CX550/560 Audio (Auto adjust?)

[Mark Chafe]

Hello,

I recently purchased a CX550 and a CX560 for some 2 camera interviews I will be doing. I understand that there are very little audio controls and metering on these cameras, however I did not know of the camera's auto adjust for the audio. It seems that both the "normal" and "low" audioref setting tries to correct the audio coming in from the external mic input and adjust it to its own level rather than taking the true audio level.

I would like to take the audio out of my mixer and feed it into the mic input of the CX550 and CX560 for editing purposes, but knowing that the camera does what it wants to do with the audio this may not be an option. Is there a way to turn this off or another work around? I don't really want to have to record audio to a separate recorder then have to sync it up in post.

Would a mic/line attenuation cable help or something else? I would like to keep the camera since I have tried others in the price range and find this one the best, except for the audio.

Thanks
Mark

[Eric Olson]

Originally Posted by Mark Chafe

Would a mic/line attenuation cable help or something else?

Since the 1/8" microphone input of the CX550 has plug in power you will need 10uF capacitor to block the DC bias as well as an attenuating circuit. A simple schematic is

                 C1
+Line level in --||----R1----+-- +Mic level output
                   +         |
                             |
                  +----R2----+
                  |
Ground (input)----+--------------- Ground (output)


R2 = 1 kohm
R1 = 10 kohm
C1 = 10 uF

http://www.epanorama.net/circuits/line_to_mic.html

[Mark Chafe]

Can these cables be purchased already made? And if so, would this disable the auto correction of the audio signal? I have done a little research since and found that juiced link makes a box to disable the auto gain control on some dslr. Would this be the same thing?

Thanks
Mark

[Jim Stamos]

you need to buy a studio one xlr adaptor to attach to the bottom of the camera . you plug their mini plug into mic jack and use a wireless or wired lav into this. the audio is pristine.
studio1productions.com or studiooneproductions.com, not sure

[Jay West]

Mark: the answer to your question depends on what kind of signal you are getting from the mixer that you mentioned using. I'm flying blind here since you did not describe the mixer. Also, it is not clear to me if your concern is with signal level or with the audio-auto-gain-control in the cameras.

So I will take a scattergun approach here.

First, do you know if your mixer is outputting mic-level or line level signals? Are you taking your audio feed from "record out" jacks? Those will be line level and will overpower the mic input on the CX cams.
AFAIK, my CX550v will only accept a mic-level audio input when in camera mode.

Maybe you have a mixer that allows you to switch the output level from line level to mic level? (My 16 channel Mackie does this but smaller mixers might not have this.) If you have not checked that, it may help a lot. Basically, if your mixer is putting out a line level signal, it will be too hot for either of the CX cams' two "micref" settings.

It would be even worse if you have a DJ or party-type mixer which have a power-amp that is designed to feed some small loudspeakers.

If the problem is too-hot a signal from a line level feed, you can buy off-the shelf attenuators. I believe DVinfor sponsor B&H carries some as do the likes of Radio Shack. I tried some of these things a decade or so ago, but the signals were not always clean and some units developed a hum after a while. There may be better off-the-shelf units out there.

The Studio One XLR adapter unit that Jim suggested might be a better option because they are pretty durable and they have their own volume controls. (Similar, devices are also sold by Beachtek, Signvideo and Juiced Link) These small, passive mixers that allow you to take line-level and mic-level inputs (including XLR feeds) out to a 1/8th" mini-stereo jack for input into a video camera. They will attenuate line level signals to mic levels. They have a separate volume control for each channel which is something that a plain attenuator will not have. I have units from both Signvideo and Studio One which I have been using for years. I often use them in place of my more cumbersome 16-channel Mackie mixer. Also, the Mackie needs external power to operate wheras the XLR adapters do not.

