Fast FactsApplications: Installation
Key Features: Four-channel; Class D; soft knee compressor; limiter; high-pass filter
Contact: Rane at 425-355-6000, www.rane.com. Those of you who have been reading my reviews over the years probably know that I am a Rane fan. They have quietly and consistently produced high-quality products for the pro audio market. While they have a reputation for install equipment, I have a number of their products in my live sound arsenal that I rely on steadily. At the same time, Rane has proven to be a valuable resource to our industry, providing a broad range of useful technical data in manuals and on their website. In fact, the manual for the MA4 comes with lengthy treatises on constant-voltage audio distribution systems and sound system interconnection.
Single space, multichannel amplifiers are still something of an oddity in our industry but I would suspect that Rane is one of a few companies with the capability to make this format a staple. Thus, my curiosity was piqued to examine the new MA4 ($1,399) from our friends in Mukilteo, Washington.
As mentioned, the MA4 is a single rack space, four-channel amp that utilizes a switch mode power supply to provide 100 watts per channel (4 ohms or 8 ohms) output. The whole unit weighs in at eight pounds and it measures 9.25 inches deep. As is characteristic of Class D amps, the MA4 is purportedly very efficient. The universal voltage supply (85 – 260 VAC, 50 Hz or 60 Hz) is power factor corrected and has a claimed low inrush current. The MA4 has a host of valuable features like remote turn-on, load sensing, remote fault reporting and redundancy switching (where an alternative primary amp channel or secondary amplifier can be employed to automatically engage when a fault is detected in the primary amp channel). Additional features include remote DC level control (when partnered with Rane’s VR2 remote), a load dependent limiter, a soft-knee compressor, a downward expander, and a high-pass filter (20 Hz, 40 Hz, 60 Hz or 80 Hz).
The front panel of the MA4 has a four-segment headroom meter, a limit indicator, a compressor indicator, an expander indicator and indicators for ready, load and fault for each channel. While these indicators may seem rudimentary on the surface, they are actually fairly in-depth. For instance, the load indicator is off when the amp encounters loads of greater than 16 ohms, it turns on when the load is between 2 ohms and 16 ohms and it flashes when the load is below 2 ohms. The MA4’s rear panel has inputs (each with a sensitivity attenuator), outputs, remote DC level ports, and external amplifier inputs (for use with internal automatic redundancy) on Euroblock connectors. There is also a bank of DIP switches to control parameters of the compressor, the expander, the high-pass filter and Master/Slave status. If all this isn’t enough, consider the fact that the MA4, when used in tandem with Rane’s MT4 multichannel transformer, can drive 70V or 100V distribution systems.
As with previous Rane products I’ve encountered, the MA4 has a marvelous fit and finish. The chassis seems rugged and the look is very professional. At first, I tinkered with the amp in my studio and then I temporarily installed it in an exercise studio with two independent zones (each with two 8 ohm speakers). In my studio, the amp sounded clean and responded well to a variety of program material. The MA4 negotiated transients and bass-heavy content in a way that was impressive for an amp of this size. Engaging the HPF at 60 Hz or 80 Hz cleaned up some mud from a headset mic with a cardioid element but I would probably leave it set to 20 Hz or 40 Hz if the amp was being used for playback music without subs.
In the exercise studio, the MA4 was used for CD/MP3 playback with two pairs of full-range cabinets, each pair located in a different room. Admittedly, the MA4 was not presented with any stressful program material in this simple application, so there should be no surprise that it excelled in what it was asked to do — provide four channels of good sounding audio. It was comforting to know that the internal load-dependent limiter was at the ready. At the same time, I was able to utilize some of the onboard features like the previously mentioned high-pass filter, the internal compressor (threshold is set at 10 dB below the limiter threshold and ratio and attack are fixed at 3:1 and 1.5seconds) and the expander (-70 dB FS threshold). While the MA4 tackled this application with no problems, more complex scenarios are where I think it would truly shine. This unit cries out for assignment to critical paging, home theater and multizone speech or music applications. Were I to have installed the MA4 in a critical permanent setting, I would have been very confident that, with it’s internal protections and internal/external automatic redundancy, it would offer many years of un-interrupted service.
With an ample power-to-size ratio, distribution capability, efficient operation, internal protections, a variety of smart features and external controls, the MA4 is ripe for use in schools, restaurants, corporate offices, worship houses and even high-end residential applications. If it is anything like other Rane products I’ve used in the past, it should prove competent and durable. With a list price of $1,399, it isn’t a “budget” piece and it should be applied accordingly. At the same time, it would cost much more (in money and space) to equip a client with all the tools to do what the MA4 does.