I'm getting distortion when I record (for example) interface channels 1 and 2 as dual mono tracks in CbB. I do not get this distortion using Reaper or Studio One. I have found it true with any pair of interface channels seen to CbB as a stereo pair. Quick example:
In CbB the first to channels of my interface may be addressed as:
input 1 left mono
input 1 right mono
input 1 stereo
If I record two microphones into interface channels 1 and 2 into a CbB stereo track as input 1 stereo I don't get distortion.
If I record two microphones into interface channels 1 and 2 into a pair of CbB tracks using the sources input1 left and input1 right respectively I do get distortion.
I'm really hoping it's a trick I'm missing, hence the post.
This experiment demonstrates the distortion artifacts found when recording low frequency signals in
adjacent tracks within a stereo pair (by this I mean one microphone in left input 1 and the other in
right input 1).
An interesting note is that adjacent channels outside a stereo pair (e.g.: input 1 right and input 3 left) do not have the distortion artifact.
Description of the test bed:
The source is a upright bass playing pizz (sloppily) through a 2 octave chromatic scale
The interface is a Focusrite Clarett 8Pre X (Thunderbolt)
Two SM57 microphones on a stereo bar positioned 12" in front of the source
One microphone is labled A and the other B
Microphones are connected to inputs described in scenarios
Microphone preamp gain set to 12 o'clock on channels under test
No parameters changed between tests except as noted in the table below
Recorded at 96/24
Exported at 96/24 no dithering
No meter registered above -26 dB, (interface, focusrite control, DAW) while recording or during playback
The quality of the distortion is akin to an extreme EQ boost with a narrow Q where you can hear the filter ringing at resonance.
The distortion is present in both tracks - it is not an artifact of playing both tracks simultaneously.
Outside that directly demonstrated by this test, level doesn't seem to change whether or not distortion is present.
I have reproduced this problem recording amplified electric bass and also drum kit with strong low frequency components (e.g: low toms and bass drum, low power chords on guitar) with a variety of microphones (SM57, RE-20, K-2, SM25, R10, ...).
In all observed cases the source recorded on both channels was the same (as in the case of this audio example) or similar (as in the case of low toms and bass drum where this is always bleed).
Test Mic A Mic B Result
--------- ----- ----- --------------------
One 1 2 distortion
Two 1 3 no distortion
Three 7 8 distortion
Four 6 8 no distortion
Five 2 3 no distortion
DAWS involved in testing:
Hardware involved in testing:
multiple Presonus interfaces (from FireStudio to StudioLive 16.4.2)
multiple Focusrite interfaces (from Scarlett/USB to Clarett/Thunderbolt)
The audio is too large to drop here - a link to the writeup, a picture of the recording setup, and a CbB project that demonstrates the audio artifacts may be found here:
Thanks for any info.