"David Morgan (MAMS)" wrote:
I need some serious help here....
Hmmm ... do you realize how interesting that talk radio in the
background is?
Regulars probably know something about how my reluctance to dive
into all digital HD recording has impeded my experience level.
cough-cough
I don't read you closely enough then, please accept my apology, but I
was not optimally prepared for someone to post something about audio.
Being recently forced to mix a project in an all digi environment
with no house engineer and a number of stumbling blocks to overcome,
Allow me to put forth that the client should perhaps not pay for product
development and design, but rather for the service ordered and hopefully
rendered.
I am inclined to re-evaluate what was done there and I could
use some advice before making any recommendations to the client
- who has already blown the vast majority of his budget and needs
product in his hands for summer sales.
David, I don't know all about the exact wording of your deal with the
client, but redoing things may not be fairly billable.
I have posted two, one minute(+) clips of a song on my web site
to provide you a comparison test from which I would appreciate
your input. (Links below).
First a bit of typing while I listen.
I won't take the time to re-hash the entire experience unless
asked,
I'm ignorant enough to not be able to fairly comment on all detail.
but it has come to my attention that the resulting mixes all
suffer from a serious loss of upper mid & lower high frequency
content, as well as a mushiness to the low end, and that this
may have been caused by clocking or other sync oriented issues.
Whatever it is, it is a "you're dead", as grave as when I was unable to
deliver a CD on time to catch the trumpet player prior to his plane
leaving because of a compatibility issue between my Sony 2000 and my DiO
2448 leading to strange distortion.
The original source material was recorded at home by the client
on ADAT at 16bit, 44.1K. Before arriving in Montana, the studio
which the client had chosen to use agreed to dump the tracks onto
an Alesis HD-24 prior to the mix dates.
When we arrived there, the tracks had been dumped at 16 / 48k.
Strange choice to go for two times sample rate conversion, assuming the
end product is 44.1 anyway. I occasionally record on 48-16 because the
treble is better at the cost of a loss of spatial detail in sample rate
conversion, but such a trade-off does not seem to apply here.
The tools used were a Sony DMX-r100 (clock source), the HD-24
controlled by an Alesis BRC, and an Alesis Masterlink.
In the path before the Masterlink was a TC Finalizer. These
were all digitally integrated.
I know the sound of a couple of Finalizer models, they dull the sound
ever so slightly, almost only audible as a loss of background spatial
detail, not really obvious on foreground audio, even in bypass mode.
After being handed the manuals and wished "good luck" by the
studio owner, at the end of the first day the machines were
finally talking to one another.
It would be incompetent to try to comment on this.
The DMX-r100 had to be completely reconfigured from a rec/mix
session some two months earlier. The Finalizer could not be
removed from the chain by order of the owner, and the Masterlink
had no GUI peripherals. The Finalizer was supposedly set up
only for limiting to avoid clipping of the Masterlink and
nothing else...
Yeees, but what kind of limiting? - it is a very capable thingie, could
it have been set to produce something that fits say FM preemphasis no
matter how much treble is thrown at it? - I haven't checked the
difference between the files with any exactness, but it appears to be
something like a first order roll-off at 7.5 kHz.
I took his word for that and tried to stay out of soft limiting
while mixing.
Hmm ... you might have been better off doing what the setup was designed
to handle: pushing it mindlessly. But please Dave, I'm guessing.
The BRC had to be pitched down to control the HD-24 at 44.1K.
? - I don't understand this, the studio took it to 48 kHz, surely you
would then stay there until the mastering stage, downsampling again
should in my religious belief be the very last stage.
The desk was reset to send clock at that frequency as well,
and so *finally* after reconfiguring the routing as well,
the audio cleared up and was free of the
obvious timing errors and the mix ensued.
There is too much I don't know to grasp the details of the setup.
Please note that monitoring through the desk during mixdown
and during playback from the Masterlink, did *NOT* reveal
the severe degradation of the audio that was actually
taking place.
Severe and irrecoverable.
I cannot explain the resulting loss of frequency content.
Low pass filtering, possibly dynamic.
I took my own monitors and phones and three of us were involved
in the mix. None of the resulting symptoms became noticeable
until we had left the building with the final mixes.
Yes, yes, yes. I have once upon a time clipped an entire recording
session in the belief that it was the headphone amp in the A77 that
clipped. It wasn't, it was the effect of a capable mezzo into a pair of
borrowed small Neumanns on the Revox micpre. One does not hear what one
is not prepared for hearing. One does occasionally hear what one wants
to hear. Those who have fixed something by changing the settings on
device that is bypassed may raise their hands now.
