Hey,

Does anyone know the max db full scale for both the DA78 and the MX
2424. I own an MX 2424 and use three da78's every day and I also use
the prism dream ada8 which run into two of my three DA78's at work.
The prism is set for plus 18 but the manuals on both the mx2424 and
the da78 do not list the max db full scale in there respective manuals
specification's. This is pretty strange. I would like to print this
specification on a sticker on the front panel as a reference for all
engineers using both machines. As far I can tell the level is plus 16
dbfs but I can't say exactly and would like to know for sure.

Thanks in advance.

Cameron

Cameron Wiley wrote:

Hey,

Does anyone know the max db full scale for both the DA78 and the MX
2424. I own an MX 2424 and use three da78's every day and I also use
the prism dream ada8 which run into two of my three DA78's at work.
The prism is set for plus 18 but the manuals on both the mx2424 and
the da78 do not list the max db full scale in there respective manuals
specification's. This is pretty strange. I would like to print this
specification on a sticker on the front panel as a reference for all
engineers using both machines. As far I can tell the level is plus 16
dbfs but I can't say exactly and would like to know for sure.

Thanks in advance.

Cameron

I believe you are asking your question somewhat backwards. Your Prism is
set for -18dbfs to equal 0vu or 1.228v, not "plus 18". The easiest way
to determine the reference level of your digital input would be to feed
it a 0vu (1.228v) tone out of an oscillator and see where it registers.

Eric
--
www.raw-tracks.com

Specifications on page 72 of the DA-78 manual says reference level is -16dB.

EricK wrote:
Cameron Wiley wrote:

Hey,

Does anyone know the max db full scale for both the DA78 and the MX
2424. I own an MX 2424 and use three da78's every day and I also use
the prism dream ada8 which run into two of my three DA78's at work.
The prism is set for plus 18 but the manuals on both the mx2424 and
the da78 do not list the max db full scale in there respective manuals
specification's. This is pretty strange. I would like to print this
specification on a sticker on the front panel as a reference for all
engineers using both machines. As far I can tell the level is plus 16
dbfs but I can't say exactly and would like to know for sure.

Thanks in advance.

Cameron


I believe you are asking your question somewhat backwards. Your Prism is
set for -18dbfs to equal 0vu or 1.228v, not "plus 18". The easiest way
to determine the reference level of your digital input would be to feed
it a 0vu (1.228v) tone out of an oscillator and see where it registers.

Eric

In article writes:

Does anyone know the max db full scale for both the DA78 and the MX
2424.

Since you used the term "dB full scale" that's easy to answer - 0.
Full scale is full scale.

I think what you want to know is what analog input voltage produces a
digital full scale level, and what analog voltage comes out when a
full scale signal is playhed back (which should be the same as the
input voltage). I think TASCAM equates +4 dBu to -16 dBFS (at least
they did on the +4 inputs of the DA-38 - the MX-2424 might be
different since it was designed by a different group), so the answer
there would be +20 dBu equals full scale digital.

Unfortunately there has been no industry standard established for the
relationship between analog and digital levels. By having a certain
amount of leeway, manufacturers can advertise better signal-to-noise
ratios that most users can't achieve, and that's a good thing when it
comes to products where marketing plays a big part in engineering.

Most of today's 24-bit gear runs pretty close to +4 dBu = -20 dBFS,
but it does vary. The concept of variable input sensitivity and output
level has gone by the wayside with digital equipment because they
don't want to stick another component that might make noise in line if
they can get away with it, so they leave it to the customer to make
his own interface adjustments or accommodations.

Damn shame. I'd be happy to put up with a -98 dBu noise floor instead
of -105 dBu if I could make all my meters line up, but the marketing
departments see this as a reason to buy the competiton.


--
I'm really Mike Rivers - )
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 he double-m-eleven-double-zero at yahoo

"Cameron Wiley" wrote in message
om...
Hey,

Does anyone know the max db full scale for both the DA78 and the MX
2424. I own an MX 2424 and use three da78's every day and I also use
the prism dream ada8 which run into two of my three DA78's at work.
The prism is set for plus 18 but the manuals on both the mx2424 and
the da78 do not list the max db full scale in there respective manuals
specification's. This is pretty strange. I would like to print this
specification on a sticker on the front panel as a reference for all
engineers using both machines. As far I can tell the level is plus 16
dbfs but I can't say exactly and would like to know for sure.

