XH-A1 Audio Limiter

[Ben Hillier]

Does this cam have an audio Limiter? I have searched, but seem to get conflicting information as to whether this cam has an audio limiter.
Does it have one in manual mode, not just auto gain mode???

[Benjamin Hill]

It has a -20dB attenuator (not a limiter) and it is a switch on the XLR input housing.

[Ivan Mosny]

There is no audio limiter in XHA1.

[Robert Phillips]

Would using auto level control serve for your purposes? Using it does limit the signal but at the cost of having a variable gain during recording. Very useful if your "actors change their volume during takes). On my last shoot I had one subject who whispered during sound checks and shouted during takes.

[Allan Black]

Are you sure there's no limiter on the A1?

For a while I thought there wasn't one on the HV20, no mention at all in the manual. But there is and its great.

[Bill Pryor]

The only limiter is if you use auto gain.

[Jack Walker]

I just reviewed the manual and checked the XH-A1 in real life.

Yes, the XH-A1 is like the PD150/170, and the auto switch turns on a limiter. And that's all it does (see page 49 in the English manual).

Then, the in-built mic sensitivity can be adjusted (see page 47 in the English manual). If using the XLR inpusts, the input level of the mic can be controlled with the ATTenuator switch or with in-line attenuators, or with a mixer.

The auto mode simply limits any peaks that are too hot for legal audio, and the input level must be controlled.

The XH-A1 does not "pump" the level up and down like a consumer auto-gain camera does.

(As a side note, the PD150 has cleaner sound on auto and a good input than on manual. I don't know if this is true with the XH-A1, but it does seem to be true that using a mixer and feeding a line level to the camera will give better audio.)

To check your XH-A1, first turn the camera on manual audio, then watch as you can raise and lower the input by twisting the dials. At a good level, the meter will hover around the green dot. When the signal is clipping the red dot will light.

Then turn the switch to auto (A). Notice that the dials have no effect. Put the camera in front of a TV. Watch the meter as you raise and lower the volume on the TV. If the TV is loud the meter will be high. If the TV is low, the meter will stay low. However, no matter how high you turn the volume on the TV, the red dot will not light, because the limiter is knocking down the peaks.

However, limiters also have limits, so it may be possible to get distortion on auto if the sound is too high, but I don't know.

[Bill Busby]

The only thing is... it affects both channels. Say you have 2 mic sources, one wireless, one cam mounted shotgun, with the wireless as your primary. Point the A1 to a louder sound source & the level for the wireless will diminish & sound compressed. This is one reason it irks me that the manual/auto switch wasn't designed for separate channels. What's the logic behind this design :-\

Bill

[Ben Hillier]

Interesting replies that get me thinking a little. I have an HV20 and want to introduce a for flexible camera to my system and the A1 is the obvious choice. I mainly shoot doc style oftem alone, no sound man. For this reason limiters seem paramount. On the Hv20 I always shoot manual audio to avoid sound going up and down BUT I have to constantly worry if its going to distort because there is only a limiter in Auto. I was hoping the A1 would avoid this problem but Im not so shure. One user sais the Auto Gain doesn't ride to much the volumes - do people agree with this?

[Benjamin Hill]

I disagree. I use the XH cameras for documentary work, mostly one-man and the auto settings for audio are the next best thing to having a dedicated sound op. With the design and layout of the audio controls on that camera, it's nearly impossible to ride the levels manually and get solid usable audio. I only use manual for interviews and such where there won't be too many variables, and even then I keep a close eye on the levels.

[Don Palomaki]

This is one reason it irks me that the manual/auto switch wasn't designed for separate channels. What's the logic behind this design :-\

The logic of having the auto gain mode effect both audio channels equally is to preserve the stereo image (relative positioning of sources).

Folks may recall that the early PD150s had a significant audio preamp noise problem that Sony eventually fixed during the production run, and they offered a retro-fit for early PD150 models. But if I recall correctly, the VX2000 owners were out of luck.

[Bill Busby]

Originally Posted by Don Palomaki

The logic of having the auto gain mode effect both audio channels equally is to preserve the stereo image (relative positioning of sources).

Don, that makes no sense to me. If an opposite channel gets suddenly hit with a loud audio source & it affects the other "isolated" channel to the point where that channel's levels are so compressed it's basically useless at this point, how is that preserving a stereo image? I'd rather have that control in post if need be.

How many other semi-pro/pro cameras combine both channels for auto gain? I can't think of any. And the reference to the pd150 is a different issue altogether. In fact, even the pd150 has separate auto/manual switches for each channel :))

Bill

[Don Palomaki]

Bill, because the amplification in the channels remain the same relative to each other (i.e., both change by equal amounts) the relative loudness of a give sound in one channel compared to the loudness of the same sound in the other channel remains unchanged. This results in the sound's left/right positioning in the stereo image remaining the same.

This is akin to changing the master volume control on an amplifier. On the other hand, allowing AGC to effect one channel only would be akin to change the balance control on an amplifier.

With an independent signal to each channel (not stereo program material), independent AGC makes sense, but with stereo program material it does not make sense. Given that the Canons ship with a stereo mic, their default makes sense. Having the ability to go either way would be nice, but would add a bit to the price and probably confuse folks moving up from a consumer camcorder. And many pros claim they never use audio AGC so it would be a waste on them.

As a note on the evolution of Audio on the X* line, the original XL1 had Volume and Balance controls on the Audio1 channels (not individual channel level controls as it had on the Audio2 inputs).

[Allan Black]

Yep. So we're back to adding a good mixer with limiters for 2 separate audio tracks.

[Don Palomaki]

Add external mixer and limiters if you need to do so for what you are recording.

FWIW: for what I shoot (mainly a mix of events on the run and live performances), I've not found that to be necessary. A mixer with line level output, and the low noise floor of the A1 can all but eliminate the need for a limiter for most situations. (But it is unlikely that any two randomly selected people will have exactly the same audio requirements.)

Thats what I love about all this, lots of opportunity to try new and different toys. Anyone doing money shoots is well served by spending a bit of time in advance testing their kit under field conditions to satisfy themselves as to its performance and their ability to manage the gear in the field.