Mixing down from 24/88 to 16/48 problem


I am mixing down a song recorded in 24/88 to 16/48 and I get this distortion all over the track especially noticeable in quieter parts. The recording is listenable but it is there. It is not there when I am listening to the 24bit recording and it appears during the mixdown. It is impossible to mixdown songs for listening because of this.

Does this ring a bell with anyone?

Also, when I am recording in 24/88 mode the playback vu-meter’s first and the fourth pillar jump red about +20db but the second and the third pilars are fine - no distrotion audible. What is this about? I repeat: I hear no distortion despite this.
Here is a photo

Is it possible that you have a problem in the recording curcuit? The VU meters are indicating that something is wrong. You might try a recording and reverse the track assignments and see if the track problems show up on the other side of the recording. Also, I guess you are sure your sound card is made to handle the 88 and 48 settings.

My soundcard is Steinberg’s MR816x so I guess quality wise this should do the job. Are you referring to some specific soundcard settings? Currently the soundcard is set to record in 24/88 mode but I don’t think this should affect when doing a mixdown in ntrack to 16/48?

Maybe if I change the sample rate of the soundcard from 88.2 to 48 it should affect the mixdown process in ntrack? Although I cannot see why that would be.

So, I changed the sample rate from the soundcard from 88.2 to 48 and did a mixdown: the distortion/noise went away BUT another kind of a sound problem appeared in the playback especially audible in the quieter parts. It is hard to explain what it sounds like but it went away after I changed back to 88.2 sample rate. This is annoying if it means I can’t record in 88.2 and then mixdown to 48.

Also, if I mixdown just changing the bit depth from 24 to 16/88 no problems appear in the sound quality.

I am not sure why you are having the probelm. did you try reversing the ionputs to get the recording/VU error on theopisite side?
I am not sure why you are mixing down to 48. I guess you know that Cds require 44.1 x 16 to play. Recording at 24 is a good idea ( the increased bit debth helps avoid cliping) and I have had no problem mixing that down to 16 - however, I guess I can’t judge as I usually do the dither in Sony CD Architech. Have you tried different dithering settings? It may be the dithering that you are hearing. Dithering introduces a small amount of noise into a recording that are out of human hearing range and then “throws” them away when the file is converted ( someone else can explain this better) but you might be hearing that noise on playback - but the fact that the VU meters show clipping on record bothers me. If changing sides to record does not fix things, try recording at 24/96 and see what happens. Maybe even 24/44.1 and see what happens.

I am quite sure it is not dithering that is causing the problem. I rarely use dithering as I am not sure how to properly handle it. What do you mean by reversing inputs?

From your first post:
"Also, when I am recording in 24/88 mode the playback vu-meter’s first and the fourth pillar jump red about +20db but the second and the third pilars are fine - no distrotion audible. What is this about? I repeat: I hear no distortion despite this. "
what ever you have plugged into first and fourth inputs move them two second and third. IE. swap 1 and 4 for 2 and 3 and vis versa.
NOt using dither May be the problem: The following is from Wikopedia - search for Audio Dithering
In digital processing and waveform analysis

Dither is often used in digital audio and video processing, where it is applied to bit-depth transitions; it is utilized in many different fields where digital processing and analysis are used — especially waveform analysis. These uses include systems using digital signal processing, such as digital audio, digital video, digital photography, seismology, RADAR, weather forecasting systems and many more.

“The premise is that quantization and re-quantization of digital data yields error. If that error is repeating and correlated to the signal, the error that results is repeating, cyclical, and mathematically determinable. In some fields, especially where the receptor is sensitive to such artifacts, cyclical errors yield undesirable artifacts. In these fields dither results in less determinable artifacts. The field of audio is a primary example of this — the human ear functions much like a Fourier transform, wherein it hears individual frequencies. The ear is therefore very sensitive to distortion, or additional frequency content that “colors” the sound differently, but far less sensitive to random noise at all frequencies.[citation needed]
Digital audio
Main article: Quantization (sound processing)

In audio, dither can be useful to break up periodic limit cycles, which are a common problem in digital filters. Random noise is typically less objectionable than the harmonic tones produced by limit cycles.

In 1987, Lipshitz and Vanderkooy pointed out that different noise types, with different probability density functions, behave differently when used as dither signals, and suggested optimal levels of dither signals for audio.[8][9]”

I’d like to point out I have been using n- track for years and this problem has never been there before. This is my first project with the Steinberg - n- track combination, though.
The vu-meter goes crazy even if I just pop in one input say to the 8th input of the soundcard. So I doubt that is the problem.
I’ll see if I can get a sample of the problem later on if this doesn’t ring bell with anyone.

I have been able to succesfully convert the mixdown files to 24/48 mp3 using CDex encoding. For some reason n- track messes the 88.2 -> 48 encoding.