Thanks in advance.

Cameron

Is this a trick question? The max dBfs would be 0! g

"Mike Rivers" wrote in message
news:znr1080487034k@trad...
Unfortunately there has been no industry standard established for the
relationship between analog and digital levels. By having a certain
amount of leeway, manufacturers can advertise better signal-to-noise
ratios that most users can't achieve, and that's a good thing when it
comes to products where marketing plays a big part in engineering.

There very much IS an industry standard which is -18RMS or -20VU for average
signal levels.

There are just very few manufacturers willing to spend what it costs to meet
that standard without distortion so many hide behind claims of there not
being one.


--
Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!
615.385.8051 http://www.hyperback.com

In article writes:

There very much IS an industry standard which is -18RMS or -20VU for average
signal levels.

But what does that have to do with relating analog levels to a digital
scale? And what meter are you reading these on, or with what test
equipment?

If you're suggesting that a sine wave with an RMS amplitude of +4 dBu
gives a digital level of -18 dBFS, I'd believe that (but I'm not sure
whose standard it is). I don't know about the -20 VU point, though. A
standard VU meter doesn't have good enough resolution so that you can
read it very well at around -20.



--
I'm really Mike Rivers - )
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 he double-m-eleven-double-zero at yahoo

Romeo Rondeau wrote:
Is this a trick question? The max dBfs would be 0! g

He wants to know what analogue level will give him 0 dBFS coming out of
the output.

And to get that, you plug the signal generator into the input, you crank
the attenuator on the signal generator up, and when it hits 0 dBFS on
the meters, you read whatever the attenuator is set to.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Mike Rivers" wrote in message
news:znr1080506308k@trad...
But what does that have to do with relating analog levels to a digital
scale? And what meter are you reading these on, or with what test
equipment?

SMPTE/EBU and probably also an NAB standard. Average levels are supposed to
be 18 dB below full scale measured with an RMS meter or 20 dB below full
scale using a real VU meter because it responds differently from a true RMS.

Analog level is whatever you choose, generally +4 here in the US.

--
Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!
615.385.8051 http://www.hyperback.com

Bob Olhsson wrote:

SMPTE/EBU and probably also an NAB standard. Average levels are supposed to
be 18 dB below full scale measured with an RMS meter or 20 dB below full
scale using a real VU meter because it responds differently from a true RMS.

Analog level is whatever you choose, generally +4 here in the US.

Which, if you feed it to 95+% of the ADCs on the market will result in clipped peaks. Unfortunate, but true.

Since most facilities are almost all digital nowadays, I set the analog levels to maximize headroom and SNR for their ADC. If there is a decent amount of pro analog outboard ahead of this, I'll build attenuators to make the ADC conform to +4 nominal.

"Kurt Albershardt" wrote in message
...
Which, if you feed it to 95+% of the ADCs on the market will result in
clipped peaks. Unfortunate, but true.

Very true. Most recent gear shouldn't be run at +4.

--
Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!
615.385.8051 http://www.hyperback.com

In article writes:

SMPTE/EBU and probably also an NAB standard. Average levels are supposed to
be 18 dB below full scale measured with an RMS meter or 20 dB below full
scale using a real VU meter because it responds differently from a true RMS.

I'd have to re-read my article on levels and metering to get the right
numbers (at the time) but you're right that there's a SMPTE convention
for digital levels which jives with -18 dBFS. It's something like the
eyeball average level as displayed on a digital peak reading meter is
around -20, with no peaks higher than -10 dBFS. The Canadians are even
more conservative, wanting to keep most peaks at -20 dBFS. Apparently
they don't like to have to turn faders down when they have a lot of
channels going into a mix.

VU is different, though, and as far as I know, there is no digital
meter that has the same response as an analog VU meter (Dorrough has
something close) so you really can't relate digital level to VU other
than at the analog side.

Analog level is whatever you choose, generally +4 here in the US.

And I believe that was the question - what analog level produces what
digital level. The answer, as you've so concisely stated it, is
anything that you choose, with the proviso that the user is rarely
given a choice, other than occasionally the gross choice of -10 dBV or
+4 dBu reference levels. However, what they're referenced to (on the
digital side) with a few exceptions is decided by the manufacturer and
nailed into the A/D and D/A hardware.


