REW clipping at very low levels

[jobby001]

Hi, I use rew 5.2 with HDMI and umik and has been working well until I recently installed the software for a minidsp ddrc-24.
I installed the minidsp software and ran dirac through the same laptop and then went to take some rew measurements but they were all over the place.
I have since removed everything from the chain so back to laptop umik av receiver rca to subwoofer but all my subwoofer measurement stop due to clipping at very low levels.
I now notice that under asio devices I have asio4all v2 (which is selected) but in the drop down there is now an option for minidsp asio driver which was not there before so must be part of the Minidsp ddrc install.
I have tried a fresh install of rew and still the same.
I could try installing all the minidsp software but I want to make sure I am not missing something easier first.
Has anyone come across this before?

 

[John Mulcahy]

Dirac sets the UMIK gain to maximum, which applies 24 dB of gain, so may need to put that back to the 0 dB setting. Beyond that make sure the UMIK is still selected as the input.

 

[jobby001]

Thank you so much for your help John.
So in preferences, I can see and select input as Umik -1 Gain 18db. The calibration file for my Umik is selected.
I look at section Configuring Windows Audio Recording Devices in the rew instructions and go to sound and recording settings
Select the Umik as device and go to properties and the level is set to 100% currently.
As I am a windows 10 user I understand that I should change this to 81%
Am I missing anything?

 

[John Mulcahy]

If you right click on the volume control you can set it to read in dB, set it to 0 dB, about 53%.

 

[EarlK]

If you right click on the volume control you can set it to read in dB, set it to 0 dB, about 53%.

John,

Right Click where ? ( REW or Windows ? )

FYI, I believe I've tried all possible areas ( since you first mentioned it ) and have never been able to change the percentage readout to one of db's .

On Win10 Pro > latest Beta

 

[John Mulcahy]

Here, right click on the track or the value:

 

[EarlK]

Thanks John

 

[Deadly Mix Studios]

Dirac sets the UMIK gain to maximum, which applies 24 dB of gain, so may need to put that back to the 0 dB setting. Beyond that make sure the UMIK is still selected as the input.

I can't stop the clipping and I'm going insane because the clipping only exists in REW. Neither the output, mic, nor loopback is clipping on the console, the AD-DA face, nor DADMan software. I needed to deliver these measurements to Dolby this afternoon and, 12 hours later, I still don't have a single measurement.

System Info:
Windows 10 Pro
REW (latest version updated today)
Dayton Audio EM66
Using Avid MTRX Studio as ADC and DAC for the measurements
Interface is Marian Clara E 512×512 Channel Dante PCIe
7.2.4 PMC monitors w/ George Augspurger custom 18" subs on Bryston 14B

I've tried everything and the clipping doesn't go away. Also pops up after that window that the signal to noise is too low.
I've tried a million configurations and settings. About 35 inputs, 20 outputs, 3 preamps, 4 cables, different combinations, gain up, gain down, volume up and down, nothing seems to make any difference.

Perhaps the biggest indicator that the issue is in REW somewhere is that it clips even when all the physical connections are unplugged.
I've watched the meters in DADMan and saw the meters where they should be and even made them too low, but the Level Window and the one in the Measurement window always show solid red aside from a slight flicker here and there.
I had to tell it to stop stopping every time it overloads to even see what's going on.
I tried changing the level in the measurement window from -12dB to -30dB and all the way down to -180dB. All that changes is the signal becoming in audible and dropping in the meters in DADMan and the face of the MTRX.

what in the world is going on?? The studio was tuned over the course of a couple months, the system is calibrated, I just need these measurements to double-check everything before I send this data to Dolby; data that I need because I don't have the data from when the studio was built anymore.

 

[John Mulcahy]

If the levels clip when making a measurement that is typically due to monitoring being active. If the input levels clip when REW isn't producing a signal then something else is going on. Are you using the Avid ASIO driver? Can you attach a screenshot of your REW soundcard preferences?

 

[Deadly Mix Studios]

Dirac sets the UMIK gain to maximum, which applies 24 dB of gain, so may need to put that back to the 0 dB setting. Beyond that make sure the UMIK is still selected as th

Here's a new window I don't think I've seen so far. Says the Soundcard measurement varies by 78dB between 20Hz-20kHz so the measurement may not be valid. None of this makes sense.