The degradation was not discernable, even on play-back while
on this equipment.
I trust you nevertheless.
We were able to leave with only a DAT backup of the unedited
Masterlink files and an audio CD created by the Masterlink.
(The Masterlink was not set up with a monitor and essentially
was just a box in the rack).
I'm not totally sure what a Masterlink is. One thing I am wondering
about is whether audio went analog into the Masterlink, vague
remembering it to be a recorder of some kind.
Now that we are listening to the mixes and realizing how
dramatically different they are from the studio, I have to
make a recommendation of some sort to the client.
Redo. I can't see the cost of that being the clients problem, I'm sorry
to say it, but I really can't.
My first thoughts (other than shock and humiliation) were
that the product could be repaired in mastering, cleaning
up the mushy bass and adding some 1.6 to 3Khz or so for
clarity. There are 13 songs which all suffer
exactly the same symptoms.
The audio is broken beyond repair.
After requesting the original ADATs and re-mixing one song
here at home, I think there may have been serious problems
with the interfacing and likely my operation of the gear.
It is not really possible to know afterwards what went wrong.
Digital is not simple, not all boxes are alse "just a wire". Here is a
tale about that:
Being lazy and to keep the number of hours on my SV3800 down I have set
my Sony up as playback and transfer machine for getting sp-dif into my
daw. I recently recorder an anniversary CD for a guitar and mandolin
band.
It was recorded in two sessions, one in late november and one in
february. I had made a complete version of the 8 pieces of music from
the first session and made careful notes of just what I had done, and it
was approved by the conductor.
Back home with the 8 remaining pieces of music I transfered them to the
DAW via the Sony. There was no way they were ever in my opinion going to
pass as from the same session, they were different, and had a slightly
warmer sound with a bit less treble.
The sound was OK, nothing wrong with it per se and certainly not
something instantly measurable as this here problem you have is, but it
just didn't sound like the tracks from the first session. I made a new
sp-dif transfer from the SV3800 and it was as seamless as it ought to
be.
I'd appreciate any input from folks with experience in these
matters, as could pertain to this frequency loss which was
invisible in the studio.
An unproven and unprovable theory is that the Finalizer may have been
configured to do frequency dependent limiting, it think such
contraptions can do that too. The difference is as the difference
between a compact cassette and 38 cm/s half track tape.
Please keep in mind that in the re-mix, I made no attempt to add clarity in
any shape, form or fashion. I tried to use the same cut-only EQ schemes
and cut considerably more high end than I did in the all digi studio.
Which is to say that the problem was obvious over the monitors when you
mixed, but you just didn't hear it prior to the problem happening.
What you know is: you have a 44.1 multitrack recording that has the
treble and you have a mixdown of a version of it that was converted to
48 kHz and lacks the treble.
Things do not go that bad in the digital world, but some people seem to
assume that going from digital to analog and back is the proper way to
do sample rate conversion. The deterioration is on the order of
magnitude of not optimally good analog. You have not noticed it in the
studio because you did not compare the original tracks with the
converted tracks. No matter what, no matter how, that sample rate
conversion had no good reason graspable to me to at all get done. It is
the first place things can have gone wrong, and if they went wrong there
then it is explained why you didn't notice it in the studio.
Sample 1 - the original all digi mix....
MPEG-1 Layer 3, 44100 Hz, Stereo, CBR 256 kbps
http://www.m-a-m-s.com/WESTERN_LAND_I_LOVE-Test.mp3
Sample 2 - the analogue remix....
MPEG-1 Layer 3, 44100 Hz, Stereo, CBR 256 kbps
http://www.m-a-m-s.com/WESTERN_LAND_...REMIX-Test.mp3
What could have gone wrong here?? Recommendations? Things to avoid
or look out for in the future?
These constitute opinions:
The shortest route between two "boxes" remains a cable directly between
them.
Verify a digital transfer as you would an analog.
Remix at home at no cost to the client and apologize for the delay it
causes, you at least know what to aim for, just better.
Going back to the restaurant that served an inedible meal does not make
sense, the issue of a full or partial refund to cover your cost (loss of
other revenue) while redoing it is a different issue.
The disclaimer: I'm somewhat ignorant about these things, so I just
applied some common sense viewpoints, the main one being that the client
shouldn't pay twice to receive one mixdown.
David Morgan (MAMS)
Kind regards
Peter Larsen
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