Resolved Question

Canon Vixia HF-G40 "Audio Mix"

When mixing audio from the Canon Vixia HF-G40's camera mic with audio from an external mic plugged into its 3.5mm audio terminal, via the camera's "Audio Mix" setting, which of the two is happening?:
a) both mics' audio are mixed and recorded so that both mics record on the video's Left audio channel and both mics record on the Right audio channels.
b) the 2 mics' audio are separated where only one goes to the Left audio channel, and the other mic goes to the Right audio channel

If the answer is a), then is there some other way with this camera to separate the 2 mics' audio onto Left and Right channels?


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Reply to: Canon Vixia HF-G40 "Audio Mix"
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Best Answer

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This may be late, but I ran a test

I wanted to know the answer to the same question and since I have a G40 I tried it. In the "Audio Mix" function you are setting the mix level between the two inputs, external mic and internal mics. Both inputs will be recorded to both the left and right channels at the mixed levels you set. BOTH inputs will be on BOTH channels with no way to alter the recorded mix. Not optimal since changing and monitoring the levels can be difficult while recording in many situations.

Please Canon, could a firmware update split these out and record the internal input to one channel and external input to the other? I need to be able to control the mix of the levels in post, not in a noisy environment while I’m recording. Thanks.

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Finally! Someone who chose to just answer the question....

...instead of discussing barely related topics. Thanks for answering!

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Great answer and test.

It's just as suspected by the sparse doc in this area. To really nail the audio, we have to, like so many other systems, get the audio rigged like a pro. More mics and recorders then pull it together in post.

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Documentation does not write it will be purely L and R
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Yep, I read that, too, and all I found is the same thing ...

that you found; and yes, you're right, that what we read does not mean I can't test it; however, not having the camera does mean I can't test it. That's why I'm asking if anyone knows the answer to my question, not whether or not I could run tests to determine the answer.
Thanks much for your reply!

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It has to be tested to tell if it's good enough.

the fact the 2 mics are close to each other is going to have some mixing. If you want true isolated audio you'll have to get professional with another audio recorder. My son's degree was in film with an audio engineer direction so he's very much in the know on this. For his shoots there are a few other recorders on the set. Then it's all brought together in post production.

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What 2 mics are you saying will be close to each other?...

What are you saying has to be tested to tell if it's good enough? And good enough for what?

When you say "true isolated audio", are you meaning each microphone's audio isolated to 2 separate audio tracks? If so, are you saying that that isolation requires using another audio recorder because you know that the HF-G40 does not allow that separation?

Does your audio-trained son (or anyone else reading this) happen to know about how this camera's "audio mix" function works and thus can answer the question I asked in my original post?

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Good enough for you.

I can't guess why you need this but can relate to it because of my son's studies.

As to true isolated it's a way of writing that what the left mic hears does not show on the right channel. Given the proximity of the mics I have to write there is a 99.99% chance something will bleed over.

As to my son, they don't own that model so no.

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What is it that are you saying has to be tested to tell...

..... if it's good enough for me? And in what respect are you referring to a determination if that thing is good enough for me?

What mics are you saying you have to write, given their proximity? And what does it mean to write mics?

What is this "something" you are saying there is a 99.99% chance of bleeding over? From what would this "something" bleed, and to what/where?

If your son doesn't own the HF-G40 camera, and doesn't know about what my original post asked about that camera, how is that he is, "very much in the know on this", as you said in your earlier post?


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I fear you are a bit lost.

In your top post you asked about more than one mic so mics to me is the plural form.

Since you question how to donate more than one of a thing either you are lost in all this or dare I say trolling.

As to in the know, you appear to posit that if we don't own the one model that we aren't in the know. That's quite the narrow view.

As such I have to write good luck in your searches. Call the maker and have a talk with them about what you want to know.

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Don't be afraid. I am not lost. You are correct, I am ....

..... referring to multiple/plural mics, as I so clearly articulated in my original post - 2 mics, to be exact (as I mentioned in my original post).

Why do you refer to me donating something, when I never made any reference to or suggestion of such a thing?

