Topic: Calibrating a SVU-1

[BobbyHurley]

Question for those running SVU-1 meters with a JB3, how much fiddling with the cal-pots did you have to do before you were good to go on levels?  The instructions included with the unit and those I've found online are all geared towards synching the SVU-1 up with the recording meters on a videocamera.  The cal-pots are in the "10" position currently but I have not had opportunity to use the SVU-1.  I'm not a big fan of adjusting trim pots during a show.  Since I'm running an Oade m248 (no meters) and a mod-SBM-1 (no meters, only "over" lights) in front of the JB3, I needed something more to monitor recording levels.

I know there is a way to calibrate some toys using white noise/static off FM radio, but not sure about using it to calibrate this.

Anybody found a tried and true method?

Also, where can I find a pre-made rt angle stereo mini (male) to rt angle RCA cable (male, L&R)  ?

[johnw]

I made a 10 second 440Hz test tone with Audacity I think and used that. I individually calibrated the pots against that and then put electrical tape over the recessed area the pots were in so they couldn't be accidentally changed. As for right angles, I picked up some solderless right angle connectors at radioshack and tore up an old cheap cable since the quality didn't matter.

[Ray76]

Question for those running SVU-1 meters with a JB3, how much fiddling with the cal-pots did you have to do before you were good to go on levels?  The instructions included with the unit and those I've found online are all geared towards synching the SVU-1 up with the recording meters on a videocamera.  The cal-pots are in the "10" position currently but I have not had opportunity to use the SVU-1.  I'm not a big fan of adjusting trim pots during a show.  Since I'm running an Oade m248 (no meters) and a mod-SBM-1 (no meters, only "over" lights) in front of the JB3, I needed something more to monitor recording levels.

I know there is a way to calibrate some toys using white noise/static off FM radio, but not sure about using it to calibrate this.

Anybody found a tried and true method?

Also, where can I find a pre-made rt angle stereo mini (male) to rt angle RCA cable (male, L&R)  ?

from MMMATT

no prob ray, not a lot of time now but I will give you the basics.  I'm sure you understand that an ideal recording situation is to have the highest peak in a concert be just under the -0- db mark.  If you record over -0- db you will clip your recorder and if you go too far under the music will be distant unless you normalize (increase the overall volume of the recording [by track or by set] to make it the same volume as a normal cd).  The svu does 3 things if used properly:  1. it will give you an acurate way to keep you levels just under clip.  2.  it will help you properly ballance your right and left levels  3.  and it will help trouble shoot your recording device.
     In order to use this properly and get all of the bennifits you need to connect the unit to the "auk out" on the back of the jb3.  for this you will need a 1/8" stereo male > mono L&R RCA male cable.  The quality doesn't really matter although you should always use the same cable for consistancy... as we know better quality cables will produce a stronger signal in our recording chain, but since this isn't actually in the chain it is just based on how you calibrate it.
     As far as calibration goes, you should use  the rest of your rig and a sound source.  I created a white noise test tone by using "audacity" which is a freeware program.  I think many audio programs can create a test tone wav, but that is what I used at the time.  I made this wav about 30 sec long and burned it to a cd.  I then set my mics up perpandicular(one on top of the other pointing directly at the center of the speaker cabinet about 1' away) to one of my speakers on my stereo and turned the ballance on the stereo all the way to that side.  I then played back at amoderate level and adjusted the ua-5 so that the meters on the jb3 were both just under peak.  Then I adjusted the svu so that l&r were ballanced and peaking as high up as possible.  Then I hit record, and recorded about 15sec of the noise.  This is the last time you will refer to the jb3 meters during this process.  They are not only tough to read but are inacurate as well!
     Then download your little recording to your pc and open it up in your audio program.  Check the peak level on each channel seperately and write them down.  I had mine within 1% (-0.1 db) from L > R and that is certainly not a noticiable difference.  You most likely won't be that close yet.  If you left channel is at -0.4 db and your right is at -0.7 db you will want to increase the levels on the ua-5 a tiny bit on the left and 2 tiny bits on the right, readjust the svu so the L & R are ballanced and record, DL, and test again.  Do this untill you are at about 98-99% or -0.1 - -0.2 db equally on each channel.  When you finally get it right, you should remember the top light that was flashing on the svu and that is your peak.  Mine ended up being the first red light which is cool except I'm color blind and can't see the red ones very well.  I took a tiny drop of whiteout and marked each of the calibrated peak lights so that about 1/2 the led was covered.  This way I am looking for the "shape" of the light (the light doesn't look round any more) instead of the color and that worked for me very well.

Hope this helps!

[BobbyHurley]

Fantastic advice from both of you guys.

Just created a test pattern CD and will enjoy annoying the family with it this evening!

[Ray76]

Fantastic advice from both of you guys.

Just created a test pattern CD and will enjoy annoying the family with it this evening!

no problem my friend.

[bluelawn]

+T, i'll be needing this early next week 
thanks,
seth

[T.J.]

has anyone done a similar test matt suggests w/ wavelab 5.0? i'm trying to get a test tone using WL 5.0 and can't figure out how to do it. i think i have to use audio signal generator, but not sure how to set it up.
any help is appreciated.
T.J.

[Ray76]

has anyone done a similar test matt suggests w/ wavelab 5.0? i'm trying to get a test tone using WL 5.0 and can't figure out how to do it. i think i have to use audio signal generator, but not sure how to set it up.
any help is appreciated.
T.J.

i used wavelab 5, audio signal generator, sine wave. looped it and recorded. you just want something constant, so that works. they have sawtooth, etc....click "generate" and cut and paste the signal to loop it.

[willndmb]

i made a file in cool edit pro

[Ray76]

i made a file in cool edit pro

right on,. wavelab does it too though!

[T.J.]

ahh..i got it. thanks bigray and everyone else for the ideas. a round of +T

[dklein]

Even easier than generating test tones just - tune your FM radio to an in between spot and use the hiss.  If you plug the headphone out from your stereo into the recording input, you can adjust the stereo's volume until you're just at or under clipping on the recorder/a>d, then calibrate your SVU accordingly.

You don't need to run mics to calibrate meters.

[CaptMax]

Even easier than generating test tones just - tune your FM radio to an in between spot and use the hiss.  If you plug the headphone out from your stereo into the recording input, you can adjust the stereo's volume until you're just at or under clipping on the recorder/a>d, then calibrate your SVU accordingly.

You don't need to run mics to calibrate meters.

thanks. +T