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Digi 192 Calibration levels? DAW Software
Old 11th November 2005
  #1
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Digi 192 Calibration levels?

I just got a Digidesign 192. I was doing a comparison of the converters between the HD192 and my Cranesong HEdd-192. The cranesong input from AD was much louder then the Digi 192. I turned up the trim in the back of the Digi 192. I can't get it as loud as the Hedd-192. I took a test tone and tried to match the two to get a accurate level. First off how do you get a accurat level in protools. I brought up a waves metter but it shos the level around -16db. It is hard to tell exaclty. I need to see a number. Is there a reason why the Hedd level is hotter?
please help
thanks
Old 11th November 2005
  #2
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C.Lambrechts's Avatar
 

Quote:
Originally Posted by passionmax
I just got a Digidesign 192. I was doing a comparison of the converters between the HD192 and my Cranesong HEdd-192. The cranesong input from AD was much louder then the Digi 192. I turned up the trim in the back of the Digi 192. I can't get it as loud as the Hedd-192. I took a test tone and tried to match the two to get a accurate level. First off how do you get a accurat level in protools. I brought up a waves metter but it shos the level around -16db. It is hard to tell exaclty. I need to see a number. Is there a reason why the Hedd level is hotter?
please help
thanks
The Hedd is factory calibrated with 12 dB of headroom. The 192 with 18 dB of headroom.

You cannot adjust the headroom of the hedd (I think) an d the factory 192's will allow you to calibrate up to -14 dB.

accurate level in PT : go into calibration mode .... accurate within .1 dB
Old 11th November 2005
  #3
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I believe there are gain trims on the rear of the HEDD (and of courseon the back of the 192).
Old 12th November 2005
  #4
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minister's Avatar
Quote:
Originally Posted by passionmax
I just got a Digidesign 192. I was doing a comparison of the converters between the HD192 and my Cranesong HEdd-192. The cranesong input from AD was much louder then the Digi 192. I turned up the trim in the back of the Digi 192. I can't get it as loud as the Hedd-192. I took a test tone and tried to match the two to get a accurate level. First off how do you get a accurat level in protools. I brought up a waves metter but it shos the level around -16db. It is hard to tell exaclty. I need to see a number. Is there a reason why the Hedd level is hotter?
best way:

buy a multi meter with enough resolution to read 1.228v. for post (in the U.S.)-20dBFS for recording music -18dBFS = 0 VU (or +4 dBU, or 1.228V)

then roll up your sleeves.

create a new session, whatever bit depth SR you want. select either your A or B trims in the HW dialogue.

new mono aux track, input set to none. assign output to mono out 1. put a signal genny plug-in on the track. set the Genny to -18dB at 1kHz. keep aux track's at fader at unity (0dB).

create as many mono aux tracks as you have analog outputs. assign the input of all these aux tracks to bus 1. cascade the outputs of all these auxes to your outputs starting at output 1 and ending at output X ***IMPORTANT: make sure to use mono outputs not stereo outputs***. Put those faders at unity (0dB).

Using your TRUE RMS voltmeter measure the AC voltage at output 1 -- adjust the A or B potentiometer for 1.228v on each output.

192's are NOTORIOUSLY mis-calibrated form the factory. in fact, high school, they were voted "miss-calibrated"

then you KNOW that it is right ANLOLOG wise.

the A trims are for one set of cal's the B trims are for another set. say you do music AND post. A= -18dBFS B= -20 dBFS.
Old 12th November 2005
  #5
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Actaully what I ended up doin before I read your email was the following.
For out put. I played back the test tone at -18db. then routed it back into the 192 to see the level. When it came back in the outputs were set to -14.9. I tried to set the input to -18 sot he outs matched the ins. It only let me go down to -17.9db. i ended up triming them until it said-16db which matched zero on avalon 747 analog.

let me know if this is correct. The inputs are calibrated to -18db
and now the outputs are calibrated to -16db.
Old 12th November 2005
  #6
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minister's Avatar
well........

how dead on do you want to be?

problem is, you don't know what the output voltage is on the 192 analog out...and your way doesn't tell you that, sorry to say.

and, did you use a mono track with a stereo output? if you did, then your level is not correct.
Old 12th November 2005
  #7
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Fair warning. Using -18dBFS means you're gonna have to push your analog gear to the limits if you print hot levels. You cant jsut print really low levels, but if someone sends you material that was recorded hot, then -18 is going to pin the inputs to your mixing console (if you have one). I have found that -14 (since the digi interfaces can't do -12) is a happy medium where I can print higher levels without worry about the console inputs getting slammed, or the analog chains going to the interfaces aren't being pushed too hard.

