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Jon- I am surprised that "pitching" is being suggested ex post facto as the proper procedure for doing a 78 transfer. The reasons are as follows: 1.The 78 is the only format that varies considerably from the stated number of revolutions per minute. In fact, as you probably know when the 78 was a more prevalent format among audiophiles(1950-60's) many high-end pre-amps like the Marantz 7-C had specific eq curves that were tailored to the playback curve of a particular era or even a particular label! 2. I have never heard older recordings become so natural and mellifluous as when they are played back through a system that is tailored to the distinct playback curve of that era. Likewise, when you hear a "78" that is played back on a variable pitch turntable with the specific speed that the record company employed the entire experience changes. The slightly chirpy, sharp artifacts disappear entirely and in its place is a far less antiquated sound palette. This is akin to watching Keystone Cops films and we laugh at the racing, silliness of the action; this too is a result of the fact that the modern film standard of 24 fps was not employed at that time, but modern film projectors do not allow one to compensate for this analogous discrepancy. 3. The final reason is that the algorithms which are used to achieve this pitch change simply go back and toss out enough samples to make the program the desired speed or length. There is no way that I am aware of that does this in a way that does not damage to the resultant file. In short it does not remove the samples in a way which is sensitive to the music in question. When you do this on a turntable this remains a constant stream of information, no data is lost when the pitch is changed. Essentially doing ananlog pitch change is a lossless change, whereas pitch change in the digital realm necessitates a "lossy" algorithm. 4. For these reasons I believe that (with the exception of the Weiss EQ-1) a really fine analog(Sontec) EQ with an excellent turntable turning at the exact required playback speed will in general reveal far more musical results than attempting either eq or pitch changing in the digital domain. I think it is unlikely to change in the near future. Mutatis mutandis, aa On Wednesday, August 27, 2003, at 06:31 PM, Mike Richter wrote: > At 03:48 PM 8/27/2003 -0600, Jon Noring wrote: >> [Cross-posted from 78-L to the ARSC mailing list for their learned >> opinion.] >> >> >> Some of the discussion in this thread (on Pitching 78s) talks about >> pitching during the digital transfer of source material such as 78rpm >> records. My present view (subject to being changed with a persuasive >> argument) is that pitching should not be a worry during the transfer >> itself (just get it close.) Once digitized, during the restoration >> process the recording can be pitched digitally using sound processing >> software (effectively by resampling). >> >> Some may argue that digitally pitching a digital audio file will >> introduce errors (from what is effectively resampling) that we need to >> worry about and thus pitching should be done during transfer, but am I >> right that the "bit-error" introduced in doing this "resampling" is so >> minimal as to not even worry about? >> >> (Also, in reality, is 44.1K or 48K sampling more than adequate for >> all 78 digital restoration? Or should one double sample, e.g. at 96K, >> for digital restoration purposes, and only at the end of restoration >> to resample downward to 44.1K for "Red Book"?) > > In my opinion, pitching should be done at recording if possible to > avoid > the time and inaccuracy of resampling. The time is, of course, a > function > both of the speed of your system and the quality of the sampling > algorithm. > Using a program such as CoolEdit, which allows you to adjust quality, > you > can hear and (more significantly in some ways) see in the spectrum the > effects. Oversimplifying, resampling 48 ksps to 44.1 ksps introduces > components at the difference 'frequency' of 3.9 ksps and multiples. The > higher the quality of interpolation (or extrapolation in the other > direction), the lower the amplitudes of those components. > > NOTE: It's been forty years since I worked with z transforms. If > someone is > up on the matter today, please provide the math to replace my > memories. <G> > > Note, too, that the error introduced here is not LSB or fractional > bits as > in most transforms but actual introduction of spurious audio. > >> On a related topic is equalization. Here, when I talked with George >> Morrow earlier this year (he passed away in late May), he commented >> that it is much better to set the proper analog equalization during >> transfer than to do it digitally (but he was of the opposite opinion >> with regards to speed/pitch, as I note above.) I'd like comment from >> the experts here on 78-L and ARSC on this topic. > > Unless the starting signal-to-noise ratio is extraordinary - say, 90 > db - > the losses due to modest equalization are at the fractional-bit level. > In > the case of severe equalization, I'd suggest that if the maximum > effect (db > difference between max and min equalization) plus SNR of the source is > substantially less than the 96 db of redbook audio, digital EQ is fine. > Thus, if you have 4 db/octave over the usual range (20 - 20K Hz) with a > good open-reel tape as input, you would approximate as 4db x 10 + 60 > db = > 100 db and digital EQ will cost SNR. Of course, with very low-noise > input > and ADC, capturing and processing at 24 or more bits, the loss would be > buried when the signal is finally reduced to 16 bits. > > > Mike > [log in to unmask] > http://www.mrichter.com/ > > Sincerely, Aaron