Alignment question - meter calibration

Blue Jinn

Rider of the ARPocalypse
It's late so I may be foggy:

If I don't want to adjust the output on my board to a perfect .316v, and always normal 1-1&9, 2-2&10, etc., if a channel turns out to be off spec, is there any reason I can't just set 0VU on the board to equal 0VU on the deck, so that the meters match, and then go through the playback and record/bias alignment per the book, using the signal from the particular board channel?
 
I’m not following exactly...what mixing console...what multitrack machine...maybe knowing those things would help me decipher your first post and then I can be of some help. Or...maybe I’M foggy. :D

Is this related to calibrating the tape machine electronics?
 
I’m not following exactly...what mixing console...what multitrack machine...maybe knowing those things would help me decipher your first post and then I can be of some help. Or...maybe I’M foggy. :D

Is this related to calibrating the tape machine electronics?

+1! I too am boggled. I am also worried about the mention of " 0.316V" (neg ten dBV) and "0vu" ? Generally not the same thing.

Then, if there IS a calibrating procedure and you HAVE the numbers, why not do it as "perfectly" as you can?

Dave.
 
...is there any reason I can't just set 0VU on the board to equal 0VU on the deck, so that the meters match, and then go through the playback and record/bias alignment per the book, using the signal from the particular board channel?

Well...if you do that, then if your mixer channel is off...making the deck's channel also equally off isn't really the way to calibrate a deck.
Not to mention...calibrating by the book, has nothing to do with using a signal from a mixer...you need a calibration tape, that is the known reference.

If anything...once you calibrate the deck, you would want to adjust the mixer's channels to the deck...not the deck's channels to the mixer.
 
The only point in an analogue system for gain adjustments away from having 0 read 0 one everything is when a piece of kit has less headroom available by design. Alignment of analogue kit always was scrupulous on the reel to reel machines where things react very differently to misalignment, but on other bits of kit, you very often pushed things - how much depends on the item. I've always subscribed to .7v ish equalling 0VU on all the unbalanced kit I had. Some of the early Grundig kit ha da lower level ISTR, but too long ago now to remember if DIN was different.
 
The result of posting a half-baked idea at midnight! I was hoping to use the tone generator on the board for meter and record alignment w/o having to calibrate the board.
 
M520 ~.316mV across all 8. Same on my Teac 5 (a couple needed adjustments.) But again, posted before I'd really thought about what I was asking...

I'm getting set to calibrate my MSR-16. It's a lot easier to access the trimpots than on the 38. Playback is down on most channels (so I'm wondering if it was calibrated for something other than 456.)
 
M520 ~.316mV across all 8. Same on my Teac 5 (a couple needed adjustments.) But again, posted before I'd really thought about what I was asking...

I'm getting set to calibrate my MSR-16. It's a lot easier to access the trimpots than on the 38. Playback is down on most channels (so I'm wondering if it was calibrated for something other than 456.)

Woah! Before you start tweaking 16 (32?) effing pots I respectfully suggest you get your "precision" hat on and think in a more systematic way.

Lack of care in how you post figures can translate into bad readings or understandings of settings and adjustments? For instance "~ .316mV" That comes out as 316 MICROVOLTS!

Then, when quoting decimals less than one it is good practice to insert a zero, i.e. 0.316 volts then we are left in no doubt about the meaning (I also usually add "rms" where I think it is moot, e.g. guitar signals, often quoted as pk-pk).

To properly calibrate a tape machine you need some pretty tasty test kit plus of course a test tape and a 1/2" one 'o' dem ain't gonna be cheap! Also, do not rely on a digital meter for level readings, even quite expensive "true rms" types are only accurate (but fabulously so!) at power line frequencies. Most begin to fall off past about 2kHz.

Dave.
 
Woah! Before you start tweaking 16 (32?) effing pots I respectfully suggest you get your "precision" hat on and think in a more systematic way.

Lack of care in how you post figures can translate into bad readings or understandings of settings and adjustments? For instance "~ .316mV" That comes out as 316 MICROVOLTS!

Then, when quoting decimals less than one it is good practice to insert a zero, i.e. 0.316 volts then we are left in no doubt about the meaning (I also usually add "rms" where I think it is moot, e.g. guitar signals, often quoted as pk-pk).

To properly calibrate a tape machine you need some pretty tasty test kit plus of course a test tape and a 1/2" one 'o' dem ain't gonna be cheap! Also, do not rely on a digital meter for level readings, even quite expensive "true rms" types are only accurate (but fabulously so!) at power line frequencies. Most begin to fall off past about 2kHz.

Dave.

