Hey guys-
I'm in a pickle. I've captured some footage on my GL2 with two external mics through a Beachtek DXA-6 (one left channel and one right channel). When I put the video on my G5 (using Final Cut Express HD), I can't edit the channels individually. Is this possible? To edit the left channel separately from the right channel? Or am I just lost in the sauce? I know a lot of you probably dont use FCEHD, but does any other program let you do this (i.e. Vegas, FCPHD?) Someone please shed some light.
Thanks!

Hi Brett!

Off topic:
Many of the DXA-6 records the stereo signal out of phase. This was corrected about 2-3 months ago by BeachTek. Combining a stereo signal with each channel recorded out of phase is a catastrof.

If your DXA-6's volume controls has 10 steps it will record the stereo signal out of phase.
If your DXA-6's volume controls has 30 steps it records the signal in perfect phase.

This phase problem can be fixed easily by any electronic technician or by BeachTek so that it records in perfect phase. And if you have a DXA-6 that records out of phase you can correct it in a audio editing application, so it can be solved anyway.

On topic:
I use Premiere Pro and can edit both channels individually by either using a function called Break Out To Mono in Premiere Pro or duplicate the two stereo tracks and edit, or use a audio edit application and create two mono files out of the stereo file.

/Roger :)

Hi Brett!

Off topic:
Many of the DXA-6 records the stereo signal out of phase. This was corrected about 2-3 months ago by BeachTek. Combining a stereo signal with each channel recorded out of phase is a catastrof.

If your DXA-6's volume controls has 10 steps it will record the stereo signal out of phase.
If your DXA-6's volume controls has 30 steps it records the signal in perfect phase.

This phase problem can be fixed easily by any electronic technician or by BeachTek so that it records in perfect phase. And if you have a DXA-6 that records out of phase you can correct it in a audio editing application, so it can be solved anyway.

/Roger :)

Thanks Roger-
What is the difference between a track that is recorded "in phase" and one that is recorded "out of phase"? Is there any audible difference?
Thanks.

What is the difference between a track that is recorded "in phase" and one that is recorded "out of phase"? Is there any audible difference?
Yes, there is a audiable difference. I am not the right man to explain "how" it sounds but the sound "looses" it's low frequencies and sounds "hollow". If you play a stereo signal that is out of phase through a mono system most of the signal dissapears... (Somebody else can probably give a better explanation...)

There is no audiable difference when you play either left or right, but when you play left and right at the same time you will here the difference.

Here is a short sample of two files, one are in perfect shape and one is out of phase:
http://members.chello.se/averdahl/phase.zip

/Roger

Ha! That's a hoot!

I guess their faces were pretty red.

Out of Phase (better termed Reversed Polarity) is that condition in which the positive peaks and negative peaks of one channel are reversed on the second channel. (Usually by a pair of wires being reversed)

As the sound peaks positive on channel one, it's peaking negative on channel 2. Although there are some folks who can identify absolute polarity, most folks hearing each channel separately can't tell the difference.

HOWEVER!!!, whe you add the two together in MONO, the positive peaks cancel the negative peaks and in doing so the sound is reduced and sounds pretty weird.

This "effect" is what is used in Vocal Scrapers to remove vocals from records. One channel has its polarity reversed and the two are then combined to mono. Because the vocal is usually panned to the center of a mix, it will cancel out. Kick drum and bass also usually are in the middle of the stereo spectrum and they also cancel out. Sometimes you hear the vocal reverb, but not the main vocal. That's because there are slight timing differences between the two channels, so cancellation doesn't happen as completely.

How's that?

Ty Ford

Wow guys, thanks for the replies! I understand now :) So if I call Beachtek, will they fix my DXA-6 for me? It is the older style one. Anyway, thanks again.

Wow guys, thanks for the replies! I understand now :) So if I call Beachtek, will they fix my DXA-6 for me? It is the older style one. Anyway, thanks again.
If it's still under warranty BeachTek will fix it, but you have to pay for the shipment to and from BeachTek in Canada. :( (send them a mail and ask how they can solve it since the DXA-6 had a faulty design.)

