Pro Tools outs clipping A&H Line ins?

Archived from groups: rec.audio.pro (More info?)

We just swapped our Mackie 24 8 bus for a new Allen & Heath MixWizard3
board. Trouble is the main outs (1/4" balanced) from our Digi 002R are
clipping the line ins on the board even with the trims all the way
down... When PFL'd the A&H meters show between +9 and +16. It's only
a problem with hot material (full mix with an L2 on the master fader),
but it is definitely audible on louder passages. Very annoying!

This was never a problem with the Mackie (granted we were using tape
returns there.) This board sounds better, has better EQ, and fits our
needs size wise so i'm really hoping this is solveable. Any help is
greatly appreciated.
Thanks,

Dan Fox
ZUMIX, Inc

Archived from groups: rec.audio.pro (More info?)

In article <1122870166.798439.231050@g47g2000cwa.googlegroups.com> upryz1@gmail.com writes:

> We just swapped our Mackie 24 8 bus for a new Allen & Heath MixWizard3
> board. Trouble is the main outs (1/4" balanced) from our Digi 002R are
> clipping the line ins on the board even with the trims all the way
> down... When PFL'd the A&H meters show between +9 and +16.

This is a common digital-to-analog interface complaint. It's converse
is the complaint on the input side of "I can't get a hot recording
from my mixer." Digital outputs pack a lot of wallop at full scale,
and they require a mighty high input voltage to reach full scale.

Does the 002R have an output level selector switch (probably in
software) that you can use to set the output level to nominal
-10 dBV? If so, set it for that and your problems will go away.

> This was never a problem with the Mackie

Mackie's input trims go down further, so you can attenuate the input
signal to an acceptable level. Enjoy the improved sound of your A&H
and adapt it as necessary.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

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Where do I get these? And will they have any effect on the signal
other than attenuating it?
I'm almost positive the 002R does not have an output level control
(hardware or software) but i'll double check.

Dan Fox

Archived from groups: rec.audio.pro (More info?)

The converters' calibration is not adjustable on the 002 line of
products. For reference, -14 dBfs = +4 dBu. This particular spec
isn't atypical these days, and as long as you observe nominal levels
when tracking (same calibration at the A to D), really ought not to
give you problems with modern mixers.

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Daniel Fox <upryz1@gmail.com> wrote:
>
>The only Shure pad that I've found is the A15AS with XLR ins and outs
>for $35!!
>Thats near $300 bucks just for pads for all 8 Pro Tools outputs! Plus
>the cabling from the patchbay (TRS) and from the pad to the line in
>(TRS). This has got me steamed!

That seems about a reasonable price. If you want, you can make your own,
but the barrel connectors will cost almost that much.

These days, with the bargain basement equipment available today, it is
not surprising to see cabling, connectors, and miscellaneous interface
things like transformer boxes and pads costing as much as the equipment.

>These are pretty standard pieces of gear (002R and MixWizard3) and I
>just can't believe that neither Allen & Heath nor Digidesign has made
>any provisions for such a typical setup.
>
>I am willing to build some simple pads if someone was so kind as to
>have a schematic and parts list.

You can build cables with pads. Try 6 dB to start with. Schematic is
in the Audio Cyclopedia under "T-pads."

>Otherwise we may have to return the A & H and put the Mackie back in
>place (I just shed a single tear).

You'll just be down this road again somewhere else with some other gear.
Get a big bag of pads and a big bag of isolation transformers and you'll
be fine. You will always need them for something.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Right. A&H actually told me +27. A typical modern recording
especially pop/rock/hiphop/etc (whether my mix or commercial) hovers
around +12 on the A%H meter with the red light at the top of the ladder
flickering every once in a while. This does not indicate +27... But I
swear I hear some distortion in the high mids that goes away when I
pull down the master fader in pro tools 6 db or so.
I'm think i'm going to learn a lesson in building an 8 in 8 out trs to
trs pad box. grumble grumble...

Dan

Archived from groups: rec.audio.pro (More info?)

"Daniel Fox" <upryz1@gmail.com> wrote in message
news:1122938351.822647.90970@g14g2000cwa.googlegroups.com
> Chris Cavell wrote:
> This particular spec
>> isn't atypical these days, and as long as you observe
>> nominal levels when tracking (same calibration at the A
>> to D), really ought not to give you problems with modern
>> mixers.
>
> Well... it is and i'm not doing anything atypical. Even
> if I play commercial songs through ITunes (using
> digidesign core audio manager) I have the same problem.
>
> The only Shure pad that I've found is the A15AS with XLR
> ins and outs for $35!!

The Proco fixed pads are about $20.

http://www.sweetwater.com/store/ma [...] Pro_Co/pn8

see MAX10, MAX20, etc.

You can make your own for as little as $10. First buy the
classic Switchcraft S3FM male-female XLR shell

http://www.sandlpro.com/ItemView.cfm?INV_ID=3989

or some Hosa polarity inverters

http://www.sweetwater.com/store/detail/GXX195/

Then dissassemble and rewire as attenuators per this web
page:

http://www.uneeda-audio.com/pads/

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In article <1122956474.957676.132770@f14g2000cwb.googlegroups.com> upryz1@gmail.com writes:

> ... But I
> swear I hear some distortion in the high mids that goes away when I
> pull down the master fader in pro tools 6 db or so.

