Print

Print


Cleaning up the inbox, I found this kind explanation, somehow missed in
June. Thank you, John. I had heard about this, but forgot the term, since
the last time I aligned a tape machine was in 1999. My MRL tape is stashed
away.

In the same thread, Michael Gray challenged a couple of us to look closer at
EMI LPs vs. early CDs to see if the perception that the CDs (some at least)
were shy on bass is valid. Jamie Howarth offered to do analysis. I've kept
this in mind. Best I could do from my modest collection is Klemperer's
Beethoven 5, an old Angel/Capitol pressing (S35843, Red spine/baby-blue
label) vs. the first CD reissue (CDC 7 47187). A/B'ed with a rough match of
levels, the surprise is how CLOSE they sound to each other.

One comparison isn't enough, of course, and there isn't a heck of a lot of
low frequencies on either version. My general impression was from when I had
access to an extensive range of the EMI catalog in both formats. That's long
gone now, sadly. Happily, I have a much better hifi than in 1985 and digital
playback has made great strides since then. While looking for comparisons, I
did find one fascinating item in old and new digital remasterings:
Barbirolli's V-W Tallis Fantasia. Hearing the old English String Music CD
reissue vs. the 2000 version in the Great Recordings box set is interesting.
I think the differences are way beyond what could be attributed to
differences in A-D converters. (Well, yeah, sure. Fifteen years, lots of
changes. Maybe a different source.) It was worth the effort - the newer one
is much better, IMO. Check it out if you can. I don't have it on LP.

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of John Chester
Sent: Monday, June 03, 2013 11:15 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Bass less reissues from England

At 08:26 AM 6/3/2013, Carl Pultz wrote:
>Um, er, - - What? I've never heard of fringing compensation. Please 
>explain, Sir.

See
http://home.comcast.net/~mrltapes/mcknight_low-frequency-response-calibratio
n.pdf

If the master tape has no tones, and (or) LF playback EQ is set using a
full-track alignment tape without compensation for fringing, the actual LF
response will be too low.

The LF problem is exacerbated if the alignment tape has only one LF tone at
100 Hz (a lamentable recent trend -- false economy, IMHO).  Setting 100 Hz
to the same level as 1 kHz is rarely the correct answer.  If the LF tone was
50 Hz, error would be much smaller.

If playback is being aligned using tones on the master tape, and the only LF
tone is 100 Hz, same problem.

Once upon a time, most tape machines could record -- but now many are
playback only.  If the machine can record *and* the track width of the
record and playback heads are the same *and* the track width of the tape to
be played matches the playback head, setting LF record-playback response as
flat as possible is usually the correct answer.  This should be done with a
continuous frequency sweep, or a method that plots response at 1/3 octave
intervals or less.

For a playback-only machine, accurate LF calibration requires a DIY
alignment tape whose track width matches the track width of the tape you
want to play (which hopefully matches the track width of the playback head).
This tape should have tones at 1/3 octave intervals or less to give a
reasonably accurate picture of head bumps.

Graphs showing head bumps at http://www.endino.com/graphs/ Shows why setting
LF response at any single frequency is often a bad idea.

-- John Chester