REW on Various versions of MacOS and processors behaving differently / Not working at all

[rajopotamus]

I have two MacBooks.

Mac #1 - 2018 MacBook Pro with i7 intel processor, 16gb ram, usb-c ports. MacOS Sequoia 15.7.1

Mac #1 works well on REW 5.31.3. SPL is measured accurately and the program is stable and outputs audio to the proper channels being measured

My only known issues with this computer is that when upgrading to the Beta versions of 5.40; the SPL meter starts becoming erratic and starts to register my noise floor anywhere between 80-175db rather than 30-34db on my Umik2. I also have a phone with a NIOSH meter and an SPL meter than confirm the noise floor in the mid to low 30s. I am using an optical USB-c cable to the mic. No matter how many times I unplug, restart REW, etc etc it just never consistently holds a steady SPL level with the Beta versions of REW. As soon as I go back to 5.31; everything goes back to working as it should. I haven't been able to figure that why that is behaving that way. I just figured Id ask if anyone else noticed this behavior?

Mac #2 - 2025 MacBook Air with M4 apple silicon, 16gb ram, usb-c ports. MacOS Sequoia 15.7.1 and MacOS 26.0.1 Tahoe

Mac #2 is much more erratic in its behavior with REW On MacOS Sequoia 15.7.1 and REW 5.31.3; the spl registers correctly, however sound does not output from the correct output channels in REW. Sound will sometimes come out of no channels and sometimes a few channels but not all. I tested the channels with my AVP's (htp-1) signal generator and all channels work properly. Addiitionally; if I use a different app such as Apple Music or YouTube; the channels work properly. For some reason it's only REW (as far as I know on my machine) that won't output correctly despite being configured properly with the HTP-1 with the output and UMIK2 as the input. Midi setting are matched at 48 kHz 24 bit.

When I updated to MacOS 26.0.1 and using REW 5.31; all channels except the center channel outputted properly with no change in settings. The center channel still will not output. SPL registered properly. Updating REW to the beta resulted in the SPL registering improperly as it did on my other MacBook #1 on the betas and there was still not output to the center channel. Other apps and the AVR outputted to the all proper respective channels.

I did read that many MacOS users were having some issues with USBC and audio with Tahoe 26; however the issue was prevalent in Sequoia 15.7.1 on MacBook#2 for both REW 5.31.3 and 5.40 beta; but worked completely fine on MacBook #1 on Sequoia 15.7.1 and REW 5.31.3 only.

My guess is there is something going on with MacOS; but I wanted to bring the issue to the forums attention in case anyone has found a solution

 

[John Mulcahy]

UMIK-1 and UMIK-2 both behaving normally for me on 15.7.1 with the latest 5.40 beta.

 

[rajopotamus]

UMIK-1 and UMIK-2 both behaving normally for me on 15.7.1 with the latest 5.40 beta.

Would you mind sharing what type of Mac machine you’re using?

Do you have a direct hdmi connection into your machine or are you using some sort of usb c hub?

 

[John Mulcahy]

2020 M1 Mac Mini, measurements mostly USB-C to an ADI-2 Pro FS R. I don't use any HDMI connections for audio.

 

[rajopotamus]

Ok so I tried a different usb-c cable and that resolved the SPL differences through the various versions of REW on my 2025 MacBook Air. The mic is recognized instantly regardless of cable. However the optical cable only behaves properly with 5.31 and not the betas. The standard wired usb c cable works fine with both. I am not sure why that would even be the case but I thought id just report my findings.

I tested different HDMI cables and for this there has been no solution to no audio out of the center speaker with REW. I posted below the photos of my HTP-1 web UI that shows the MAC output locked on and the audio and video formats.

I also posted my MAC sound settings and MIDI settings. When I play the test tones from the speaker configuration window in the MIDI configuration, the center speaker does indeed play a test tone; however it will not with the signal generator in REW. The signal generator outputs to all my other channels properly.

I am curious if you have any thoughts are to why either scenario could be occurring? Do you believe it to just be a hardware/OS issue with the MacBook that will requires a fix from apple?

Thank you always for responding so quickly as always! I don't mean to be a bother or nagging; the software is awesome. I just thought if I'm running into this issue id bring it up int he forum in case others are or anyone has any ideas as to how to resolve it. My gut feeling is that it's an Apple issue; however the optical usb cable working well on one version of REW and not the other and the test tones playing in the configuration but not REW is really throwing me for a loop.