Sound issue
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From: Jaimie Vandenbergh on 28 Dec 2009 06:20 On Mon, 28 Dec 2009 11:07:56 +0000, adrian(a)poppyrecords.invalid.invalid (Adrian Tuddenham) wrote: >J. J. Lodder <nospam(a)de-ster.demon.nl> wrote: > >> Rob <patchoulianREMOVE(a)gmail.com> wrote: >> >> > On 26/12/2009 12:51, Rowland McDonnell wrote: >> > >> > > >> > > It is a technical error, these days, to mix the typical audio recording >> > > in a fashion optimized for vinyl discs, >> > >> > In what way is audio recording optimised for vinyl? Do you mean mixing, >> > or some form of filter? I only ask as someone interested in recording >> > *from* vinyl, and asithappens, listening to LPs. >> >> A better way to put it would be that the audio signal to be put on disk >> is constrained by the limitations of vinyl and PU elements. > >I would have said "constrained by the limitations of groove geometry and >the intended playback equipment". > >The vinyl itself does impose some limitations, but most of the problems >would still occur if they had used "Shellac" (slate dust with shellac >binder), "Acetate" (cellulose nitrate), gelatine, wax, rubber, >chocolate, thermosetting resins, catalytic resins or any of the hundreds >of other materials which have been tried over the past century. Chocolate was actually tried? Cocoa with a (non-edible!) binder, or some other method? (I love this physics/engineering/acoustics geekery) Cheers - Jaimie -- Once I drove so fast that my friend, who was pregnant, started having Lorentz contractions. "Ahah," you might ask, "but how far apart were they?" - Adam Fineman, rgrn
From: Adrian Tuddenham on 28 Dec 2009 06:42 Jaimie Vandenbergh <jaimie(a)sometimes.sessile.org> wrote: > On Mon, 28 Dec 2009 11:07:56 +0000, > adrian(a)poppyrecords.invalid.invalid (Adrian Tuddenham) wrote: > > >J. J. Lodder <nospam(a)de-ster.demon.nl> wrote: > > > >> Rob <patchoulianREMOVE(a)gmail.com> wrote: > >> > >> > On 26/12/2009 12:51, Rowland McDonnell wrote: > >> > > >> > > > >> > > It is a technical error, these days, to mix the typical audio recording > >> > > in a fashion optimized for vinyl discs, > >> > > >> > In what way is audio recording optimised for vinyl? Do you mean mixing, > >> > or some form of filter? I only ask as someone interested in recording > >> > *from* vinyl, and asithappens, listening to LPs. > >> > >> A better way to put it would be that the audio signal to be put on disk > >> is constrained by the limitations of vinyl and PU elements. > > > >I would have said "constrained by the limitations of groove geometry and > >the intended playback equipment". > > > >The vinyl itself does impose some limitations, but most of the problems > >would still occur if they had used "Shellac" (slate dust with shellac > >binder), "Acetate" (cellulose nitrate), gelatine, wax, rubber, > >chocolate, thermosetting resins, catalytic resins or any of the hundreds > >of other materials which have been tried over the past century. > > Chocolate was actually tried? Cocoa with a (non-edible!) binder, or > some other method? I don't know the exact composition, but it was obviously done as a gimmick and intended to be edible. I do know of one which is still in (uneaten) existence, so there might be a chance of analysing it if anyone really needed to know. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
From: Jaimie Vandenbergh on 28 Dec 2009 14:55 On Mon, 28 Dec 2009 11:42:16 +0000, adrian(a)poppyrecords.invalid.invalid (Adrian Tuddenham) wrote: >Jaimie Vandenbergh <jaimie(a)sometimes.sessile.org> wrote: > >> On Mon, 28 Dec 2009 11:07:56 +0000, >> adrian(a)poppyrecords.invalid.invalid (Adrian Tuddenham) wrote: >> >> >The vinyl itself does impose some limitations, but most of the problems >> >would still occur if they had used "Shellac" (slate dust with shellac >> >binder), "Acetate" (cellulose nitrate), gelatine, wax, rubber, >> >chocolate, thermosetting resins, catalytic resins or any of the hundreds >> >of other materials which have been tried over the past century. >> >> Chocolate was actually tried? Cocoa with a (non-edible!) binder, or >> some other method? > >I don't know the exact composition, but it was obviously done as a >gimmick and intended to be edible. I do know of one which is still in >(uneaten) existence, so there might be a chance of analysing it if >anyone really needed to know. Fab. I wonder if a chocolate disk could be a substrate for an aluminium CD foil? Next-gen digital choccies! Oh, probably not - the substrate on a real CD is clear, and the laser reads the foil through it. Flipping it would make focus impossible. Boo. Cheers - Jaimie -- "The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man." - George Bernard Shaw
