Excellent question!

The beach teck adapter will let you spec line or mic. Also, it has a 1/8 jack pass through for wireless, etc.

MA-300...blanced or unbalanced?
 

While looking through a GL2 accessory overview (http://www.dvinfo.net/canongl2/articles/topfive.php#ma300), I found the following statement about the MA-300 XLR adaptor:

"If you need balanced audio connections for long cable runs, then you might want to consider a different third-party XLR adapter solution, as the MA-300 is intended for unbalanced nearby sources. "

Unbalanced sources? As long as I've been working with audio and video equipment, XLR connections have been considered balanced. Even Canon's instruction sheet for the MA-300 (which can be found in the "accessory manual" section GL2 website) indicates that the MA-300 is wired for balanced connections...pin 1 shielded, pin 2 hot, pin 3 cold. Am I missing something here?

Howdy from Texas,

I wrote that; sorry if it wasn't clear.

Basically, not all XLR cables and connectors are balanced -- some are, some aren't. The XLR connectors on the MA300 are unbalanced. Why? Because they don't need to be balanced, due to its intended use, which helps keep the cost down. The MA300 is meant for very short cable runs... either an onboard mic via the mic clamp on the MA300, or an onboard wireless mic receiver mounted on the accessory shoe on top of the MA300. These are extremely short cables, about twelve inches at most, with little chance of electrical interefence... therefore they're unbalanced (because they're not prone to hum by virtue of their on-camera location).

However, long cable runs across a studio floor, especially near sources of interference such as power cords, outlets, etc. will require balanced audio cables, and in order to preserve the protection that balanced XLR cables provide, they must terminate at a balanced XLR-to-RCA adapter, which the MA300 is not. For this job, you'll need a Beachtek (or Studio One or similar) balanced XLR adapter, which typically mounts below the camera, between the camera and tripod.

It's all a matter of choosing the right tool for the right job. For more info, see Jay Rose's excellent tutorial, "Balancing Act" which has scads more info about this topic. Hope this helps,

Check the MA-300 manual at:
http://www.canondv.com/downloads/accessory_manuals/ma-300.pdf
It indicates that the input is balanced. The output would be unbalanced, but that is not a big deal since it is mounted on the camcorder with essentially no lead length.

However, because the MA300 uses electronics rather than transformers, it does not provide the same isolation from the source as the SignVideo, Studio 1 or Beachtek would. For most users this is not an issue.

Thanks a lot, Don -- much appreciated!

Thanks for your input, guys. So with the MA-300 technical specs in mind, does this mean that the adapter does, in fact, provide true balanced inputs, or is the issue still kind of up in the air in your opinion? I guess if all three pins for each channel have an accessory shoe contact and go into the camera then the connection is balanced, however if the cold and shielded are combined somewhere along the line then the connection isn't truly balanced. With that in mind, is there really any way to tell whether or not the MA-300 provides a true balanced input connection?

The GL2 does NOT have balancd inputs, thus the MA-300 has to have a unbalanced output.

However, the input to the MA-300 is balanced, it provides the balancd to unbalanced conversion. If it is the same circuits as the MA-100, it does this using operational amplifiers. There are standard circuit arrangements for doing this.

The benefit of a balanced connection is noise reduction due to the common mode rejection of the amplifiers. (If the same signal is present at the + and - input, it is cancelled).

Because the MA300 is close-coupled to the camcorder (closer than the Beachtek, etc. would be), there is minimal chance for noise pickup in the couple inches of unbalanced connection between the MA-300 and the GL2's peamp.

Sorry if I'm beating a dead horse, but I'd like to see if I'm understanding Don's post. The way I now understand it, the MA-300 XLR inputs are, in fact, balanced, and so if I, for example, I were to connect the stereo XLR outputs of a mixer to the MA-300, I would have balanced outputs from the mixer going to the balanced inputs of the MA-300. That said, this connection would benefit from the advantages of using balanced connections...low interference for longer cable runs, etc. However, within the MA-300, circuitry provides a balanced to unbalanced connection for the audio signal actually going into the camera, so the signal going into the GL2 is actually unbalanced, however this makes little difference since the connection between the MA-300 and the GL2's audio circuitry is relatively short. Is this reasoning correct?

