Phasing (1 Viewer)

[Jimmy Magee]

Right, a nice technical question for anyone who's interested...if you try to reproduce a stereo effect by copying the track left and right and delaying one side, you could get phasing if you play the thing back through mono (because you're now basically just playing the thing on top of itself, but delayed). What I'm wondering is this: will whether it phases or not just depend on the frequencies of the notes you're playing and the delay? I would imagine so, e.g. if you're playing a note that's, say, 100Hz (which means the peaks will occur every 10ms), and your delay is 10ms, the two waveforms will line up exactly, so you won't have any phasing, but if your delay is 5ms, the two will cancel out completely...is this then behind the common recommendation to use (I've heard both, maybe one is better than the other?) 18ms or 25ms delays for this purpose, since maybe any of the normal frequencies one uses will not phase with these delays...?

 

[egg_]

Pretty much any musical note is not one pure frequency, but the sum of a load of different ones. So when you delay a track and add it to itself you're unlikely to lose notes entirely ... however cancelations at certain frequencies will have the effect of a filter (a delay of 5ms will cause cancelations at 100Hz, 200Hz, 300Hz etc) and so will change the sound of the note

I'd imagine 18 or 25ms delays are recommended more for the sound of the delay itself rather than because they create less phasing (ANY delay will cause phasing - less noticeable if it's really long though)

 

[dubh in seattle]

....yeah what egg said It does seem that anything above +/- 20ms gives the sound of a discrete delay (you can hear the delayed event as a separated thingy, not a phasey combined tone...) a guy I worked with on a fillum told me to always shoot for odd-valued delays when trying to do faux stereo, as the chance of freq cancellations is diminished. You might achieve the desired effect by very slightly detuning one side (like 1-3c). Are you looking to stereofy a whole 'band' type mix, or more like a single instrument? Let's talk at de brawlrheum, I'm on at the library at Ilac centre (skint) so can't stay on!!!

 

[Jimmy Magee]

Danke, danke. Won't be at the Brawlrheum unfortunately, so I'll miss out on the ol' Wild Turkey I guess . It's single instruments I be trying to do...might give that detuning thing a lash. What did the Beatles do for their-double tracked vocals? I know that in the early days they just recorded two takes, but later went for automatic double-tracking, which I'm guessing just put a delay on a copy of the vocal, and panned them to the same place (generating phasing in other words).