From: J. J. Lodder on 28 Dec 2009 17:29 Jaimie Vandenbergh <jaimie(a)sometimes.sessile.org> wrote: > On Mon, 28 Dec 2009 11:07:56 +0000, > adrian(a)poppyrecords.invalid.invalid (Adrian Tuddenham) wrote: > > >J. J. Lodder <nospam(a)de-ster.demon.nl> wrote: > > > >> Rob <patchoulianREMOVE(a)gmail.com> wrote: > >> > >> > On 26/12/2009 12:51, Rowland McDonnell wrote: > >> > > >> > > > >> > > It is a technical error, these days, to mix the typical audio recording > >> > > in a fashion optimized for vinyl discs, > >> > > >> > In what way is audio recording optimised for vinyl? Do you mean mixing, > >> > or some form of filter? I only ask as someone interested in recording > >> > *from* vinyl, and asithappens, listening to LPs. > >> > >> A better way to put it would be that the audio signal to be put on disk > >> is constrained by the limitations of vinyl and PU elements. > > > >I would have said "constrained by the limitations of groove geometry and > >the intended playback equipment". > > > >The vinyl itself does impose some limitations, but most of the problems > >would still occur if they had used "Shellac" (slate dust with shellac > >binder), "Acetate" (cellulose nitrate), gelatine, wax, rubber, > >chocolate, thermosetting resins, catalytic resins or any of the hundreds > >of other materials which have been tried over the past century. > > Chocolate was actually tried? Cocoa with a (non-edible!) binder, or > some other method? > > (I love this physics/engineering/acoustics geekery) It might well be possible to play it, after a night in the freezer, Jan
From: Rowland McDonnell on 29 Dec 2009 04:28
Adrian Tuddenham <adrian(a)poppyrecords.invalid.invalid> wrote: > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > > Adrian Tuddenham <adrian(a)poppyrecords.invalid.invalid> wrote: > > > > > J. J. Lodder <nospam(a)de-ster.demon.nl> wrote: > > > > > > > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > [...] > > > During the era of changeover from mono to stereo when both types of > > > record were on sale, Decca produced two completely independent mixes for > > > the two issues. > > > > ISTR reading that more than Decca produced two different mixes, and not > > merely for the change-over period (which never really ended, did it?). > > John Culshaw, Decca's A&R man, gives a detailed account of the period in > his book "Putting the Record Straight". Righto - ta. > > > The limitation on the vertical channel with a grooved medium was more > > > due to the slew rate than to pure amplitude, so it was the high > > > frequencies that were badly affected. > > > > Werl, yeah. Anyway, doesn't the RIAA curve deal with the bass amplitude > > problem completely? > > It certainly prevents the groove inter-cutting which would result from > constant-amplitude recording characteristics, Uhuh. > but the majority of the > bass problem arises from pickups having low compliance stylus mountings. Oh! I see - I didn't know that. > The earlier mono cartridges (e.g. TC8) had almost no vertical compliance > at all. Righto. Stereo was coming in at about the time I was born, so I'm not really up with this sort of thing. > Heavy vertical LF modulation would make them jump, Whee! <grin> Yes, I can dig that, man. > so a record producer > who made stereo recordings with the idea that they might be played on > cheap mono 'compatible' equipment, would have to make sure they were > really compatible by constraining the LF to horizontal modulation. AH! The light dawns - yes, okay, that's a good technical reason. > Even > then, really heavy modulation or a frequency which coincided with a > badly-damped arm resonance could well fling the pickup out of the > grooves sideways; <snigger> Good grief. > so the problem was mainly one of cheap and nasty > playback equipment, not one of which direction the bass was recorded. Righto - but there was plenty of cheap-and-nasty kit around, wasn't there? Mind you, now I understand why the old stereo record pickups included instructions for mono wiring - you'd want a stereo cartridge for mono electronics if you had stereo recordings to play, bearing in mind the above, wouldn't you? > A different problem was caused by playing records with high levels of HF > on cheap equipment. The effective stylus tip mass was high and placed > acceleration loads on the groove walls which broke them down (see > John/Jean Walton's articles in Wireless World). Uhuh - gotcha. Coo! > The owner of the cheap > equipment didn't find this a problem because it wouldn't reproduce the > resulting distortion anyway - but when the damaged records were > subsequently played on good equipment, it was revealed that they had > been ruined. Uhuh. > > > With really good studio monitor speakers and a proper stereo recording, > > > the 'bass' can appear to be be directional, mostly because the harmonics > > > give the position away. > > > > Oh! > > > > > (Example: The recent Radio 4 broadcast of the BBC Philharmonic > > > Orchestra playing the "Upstairs-Downstairs" theme showed a very clear > > > stereo image with quite noticeably directional bass.) > > > > I'd love to have heard stereo imaging from my bedside radio-alarm clock > > ;-) > > On my studio monitors it was fairly breathtaking. As it was a voluntary > tribute to the composer and was done 'on the cheap' at the end of > another recording session, I suspect they used a single pair of > close-spaced mics and didn't do anything to 'improve' it. ... Other > recording engineers please note. My other half works near enough to the audio-visual people at her uni to find out part of the problem behind modern recording staff: management seem to have the idea that all your problems can be solved by just pressing a button on the computer and so expensive highly skilled highly trained staff are no longer needed to produce output. All the techie types scream in horror at this attitude, of course. Doesn't help. Management just carries on - and this is at a university, which is supposed to be training the next generation. Training. Huh. Since when were universities supposed to /train/ anyone? Bring back the polys, I say. Rowland. (who's got one degree from a uni and one from a poly) -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking |