4 ms·

>For this to work, the left and right signals were recorded in opposite phase. I don't know, but found the following comment in an audiophile/collector forum,

>For this to work, the left and right signals were recorded in opposite phase. I don't know, but found the following comment in an audiophile/collector forum, note the comment about phase. https://www.discogs.com/forum/thread/774378?message_id=7697060#7697060 https://www.discogs.com/forum/thread/774378?message_id=76970... "When Stereo records first appeared circa 1958, it was important that they were NOT played on existing mono equipment, as the two playback modes were incompatible with regards to wear and tear. A mono player would damage the stereo record primarily because a stereo record required the stylus to wiggle up and down as well as left and right. Mono only required left and right, and mono players of the time had little up and down capacity. "Mono record players (or more specifically cartridges and stylii) then incorporated the ability to play stereo records and modern, of the time (late 1960's) players could therefore play a stereo record without damage. At the same time mono records were phased out, so people needed to be assured they could still purchase records (which were only available in stereo) and play them without causing damage. "It has nothing to do with the record, everything to do with the playback equipment. "As a further point stereo records were limited by phase - they needed to ensure that at various critical frequencies there was no difference in phase between left and right (bass is critical), otherwise the stylus might jump out of a groove. Some digital formats have recordings that contain much out of phase information - creating a holographic type impression. If these contain low frequency sounds out of phase, then these need to be modified prior to be prepared for release on a record. "

starkparker 4y ago
This is why there are still mastering engineers who specialize in vinyl. See also https://badracket.com/vinyl-mastering/ https://badracket.com/vinyl-mastering/ for more vinyl-specific mastering concerns.
jlarcombe 4y ago
Yeah the phase thing is quite a pain, I always thought it was just for really low stuff, but a band I was helping out had a master rejected by the pressing plant for excessive out-of-phase audio even when the passages in question weren't particularly 'heavy'. Since then I've been quite paranoid about it before sending masters off, and it's surprising how many mixes have a load of out-of-phase stereo. It can usually be tamed with some M/S EQ but then you miss the spaciousness in headphones...
- eternalban 4y ago
  What causes the phase shifts?
  - jlarcombe 4y ago
    Sorry for delay in replying. Two main causes in my experience: 1. as a deliberate effect, either on its own or as part of a reverb; similarly, some synth sounds have this 'built in' 2. as a consequence of multi-microphone recording, where two microphones are used on the same source but are positioned such that the channels end up significantly out of phase The trouble is that inter-channel phase is one way in which stereo 'works' so it's all a bit of a compromise... this is why there are various tried and trusted spaced stereo microphone techniques that give a sense of spaciousness without introducing too much out of phase content (e.g. ORTF) and often these give a more pleasing result that the coincident-pair (XY) techniques that minimise phase differences. Often in situations where there's lots of sources being recorded at once you can end up with problems. The usual rule of thumb is to ensure that if two microphones are picking up a single source, the more distant one is at least three times the distance of the closer one to the source. A quick way to check this stuff with headphones when positioning microphones is to sum them to mono, reverse the polarity of one of the mics and move them around to minimise the bass cancellation.

starkparker 4y ago

This is why there are still mastering engineers who specialize in vinyl. See also https://badracket.com/vinyl-mastering/ https://badracket.com/vinyl-mastering/ for more vinyl-specific mastering concerns.

jlarcombe 4y ago

Yeah the phase thing is quite a pain, I always thought it was just for really low stuff, but a band I was helping out had a master rejected by the pressing plant for excessive out-of-phase audio even when the passages in question weren't particularly 'heavy'. Since then I've been quite paranoid about it before sending masters off, and it's surprising how many mixes have a load of out-of-phase stereo. It can usually be tamed with some M/S EQ but then you miss the spaciousness in headphones...

eternalban 4y ago
What causes the phase shifts?
- jlarcombe 4y ago
  Sorry for delay in replying. Two main causes in my experience: 1. as a deliberate effect, either on its own or as part of a reverb; similarly, some synth sounds have this 'built in' 2. as a consequence of multi-microphone recording, where two microphones are used on the same source but are positioned such that the channels end up significantly out of phase The trouble is that inter-channel phase is one way in which stereo 'works' so it's all a bit of a compromise... this is why there are various tried and trusted spaced stereo microphone techniques that give a sense of spaciousness without introducing too much out of phase content (e.g. ORTF) and often these give a more pleasing result that the coincident-pair (XY) techniques that minimise phase differences. Often in situations where there's lots of sources being recorded at once you can end up with problems. The usual rule of thumb is to ensure that if two microphones are picking up a single source, the more distant one is at least three times the distance of the closer one to the source. A quick way to check this stuff with headphones when positioning microphones is to sum them to mono, reverse the polarity of one of the mics and move them around to minimise the bass cancellation.