If it is not under warranty i am sure Mr Kaufmann will fix your DXA-6. More info: http://www.beachtek.com/questions.html (take a look at the question "How do I get my adapter repaired?")

It is very easy to fix the problem, so a local electronic technichian will fix it easy. It will take just a couple of minutes and will save you money.

At last, Mr Kaufmann at BeachTek has been very co-operative regarding this matter from day 1 when i first told him about my findings. :)

/Roger

if you're getting an out of phase recording, just resolder your connections on your XLR cable. i believe you swap the red and white? (the two that are not the ground). resolder them on both ends that way you have two different microphone cables... one normal one and one set for out of phase conditions... make sure you mark the out of phase one.

Um, if you resolder both ends of the same cable, (swapping the connections), you're right back where you started.

Regards,

Ty Ford

Roger-
What has to be done to fix the Beachtek? I have a friend that is an Electrician, and I know he could fix it if I were to tell him what to do. He is also very good with Audio equipment, so he might not even need me to tell him what to do, but for my sake, could you please kinda give me a run down of the process?
Thanks a ton!
-Brett

What has to be done to fix the Beachtek?
Hi Brett!

I made a simple homepage with two pics of my DXA-6 and a simple "how-to-do" guide. If you have any questions, just post them here! :)

My box was modified by Mr Kaufmann at BeachTek before i bought it.

http://members.chello.se/averdahl/dxa6fix

/Roger

Wow thanks Roger! You rock!
-Brett

You're welcome Brett! :)

/Roger

My DXA-6 is the VERY original version, it only has phantom power for one channel. It uses a totally different switch layout so hopefully it doesn't have the same circuit pathways. I'll have to test it when I get a moment. I've never done true stereo through it, only single and dual channel mono.
I already have a phase reversal cable handy since one of my Chinese mics has reversed polarity. You can also buy an inline barrel phase reverse switch from Shure and others, I think I have a couple of those too.

Roger-
I noticed in your graphics, that only one side is talked about. Do I have to do that procedure to both XLR inputs, or just the one you've shown?

Also: I have the DXA-6 that has Phantom power on only ONE side. Does this make a difference? I asked the question about doing the procedure to both sides because one XLR input has power (a red wire) going to it. What will happen if I switch the wires?
Thanks.

I've quickly tested my very early DXA-6 (with phantom on only one channel). The two XLR connectors are out of phase with each other.
I would have to do further testing to say which side is reversed and which side is correct without opening my box. You would only modify one side to correct this problem. Correcting either one will make it right as far as the BeachTek is concerned, but if you change the good side to match the out of phase side, then you'd be making your camera wrong when combined with another recording device. Since any of these devices that we'd be recording with can't be locked together precisely enough to maintain an in-phase or out-of-phase condition it wouldn't be a total disaster. We already know you're not even going to try to lock two copies of the same audio from different devices, like multiple feeds from a mixer except to obtain sync and then use just one copy for final audio. However, it would be a lot easier to work with two pieces of equipment that are in phase rather than out. It's easier to sync by listening to a boosted and phasy signal rather than one that cancels to nothing some of the time.
It would be easier to just change the non-phantom side, since you wouldn't have to worry about the extra power connection, but I'm not sure whether that's the good or the bad side.
Since I will rarely have this problem, I think I'll rely on an external reverser. I'll let you know when I have a chance to find out which side is in and which side is out. Maybe that's already known by one of these posters or you can tell by looking inside your own BeachTek.
I think the error occurred because the two XLR connectors are rotated 180 degrees apart in order to make them easier to unplug. The circuit traces also needed to run opposite of each other to match this physical arrangement.
For other owners wanting to do a quick test on their BeachTek, you don't even need to actually record anything. Use a tone generator or a single output from a CD player, either Left or Right. Input this signal to a mixer and keep the input Pan Centered. Take the two outputs from the mixer into your BeachTek, set for Line Level. Set the BeachTek switch to Mono. If you can't hear anything while monitoring your camera until you pan the mixer input left or right, then your BeachTek XLR inputs are out of phase with each other. This assumes your two mixer outputs and the two cables are all correct.

oops my mistake! phase reversing a cable is pin 1 to pin 1, pin 2 to pin 3, pin 3 to pin 2.

