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PD-150 / ME-66 wK6 / Sound Devices MixPre
I’ve posted on this subject some time in the past, and have understood that the PD-150 is a rare bird as the xlr connectors do not receive a true line level.
We have the ME66 going into the MixPre, and then back out to the PD150. Here is what is happening, and maybe someone can give me some ideas. We are doing a documentary currently in Spain, and I have a sound guy with the MixPre and Sennheiser shot gun. Whenever we record music it distorts slightly. Levels are fine, as expected, but there is some distortion. We have the MixPre set so as to keep the gain only slightly into the red – by that I mean, it’s peaking only one or two lights occasionally. Sorry I don’t have the MixPre near me now so I can’t give the exact db correlation on the lights.
I’ve been told that a -10db pad will help, but the pad, in my view, takes away the nice crisp signal. It just seems more muffled when you put the pad in.
Any suggestions would be appreciated. Someone suggested I get the mic red dotted, others have suggestion the BBC modification. The mic cannot go direct into the camera, because the distortion is clearly there.
Thanks.
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4 Replies
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Suggest you sit down in front of a boom box with your rig and do some serious benchmarking.
To start, turn on the meters on the PD150, turn the MixPre down until it peaks at 0, not in the red. Try with the 150’s autogain off and with it on. Try the line input. Try the mic input with (internal) pad. Try all of it. Turn the 150 to manual gain and turn it up. Turn it down. Peak the MixPre at -6, at -12. Find out what it does.
Many people will recommend peaking at -12db for digital recording. Even a momentary transient above 0 that you can’t see on the meters can sound horrible, especially with music.
Lay the best settings on tape with visual and audio slates, pull them into your editor and see what you’ve got.
Get a headphone return cable from the PD150 back to the MixPre so the sound guy can instantly evaluate what the 150’s preamps and gain structure are doing to his signal. Give him some playback in the field as well.
I suspect that peaking the MixPre at -6 or -10 is going to fix the problem, but that recommendation is no substitute for going through the above process.
Whoa, I just looked at the MixPre online – that’s not very many segments in the output meters! No segments between -15 and 0 is not very friendly. But it does have tape return – use it.
If you weren’t on a PD150 I’d say just send tone at 0 and set manual gain on the camera to -12, then peak program material to 0 on the MixPre. The problem with the 150 is that you never know until you benchmark whether it will perform better in automatic or manual gain (and its meters have no markings). How about setting it for autogain in one channel, and manual gain in the other (if you’re just depending on the single mic.)
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SETH,
Good advice. we use a FP-33 Shure field mixer and the -12 setting is about right in manual mode. Also important to have a headphone return line so the sound guy can hear what he is getting at the camera.Dick
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Make sure you’re looking at peak readings instead of RMS. It sounds like you are catching peaks. Pull back. Last time I worked with a PD150 I set tone at -20 and we tested it. It was OK, but I could hear the noise floor. I engaged my Sound Devices 442 limiter and pulled the mic close to me and spoke loudly. Peaks were at -8 or -12.
Knowing that the limiter would catch the peaks, I increased the camera audio input gain control til the audio was peaking at -3 dB. That seemed to work fine; good level, no clips, less system noise. Try it before you shoot. See what you think.
Regards,
Ty Ford
Ty Ford’s “Audio Bootcamp Field Guide” was written for video people who want better audio. Find out more at https://www.tyford.com
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There is some good and useful information here.
HTH,
Davehttps://www.sounddevices.com/tech/pd150.htm
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