MA-100 XLR audio adapter questions

[Vic Owen]

Yeah, the Beachtek units are great--I have one that I used on my Sony D-8. I've been tempted to get the one for the Canon.

I messed up a shoot discovering the problem with using the MA-100. During later troubleshooting, I "teed" the cables into the XL-1 so I could hang an oscilloscope on the cords--I was amazed at how little it took to get into limit. Live and learn.....

The MA-100 works great with mikes, but quite often I either use my Mackie, or take a feed of the house board.

Yep, the Sierra is a great little bird--we'll have to chat sometime. I manage the air traffic systems at Sea-Tac. Been kind of a zoo since 9/11 -- especially for the VFR stuff in the Class B airspace.

Cheers, Vic

[Ed Frazier]

Hi Vic,

I've been following this thread with interest since much of my audio comes from either my 1402 or a house board. I don't have a scope to analyze the signal (or would know what to look for) so have to rely on my ears, but here are my subjective test results.

Mackie Setup (audio signal from CD player):

CD line out connected to 1402 Channels 1 & 2 line in with RCA to 1/4" cables
Channel trims adjusted per Mackie instructions (very important step according to Mackie)
Ch1 panned full left
Ch2 panned full right
Both Channel Faders set to Unity Gain
Main Mix out set to Unity Gain
XLR Main out set at +4 and connected to MA200
Tape Out RCAs connected to XL1S Audio 2 RCA inputs
1402 leds hovering around 0 and peaking at +7 (no yellows)

XL1S/MA200 Setup:

Audio set to 12 bit St1-St2
Audio 1 set to line level and receiving input from MA200 XLRs
Audio 2 set to line level and receiving input directly from 1402 Tape Out RCA jacks
AGC was set to both Auto and Manual settings during test
Audio was monitored with headphones at camera

Results:

Using the audio select button on the XL1S, I switched between Audio 1 and 2 with the only noticable difference being a slightly brighter sound on Audio 1. Switching both Audio 1 and 2 to Manual mode, I was able to get the same levels on the XL1S meter with the manual level controls set just slightly above mid point. XL1S meter peaking at -2.

I noticed no apparent distortion or clipping on either Audio 1 or 2 with the above settings.

My question is; Should I be able to hear the "hard limit" condition that you describe? I did push the 1402 Main Mix above Unity Gain and did begin to notice some distortion on the XLR (Audio 1) input, more so than on Audio 2, but Mackie does warn that levels above +7 will likely distort. It doesn't sound like you were anywhere near that though. Since I'm using the MA200 is it likely that Canon made some changes to correct the condition you describe?

Thanks,
Ed Frazier

[Vic Owen]

Ed,

Good write-up describing your set-up. It sounds like the MA-200 might be responding a little differently than the 100. When the output LEDs on my Mackie hit the half-way point to "0" (-4 or so), the MA-100 will start to limit. The Mackie output looks good all the way up to the yellow LED, so it's not the mixer. I can feed a "hotter" signal directly to the XL-1 using an unbalanced cable, and not experience any distortion.

Part of this problem lies in what I'm shooting -- live theater typically has massive level changes, e.g., quiet dialog punctuated with yells, screams, applause, accompanists that think they're the "show", etc. With a sound guy on top of the situation, it would be easier to manage, but I'm busy enough just dealing with just the major contrast changes that occur from the lights.

If the MA-100 was a passive device, like the Beachtek or Studio One, this likely wouldn't occur. And, as I mentioned earlier, I'm also probably not using the MA-100 as intended, since with mikes it's works great (minus the phantom power, though).

I'd like to play around with the MA-200 sometime--it appears to be a 100 on steroids! And, maybe the active components have greater dynamic range.

Sounds like your set-up works for you--I wouldn't change it based on my experience.

Cheers, Vic

[Ozzie Alfonso]

Vic,

I'm curious about one aspect of your setup. Using unbalanced and usually unshielded cables are prone to two things - hum from any AC line crossing the cables and cable length limitations. What are you doing to minimize any or both of these problems? I can't predict how far from the XL-1 the sound guy will be but it will usually not be more than 30 to 50 feet. But there will invariably be any number of AC sources along the way.

