MM1 + Lectro UM400 for wireless boom

[Fernando]

Hi,

Is anyone using a SoundDevices MM1 into a Lectro 400 transmitter for

w. boom?

I was planning to use a phantom box plus a monitor box for this (to

listen to both the mic boom and a walkie for communication with sound

mixer) but I know some are using the MM1 for this task.

I see the MM1 has pretty large gain increments (0, 18, 36... dB)

It would be better to control gain at the MM1 than at the Lectro TX

since it's knob is not intended for continous readjusting (small and

near a connector), letting the Lectro at maximum gain (since it is,

iirc, an attenuator) and then adjusting gain at the MM1, but then you

jump from 18dB to 36dB of gain... so I wonder how you would set up

this tandem.

I also don't like the idea of having two gain controls controlled by

the boom op (pre and tx), it can be too distracting in some

situations.

BTOH, I wonder about the benefits of performing preamplification to

line level before the Lectro or if it would be better to feed it with

mic level and just control the input gain of the TX.

The boom mics being used are mainly Schoeps CCM41 and Sennheiser MKH60

and soon Sanken CS3e.

The current TX is an UM400.

Fernando

[John Blankenship]

"...letting the Lectro at maximum gain (since it is, iirc, an attenuator)..."

I believe that is not quite the case.  You may be thinking of the output of the Lectro receivers which always operate at maximum gain and then use resistive padding to adjust the output level.  The transmitters, (someone please correct me if I'm wrong) have a gain stage prior to the input level adjustment.  Operating it wide open is going to give you a lot of extra noise.

John Blankenship, C.A.S.

Indianapolis (Super Bowl Champions!)

[t.elder]

"...letting the Lectro at maximum gain (since it is, iirc, an attenuator)..."

I believe that is not quite the case.  You may be thinking of the output of the Lectro receivers which alwas operate at maximum gain and then use resistive padding to adjust the output level.  The transmitters, (someone please correct me if I'm wrong) have a gain stage prior to the input level adjustment.  Operating it wide open is going to give you a lot of extra noise.

John Blankenship, C.A.S.

Indianapolis (Super Bowl Champions!)

You are right - the transmitters have an independent gain stage.  I generally use a wireless boom set-up and I often tell my boom operator to set the gain on the Lectro TX according to the scene's dynamics.  Opening the TX's gain all the way will result in a lot of extra noise and a lot of overmodulated signal.

Tim

[Fernando]

IIRC, Larry Fisher said the potentiometer on the UM400 was just an attenuator = you have all the gain available and pad the input going CCW

"...letting the Lectro at maximum gain (since it is, iirc, an attenuator)..."

I believe that is not quite the case.  You may be thinking of the output of the Lectro receivers which alwas operate at maximum gain and then use resistive padding to adjust the output level.  The transmitters, (someone please correct me if I'm wrong) have a gain stage prior to the input level adjustment.  Operating it wide open is going to give you a lot of extra noise.

John Blankenship, C.A.S.

Indianapolis (Super Bowl Champions!)

[Fernando]

This would be the case if boom mic --> phantom box --> TX

Using an MM1 you would set the gain at the MM1 and have the TX fully open ideally. But the problem is that actually the MM1 has big gain steps, fact that makes me think I would have to set the MM1's gain at +18 or +36 and adjust TX input level anyway...

That's why I'd like to know if someone is working with MM1+UM400 and if it's a comfortable and practical setup, gain-wise.

What do you use between boom mic and TX?

You are right - the transmitters have an independent gain stage.  I generally use a wireless boom set-up and I often tell my boom operator to set the gain on the Lectro TX according to the scene's dynamics.  Opening the TX's gain all the way will result in a lot of extra noise and a lot of overmodulated signal.

Tim

[John Blankenship]

Fernando,

Again, I think you are confusing the transmitter with the receiver.  The Lectro receivers operate at full gain and pad down the output to whatever level you choose. 

Although my conversations with Larry have been about the 200 series transmitters, my guess is that the 400 series is similar.  In the 200 series there is a buffer stage prior to the level control.  The buffer stage will handle about 1.5v. RMS.

Easier than arguing, however, is to turn your transmitter gain full up.  I think you'll hear excessive noise.

John Blankenship, C.A.S.

Indianapolis (Super Bowl Champions!)

[curleysound]

Are we looking for a set and forget setting on the xmtr? Is there such a thing? I have been addressing gain structure on a scene by scene basis on what the loudest sound expected for that scene will be. If I'm dealing with one of those roller-coaster voices, then I'll err on the low side to avoid getting blown out. The xmtr has a convenient little 2 LED meter, which you can turn up to peaking, and back off a bit. Also, the 200 & 400 series receivers have a calibrated level meter on the display, so in theory, you can measure the input level as received there.

My $.02

Tom