Boom mic into xl2 - rca line or xlr for cleanest audio input? at DVinfo.net

Lonnie Bell · July 29th, 2006, 11:55 AM

Hello all,
I'm aware i can't use the included stereo mic and a seperate source into the xl2 and maintain 16bit, due to the on-board stereo mic hogging two channels...

so, i'm disconnecting the stereo mic and will be booming an akg blue line series (ck-98) mic into the xl2 - so for the cleanest sound - questions are? (Job is a corporate dvd - talking head, possibly noisy BG)

1. use xlr input or rca line (i don't have a preamp or mixer)?
2. i know i can make a stereo pair from a mono-recording in post, but is there a cleaner acquisition - record 16 bit stereo or mono?
3. if you're familiar with my akg (ck-98,-91), any camera or mic settings you'd recommend (atten, filters, etc...)?

thank you in advance,
Lonnie

Jarrod Whaley · July 29th, 2006, 01:41 PM

So wait, you're just using the one AKG mic? If so, I'm not sure what the issue is.

XLR will be better than RCA 100% of the time.

Lonnie Bell · July 29th, 2006, 02:38 PM

well, it's my understanding that the built in preamps are sometimes better (circuits are quieter) in the line in versus the mic xlr in (as i believe was the case with the xl1s versus the ma100)...
and the xl2 went through major improvements, and i'm just not sure... and by the time the mic is shipped to me, i won't have a lot of time for testing prior to the gig, so any experience would be appreciated...

Jarrod Whaley · July 29th, 2006, 02:55 PM

It's worth noting that the ma-100 converts a balanced XLR signal to either 1/8" phono or RCA, because the XL1 doesn't have built-in XLR jacks like the XL2 does. So in either scenario with the XL1, you're using the RCA jacks.

Because the XLR connections in the XL2 are grounded and the RCA jacks are not, you are most definitely going to get much less noise with the XLR's. What's more, if you're using an XLR-capable mic with the XL2's RCA jacks, then you're replicating the exact same situation as with the Xl1/ma-100 combination.

All of this is why XLR's are built-in on the XL2 in the first place. Use 'em.

Allan Beecroft · July 29th, 2006, 03:45 PM

Further to Jarrod's comments, I'm not sure what length of cable you plan on running from the boom mic to the camcorder and in what type of environment etc but XLR connections and their associated circuitry are the more professional choice (as you will see in just about every professional audio set up).

One of the reasons that XLR can be a better choice is that they are low impedance balanced lines and less susceptible to noise. Basically, any noise picked up from nearby equipment (mains hum and RF etc) is induced on the cable as common mode. As it is low impedance, it has an easier path to ground via the shield of the cable. If it gets passed the shielding, it ends up as common mode noise on both the hot and return lines which gets cancelled out at the pre-amps. With RCA, you're more prone to picking up noise. Think of it this way, you have a long strecth of wire from source to destination which basically acts as an antenna, prone to picking up external electrical signals.

Therefore, because of the low impedance, you can have a lot longer run of cable before any induced noise becomes significant. Unbalance RCA lines are acceptable up to a point but if you're working in an environment with lots of other electrical/electronic equipment about, you would be better of with XLR.

I use both RCA and XLR depending upon the audio quality I need, the environment I'm shooting in and ease of set up. Overall, I'd say I use XLR 95% of the time.

Just some other areas to consider :-)

Allan

Greg Boston · July 29th, 2006, 04:23 PM

Quote:

Originally Posted by Lonnie Bell

1. use xlr input or rca line (i don't have a preamp or mixer)?

Yes you do if you have an XL2. The pre-amps are not too shabby on the camera and your mixer is the two knobs that control audio levels on the camera's left side. You'll also need phantom power if using a condenser mic which the XL2 supplies. Just make sure the little 'ATT' swtich on the back neasr the +48 isn't turned on. It's backwards, in that 'on' is the down position. I had mine set wrong at first and by the time I cranked the audio input to get an acceptable level, I had all kinds of noise. Once I got it set correctly and re-positioned the audio level knob, it was fine. I recorded some ambient room levels and they came out to be -54db.