[Ed Frazier]

Well Guys, I should have done more testing before posting my last. While the audio sounded good, when loaded into Premeire the clipped amplitude on audio 1 was very apparent even with the limited waveform displayed there.

The solution, at least with the small Mackie mixers, is set the output to "mic" level and you can still use balanced lines. I did another quick test with the same setup as described above but with the mixer XLR main out set to mic level. I changed audio 1 input level to mic and again compared the waveforms in Premeire. They were identical.

So with that said, it looks like the MA100 and MA200 behave exactly the same, and as you said Vic, are designed for mic level inputs only.

Thanks for pointing that out.

Ed Frazier

[Vic Owen]

These boards, set-up by Chris, are amazingly active! I wish I'd discovered them before--great stuff!

Ed, I think it's all manageable, once you're aware of the limitations. A crew helps, but I'm a small operation, so the budget has its limitations. Maybe, when I retire from the FAA, I can get "big".....Ha! Glad this was a good heads-up for you.

Ozzie, you're right about the unbalanced line--I'm only using 10' and I'm real careful about the AC cords for the camera, etc. Much longer than that I'd prefer to use the balanced XLR, thus the need for the Beachtek or equiv.

Experimentation in a quiet environment helped me a lot, but I'm sure you've been there many times before.

I've also enjoyed your responses on this board--it's comforting to know that even the "pros" ask questions.

Cheers, Vic

[Ozzie Alfonso]

>>it's comforting to know that even the "pros" ask questions<<

Pros are asking questions because it's a rapidly changing world and we need to keep up. Just this morning I had a chat with my business partner -- "Who will we hire to work the XL1?" he asked. "No one. I'm working the camera." "You'll get burned out. We're shooting for twelve days." What he really meant, besides burning out, was 'you're not a camera operator... not really' " Well, I am a camera operator who's been a director for too long. Besides, where will we find an operator that has spent the holidays on this board getting great advice from everyone? I doubt any of our usual sound people will know about the M100 problem. It's too specific a problem.

The "system" is geared for your standard big crew -- i.e. Director; Camera/DP; AC; Sound mixer; sound assist; Art Director; Key grip; 2 grips; AD; PA; script; and a gaggle of PAs. As budgets go down we need to keep production quality up. Among other things, the crew is being reduced to - Director/camera/DP; AC; Grip; script; PA.

We're in an interesting situation - "consumer" became "prosumer" and now the "pros" are turning "prosumer" to just "pro". The quality coming out of 3 chip cameras is almost as good as any BetaSP if shot with care. The manufacturers keep the cost down by not supplying SMPTE time code and SMPTE bars. They also need to protect their professional division from the consumer division. But the pros need to keep pushing the envelope. As a result we now have a hires view finder for the XL1 and better optics. Canon, Panasonic and Sony are very responsive to market demands. It's people like us in this board that need to keep raising the bar. After all it wasn't ordinary consumers that created the demand for a hires viewfinder.

The same thing is happening in the post field. We have three Avids in operation. The oldest one cost us $80,000 and became obsolete (hardware and software) within two years. The newer Avids cost us a bundle and their proprietary codexes drive us nuts. Along comes Apple with Final Cut Pro. I saw the first version at a convention years ago and I thought it was "interesting" but not for us "pros." Well, now we have Final Cut Pro v3 that rivals Avid in most respects and costs less than $1000! AND it can run on any G4 or iMac! (Avid will support only the exact system it sells you. Add anything and support is gone.) FC Pro also has a compression scheme that allows up to 40 minutes of material in just one gig! I can off-line a feature in my Powerbook! The question now is - where will we find a good Final Pro editor? Most of the good Avid editors were good film editors before that. They just had to learn the system. Why not learn another, simpler, system? Editing is editing no matter what the system.

All this boggles the mind. When I first started editing it was in a room with two Quad playback VTRs and one record Quad. That was three operators plus me - the AD/Editor. It was noisy and each VTR cost upwards of $150,000. The 2" tape stock cost about $90 for a 60 min reel. I'm not even mentioning how much it cost for the three operators and a maintenance engineer.