If you get one of the XLR adapters, you will have to experiment to see when to you get better results with the "low" and the "standard" micref settings in the CX cam's menus. My personal experience is that it varies with the venue and program I am recording. For wedding speeches and toasts, I've generally run with the standard setting. For wedding dances, bands, dance recitals (where I have my CX cams at the edge of a stage) and concert recordings, I generally have had better luck running on the "low" setting.

On the other hand, if you are looking for some way around audio-auto-gain control with the CX cams, I know of no external devices that will defeat the on-camera audio AGC operations in a CX cam. About all I have ever been able to accomplish is to tweak the settings on an external mixer to the point where he signal does not trigger the on-camera audio-AGC very much and then fiddle with audio tracks using Sound Forge or Audition to mitigate the worst aspects of AGC.

[Eric Olson]

Originally Posted by Mark Chafe

I have done a little research since and found that juiced link makes a box to disable the auto gain control on some dslr. Would this be the same thing?

Attenuating cables and circuits like the one described in my previous post will not disable the automatic gain control in the microphone input. The trick that Juiced Link uses to disable automatic gain on a DSLR should also work with the CX550 but I've not tried it. Since you are already running a mixer for the sound, have you thought about using a separate audio recorder?

http://www.bhphotovideo.com/c/product/757065-REG/Tascam_DR_05_DR_05_Portable_Handheld_Digital.html

[Jay West]

A separate audio recorder will give you more control and may yield cleaner audio but there are always trade-offs. You will have to work on syncing with your video. Plural Eyes software can be very helpful in getting the initial synch for you but it does not (AFAIK) deal with clock drift. Since external recorders work off clocks that can vary (sometimes significantly) from camera clocks, you have to be vigilant in checking the synch as you edit. Depending on the external recorder, there may or may not be much work for this kind of work. The other trade-off is that you have one additional device to watch over. Depending on what and how you shoot your videos, this may or may not be a big problem. (I regularly run mutli-cam shoots where I have had as many as seven cameras running, so having one more recorder running does not seem like a big deal to me as long as it can be fire and forget.)

Like Eric, I do not have a Juiced Link device so I do not know if its DSLR circuits will also over-ride audio-AGC on the CS cams. I recall reading something about it being specific to DSLRs, but that very well may have been innacurate. I suggest you e-mail the company and ask. Also, a numberr of DVinfo sponsors sell the units and might be able to tell you with a phone call if the AGC override works with CX cams.

[Mark Chafe]

Thanks very much for the replies.

The mixer I was trying to take audio out of was a Mackie ProFX 8. It does not have microphone level outputs. I was able to adjust the level to bring it down to where it wasnt being distorted in the camera, however there was still noticeable hum.

I may consider bringing the CX550 and CX560 back and get something with more manual controls such as the Canon Vixia HF S20 and use a Studio 1 xlr. I do like the picture and interface of the Sony, but if getting an external audio interface for the Sony is still having me battle with the AGC I may be better off with the Canon. I really don't want to have an external recorder for audio or something $400+ for something that may disable the AGC.

One question for Jay West, you said you used a Studio 1 Productions XLR pack on the CX550 alternating between "low" and "normal" settings for the micref level. How much issues did you have with the AGC?

Thanks
Mark

[Ron Evans]

I think the AGC is a compressor/ limiter so that if the level is below the threshold it has no effect this level is set by the menu item based on how load the source is going to be. The hum is from the DC bias on the input that supplies power to Sony condenser mics intended to plug into the input. Most of the adapters will block the DC bias and also have line inputs so you could use one of these . I have this one XLR Adapter XLR-BP PRO XLR Adapter For Camcorders and Video Cameras that works well for me. You will still need to find the setting that works best. Might be worth a try for the price and would also work for any other camera you got too.

Ron Evans

[Jay West]

I second what Ron said. I also have one of those same units. If you get hum, you just flick a a toggle switch on the adapter to block the DC bias and the hum goes away. That said, I once worked with somebody else's Mackie that produced a hum of its own. My recollection was that the unit was plugged into an incorrectly polarized socket, but the unit itself may have been defective. My solution at the time was to skip the mixer and run two mikes to one camera and the other two to another camera.

