Rolls MB15b Promatch 2-Way Stereo Converter

This is being used in our computer audio 2.1 setup. (1) pair of wall mounted NHT Superzeros, (1) Denon AVR 1907 connected with optical to our computers output, (1) Rolls Promatch MB15B (been using it for a year or two already), (1) Crown XLS2000, (1) Infinity 1262W in a 4.6cu ft vented box we built tuned with an F3 approx 21hz. The Rolls Promatch doesnt appear to add any distortion or hiss or feedback and most importantly it solved our issue of low output. Sound quality of the Rolls Promatch? To my ears it does not alter the sound in anyway. No distortion, no hiss, no feedback. It is a well designed piece of gear. Using a Crown XLS2000 to power a single 12" Infinity Subwoofer in a 4.6cu ft vented box we made. Before the Rolls Promatch, I had to turn the Crown gain up all the way to get substandard output from the subwoofer. After reading recommendations that said to get one of these... I ordered one. Let me tell you something, this Rolls Promatch brought our subwoofer to life!!!! Connected an RCA from the Subwoofer preout on the Denon AVR 1907 to the input on the Rolls Promatch. Connected an XLR cable from the Rolls to the Crown XLS input. BOOOM!! Now we keep the Crown gain at about 2 oclock. Sometimes we have to turn the Rolls Promatch down because the subwoofers output overwhelms the audio coming from the pair of NHT Superzeros. If you are mixing consumer audio receivers with pro audio amplifiers you should invest in one of these. Even the newer pro amps that claim to have a switch, to switch between pro audio or consumer input voltage, dont work as well from the reviews I read. You have a regular home audio/video receiver and you are using a pro audio amplifier? Get one of these if you want to use that power you paid for, otherwise the amp is barely putting out any watts because the input signal to the amp is too low. Side note, if you are like me and you have a 2000 watt amplifier connected to a $60 subwoofer that only handles 300ish watts, dont turn it up too loud playing extended bass notes because the voice coil will start to smoke. I was a car audio bass competitor 20 years ago. I have just a little experience with overheating voice coils (playing extended bass notes at the transfer function of the vehicle +10hz after loaded with pressure, for the SPL meter light tree :) I did hit 154.4 db though with 1400ish watts RMS with (2) Crossfire entry level 15"s in a 10cu ft vented box (play more than a few seconds and they would blow).

Perfect match box for audio connections. The price is right for an active audio converter.

This box has an excellent 3.5mm stereo audio to Dual Balanced XLR output, but when you use the RCA inputs, it has bad grounding and the hum from the XLR to RCA side affects the RCA to XLR side. Presently I'm only using it to send 3.5mm to a pair of XLR outputs. I'm using a Scarlet 2i2 for the computer's balanced stereo in and out. So it doesn't handle a computer using stereo 3.5mm to RCA converter cables well. If Rolls replies, I'll add a star back on.

This is an excellent product! I have a Marantz SR-7010 AV receiver paired with a Crown XLS 1502 Drive core power amp..I could not get the full potential to play to my speakers so i got this to see if it would make any difference and BOOM!! this thing brought my speakers to life..even set at half way now on my power amp my speakers are insanely loud...whereas before i would have my amp at full tilt and nothing spectacular..this is definitely worth the money if you want to match Pro Gear with Home Theater equipment..i highly recommend it :)

Got my MB15b in the other day. Opened the amazon box to find the device, power cable, and a small information pamphlet just sitting in the box with my other items. They weren’t packaged in any sort of way, and one of the small rubber feet was missing. Aside from the terrible packaging (or lack of) I really like the product. I have my Numark Mixtrack Platinum controller hooked up via RCA, and use the xlr output to send signal to my Cerwin Vega CVE 18 and CVE12 powered speakers. Works great. Rca to xlr cables worked well but I got a lot of signal interference. That went away as soon as I switched to this. Wish I had a power switch and a ground lift, but for the price it’s great.

I use this for two applications. I have a pair of powered DJ speakers and a powered sub that all use XLR connections. Unfortunately, my DJ controller only has RCA outputs. For several months, I have them connected thru XLR to RCA cables. Once I connected the Rolls Promatch, there was a big jump on volume! Suddenly I have more headroom. After a few hours of playing, I decided to try it on a second application. This time a pair of powered studio monitors (XLR) and a home audio subwoofer (RCA) connected to a laptop via a cheap USB interface (RCA) using "Y" connectors. Again, after adding the Promatch to the signal flow, there was an increase in volume even if the level knob is in the 12 o'clock position. I think this is the default "0" position. If you turn it past 3 o'clock, you will hear distortion or clipping! So far, I have used only Channel 2 for both applications. And no more "Y" connections since it has both XLR and RCA outs on the same channel. A couple of things that I wished it had were a dedicated "on/off" switch and possibly move the inputs from the front to the sides so no cables to hinder the operation of the level knobs. This little contraption has saved me from purchasing a very expensive DJ controller with XLR outs and matching powered sub for my monitors.

I love listening to EDM, Dubstep and other types of music with heavy bass lines throughout the day. Even after upgrading my subwoofer driver to the Dayton DCS385 (see separate review) I felt as though the bass was still a bit anemic. This little rascal solved that problem! Works great and allows me to dial up or dial down the bass coming from my subwoofer depending upon my mood, listening volume and type of music. Want to shake the floor and rattle the pictures off the wall? Turn up the output! Want to relax to some classic jazz? Turn the output down. An inexpensive alternative to buying a more sophisticated electronic crossover.

Using this to take two balanced XLR outputs from the Behringer Wing mixer to stereo line level for our livestream gear. On the other side, taking line level output from a PC to balanced inputs on the mixer. Great piece of gear!

Este aparato es lo que todo productor de audio para video necesita. Todos usan cables convertidores entre equipo profesional y equipo casero y terminan con audio de mala calidad. Yo lo uso para mandar la señal de mezcladoras directo a un switcher de video, laptops u otros equipos que no cuentan con entrada de audio profesional, específicamente para hacer streaming y me resulta excelente.

I have two subwoofers in the theater room with balanced cables to them in the wall. The equipment rack has audio processor with XLR output as well but I want to use miniDSP which has only RCA connections. So I'm using ROLLS MB15b Promatch to convert XLR input from processor to RCA, feed it into miniDSP and its two RCA outputs go back to ROLLS which converts those back to balanced outputs sent over cables to the subwoofers.

Massive improvement

a must if you want loud shaking sound to hook up your Crown xls amps, works great, just need xls m/f cables and rca cables, makes your speakers Rock!,,,,,,,buy one!, only takes awhile to come!

The Rolls MB15b makes a good interface between consumer grade electronics and Pro audio gear.