Why do you say I posit that you aren't in the know, when it is you who said that your son doesn't know about what my original post asked because he doesn't own that camera. I did not state a view there, that was you stating your view that your son doesn't know.

I don't know why you keep mentioning unrelated things to my question, and not directly answering most of my very specific questions. If you're doing this for a laugh, then ha-ha, good one, you got me - you've successfully wasted lots of my time.
If English is not your first language, and what I've been saying is difficult to comprehend, let me know, and maybe I can re-phrase the question. Otherwise, please just look at my original post, and try to answer that. All you have to do is answer "a", "b" or "I don't know". Anything else you say is not an answer to my question.

If anyone reading this thread can please just read my original post and answer it directly, I'd appreciate it.


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Spelling correction error. Try denote.

Replace donate with denote and that's what I meant. Sorry for not catching my spelling error there.

I have answers but not authoritative ones. That is, from using dozens of camcorders and what my son's major was I can offer commentary about how to ask the maker and what I've seen or rather heard so far in real life (IRL to some.)

So I did answer, then I became worried since you asked "what does it mean to write mics?" This to me means you may not be chatting with folk a lot about the topic or you demand no shorthand. That is, you want folk to write "microphone" and "microphones."

I don't mind that but had hoped that you would make that pre-sales call and use what my son and I have learned over the years.

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"Denote" means, "be a sign of; indicate", so if I replace...

.... your "donate" with "denote", it is as if you wrote, "Since you question how to indicate more than one of a thing either you are lost in all this or dare I say trolling."
With that in mind, I ask you what indication of more than one of a thing it is you think I'm questioning?
All I asked is if the answer to my original post is a) or b). The only time and forum/thread space anyone has to consume to answer my question is the very very very short answer "a", "b", or "I don't know". Any one of those answers would take all of a couple seconds to do.

You say you have non-authoritative answers. Why would someone ask a question and want an answer that is non-authoritative? ALL a questioner would want is an authoritative (correct) answer. I'm not here looking for someone to start a slightly nonsensical conversation that appears at first glance to be somewhat loosely related to what I asked about.

Why do you keep mentioning your son's studies?
You're telling me that based upon the existence of your son's related studies, and based on your experience using camcorders, that you advise me to contact the camera manufacturer for the answer to my questions?
Well, you may find it interesting and maybe helpful to know that someone without those studies or experience is just as able to suggest to someone to contact the manufacturer.
The whole point of this forum is as a replacement or supplement to contacting the manufacturer.

What does "IRL" mean?

You say you "did answer", but you didn't say which of my many questions you're saying you answered. I also don't see anywhere that you answered my original question, which, again, would only require an "a", "b" or "I don't know". Where is this answer of yours that you're referring to? What was it?

As you correctly stated, I did ask, "what does it mean to write mics?"; however, you replied with a suggestion that I don't want the use of "mics", instead of addressing and actually answering my actual question about what "to write mics" means.
This demonstrates that you either missed, misunderstood, forgot and/or ignored the multiple times I used the word "mic" or "mics" in my original post/question. My multiple use of that word clearly demonstrates I understand what "mic" means. Your suggestion of me not wanting the use of "mics" is, at best, inept and misleading, and at worst, disingenuous and makes any reader question your motive for replying to this thread.
SO - are you going to answer about what "to write mics" means? Or answer any other questions about your ambiguous and/or non-sensical answers you've put on this thread?
How about skip all that, and just do as I've suggested/requested several times now, and just answer my original question with an "a", "b" or "I don't know"?


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PS. There's always a call to the maker.

If they won't discuss their products, that's a bad sign. Here I don't mind looking up what is documented but in this case only the test will tell if it's good enough.

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Sorry if I missed something here, but does your reply....

....address my original question?


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Just a WAG...

But I'd try putting it through Audacity.

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What do "WAG" and "Dafydd" mean? Also, what is it you're....

....saying you'd put through Audacity, and why would you do that?


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Mixing the mics

I would suggest that logically the left mic signals go to the left channel and the right mic signals go to the right channel. This would be so unless you have an instruction in "Audio Mix" to alter this.
The problem is that the camera mics are so close together that sound intended for the right channel will also be heard by the left channel so cross mixing can occur.

