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Old May 4th, 2006, 04:21 AM   #1
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Beachtek Trim Controls - Noise Problems During Recording?

Firstly, hello to everyone. I have been reading these forums on and off for the last couple of years and they’ve been really useful, but this is my first post!

I am an amateur video maker - nothing too serious. I make videos for friends and family. I have a Panasonic GS400 and a Rode Videomic.

I usually set my audio levels manually on the GS-400 using the camera’s menu system. However, I am finding this restrictive as I can not adjust my levels up or down during recording because the camera does not allow it. I have to stop recording, go through the camera menu, adjust the gain up or down, and then start recording again. Very frustrating.

I would like better manual control of my audio levels.
I read that a cheap solution was to buy a headphone volume control and plug it between the videomic and the camera. I’ve tried this, however the volume control is adding quite a lot of unwanted noise to my audio, particularly when I adjust the volume control – there is kind of a hissy noise – which destroys the recording.

I would love a proper mixer but unfortunately because I am usually working by myself in handheld situations I don’t have enough hands to operate my camera and a proper mixer at the same time (or the budget for a decent mixer).

I thought a solution to my problem would be to buy a Beachtek DXA-2S and plug my videomic into that. I could then use the trim control on the Beachtek to adjust the levels entering my camera when needed (while I am recording).
However, I read the user manual for the Beachtek and it says
“Try to avoid adjusting the trim controls on the adapter while recording as this may introduce contact noise from turning the potentiometers - instead, set the levels prior to recording.”

As a result, I would like to ask people who have used Beachtek adapters – have you experienced this problem (noise being introduced when you turn the trim controls during recording). If turning the control during recording is really that bad, I would be wasting my money.

I have read about another type of XLR adapter with trim controls called the XLR-BP™ Pro XLR Adapter
http://studio1productions.com/xlr-bp_pro.htm

Is the XLR-CP Pro’s trim controls any better than the Beachtek’s?

I am more attracted to the Beacktek because it fits underneath my camera, where as the XLR-BP Pro does not. Is there any reason that the XLR-BP Pro is better than the Beachtex DXA-2S?

Also, are there any other methods I can use to have better manual control over my audio levels?
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Old May 4th, 2006, 03:45 PM   #2
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I am a little surprised by the comment in the manual about not adjusting the trim controls during recording. However, I believe what Beachtek is saying. I assume that it applies to that model of adapter.

I have, and use, a Beachtek DXA-8 adapter. This unit has many advantages in that it has a good preamplifier and limiters. The preamplifiers allows you to overcome noisy preamplifiers in some cameras. If you can afford it, I highly recommend it. Of course, a true mixer, such as a Sound Devices 302 is even better, but is not always as convenient, as it can not (easily) be mounted under the camera.

I have never had any problems adjusting the levels on the DXA-8 while recording. I assume that the problem does not exist, or is minimal with the DXA-8 since you are actually adjusting the gain of the preamplifier. On the other units, ones without a built in preamplifier, such as the DXA-2S, you are directly adjusting a pot (variable resistor, essentially) which is directly in the audio path.

The instructions for the DXA-8 do not state that you should not adjust the controls during recording.

http://www.beachtek.com/pdf/DXA-8instructions.pdf
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Old May 7th, 2006, 08:30 AM   #3
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Thanks for your help Dan. I would love a DXA-8 or Sound Devices 302 but unfortunately they are beyond my poor student budget at the moment :(

Are there any Beachtek DXA-2s users out there who can comment on how bad the noise problems are when they adjust their pots? I was browsing some other threads and read one comment suggesting that it wasn't noticeable...

Also, do people find having a Beachtek adapter screwed in underneath the camera annoying if when they are handholding the camera? Does it make it difficult to hold the camera?
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Old May 8th, 2006, 07:43 AM   #4
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The Beachtek units, in my opionion, will not get in your way when you are hand-holding the camera. Of course, you will be tethered to a microphone unless you are using a wireless setup.
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Old May 11th, 2006, 02:24 AM   #5
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Ohh, I am now able to afford a DXA-8, which is very exciting!

(I did some work experience for a company and they decided to reward me buy buying me something for $200AU... but now they've bumped it up to $500AU).

One question - I was browsing some other threads and people were commenting the the lower end beachtek's have stops on the trim controls that click into place (which makes adjusting the controls during recording undesirable).

Do the controls on the DXA-8 also click into place?
(I'm presuming not given you said you've never had any problems, Dan)
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Old May 11th, 2006, 02:48 AM   #6
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Just stumbled across a sound devices unit that might work for me too

http://sounddevices.com/products/mp1master.htm

anyone used one of these?

I notice that the gain goes from 0 to 66db.

