REW oddity

[ruffrecords]

I have been doing some final frequency response tests on a tube mixer I am building. For testing I run REW on a little fanless mini PC running Win10 using a Scarlett 2i2 interface. So I can certainly see comfortably past 20KHz I usually set the sample rate to 48KHz (I have some peaking 19KHz EQs in this mixer). As I am testing the entire mixer signal chain, I am measuring at the master outs which means I can use the monitor outs to actually listen to the sweeps as they happen. When I first started the test I noticed nothing unusual in the sweep sound. But on the frequency response display there were some very large glitches. After fist suspecting the mixer I connected the 2i2 output to its input and repeated the test with similar large glitches. I was surprised I had not head anything so I switched the REW sig gen to 1KHz sine wave and listened to the 2i2 output on headphones. To my surprise there were frequent irregular drop outs of the 1KHz signal. I suspected the PC might be underpowered so I turned off everything I could ( including 6 instances of the Win10 browser) and checked the CPU duty which was only about 10% but still the problem remained. In desperation I switched the sample rate to 44KHz and bingo, everything was a steady as a rock.

So right now I am not sure if the issue is with REW, WIndows of the Scarlett (it is an old one).

Cheers

Ian

 

[zamproject]

Hi Ian

Don't know how it is on Win, but here the SR setting in REW set soft only, without warning if miss match with HW.
Be sure to set same SR at REW, ADDA hardware driver, and Win ?
Or maybe another audio app taking over the SR setting ?

If you can't hear it I guess it's a recording issue, not a playback one ?

Cheers
Zam

 

[Tubetec]

Look at buffer settings on the Scarlet interface software , increase the value , 64 128 256 512 etc
check to see if audio stabilises .


The other thing you must do , in my opinion , with any version of Windows thats to be used for audio ,
Remove the system sound scheme forever , delete it , select none , dissable Windows start up chime while your in there too. Windows system sounds can often cause a change of sample rate from the one selected on the Interface and DAW , resulting in unpleasent noises and dropouts because stuff has to get resampled and otherwise crapped all over by Windows Audio services .

I highly reccomend you try HBCD based on Win 10 PE as a test bench for audio ,
worked right out of the box for me with Reaper/REW/SSL2 Asio drivers . Theres none of the distractions of standard Win10 , If your more comfortable with a XP or WIN7 type experience ,you'll feel instantly at home .
By default it has no system sounds , never asks to update or needs to connect to internet , it does have networking and browsers built in if you want , ethernet will almost certainly work out of the box , Wifi is usable too but you may need to extract the WIFI driver from the WIN10 installation .
I use a program called Driver double to extract then restore the drivers to the PE after boot up .

Its very simple to set up on a USB based storage device of more than 4GB,
you download the HBCD iso and use a software tool called Rufus to create the bootable recovery media,
Select boot device menu at start up on the PC and boot via the USB ,

I havent done extensive listening tests with WIN PE yet , but all the signs so far are its a very fast ,low overhead opperating system that runs on almost any PC hardware , very well suited to handling audio in near real time ,

 

[Tubetec]

Ive run up a few PC's tailored to audio testing and recording over the years where I completely dissabled the Windows audio service , that means browser audio is broken but Asio drivers install and work within the DAW regardless . It cuts out a layer of processing within Windows and improves latency times .

 

[cyrano]

I would first suspect the USB power, unless, of course if the Scarlett 2i2 is externally powered.

 

[ccaudle]

In desperation I switched the sample rate to 44KHz and bingo, everything was a steady as a rock.

Do you have access to a Mac or Linux to check? Windows does not have a native USB audio class 2 driver, so it has always been in a weird position with high quality USB interfaces. You often have to install a vendor driver to get access to all of what should be considered basic features.

 

[ruffrecords]

Do you have access to a Mac or Linux to check? Windows does not have a native USB audio class 2 driver, so it has always been in a weird position with high quality USB interfaces. You often have to install a vendor driver to get access to all of what should be considered basic features.

Yes I have access to Linux.

However, I just switched over to ASIO drivers and rebooted and it seems fine now. I switched sample rate to 88KHz and I can see right up to past 40K without and glitches.

Cheers

Ian

 

[Tubetec]

By default REW sets up a Java based driver , usually 44.1k 16 bit .
You need to select Asio ,then your interface then sample rate in the drop down lists , once you have that done REW will always start with the proper driver and sample rate as long as the USB device is present .

 

[BluegrassDan]

REW has been acting glitchy lately on my MAC. Bizarre.

 

[Tubetec]

https://www.roomeqwizard.com/changehistory.html#revisionlist

Maybe check on which revision of REW your running ,

Did you perform any MAC firmware updates lately ?
I frequently find threads where later updates cause problems with older machines regarding audio stabillity .