Audio Problems Anyone?

Paul Mogg · June 6th, 2004, 11:43 PM

I now hear no difference between the sound on the JY-HD1OU and my much more expensive Ikegami ENG camera, using the same Lav's that is. So I think it would compare favorably with any prosumer cam sound.

Paul

Glenn Gipson · June 8th, 2004, 02:45 AM

The Audio is unbalanced, right? How would I go about making the audio balanced? Would I need something like a MixPre?

Bill Piedra · June 8th, 2004, 11:30 AM

Glenn -

Thats's a really good question. I would think it would only cost a few dollars for the circuit to make the audio balanced. I can't figure out for the life of me why the didn't make it balanced.

In a book called Producing Great Sound for Digital Video the author includes schematics for building your own circuit using radio shack components. I wonder if the circuit would fit inside the little XLR box they give you with the HD10.

Any comments?

Heath McKnight · June 8th, 2004, 11:41 AM

A friend of mine who did audio for Spike Lee explained me the whole balanced into unbalanced. Of course, I forget, so I'll ask him again.

As to why JVC did that, it's probably just a matter of costs.

heath

Bill Piedra · June 8th, 2004, 11:55 AM

The last page of this month's DV Magazine has a detailed explanation. The way I understand it, in it's simplest form is this:

In a balance ciruit, the audio comes across two wires 180 degrees out of phase (negative and positive voltage). Think of two waves that are mirrors of eachother. Electrical noise on wire would appear as a spike on these two waves. A balanced circuit ignores these spikes, since the circuit can only 'see' the current on the wire if there are both a postive and matching negative signal.

To create a balanced circuit all one would need to add is a small transformer of sometype to filter out the noise. This type of ciruit was orginally invented by the phone company a long time ago.

My electrical engineering terminology is a little rusty - so please forgive me. I hope this helps.

Heath McKnight · June 8th, 2004, 09:48 PM

I understand it's three wires providing a balance. The third one provides a back-up, much like how most power sockets have three instead of two prongs.

hwm

Bill Piedra · June 8th, 2004, 11:45 PM

I thought the third wire was a ground wire -- all properly engineered circuits should have a ground, but I could be mistaken in this case.

Heath McKnight · June 9th, 2004, 10:29 AM

Yeah, you're right! D'oh! on my part...

hwm

June 6th, 2004, 11:43 PM	#46
Paul Mogg Major Player Join Date: Apr 2003 Location: San Francisco CA Posts: 386	I now hear no difference between the sound on the JY-HD1OU and my much more expensive Ikegami ENG camera, using the same Lav's that is. So I think it would compare favorably with any prosumer cam sound. Paul __________________ Paul

June 8th, 2004, 11:41 AM	#49
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	A friend of mine who did audio for Spike Lee explained me the whole balanced into unbalanced. Of course, I forget, so I'll ask him again. As to why JVC did that, it's probably just a matter of costs. heath __________________ My Final Cut Pro X blog

June 8th, 2004, 09:48 PM	#51
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	I understand it's three wires providing a balance. The third one provides a back-up, much like how most power sockets have three instead of two prongs. hwm __________________ My Final Cut Pro X blog

June 9th, 2004, 10:29 AM	#53
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	Yeah, you're right! D'oh! on my part... hwm __________________ My Final Cut Pro X blog

June 8th, 2004, 02:45 AM	#47
Glenn Gipson Major Player Join Date: Jan 2003 Location: Plainfield, New Jersey Posts: 927	The Audio is unbalanced, right? How would I go about making the audio balanced? Would I need something like a MixPre?

June 8th, 2004, 11:30 AM	#48
Bill Piedra Regular Crew Join Date: Dec 2003 Location: Manchester CT USA Posts: 109	Glenn - Thats's a really good question. I would think it would only cost a few dollars for the circuit to make the audio balanced. I can't figure out for the life of me why the didn't make it balanced. In a book called Producing Great Sound for Digital Video the author includes schematics for building your own circuit using radio shack components. I wonder if the circuit would fit inside the little XLR box they give you with the HD10. Any comments?

June 8th, 2004, 11:55 AM	#50
Bill Piedra Regular Crew Join Date: Dec 2003 Location: Manchester CT USA Posts: 109	The last page of this month's DV Magazine has a detailed explanation. The way I understand it, in it's simplest form is this: In a balance ciruit, the audio comes across two wires 180 degrees out of phase (negative and positive voltage). Think of two waves that are mirrors of eachother. Electrical noise on wire would appear as a spike on these two waves. A balanced circuit ignores these spikes, since the circuit can only 'see' the current on the wire if there are both a postive and matching negative signal. To create a balanced circuit all one would need to add is a small transformer of sometype to filter out the noise. This type of ciruit was orginally invented by the phone company a long time ago. My electrical engineering terminology is a little rusty - so please forgive me. I hope this helps.

June 8th, 2004, 11:45 PM	#52
Bill Piedra Regular Crew Join Date: Dec 2003 Location: Manchester CT USA Posts: 109	I thought the third wire was a ground wire -- all properly engineered circuits should have a ground, but I could be mistaken in this case.