Line In on the XH-A1
 

Is anyone using a field mixer (Sound Devices, PSC, etc.) with their A1? I always try to use line level out of my field mixer but the A1 just doesn't seem to like it - the level is extremely low on my A1 meters. I've got to turn the CH1 & CH2 pots up to MAX to get decent levels, but this just doesn't seem right. I'm nearly certain I've got everything set correctly... "Line" switch set above the XLR jacks, XLR>ON in the menu, Audio Level set to manual. Am I missing something obvious? I can't imagine that everyone is setting their levels to MAX when they use line in from a mixer. I'm thinking the line level my mixers send out is different from the line level the A1 is looking for - does anyone know the details on this? Many thanks!

a1 + mixpre = audio levels?
 

kipjaz-

thank u for raising this important issue. i also want to read any thoughts on using a pre between the mic and recorder.

i have the sound device mixpre but i'm unwilling to purchase an a1 till i know from others how well some of the audio features of the a1 stand up to real world production demands.

be well

rob

First thing came to mind, since you didn't mention it. Maybe you have ATT set on?

Bill

No. the ATT is off, but it only works if the XLRs are set to MIC anyway - it shouldn't have any affect in a line level input.

I think something more fundamental is going on here with the way Canon has set up the line level input. From Googling around a bit about the H1 (which I believe would handle audio the same as the A1) it seems that Canon's line input is looking for a +10db signal. Only trouble is professional field mixers all output a +4db line level! Why on earth Canon would screw this up I cannot fathom. I'm not 100% certain that this explains my problems, but I'm strongly suspecting it. Hopefully someone else here has some more info on this.

Doh! I forgot about that.

The other dumbed down audio design flaws in my opinion are:

There's no selectable auto/manual gain for individual channels & also for the 12dB gain in the menu.

From what I gather, it's the same for all of Canon's cam lineup. I guess users didn't complain, or not enough at least.

Bill

I think you have the answer, Kipjaz, as disappointing as it is (to me at least). The specs in the back of the A1 manual say that line-in is +6dBV which is a tad over +8dBu (pro gear is normally spec'd in dBu). You're right that most pro gear is spec'd for either 0dBu or +4dBu nominally. +8dBu seems oddly high. My SD302 is able to crank up to that level but this will probably be a problem with some mixers. Even with the SD302, you start loosing headroom for the limiters to work. My biggest disappointment with the A1 is the audio design.

-Dan

Well this just seems ridiculous that Canon would design a line level that is incompatible with most every pro field mixer! Sony and Panasonic were able to figure it out, so why on earth would Canon do this? It just makes no sense to me. I'd really love to hear their explanation. Is anyone able to mod the Canon audio to allow for real line level to be input? Someone could probably make some good $$ offering that aftermarket modification.

Ouch!
 

This hurts!

I was ready to buy the A1 for my film group but we'll always be using a mixer - Azden FMX-20 (we had to save money for a good camera!).

the Specs say:

Main Output
+6.5dBu with 600 ohm load 0dBu ref @ 0.775Vrms
+13.5dBu with 1000 ohm load 0dBu ref @ 0.775Vrms

If I understand what you're saying, we'll have to turn the mixer up as far as it will go to get decent levels on the camera - if I've got that right, what the point of having the mixer.

I'm not sure that I understand how this works (no, I take that back - I AM sure I don't understand...)

Hi Paul. Maybe you should try to test if it with your mixer first before rejecting the A1. The line input impedance is spec'd at 10KOhm so your mixer output will be higher than 13.5dBu and it might work out OK.

Richard

Reads more like the Azden FMX 32, not the FMX20, although I believe the +13.5 is +14 dBU for 100K ohms input (essentially an open circuit) on the Azden web site, and that sounds resonable for a 600 ohm ouput impedance.

IMHO the web site specifications for noise and gain for the FMX-20 are not impressive, and my impression is that you may be disappointed if you are looking for high quality, low noise audio.

My quick tests indicate that the XLR line input sensitivity of the A1 is about +6dBV (measured at the A1 input terminals) for "normal" record level (the green dot on the scale). This corresponds to providing 12 dB head room for audio peaks. (This corresponds to about +8.2 dBu.)

But as I understand it, 12 dB head room is typically a consumer and prosumer practice. Profesional audio uses a higher headroom standard, more like 18 to 20 dB. Professional mixers typically are rated for around +4 dBu output, with something like 24 dB or more head room.

Thus you can say the the sensitivity of the A1 for a 'normal' record levels with 12 dB head room is +6 dBV, and if you want 20 dB headroom as with professional recording practice, the sensitivity to achieve normal record level is -2 dBV.

In general, you want as high an input signal as possible to minimize noise contributions of audio amplifies in the chain up to the A/D converters. Remember that every amplifier in a chain not only adds its own self noise to the signal, it amplifies the signal and noise from the earlier amplifiers, including the self-noise of the mic being used.

My impression is that modest cost consumer mic preamps/mixers and perhaps even mics may well have worse noise performance than the A1 internal preamps.

I've used two 24+channel studio mixers with my A1, and I had to turn the line out way up (+6 or more) on all three.

FWIW: Reading the specs on the Mackie mixers (e.g., the 1402), the output for 0 vu indicated on the meter is 0 dBu. This corresponds to about -2 dBV, and thus provides about 20 dB recording headroom on the XH-A1.

Given the relatively low noise level on the Canon XLR input, (especially at line level input where it is more than 86 dB down from max record level) it sounds like a reasonable selection of levels to me.

It was either the Azden or nothing so... maybe down the line we can get a better mixer but right now I need the tools to give young people in the area some experience in the process.

We only have $7,000 left to buy a camera & tripod (that's Aus dollars remember) and the A1 is $5,999 (exactly the same price as the Sony V1)

I still think that the A1 is the better camera, I'm just concerned about the viability of the mixer and the student who's going to be using it.

Are most people using and external mike on a boom connected directly to the camera? if that's the case don't the same problems apply?

I still think I'm missing something (or a lot :-))

Typical mid price range video mics (e.g., NTG-1/2) have a sufficiently high output that the A1 mic preamps should have no problem. The primary issue I see with a mic on a boom is management of cables.

If the mixer output appears to be too low for the line input jack, use its mic level setting (if it has one) or pad it down using a 20 to 30 dB attenuator and use the MIC ATT setting.

Key to understanding all this is to get with someone who speaks audio and understands levels, impedance, etc. to help with selection and set-up.