DXA-8 - AT897 - GL2 Settings
 

Hey Guys

I have been searching around reading a lot of threads on this subject but still have not found the answer to this:

With the DXA-8 XLR Adapter, AT897 Mic on a GL2 I read I will be feeding line level audio in from the 897 but also read that the cameras mic input looks for mic level - does this mean I have to make sure I turn down the camera levels all the way and just use the levels on the DXA-8? Will this assure that I am only using the preamp on the DXA-8 and not on the camera? Should the MIC ATT be on or off with this set up?

And yes of course I will be using headphones for monitoring audio. 8)

Thanx for any help as I am a relative newbie when it comes to audio recording.

The AT897 will be sending mic level into the DXA-8. You would then use the preamp to give a slight boost and use Mic ATT on the camera. At least that's what I'd do as a starting point.

The respective specs of the GL2 and the DXA-8 absolutely require that MIC ATT be on when they are used together. That much is clear

But if the level setting instructions that come with the DXA-8 don't make sense to you, you're not alone. I used to have one. They want you to turn the GL2's audio gain way down and compensate by cranking up their preamp until the limiters begin to kick in. I guess the rationale is that their preamp is supposed to be superior to the GL2's. What doesn't make sense is that they don't seem to acknowledge that the ouput of their preamp is the input to the GL2's preamp. And the GL2's meters are for its *final* amplifier stage--they don't indicate whether its preamp is being overdriven.

I prefer the idea of starting with the GL2's controls at 2/3 to 3/4 then adjusing inputs until the GL2's indicators hit 0 dB, then backing off a little on the GL2's controls. That gives me reasonable certainty that the input to the GL2 is appropriate.

Am I wrong, Jay?

The DXA-8 is mic level. The DXA-8 is fairly easy to set up and if you have a problem just call Harry at Beach. It's a super simple solution, why make things more complicated?

If the camera preamp is OK then set the manual gain for 50% - 60% and go on from there. I always try and operate anything at mid range, just a habit.

Bryan,
I like BeachTek adaptors, but the instructions shipped with the DXA-8 just plain suck. For instance, your advice contradicts those directions. Tell Harry that for $360 a customer who can read shouldn't have to call.

The instructions don't cover all the bases but neither do the instructions for the mix pre or the 302. The low on board gain is meant for the Sony preamps. If you have a beef call Harry, I'm sure he'll listen.

Lets stay focus on the original problem. Each camera and mic setup is unique regarless which mixer/preamp you use.

Todd
Read my write up here

Try setting the Camera gain at 50%. Plug the mic into the Beach and set the gain of the Beach at "0".
Power the Beach and speak into the mic at a normal distance while monitoring the GL2 meter as well as listening with head phones. Slowly turn the beach DXA-8 gain until the peaks are hitting -12dB.

I own a DXA-8, a MixPre and a 302 and they all take some getting used to. It's a learning experoience so stick with it.

Feel free to email me at bbeasleighatrogersdotcom.

I know BeachTek would love to help as well, they're good people.

Thanx Bryan

I had read your article and came away even more confused about what exactly is happening with the DXA-8 and my GL2. Certainly no fault of yours as your article wasnt meant to explain basic sound concepts which is where I fear I am at the moment.

My thinking is this (which is most probably flawed):

The DXA-8 has a pre-amp
The GL2 has a pre-amp

The DXA-8 pre-amp is much better and lower noise than the GL2 therefore..

The GL2 gains should be turned down as much as possible to limit or eliminate the pre-amp there while turning up the pre-amp on the DXA-8 to get cleaner amplified sound.

Since turning the pre-amp on the GL2 all the way down yields no sound at all even with the DXA-8 preamps turned all the way up you must turn back up the GL2 pre-amp levels only so that the sound is registering and recording.

Am I thinking about this in the right way or am I way off?

Thanx for any further help

As I said, start with the GL2 at 50%

For safety start with the Beach at 0 gain

Increase the gain on the beach until you can see the peaks in your camera meter hitting -12 db

If you don't understand that then maybe you should have someone show you in person.

Sorry Bryan

I didnt explain myself very good I guess.

I understand your steps just fine and again thank you, but the steps themself don't help me to understand what is happening "under the hood" so-to-speak.

This is what I need to understand so that I can come to my own conclusions and steps that I feel are correct for the set up. Even you yourself admit in your article to being a "sincere amateur"

Am I being more clear now in asking for a better understanding?

Thanx again.

I think you're understanding the goal just fine, which is to get the cleanest sound by using more gain from the cleaner of the two preamps. In practice though it's not that extreme. Especially when you're already using the Mic ATT setting on the camera. This will generally mean experimenting with the settings on both devices starting out somewhere in the middle ground.

I think you understand the situation. The reason I always start at mid scale is that's pretty well the safest and most accurate area in any piece of electronics. Do some experimenting until you develop a "feel" for the equipment.

OK thanx again guys - One other question I have is concerning the use of phantom power vs. battery power on the AT897.

The specs on the 897 are different in some areas when using phantom vs battery:

Open Circuit Sensitivity
PHANTOM: -40 dB (10.0 mV) re 1V at 1 Pa
BATTERY: -41 dB (8.9 mV) re 1V at 1 Pa

Impedance
PHANTOM: 200 ohms
BATTERY: 300 ohms

Maximum Input Sound Level
PHANTOM: 129 dB SPL, 1 kHz at 1% T.H.D.
BATTERY: 115 dB SPL, 1 kHz at 1% T.H.D.

Dynamic Range (typical)
PHANTOM: 112 dB, 1 kHz at Max. SPL
BATTERY: 98 dB, 1 kHz at Max. SPL

It would seem phantom power is a better choice, but I am not sure about this. Can anyone shed some more light on the differences?

Much appreciated!

Yes, phantom power will give better performance from the mic. The sensitivity gained by phantom is small, but in a quiet situation that could be helpful in keeping the noise down a little.
On the other hand, the difference in dynamic range and max SPL is substantial. That would only come into play in loud situations.
However something as simple as a cheering crowd indoors can get very loud, so any benefit helps.

Using the internal mic battery will increase the life of the DXA-8 battery. As Jay says the difference will be felt in noisy situations.