IDM Mailing Archive

My apologies for being stupid. I am obviously not a Professional. I was imagining 300-odd multiple tracks, each starting as an individual spiral among 300-odd possible, interwoven spirals on the record. On another note -- and while this (like every other one of my posts) has nothing to do with idm in particular -- is it possible to change the handedness of the spiral groove on a record, so that a track starts from the inside and works its way out? Are the dynamics of the needle on the groove such that this inversion would cause technical problems, i.e. is the needle engineered with chirality in mind: v <- needle --------------------n-------------------- <- record less relative force this side -> v <- more force the other side -- as the needle travels along the groove -- so the engineers think, "ah, let's make this half of the needle last longer, as it will encounter more stress"? Are the individuals pressing records thinking along the same lines? To all the DJs, Sorry, :: Alex

On Wed, 2 Sep 1998, Alex Reynolds wrote:

quoted 4 lines My apologies for being stupid. I am obviously not a Professional.

> My apologies for being stupid. I am obviously not a Professional. > > I was imagining 300-odd multiple tracks, each starting as an individual > spiral among 300-odd possible, interwoven spirals on the record.

Those would certainly spiral inward pretty sharply!

quoted 14 lines On another note -- and while this (like every other one of my posts) has

> On another note -- and while this (like every other one of my posts) has > nothing to do with idm in particular -- is it possible to change the > handedness of the spiral groove on a record, so that a track starts from > the inside and works its way out? Are the dynamics of the needle on the > groove such that this inversion would cause technical problems, i.e. is the > needle engineered with chirality in mind: > > v <- needle > --------------------n-------------------- <- record > > less relative force this side -> v <- more force the other side -- as > the needle travels along the groove -- so the engineers think, "ah, let's > make this half of the needle last longer, as it will encounter more > stress"? Are the individuals pressing records thinking along the same lines?

Not really, in fact, there is an adjustment called "anti-bias" or "anti-skating" that tilts the tone arm such that, on a frictionless surface (ie, not touching the record or a record with no groove) can make the tonearm weighed to move toward the left or right. The function of this is to defeat skipping tendecies. In your example, you must remember that the needle is intersecting the record at a tangent and the curve of the groove vs the centripital force is not very strong, especially since the tonearm is very light (depending on how you set it.) I imagine that the engineers don't have to design the needle to be different on each half. Ectomorph, on Interdim. Transmissions has a track that not only starts on the inside, but ends in a lock groove in the middle of the record right next to the lock groove that ends the track that plays from the outside in. My question is: has anyone made a record with two parallel grooves that spiral inward between each other that have different tracks with the same bpm that have the their cue points line up, such that if the needle skips to the other track (the one in parallel, not one groove ahead or behind) it is still in time and in sync? Whew! solenoid

That sounds almost like you're describing some sort of error correction on a piece of vinyl... Such a two-tracked record could be played on a deck with a two-needle arm, the distance between needle tips equalling the distance between groove valleys. The advanced deck would be less susceptible to bumps *and* able to take the two signals and subtract noise from either, like a pair of chromosomes. Something like that could be "complete without surface noise"... :: Alex

quoted 5 lines My question is: has anyone made a record with two parallel grooves that

>My question is: has anyone made a record with two parallel grooves that >spiral inward between each other that have different tracks with the same >bpm that have the their cue points line up, such that if the needle skips >to the other track (the one in parallel, not one groove ahead or behind) >it is still in time and in sync? Whew!

__________________________________________________________________________ Alex Reynolds Distributed Support Specialist Department of Biology School of Arts & Sciences Computing University of Pennsylvania Philadelphia, PA email:reynolda@sas.upenn.edu phone:215.573.2818

Seems like the differences in the movement of the two needles might cause problems. Maybe you could offset the cue points of the two grooves and just use two tonearms. This brings up another of my brilliantly pointless questions: Has anyone ever dj'd a setup that has two tonearms playing one record such that you could crossfade back to the quarternote that "just happened" and do some slapback echo business? Obviously this is the same as having two copies of the record and two turntables, but I had to ask, 'k? No stone left unturned, solenoid On Thu, 3 Sep 1998, Alex Reynolds wrote:

quoted 26 lines That sounds almost like you're describing some sort of error correction on

> That sounds almost like you're describing some sort of error correction on > a piece of vinyl... > > Such a two-tracked record could be played on a deck with a two-needle arm, > the distance between needle tips equalling the distance between groove > valleys. The advanced deck would be less susceptible to bumps *and* able to > take the two signals and subtract noise from either, like a pair of > chromosomes. Something like that could be "complete without surface > noise"... > > :: Alex > > >My question is: has anyone made a record with two parallel grooves that > >spiral inward between each other that have different tracks with the same > >bpm that have the their cue points line up, such that if the needle skips > >to the other track (the one in parallel, not one groove ahead or behind) > >it is still in time and in sync? Whew! > > __________________________________________________________________________ > Alex Reynolds Distributed Support Specialist > Department of Biology School of Arts & Sciences Computing > University of Pennsylvania Philadelphia, PA > email:reynolda@sas.upenn.edu phone:215.573.2818 > > >

solenoid@europa.com <------+

quoted 4 lines Has anyone ever dj'd a setup that has two tonearms playing one record such

