No scope Azimuth Adjustment

[acorec]

OK, since I am into analog again in a big way, I have this to share with the analog community. May save you some time and headache...........



You can adjust your azimuth, and be as accurate as with the scope. Just try this.

All consoles are "Voltage amplifiers", and all of the VU meters on professional consoles (as well as most Semi-pro boards) read voltage and not power.

Two equal and in-phase voltages will add by 6db when placed on the same buss.

First patch the tape recorder to 2 different input channels of
your board, making sure that the board's eq is out, and that there are
no Echo Sends or Aux Sends on. Then select just one channel (Track #1)
and send it to any one buss (Buss 1 out of the console).
Set this one channel's fader level on the console so that
your buss output VU meter reads -6 VU.

Then turn OFF that channel.

Next turn on your other channel, (it would be Track 2 for a 2 track, track 4 for a 4 track, track 16 for a 16 track and track 24 for a 24 track) send it to the SAME buss as the other channel you just setup, again set that track's console fader level so the buss output meter again reads -6 VU.

Now both channels are set to read individually at -6 VU on the SAME buss Meter.

Then turn BOTH channels on. Since two in-phase VOLTAGE signals should add together by 6 db, you now should be reading 0VU on the meter.

If the meter is very near 0 VU and is stable you're ok. Make sure to check other frequencies. If the meter reads less than 0 VU, adjust azimuth until the meter reads as close to 0VU as possible, with as little meter movement as possible. Make sure to re-set your -6 vu levels on each channel after azimuth adjustments. You have to check azimuth with more
than just one tone (use 10khz and 15khz). Once you have
correctly set azimuth, all tones should read close to 0 VU and be stable.

If all goes well, you have just set your azimuth as accurately as with a O'scope.

This will take some practice, but it works great.

Good Luck.

[The Ghost of FM]

What I used to do with my cassette decks which always seem to drift horribly and quickly because of their spring loaded head mounts was I would put on a well made, store bought pre-recorded tape, plug in a pair of headphones to the amp or mixer, switch the amp or mixer into mono and then while listening to the music, adjust the azimuth screw until I heard a maximum treble response in the cans.

Once done, you could switch back to stereo and the high end response would sound the same as in mono and that would basically get the azimuth adjustment within a pretty close to perfect setting.

Acorec's method seems similar in approach and perhaps even more scientific but I always like to trust my ears first.

Cheers!

[Han]

But, when azimuth is set 100% good and you record a signal to track 1 and to track 24 ( or 2 and 23), both exactly the same level and you put one of the channels out of phase, you should read (and hear) nothing.

Please correct me if I'm wrong.

[The Ghost of FM]

Only if the levels are IDENTICAL and you are placed perfectly between the speakers and they are also set up in perfect phase in a perfect acoustical room.

Then, sure!

No problem.

Cheers!