Are you sure you're not clipping your mointor amplifier? You need a
voltmeter and maybe an oscilloscope to see where your clipping is
occurring. Or just drop the levels down so that the meters are working
around 0 VU and not all the way at the top of the scale.




--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

Will,
Are you reading the MixWizard3 (newest model) specs. I believe that
the balanced line ins from the factory are +4.

Dan

Archived from groups: rec.audio.pro (More info?)

To generate more headroom at the mix buss on the board...i think that's
what they claim in the manual anyway...it's nothing new; mackie's been
doing the same thing for years.

However, that 1k tone should be set at -14dBfs to give you a 0VU
reading on your board.

Archived from groups: rec.audio.pro (More info?)

"WillStG" <willstg@aol.com> wrote:
>
> [...] you might want to compare the sound of mutiple tracks with pads
> engaged compared to multiple tracks with their individual output
> faders just pulled down 6-7DB across the board.



I recently had to cut together a bunch of stuff that had been imported
from "all the way up" sources (peaks at 0dBFS). I just pulled down the
faders in Pro Tools when transferring it out to other devices in the
plant.

Even when you can't control the level on the way in, controlling it on
the way out is easy.

--
"It CAN'T be too loud... some of the red lights aren't even on yet!"
- Lorin David Schultz
in the control room
making even bad news sound good

(Remove spamblock to reply)

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In article <1123035311.497470.286970@g49g2000cwa.googlegroups.com> upryz1@gmail.com writes:

> I ran a test today sending a 1khz test tone (-6 db) out of all 8 digi
> outputs to the board. When PFL'd the meters showed +3 db.

> For what reason would the PFL meters
> read 3 db higher than the same signal at unity gain?

Different concept of what "zero" is. The official way of defining the
analog level for 0 dBFS is the RMS value of a sine wave that peaks at
full scale. An alternate (and equally common) way of defining it is
the peak value of the sine wave that peaks at 0 dBFS. There's 3 dB
difference between those two analog voltages.

Nobody openly says which calibration method they use.

I'm not sure I understand the relationship between the -6 dB tone (is
this a computer-generated tone at that level? ) and the +3 dB reading
on the console meters.

If the console is set for unity gain, the -6 dB tone should read
6 dB below whatever the full scale output of the Digidesign interface
is, relative to whatever the 0 VU sensitivity of the console is. This
is what you should see on the meter when you press the PFL button on
an input channel. For instance, if full scale output of the 002 is, as
someone suggested, +18 dBu, and if the console is calibrated so that
0 VU = +4 dBu (this usually means that the gain trim is at its unity
position), the -6 dBFS tone should produce an output of +12 dBu from
the 002, so the PFL meter should read +8 VU (that's not dBu).



--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

Is it possible to be overdriving the virtual bus within Pro Tools even
if no clip lights are lit anywhere?

Archived from groups: rec.audio.pro (More info?)

Chris Cavell wrote:
> Daniel, yes...in a way...
>
> The master fader is different than other tracks in that the plugins are
> post fader, but the meter is post plugins. You could be clipping the
> buss (disable all plugins on the master fader and lower the fader until
> it doesn't light up the clip light). Or you could be clipping a
> plugin...and that often won't show up anywhere but in the plugin itself
> depending upong your chain.

No you got me thinking. Worst case scenario (and I certainly try not
to let this happen): with no plug ins on the master fader (set at
unity) the sum of all tracks is clipping the master fader. I then
insert a waves L2 limiter on the master fader. The L2 it self will not
clip because it incorporates a "ceiling" (which I usually set at -.2).
The resulting master fader meter does not show clipping, but levels
near the top. My understanding was that the L2 took the overly hot sum
of all channels and limited it so as to keep it under the "ceiling".
Are you saying that in this case I could be inducing digital distortion
even though none of the meters indicate this?

Dan

Archived from groups: rec.audio.pro (More info?)

Jeez, That's the problem! All this time i've been using carpentry
tools to work on music. What was I thinking? But seriously, your
point is noted however, when I use a L2 it is usually only doing 1-3
db of GR.

Dan

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Daniel Fox <upryz1@gmail.com> wrote:
>Jeez, That's the problem! All this time i've been using carpentry
>tools to work on music. What was I thinking? But seriously, your
>point is noted however, when I use a L2 it is usually only doing 1-3
>db of GR.

Then you might be able to get away with even more of it. Just keep
listening and crank the levels into the L2 up until you hear it starting
to sound funny. Then drop them back down.

You shouldn't be hearing dramatic tonal changes in the L2, other than
maybe a little softening on the top end. If you are hearing it, you
are hitting it too hard.

If you have to hit it that hard to get your levels right, you probably
aren't compressing properly before you hit the L2. If, on the other
hand, the top end is still screwed up even with the L2 bypassed and
levels down, you're probably compressing too much beforehand. Or at
least too fast.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."