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Review: SM Pro M-Patch V2

A simple monitor controller just got better with swappable encoders.


17 October 2013

The M-Patch V2 is one of those devices that you may not realise you need at all but once you’ve tried it, you won’t want to be without it. Following on from the success of the original M-Patch, the M-Patch V2 offers the high-quality passive attenuation of the original version but in a larger package that’s easier to use and incorporates several improved features. Some apparently as a result of suggestions from users.

An Australian design, the M-Patch V2 connects between an audio interface or mixing console and the monitor amps/speakers to provide analogue volume control and alternate source/speaker selection. For DAW use without a mixing console the M-Patch V2 allows for clean analogue level attenuation rather than potentially degrading digital attenuation. For DAW use with a mixing console it offers the convenience of placing the level control in a more accessible position. In my situation I use a fairly large analogue console but sit at a desk with screens, keyboard and mouse; the mixer is off to the side. So I’m forever leaning over to adjust the monitor level. Aside from the small amount of physical exercise this gives me it’s inconvenient and often means leaning across customers to get to the mixer. The M-Patch V2 has allowed me to place the level control in front of me, within easy reach.


Physically the V2 is 2U high compared to the 1U original and this means there’s plenty of space for the controls. It looks a bit like a clock radio with its rounded sides but it’s strong and well built. The main level encoder is large and everything is chunky, easy to see and grab. A couple of stick-on rubber pads are included in the box to stop it sliding backwards when you push a button. A rack-mount kit is included but I would imagine most users would use it as a stand-alone unit, unless the rack is within easy reach; the ability to have the level encoder close at hand is one of its best features. The rear panel has two combo XLR/jack connectors for the main stereo input, two RCAs and a 1/8-inch socket for auxiliary inputs, and two pairs of XLR output sockets for connecting amps/speakers.

As well as the convenience of choosing where to place the controller it has several other handy functions that can be used in a variety of ways depending on the specific set-up. Because it’s a passive device there’s no way it can colour the sound and the V2 version comes supplied with two interchangeable rotary encoders; one is continuously variable, the other operates over 12 stepped positions for easily repeatable settings, and comes pre-installed. The stepped attenuator is specifically designed for the M-Patch range with 470Ω film resistors that have a high accuracy of ±0.1% to keep the impedance to the lowest level SM Pro could in a passive system. A level of accuracy standard variable attenuators can’t match. It’s a doddle to change between them with only four screws and a connector to deal with. 

It’s also a speaker selector for those who use more than one set of monitors. I found the Aux input convenient for the CD player that otherwise takes up a couple of console channels. Having the Mute button close at hand is great for killing the sound quickly. And it has one my favourite functions; a stereo/mono switch. Currently I can listen in mono via software or by centering the playback channels on the console, but having the switch at hand is much easier and I found I was using it more often — it’s good to regularly check stereo work to see how it holds up in mono.


All the functions mentioned so far are passive and work without any power connected to the unit, but if the power supply is connected then you get indicator lights for input/output/mute selection status. Plus, the headphone amp works, and it works well; sound quality is good with plenty of power and a separate volume control. I liked the way selecting Mute kills the main outputs but not the headphones, making it handy for a quick check with cans. Having the headphone amp means the M-Patch V2 now controls all the main monitoring options, near-fields, wall/large monitors and headphones. 

The M-Patch V2 quickly found a place in my set-up and while I used it as a speaker selector and volume control, there are lots of other points where clean level control is required and others will no doubt find different ways of configuring it to suit their own circumstances. This is a very handy device at a good price.


SM Pro M-Patch V2
Passive Monitor Controller



    Sound & Music: (03) 9555 8081 or info@sound-music.com

  • PROS

    • Swappable stepped or continuously variable encoders
    • Stereo/Mono switch a big help
    • Selectable dual inputs & outputs
    • Good price

  • CONS

    • None


    SM Pro’s V2 passive volume controller could and should find its way onto every studio desk that currently doesn’t have good monitoring control, or could do with a highly accurate, repeatable set up.

STEP UP: The V2 version comes supplied with two high quality, interchangeable rotary encoders — a continuously variable model, and a 12-step variant that’s great for locking in consistent monitoring levels.

CHECK FOR MONO: The stereo/mono switch is handy for regularly checking stereo work to see how it holds up in mono — a good thing.


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