REL Acoustics Stadium III Sub-Bass System
Sounding Off The Deepest Notes.
Review By Rufus Smith
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  My introduction to the REL line of sub-bass systems actually came about by accident. I was at HE-2001 and was visiting with Craig Oxford of Nearfield Acoustics, makers of the highly regarded Pipedreams. Nearfield was introducing a new "smaller" version of the "Pipes" that was code-named the "924". I was really intrigued with the loudspeaker so Craig made arrangements for the show pair to be sent to me after the show. However, there was a problem, the smaller subwoofers that were being designed for the "924's" were not ready and I did not feel like I had the room in my listening room to accommodate the larger 18-inch "depth charge" woofers that are part of the larger Pipedream systems. Craig did not feel that this was a problem as the "924's" were designed to be used with any commercially available subwoofer.

While discussing the various subwoofer options with several of my fellow journalists, the name REL kept coming to the forefront. After returning home, I placed a call to Sumiko, REL's US importer to find out more about the REL subwoofers. In my conversations with Terry Medalin of Sumiko, the first thing I learned was that REL does not consider its products to be subwoofers but rather sub-bass systems. According to REL, a large number of "full range" loudspeakers cannot reproduce the low bass frequencies found in most music. These low frequencies are necessary for the accurate reproduction of the original recording and go a long way in helping to impart ambiance that brings us closer to the "real thing". REL feels that the best way to add these critical bass frequencies is to use a properly designed sub-bass system. This system should not only have the ability to cleanly reproduce these low frequencies, but it will also integrate cleanly with the main loudspeakers so that the whole system speaks with one voice that is more natural sounding. The end result, according to REL, is a system that will offer the listener much greater fidelity.

Terry felt that the midline Stadium III would be a perfect match with the Nearfields so he arraigned for me to receive one for a review. About a week later, I arrived home to find quite a large box strapped to a pallet literally blocking the door to my house. After my wife and I lugged the thing into the house, I placed a call to Terry to tell him that it had arrived. During the call, Terry informed me that he had arraigned for Bill Pugh, their east coast representative to give me a call to assist with the setup. Bill was going to be in the Charlotte area the next week meeting with a new dealer, so it made perfect sense for him to stop by and assist me with the setup. This was a pleasant surprise as I had met Bill several years earlier and found him to be a first class individual. I welcomed the opportunity to visit with an old friend that I had not seen in several years.

The Setup
After finishing my conversation with Terry, I proceeded to unpack the REL. The Stadium III is a 110-pound rectangular box that is finished in a beautiful cherry veneer. The box measures 23 x 22 x 15 (inches). Inside, you will find a 200-watt mosfet amplifier that contains a self-limiter to prevent overloading the downward firing long-throw 10" heavy duty "Voit" driver. The enclosure is super rigid. The tried and true "RAP" test produced nothing but a dull thud. The secret to the REL's success is the proprietary "Accoustic Resistive Matrix" method of loading the box.

According to the literature accompanying the unit, ARM is a refinement of basic reflex loading. The ARM structure essentially divides the box into a series of separate cavities. Each cavity is allowed to vent into the adjoining cavity in a very controlled and resistive way. The "Voit" driver initially sees a small volume of air directly behind it. As the bass frequencies become lower and lower, the loading changes as the other cavities come into play. As a result you get smoother, tighter and much more extended bass response than you would expect from a single 10-inch driver and a small box. As a result, the Stadium III is said to extend down to 16Hz.

The Stadium III offers the user a degree of flexibility that makes it easily adaptable to almost any room. This degree of flexibility will also allow the REL to seamlessly integrate with almost any loudspeaker there is. On the back panel you will find the power switch, a 15-Amp IEC connector, coarse and fine gain adjustments, phase inversion and the input connectors. It is through the coarse and fine gain adjustments that allow for setting the various crossover points. The range is from 24Hz to 106Hz. Two low level inputs (0dB and +12dB) via RCA's, a balanced high and low pass input via XLR's and a unbalanced input via a Neutrik Speakon connector are provided. The unbalanced input via the Speakon connector is unique in that it allows the Stadium III to receive its signal directly from the loudspeaker terminals of your amplifier. This is the preferred method of hookup as it allows the REL to receive the same identical signal as the loudspeakers. According to the REL's designer, Richard Lord, this allows the character of the bass in the two systems to be in perfect harmony. In addition, critical phase relationships are maintained and the system remains totally integrated. In addition, when using the loudspeaker level connection, the signal is not routed through an additional crossover before being sent on to the main loudspeakers.

Initially I set the stadium up according to the instructions provided by REL. First I hooked the REL up to the output terminals of the Pass Labs Aleph 1.2's that were serving as my reference at the time. I ended up with it located midway between the two "924" towers and pushed back as close to the front wall as I could get it. The "924" rolled off at 45 Hz so I had the crossover point set at around 60Hz. The REL seemed to integrate well with the Nearfield towers and I was a happy camper or at least I thought I was. A few days later Bill Pugh arrived and the trouble began (for me at least). It seems that Sumiko feels you get better performance out of the REL with it placed in a corner rather than centered between the loudspeakers. Like many other audiophiles, my listening room and family room are one and the same. A bookshelf unit that held our television occupied the only free corner in the room. So out it went (try explaining that one to your wife).