The other school of thought again, is to just print lower, but for me why waste the bits just for the sake of using a really low calibration level that was really meant for post work.
Old 12th November 2005
  #8
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minister's Avatar
Quote:
Originally Posted by jonnyclueless
Fair warning. Using -18dBFS means you're gonna have to push your analog gear to the limits if you print hot levels.
??

good audio practice = DON'T PRINT HOT LEVELS INTO YOUR DAW!

this is the correct way to calibrate. you really should be calibrating -18dBFS = O VU. and you should be recording, on average -18dBFS levels into your DAW. because, yes, otherwise you are overdriving your analog gear. anaologue gear like 0VU. with 24 bit, the -18 signal is still fantastic. make up for the level later with faders or make up gain.
Old 12th November 2005
  #9
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Quote:
Originally Posted by minister
??

good audio practice = DON'T PRINT HOT LEVELS INTO YOUR DAW!

this is the correct way to calibrate. you really should be calibrating -18dBFS = O VU. and you should be recording, on average -18dBFS levels into your DAW. because, yes, otherwise you are overdriving your analog gear. anaologue gear like 0VU. with 24 bit, the -18 signal is still fantastic. make up for the level later with faders or make up gain.
That's absolutely untrue. You are only overdriving your analog gear because you are choosing to use a low calibration level. With the proper calibration level this is not an issue. Even the converter manufacturers such as Apogee say the converters run most opimally at -12dBFS.

And your idea ONLY works if you are the only one involved in your project. I have yet to ever get a project where the average signal lies around -18dBFS, thus using -18dBFS means that the input to my console would pretty much always be clipping. If you don't use -18dBFS like most people do, then you don't have to worry about any of these issues.

so with all due respect, good audio advice is "DONT PRINT HOT IN YOUR DAW ONLY IF YOU CHOOSE TO CALIBRATE TO -18"

;-)
Old 12th November 2005
  #10
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minister's Avatar
hey johnny,

it does get hard when multiple studios work on projects. and many studios do not calibrate.

(mostly, i was talking about slamming levels up to -2dBFS and -1 on recording.)

curious, do you use your A & B trims?

and i am confused about something. if i record something cal'd to -18dBFS=0VU and my levels average around -18 -- you know, 24dBFS --> -12dBFS, let's say, and i send it to you and you are cal'd to -14dBFS=0VU. how would my levels clip your console inputs? wouldn't they be lower? yours would be averaging -14, mine 4 dB less.
Old 12th November 2005
  #11
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Quote:
Originally Posted by minister
hey johnny,

it does get hard when multiple studios work on projects. and many studios do not calibrate.

(mostly, i was talking about slamming levels up to -2dBFS and -1 on recording.)

curious, do you use your A & B trims?

and i am confused about something. if i record something cal'd to -18dBFS=0VU and my levels average around -18 -- you know, 24dBFS --> -12dBFS, let's say, and i send it to you and you are cal'd to -14dBFS=0VU. how would my levels clip your console inputs? wouldn't they be lower? yours would be averaging -14, mine 4 dB less.
Hiya! :-)

I have A set to -14dBFS and B set to -18dBFS so I can switch between the two dpending on the levels. Where the confusion lies is that the lower the cal level, the hotter the output level will be. If I was set to -14dBFS in the scenario you describe, then the level of course wouldn't clip the console. But if I was at -18 it would have a more likely chance to. And this being a scenario where the levels are preinted very low, something I almost never come across.

Then there is the reasoning that the levels should be low because you don't want to strain the analog gear. But again, the only reason you would strain your analog gear with hotter levels is because the calibration level is so low. With a higher calibration level this becomes a non issue as it doesn't take as much output from the analog gear intro the DAW and the output of the DAW is lower.

Unfortunately the majority of tuff I get is by bad engineers who print everything right up to zero. Even at -14dBFS this can often clip the console inputs. Not to mention that when it comes to bouncing down 8 tracks of backround vocals all printed right up to 0 the result is a distroted signal.

But I think the biggest reason for this issue is that most DAWs don't have ny accurate way of keeping track of the level. The mters are generall two small to have an kind of level indicators so people just try to get the peaks close to 0 because there is no real visual reference. What they should do is make a user setable marker on faders so you can have an indicator at the level you reference to.
Old 12th November 2005
  #12
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minister's Avatar
right.

also, if i am cal'd to -18 and i run my signal just up to 0, then i got drive my mic-pre harder to get there. across a mix, that harmonic distortion from the analog side adds up, and doesn't always sound pleasant. with the advent of DAW's bad practice became easy.

and you are right some of it has to do with very poor metering in the DAW. PT's meters are almost worthless. the new Inspector XL meters are not bad and include the K-sytem - K-20, K-14 & K-12, which i use on LE rig, or sometimes just the RMS or Peak metering.

and part of it is many don't understand what happens to their analog chain with those hot levels.

the other issue with hot levels, is when you modulate your digits to 0dBr (sample value) your signal into the plug-ins are difficult to reconstruct properly. plug-ins don't like HOT inputs either. and many times, those inserts we use are pre-fader.

there are so many reasons not to print overly hot levels. calibrate your system and your room right, and this all makes sense. then you can crank up he levels at the end and it is so much more open and less distorted and loud than if you slam from the beginning to end.
Old 13th November 2005
  #13
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Calibration of Digi 192 with HEDD 192

