<div style="color:black;font: 12pt Arial, Helvetica, sans-serif;">Since it keeps the total bias fluxivity more constant, the physical location where it no longer switches the remanent magnetic field on the tape (the recording zone) should remain <span style="text-decoration-line: underline;">more</span> stable, not less. In non-HX recording, the location will move in response to high levels at high audio frequencies.
<div><br>
</div>
<div>Bill Whitlock<br>
<br>
<br>
<div style="font-family:arial,helvetica;font-size:10pt;color:black">-----Original Message-----<br>
From: Alan Garren via ProAudio <proaudio@bach.pgm.com><br>
To: Bill Whitlock <engineer_bill@verizon.net>; proaudio <proaudio@bach.pgm.com><br>
Sent: Tue, Feb 11, 2020 11:13 am<br>
Subject: Re: [ProAudio] HX Pro was :FeralA - Recordings released encoded with Dolby A<br>
<br>
<div id="yiv5840493414">
<div>
<div>yes, I was casting about in my head for the appropriate work to
call HX, process seemed most likely. <br clear="none">
</div>
<div>the point is that, as you point out, it modulates the bias, which
should then change the location of the trailing edge? What affect
does this have on the bias signal on the tape for John and Jaime
to process?</div>
<div>Cheers</div>
<div>Alan<br clear="none">
</div>
<div><br clear="none">
</div>
<div class="yiv5840493414yqt8503393163" id="yiv5840493414yqt90603">
<div class="yiv5840493414moz-cite-prefix">On 2/11/2020 11:03 AM, Bill Whitlock
wrote:<br clear="none">
</div>
<blockquote type="cite">
</blockquote></div>
</div>
<div class="yiv5840493414yqt8503393163" id="yiv5840493414yqt99507">
<div>
<div style="color:black;font:12pt Arial, Helvetica, sans-serif;">I'd
hesitate to call HX Pro a "process". All HX Pro does is to
account for the fact that HF program material tends to "bias"
itself and that this HF program content, when combined with
fixed ultrasonic bias results in significant self-erasure and
loss of HF MOL (maximum HF level residual on the tape). So HX
Pro simply modulates the ultrasonic bias so that the combined
effect of program HF bias plus ultrasonic bias remains
constant. Depending on tape and speed, it can improve HF
"headroom" or maximum HF audio output level by up to 6 or 8 dB.
It doesn't change frequency response of the record/play process
- except at levels where MOL/saturation is an issue. I guess it
technically is a "process" but it's record side only, no
"decoding" needed.
<div><br clear="none">
</div>
<div>Hope that made sense. Lots of folks actually believe(d)
that HX Pro was another noise reduction system. It's not of
course, it's simply a way to get the most out of a given tape
at high audio frequencies. Not so much an issue at 15 IPS, but
really a big deal at 1-7/8 IPS - where it can make ordinary
iron oxide tape perform like chrome.</div>
<div><br clear="none">
</div>
<div>Bill Whitlock<br clear="none">
<br clear="none">
<br clear="none">
<br clear="none">
<div style="font-family:arial, helvetica;font-size:10pt;color:black;">-----Original
Message-----<br clear="none">
From: Alan Garren via ProAudio <a rel="noopener noreferrer" shape="rect" class="yiv5840493414moz-txt-link-rfc2396E" ymailto="mailto:proaudio@bach.pgm.com" target="_blank" href="mailto:proaudio@bach.pgm.com"><proaudio@bach.pgm.com></a><br clear="none">
To: John Chester <a rel="noopener noreferrer" shape="rect" class="yiv5840493414moz-txt-link-rfc2396E" ymailto="mailto:jkc@jkc-lab.com" target="_blank" href="mailto:jkc@jkc-lab.com"><jkc@jkc-lab.com></a>; proaudio
<a rel="noopener noreferrer" shape="rect" class="yiv5840493414moz-txt-link-rfc2396E" ymailto="mailto:proaudio@bach.pgm.com" target="_blank" href="mailto:proaudio@bach.pgm.com"><proaudio@bach.pgm.com></a><br clear="none">
Sent: Tue, Feb 11, 2020 10:42 am<br clear="none">
Subject: [ProAudio] HX Pro was :FeralA - Recordings released
encoded with Dolby A<br clear="none">
<br clear="none">
<div dir="ltr">On 2/11/2020 10:12 AM, John Chester via
ProAudio wrote:<br clear="none">
> Why does perfect azimuth adjustment usually not
produce minimum <br clear="none">
> interchannel time difference? The most obvious
answer is gap scatter <br clear="none">
> in the record head, but there are others. Record EQ
may not be <br clear="none">
> precisely matched, and bias setting may be different.
Recording occurs <br clear="none">
> at a point slightly past the trailing edge of the
record head gap, and <br clear="none">
> that distance varies as bias level changes.<br clear="none">
<br clear="none">
<br clear="none">
This causes me to wonder if you have had to try this on an
HX processed <br clear="none">
tape. I am only aware of one pro deck with HX Pro, the
studer A820, and <br clear="none">
most people leave it turned off anyway. But it is there on
some later <br clear="none">
models. (possibly on the A827 as well, can't remember)<br clear="none">
<br clear="none">
Seems like a horror story for your process, chasing a HF
modulated bias <br clear="none">
level.<br clear="none">
<br clear="none">
<br clear="none">
Cheers<br clear="none">
<br clear="none">
Alan
<div class="yiv5840493414yqt1448531379" id="yiv5840493414yqtfd88679"><br clear="none">
<br clear="none">
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