That said, aside from the fact that the Beachtek and other after-market XLR adaptors have features like level adjustments and so on, is it safe to conclude that the MA-300 is similar to these in terms of performing the balanced to unbalanced conversion?

Your summary is correct.

For most purposes the MA-300 and Beachteck, etc, will have similar perforamnce when use within their design operating envelope. However, the MA-300 (if like the MA-100/200) should be used with mic-level signals only (and it may offer some gain, which the Beachtek, etc. will not. ) It is not designed to use line level signals, and will go into clipping if you connect a typcial line level input to it. The -35 dB mic-level putput of most mixers is OK, the +4 dB level is NOT.

Thanks for the note, Don. By any chance, would the GL2's microphone attenuator on/off setting allow line-level XLR signals to be sent to the MA-300 inputs? If not, then I can't say I exactly understand the purpose of the microphone attenuator setting, unless it's to be used for connecting a line-level signal to the GL2's 1/8" stereo microphone input.

The MIC/MIC ATT setting changes the sensitivity of the min inpout form about 0.001 ivolts to about 0.030 ivolts. It is used when you are in a very loud venue, or have a very sensitive (high output) mic. Think of it as a 2-position volume control.

Line level signals are on the order of 0.300 volts for consumer gear, or 1.0 volts for professional gear. A one volt sine wave is has a voltage swing (peak-to-peak) of abotu 2.8 volts.

Speaking about the MA-100 (the MA-300 is probably similar) a line level signal is large enough to cause the amplifirs in the MA-100 to start to clip/distort. No surprise as it was designed as a microphone adapter. YOu can obtain in-line attenuators with XLR connectors (offered by Shure and others) to address this level issue.

Now that I understand the function of the MIC/MIC ATT setting, does this mean that even with the MA-300 out of the picture, it wouldn't be possible to send a stereo line-level signal to the GL2's 1/8" mic input without any external attenuation? I understand that the GL2 does have manual audio level controls, but nonetheless I doubt that it would be possible to properly use a line-level source with the mic input without having some type of attenuation, which I now realize would probably have to be external since it doesn't appear as though the GL2 has an internal mic to line-level attenuation setting. It's too bad that Canon didn't build this kind of setting into the GL2, especially since it's considered considered a pro/pro-sumer camera.

Without access to the GL2 circuit diagrams, or a GL2 for testing, can't say for sure, but it is likely that the input signal to the GL2 mic jack should not exceed around -10 to -20 dB peak for best performance.

Why not try run some tests to see what the limits are for your system and share the results with us all.

I'd love to test the GL2 for line-level inputs, but there's still the minor issue of not having even purchased the camera yet :) Guess I'm just the type of person who likes trying to read up on every little detail before making a purchase. Anyway, if anyone has tried using a line-level source with the GL2's standard 1/8" mic input, any input regarding compatability and/or level mis-matching would be appreciated. Thanks!

Looks to me from the GL2 manual that the mic jack is designed to accept only mic level inputs,

It appears to me that the only times line level (- 10 dBV) audio input is accepted is when doing an audio dub or recording in VCR mode using the A/V input. This is more or less addressed in the GL2 manual that you can download on line from the Canondv web site if youhaven't already.

But the apparent mic-level limitation is not a significant problem, it can be addressed quite nicely with some simple adapters.

line level
 

I think the ma-300 has a auto sensing circuit for line level inputs.

I had the same problem!
The answer is that you dont have the ma300 pushed in all the way (it will click). also the display on the camera will have a letter "C" for connection. the video does not go thru the hot shoe connection, it comes thru the other cable off the back. That is why the video worked but the ext mike was not.

