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Old 23rd December 2012
Gear Head
I'm using a Radial MC3 and I like it, except for the fact that it uses pots, which I intend to mod.

As a switcher, it is wonderful, and meets my needs perfectly. I have it configured as follows:
Monitor A: JBL LSR28P pair
Monitor B: Bryston 4B > NS-10 pair
Aux: Behritone C50A pair

The master pot was a bit scratchy and muddy at low volumes, so I keep it all the way up. I was using the monitor pot on my 01V96 console or Motu interface to control volume feeding the MC3, but now I use the stepped switch on a Lavry DA10. MUCH better sound at ALL volumes with the Lavry!

I calibrated the system by running pink noise through the system, generated from the 01V96. Using a dB meter, I set the Lavry's volume so that I was getting 83dB out of Monitor A > JBL's at their sweet spot. (The MC3 Monitor A trim was set at max.) I then moved the dB meter to the NS-10 sweet spot, switched to Monitor B, and lowered the Monitor B trim to get 83 dB out of them. Then I switched off Monitor B and switched on the "headphones" and moved the front panel headphone control until the Behritones were giving me 83 dB on the meter.

Then I ran a measurement mic into an aux input in Pro Tools, not going out anywhere, but with a Waves PAZ analyzer on it. I set the sub trim to get as close to flat low end response in the room, with the Monitor A JBL pair on too. Close to all the way up is where it ended up.

I set the dim at a good dim spot - around 9 o'clock.

If I mix with headphones, I plug them into the Lavry.

The Behritones had to be run unbalanced out of the Aux, with a 1/4" TRS stereo plug to two RCA plugs "insert" cable.

The system works great, and I get equal volume when switching between monitors at average mixing volumes, making tonal comparisons better.

I considered building a passive balanced switch box with attenuation, but that would eliminate the sub control. The Radial box is unique in that it is a passive circuit, through the main L/R signal path, but with active buffers to handle the sub's mono fold-down, and for the headphone amp. Not many boxes on the market like that. It is really useful to be able to switch the sub in and out, while listening to any of the 3 monitor pairs.

Before I got the Lavry, I bought a 10K stepped attenuator, to switch out for the main pot. WAY too big to fit in the box! That would be an improvement, but would require its own separate box, perhaps mounted just below or next to the Radial with the leads running through a hole into it.

Now that I have the Lavry, I intend to improve the MC3 by eliminating all of the pots. I'll pull out the trim pots, leaving them set exactly where they are as I calibrated them, measure their resistance at that setting, then buy resistors of those exact values to solder into the board in place of them. The Monitor A and the Master pots will be replaced with a simple jumper, since they are set all the way up.