XLR jack / Audio questions at DVinfo.net

Dil Singh · September 1st, 2009, 03:14 PM

Hello to dvinfo.net Folks,

I needs some help. I will be recording a live stage show this weekend. For audio, I am planning to connect a long cable to one of the XLR terminals in the back of my XL H1A and connect the other end to the sound system. My question is, does it matter what the length of the cable (maximum) is? To get stereo audio, do I need to connect to CH1 and CH2 XLR jacks? What is the best way to do this?

Thanks in advance for help.

Oren Arieli · September 1st, 2009, 04:33 PM

The shorter the better. You can run 100ft (some might tell you 200ft), but keep in mind that these cables are easy to trip over, so unless you can run them hidden or taped down, I would be very careful. I've also run into a problem where longer cable runs act like antennas and pick up local radio stations (even shielded cables). You will need 2 XLRs for stereo. You'll need to talk with a sound engineer if you want to get a clean feed. Leave plenty of extra time for setup/taping down cables.
My advice, use a portable solid-state recorder and sync in post. The Zoom H4 and others allow you to plug in XLR or 1/4 inch and record stereo without having to bust out the long cables.

Dil Singh · September 1st, 2009, 05:19 PM

Oren,

That is a great tip. But my problem with solid state audio recorder is that, if the show runs for 3 hours straight, I will have to stop the recording on the camera several times, at least 2 or 3 times just to change the tape, then the audio will be out of sync and I know that it will be a nightmare to sync in post.

Thanks.

Garrett Low · September 1st, 2009, 11:15 PM

Dil,

Syncing in post is not that hard. If you go duel systems no matter what you will be syncing in post because the audio will drift from the video.

I do several live shows a year that run anywhere from 2 to 3 hours. I take audio into my cameras via mics through a mixer then out to each camera. That is my backup audio. My main audio for mix is from my mics I set up as well as from the board feeding me area mics, stage mics, main talent mics etc. I usually have up to 8 channels that I record into my laptop. Then in post I mix the sound for best results. The audio drift to when I use this set up is very noticeable and can be up to 10 frames after an hour. It is not consistent though.

For smaller setups where I only need stereo recording I have also used my Sony D-50. I take the mics out of my mixer and into the D-50. That actually yields some really impressive quality. I've done piano recitals using this or small quartets and the sound is very impressive especially if I capture at 24bit, 128k (extreme overkill but if you can do it why not). For my Sony the drift is extremely predicable at 3 frames every hour.

To sync I just use the waveform of the camera and the other audio signals.

Two reasons I don't just take the camera audio. The first is that usually, the sound engineer is mixing for the house. So, the sound the cameras are picking up isn't necessarily the best or sometimes even good when reproduced via DVD etc. Second, since you're shooting HDV the audio that is picked up is compressed. I find that any post work to the audio is somewhat challenging when you start with the compressed signal.

As far as cable lengths I try to limit it to 50ft runs but have used up to 100ft. No matter what I always tape down cables just to be safe.

BTW, I also shoot with an XL H1A and an XH A1 as my second camera.

Paul R Johnson · September 2nd, 2009, 04:44 AM

Mixer line level at low impedance won't be a problem for cable length. The usual comments based on physics indicate you'll lose a little HF, but in practice, with decent cable, it's not worth worrying about. If the choice was 100m of mic cable or an RF system, I'd go cable every time.

The only downside to cable is when you trip up, catch the cable on something, or somebody pulls it leading to a very fast pan!

Dil Singh · September 2nd, 2009, 12:21 PM

Thanks guys. I am impressed with the help I get every time from DV Info members.

Dave Gosley · September 3rd, 2009, 02:24 AM

Cable would be best - and to avoid the cable trip up scenario pay someone a few sheckles to enjoy the concert with you by spotting for you - that is cable managing behind you - making sure you neither run out or walk over the cable.

If you study behind the scenes footage in studios it is quite common place to have at least one person making sure the camera has cable when it needs it, and that it's tidied up and out of the way when its not.

It'll never be perfect but you're less likely to get tied in knots halfway through.

If using cable I always wear a sturdy leather belt and loop the audio cable around the belt before taking it to the camera. This way around if the cable gets a tug the audio cable does not put a direct pull on the sockets / camera which is likely to do damage. This means your body will take the pull - some don't like it as you are tehered to strongly which is where I introduce an emergency snatch escape - that is a balanced male and female jack a couple of feet down the cable after it's left the belt. Better to lose sound for a few seconds than do massive damage to the camera that you can't immediately recover from and with the snatch breaking contact with the camera should someone trip on it you are better of losing the sound than facing a massive insurance bill beause someone has tripped on your cable and knocked their teeth out - even if they were drunk at the time.

If the cable parts company with you there'll be little chance of damage other than a few seconds lost audio.

September 1st, 2009, 03:14 PM	#1
Dil Singh New Boot Join Date: Mar 2009 Location: California Posts: 16	XLR jack / Audio questions Hello to dvinfo.net Folks, I needs some help. I will be recording a live stage show this weekend. For audio, I am planning to connect a long cable to one of the XLR terminals in the back of my XL H1A and connect the other end to the sound system. My question is, does it matter what the length of the cable (maximum) is? To get stereo audio, do I need to connect to CH1 and CH2 XLR jacks? What is the best way to do this? Thanks in advance for help.

