recording stereo sounds diff than left and right

[Timz2387]

I want my tracks in stereo and I know you can record in mono and then switch to stereo. But if I record something in mono, copy and paste it into another track, and then combine them into a stereo track, it sounds better than if I just record in stereo in the first place. Does this make any difference with the final master mix??? Stereo sounds exactly the same as mono unless i copy and paste....does this make any sense??

[kozikowski]

Two track mono and stereo can be really different. For example, you always get a reliable signal if you use the mono copy/paste method. The two signals will always add up, etc. etc.

If you record in stereo, you are at the mercy of the stereo services delivering the show to the computer. If they're wired wrong, you can get a significantly damaged show -- and still have the blue waves look reasonable.

For example, here's a sound test I did. The fourth segment is intentionally damaged. If you magnify the blue waves enough times, it's obvious I damaged the phase of the sound, but the casual observer would never figure this out. This clip played on a mono system has no segment four.

http://www.kozco.com/tech/LRMonoPhaset4.wav

Koz

[whomper]

I want my tracks in stereo and I know you can record in mono and then switch to stereo. But if I record something in mono, copy and paste it into another track, and then combine them into a stereo track, it sounds better than if I just record in stereo in the first place. Does this make any difference with the final master mix??? Stereo sounds exactly the same as mono unless i copy and paste....does this make any sense??

makes a big diff
look at the many articles on stereo miking techniques
and which are compatible with mono and which are not
and the various tradeoffs between xy ab ortf nos jecklin yada yada

studios will often record separate tracks (many not just two) and combine them. you can get good sounding stereo that way if you know what you are doing. but they will not sound the same as an xy stereo mike recording everything at once. note that studios pan the various tracks to create a wide stereo field.

the results with a wide multi instrument performance and a small single instrument will differ a lot depending on the technique.

with your approach you will not hear real stereo if you have a wide source with multiple instruments. your two mono tracks will likely result in a point source not stereo.

[Trebor]

... if I record something in mono, copy and paste it into another track, and then combine them into a stereo track, it sounds better than if I just record in stereo in the first place.

If the double mono tracks, (the "copy and paste" job), are slightly out of sync (a few samples) you will have inadvertently created a pseudo-stereo track which will sound different from true mono.

[kozikowski]

<<<slightly out of sync>>>

I did that. I failed to home the cursor before I pasted the track.

Freaky.

Koz

[Trebor]

<<<slightly out of sync>>>

I did that. I failed to home the cursor before I pasted the track.

Freaky.

Koz

Don't blame youself, I think Audacity 1.3 sometimes isn't keeping the tracks in perfect sync ...
If you make a mono pair, then invert one of the tracks, and "make stereo pair" they should cancel out (silence) but sometimes they don't.
The waveforms show perfect antiphase alignment, but the fact you can hear sound means they ain't exactly sync'ed.

[steve]

If you make a mono pair, then invert one of the tracks, and "make stereo pair" they should cancel out (silence) but sometimes they don't.

I can't reproduce that. Perhaps that is a sound card driver issue?

[Trebor]

I just tried the "invert one of a mono pair" with sound generated by audacity (a sweepdown) and the result was silent, as it should be.
However when I tried this with a gospel track, attached, there no cancellation, no silence, the music was full volume.
(NB: the gospel track was originally 41000 resampled to 22050, I think here lies the problem).

Gosple, mono pair, one is inverted, so this antiphase should be silent but isnt.wav

(412.4 KiB) Downloaded 62 times

Gosple, mono pair, one is inverted, so this antiphase pair should be silent but isnt.png (105.37 KiB) Viewed 1527 times

If you want to replicate what I did …

1. Create a mono track by splitting a 44100Hz stereo track and discard one.

2. Redefine the single track as “mono”, rather than “left” or “right”.

3. Resample the 44100 mono track to 22050Hz.

4. Using copy and paste, make a copy of the mono track and invert it.

5. “Make stereo track” from this mono pair.

The result: an apparently antiphase pair which isn’t silent, but should be.

Update: it is the resampling causing this effect.
After repeating steps 3-5 on the mono sweepdown I mentioned at the start of this post, the antiphase pair is no longer silent.

[steve]

5. “Make stereo track” from this mono pair.

The result: an apparently antiphase pair which isn’t silent, but should be.

No it shouldn't be silent unless you are monitoring in mono. You should have "anti-phase" audio from left/right speakers if monitoring in stereo.

If you do steps 1 to 4, then that should (and does in my tests) produce silence (or near silence for 16 bit audio)

With the Gospel track, if you use "Split to Mono", then you will get the expected silence.

[Trebor]

Ahh now I get it:
antiphase stereo is full volume (just sounds slightly different from regular stereo)
antiphase dual mono is silent.

My mistake. Thanks Steve.