Do not expect the MA300 to have any auto sensing in it, and expect it to not like line level signals, it is a mic adapter.

Beleive taht the GL2 allows selection of MIC or MIC ATT settings. Use MIC ATT with hot mics and in loud venues. It will provide the better noise floor when recording.

MA300 mic holder
 

What do I use to make the mic I just bought fit snug in the MA300 mic holder?

John, I'm supposing you've got a smaller diam than the Canon mics . . that's why you are asking - yeah?

Up to now I've used a strip of car innner tube rubber . . it's flexible, it's free .. so you can loose it without any financial fears. . go to any garage and ask for an old one! ; it's a bit non-isolating for cammie noise . .. but it's firm and keeps my Senni66 from going walk-about - yeah? Just cut out a strip for your requirements.

There isn't much space between the the clamp and the mic itself to insert a more damperning type liner. If there is, I'm interested!

Grazie

I use a long strip of black felt rolled several times around my mic (ME66).

Ah! Now that SOUNDS good! Good dampening suspect?

Grazie

Thanks to all, I 'll have to give it a try.

XLR "Y" Cable and GL2 MA300
 

I've got a GL2 w/ the Sennheiser ME66/K6 shotgun, and I was wondering if anyone had tried using a XLR Y cable from the Mic to both L and R inputs. Could you use your manual sound, and set the R to a higher gain and the L for lower in case of a sudden loud noise that may clip on tape? Just wondering as I'm shooting a documentary on Explosive Demolition beginning next week down in New Oreleans. Just trying to get the best sound of course, but I'll have 3 other MiniDV cams and 2 DATS as well.

One more thing while I'm talking about the ME66, I've used it for a year now with outstanding results, but can someone explain the switch on the actual mic that looks like --\ it's right by the power button, i'm guessing it's some sort of attenuator, but when would be the best time to use it or keep it off? Thanks,

Mike

Jesus, I meant the K66 bass roll-off filter, anyone use it? Sorry,

Mike

Yes, I created, "...XLR Y cable from the Mic to both L and R inputs". This was to ensure a colleague of mine had "both" channels on his AVIO edit system. He wouldn't copy one channel to both in post . . hey, sometimes yer have to go with the flow ;-)

Okay - I'm really trying hard to get my head around what you said next,"Could you use your manual sound, and set the R to a higher gain and the L for lower in case of a sudden loud noise that may clip on tape? " - I'd be thinking that adjusting either or both would only give you a higher or lower audio on THAT channel. Loud bangs or distorts would be captured on either one of the channels. In which case wouldn't you be back to square one? - I'm really having a problem with this concept . . . .

As for the Bass roll off, I've kept it on all the time. Nothing logical about my approach. Oh, there was a nice little graphical representation of the Bass Roll-off effect somewhere. I believe it was with my Senni66 kit when I got it. You could do a search on the Senni Site to get some info . . In the meantime could you please explain a bit more fully your ideas anout the Y split to both channels . . it's doing my brain in!

Hope some of this is helpful,

Grazie

The bass roll-off switch is common to many pro microphones. Essentially, it helps to filter-out low-frequency rumble.

Try changing the switch while recording near a motor or some other low-freq noise source to understand the effect.

Thanks for the bass roll off info, I've never had it on. I read somewhere that'd it'd be a good idea to y split the XLR cables so that you could set the ideal level of sound for example the left channel. Now for the right channel, set the gain lower but so the sound is still clean. That way, if an unexpected LOUD noise comes about and you dont' have time to ride the levels, the Right channel would have still picked up the clear LOUD noise w/o clipping on the tape. Basically, it acts as a back up.

Mike

Unless you are experiencing problems w low freq rumble or noise, it's best to leave the switch off. Why would you want to limit the range of the mic you spent big bucks for? Some folks use it when trying to cut down wind noise and it does help some but comes no where near a good wind screen.