Also, Mark, the XLR adapters allow you to record a line-level stereo feed to left and right channels or record a mono source (single mic) to both channels. For a feed from your Mackie 8, you will need either RCA-to-1/8" adapter plugs (if using RCA outs from the mixer) or 1/4"to1/8" adapters (if using 1/4" jacks). They are very inexpensive. If the Mackie has XLR outs, you just plug them into the XLR inputs on the adapter.

Originally Posted by Mark Chafe

One question for Jay West, you said you used a Studio 1 Productions XLR pack on the CX550 alternating between "low" and "normal" settings for the micref level. How much issues did you have with the AGC?
Mark

Not much.

For your 2-camera interviews, there should be no problem. When you use an XLR adapter, you probably will not need to use the "low" micref setting on the CX cams

I use the CX cam's low settings for the steadily loud, very noisy conditions like those I mentioned. Mainly, this is to avoid clipping with very rapid jumps in sound level. With other situations, I leave the sound level on standard because I find I get less noise during quiet passages. Mostly, where I've run into difficulties with AGC has been when taping musical theater. There can be sudden and very sharp transitions from full-on loud singing to very quiet dialog and back again. This can produce audio "pumping" which I fix in post. Interviews should not have this kind of problem.

[Eric Olson]

Originally Posted by Mark Chafe

such as the Canon Vixia HF S20

The Canon HF500/400 models also have manual audio levels, a line-level input setting, better picture quality and may be cheaper. If you stick with the CX550, the circuit I mentioned above should take care of the hum. Moreover, the cost of building a stereo version of this circuit would be less than $20.

[Jay West]

I cannot say whether the picture quality of the Canons is any better or worse than the video quality from the Sony CX cams, but the price of a new HFM500 is slightly more than the price of what a used CX550v was going for the last time I looked. Like the CX cams, the Canon has a separate headphone jacks, which seems important for what Mark wants to do. The Canon has the ability to manually control the audio input level, although that may or may not matter to Mark. If the Canon actually has a line-level switch for the mic input (as opposed to the A/V socket), that could be a plus. You would still need an XLR adapter if you want to plug in XLR mics.

[Mark Chafe]

Thanks for all the info. I wish I had figured out the audio options on these cameras before I bought them. Luckily I was able to return them. I liked the Sony picture and definitely the interface much better than the Canon cameras I have used, however the audio options are not what I would like to have. I understand going from a prosumer to a consumer camera, there are things I would have to do without, however I need manual adjustment of audio. I do not mind if it is line or mic level input as I was going to have to buy an xlr - minijack box eventually, but the audio AGC is a big no no, and the lack of meters or the lack of proper meters in the case of the cx560 and similar is not doable for me. I know there are external options I can use, however the less devices I need the better.

Right now, there seems to be some Sony Vixia HF S## series camcorders coming at a resonable price range for me. The HF S10 / S20 and S30 right now. I am leaning towards the S 20 and 30 a little more as they have LANC control another option that is almost a requirement for me (at least on one of the cameras). I would need a pair of similar cameras at least for shooting interviews mostly. Or would the HF M50 / M500 cameras be something better to look at. I notice it does not have a manual control wheel which I think I would miss.

Again many thanks.
Mark

[Ron Evans]

You may want to ask on the Canon forum for input on these as the specs show them also to have automatic audio attenuators so could be just like the Sony's. Moving to the Canon XA10 would give you complete control but is more expensive of course.

Ron Evans

[Eric Olson]

Originally Posted by Jay West

I cannot say whether the picture quality of the Canons is any better or worse than the video quality from the Sony CX cams

I meant that the Canon HFM400/500 has a better picture quality than the HFS20/30. The 8.5MP sensor used in the HFS30 is prone to aliasing and noisy in low light, but the HFM400/500 camcorders should have a picture quality at least as good as the Sony CX cams.