September 3rd, 2009, 02:24 AM	#7
Dave Gosley Major Player Join Date: Oct 2007 Location: Hampshire Posts: 226	Cable would be best - and to avoid the cable trip up scenario pay someone a few sheckles to enjoy the concert with you by spotting for you - that is cable managing behind you - making sure you neither run out or walk over the cable. If you study behind the scenes footage in studios it is quite common place to have at least one person making sure the camera has cable when it needs it, and that it's tidied up and out of the way when its not. It'll never be perfect but you're less likely to get tied in knots halfway through. If using cable I always wear a sturdy leather belt and loop the audio cable around the belt before taking it to the camera. This way around if the cable gets a tug the audio cable does not put a direct pull on the sockets / camera which is likely to do damage. This means your body will take the pull - some don't like it as you are tehered to strongly which is where I introduce an emergency snatch escape - that is a balanced male and female jack a couple of feet down the cable after it's left the belt. Better to lose sound for a few seconds than do massive damage to the camera that you can't immediately recover from and with the snatch breaking contact with the camera should someone trip on it you are better of losing the sound than facing a massive insurance bill beause someone has tripped on your cable and knocked their teeth out - even if they were drunk at the time. If the cable parts company with you there'll be little chance of damage other than a few seconds lost audio. __________________ http://www.videoproductionshampshire.co.uk

September 1st, 2009, 04:33 PM	#2
Oren Arieli Major Player Join Date: May 2007 Location: San Jose, California Posts: 918	The shorter the better. You can run 100ft (some might tell you 200ft), but keep in mind that these cables are easy to trip over, so unless you can run them hidden or taped down, I would be very careful. I've also run into a problem where longer cable runs act like antennas and pick up local radio stations (even shielded cables). You will need 2 XLRs for stereo. You'll need to talk with a sound engineer if you want to get a clean feed. Leave plenty of extra time for setup/taping down cables. My advice, use a portable solid-state recorder and sync in post. The Zoom H4 and others allow you to plug in XLR or 1/4 inch and record stereo without having to bust out the long cables.

September 1st, 2009, 05:19 PM	#3
Dil Singh New Boot Join Date: Mar 2009 Location: California Posts: 16	Oren, That is a great tip. But my problem with solid state audio recorder is that, if the show runs for 3 hours straight, I will have to stop the recording on the camera several times, at least 2 or 3 times just to change the tape, then the audio will be out of sync and I know that it will be a nightmare to sync in post. Thanks.

September 1st, 2009, 11:15 PM	#4
Garrett Low Trustee Join Date: Jul 2007 Location: Novato, CA Posts: 1,774	Dil, Syncing in post is not that hard. If you go duel systems no matter what you will be syncing in post because the audio will drift from the video. I do several live shows a year that run anywhere from 2 to 3 hours. I take audio into my cameras via mics through a mixer then out to each camera. That is my backup audio. My main audio for mix is from my mics I set up as well as from the board feeding me area mics, stage mics, main talent mics etc. I usually have up to 8 channels that I record into my laptop. Then in post I mix the sound for best results. The audio drift to when I use this set up is very noticeable and can be up to 10 frames after an hour. It is not consistent though. For smaller setups where I only need stereo recording I have also used my Sony D-50. I take the mics out of my mixer and into the D-50. That actually yields some really impressive quality. I've done piano recitals using this or small quartets and the sound is very impressive especially if I capture at 24bit, 128k (extreme overkill but if you can do it why not). For my Sony the drift is extremely predicable at 3 frames every hour. To sync I just use the waveform of the camera and the other audio signals. Two reasons I don't just take the camera audio. The first is that usually, the sound engineer is mixing for the house. So, the sound the cameras are picking up isn't necessarily the best or sometimes even good when reproduced via DVD etc. Second, since you're shooting HDV the audio that is picked up is compressed. I find that any post work to the audio is somewhat challenging when you start with the compressed signal. As far as cable lengths I try to limit it to 50ft runs but have used up to 100ft. No matter what I always tape down cables just to be safe. BTW, I also shoot with an XL H1A and an XH A1 as my second camera.

September 2nd, 2009, 04:44 AM	#5
Paul R Johnson Inner Circle Join Date: Nov 2005 Location: Lowestoft - UK Posts: 4,016	Mixer line level at low impedance won't be a problem for cable length. The usual comments based on physics indicate you'll lose a little HF, but in practice, with decent cable, it's not worth worrying about. If the choice was 100m of mic cable or an RF system, I'd go cable every time. The only downside to cable is when you trip up, catch the cable on something, or somebody pulls it leading to a very fast pan!

September 2nd, 2009, 12:21 PM	#6
Dil Singh New Boot Join Date: Mar 2009 Location: California Posts: 16	Thanks guys. I am impressed with the help I get every time from DV Info members.