Varicam35: Sound quality from VC-35 vs dedicated audio recorder is too large

L

lonewolf2koc@hotmail.com

Well-known member
I'm not sure what I did wrong on the VC-35 but the sound quality from a dedicated sound recorder (an old Sound Devices 702T) recording in stereo with a mid-priced Audio Technica BP4029 shotgun mic always sound better than what's coming from the VC-35.

I've been setting the VC-35 to AGC. Perhaps setting it to manual may help a bit on the VC-35. Recording general ambience wildlife at a tropical forest.

The quality from a dedicated recorder has always sound better every time. It sounds cleaner, more dynamic range, and more pristine and accurate. The VC-35 recorded sound is flat. Not much nuances at all. All from the same mic and cable. Very disappointed. Should I give up the sound recording on the VC-35 and use a dedicate recorder? At least I was hoping for something similar but it's not even close. Don't like to be brining too much gear on location and having to sync up in post prod.
 
From a sound perspective, AGC is a bit like setting a consumer camera to 'Full Auto' -- or at least to auto-iris. It may be fine for a reference audio track, but you'd never want to rely on it.
The sound recordists I work with start by turning off anything that's 'auto' -- then they set the inputs to line level and connect to their mixer. Basically that means their mixer - in addition to being used to set levels - is being used as the mic preamp. As it happens, Sound Devices puts great preamps in their mixers -- so if I'm needing to record decent sound and I don't have a recordist with me, I use an old Sound Devices Mix Pre (2 channel) mixer - small and lightweight - and use it as my preamp so I can go into the camera at Line Level.
Why don't you do a test and compare the audio actually recorded in the 702T with audio from the 702T that goes into the camera at a properly adjusted line level and is recorded in camera. For many situations I would guess you couldn't tell the difference. Trying to compare anything to AGC audio just isn't a fair comparison.
 
I'll switch to MANUAL recording input and evaluate from there. The audio controls are buried via menus and there's no direct manual access found on their 2/3" ENG cams. For general ambient stereo sound recording, I don't think that the VC recorder is that bad in quality. It may not be as good as the Sound Device 6## or 7## series, but shouldn't be way off in quality. I strongly think the AGC is boosting and bringing everything up like you mentioned. Will have to get used to checking the audio levels on the menu. I'm not complaining much because the Alexa Mini, you'll have to buy a very expensive 6-pin LEMO-XLR to get the audio in. At least the VC series there are still analog XLR inputs to use!

This is skeleton 1-man crew. At times I can't bring an assistant. So can't bring too much gear on remote location and have to keep everything to absolutely bare min. Batts, P2 Express media, tripod and not much accessories.
 
I'd say AGC is probably your weak link there(and possibly the internal mic-pre's-maybe...). The 'audio recording' section of the camera, at 24 bit/48khz, is every bit as good as a 6-series SD recorder*.



*Yes, the 633 and 688 will go up to 192khz, which is more than the 664 which tops out at 48khz, but no one is generally recording nat's or human voices at that high of a sampling rate.
 
Had more chance to record using the same average Audio Technica BP-4029 (in matrixed wide stereo mode) directly to the VC and another BP-4029 (same stereo setting) directly to the old SD 702T via the 5-pin to two male XLRs. This time it's at a soccer game with small-medium crowd. And for whatever reasons, the old SD 702T has a very wide and spacious dynamic range. VC-HS is good in manual level, but SD 702T sounds so much richer and it really get rid a lot of ambient noise. The SD 702T gain was set to mic, normal, linked stereo tracks. Level is set around 40. Even though the VC-HS has 24-bit and similar tech specs, the final resulting sound quality difference was considerable. I was able to place the SD 702T pretty much anywhere close to the source w/ out cumbersome XLR cables and w/ the Ambient TC, no need to worry about manual up in post. This makes me rethink that why on bigger budget productions they have a dedicated sound recordist for a reason...

I also have the Zoom F8. It's pretty good but just not the same class as SD. The cost for a used Sound Devices 702T is roughly the same as the Zoom F8. So there has to be a reason for the high cost even though the 7## series is not widely used these days. Tempted to get their 744T over the Zoom F8.
 
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One of the main differences, is the Mic PreAmps on the SD, they are in a class of their own for field mixer/recorders.
 
Did you ever compare the same audio recorded internally to the card on the 702T with audio output at line level from the 702T and recorded (line level in, manual, setting tone at -20db) on the VC? Any other comparison is more about the input preamps, limiter circuits, headroom and auto circuitry. This would answer the question of whether to use an external recorder, or whether all you really need is an external mixer with Sound Devices quality preamps and limiters.
 
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