My reply is a bit long-winded I'm afraid. I'm just very happy for the kind of people that visit this board. It's not an overstatement to say it's places like DViCommunity that are disseminating the type of information and fostering the enthusiasm that's changing the way the industry does business. Just when we thought we knew it all, there's a whole new challenge. Great!

[Ozzie Alfonso]

Vic,

I've been talking with a sound guy who's done a good deal of sound work with MiniDV. His suggestion is to RF the signal from the mixer to a receiver on the XL-1 and then go directly into the Beachteck (or M100 if it accepts line input which it doesn't). This sounds like the best way to get around the unshielded cable problem. I still will monitor the sound off the XL1's headset output.

[Don Palomaki]

My tests indicate that the MA-100 will start to clip if the input signal (voltage applied between pins 2 and 3 of the XLR jack) goes above about -7 dBV.

Allowing for headroom, it sould be uised with mic level signals. In the case of typical mixers, use the mic (e.g., -30 dBV) output setting.

In many environments a -30 dBV balanced signal at 600 ohms will be a better audio signal choice than -10 dBV unbalanced at 47 k ohms.

[Vic Owen]

That's good additional info--I never put an audio level meter on the input, only observed the output with an o-scope.

I suppose it's all "doable" with the MA-100, but I've gotten gun-shy after getting nailed during a one-time shoot. (I wish my ears were as accurate as the scope.)

Maybe I need Ozzie's sound guy.......!

Vic

I just received the MA-100 and Sennheiser ME66 mic with K6 power supply. I bought a 15' XLR cable from Radio Shack and put them all together and it did not work. It didn't work whether I disconnected the onboard mic or not.

Please help!

Update---

I put up the volume and checked all the settings and made sure the Menu settings had MIC on it also - It works on Audio 1 only and it is very very low. The onboard mic that came with the camera is 30x louder than my ME66 connected to the MA-100!

Any ideas on this problem? I'm going to need to use it very soon!

[Ed Frazier]

Be sure you set the Input Select switch behind the audio controls door on the left side of the camera to Audio 1. Also, be sure the MA-100 power is plugged into the DC out terminal and the RCA connectors from the MA-100 are plugged into the Audio 1 terminals, not Audio 2. Set Audio 1 Record Level if you are not using AGC.

Check the battery in the K6 and make sure the power switch is on.

When the Input Select switch is in the Audio 1 position, the onboard mic is disconnected so it will make no difference whether it is connected or not.

You have probably already checked all this but it wouldn't hurt to go over all the settings again. You have most likely just overlooked something.

Ed Frazier

[Vic Owen]

It sounds like you've checked to make sure the Audio One IN menu is in MIC, not LINE or ATT 20, and that you have Audio 1 selected. I also presume you've checked both channels. So....

I'd suggest either going to a camera store that carries mics, or one where they sell musical instruments, and either trying another mic, or trying your mike on one of the store mixers -- most musical instrument stores have a Mackie or something similar set up, and usually have lots of various mics.

I haven't used the Senn -- does it require phantom power other than the K6?

I know that 'panic feeling.....best of luck.

Vic

I believe I got it to work - Thanks for your help.

But the onboard mike still sounds louder than my ME66. I have to speak directly into the ME66 to hear it. Maybe it's because of my cheap headphones? But I hear the onboard one fine.

This is important because I'm filming durning Carnaval next month in Trinidad and I want to be sure I'm picking up the sounds of the crowd and all. I'm planning on purchasing the lightwave equalizer windscreen.

Any thoughts?

[Vic Owen]

The on-board Mic on the XL-1 is an amazing device and I'm always amazed at its pickup. I've used both Peavey super- cardioid and Shure PZM mics and they both sound pretty good without having the sound source right on top of the mic. It might do you well to compare to some others. It doesn't sound like a headphone issue to me. In my experience, the Canon mic is slightly louder than the externals, but not dramatically so. Keep in mind, though, that the Senn is more of a shotgun pattern than the Canon -- that might make a little difference, but it shouldn't make a lot.

Vic