On 2013-02-22 10:59 AM, Joel Alperson wrote in part:
> I have to confess, I'm caught off guard a bit by the recommendation for
> 24/96 files for voice recordings, although given the cost of storage,
> it's probably not that big of a deal to go with that bit and sample
I have become more of a proponent of 48 ks/s for speech recordings from
cassettes since I have a spectrogram shoved in my face on a more regular
basis in iZotope (which I have moved to for cleaning). There's no audio
above 20 kHz coming off these cassettes. It rarely happened back in the
day and that was only within the Nakamichi line (pretty much). I've
given you links of reading at my blog -- there is one article near the
top about the 4 dB ambiguity at 16 kHz...and that was cooked into the
non-standard back in the day. Post-recording HF loss makes that even a
Also, may cassette decks had 19 kHz multiplex filters in them so the
Dolby wouldn't get confused (among other things), but some were not
IASA TC-04 states: ( http://www.iasa-web.org/tc04/key-digital-principles )
> 2.2 *Sampling Rate*: The sampling rate fixes the maximum limit on
> frequency response.When producing digital copies of analogue material
> IASA recommends a minimum sampling rate of 48 kHz for any material.
> However, higher sampling rates are readily available and may be
> advantageous for many content types. Although the higher sampling
> rates encode audio outside of the human hearing range, the net effect
> of higher sampling rate and conversion technology improves the audio
> quality within the ideal range of human hearing. The unintended and
> undesirable artefacts in a recording are also part of the sound
> document, whether they were inherent in the manufacture of the
> recording or have been subsequently added to the original signal by
> wear, mishandling or poor storage. Both must be preserved with utmost
> accuracy. For certain signals and some types of noise, sampling rates
> in excess of 48 kHz may be advantageous. IASA recommends 96 kHz as a
> higher sampling rate, though this is intended only as a guide, not an
> upper limit; however, for most general audio materials the sampling
> rates described should be adequate. For audio digital-original items,
> the sampling rate of the storage technology should equal that of the
> original item.
I mentioned other sampling rates as they are, in my opinion, acceptable
unless these cassettes are the very highest quality AND they are the
inherent built-in sampling rates of reasonable affordable tools that
will get the job done in an acceptable manner. Only the Otari high-speed
digitizer is likely to handle sample rates not related to CD quality.
The 10 kHz upper limit imposed by the 22.05 ks/s of the relatively
inexpensive 8 X British system is a function of the 8 X record option.
It does produce 44.1 ks/s files at 4 X as I pointed out. The question is
whether you want to spend the time considering that the likelihood of a
substantial amount of program material being reliably recoverable much
above 10 kHz from 10,000 cassettes is problematic.
I just looked at the spectrogram of the RE-10 mic demo with a male voice
at http://www.coutant.org/evre10/index.html and the only significant
energy above 5 kHz is in the "S" sibilant sounds "thiS iS..." and that
goes out strong to the upper limit of the file around 15 kHz.
The British ingesting system is targeted towards churches that have a
large sermon ministry on cassettes and want to make this back catalogue
available digitally. I first learned about them through Technologies for
I agree with Bruce Gordon that for Harvard, I would ingest everything at
48 ks/s minimum and most items at 96 ks/s (all at 24 bits) and I'm
trying to move many of my clients to 48 ks/s ingest rather than 44.1
ks/s, but many factors are involved, notably how the client will store
the files. I assume that anyone moving forward with 10,000 cassettes
will develop a way of managing multiple TB of data which is now easy to
do considering the availability of multiple multi-slot NAS units. My
current thinking is that my next NAS disk purchase will be WD Reds which
are optimized for this use on a non-enterprise basis. Attempting to do
this on optical media would be semi-suicidal in my opinion. Remember,
three copies in three different locations if possible.
I just do not see the need if using equipment that performs well at 48
ks/s to ingest at 96 ks/s for spoken word cassettes. Any music deserves
96 ks/s as do grooved media if for no other reason as it helps separate
clicks from program.
> My big question is, what is the easiest way for me to learn to use a
> software package like Samplitude (recommended by Richard Hess)? I've
> seen an instruction manual or two for these types of programs and
> they're massive and seem very complex. Given that for now I'm just
> interested in recording (not editing) material, I'd hope there's an
> easier way for me to get familiar with these products.
You can download a 30 day demo.
For just recording, it is very easy...sort of. Samplitude treats
odd/even pairs as stereo pairs as a default and since the best available
cassette machines are stereo, I strongly suggest ingesting in that mode
and making a decision in post as to which channel you are going to
preserve. You'll find that it may vary through a cassette.
You open a new virtual project (VIP) and select sample rate and number
In the record option menu (red light surrounded by a gear) you select
the formatting of the file name which will be the VIP and the track name
(at least that is my suggestion) AND make sure you're on 24 bits.
In the VIP layout double click the track name and put the file ID in that.
Make certain that the input routing is correct and each track is record
Press record and then start the cassette machines.
At the end, save the VIP...the WAVs are already saved.
I probably left a few things out, but this month's tutorial on the
Samplitude site goes into more details.
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada 647 479 2800
Quality tape transfers -- even from hard-to-play tapes.