Good lord Dave.... :)
 
Good lord Dave.... :)

Yeah, sorry for the rant Mr Mod but I was trying to save the OP from what I suspected was a "suck it and see" approach to aligning a tape machine! I admit my evidence for this was slim, based only on his rather sloppy use of numbers but such alignment procedures are not 'trivial' and without a stern, well thought out M.O. you can make things a 'king sight worse!

Dave.
 
Yeah, sorry for the rant Mr Mod but I was trying to save the OP from what I suspected was a "suck it and see" approach to aligning a tape machine! I admit my evidence for this was slim, based only on his rather sloppy use of numbers but such alignment procedures are not 'trivial' and without a stern, well thought out M.O. you can make things a 'king sight worse!

Dave.

I hope you saw the smiley face. :)

Mr Mod? lol! I never understand the mindset of people that think we are assholes with some strange powers. A moderator is just a member of the site that works for free to take care of spam and hopefully keep the site working well. Good lord. I am really tired of the fucking attitudes from members. I am just a guy that wants to help people when I have actual insight to a specific question. Thought being a mod would allow me to help more.

Can't I still have a sense of humor?

Kinda wondering why I bother...

And in case you didn't notice, I am a MOODerator.. :D
 
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So...

Back to the topic. How can we help?

And when you say you’re getting 316mV across all 8 are you talking about PGM group outputs on the M-520?
 
I hope you saw the smiley face. :)

Mr Mod? lol! I never understand the mindset of people that think we are assholes with some strange powers. A moderator is just a member of the site that works for free to take care of spam and hopefully keep the site working well. Good lord. I am really tired of the fucking attitudes from members. I am just a guy that wants to help people when I have actual insight to a specific question. Thought being a mod would allow me to help more.

Can't I still have a sense of humor?

Kinda wondering why I bother...

And in case you didn't notice, I am a MOODerator.. :D

Oh ! No! That wasn't agro Jim! Just me being deferential about my slightly pedantic outburst. I have the GREATEST respect for moderators. I have "been in charge" in a few situations and I know, you cannot fucking win!

Dave. (Sorry Sweets', as you were.)
 
I've never actually worried about absolute levels.My old tape nachines were 300mV for 0VU on the meter. I'd level the group faders on my test signal fed into one input to give 0 on the meters, all the groups would be close to identical fader settings, and I'd see about the same on the tape machine. Replay would produce the same reading on the same tape, and I'd use the same brand to avoid having to recalibrate. 300mV or 312? No idea, is it critical.
 
I've never actually worried about absolute levels.My old tape nachines were 300mV for 0VU on the meter. I'd level the group faders on my test signal fed into one input to give 0 on the meters, all the groups would be close to identical fader settings, and I'd see about the same on the tape machine. Replay would produce the same reading on the same tape, and I'd use the same brand to avoid having to recalibrate. 300mV or 312? No idea, is it critical.

Absolute levels matter if you are using a noise reduction system such as Dolby but no, so long as all your gear is optimized the ACTUAL signal voltage can be pretty much whatever you like.

However, "Operating Levels" are chosen as the best compromise between noise and clipping, i.e maximum headroom. Thus OL will be different for different devices and their use and internal supply rails. For instance, many tape machines used a single 24V supply and so the max line out was limited compared to modern op amps that often run at +&- 18V*. Mixers might have a line output of +4dBu but an internal OL of -2dBu for a recording unit. Broadcast mixers use much lower internal OLs and hence have greater headroom but more noise.

When combining tracks for final use it is nice to have consistent levels.

*I understand +&-17V gives but 1/2 dB less headroom but vastly greater chip reliability?

Sorry Jim, waffling again!

Dave.
 
Geeez. I got lost in all the technical mumbo jumbo. And then mod angst entered in. :D
I just hook everything up and if it doesnt blow up, we're good to go. :D :thumbs up:
 
Good lord Dave.... :)

God had nothing to do with it. :p


I never understand the mindset of people that think we are assholes with some strange powers.

I've never had that thought.... :D ...and I know when I was a mod, no one ever thought that of me. :laughings:


Sorry Jim, waffling again!

Maybe you should get some syrup and go enjoy your waffles quietly for a bit.
I think you're just confusing the shit out of the OP. :)
Heck...I'm even having trouble following your line of thought. ;)
 
God had nothing to do with it. :p




I've never had that thought.... :D ...and I know when I was a mod, no one ever thought that of me. :laughings:




Maybe you should get some syrup and go enjoy your waffles quietly for a bit.
I think you're just confusing the shit out of the OP. :)
Heck...I'm even having trouble following your line of thought. ;)

Last post wasn't aimed at OP but ok. I'll get me coat...

Dave.
 
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