what frequency do YOU use for LF calibration?

  • Thread starter Thread starter FALKEN
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FALKEN

FALKEN

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I tried several on my otari last night. 100 hz, 400 hz, 50 hz. Still, the low frequency record and playback did absolutely nothing on either side. I was able to calibrate playback using the LF compensation but the eq adjustments still do nothing. ????????? (since each frequency came out level I figured I was good to record on the otari). Going to do my Fostex tonight and was just wondering where everyone stands.
 
For those machines that have the adjustment, 100 Hz is fairly standard.
 
There is no low frequency eq. The low is the speed. Each speed has it's own high eq adjustment for playback and record and thats all you can change other than the low freq comp. Paul.
 
Falken,

Just to clear up any confusion… there aren’t many machines that allow adjustment of low frequency record EQ. I assumed you were referring to the low frequency playback adjustment.

I don’t know about the MX-5050, but machines like the Fostex E-16 and TASCAM MSR-16 have no adjustment for reproduce low freq compensation.

You just have to check that the lowest and the highest are within 3 dB (or whatever the spec is) of 1kHz @ 0 VU.

If a machine has reproduce low freq compensation, the best way to set it is by recording the tones on the machine you are calibrating and adjust the playback using that recording. You won’t get the right results using a pre-recorded MRL tape for this step because the compensation is for your particular machine's record EQ characteristics.

Tim
:)
 
ha, yes, I caught this as I was doing the calibration.

so, I went back and forth between the 1khz and the 10khz tone adjusting the repro level and the eq level and got them as flat as possible. but the 100 hz tone still comes out at about -1 db. at least it is relatively even between the two sides but I have tried compensating and it looks like its not going to happen (on the fostex) unless there is something you know that I don't?

on the record side it has a high eq and a low eq for each the high and low speeds so I think it is supposed to affect the balance going to tape; except no amount of tweaking on any of the knobs makes a bit of difference on the output reading. ????
 
FALKEN said:
ha, yes, I caught this as I was doing the calibration.

so, I went back and forth between the 1khz and the 10khz tone adjusting the repro level and the eq level and got them as flat as possible. but the 100 hz tone still comes out at about -1 db. at least it is relatively even between the two sides but I have tried compensating and it looks like its not going to happen (on the fostex) unless there is something you know that I don't?

on the record side it has a high eq and a low eq for each the high and low speeds so I think it is supposed to affect the balance going to tape; except no amount of tweaking on any of the knobs makes a bit of difference on the output reading. ????
Click to expand...

falken, I don't remember TOO much, but 100 hz is the freq used for LF adjustements. And I remember not being able to adjust some levels completely, since the pots wouldn't turn far enough. I'm guessing this is an azimuth problem or something. But getting it within 1 db is plenty close enough in my opinion.
 
FALKEN said:
I tried several on my otari last night. 100 hz, 400 hz, 50 hz. Still, the low frequency record and playback did absolutely nothing on either side. I was able to calibrate playback using the LF compensation but the eq adjustments still do nothing. ????????? (since each frequency came out level I figured I was good to record on the otari). Going to do my Fostex tonight and was just wondering where everyone stands.
Click to expand...

At 15 ips IEC1, for low LF playback EQ, I check the levels on the low tones: 30, 60, 120 and try to get as flat a response as possible but without introducing much of a peak in the 50-60 Hz range. I want to turn 30 Hz up as close to 0 dB as I can, but not at the expense of creating a hefty bump at 50-60 Hz. So I usually tolerate +1 dB peak in the 50-60 Hz range and live with wherever 30 Hz is. Same basic idea at 30 ips AES, try to set a flat response and minimize any bass bump. I use the same calibration tape, so my lowest tone is 60 Hz and my highest tone is 40K. My 3M machines don't have low frequency rec eq adjustments, nor does the Ampex AG-440 I'm still waiting to sell. I think Studer machines often had LF rec eq.

Cheers,

Otto
 
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