Custom talkback unit

[klaukholm]

I would like to share our new custom job with you guys as someone else may be interested in a similar custom job. This company is extremely easy to talk with for custom work.

We had them make us a custom unit that would do the following:

1. Auto cue with bypass
(auto cue cuts the talkback AND listenback mic when transport goes to record)

2. Talkback and listenback with micpres, separate volume control

3. Talkback sent to two separate cue outs:
Cue one to headphone distribution system. This output also has a separate input with volume control for passing on click track.
Cue two to talkback speaker with volume control.
Both have defeat buttons.

4. Neumann red/greenlight tied to autocue - indicating to orchestra if transport is in record mode. Defeatable, in case you want to be a bit dishonest with the players.

Unit is one rack unit with a remote control
I will post pictures when we have it a month from now.

This is probably useless to most people, but we felt we needed a separate commmunication system that stays active when Protools and Pyramix are reloading cues on scoring sesions. Too much time is lost when you loose audio from the orchestra.

I wanted better control of listenback, without having an open listenback mic during takes.

A redlight is added to avoid false starts and cut down on time lost to the "are you rolling" question.

The autocue insures that we don't have an open mic during record unless we actively choose to do so.

[Thomas W. Bethe]

I built something like that a number of years ago and it has worked GREAT.

Ours uses the Neumann light as well with a bypass switch.

The speaker is from an old KLH portable record player. The amplifier is a McMartin 5 watt PA amplifier with a mic preamp built in and the microphone is a paging microphone from PASO. The who unit folds up into a nice carrying case. It has served me well for about 15 years. I started on a new one but did not get too far.

Sounds like a nice setup.

Do you have pictures?

[Remoteness]

Awesome!

Do you have any pictures to share with us?

[klaukholm]

I will leave this up for a week as I don't know how they feel about me publishing this drawing.

I will replace it with pics as soon as we receive it.

[Thomas W. Bethe]

Originally Posted by klaukholm

I will leave this up for a week as I don't know how they feel about me publishing this drawing.

I will replace it with pics as soon as we receive it.

Looks nice. Looking forward to the pictures. Thanks!

[klaukholm]

Guys, should I get phantom power on this baby?

We use an sm58 for talkback and maybe an sm63 for listenback, but having the option might be good.
If so, do I get 20 or 48v phantom?

Keep in mind that listenback will be up to 100 meters away from the micpre in this box.
I have never used anything but millennia for this purpose.
How do dynamic mics fare with cheap micpres and that kind of cablerun?

[fifthcircle]

Cool looking box there... I think phantom isn't necessary, but could be a cool feature. If you need the greater sensitivity of a condenser, you'll probably want a full 48v.

As for cable runs, I wouldn't worry about it. Dont' forget, the PA folks will 100-150m regularly for large concerts. The only issue you'll run into with long cable runs of dynamic or ribbon mics is buzz. Get near a strong electrical field and you can have an issue. I find it to be less of one, however, with condensers (another reason why phantom may be nice).

--Ben

[klaukholm]

Thanks Ben,
the main thing I want to avoid is any kind of hiss in the listenback speaker. I sent him a mail asking for 48v.

[fifthcircle]

To completely avoid hiss, you could buy yourself a $100 chinese condenser and use that for your listen-back. You don't need super high quality, you just need to know what is going on in a clean sound. A cheap condenser will do that a lot easier than a dynamic.

--Ben

[klaukholm]

good idea, I'll get another km184 or km183 for the listenback.

[klaukholm]

Here are some pictures of the unit in use.
I am quite happy with it. My only regret is I did not get a soft limiter on the talkback preamp.

[Remoteness]

Kjetil,

Can you install the soft limiter after the fact?

[klaukholm]

Originally Posted by Remoteness

Kjetil,

Can you install the soft limiter after the fact?

I am hoping that would be possible. There is room inside.
Is there a inline soft limiter you could recommend that could go before the mic (sm58)?

[mpdonahue]

I've built about 15 different talkback boxes over the years and have found that the circuit from the Studer 96X series consoles is the most brilliant design ever for this purpose. It has an AGC that is adjustable so there is no reason to have to be right in front of a gooseneck microphone. We use the ubiquitous panasonic electret omni capsule mounted into a flat surface so the producer or anybody else in the control room can talk and be clearly heard in the hall.
The other thing that we've done is to have a separate volume control for the monitor level during talkback rather than a fixed "dim" of 15 or 20 dB. That way if you have the volume cranked you don't get a blast of feedback when the producer hits the talkback.

All the best,
-mark

[John Willett]

I built my own talkback box about 15 years ago and still use it on every location recording.

I used the innards of an old Allen & Heath Aux Box for the mic. pre. and a cheapo Canford Audio dynamic gooseneck mic.

BBC spec. red lights were included.

The switches were hi-spec. lever switches (ergonomically the best ever made, but not available anymore). If you pull them towards you, the connection is momentary; if you push them away they latch. I used a black switch for mic. and a red one for lights.

An umbilical runs to the recording room connected to K+H M51 powered monitor and red lights.

There is also cable to connect up a headphone strip for monitoring if required.

It's the unit on the extreme right in the picture below and one of the BBC spec. red lights is on top of the right hand monitor.

The picture was taken at a recording session in The Menuhin Hall about two years ago - I have upgraded the recorder to the Nagra VI and the headphones to the HD 800 since the picture was taken.