AC90: AC-90 has no auto mode for XLR inputs??

C

ChrisHarding

Well-known member
Hi Guys

In the AC-90 manual it states that unlike the 130/160 you have no manual/auto switch on the XLR channels but you can have the internal mic only in full auto where levels are looked after my the camera. The XLR channels seem to have ALC but am I right in saying that they just handle the audio if it peaks too much ?? If you use an XLR input, you still need to set the audio level with the control and, if needed, adjust it during shooting...If so, my concern at wedding receptions is that the music level varies greatly from song to song so one would probably need to ride the control almost constantly as the mic is facing the DJ speakers sometimes and away from them other times.

Maybe Barry can confirm that a mic connected to either XLR input has no full auto level control like the HMC40/80 used to have....If so it will make filming wedding receptions really tough. Is there a way around this?

Chris
 
The XLR inputs do not have any sort of automatic level control. They have a limiter, but not level control.

If you are using one mic, and you want to "protect" against sound being too loud in some circumstances, typically what you would do is plug the mic into XLR 2, then assign both channels to take their input from channel 2, then set one level for "normal" and set the other channel quite a bit quieter. That way you'd use the "normal" channel for most of your audio, but if things got too loud you could go to the backup channel which, having been set to a lower level, should not be clipping.
 
I suppose the negatives to using a standalone audio recorder and then synching using PluralEyes, are that 1) you have to drag the unit around as the venues change 2) you might have to adjust the volume and the unit will typically be a lot less reachable compared to the on-camera volume adjustments. I continue to have problems with the lack of fine control over volume when I get an XLR feed - the operators at the sound board often play around with the volume so I am constantly having to watch for peaking (or too low a signal). Then, as and when I try to adjust it with the little dials, a couple of notches up/down makes a big change to the volume. The solution of course is to bring your own mixer but this does not work for one-trick-ponies like me. Same problems with lighting. I suppose this is why they invented 'crews'.
 
Last edited:
Thanks Barry

That's a fairly standard trick and should get one of of trouble when audio varies a lot and you might forget to change it...I don't think it's too big a deal at weddings as when radio mics are plugged in I'm full manual anyway .it's only getting a bit of footage on the dance floor ..I left my cam in manual with a live band once and the audio was unusable. The clarification is appreciated.

Walter? I only use a DVR as a backup as I prefer to be able to monitor my audio in real time.. at weddings putting my Tascam DR-05 on the altar with a boundary mic often helps with priests that wander around the Church..doing your sort of shoots should be really simple ...maybe a couple of mics in front of the group?

Chris
 
Hi Barry,

I've been following your comments since the 'first look' thread. Thanks for all your insights - I'm a real newbie, have just bought the AC-90 as my first 'decent' camera (my previous camera was a pana 3ccd domestic range camera, mini DV, the NVGS300 I think, about 7 years old ... so the AC90 is a big step up for me).

One of the big reasons I upgraded was that sound quality was so poor in my old camera (vision wasn't superb, obviously, but was reasonable compared to audio). When I bought the AC-90 I also bought a rode ntg-1, so I should be able achieve MUCH better results.

Anyhow, I broke the cardinal rule, and the first time I took the ac-90/ntg-1 out was for my daughters piano recital (I knew I shouldnt do it, but I figured that on iA on the AC-90 I would get a better result than from my old camera). The result was great vision wise, but the audio picked up alot of background hum. I figured maybe the ntg-1 was 'too good' and over sensitive .. and then through some forum posts and reading the manual more closely, I worked out that I had the camera set to 5.1, which from what I can now work out, means I wasn't actually using the ntg-1, I was using the ac-90s on board mic?

So, sorry to be a newbie pain, but can you give me some more tips on how to achieve what you described above with the 2 channel thing, break it down a little please?

Also, did I read somewhere that you would be bringing out a book? If so, will this be available in Australia, or online somewhere?

Thanks very much.

Todd in Western Australia
 
Hi Todd

A fellow enthusiast in WA ..that's great!! I'm in Perth. All Barry is saying is plug your mic into XLR 2 not XLR 1 but on the panel switch Channel 1 so it feeds channel 2 ..that way you have two channels (like a left and right) on the finished clip and in your NLE you can use the left or the right, whichever sounds better. Basically set your level controls so Channel 2 gives a nice strong signal at around -6db and make sure it doesn't go into the red ..then set Channel 1 a bit lower (typically around -12db) so if your levels do go over you have the option of using the slightly softer channel as an alternative..... The NG1 AFAIK is a phantom powered mic so phantom power (panny usually mark it as +48v) must also be on. If you are using the Rode cables then you certainly shouldn't be getting any hum at all!!

