XL2 Audio ?

[Joe Barker]

I am about to purchase a Canon XL2 but need answers to a couple of questions.I will be filming a documentery using an Audio Tecnica AT-897 shotgun mike.I plan to use a field mixer with headphones plus a mini disk or something similar to record backup audio. Unfortunatly I have been told that unlike the XL1's the new Canon XL2 will only take the mic and not a mixer at the XLR imputs unless I use a pad on the connecters? The sales people know nothing about this,or where I could get such a device.Does anyone have any ideas on this matter,and where I can get these pads ?
Also any suggestions on a good value for money field mixer that would suit my requirements.

[Kelly Wilbur]

Joe,

This "problem" with the XLR inputs just doesn't make sense to me unless you are using a powered (amplified) mixer. If you are using a typical passive mixer, there should be no problem sending the output to the XL2 inputs. What you are doing is essentially just submixing.

The only thing you'll want to do is optimize you levels (mixer output and XL2 input) in order to minimize noise. In other words, you wouldn't want to send a very low signal to the XL2 and have the XL2 gain all the way up.

By the way, there is a 20 db attenuation switch (another word for a "pad") for the XL2 inputs that you'd normally use if signal coming into the mics was too hot.

Thanks,

Kelly

[Jimmy McKenzie]

The difference is that for line in, you must use handle rca inputs in 12 bit mode, where before the XLR in on the the xl1s/xl1 was switchable from LINE to MIC to MIC ATT.

Quite useful was the previous setup when feeding to the cam from a mixer thus avoiding the inherant noise of 12 bit audio ...

[Steve House]

Originally Posted by Joe Barker

I am about to purchase a Canon XL2 but need answers to a couple of questions.I will be filming a documentery using an Audio Tecnica AT-897 shotgun mike.I plan to use a field mixer with headphones plus a mini disk or something similar to record backup audio. Unfortunatly I have been told that unlike the XL1's the new Canon XL2 will only take the mic and not a mixer at the XLR imputs unless I use a pad on the connecters? The sales people know nothing about this,or where I could get such a device.Does anyone have any ideas on this matter,and where I can get these pads ?
Also any suggestions on a good value for money field mixer that would suit my requirements.

IT's true, the XL2 XLR connectors are mic level only with options for a -20db pad or +12db gainup. If your mixer is putting out line level, you'll need to either use the RCA audio inputs or an attentuator to drop the level for the XLR connectors. The line level audio inputs might also require a pad depending on your mixer's output - they're intended for the prosumer -10dBV unbalanced line level standard, mixers can output either -10dBV, +4dBu, or switchable between the two. You might need to put a -6db pad in if you're going from a +4dBu balanced mixer to the -10dBV unbalanced camera (the balanced to unbalanced adds another -6db for a total pad of -12db, the difference between -10dBV and +4dBu).

Shure makes a couple of XLR inline pads, one a fixed -50db and the other switcheable for 3 different amounts of attenuation. Audio Technica also lists one, the AT8202, on their web site.

I'm still in equipment selection mode myself, like you, so I don't have direct experience with them but several of the audio gurus here say very nice things about the Sound Design MixPre, 302, and 442 field mixers.

[Chris Hurd]

Originally Posted by Jimmy McKenzie

you must use handle rca inputs in 12 bit mode

Just a slight correction here; it is in fact quite possible to record via the RCA inputs in 16-bit mode.

[Joe Barker]

Thanks for your advice Kelly,Jimmy,Steve, Chris .This is the sort of information I could not get from the local supplier.

[Don Palomaki]

Also, note that the XL1/XL1s did not have built-in XLR inputs,, just unbalanced inputs. The XLR adapter was an accessory (Canons MA-100/200), or third party. Canon's XLR adapters are powered by the camcorder and limited to MIC level signals, will saturate/clip if the audio input apprached line levels (around -10 dBV).

Some mixers offer an switch controled option for mic level outputs (on the order of -30 dBU), which should be OK.

[Steve House]

Originally Posted by Joe Barker

Thanks for your advice Kelly,Jimmy,Steve, Chris .This is the sort of information I could not get from the local supplier.

My fingers and brain were disconnected - its Sound Devices mixers, not Sound Design.

[Jimmy McKenzie]

Originally Posted by Chris Hurd

Just a slight correction here; it is in fact quite possible to record via the RCA inputs in 16-bit mode.

