Issue: crackling noise after in output file

[devac99]

Hi,
I'm trying to do some recording with my Sony Alpha 6400. My target is to record my guitar playing passing from my Neural Quad Cortex (48Khz) as input guitar, to my UAD Apollo 8 audio interface and then passo to OBS.
I've watched arount YouTube and did the best settings for 4K videos. Till now everything looks fine, I can play correctly and record everything. The problem is in the output file (.mp4), usually after 1:00 I start hearing a cranckling distorted noise, but I can't understand why it happens.
I've setted OBS sample rate to 48Khz as well, in the Encoder settings the rate control is CBR, and the bitrate is 45000 kbps.
In the Output settings, under the audio tab, these the recording settings: recording format .mp4, Video Encoder Apple VT HEVC Hardware Encoder.
I've followed the best practices but something is still wrong but I can't figure out what.
I've ask some help with it, I'm new with video recording and I really appreciate some help, thank you

 

[XLCOLDJ]

Just a few questions/thoughts:

Is it the same result when you record MKV and remux instead of recording directly to mp4?
Which inputs from the UAD are you exposing to OBS via the UAD I/O matrix? MON L/R, or...?
Do you get the same crackling if you bypass the NQC and connect the guitar directly to the UAD Hi-Z input?
Are you using a balanced cable (TRS or XLR) between the NQC and the UAD input?
Which "Global Audio Devices" do you have added on the Audio tab in OBS?

 

[devac99]

Ok I solved the problem of the noise simply bypassing Logic, the initial chain was this:
Neural QC (UBS cable) -> Logic Pro -> OBS
Now is only: Neural QC (USB cable) -> OBS
This solved the disturbing noise, Logic seems that overload processed data and creates that noise.

I have another problem now: the quality of the sound is very low, but in the Output section under the tab Audio I've setted the track 1 as 320 bitrate. Actually I'm not using a balanced cable, do you think that could improve the sound? cause while I play I don't have any problems, neither when I do some records on Logic.
In the "Global Audio Devices" currently I have only Desktop audio as default, but my input comes from "Audio input capture" in the sources

 

[XLCOLDJ]

The crackling is gone, but the sound quality is still not good in OBS recordings? What's 'bad' about it?

Maybe the input is being doubled in OBS. If you go to the audio devices and "Unhide All" you can double-check that only one signal is coming through. If I unmuted the Screen Capture, Mic and UAD all at once, I could end-up hearing myself three times.

Actually I'm not using a balanced cable, do you think that could improve the sound? cause while I play I don't have any problems, neither when I do some records on Logic.

The balanced cable would only matter if you were using it to connect the Neural QC to the UAD Apollo. I didn't know that it was a USB device. If you have everything sounding right without OBS, you should be able to get that exact quality in OBS.