Recording audio from mixing board XLR

[donna]

Has anyone used the XLR inputs to get the audio from a mixing board? I tried to video a concert last night and the audio was all distorted. I realized afterwards that I had the switch on mic instead of line in. Does anyone have experience with this feature? Will switching it to line in fix the problem? Any other advice. I have another band to tape in a few weeks and don't have the oportunity to practice.

Thanks,
Donna

 

[Huy Vu]

Yes, it needs to be switched to line in. Having it on mic means that the camera preamp is also boosting the signal, causing it to clip even if the level is low.

 

[kenackr]

Donna,

Yes, you can take a line out from the control board to the input of your camcorder when you use the line in inputs on the camera.

However, there is something else you need to be aware of. If this is high energy rock where the sound levels exceed 100db, you may be fine or you may not be.

In larger venues, where every instrument and vocals go through an FOH board, the person mixing is trying to make the levels correct for each instrument. 3 instruments in particular (drums, lead guitar, bass) will usually have higher stage levels than the other instruments, so the person mixing usually has to put less of those individual signals out to the house PA. This normally results in those instruments having lower levels coming out of the board to your camera. That in turn, will have them sounding weak when played back after recording. For vocals, just the opposite happens because other than a stage monitor, there is normally no stage volume and the mixer is pushing the level to get it heard.

Sometimes it works out sort of "OK" and sometimes it doesn't. Just remember that Murphy may be your co-pilot when you don't know it.

If you are doing this for a band to use as a marketing tool and getting paid, the quality of the sound will be very important to represent the band in the best light. If it were me (with 15 years of live sound production & recording) in this case, I would put up 2 good (high level capability >110db) cardioid mics to capture a stereo image and get a realistic sound check to get the gear set up.

You could also use the DVX on board mic if you don't have mics of your own.

If it's just for fun then just go for it any way you like.

Have fun,

Ken

PS- Make sure your audio limiter on the DVX is on!!!!

 

[VGurcu]

Has anyone used the XLR inputs to get the audio from a mixing board? I tried to video a concert last night and the audio was all distorted. I realized afterwards that I had the switch on mic instead of line in. Does anyone have experience with this feature? Will switching it to line in fix the problem? Any other advice.

Forget using the Line-In, %99 it wont prevent distortion from a concert board.
Only solution to your specific need is: Find an XLR(or any other type) master output that has a BOOTH CONTROL dial. Simply turn that control down until the distortion goes away.
TIP: One output that always has a control(Booth) is the HEADPHONE output. Problem is boards usually has only one. If the person in charge of the board allows, you can always buy a 10$ mono splitter and share that output with him/her...
Another important point is always to carry all types of Adapters to take a output from boards. You never know when you are gonna need XLR, RCA or 3/4'' connection. Although you do not mention, I guess you are using wireless mike set If so, also dont forget to adjust the transmitter & receiver controls for distortion preventation.
Another suggestion: Always connect board inputs into a single channel only, and use your on camera (or any other additional mikes) on the other channel. This way if the board sound is bad, you'll still have sound to work with.
Good luck at your next concert...

 

[Alex H.]

Forget using the Line-In, %99 it wont prevent distortion from a concert board.
Only solution to your specific need is: Find an XLR(or any other type) master output that has a BOOTH CONTROL dial. Simply turn that control down until the distortion goes away.

This is wholly untrue. A feed from the FOH console is going to be line-level. Feeding a line-level signal into a mic-level input causes distortion. Period.

And every output on a Front Of House console has a level control of some sort, be it a subgroup fader, aux master pot, etc. You want to snag a board feed that the engineer is not likely to adjust during the show.

TIP: One output that always has a control(Booth) is the HEADPHONE output. Problem is boards usually has only one. If the person in charge of the board allows, you can always buy a 10$ mono splitter and share that output with him/her...
Another important point is always to carry all types of Adapters to take a output from boards. You never know when you are gonna need XLR, RCA or 3/4'' connection. Although you do not mention, I guess you are using wireless mike set If so, also dont forget to adjust the transmitter & receiver controls for distortion preventation.

