Your advice, as always, is greatly appreciated. Yes, I do tend to try
and optimize when I have an album master, but many tapes I receive are
long-form (more than a few are 1/4-track) and I think I'm doing well if
tape saturation occurs at about -1 or -2 dBFS in the transfer process.
Also, I would never do a transfer where the converter noise is obvious.
No matter where we increase gain if the gain staging is properly
analyzed and addressed the noise source should be some combination of
tape and first stage of the tape repro preamplifier--normally it is
almost all off the tape. I worry if I do not hear a large jump in noise
when I hit play.
I am certain you have done your share of tapes with wildly varying
levels that go from "in the noise" to saturation. Since I normally do
not have a budget on a per-tape basis to scan for highest peaks, it is
with these tapes that I am conservative. Album masters and other "high
quality" tapes are a different matter (and a different budget).
It would be interesting to hear the context of the types / content /
quality of the tapes the original poster is digitizing.
On 2012-10-19 2:02 PM, Mark Donahue wrote:
> Couple of quick comments from someone who does a fair amount of re-issue
> mastering from material that has been "Domain Transferred" as part of
> 1) Don't normalize levels. spend the time to get the levels right on the
> transfer. Gain staging is your friend. I regularly see stuff that was
> transferred at peak levels of -12 to -18 then normalized. While in the
> digital domain the process is pretty transparent, it is in the analog
> domain that there is a problem. The analog noise floor of converters is
> usually somewhere around -100 and typically has an audibly different
> character when compared to the analog noise from the tape machine. When you
> add 12 to 18 dB of gain the noise floor becomes audible. It's really not
> that hard to get the peak levels into the top 6 dB. Get a good quiet
> attenuator to adjust the levels feeding the converters. This stuff is
> really not rocket science.
> 2) Get to know the safe operating levels for your equipment. We've
> calibrated out converters for the past 30 years to +18dBu=0 dBFS. We tend
> to use professional equipment and test the devices to see where the device
> clips. Most professional analog gear has at a minimum peak level of +22
> before clipping. Many Semi pro and consumer devices are incapable of
> getting to +18 without clipping or distortion. You need to find out where
> your equipment clips and leave the appropriate headroom. Again, gain
> staging is your friend.
> 3) Operating levels for tape machines are all relative. (Unless calibrating
> for Noise reduction). It's the same if someone calibrates to 185 and peaks
> at +3 an the VU or 250 and peaks at 0 VU. On tapes without tones it is
> most important to get the azimuth correct. Calibrate level and EQ to the
> MRL and then align the azimuth for peak high frequency on the tape to be
> transferred. Equalization can be corrected later with very little
> degradation. For folks dealing with tapes from the EU, learn to hear the
> difference between NAB and CCIR.
> These are just a couple of my pet peeves. I could go on for hours.
> I'll step off my soap box and let the conversation continue.
> All the best,
> Mark Donahue
> Soundmirror, Inc.
> Boston, MA
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Quality tape transfers -- even from hard-to-play tapes.