First of all: jonny-not-so-clueless is absolutely right!
When you calibrate your PT rig to -20dBFS you're very likely to overload the console even more these days where people tend to record as close as possible to 0dBFS (don't do this, you're not gaining ANYTHING by doing this). I've got my PT rig also calibrated to -14dBFS, and still, I get projects in where I need to turn down the console's line inputs by a few dB. I've got the B trims set to -18, just in case...but I've never used them.
Other than that, I have the assistant check out calibration on other frequencies as well. Our procedure is: 50 Hz, 100 Hz, 1 kHz, 5 kHz and 10 kHz. I've only had it once where everything was fine at 1k, but there was a significant loss at 50 Hz and 100 Hz.

Quote:
Originally Posted by passionmax
I just got a Digidesign 192. I was doing a comparison of the converters between the HD192 and my Cranesong HEdd-192. The cranesong input from AD was much louder then the Digi 192. I turned up the trim in the back of the Digi 192. I can't get it as loud as the Hedd-192. I took a test tone and tried to match the two to get a accurate level. First off how do you get a accurat level in protools. I brought up a waves metter but it shos the level around -16db. It is hard to tell exaclty. I need to see a number. Is there a reason why the Hedd level is hotter?
please help
thanks
Passionmax,
Why don't you just take the easy way out? Calibrate both PT192 and HEDD 192 to -14dBFS. Yes you can calibrate the HEDD as well. It's got four trim pots on the back.
The PT192 will not go to the HEDD's -12, and the HEDD will not go to the 192's -18dBFS.
So, start by setting up a calibration template in Pro Tools. Set the tone generator to a 1kHz tone at -14dBFS. Distribute it to all outputs (through aux busses) and calibrate the outputs to read 0 dBm or 1.227 V AC. For that matter it is good to have a multimeter that reads dBm as well.
Calibrating to your Avalon 747 is okay as long as that one is calibrated as well. But if you want to be more accurate, go with a good digital multimeter.
Now do the same thing by sending the tone to your HEDD outputs. Probabely you'll send the tone to digital outs 1/2 and then go digital to the HEDD. Make sure you turn off all the HEDD processing (tape, triode, pentode). Now adjust you HEDD trims to read 0dBm.
There you go...You've successfully calibrated the outputs of both units.
Do the same thing for the inputs. First the PT inputs, by patching the PT outputs directly to the inputs. To adjust the input trims you'll want to set PT in calibration mode. Now invite a friend over who owes you one, and make him read the values in PT out loud while you, choking and puffing to reach for the cal pots behind your racks, trim the inputs. Take a break every two hours. heh
After having done that, you'll do the same thing with the HEDD.
You're done!!
Old 13th November 2005
  #14
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fwiw ... FACTORY 192's cannot go to -12. You can have your 192 modified by digidesign to have -12 dB of headroom or you can simply order them like that.

It's an 'on demand' thingy that CAN be done.
Old 13th November 2005
  #15
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minister's Avatar
Quote:
Originally Posted by The Alamo
First of all: jonny-not-so-clueless is absolutely right!
well...i wouldn't say absolutely...

to do audio post in the US, you need to cal to -20=0 VU and you actually do send tone when you print tapes (which is rare) and use a one frame -20dBFS beep for a sync. point. in europe (and elsewhere) they use -18. not only that, i count on using that dynamic range for my film mixes (and only 10dB for my TV mixes) so, for me, this is correct for this situation.

also, i interface with some pro recording studios who cal to -18, and don't record channels at close to zero. and , yes, they use a board with VU's. so -18 is right in this situation.

i think some radio production people use -14.

-14 is right for you and johnny clueless and many others. but not absolutely.

as i have read people say, standards are great because there are so many of them
Old 13th November 2005
  #16
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Quote:
Originally Posted by minister
well...i wouldn't say absolutely...
Minister, I meant he was right about the procedure, not just the numbers.
-18dBFS or -20dBFS would work for me too...-14dBFS is just easier to work with when sending all outputs to an analog console. And, I don't have the restrictions you were mentioning for audio post.
Now, for Passionmax, there aren't that many options if he wants both PT192 and HEDD calibrated the same: it's either -14, -15 or -16dBFS.

All The Best,
Old 21st September 2018
  #17
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zak7's Avatar
 

in a way all is BS, because if you worry about your console to overdrive, just lower the track in your DAW! and CHECK the VU in your console or analog gear!

now the reality is that u are concern about the RETURN of the mix in your DAW and yes, would be in a range of -20dbf -12dbfs of whatever u have your HEDD calibrated... also if you calibrate your HEDD at 12dbfs : 0VU ur tracks in your DAW will be at lower level in the fader and is also less resolution ...it really depends how u want it...and are different scenarios like a Summing box vs a Console...where in a console u do not necessarily need to have ur tracks in your DAW at unity level (0) ...u can always try to put the faders/level to avoid overdriving ur console....
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