Phasing in Cubase Monitoring but not in the recording or Direct monitoring?

Recently I had to get away of my studio equipped with a Focusrite scarlett 18i20 mk2 that I use daily.

Now, I’m using the same laptop with a Scarlett 8i6 mk3 and trying to record an acoustic guitar with a condenser mic.
For some reason, when I tried to monitor from Cubase I hear a very clear phasing issue that I’ve been unable to solve.
-I can record anything and the phasing doesn’t get recorded, so the playback is correct.
-The direct monitoring (interface software) is off, but when I turn it on it sounds correct.
-Is not delay/latency or buffer related issue. It’s phasing, like if there’s two channels with latency trying to monitor at the same time.
-Never had this issue before.
-Cubase and drivers up to date.
-Simple routing from Mono input 1 to stereo output 1-2.
-No loopback or anything like that related.
-Input 1 or 2 give the same result.

*Windows 10
*Cubase 12 up to date 17/08/2023
*Drivers up to date


Do you maybe mix the Direct Monitor with the signal from Cubase?

Phasing is a delay related phenomena. If you hear that in the monitoring chain only, then you introduce some delay to a signal and mix it with the not delayed signal.

As @Martin.Jirsak already wrote, you likely mix the direct monitoring signal with the Cubase monitoring.

I’m trying to make the difference between buffer related delay and a phasing type of delay. The first is just one signal delayed and the second is two signals with one delayed so…
As I said, I’m not mixing the two monitoring options. Interface’s software direct monitoring is off.

Please read carefully before writing.

How did you check this? There is no switch to disable the monitoring inside the Scarlett.

I did, that’s why I think it is a double routing.

Well, there IS a switch inside the “Focusrite Control” software that can mute or not any “Hardware input” you have activated. For direct monitoring you have to activate the input and then let it unmuted. You can switch to mute and there is no sound.

I can verify that there is no double routing as far as it shows whatsoever. It is indeed very strange. That’s why I’m here trying to get ideas. I work everyday on Cubase with a larger focusrite interface, so I know what I’m telling you. This is a newer (mk3) smaller one i got to work when I’m away.

Last thing I tried on Adobe Audition and the very same thing happen. It is very audible that whenever I try to monitor it is like two signals, one delayed come to sound (and not just one delayed like a big buffer). Still no clue. (Tracks are on mono,input buses too)

Activation of direct monitoring fixes the problem?

Inside cubase, in the settings “Direct monitoring” is greyed out.
I already stated why I mean by Direct monitoring, which is monitoring inside Focusrite Control.
By now, nothing fixes the problem.

I had this happen once, with my RME interface. Actually, the direct monitoring wasn’t involved at all : simply, the matrix view of TotalMix (the bundled control software) was showing that, for a reason, my main outputs was receiving both the involved hardware input and Cubase Control Room output. User error…

So, as @Martin.Jirsak and @st10ss, I also think that there must be a double routing occuring somewhere, as a result of your present Scarlett settings. Worth a (double) check…