> Has anyone ever dj'd a setup that has two tonearms playing one record such > that you could crossfade back to the quarternote that "just happened" and > do some slapback echo business? Obviously this is the same as having two > copies of the record and two turntables, but I had to ask, 'k?

i was at a fsol show (isdn) in santa monica, ca. there was an isdn connection to NY from santa monica, and then to london (where fsol were). after fsol played, there was an ambient "jam" between the east and west coast folk (pretty fucking amazing actually). one of the djs (either terre thaemlitz or tetsu inoue id guess) used 2 tone arms somehow.. but one was from a different player, just moved over so it could be used on the playing record that was on another player. or at least thats how i remember it. ive been known to fabricate shit in my head.. so someone back me up or knock me down, but at least fill in the gaps! regardless, it was a fine night. chris.

Couldn't "true" quad sound be done this way, then? On Thu, 3 Sep 1998, Alex Reynolds wrote:

quoted 26 lines That sounds almost like you're describing some sort of error correction on

> That sounds almost like you're describing some sort of error correction on > a piece of vinyl... > > Such a two-tracked record could be played on a deck with a two-needle arm, > the distance between needle tips equalling the distance between groove > valleys. The advanced deck would be less susceptible to bumps *and* able to > take the two signals and subtract noise from either, like a pair of > chromosomes. Something like that could be "complete without surface > noise"... > > :: Alex > > >My question is: has anyone made a record with two parallel grooves that > >spiral inward between each other that have different tracks with the same > >bpm that have the their cue points line up, such that if the needle skips > >to the other track (the one in parallel, not one groove ahead or behind) > >it is still in time and in sync? Whew! > > __________________________________________________________________________ > Alex Reynolds Distributed Support Specialist > Department of Biology School of Arts & Sciences Computing > University of Pennsylvania Philadelphia, PA > email:reynolda@sas.upenn.edu phone:215.573.2818 > > >

solenoid@europa.com <------+

What's considered "true" quad sound? What vile beast has four ears? <g> The easiest, no-brainer approach: four channels in via two needles on two grooves, four channels out via RCA (or whatever you use). However, I think that as far as the movies go, you can encode multiple channels in "stereo" (two) channels, which is already available from a record -- technically, surround sound (FL, C, FR, RL, RR) is accomplished by phase differences put in the two channels. Front and rear signals are separated by having a "front" wave cancel a "rear" wave via superposition, and vice versa. (This, according to the Dolby decoder manuals I read whilst running a film house back in school.) Apparently, the way that the sound is optically encoded on the film doesn't affect the poorer theatre's ability to serve regular stereo, or even vanilla mono. So with records as they are, you'd go with an encoder chip before pressing the master and a decoder chip on each turntable to get four channels out. Or you could go with the nasty, two-armed monster. :: Alex P.S.: With 35mm film, you only have so much space to put a soundtrack before you start squeezing the picture frame, so Dolby's older solution was good in that you only needed enough room for the two channels. In fact, SDDS and Dolby Digital use the space between the cog holes (!) to store the optical soundtrack, and DTS -- I think -- uses a special laser disc player which carries the soundtrack for the entire movie.

quoted 13 lines Couldn't "true" quad sound be done this way, then?

>Couldn't "true" quad sound be done this way, then? > >On Thu, 3 Sep 1998, Alex Reynolds wrote: > >> That sounds almost like you're describing some sort of error correction on >> a piece of vinyl... >> >> Such a two-tracked record could be played on a deck with a two-needle arm, >> the distance between needle tips equalling the distance between groove >> valleys. The advanced deck would be less susceptible to bumps *and* able to >> take the two signals and subtract noise from either, like a pair of >> chromosomes. Something like that could be "complete without surface >> noise"...

__________________________________________________________________________ Alex Reynolds Distributed Support Specialist Department of Biology School of Arts & Sciences Computing University of Pennsylvania Philadelphia, PA email:reynolda@sas.upenn.edu phone:215.573.2818

quoted 4 lines On another note -- and while this (like every other one of my posts) has

> On another note -- and while this (like every other one of my posts) has > nothing to do with idm in particular -- is it possible to change the > handedness of the spiral groove on a record, so that a track starts from > the inside and works its way out?

mult already mentioned the O.S.T. 12" that does this. others off the top of my head are: v/a - Too Many Clowns (throw) 1st track plays inward and ends. 2 lock grooves in the middle. 3rd track plays inside-out hmm. . Serotonin always seems to have a couple pressing oddities. they really throw you the first time you try to play it. . :) .jeff / chris. .do not condemn the judgement of another because it differs from your own . you may both be wrong .