-gb-

Lonnie Bell · July 29th, 2006, 10:59 PM

you are all gents - thanks,
Lonnie

July 29th, 2006, 11:55 AM	#1
Lonnie Bell Major Player Join Date: Mar 2006 Location: Las Vegas, NV United States Posts: 361	Boom mic into xl2 - rca line or xlr for cleanest audio input? Hello all, I'm aware i can't use the included stereo mic and a seperate source into the xl2 and maintain 16bit, due to the on-board stereo mic hogging two channels... so, i'm disconnecting the stereo mic and will be booming an akg blue line series (ck-98) mic into the xl2 - so for the cleanest sound - questions are? (Job is a corporate dvd - talking head, possibly noisy BG) 1. use xlr input or rca line (i don't have a preamp or mixer)? 2. i know i can make a stereo pair from a mono-recording in post, but is there a cleaner acquisition - record 16 bit stereo or mono? 3. if you're familiar with my akg (ck-98,-91), any camera or mic settings you'd recommend (atten, filters, etc...)? thank you in advance, Lonnie __________________ Lonnie Bell mamas boy productions Las Vegas, NV

July 29th, 2006, 01:41 PM	#2
Jarrod Whaley Major Player Join Date: Jun 2006 Location: chattanooga, tn Posts: 721	So wait, you're just using the one AKG mic? If so, I'm not sure what the issue is. XLR will be better than RCA 100% of the time. __________________ -->jarrod whaley. www.oakstreetfilms.com

July 29th, 2006, 02:38 PM	#3
Lonnie Bell Major Player Join Date: Mar 2006 Location: Las Vegas, NV United States Posts: 361	well, it's my understanding that the built in preamps are sometimes better (circuits are quieter) in the line in versus the mic xlr in (as i believe was the case with the xl1s versus the ma100)... and the xl2 went through major improvements, and i'm just not sure... and by the time the mic is shipped to me, i won't have a lot of time for testing prior to the gig, so any experience would be appreciated... __________________ Lonnie Bell mamas boy productions Las Vegas, NV

July 29th, 2006, 02:55 PM	#4
Jarrod Whaley Major Player Join Date: Jun 2006 Location: chattanooga, tn Posts: 721	It's worth noting that the ma-100 converts a balanced XLR signal to either 1/8" phono or RCA, because the XL1 doesn't have built-in XLR jacks like the XL2 does. So in either scenario with the XL1, you're using the RCA jacks. Because the XLR connections in the XL2 are grounded and the RCA jacks are not, you are most definitely going to get much less noise with the XLR's. What's more, if you're using an XLR-capable mic with the XL2's RCA jacks, then you're replicating the exact same situation as with the Xl1/ma-100 combination. All of this is why XLR's are built-in on the XL2 in the first place. Use 'em. __________________ -->jarrod whaley. www.oakstreetfilms.com

July 29th, 2006, 10:59 PM	#7
Lonnie Bell Major Player Join Date: Mar 2006 Location: Las Vegas, NV United States Posts: 361	you are all gents - thanks, Lonnie __________________ Lonnie Bell mamas boy productions Las Vegas, NV

July 29th, 2006, 03:45 PM	#5
Allan Beecroft New Boot Join Date: Jul 2006 Location: Livermore, CA Posts: 22	Further to Jarrod's comments, I'm not sure what length of cable you plan on running from the boom mic to the camcorder and in what type of environment etc but XLR connections and their associated circuitry are the more professional choice (as you will see in just about every professional audio set up). One of the reasons that XLR can be a better choice is that they are low impedance balanced lines and less susceptible to noise. Basically, any noise picked up from nearby equipment (mains hum and RF etc) is induced on the cable as common mode. As it is low impedance, it has an easier path to ground via the shield of the cable. If it gets passed the shielding, it ends up as common mode noise on both the hot and return lines which gets cancelled out at the pre-amps. With RCA, you're more prone to picking up noise. Think of it this way, you have a long strecth of wire from source to destination which basically acts as an antenna, prone to picking up external electrical signals. Therefore, because of the low impedance, you can have a lot longer run of cable before any induced noise becomes significant. Unbalance RCA lines are acceptable up to a point but if you're working in an environment with lots of other electrical/electronic equipment about, you would be better of with XLR. I use both RCA and XLR depending upon the audio quality I need, the environment I'm shooting in and ease of set up. Overall, I'd say I use XLR 95% of the time. Just some other areas to consider :-) Allan