At 03:25 PM 2007-04-01, Eric Jacobs wrote:
>Having a good understanding of the minimum error in the disc cutting
>system (ie. just how flat a frequency response could be achieved, and
>how accurate are the test discs used to calibrate the cutting systems)
>will help make specifying minimum RIAA accuracy for reproduction less
>arbitrary. If disc cutting systems were accurate to 0.1 dB of RIAA
>from 20 to 20 kHz when properly set up, then I think the Neumann
>constant is worth looking into more deeply. If disc cutting systems
>were accurate to 1 dB of RIAA, then the Neumann time constant is a far
>I do believe it is a slippery slope to say that just because there are
>many other elements in the reproduction chain that introduce far
>bigger errors, we should ignore the potential influence of the Neumann
>time constant - especially if the Neumann time constant could be easily
I believe that we will be very lucky to be holding +/- 1dB from 20 to
20 kHz with the tape component--in fact, holding +/- 1 dB from 50 to
15 kHz across the board would have been quite excellent. In just ten
tapes from a major broadcaster known for their quality, I saw one
tape way outside +/- 1 dB at 15 kHz and each session varied within
the range while tapes from the same session were very close. These
were 15 in/s tapes.
While that begs the issue of direct-to-disc recordings, I would
suggest that the vast majority of recordings made from perhaps 1950
until the end of the LP era were made via tape.
Yes, it's a slippery slope and that's why I suggested that you
contribute an article about this to my blog where we can document all
of these little gotchas. It doesn't have to be long, but I will set
up a separate topic as I plan to add more tape ones in the future --
or if you write it on your own website, I'll make a note of it and link to it.
And oh, the chemistry issues. Tapes, like the plumbing in "The Money
Pit", are not getting better with age.
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.