REW Beta Release REW V5.20 beta 12

[John Mulcahy]

Not so many changes in beta 12, in the eternal hope of getting to a V5.20 release

The RTA "DR" figure has been replaced by a figure for the A-weighted noise plus distortion in the current Y axis units. Using this figure together with the maximum level (for which distortion is better than -40 dB) allows a dynamic range figure to be generated. For a meaningful N+D result per AES17-2015 the system should be driven with a 997 Hz sine wave at 60 dB below the maximum input level.

A basic scope data export capability has been added in a format that should be amenable to saving as a csv file and importing in a spreadsheet. It contains the raw, normalised sample data at the sample rate in use when it was captured. The sample value corresponding to one volt is included in the header information.

Here are the bug fixes, including one that could result in REW stopping during the impulse response calculation part of a measurement:

• Bug fix: Predicted response was not updated correctly when loading a measurement with filters
• Bug fix: Measurement sweep could be shorter than intended for some combinations of start frequency, end frequency and total length
• Bug fix: RTA file processing would not give a result for files the same length as the FFT length
• Bug fix: When processing files the RTA sample rate remained at the rate of the first file processed
• Bug fix: The All SPL button to "Average the Responses" was disabled when an averaged measurement was selected
• Bug fix: An exception could occur while calculating the impulse response

 

[SPo]

Hi there,

i am using a Steinberg UR22mkII with actual drivers and firmware in Win10 64Bit. I want to measure the impedance of my speakers and built a cable like mentioned in your help file (using the headhones output with a 100 ohms resistor).

While trying to calibrate the impedance with open ends i get the following error:

I guess every steps unti the calibration are fine - this happens using the JAVA or the ASIO driver of the UR22mkII as well:

Levels are OK:

After pressing "Calibrate Impedance" i get this:

After pressing "Start" get this:

Is this a problem of the soundcard or any bad beta behaviour ? I already changed USB ports and sample rates - but there are no enhancements.

SPo

 

[John Mulcahy]

Is there something else in the path to the speakers? I only get a 0.4 us timing offset with the UR22 mkII using ASIO, about 0.02 samples at 44.1 kHz.

 

[SPo]

Hi John,

No - there is no Hub or anything in the path. And i didnt configured any delay (didnt found the asio option).

I am using a Core i7 8086K and there i wouldnt expect a bottlneck there (checked system load with processexplorer - nearly nothing).

SPo

 

[John Mulcahy]

Check the ASIO buffer setting, 1024 samples should work OK.

 

[SPo]

no changes :

I tried all all buffer sizes and i get only with the "32 samples" setting a change :

 

[John Mulcahy]

I have the same latency figures for the 1024 sample buffer setting, though my ASIO driver is 1.10.2. Hard to understand how it is possible to get such a timing difference between the inputs.

 

[SPo]

Is there a possibility to adjust this delay in software ?
Because it is constant it would be easy to set it once and its done?

Maybe its because i`ve got several soundcards installed ? A Soundblaster, a miniDSP nanoshark USB driver, and a Realtek Driver... ?

...bunch of questions...

SPo

EDIT: i need all Soundcards enabled - so i wouldnt like to deactivate some...
EDIT2: i use the same setup with ARTA and the special switch-box, and it is working nicely... but i like the REW GUI and features much more...

 

[John Mulcahy]

I have 4 interfaces connected, not counting the on-board stuff. Shouldn't make any difference.

The offset could be compensated out, but I've never encountered an interface with more than half a sample delay between channels. Having more than a sample offset suggests something is very wrong somewhere. If you swap around the input connections (and swap the selections in REW) does the -14 sample offset become +14 samples?

 

[John Mulcahy]

By the way, if you just make a loopback SPL measurement on the card does everything look normal?

 

[SPo]

Switching the inputs doenst make any difference for impedance calibration - always (MINUS) -14:

 

[SPo]

deleted

 

[SPo]

Loopback:

 

[SPo]

And here comes an uncalibrated impedance measurement with warning (done several times with same results, open ends with 100 ohm resistor):

 

[John Mulcahy]

The offset between the channels seems to be there, the loopback shows it versus the reference and the spikes in the open circuit measurement are at frequencies which would have cancellations corresponding to a 14 sample delay. I have no idea how it is possible to have a 14 sample delay between the input channels or how to fix it. I have made a change for the next beta to allow the calibration even with such a large offset, but it really, really shouldn't be there.

 

[SPo]

Hi John, thank you!

Is there any chance to test a nightly build (as you just released a new beta and the next seems to come in July) ??

Anyways, i will try the older ASIO driver you are using, too - if i can find it...

SPo

 

[tankm]

5.20 beta 12 sweep measurement result is different from earlier beta and 5.19. Tried multiple measurement, same result. Can't attached the mdat file. Sorry.

 

[John Mulcahy]

Measurements look the same for me:


How are you making your measurements? If you use a sweep saved as a WAV file you must use a file saved from the version you are using to make the measurement.

 

[tankm]

Hi John, You are right on using different version generated test tone.

All measurements are done using external saved WAV file. Below are what I found.

Graph below is measurements from 5.19. The numbering match to legend.
1. Test tone from 5.20b12 from 15Hz to 20kHz - This is the bad one. Happens when using start freq below 20Hz.
2. Test tone from 5.20b12 from 20Hz to 20kHz - OK but SPL is lower
3. Test tone from 5.19 from 15Hz to 20kHz - OK. Match to (4)
4. Test tone from 5.19 from 20Hz to 20kHz - OK. Match to (3)

 

[John Mulcahy]

The sweep isn't "bad", it has different characteristics, per this item in the release notes for V5.20 beta 12:

• Bug fix: Measurement sweep could be shorter than intended for some combinations of start frequency, end frequency and total length

The sweep in beta 12 onward will have slightly better signal-to-noise ratio for some frequency spans. To measure with 5.20 beta 12 use a sweep saved from V5.20 beta 12.

 

[EmuMannen]

i am using a Steinberg UR22mkII with actual drivers and firmware in Win10 64Bit. I want to measure the impedance of my speakers and built a cable like mentioned in your help file (using the headhones output with a 100 ohms resistor).

While trying to calibrate the impedance with open ends i get the following error:

...

I got the same problem with a Steinberg UR22mkII but with a timing offset of around 254 sample periods! I am using Windows 7 with the latest version of UR22mkII firmware and Steinberg ASIO drivers (I get the same error if I use the Java drivers in REW). I am using REW V5.20 beta 22 but had the same problem with the previous version of REW.

Now I don't know if I can trust any measurements I have done with REW and the Steinberg UR22mkII.

 

[EmuMannen]

I got the same problem with a Steinberg UR22mkII but with a timing offset of around 254 sample periods! I am using Windows 7 with the latest version of UR22mkII firmware and Steinberg ASIO drivers (I get the same error if I use the Java drivers in REW). I am using REW V5.20 beta 22 but had the same problem with the previous version of REW.

I think I have found the problem but I don't know if it is a bug or a feature. There is a "timing offset" field on the "Make a measurement form". It is visible when "Type" is "SPL" but it is hidden when "Type" is "Impedance". I had this set from a previous SPL measurement. The error dialog about channel timing offset during impedance calibration dissapered as soon as I set the value of the "timing offset" field to zero. It was not obvious that this filed could have an impact on impedance meassurments since it is only visible when "Type" is set to "SPL".

 

[John Mulcahy]

That's a great observation EmuMannen, thanks! Definitely a bug (fixed for the next build).