I also read (In Real World Video) that when recording mono, you can Y split and set one channel at 0db and the other at -20db. So you get your optimal audio at 0 db BUT, if something happens to send that optimal over the edge and ruins the audio (that you normally would be capturing mono on just one channel), the -20 db channel acts as a back up, to be edited in at the appropriate spot in post.

If this is a BAD idea, I'd also like to hear from those who know...

Using a Y cable from one mic into two channels and with one channel set higher than the other is a great way to record sound if you are not able to ride levels or don't have a person dedicated to mixing the sound.

However, if the "loud" peak is louder than the mic's maximum db range than you will get distortion on tape regardless of how low you have turned the level down, especially with electret mics like the sennheiser K6. On the other hand, most dynamic mics on average have a much higher maximum db range and perhaps you should be using two mics for the purpose of recording explosive material. I personally use the sennheiser e835, which is very rugged and for a dynamic mic has a great frequency response.

Bass roll off is good if recording in high wind environment, but you still have to use a windshield other wise it will not do much in that regard. Do some tests like Ken says to see what difference it does make... and do listen to the material on a system that can produce good bass... u might be surprised at how much different the characteristis of the mic changes with the bass roll-off on and off.

Cheers,
Jack

. . .erm, I don't get this one at all . . . .
 

. . I really think I missing the point here . . . As the output, whatever that maybe, going basically into 2 channesl give the "same". How does one manage this in post . . . I'm obviously missing a fatal flaw in my awarenesses here? . . Somebody put me out of my misery . . .

Grazie

If you have the one mic split via a Y cable into two channels and one is set lower than the other then in post you should only really use the one track, either the left or the right. If the left is set to a normal level and there is a distortion in one part of the recording, there is a good chance that the right track will not be distorted at that point as it has been recorded lower.

So in that case you would have to mix from one to the other (ie left to right and then back again to take out the distoted part. Obviously you have to mix the sound into mono during the edit or afterwards so that you dont end up with sound in just the left or right channels.

Hope this clears it up.
Jack

Ah - Clear as a Bell!
 

Thanks Jack. I think I was confusing the option to use mic att, which I have used to great avail, saved me and the shoot on a number of occasions. I was thinking that maybe one could mic att just one, either or both channels separately. This is where I was confusing myself. So all you are saying is that one would physically "reduce" one channel, THEN in post separate the 2 channels and Pick \'n Mix from either - yeah?

The last part of what you say about the need to Pan the mono I understood. I do this in Vegas all the time now.

So, no separate XM2 mic att for each channel, just a reduction in the audio of each channel - got it!

Not in misery anymore.

Grazie

Yes that\'s exactly right Graham.

One more note; mic attenuation is good for most things, but the original poster Michael mentioned recording explosive material and that IMO would still be too loud for mic attenuation.

I was recording a band once and although I was recording the sound onto minidisc from the mixer, my camera\'s sound was very distorted even after using mic att. and turning down the volume a lot. I was fairly close to the speakers and like I mentioned in my prebious post, if the sound pressure level goes over the mic\'s maximum it will distort no matter what.

Anyway, Im glad you now know what I was saying before.

Cheers,
Jack

AVIO?
 

Graham, you let A FRIEND use one of those? I had the bad luck of having to rely on that wretched machine in an under budgeted high school video class. It is by far the WORST machine i have ever used! An old iMac with iMovie is 100X the machine at half the price! But, hey... thats just me on a rant.

"Graham, you let A FRIEND use one of those? " - . . er no! He had it a long long time before I ever knew him. And, just for the record he has produced some remarkable wedding videos. PLUS he is a very good cameraman and FRIEND! - He just wanted the single track spread to 2 tracks . . .

Happy New YEar . . Grazie

Anyone thought of building a circuit for the ma300
 

I just had a thought, don\'t know if this is possible, but what about building a phantom supply into the ma300 adaptor? has anyone tried this?