Yep. True.
I just finished a 2 cam shoot with the board feed 1/4 inch through the handle rcas in 16 bit. No noticeable noise that can sometimes occur in unbalanced audio.
To restate, the ability to run directly in with XLR is preferred but as recent history has shown, the rca unbalanced line in at 16 bit resolution can produce a hum free result when conditions are good.
Thanks Chris ... have fun at DVExpo ... let us know promptly the Canon plans for HDV ....

[Joe Barker]

Thanks again all you guys who provided information , Joe

[Stephanie Wilson]

Originally Posted by Kelly Wilbur

Joe,

This "problem" with the XLR inputs just doesn't make sense to me unless you are using a powered (amplified) mixer. If you are using a typical passive mixer, there should be no problem sending the output to the XL2 inputs. What you are doing is essentially just submixing.

The only thing you'll want to do is optimize you levels (mixer output and XL2 input) in order to minimize noise. In other words, you wouldn't want to send a very low signal to the XL2 and have the XL2 gain all the way up.

By the way, there is a 20 db attenuation switch (another word for a "pad") for the XL2 inputs that you'd normally use if signal coming into the mics was too hot.

Thanks,

Kelly

I'm sorry that I don't know the difference between an amplified or passive mixer. Kelly, I would appreciate your feedback on this point.

Joe, you should be able to select a "mic" or "line" level OUTPUT from your mixer. Check the switches on the output side of you mixer. Choose the 20db switch on the camera if you aren't using a mixer and the audio input levels are too high.

As Kelly said, after you set your master tone level on the mixer, you should set your individual channel output level to 5 on the the mixer and your input level on the camera to 5 and then make slight adjustments on both when needed.

I bought a Shure SHA15LA attenuater that cuts 50 db at B&H for $39. I am a one woman "band" and need this when I take a board feed without the benefit of a sound person with a mixer.

Best wishes,

Stephanie

[Kelly Wilbur]

Originally Posted by Stephanie Wilson

I'm sorry that I don't know the difference between an amplified or passive mixer. Kelly, I would appreciate your feedback on this point.

An amplified mixer is one with an integrated amplifier. I'm almost positive no one is using one of those. They are used to drive PA speakers. A passive mixer does not have an amplifier and essentially only drives a signal at a line level (-10 or +4).

Thanks,

Kelly

[Steve House]

Originally Posted by Kelly Wilbur

An amplified mixer is one with an integrated amplifier. I'm almost positive no one is using one of those. They are used to drive PA speakers. A passive mixer does not have an amplifier and essentially only drives a signal at a line level (-10 or +4).

Thanks,

Kelly

But what you are calling a "passive mixer" still has gain in that many take a very low mic level input and output a line level at -10dbV or +4dBU. Some field mixers like the SD 302 have a switchable output that can be set to either mic level or line level but most are line level only. This is way too hot for the Canon's mic level XLR connectors or any other mic level input without further attenuation.

I'm wondering if some of the audio gurus could chime in and answer a related question I've been curious about - if you were using something like the 302 to feed a camera's mic input, which would be the better practice, to set the mixer output to mic level with the cable between the two carrying the mic level signal or to keep it at line level and insert a pad just before the camera to drop it down so that the cable between the two carried line level signals? Or perhaps phrased another way, if you were using a line level mixer to feed a mic level camera, would it be better to attentuate at the mixer end of the cable or the camera end? (Assuming balanced throughout.) I would expect the latter would give better noise immunity but I wonder if that's really true and if it would be signifigant. In the same vein, the Canon has a switchable 20 db attenuator on the input. If you figured you needed a 50 db pad, for instance, would you do it with the internal attentuator switched out and put a full 50 db attenuator in the line or would it be better to switch the internal attentuator in and add another 30 to the inbound line? Or is it likely to matter?

[David Ennis]

To an electronics tech, "passive" means no amplification. If it consumes power from any source, it ain't passive. A "Y" connector would be an example of a passive mixer.

Regarding attenuation placement, or the amplitude of the signal over the most of the length of the run, in my humble technical estimation there can be a difference, but it is not likely to be significant in balanced runs.

Induced noise, as we know is cancelled. Noise developed in resistors and connectors becomes part of the signal, and its percentage is constant before and after the signal is stepped down. That all says, "no difference."

But at the points where resisitive and/or contact noise is generated, that's not linear. Higher voltages will dilute at least resistive noise. I'm not so sure about contact noise, that's a fluky phenomenon.

So if human life or the freedom of my grandchildren were at stake, I'd go for higher signal level over the run. That being said ('cause obviously I like to talk and I have summers off), like you I'd defer to the voice of experience.