Roger-
I noticed in your graphics, that only one side is talked about. Do I have to do that procedure to both XLR inputs, or just the one you've shown?

Also: I have the DXA-6 that has Phantom power on only ONE side. Does this make a difference? I asked the question about doing the procedure to both sides because one XLR input has power (a red wire) going to it. What will happen if I switch the wires?
Hi Brett!

If you fix both channels you are back at square one! You should only modify one of the channels. Right channel is the easiest to modify on the DXA-6 and is the channel BeachTek fixes.

The phantom power is not affected on my DXA-6. But the only cables you should change is the cables where the audio signal passes. Do not modify the cables from the phantom power.

The modification done at my DXA-6 by BeachTek did not affect the phantom power supply on my DXA-6, phantom power works at both channels. :)

/Roger

I've quickly tested my very early DXA-6 (with phantom on only one channel). The two XLR connectors are out of phase with each other.
I would have to do further testing to say which side is reversed and which side is correct without opening my box.
Hi Jay!

I tested a faulty DXA-6 in july 2005 and compared the channels with a Panasonic camera XLR-inputs and i am almost 100% sure of that it is the left channel that actually is the channel that is out of phase on the DXA-6's and should be repaired. It should be very interesting to see your test results Jay.

/Roger

Hi Brett!

If you fix both channels you are back at square one! You should only modify one of the channels. Right channel is the easiest to modify on the DXA-6 and is the channel BeachTek fixes.

The phantom power is not affected on my DXA-6. But the only cables you should change is the cables where the audio signal passes. Do not modify the cables from the phantom power.

The modification done at my DXA-6 by BeachTek did not affect the phantom power supply on my DXA-6, phantom power works at both channels. :)

/Roger

Thanks for all the advice Roger and everyone else! So let me get this strait... I should only modify my Right channel (the one without the Phantom power). And all I have to do is to switch the connections on Pin 2 and Pin 3 (connect Pin 2 to where Pin 3 was and vise versa)? Is this correct?
Thanks again.
-Brett

So let me get this strait... I should only modify my Right channel (the one without the Phantom power). And all I have to do is to switch the connections on Pin 2 and Pin 3 (connect Pin 2 to where Pin 3 was and vise versa)? Is this correct?
Yes, thats correct! :)

/Roger

On my particular DXA-6, the Left channel is IN phase and the Right channel is OUT of phase, at least when comparing with Sony cameras. This is good because I don't have to worry with the phantom circuit at all since it doesn't go to the right channel.
Interestingly I had the materials to test right in front of me. I'm currently editing a project where I used a BeachTek-equipped D8 camera to record a visual reference of the projection screen so I could lay in the rendered .png PowerPoint slides easily in post. I was sending a feed of the podium mic to the left channels of both the DSR-390 DVCAM main camera and the TRV-103 D8. They were in phase with each other.
Two more points of interest. There was enough difference in the frequency response of the two cameras that they only had minimal cancellation (about 2db) even when one was purposely inverted.
They also held sync amazingly well, drifting less than one frame in about 53 minutes. Too bad it didn't matter, the D8 footage will be deleted as soon as the slides are in position.
I also tested both the Left and Right of the D8 camera against each other visually in a separate test. This also showed the Left channel of the BeachTek was in phase and the right was out.
All this assumes that the Rode and Sennheiser mics, the Mackie and Peavey mixer outputs, and all the cables used were in phase.
One last note about the BeachTek. Keep in mind that the Left input is directly behind the Right control when viewing from the front. I know I should have been looking at the labels more closely, but when I first hooked up the BeachTek long ago I confused myself until I checked the labels more closely when looking at the input (back) end. I made certain to double-check them for these tests.