely that your speaker is 74m away

What are your REW soundcard settings? If the REW output device is the same as the device the mic is connected to crosstalk from output to input may be allowing REW to pick up the timing reference from the locally generated sweep. You should see the Measure dialog sat showing 'Waiting for timing reference' until you play back the file. If that isn't happening and the same soundcard is being used for output and input, try muting the output or setting output volume to zero.

 

[Krunok]

LOL No, they are app 4m away.

Here are my soundcard settings:

As you see I tried to set sweep level to -60dB but no luck.

I'm using analog mic Dayton Audio iMM-6 plugged into the port of my notebook.

https://www.soundimports.eu/en/imm-6.html

Yes, REW waits for the timing reference signal and correctly starts recording after it hears it.

 

[John Mulcahy]

On the soundcard settings tick the box labelled "Control output mixer/volume" and set volume to zero there. If REW does sit showing "Waiting for timing reference" until you play the file that probably isn't the issue though. Do you get normal measurements if you connect the laptop directly to the system rather than going through Volumio? Does your notebook have a TRRS headset port?

 

[Krunok]

On the soundcard settings tick the box labelled "Control output mixer/volume" and set volume to zero there. If REW does sit showing "Waiting for timing reference" until you play the file that probably isn't the issue though. Do you get normal measurements if you connect the laptop directly to the system rather than going through Volumio? Does your notebook have a TRRS headset port?

Yes, I get normal measurement when laptop is connected to the DAC via USB cable:

I also get normal measurement with HOLMS over Airplay with Volumio:

However, as Airplay functionality stopped working on Volumio and as I anyhow use REW for filter generation and export to rePhase, using REW for measurements would be a perfect solution for me.

Yes, my notebook has TRRS headset port which corresponds to the male TRRS jack my mic has.

 

[Krunok]

I made 2 measurements of the portable BT speaker connected to my notebook, thus throwing Volumio and UpnP out of the equation.

First measurement was "classic", without timing reference. Meaasurement was made nearfield, app 20cm from the speaker and little gismo performed pretty well:

Second emasurement was made with timing reference. I first started measurement, REW waited until I started play of the measurement sweep WAV file with MusicBee and recording started after the timing reference signal was played, as it should. These were the preferences:

Measurement window:

And the measurement graph:

Please help, I don't know where to go from here..

P.S. as you can see the version was V5.20 Beta1. I have also tried V5.19 Beta 8 with the same results. I'm runnig 64 bit Windows 10 on my notebook with all latest updates.

 

[John Mulcahy]

All rather strange. Just to check, the settings used when you saved the measurement sweep are the same as in the Measure dialog, 48k sample rate, 20 - 20,000 Hz 512k sweep? As an aside, it is best to select the actual input device and input used rather than "Primary capture driver", but it shouldn't affect the measurement.

 

[Krunok]

Yes, settings were the same (20-20K, 512k length). Sample rate shouldn't be an issue with "timing reference" scenario as external playout device could anyhow use resampling, right?

I'll try to reproduce this issue on another comp and let you know how it went.

 

[John Mulcahy]

The sweep should be generated at the sample rate REW is set to, the sample rate setting affects the way the sweep is generated.

 

[Krunok]

The sweep should be generated at the sample rate REW is set to, the sample rate setting affects the way the sweep is generated.

I generated the sweep with 48kHz but DSP plugin in Volumio resamples eveyrthing to 96kHz. Do you think that can affect the listening/recording process in REW?

 

[Krunok]

I got it to work with BT speaker and MusicBee! I think the problem was that I was using 96kHz swep file in this scenario.

 

[Krunok]

It works with Volumio as well, with new 48kHz sweep files. Obviously the previous sweep files were not good for some reason.

 

[Krunok]

Thank you for the assistance!

 

[John Mulcahy]

Phew!

 

[Krunok]

If same thing would happen to somebody else - my guess is that sweep file was incorrectly generated. The moment I generated fresh 48kHz sweep file it started to work as it should.