HD100 audio question at DVinfo.net

Brian Luce · January 24th, 2007, 10:09 PM

Regarding the JVC Hd100 camera, If one uses a mixer and is the internal on board preamp being bypassed? Or does the audio signal still go through the camera's built in preamp.

Eric Darling · January 24th, 2007, 11:54 PM

How would using something external to the camera bypass anything inside the camera? The audio on the GY-HD100 inputs is mic/line switchable. If you're in line, there's no pre-amplification running in the camera (or any camera that offers such a switch).

Brian Luce · January 25th, 2007, 12:18 AM

Quote:

Originally Posted by Eric Darling

How would using something external to the camera bypass anything inside the camera? The audio on the GY-HD100 inputs is mic/line switchable. If you're in line, there's no pre-amplification running in the camera (or any camera that offers such a switch).

I really don't know Eric, but on another board, they were saying only high end cameras have the ability to by pass the on board audio preamp. And therefore running a preamp on a camera withOUT that bypass capability is not going to improve your sound significantly cuz the limiting factor is the cameras built in preamp.

Eric Darling · January 25th, 2007, 12:41 AM

Well, I guess the HD-100 qualifies as a "high-end" camera, then. I can tell you this much... The audio quality on the camera is very good - certainly good enough to master from. It's clean as a whistle when using the line inputs. Depending on your field mixer, you may be feeding mic or line level, so check your mixer settings. Obviously, you want to keep the noise floor as low as possible, so always use the line level inputs when connected to a mixer. I only use the mic level switch when an actual microphone is connected directly to the camera (the nat sound shotgun, for instance).

I've done plenty of field audio recording over the years to a wide variety of recorders and cameras. This one definitely ranks as pro quality. I can't hear a difference between it (in either uncompressed 48K PCM when rolling in SD or the MPEG audio in HD mode) and the recordings made on the Varicam, FWIW. Apples to apples, it's a non-issue.

Bill Ravens · January 25th, 2007, 07:42 AM

Unfortunately, just like compressed MPEG video, the compressed MPEG audio isn't the best format in the world to squeeze out some quality hi fidelity musical recordings. It works fine for normal volume voice levels, but, is limited in bandwidth for better quality. The solution, as asked about, is to bypass the compression stage by recording to a seperate audio recorder. If there's any amplification going on, it's fairly irrelevant, it's the comression you want to avoid. Either way, there's no reason not to feed audio to your external recorder and pass it thru to the camera afterwards. There should be no appreciable time delay and resulting loss of sync.

Eric Darling · January 25th, 2007, 10:52 AM

For live music recording, it's always best practice to roll the master sound to a separate recorder.

Bill Ravens · January 25th, 2007, 12:11 PM

I would pass an audio signal from the external recorder(master) to camera, if only so i could use the onboard audio waveform to help sync up the master to the video. As long as there's a fairly short cable run between the audio recorder and the cam, there shouldn't be a sync issue.

Oleg Kaizerman · January 26th, 2007, 01:26 AM

actually , i did a50 day series for Israeli secend channel with this camera on hdv mode , it sounds very well with the compression for the dialog , no problems at all , you just need to run the levels and work with good mics and preamp , in dv mode this camera sounds better then any other camera in its range ( z1 , panasonics and even the twice sony 450 or 500)
i really think that the preamps are by passed since there is a hudge different working with mic or line inputs .
the camera has to line input gain settings , the 12 or 20 reference , the 12 is better for mixers or devices which pull out -10 dbv signal , the 20 for the +4 dbu outputs .
if you work with with +4 or 0 dbu reference tone mixer , dil the the input till you get the next step on the meter after -20 will lit , then go bit back as every dot is 4 db , ride the levels you get at least -10 dbfs lit on your picks
the headphone amp get distortion about in -4 dbfs so dont panic its just the headphone amp , sony cameras distorts on -10 ( hd-900 and similar) .
dont use line outs to send back to your mixer as reference , it doesnt distort but it hissy as hell , actually headphone out have better reference signal till it distort .
excellent camera sound wise if you ask me

Oleg Kaizerman · January 26th, 2007, 01:29 AM

except the music or if you intend go to cinema release i really wouldnt be bother by compression in hdv format , i really would not be bother by anything if i recording in dv format

January 24th, 2007, 10:09 PM	#1
Brian Luce Inner Circle Join Date: Jan 2006 Posts: 2,290	HD100 audio question Regarding the JVC Hd100 camera, If one uses a mixer and is the internal on board preamp being bypassed? Or does the audio signal still go through the camera's built in preamp.