If you need good stereo separation then I suggest you use external mics. My example is that I use a Tascam recorder that will both support two condenser mics (phantom power 48V) and provide a stereo connection to my camera's external mic socket. So I achieve a good stereo recording from mics that can be separated by a good 20ft and also record the same signal on to the video track in the camera. I then sync the good recording to the audio on the video track in my video editor and scrap the audio track connected to the video.

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I understand your logic-based suggestion, but that ....

..... doesn't apply to my original post/question, as there are no left or right mic signals involved.

Why do you say the problem has to do with the camera mics' proximity to each other, when that has nothing to do with what I asked about?

I appreciate your suggestion for stereo separation, but that is not related to what I asked about in my original question/post.
Why do you suggest I use external mics, when my original post/question already so clearly states that that is what I'm asking about?

So, do you happen to know the answer to my original question/post? (Hint: the answer you could/should reply with would either be "a", "b" or "I don't know")


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a) both mics' audio are mixed and recorded so that both mics record on the video's Left audio channel and both mics record on the Right audio channels.
doesn't apply to my original post/question, as there are no left or right mic signals involved
Pity you don't understand stereo. Of course there is a left channel and a right channel. How do you think a stereo signal is produced?
b) the 2 mics' audio are separated where only one goes to the Left audio channel, and the other mic goes to the Right audio channel[/I
Which is what I suggested happened in your case.
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I appreciate your sympathy, but no need to pity me, as ....

... I've been successfully understanding (and field mixing, recording, editing and output mixing) stereo (as well as mono, dual channel mono, etc) for some 25 years now. Understanding stereo is definitely not an issue here.

You are correct in saying "Of course there is a left channel and a right channel.", but just like most, if not every, reply on this thread so far, that is irrelevant.

You said in your latest post that you had previously suggested that option b) applies to my case, when in actuality, you had not suggested that. What you did say is, "I would suggest that logically the left mic signals go to the left channel and the right mic signals go to the right channel.", which is clearly not the same thing as what I wrote in option b).
Do you truly not understand the difference between the configuration you suggested, and the configuration I described in option b), or are you just giving me a hard time?

If you're just trying to give me a hard time, and you and your friends are getting a nice chuckle behind the scenes by talking nonsense, then kudos to you - you got me!
BUT, if you're trying to be helpful, then I suggest you guide your pity toward yourself, and anyone else who lacks the ability to understand what I wrote and/or the ability reply with something relevant or applicable.

Here's a Pro Tip for ya: Go back and read what I wrote, and pay attention this time. You're in the general ballpark in your understanding, as you are correct that we're talking about mics and audio channels, but beyond that, you haven't yet demonstrated understanding of what I wrote.

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Canon HF G40 Audio Mix of 2 chanel recordings

Solution for this topic is next HF G40 has two mod for recording sound:,
1) when there is no external mic camera is recording sound to one channel,
2) when there is external mic we have two possibilities depending on quality of video recordings
- When the recording mode is set to 28 Mbps LPCM (59.94P) or 24 Mbps LPCM for AVCHD movies or when recording MP4 movies, recordings will be made with 2ch sound
- in all other cases sound will be recorded on one channel and in this case you can use audio mix giving priority to camera mic or external mic.

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Back Up Recorder is Still a Must

My 2 cents- I am delivering low bitrate MP4 files from the G40 to be sent via e-mails.
I was trying to avoid lengthy post production times, as delivery is within a day or so.
Running times- 4-6 hrs.
Looking ahead, I dreaded one of 2 channels w/ 2 mics failing, buzzing out, etc.
I was disappointed I couldn't just delete or manipulate one channel . Then I realized the G40 is
a prosumer cam, so for the price, I can't complain too much.
A back up independent recorder is the way to go. If by chance there wasn't one--
I tried to experiment by using Adobe CS6 Audio Audition, creating duplicate clips,
panning one way over to Right. Chan and the other way over to the Left ( volume
adjustment per your ailment- intermittent static, bomb going off in the neighborhood, etc.).
then creating 2 independent audio files for editing.
If mics are not too close together, it may work to mitigate some buzz, static,
other disasters.

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