Does that mean that that at 0db there is no sound coming out of the device?
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Old May 11th, 2006, 04:42 AM   #7
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Quote:
Originally Posted by David Erceg-Hurn
Just stumbled across a sound devices unit that might work for me too

http://sounddevices.com/products/mp1master.htm

anyone used one of these?

I notice that the gain goes from 0 to 66db.

Does that mean that that at 0db there is no sound coming out of the device?
This is a true mic preamplifier (and a very high quality one). It adjusts from passing the signal through unchanged to amplifying the signal by a user-selectable amount. So "0dB gain" does not mean there's no output - it means the output signal is the same level as the input signal whatever that may be. So if you feed it a mic that is putting out a level of -50dBu, the output of the preamp will be -50dBu, still at mic level. OTOH, if you set the gain to "50", feeding it a mic level signal at -50dBu will give you a line level output of 0dBu.

Except for the DXA-8, the Beachtek adapters are variable attentuators, adjustable from the input signal not being affected to the signal being reduced by some amount.
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Old May 11th, 2006, 06:41 AM   #8
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Dear David,

I feel that you will be very happy with the Beachtek DXA-8.

The gain controls on the DXA-8 are smooth, no preset click stops.
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Old May 11th, 2006, 06:51 AM   #9
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Thanks again for your help!
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Old May 11th, 2006, 06:53 AM   #10
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Dear David,

The MP-1 is a single channel unit.

If all you will ever need is one channel, then you can consider this unit.

But instead of purchasing the MP-1, I highly recommend that you purchase the MM-1. This unit is great for use by a boom pole operator or as a single channel preamp for your camera.

These units will (normally) connect to your camera via the "Line In" input.

Sound Devices makes very high quality units with very quiet preamplifiers. But, they do not mount underneath the camera as the Beachtek units do, nor do they have two channels.

If you have even more money, the Sound Devices 302 is a very good mixer and a great investment in your production tools! (I realize this is way too expensive for a limited budget).

I have both the Beachtek DXA-8 and the 302, I do not have a MM-1 or MP-1.

For your price range, and because it has two channels, I recommend the Beachtek DXA-8.
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Old May 11th, 2006, 11:54 AM   #11
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the beachtek dxa-8 is a very different animal than the cheaper beachteks. as has been stated, it contains preamps, so that the pots on it are adjusting actual gain. on the cheaper units, as far as i can tell, the pots (which click into about 10 positions,) are simply increasing or decreasing the amount of attenuation on the mic signal. they are completely passive (hence the lack of batteries,) and there is no actual amplification going on at all. my only beef with the dxa-8 is that it doesn't put out a line level signal, which would let someone with , say, a vx-2000 circumvent the camera's crap preamps by recording at line level. for cameras that don't record line level, this isn't a consideration.
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Old May 11th, 2006, 12:08 PM   #12
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Quote:
Originally Posted by Nate Ford
the beachtek dxa-8 is a very different animal than the cheaper beachteks. as has been stated, it contains preamps, so that the pots on it are adjusting actual gain. on the cheaper units, as far as i can tell, the pots (which click into about 10 positions,) are simply increasing or decreasing the amount of attenuation on the mic signal. they are completely passive (hence the lack of batteries,) and there is no actual amplification going on at all. my only beef with the dxa-8 is that it doesn't put out a line level signal, which would let someone with , say, a vx-2000 circumvent the camera's crap preamps by recording at line level. for cameras that don't record line level, this isn't a consideration.
To go to line level with 2 channels, a good choice is the Sound Devices MixPre.
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Old May 11th, 2006, 12:43 PM   #13
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yeah, i know. i love the mixpre. i just wish they'd cram it into a slightly smaller box with a 1/4" 20 screw on it. there is a guy who'll mod the mixpre into a camera-mount unit, but i can't afford that at the moment, and don't have the stuff to do it myself. here's that guy, btw:
http://www.gregjwinter.com/modification2.htm
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Old May 11th, 2006, 12:52 PM   #14
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Both the DXA-2 and even the newer DXA-2S have "click style" trim controls that can be noisy when adjusted. The top-end BeachTek DXA-8 has nice smooth POTS that will not add any hiss or pops.

If you're really on the student budget, I gathered up all the "Reconditioned" BeachTek DXA-2 models just to help out cats like you :) We have them available at a discounted price of $79 online at http://www.dvcreators.net/beachtek-xlr-adapters/

You can also watch a quick video on the BeachTek site showing off the DXA-2S at http://beachtek.com/dxa2s.html (BTW,I'm the demo guy in the video)
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Old May 11th, 2006, 01:04 PM   #15
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Actually just to double check, I grabbed a DXA-2S from our stock and plugged in a RODE NTG-2. There are no issues with pops or hiss with the newer models that have the solid black colored knobs. Nice and clean. I'd wouldn't hesitate to go with a 2S if you need to adjust levels while recording. The older DXA-2 (silver knobs) does indeed add noise when adjusted.

Hope this helps,
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