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January 24th, 2007, 11:54 PM	#2
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	How would using something external to the camera bypass anything inside the camera? The audio on the GY-HD100 inputs is mic/line switchable. If you're in line, there's no pre-amplification running in the camera (or any camera that offers such a switch).

January 25th, 2007, 12:41 AM	#4
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	Well, I guess the HD-100 qualifies as a "high-end" camera, then. I can tell you this much... The audio quality on the camera is very good - certainly good enough to master from. It's clean as a whistle when using the line inputs. Depending on your field mixer, you may be feeding mic or line level, so check your mixer settings. Obviously, you want to keep the noise floor as low as possible, so always use the line level inputs when connected to a mixer. I only use the mic level switch when an actual microphone is connected directly to the camera (the nat sound shotgun, for instance). I've done plenty of field audio recording over the years to a wide variety of recorders and cameras. This one definitely ranks as pro quality. I can't hear a difference between it (in either uncompressed 48K PCM when rolling in SD or the MPEG audio in HD mode) and the recordings made on the Varicam, FWIW. Apples to apples, it's a non-issue.

January 25th, 2007, 07:42 AM	#5
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Unfortunately, just like compressed MPEG video, the compressed MPEG audio isn't the best format in the world to squeeze out some quality hi fidelity musical recordings. It works fine for normal volume voice levels, but, is limited in bandwidth for better quality. The solution, as asked about, is to bypass the compression stage by recording to a seperate audio recorder. If there's any amplification going on, it's fairly irrelevant, it's the comression you want to avoid. Either way, there's no reason not to feed audio to your external recorder and pass it thru to the camera afterwards. There should be no appreciable time delay and resulting loss of sync.

January 25th, 2007, 10:52 AM	#6
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	For live music recording, it's always best practice to roll the master sound to a separate recorder.

January 25th, 2007, 12:11 PM	#7
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	I would pass an audio signal from the external recorder(master) to camera, if only so i could use the onboard audio waveform to help sync up the master to the video. As long as there's a fairly short cable run between the audio recorder and the cam, there shouldn't be a sync issue.

January 26th, 2007, 01:26 AM	#8
Oleg Kaizerman Major Player Join Date: Dec 2003 Location: israel Posts: 296	actually , i did a50 day series for Israeli secend channel with this camera on hdv mode , it sounds very well with the compression for the dialog , no problems at all , you just need to run the levels and work with good mics and preamp , in dv mode this camera sounds better then any other camera in its range ( z1 , panasonics and even the twice sony 450 or 500) i really think that the preamps are by passed since there is a hudge different working with mic or line inputs . the camera has to line input gain settings , the 12 or 20 reference , the 12 is better for mixers or devices which pull out -10 dbv signal , the 20 for the +4 dbu outputs . if you work with with +4 or 0 dbu reference tone mixer , dil the the input till you get the next step on the meter after -20 will lit , then go bit back as every dot is 4 db , ride the levels you get at least -10 dbfs lit on your picks the headphone amp get distortion about in -4 dbfs so dont panic its just the headphone amp , sony cameras distorts on -10 ( hd-900 and similar) . dont use line outs to send back to your mixer as reference , it doesnt distort but it hissy as hell , actually headphone out have better reference signal till it distort . excellent camera sound wise if you ask me

January 26th, 2007, 01:29 AM	#9
Oleg Kaizerman Major Player Join Date: Dec 2003 Location: israel Posts: 296	except the music or if you intend go to cinema release i really wouldnt be bother by compression in hdv format , i really would not be bother by anything if i recording in dv format