Questions & Answers

Why do I lose volume and high end by switching main bus from stereo to mono?

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asked Jan 2, 2020 in Studio One 4 by felixolschewski (120 points)

The setup:

  • One channel of acoustic guitar recorded through one microphone, no inserts or FX.
  • This channel is mixed in center position.

Scenario A:

  • I switch the main bus from stereo to mono. The sound does not change. This is to be expected.

Scenario B:

  • The main bus is still in mono mode.
  • I pan the guitar from center to hard left or right. The sound is still heard in the center but the volume changes and I perceive a loss in high end. I expect no change at all, though.

One would expect that switching from stereo to mono basically sums up all channels into one channel which is then routed as an identical stream to both the left and right output. If there is a signal at -6dB hard left and this is added to the total sum (of 0 because in this case there is no other signal) then I expect a total sum of -6dB and, therefore, no loss of volume (or high end).

Since this is a mono signal there should be no potential for phase issues.

Now. The loss of volume can be explained by the so-called Pan Law which, as I understand it, is approximated in different ways by digital systems including DAWs. How that makes any sense if I have an Autopanner on my single channel running in the above scenario is probably a question for the philosophers. I think the effect of the autopanner should be nullified by switching to mono but in reality it will be transformed into a tremolo.

But what about the (perceived) loss of high end? Upon dropping the volume I would rather expect a perceived loss of low end. Surely everything is in order with Studio One. So if any of you could give me an explanation I would really appreciate that.

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