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E.T.I Sound Systems in Huntington Park, CA is much better known as B-52 Pro-Audio or, simply B-52 as most know them. B-52 was founded in 1979 and has been bringing serious value to the market for well over 20 years now. What many don’t know is that B-52 is 100% MADE IN THE U.S.A.! Very few loudspeaker manufacturers build all their components themselves; B-52 is one of the few who does. In this manner they can oversee every step of the entire manufacturing process.

When Peter at B-52 called me, he asked that I give their ACT-18 powered subwoofer along with the matching ACT-18 slave unit a real good workout. In fact, when I later spoke with Avi, he flat told me to be brutal! Throw at them whatever I wanted and write up exactly what the results are…now how can you pass that up? And does Avi really know how sadistic I can really be?

The ACT-18 is a relatively compact trapezoidal shaped enclosure constructed of 3ž4”, 18-ply Baltic Birch measuring 24”W X 33”H X 22”D. It weighs in at almost 110lbs, but it is quite easy to move since B-52 provides a tilt back rear handle and recessed wheels. Not only do they provide a pole mount, but they even include a 20” pole for mounting your top cabinets above them! Also included is recessed handles on each side of the cabinet.

The horsepower comes from a digital amplifier weighing a mere 6lbs and delivering 800 watts to the ACT-18, and a total of 1200 watts when also powering the ACT-18S. The amp module also contains the processing for the system and since it’s a digital amp, the current draw is minimal. More on current draw later. The 18” driver as noted, is built by B-52 and incorporates a cast aluminum frame, 200 oz. motor structure, a bumped and vented back plate for long excursion with a 4-layer, 4” diameter polyamide voice-coil. Four vents are on the front baffle configured horizontally below the driver. A 16 gauge perforated metal grill keeps the driver protected.

The ACT-18S is identical to the powered unit in appearance, though the rear panel has a simple Neutrik input rather than the amp module. Weight is just over 100lbs.

Hooking up the unit is a snap! XLR balanced cables from your equipment to the only inputs on the unit. From there we have choices. The first, being able to run the outputs full-range to another amplifier or powered speaker system. The second is what most will use, the high-pass outputs. This gives us a 120Hz crossover and relieves the burden of reproducing the power robbing bass from your main speakers/amps…after all, that’s the whole point of bi-amping! The first method however is quite useful for daisy-chaining more ACT-18’s when you feel the need to break stuff! Thankfully, B-52 has provided all balanced XLR connections.

Now we use a Neutrik equipped speaker cable to run from the amp module to the ACT-18S slave unit. There’s a switch just above this output for turning the external speaker On/Off. While we’re around back, now is a good time to make sure the gain is all the way down and to set the Phase switch to 0. It’s a simple 2 position switch allowing you to reverse the phase 180* if need be. Attach the detachable IEC power cable and after powering up the front end hit the switch and the power light should come on as well as a lit On/Off rocker switch. There’s also a protection light in case you end wiring something wrong. Evidently, it also lights up when/if the amp is overdriven or overheats…fugetaboutit! I tried quite hard to do just that…it isn’t gonna happen with this bad boy! The only time I saw it light up is when you fire the unit up…and when I checked the protection circuitry as noted later.

I hooked the ACT-18 system up from the mixer outputs into the unit’s inputs, then using the high-pass outputs I ran into a popular 300wpc amplifier powering some well known 12” 2-way cabinets. My initial impressions were not real favorable. In fact, while the unit had simply incredible output, I found that output to be quite muddy sounding. Hmmm…ok, it had been a very long day and perhaps I should take this on with a well rested and clear mind the following day.

The next morning I took the time to properly integrate and balance the system and my oh my…What a Difference! I originally had the level set to around 3pm and when I was done tweaking I found optimum results at a 1pm setting. I lost virtually no thump, yet the definition was improved immensely. Ok, now we’re on to something here.