Chris
 
Just a note on hum, Todd. Your audio gain settings on the camera are not going to help out with that. Barry's suggestion is to help CYA for situations in which you might be recording too hot and clipping your mic signal.

Just need to get that shotgun mic closer to your subject.

You might try popping a set of ipod headphones onto your camera so that you'll be more aware of when you are not getting sound you'll be happy with.

Did anyone make a quality audio recording of the recital that you can use for an audio track for on your video cut?
 
If I may respectfully add, on my NTG-1, I played with the roll-off switch located on the mic. itself. I had too much bass thus a somewhat muffled sound.
 
Sorry guys, real newbie stuff I know (first camera with XLR inputs and/or 2 channel options), but could someone please really break it down for me - stp by step. eg plug the ntg-1 into xlr-2 ... but then how do i set channel 1 (int(l), input1 or input 2) and how do I set channel 2 (int(r) or input2)? Sorry, I know this demostrates a basic lack of understanding!

Also, just to further help me understand (and maybe the answer will become apparent with the settings), but how come we couldnt achieve the same thing by using input 1?

Finally, once I've done this (and then used the ch1 and ch2 control dials to roll one back on -12db) I guess that when I transfer footage/audio to my PC, there will be 2 seperate audio channels?


Thanks for the guidance, and sorry for the ignorance.

Thanks also to bluesgeek (will I find you around the Gibson Forum, and/or Blues Guitar Unleashed forum also?) and Lou. Luckily I was able to clean up the audio from the recital with a soundgate I use on Vegas Pro, so the end result was still much better than what I would have got with my old camera!
 
Todd, set channel 1 and channel 2 to input 2. Now both channels are taking the same signal (the external mic). (You can't do the same with input 1 because you can't set channel 2 to input 1.)

In your NLE you will have two audio channels on the clips, and if you've set your gain as per Chris' spec, you should see that the levels are different. Now you have the option of using the lower channel if the higher channel clips.

My first email account in 1994 was bluesgeek @. Decades ago I used to post on the old listserves as bluesgeek, and still use it around the tech forums, but no longer hang with the musicians, since in 2011 I traded one low-paying creative career for another!
 
Thanks for that - in fact, given the time difference by the time you'd posted I'd actually managed to work it out, but was good to have the confirmation - andI learnt a valuable lesson: never try to work these things out by just reading the manual, or posts - always do it with your camera in your hands!
 
Just one follow up about Barry's settings - the ac90 sets a 'mic' input at -50db, and a 'line' in at 0db. Should I be setting my 'normal' channel at 0db by turning up the gain on the camera, and leave the 'low' channel at the -50db? or is the normal channel -50db and i wind back the low one even further with the dial?
 
It is quite interesting how when I re-read comments some thing new sinks in. I never thought of just using one mic with 2 channels one being -6db lower than the other. I was so pleased with the built-ins (compared to a few other built-ins I've used) I was using a built-in as a back up. On my NTG2 my own very limited listening tests were giving me better results with the -60db setting.

I don't have much experience with noise and pre-amps on many other cameras, but I have heard clearly audible the noise from a Marantz hand held recorder when I did a film challenge on the big screen and it was embarrassing. The Marantz is better spec wise than the Zoom H4N so that part surprised me, but I am not sure if the editor did any noise cancellation/reduction/filtering when she was editing. My own question is how good are some of the included noise filters with FCP/FCPX/Adobe at addressing noise and something that I am running into with a friends cheap Azden wireless is it is giving me hum (I am pretty sure its due to it being an unbalanced 3.5mm connector) and whether using it on a H4N would help enough or should/would buying a $60 http://www.fullcompass.com/product/240134.html dual channel transformer/isolator for maybe a one time use (5 sentences of dialog).
 
Todd_Sh said:
Just one follow up about Barry's settings - the ac90 sets a 'mic' input at -50db, and a 'line' in at 0db. Should I be setting my 'normal' channel at 0db by turning up the gain on the camera, and leave the 'low' channel at the -50db? or is the normal channel -50db and i wind back the low one even further with the dial?
Click to expand...
I don't think you are looking at a 0db unless you have a line (mixer) feed in. I would assume you have both at -50db and the gain setting you adjust with the dial and watching the meter on the LCD. Set one channel at -6db and the 2nd at -12db. As my test on the NTG2 I would go with the -60db. Also page 60 of the manual shows the -12db to be at the mark on the LED. -6db would be half way between that and max (0). If you have the ALC on you won't generally see anything hitting the 0.
 
You must log in or register to reply here.
Back
Top