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Roland M-48 Live Personal Mixer

This "infinitely customizable" personal mixing system is robust, intuitive, and impressive.

The practice of providing musicians a control surface with which to adjust their headphone mixes first became commonplace in the recording studio context. The first generation of personal mixing systems typically provided for the artist to have control of 4-8 channels of audio, which commonly derived their signal from sub mixes on the studio console. Such systems generally used analog signal distribution and proprietary cabling and connector schemes. They served their purpose in the studio setting but would have been cumbersome and of limited usefulness outside of that context.

Over the past few years, a small handful of manufacturers have brought purpose-built personal mixing products to the marketplace that use digital audio bus technology and twisted pair cabling to provide artists the capability to control their individual in-ear mixes. These systems, most of which appear in 8-16 channel configurations, have gained widespread acceptance, particularly in the house of worship market. I have, however, always considered the low channel counts to be a limiting factor as I mixed in-ears for a contemporary worship service for about three years, and it almost always seemed as though the drummer wanted to hear just a little more hi hat or the singer a little more reverb. This is understdandable given the degree of ambient attenuation inherent with in-ear monitors. By the time one considers individual drum channels, ambient mics, and effects, even a 16 channel system can be very limiting indeed.

As a V-mix user and reseller, my interest was piqued when I heard that Roland would be adding a personal mixing system to their product line. I became considerably more interested as I began to learn about the system’s capabilities.


RSS by Roland’s new personal mixers operate on the same REAC (Roland Ethernet Audio Communication) platform as their digital snakes and consoles. The system components include the M-48 personal mixer and the S-4000D REAC splitter (basically a gigabit PoE Ethernet switch which provides for power, signal, and control distribution for up to 8 units). These components must be combined with some iteration of the digital snake for A/D conversion, and may be operated in a standalone configuration with PC software control via the serial port on the snake, or may be used in conjunction with RSS by Roland’s M-400 or M380 digital consoles, both of which have a series of M-48 control pages in their software.

The most noteworthy feature of the M-48 system is that each group knob on each mixer can be configured on an individual basis to derive signal from any combination of the 40 sources on the REAC bus. This allows for each musician’s mixer to be laid out according to his or her preferences, making for an infinitely customizable solution.

The M-48 mixer has eight rotary encoders with LED level indicators which provide for control over various parameters for 16 stereo groups across two layers. Volume, pan, and reverb send level, as well as a three band EQ with a sweepable midrange frequency, can all be set on a per-group basis via the encoders. The M-48 additionally includes a built-in ambient microphone which can be added into the ear mix, a limiter, a local aux-in (for metronome, etc…), and stereo auxiliary outputs. Headphone outputs appear on both a 1/4″ and 1/8″ connector, and an attenuation adjustment is provided. The auxiliary outputs can feed a wedge mix or a personal digital recorder, which would allow the more sophisticated user to record practice tracks. An optional 80 Hz or 100Hz low pass filter on the aux output bus can additionally be engaged in the control software, allowing for selected channels to be routed to a low frequency transducer (i.e. butt-kicker) without the need for additional processing. Finally, each M-48 includes the facilities for 16 locally recallable presets.

In Use

I received six of the M-48 mixers and one S-4000D Splitter the day before I was to deploy the system for the evaluation. Upon unpacking the pieces, I observed that the build quality of the M-48 seems quite good compared to the other systems I have worked with. Consistent with the rest of the RSS product line, the M-48 and S-4000D are outfitted with Neutrik Ethercon connectors, making for robust and reliable interconnection. A microphone stand mount is included with each M-48.

I connected all six of the M-48’s to the powered ports on the S-4000D splitter, (Ethernet cables with a straight or crossover pinout maybe used as the S-4000D is able to auto-switch), then patched the S-4000D to the REAC B port on my M-400 V-mixer.

After entering the M-48 setup screen, it took me a few minutes to wrap my head around the signal flow paradigm. I discovered that each M-48 is a 40 channel mixer (with inputs derived from the 40 sources assigned in the REAC B output patch bay),. Consequently, each input on each M-48 mixer can derive signal froma single channel or from a mix of several channels with relative levels determined in the M-400’s M-48 control screen on a per-unit basis. So, for instance, the drummer’s mixer could be configured to provide individual control of eight drum microphones with one encoder controlling a mix down of all the BGV channels, while at the same time the background vocalists’ mixers could be set up with one encoder controlling a sum of drums, while providing individual control over vocal channels. Because I did not have detailed input lists from the bands that would be performing at the next day’s concert, I set up a generic patch on one of the M-48’s, then copied all parameters to all of the other mixers.

The application was a back-to-school concert at my local university campus featuring two local bands. Monitoring was a combination of wedges and in-ears. For the wedge mixes, I patched the aux outputs from the M-48s back into input channels on my S-4000 snake unit, which was patched to the REAC A port on my M-400 V-mixer. (The M-400 was handling FOH and monitor duties.) I routed those inputs to the appropriate aux busses on the console, which were feeding the wedge mixes. This allowed me to have the benefit of the console’s graphic EQ facilities for the wedge mixes and the ability to control stage levels if necessary.

The headliner was first to sound check, and because of the time crunch, we stuck with the patch I had established the day before. The musicians picked up on the interface relatively quickly, and were highly impressed with their ability to customize their mixes. After the sound check, I saved a preset on the M-400. In the current software revision, this action saves all the parameters in the M-400 but additionally writes a file to the USB memory that includes a snapshot of all 16 presets from each of the connected M-48’s. (This is an extremely powerful feature in most any context.)

The opening band had a similar experience with the M-48’s, providing more positive feedback. After they played, I simply recalled the headliner’s preset and we were off. The concert went very smoothly and the band kept the stage levels in check surprisingly well.


In summary, the RSS by Roland M-48 is the most powerful purpose- built personal mixing system I am aware of on the market today. The setup is infinitely customizable and the sound quality is excellent. I fully expect that it will grow rapidly in popularity, being deployed in conjunction with V-Mixing System and in stand-alone configurations. The system is a viable alternative to all of the other platforms, and I believe is robust enough for portable/touring use. With added sophistication, however, comes increased opportunity for setup error, so potential users are advised (as in all digital console applications), to take the time on the front end to build the patches. The M-400’s M-48 control interface could stand to undergo a few minor tweaks but is fairly straightforward once the user has a grasp on the signal flow. All in all, in my opinion, anyone on the market for a personal mixing system should seriously consider the M-48 system by RSS.

Ben Williams is owner/engineer of Essential Audio, a Nashville-based live sound reinforcement, system design, and integration firm.