After moving the television and shelf unit, Bill began the setup by placing the Stadium into the corner with the control panel facing the front wall. Using "I Bid You Goodnight" from Aaron Neville's "Warm Your Heart" as a guide, Bill began by adjusting the phase setting to determine which position produced the louder bass. Once the proper setting was determined, he then began moving the Stadium out diagonally from the corner while listening for the greatest output and extension. Once the proper position had been determined, the process of adjusting the crossover setting via the fine gain control to reach the smoothest integration between the Stadium and the Nearfield towers. The best results were obtained with the REL crossed over at 32Hz, which was very surprising considering the "924's" start rolling off about 60 Hz and have a published lower end frequency response of around 45Hz. I am at a loss to explain it but the integration was absolutely seamless.

More Listening
As I mentioned previously, I was very happy with the initial setup. The blend between the main arrays and the REL was seamless to my ears. The bass had impact and depth, it just did not seem to go as low as I thought it would. The corner placement recommended by Sumiko allows the REL to properly pressurize the room. With the corner placement, the bass was not only tight and defined, it seemed to plummet to unheard depths. It was at this point that Bill introduced me to his ultimate torture test. He pulled out a copy of the soundtrack from the movie "Moulin Rouge". Track 13, "El Tango De Roxanne" is one of the most extreme tests of the capabilities of an audio system that I have ever seen. It starts out slowly and just keeps building and building. Bill told me that he had yet to hear a system that wouldn't clip when playing back this track at high volumes. Well, I am pleased to report that my system didn't pass the test either but Bill said it was one of the best he had heard. We played the track several times with the REL switched in and out of the system. With the Stadium III out of the system, the bottom octaves were missing as was to be expected. However, I was not prepared to hear a loss of air and space around instruments. Everything sounded almost anemic. There was a noticeable decrease in both the depth and width of the soundstage. At this point it became very apparent to me that having the REL in the system allowed the "924's" to operate full range. Freed from the chore of having to reproduce the lower octaves, the main arrays were allowed to breathe and do their magic.

The Bottom (Bass) Line
After listening to the Nearfield/REL combination for several weeks, I decided to try the REL with my reference WATT/Puppy 5.1's. I figured that this would be a more realistic test of the REL's abilities since the Wilson's go much lower than the Nearfield's, which are not really considered a full range loudspeaker. Putting the Wilson's into the system required a little fine-tuning of the Stadium's position and crossover points. The REL ended up about 1 inch closer to the front wall with the crossover point set at 28 Hz. The low-end performance of the Wilson's is world class, but with the Stadium engaged it became even better. There was a greater sense of space in all planes. Instruments had greater impact and were much more realistic sounding. Everything was improved. It did not matter where the instrument fell in the acoustic spectrum, the overall performance was greatly improved by the addition of the REL. There was never a trace of bloat and boominess that I have experienced with other subwoofers. With the REL in the system, the Wilson's seemed to operate with a sense of ease, which made them sound even more natural and effortless than they normally do. I really was amazed how much better the REL made a loudspeaker that is already considered "world class" even better.

Another thing that impressed me about the REL is its speed. Most subwoofers are slow compared to the loudspeakers they are used with. Not the REL, it has the speed to keep up with most anything out there. The REL has worked well with every loudspeaker I have matched it with. I also tried the REL with a variety of amplifiers. The REL seemed to take on the characteristics of the amplifier that it was being used with when it was driven from the amplifiers outputs. I don't know how it manages to accomplish that feat. All I know is that it does.

At $3,000, the Stadium III is almost a bargain considering what it did for my system. The REL took what was already an excellent system and made it even better. Highly recommended. Oh yeah, Julie I promise to put the TV back into the family room soon.

Specifications
Type: subwoofer wuithg built in amplifier and crossover

Driver: 10-inch heavy duty "Voit"

System Type: ARM loaded cabinet with ABC semi-tone variable bass filter. 65 litre

Lower Frequency Response: -6dB at 12Hz (in room)

Amplifier Input Impedance High level: 100 kOhm

Gain Control Range Low Level: 10 kOhm/80dB

Drive Unit Impedance: 8 ohm 

Mains Input Voltage: 115V at 50/60Hz or 230V at 50/60Hz, subject to country

Dimensions: 23.25 x 21.98 x15.37 (WxHxD in inches)

Weight: 110.23 lbs.

Finishes Black Ash, Cherry, Light Oak, Rosenut, Walnut (subject to country of sale)

Price: $3,000

Company Information
REL Acoustics Limited
North Road
Bridgend Industrial Estate
Bridgend CF31 3TP

Voice: +44 1656 768 777
Fax: +44 1656 766 093
Website: www.rel.net