The headphone out is the last thing that you'd ever want to use. Not only do you have impedence-matching issues there, anything that the FOH engineer might do in the regular course of his/her job will come down that pipe to the camera. I know that the PFL buttons are my best friends when I run FOH... PFL isolates any single input source to the headphones for preview and diagnostic purposes. And if the engineer turns the headphones up or down, there goes your signal level.

An adapter kit is always a good idea. I usually keep things like:

XLR male>male turnarounds
XLR female>female turnarounds
inline (XLR barrel) ground lifts
inline (XLR barrel) pads (both line>mic and selectable attenuation)
XLR>1/4" adapters
XLR>RCA adapters
1/4" couplers
RCA couplers

I've never heard of a 3/4" connection.

Another suggestion: Always connect board inputs into a single channel only, and use your on camera (or any other additional mikes) on the other channel. This way if the board sound is bad, you'll still have sound to work with.
Good luck at your next concert...

Right, but use the on-cam mic only as a last resort. As you move the camera, the sound will change. Best bet is a stand-mounted mic that is then fed to the camera. Mixing the two in post (board feed and room mic) can also compensate for the mix discrepencies that Ken mentioned, since the drums, bass, and guitar will come through the house.

 

[VGurcu]

Hi C2V,
First, thanks for your input... As a videographer/cameraman my preference is to leave the audio recording to a qualified audio person when possible. Reason why I chimed in my suggestion this time is the fact that Donna doesnt seem to have access to an audio person, hence she needed practical advice that helped me many times.

This is wholly untrue. A feed from the FOH console is going to be line-level. Feeding a line-level signal into a mic-level input causes distortion. Period.

I never disputed the fact that console outputs are line-level. I repeat again in different words:
If Donna thinks switching to line-in will prevent audio distortion, she will be disappointed. As Ken explained perfectly, it may, or may not do it. Absloute solution is to reduce the amount of signal going intothe camera's sound board. And booth(thanks for other control names you mentioned)
control will exactly do that job. And when you do that even if you are using mic-level audio WILL NOT be distorted. How do I know? Theory? no, tens of successful recordings I have done over the years...Maybe if I switch the line-in it will help even further, which, i will be testing next time.
So I wont agree with what you are saying about "Feeding a line-level signal into a mic-level input causes distortion. Period." Then my question is, how come I do record high quality audio each time i do this???
Btw, only time i use line-ins are when I have an audio guy helping me (mostly on documentaries & shorts i work on...)

The headphone out is the last thing that you'd ever want to use.

Few times i used headphone outputs i never had any problems, maybe i was lucky, maybe console-person was aware and made sure i received a clean signal. I found the audio quality highly satisfactory, and many times better than using cheap mikes...

I've never heard of a 3/4" connection.

Me neither It is a typo mistake, thanks for correcting it to 1/4''....

 

[Alex H.]

I never disputed the fact that console outputs are line-level.

No, but simply advising to "forget using line in" and assigning it only a 1% chance to help, along with asserting that the ONLY solution to fix this problem was to turn the output from the board way down, are both completely untrue statements. Okay, yes... turning the board feed's signal down considerably can clear up distortion to a point, but I'll explain further down why this still is not the best idea. That aside, you completely dismissed the first step in proper system setup for the audio chain by rejecting the use of line-in.

I repeat again in different words:
If Donna thinks switching to line-in will prevent audio distortion, she will be disappointed.

Of course, there are many other causes of distortion in the signal chain, but matching line-to-line and mic-to-mic is the first prevention and will eradicate many of those other causes.

According to her set-up, switching to line-in will clear up the problem. If it doesn't, it doesn't negate the importance of level-matching. It simply means that there are other factors at play, and we diagnose from there in the knowledge that the distortion is not from improperly-matched signals. Or, perhaps, the mismatched signals were a problem, but were only one part of a compound issue.

As Ken explained perfectly, it may, or may not do it. Absloute solution is to reduce the amount of signal going intothe camera's sound board. And booth(thanks for other control names you mentioned)
control will exactly do that job.

Again, it may not be the single solution if there are other issues, but it eliminates so many other potential problems.

