Issues setting tone

gco

gco

Veteran
After setting tone with a dvx and mixpre, sound level is low and distorted.

Camera:
input 2 set to LINE
mic pwr 48v OFF
mic ALC set to OFF

Mixpre:
phantom set to 48v
tone to camera set at -20dB (8th white segment from left). I did wait for the tone level to warm up to its final value.

sound registers between 0 and +8 dB on mixer and limiter kicks in on peaks.
I recorded a test on tape, played it back and it is the same as I am hearing it--lousy. Have to crank the tv volume way up.
Tested this on two different microphones that I know are good and results are the same.
I am missing something here, just don't know what it is yet.
Can anybody clue me in here?
thanks in advance,
gary
 
Try setting the tone at the -12dB mark instead and setting the limiter in the mixer to kick in at around +8. Are you sure you are also getting distortion? or is it only low levels. Keep your levels in the mixer between 0 and +4 and it should be fine.
 
A couple of things...

First, are you sure your camera is set for XLR input? Is it possible you're hearing the built-in mic rather than the mic through the mixer?

Second, I'm not as familiar with the MixPre, but does it send line level or mic level out? You may need to adjust the camera accordingly.

Finally, what mic are you using with your mixer. If it is a lower quality mic, the MixPre can't make it sound better. :-)

Phil
 
The MixPre outputs professional (+4dBu nominal) line level on the XLR outputs, -10dBv prosumer line on the unbalanced mini TRS Tape outputs. The meters are calibrated in actual dBu output so when the +4 meter LED is illuminated, you really do have +4dBu signal at the XLR output. Current practice would be for tone at 0dBu on the meters to be set to -20dBFS in the camera. (Mixers that were intended to use with analog recorders were calibrated so 0VU = +4 dBu output but current digital practice is mixers are calibrated so 0VU metered =0dBu output.)
 
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Ok, I set the pots for tone at -12dBFS. Input 2 is routed to channels A and B so the internal mic is out of the picture. Outputs from mixpre are line level according to owners manual and marks on the unit itself. Input 2 set to line.
Recorded a test using an Octava with levels hitting +4dBU on the mixer as suggested and it does make a difference. This seems to be confirmed by my levels on the lcd display hitting one to two bars into the red which is where I think it should be. So it looks like 0dBU tone should correspond to -12dBFS for the mixpre and DVX.
Everything I had read previously stated -20dBFS but that was in reference to the SD302 and HVX. Looks like my fault for assuming the mixpre/DVX and sd302/HVX would have the same values for setting tone.
Thanks for the help guys!
 
Actually, whether you are using a mixpre or an SD302 into an HVX or a DVX, it is more "correct" to set your levels with the tone at -20dB. If you look at your meters in the mixpre, they go up to +18 and at +20 your signal will distort withing the mixer. This means that you have 20dB of head room between a decent level and distortion. If you want the same dynamic range in your camera you need to tone at -20 where 0 is distortion. At this point, your limiters in the mixpre will be set to +18 or a bit less to tame any peaks in the signal that go over. Now, having said that, for most applications where people speak at normal conversation levels (interviews, not too dramatic scenes, etc.) you want to have a hotter signal to avoid having to bring up the levels too much in post. In that case it is better to set your tone at -12 in the camera, but you want to have your limiters in the mixer set quite lower (i.e. +8) to avoid distortion if the person suddenly starts speaking louder. This setup only gives you 12 dB of headroom If they start screaming... you have to be quick to bring down the levels in your mixpre.

If you are only using one microphone you can always tone channel 1 to -12 and channel 2 to -20 in the camera so if you get distortion on one channel, you are safe on the other.

I hope this makes sense.
 
gco said:
After setting tone with a dvx and mixpre, sound level is low and distorted.

Camera:
input 2 set to LINE
mic pwr 48v OFF
mic ALC set to OFF

Mixpre:
phantom set to 48v
tone to camera set at -20dB (8th white segment from left). I did wait for the tone level to warm up to its final value.

sound registers between 0 and +8 dB on mixer and limiter kicks in on peaks.
I recorded a test on tape, played it back and it is the same as I am hearing it--lousy. Have to crank the tv volume way up.
Tested this on two different microphones that I know are good and results are the same.
I am missing something here, just don't know what it is yet.
Can anybody clue me in here?
thanks in advance,
gary
Click to expand...
with 0 dB tone from the mixer, set the camera level at -20.
Make sure your mixer metering is set to Peak and RMS reading.
Run levels in the mixer up to +20 dB.

Regards,

Ty Ford
 
Pablo, everything you said makes perfect sense and Ty certainly confirmed it.
Until I get some meaningful experience on my own, I'll go with -12/-20 on channels A/B as suggested and see what results I can get this weekend.
Thanks guys!,
gary
 
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