Quality rules regarding sample rate

Special Interest Groups Podcasting
1

Hi,

I have to deal with material with mixed sample rates:
a) external recording (lectures) with 32 kHz (from the external conference program ZOOM, I have no influence on the sample rate, it’s ZOOM)
b) self spoken recordings (Short headlines) with 32 kHz or 44.1 kHz
c) music clips with 44.1 kHz

Later on I like to export the project to mp3 with quality set to Medium.

Normally I start with importing track a) into the project → which sets the project rate to 32 kHz
Then I do recording b) which results also in 32 kHz.
Then I import music clips with 44.1 kHz.

Up to this point it seems ok to me.

But then I run into troubles like this:

  1. ReplayGain needs >= 44.1 kHz to work
  2. some other VST-plugIns also needs at least 44.1 kHz

My solution could be:

  • resample all 32 kHz tracks to 44.1 kHz
  • set the project rate to 44.1 kHz

My questions are:

  • is that a recommended way?
  • with respect to target medium quality mp3 → is upsampling and then sort of downsampling by the lame encoder resulting in a big qualtity loss?

Thanx for your help
Ralf

2

Pretty much.
I would recommend changing the Project Rate first. The “Resample” command will then default to 44100 (because it defaults to the project rate), which saves a few key presses.

Note that if you were not using effects that require 44100 Hz, then you could just change the Project Rate and leave the tracks at 32000. The exported file will be at the same rate as the “Project Rate” (regardless of the track sample rate).


Resampling a track to a higher sample rate has virtually no effect on the sound quality.
Encoding to MP3 always reduces the sound quality a bit.

3

Thanx Steve,
that made it totally clear!