And when you do that even if you are using mic-level audio WILL NOT be distorted. How do I know? Theory? no, tens of successful recordings I have done over the years...Maybe if I switch the line-in it will help even further, which, i will be testing next time.

If you have turned the console output down to where it is barely a blip on the board's meters, you may skirt around most of the distortion. And there might still be some very light distortion there that you've never noticed without a clean copy of the same signal for comparison. But this adds other problems... and maybe your ears have not learned to listen for them.

First, this means that you have to bring up the pre-amps (which are in use with the camera's mic-level inputs) to compensate. And that's poor gain-staging. It adds noise, and using a line-level signal to feed a mic-level input decreases the amount of headroom you have. This will not translate to the camera's meters, but can hose your signal when the meter's say everything's fine. The idea is to feed the input with the properly-matched signal at a properly-calibrated level so that you know the meters on the mixer and the meters on the camera are telling you the same things.

Line-level down an XLR pipe is roughly 60dBv (that's voltage... the level of the electronic signal) stronger than mic-level. That's a huge discrepancy, and the reason that line-level signals can easily, and frequently do, over-modulate mic-level circuits. By turning the line-level output way down, you do compensate for that, but then have to re-amplify the signal, which is redundant at best and noisy at worst. Why redundant? Well, a pre-amp's sole function in life is to bring mic-level signals up to line-level for proper recording. There is no signal that goes to tape at mic-level.

What happens to a photograph when you down-size it, then re-enlarge it? It adds noise, whether you're working in true photography or in digital imaging. Same goes for the audio signal, analog and digital.

I promise you, switching to line-level inputs will help you get an even better signal. How do I know? Over 15 years as a sound engineer in both live venues and TV/film.

So I wont agree with what you are saying about "Feeding a line-level signal into a mic-level input causes distortion. Period." Then my question is, how come I do record high quality audio each time i do this???
Btw, only time i use line-ins are when I have an audio guy helping me (mostly on documentaries & shorts i work on...)

This really comes down to your perspective of "high-quality" audio. Again, there are likely to be artifacts in there that you may not even know to be artifacts, but using line-in with proper gain staging can get you better audio, guaranteed.

Few times i used headphone outputs i never had any problems, maybe i was lucky, maybe console-person was aware and made sure i received a clean signal. I found the audio quality highly satisfactory, and many times better than using cheap mikes...

I never said it wouldn't work. I just said that it is the last resort for getting a board feed. You have been lucky that the engineer has never used PFL (Pre-Fader Listen, aka SOLO), or cranked the level up on you in order to listen closely to the mix. Maybe they've been aware that you have that feed and have avoided using it out of courtesy. I couldn't do that. PFL means too much to me.

There are still volumes worth of other issues to be considered, and perhaps your ear is not trained to hear some of the problems that arise, such as the introduction of noise. Or maybe you've been blessed with consoles that sport über-clean headphone amps.

You may have made this work for you, but without knowing it, you are treading on very thin ice when it comes to the stability of your signal. It sounds like you have been fortunate so far not to have fallen through.

I'm not trying to be a butt-head here. Audio is such an integral piece of any video production, and there's a lot of advice out there that can get folks into trouble. There are also a few simple principles that any shooter should know to survive those days when no recordist is available. You don't have to be a qualified sound engineer to use line-level inputs on the camera, you need only to know your signal source.

 

[Alex H.]

Mods... can we move this?

Mods... can we move this?

Just thinking that this would be much better-served in the audio forum.

 

[VGurcu]

Hi C2V,
It all comes together nicely, thanks again for clearing it. I shouldn't have used terms like "Forget it, only way etc..." After all there is so many things I dont know about sound recording.(And I'll leave it that way so you audio guys can make a living )
This discussion will sure help me to record better audio from a console next time...

 

[TyFord]

C2V pretty much said it all. I'll only add that connectors are just plumbing. You can make no assumptions about what sort of signal is on them. Three pin XLRs can carry mic level, line level, unbalanced stereo (usually -10 but not always) and a few other things.
In general you have low or high impedance, mic or line level (or -10 consumer level), balanced or unbalanced. These are three separate properties. You can pick one from each and there's audio out there like that.

Regards,

Ty Ford