TAPE CALIBRATION QUESTIONS

general questions, comments and ideas about recording, audio, music, etc.
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al burn
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TAPE CALIBRATION QUESTIONS

Post by al burn » Thu Dec 11, 2003 6:28 am

I have a Fostex G16 1/2inch 16 track recorder and I'm having problems calibrating it.

I know it's operating level is 320 nWb/m and my MRL tape is 320 nWb/m referance flux (MRL cataloge 31J329: SPEED 15ips, EQ IEC-1, MULTIFREQUENCY @ 0db & -10db) All the tones EXCEPT 1K are -10db

I am having problems with the 0db & -10db

The owner's manual tells me to play the 1k tone and to set the REPRODUCE LEVEL (0db) and after that play the 12.5K tone and adjust the REPRODUCE EQ so that it is also (0db) the problem is that the 12.5K tone is -10db and dose not regester 0db WHAT AM I SUPOSED TO DO??????

jerrymac
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Re: TAPE CALIBRATION QUESTIONS

Post by jerrymac » Thu Dec 11, 2003 8:45 am

First off, I'm really not familiar with that machine, but here goes:

After you've adjusted the 1K tone (at 0db) and then played the -10dB 12.5k tone, does the meter ride at about -10? Or higher? Lower? (the 12.5k tone, that is)


I'd say try and adjust it for -10, but you are probably going to find that the adjustment accuracy is going to be all over the place.

Other than buying another MRL, which sucks, I know, try adjusting it for -10, and then record a cd out all your busses and have a listen to the tracks individually on the tape head. Maybe adjusting it to -10 is going to give you wildly different sounds on each track, maybe it it'll be OK. Maybe you could give it a final tweak by ear.

jerry

Recman
audio school graduate
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Re: TAPE CALIBRATION QUESTIONS

Post by Recman » Thu Dec 11, 2003 6:17 pm

Hello:
I own a G16 so maybe I can help. Or not. Unfortunately the meter resolution will not be accurate enough at -10db. They provide a high resolution mode for the meters during calibration. Is 500 or 800hz also at -10db? If not, the calibaration is that far off. I have never seen an alignment tape recorded at 2 incomplete levels. Usually you would have only 1 or 2 complete tone sets. Look towards the end of the tape to confirm that there aren't the tones you are looking for there. I just purchased a G16s for a parts machine that was more out of calibration than the 10 db you speak of. If you are in my area you could use my Fostex alignment tape. The G16s came with one but I have not checked it out.
I am in Portland OR.
Recman
Studio 84

If it's too loud - you're too old
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al burn
pluggin' in mics
Posts: 31
Joined: Sun Jun 08, 2003 1:20 pm
Location: sacramento, CA

Re: TAPE CALIBRATION QUESTIONS

Post by al burn » Fri Dec 19, 2003 12:24 pm

the MRL has ref. flux 320nWb/m for 0db 1K at head and tail and -10db frequencies: 500hz, 8k, 16k, 500hz, 10k, 31.5hz, 63hz, 125hz, 250hz, 500hz, 1k, 2k, 4k, 8k, 10k, 12.5k, 16k in the middle. This is how the MRL tape is made

I have been going back and forth between the fine adjust CALABRATION METER for 1k 0db and the NORMAL METER for the -10db frequncies and adjusting acordingly. I think that's right???

chemicalpink
takin' a dinner break
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Re: TAPE CALIBRATION QUESTIONS

Post by chemicalpink » Sat Dec 20, 2003 6:31 pm

somthing aint' right here, first off a 320 nanoweber tone reel
is really a +4 operating level and all the tones should be at
0 (+4) unless this real is different then all I have used.
I would call jrf magnetics and have them sort ya' out. http://www.jrfmagnetics.com

soundmaniac
alignin' 24-trk
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Location: Allentown, PA

Re: TAPE CALIBRATION QUESTIONS

Post by soundmaniac » Sat Dec 20, 2003 10:45 pm

I'm guessing you've got a "G" 320 tape. G320 tapes are made for European equipment.....since they use PPMs (peak meters instead of VUs) that can accurately read levels at -10. The VUs on your Fostex can't. If you read the pamphlet that comes with MRLs ( I think you can also download it from their site) it explains that whole mess in greater detail.

I'd say it would be a major pain in the ass, if it's even possible at all, to accurately calibrate your machine with that tape, so you best bet would be to just shell out the dough and get a new tape.

al burn
pluggin' in mics
Posts: 31
Joined: Sun Jun 08, 2003 1:20 pm
Location: sacramento, CA

Re: TAPE CALIBRATION QUESTIONS

Post by al burn » Tue Dec 23, 2003 1:43 pm

the G16 has PPM meters

the MRL manual states: 320nWb/m that the 0db 1k corresponds to the fluxivity for 3% THD for PPM meters about 9db higher than 320 nWb/m

on are Otari mx80 at 0db it's 1% THD

should I use the -10db tones to correspond to 0db on my meter or is the 0db 1k tone the reforence for 0db on my meter

ladewd
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Re: TAPE CALIBRATION QUESTIONS

Post by ladewd » Wed Dec 24, 2003 8:44 am

soundmaniac is right. 15ips IEC alignment tapes have the high freqs 10db down from the reference. So set your hi freqs to -10vu and the reference 1k tone to 0vu. I'm assuming this machine has IEC equalization? Or maybe you're doing some sort of custom alignment?

If not, buy yourself a 15ips NAB alignment tape. You'll find that 1k and 10k are at the reference level on those tapes.

Merry Xmas
CA

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