Y xlr adapter necessary?

[xopoe]

hi,
i just got my audio package from b & h. the guy there said it would be a good idea to feed my single boom mic, without a mixer, through a Y xlr adapter into both channels so i would have a back up. this made sense to me at the time so i got the Y adapter (more expensive than a 25 foot cable) but i just realized that the dvx100a is able to record one input to 2 different channels. is using the Y adapter overly redundant? (theoretically, one of the camera connections could go bad and so the Y adpater would provide a physical backup). and if it is a good idea to have the Y adapter, would i run phanton over just one input or over both?
thanks!

[oleg]

he is a good salsman :-), you dont need it , another plug in the chain is another problem .

[Barry_Green]

I'd agree -- less cables = less problems. Return it, if you can.

[Guest]

I thought part of the reason to do a split was to record at 2 differeent levels. That way if you get too loud of sound (distortion) you could switch to the lower recorded track.

[xopoe]

that was my thinking as well, but if you set it so that input 2 is recorded to both channels, then you can adjust each channel accordingly. right?

[Barry_Green]

You're both right. What we're saying is, you don't need a cable to do that -- the DVX can do it by itself, if you plug the mic into channel 2 and tell both tracks to record their sound from channel 2.

[xopoe]

and so you adjust the levels by using the knobs, and not by setting mic gain1 to -50db and mic gain2 -60db (or vice versa)? which with only one xlr going into input 2, would have no effect?
after everything i've read on this subject, i'm still having a hard time understanding the difference between mic/line levels (0db, -50db, -60db) and setting levels manually with the knobs (which also adjusts gain?).

[PaulK]

and so you adjust the levels by using the knobs, and not by setting mic gain1 to -50db and mic gain2 -60db (or vice versa)? which with only one xlr going into input 2, would have no effect?
after everything i've read on this subject, i'm still having a hard time understanding the difference between mic/line levels (0db, -50db, -60db) and setting levels manually with the knobs (which also adjusts gain?).

I'm a little confused by the above as well. Barry, Oleg, or another guru, care to comment please? :)

[oleg]

if you shoot with candle lights , you open the diafragm to the minimun toget the light do some effrct on the ccd ,=-60db

if you shoot with 500w you open the diafragm to 2.8 and less =50db
if you shotting with 20000kw ksenon you put nd9 and close to 22 thats =line
:-)

[PaulK]

Once again, thanks for the reply, Oleg. :)

So the difference between a LINE and MIC is still confusing me.

The manual says "When connecting an audio component, set the INPUT1 switch or the INPUT2 switch to the LINE position. ...the recording level is adjusted using the AUDIO controls."

Then it says "When connecting an external microphone, set the INPUT 1 switch or the INPUT 2 switch to the MIC position." The manual doesn't say anything about using the AUDIO controls in this case, only using the MIC GAIN 1 & 2 in the menu (-50/-60 dBu).

So, here are my questions:

1) What is the difference between a "audio component" and a "mic?"

2) If the INPUT switches are set to MIC position, are the AUDIO controls (dials) bypassed, i.e., not used to control recording level?

[Scottdvx100]

I'm not a sound expert but here's my experience.
A mic needs to be amplified but a line input does not since it should already be at a reasonable level. If you ran your mic into a field mixer then you would take the output of the field mixer into the camera and set it to line instead of Mic.

The volume controls still work whether it's Mic or Line. Normally you'd set it to a fixed volume if it's from a line input (such as a mixer) and control it during recording at the mixer instead.

[PaulK]

Thank you, it all makes sense now. :)

[xopoe]

if you shoot with candle lights , you open the diafragm to the minimun *toget the light do some effrct on the ccd ,=-60db

if you shoot with 500w *you open the diafragm to 2.8 and less =50db
if you shotting with 20000kw ksenon you put nd9 and close to 22 thats =line
:-)

so, in the above analogy, the volume controls on the camera (or on a mixer) would be the equivalent of adjusting the f-stop by thirds around f2.8, f22?? or is it something else entirely?

[oleg]

yoy might thinking that way or more likely db push or negativ push :-), and then hier soundman for the gob :-)

[xopoe]

actually, that makes sense now. you MATCH levels (exposure) but ADJUST volume/gain (push/pull). so, if you wanted to record one channel hotter than the other, you would do that by setting one channel to -50db and one channel to -60db. the sort-of equivalent of bracketing in photography (where i'm coming from). i hope i have it right now.

[ullanta]

The manual says "When connecting an audio component, set the INPUT1 switch or the INPUT2 switch to the LINE position. ...the recording level is adjusted using the AUDIO controls."

Then it says "When connecting an external microphone, set the INPUT 1 switch or the INPUT 2 switch to the MIC position." The manual doesn't say anything about using the AUDIO controls in this case, only using the MIC GAIN 1 & 2 in the menu (-50/-60 dBu).

So, here are my questions:

1) What is the difference between a "audio component" and a "mic?"

2) If the INPUT switches are set to MIC position, are the AUDIO controls (dials) bypassed, i.e., not used to control recording level?



Hmmm... the term "component audio" I believe comes from audio playback systems that have seperate pieces for, say, CD, tape, tuner, record player, etc. *These have traditionally been connected to each other with line-level signals on RCA phono plugs. *I have to guess that the term used in the manual - "audio components" - may be related to this - such connectors are occasionally referred fo as "component audio". However, what they mean is "line-level audio source". *In general, audio equipment that's designed to be connected to other audio equipment amps its output (when necessary) to line level, which is much less susceptible to noise than mic-level signals.

Mics put out a low-level signal, and as a result, the first "audio component" they tend to be connected to is a preamp (to line-ish level), whether built into some other device or standalone. *The mic/line switch on the DVX basically switches a preamp in or out of the system.

The Audio controls are essential to MIC level recording, and let you fine tune the amplification process to get an optimal line-level signal. They CAN be used with line input as well, but if your line input is good, the middle position of the Audio controls is pretty much what you should use.

I think the -60/-50 issue has two possible connotations. I haven't tested this in detail, but:

often a switched gain is "cleaner" than a variable gain. *So matching the MIC GAIN menu item to the mic can get you closer to your desired level in a cleaner way... then fine-tune with the Audio controls

[xort]

Buy the book 'Producing Great Sound for Digital Video' by Jay Rose.
Well done book that gives you plenty of info.