If the levels clip when making a measurement that is typically due to monitoring being active. If the input levels clip when REW isn't producing a signal then something else is going on. Are you using the Avid ASIO driver? Can you attach a screenshot of your REW soundcard preferences?

The interface/driver in use is the Marian Clara E Dante PCIe card. The MTRX Studio is normally used as a monitor controller that just happens to have inputs. I'll get so screenshots as soon as I get back to the studio

 

[John Mulcahy]

By driver I mean the choice made in the REW soundcard preferences, which can be Java or ASIO.

 

[Deadly Mix Studios]

 

[Deadly Mix Studios]

 

[Deadly Mix Studios]

 

[Deadly Mix Studios]

This probably would've been easier to do one of those things like Waves does where they take over the computer remotely, but hopefully the pictures give adequate information.
As you can see, the clipping actually gets WORSE when the connection to any converters is severed.

The buffer doesn't make a difference. Buffer at 16 is too small to function, at 32 the issue remains all the way past a buffer of 4096 and it eventually gets too long to function properly but the point of those shots was to show that no buffer setting makes any difference. I thought to try that because of the clocking pop-up I'd received from REW that asked me to check that the sample rates were all the same. They are correct. REW, Clara E, and MTRX Studio are all at 48kHz.

You can see the meters in REW clipping while the meters for the MTRX Studio in DADMan show no signal at all.

Trouble shooting late last night I was able to get the real-time level analysis in the measurement window to go from looking solid (like the picture where the connection to the MTRX is severed in Dante Controller) to the jagged image it is now, like in the picture where the connection is linked in Dante Controller; but I still can't take a measurement and all that blue appears to be saying the noise floor would be too high even if I did decide to measure with the clipping that remains

 

[John Mulcahy]

What is shown on the REW level meters when you are not generating any output and not trying to measure?

 

[Deadly Mix Studios]

I think I'm getting somewhere now. The issue is starting to look like a compatibility issue of some sort. I can't confirm yet, but tis looking like REW may be incompatible with Dante PCIe cards or something along those lines. I switched from the PCIe to Dante Virtual Soundcard and it stopped shoving REW's meters into the red. Unfortunately, I activated 1/3 smoothing at one point and can't find where to take it back off. I wanted to see the measurement in a more typical orientation to see if there would be something I'd notice that gave me an idea of what was going on that I hadn't thought of (I was getting desperate throwing hail marys lol) and now I can't turn it off to see what's going on so that I can set everything up correctly and see if I'm getting the right measurement now.

 

[Deadly Mix Studios]

What is shown on the REW level meters when you are not generating any output and not trying to measure?

With measurement window open, the analysis window was clipping. Whenever level window was open, it was buried. Preference meters black after resetting things then clipping if any other windows were open

 

[Deadly Mix Studios]

 

[John Mulcahy]

That looks good. You're way ahead of me, bypassing the Dante was next on my list

In the Analysis preferences, frequency response calculation there's an option to choose a default smoothing for measurements, perhaps you changed that. You can change the smoothing for measurements in the Graph menu.

 

[Deadly Mix Studios]

I need to remove smoothing to look more closely because that curve seems a little non-flat for a $5k converter looped through Mogami XLR and an even higher-end custom DB25 from Caulfield Cables designed with the specs being "ignore the cost, just make the best cable physically possible".

 

[Deadly Mix Studios]

I'll check there. One moment

 

[John Mulcahy]

Be mindful of the graph range for the soundcard cal measurement, the whole span is only +/-3 dB so those variations are actually tiny.

 

[Deadly Mix Studios]

Thank God. That wiggly line was from a previous measurement made before resolving the issue. As you can see, the new measurements are flat. Thank you so much for your help. Even though I found it troubleshooting, it probably would've taken a lot longer if I hadn't had the opportunity to show the problem, which helped me slow down and organize my thoughts. Thanks for the help with the smoothing too. I really appreciate you being so available.

 

[John Mulcahy]

It looks flat because the SPL axis span is now about 400 dB instead of 6 dB, keep an eye on the figures on the graph axis. You can change the span using the Limits button above the graph. The original plot was absolutely fine and normal for an analog interface, better than most.