--
I'm really Mike Rivers - )
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 he double-m-eleven-double-zero at yahoo

VU is different, though, and as far as I know, there is no digital
meter that has the same response as an analog VU meter (Dorrough has
something close) so you really can't relate digital level to VU other
than at the analog side.

The Dorrough Loudness indication is integrated over a period of 600 ms.
The VU meter has an integration time of 300 ms.
The PPM has an integration time of 10 ms with a slower decay time.
The AES/EBU Digital Peak meter has an attack-time of one sampling period.

Data fyi.
-- from "Hanbook for Sound Engineers" third ed. Edited by Glen Ballou.

Hey all,

Thanks for the replies. I did finally see the reference level printed
on page 72 of the DA 78 manual. Sorry! I am becoming more and more
blind. But I do think that tascam has changed their reference
specification. I am almost sure it used to be a + number though I
can't find my old DA88 manual right now to confirm.

The prism manual is also a positive number. The manual actually
states "analogue I/O line up at 0dBFS = +18dBu ". This is actually
configurable on a screen on the prism that says "Set dBu=0dBFS". Our
currently reads +18.0dBU where we set it. It is being fed by grace
801R which easily have the headroom to feed these with plenty of
headroom. I unfortunately don't have a reliable stable tone generator
except from my DA7 or O2R and no working oscilloscope. There does
seem to be an approximately 2dB difference between the level reading
on the Prism and level on the DA78.

Cameron



(Scott Dorsey) wrote in message ...
Romeo Rondeau wrote:
Is this a trick question? The max dBfs would be 0! g

He wants to know what analogue level will give him 0 dBFS coming out of
the output.

And to get that, you plug the signal generator into the input, you crank
the attenuator on the signal generator up, and when it hits 0 dBFS on
the meters, you read whatever the attenuator is set to.
--scott

In article writes:

The Dorrough Loudness indication is integrated over a period of 600 ms.
The VU meter has an integration time of 300 ms.
The PPM has an integration time of 10 ms with a slower decay time.
The AES/EBU Digital Peak meter has an attack-time of one sampling period.

So what's the answer? 43?

--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

In article znr1080678221k@trad, Mike Rivers wrote:
In article writes:

The Dorrough Loudness indication is integrated over a period of 600 ms.
The VU meter has an integration time of 300 ms.
The PPM has an integration time of 10 ms with a slower decay time.
The AES/EBU Digital Peak meter has an attack-time of one sampling period.

So what's the answer? 43?

The answer is from RTW, and it can be set to a dozen different
ballistics, including some wacky ones from Scandinavian broadcasting
centers that I have never heard of.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article writes:

Thanks for the replies. I did finally see the reference level printed
on page 72 of the DA 78 manual. Sorry! I am becoming more and more
blind. But I do think that tascam has changed their reference
specification. I am almost sure it used to be a + number though I
can't find my old DA88 manual right now to confirm.

They may have changed it, but not from a negative number to a positive
number. However, what you're thinking about may be that they just
express the same thing (or nearly the same thing) differently.

The positive number is +4. This is the analog level (+4 dBu) that
produces the digital level that they want to be nominal, leaving
what's left as headroom. That digital level is around -18 dBFS, which
is your "negative number."

The prism manual is also a positive number. The manual actually
states "analogue I/O line up at 0dBFS = +18dBu ".

That means that +18 dBu going in, will send the meters to full scale.
So what will the meters read with an analog level of +4 dBu going in?
14 dB lower, or -14 dBFS.

By the way, this is kind of sensitive by today's standards but, as Bob
O points out, is a good choice when fed from analog equipment that
can't provide 20 dB of headroom over a nominal level of +4 dBu without
distorting.


--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

Scott Dorsey wrote:

Mike Rivers wrote:
writes:

The Dorrough Loudness indication is integrated over a period of 600 ms.
The VU meter has an integration time of 300 ms.
The PPM has an integration time of 10 ms with a slower decay time.
The AES/EBU Digital Peak meter has an attack-time of one sampling period.

So what's the answer? 43?

The answer is from RTW, and it can be set to a dozen different
ballistics, including some wacky ones from Scandinavian broadcasting
centers that I have never heard of.

Like 420.

--
ha