I ran a great deal of material through the system including some bass discs to limber up the surrounds and to tick off the neighbors. I was quite pleased with the sound I was receiving and especially pleased with the output. After a few hours of break-in and a lunch break, I headed back down to find how well this unit responds to what will likely be thrown at it. The result was good tight hard hitting bass. I started to add some bass boost from the eq and found the B-52’s simply ate it up and spat out even louder bass. Ok, let’s see how it handles stupid amounts of boost…quite well! The compression and limiting circuit simply keeps the peaks from getting any louder and brings the average level up while keeping it clean ….cool! Throwing even more at it is just more of the same. This was at levels nobody should ever be using. While the processing kept it clean and loud, the peaks were no longer very dramatic…and think of it this way…when you have good bass to begin with you needn’t rely on heavy handed bass boost! While many designs use the same kind of processing, many will still go into very heavy distortion. B-52 has this covered very well. When the amp reaches it’s limit, the compression/limiting keeps things in check making this a very hard system to overload or make distort…but let me try anyway!

Throwing a couple of bass CD’s in, putting the player in flip-flop mode and setting the bass boost & volume level on “stun”, I went next door to shoot the bull with my understanding neighbor. Thinking I’d hear the sounds stop after awhile when the amp overheated…and I’ve thermalled many fine amplifiers with this abuse, I was surprised that it only stopped when both discs were completed…and the amp module was only warm. Needless to say, thermal protection is NOT anything you’ll ever need to worry about with the ACT-18 system. This system just continues to throw out deep, tight, hard hitting bass without any worries.

For my next assault…err, I mean test, I used the system as described above for an after school dance and I had several hours of extra time to extract some hard numbers. I first used just the single ACT-18 unit without the slave unit and I must say it does quite well alone. B-52 advertises a 30Hz subsonic filter at 36db/octave. I found the unit to be -2db down at 30Hz, though this is really nitpicking as it does a superb job in this regard and falls within their rated specs of +/-3db 30Hz-120Hz, though I found the unit to be exactly -3db at 120Hz.

While it sounded quite good, I was also surprised somewhat by the solid SPL the unit delivered. While B-52 doesn’t give a distance for their maximum peak SPL, I found the unit to deliver 131db @ 1M...VERY impressive performance from ANY subwoofer, let alone a powered sub of modest size. Naturally, I wanted to add the slave unit and couple them for that cardiac arrest feeling. The complete ACT-18 system didn’t let me down…try 137db peaks when running both and coupled side by side! To put that into prospective, no other powered subwoofer system I’ve measured has come remotely close except the very large and expensive Mackie Fussion system. It does better this figure and well should at more than double the price. More impressive is that I ran the entire system off a single 20A circuit and had plenty of current.

In this configuration, the bottom end was easily capable of providing excellent low end response for the room I was in. After a couple of hours of pounding the youngsters silly, the amp was only slightly warm to the touch and I came away with a good confidant feeling about this subwoofer system. I also found that these units are extremely easy for almost anyone to move around as they’re very well balanced. Obviously, B-52 knows you have to move these bad boys around and have made it very easy to do so.

The next event was for a small gathering of around 80 adults in an average sized room. I was curious how a single ACT-18 would perform and while I brought both, I never found the need to hook up the slave unit as it provided adequate low end for the mostly classic rock these folks requested.

For the next event, I configured the system slightly different by using them in a more conventional manner, pole mounting the tops above the subs on each side. This again worked adequate in a much larger than average sized room, though personally, I’d opt to couple the subs whenever possible just for the extra kick in the gut. Of note, I found later the entire sound system was running off a 15A circuit and again, no problems. The digital amplifier is very efficient in the ACT-18.
I was curious as to how these units stacked up against some other powered subs on the market and my local retailer was more than happy to allow me to use his demo equipment…though as it turned out, I had to take the B-52 system into the store as that was all he had in stock.

In comparison with the EV SXa-180, the B-52 ACT-18 sounded (and felt!) much stronger. SPL tests confirmed what we were hearing with a minimum 5db to 6db advantage across the board. The owner was curious how 2 of the EV’s would stack up against a single ACT-18 and the only other unit he had on hand was on hold for a customer, however, it had been out of the box once before so curiosity got the best of him…ok, I egged him on quite a bit! Using two of the SXa-180’s coupled was “almost” equal to the single ACT-18. That’s impressive! I will note however that the 4 of us present felt the SXa-180 has a slight edge in definition. It’s difficult to tell on modern pop music, but on finely recorded modern jazz you can tell the difference, though it isn’t something most mobile DJ’s will ever worry about for the intended application.

Next up we tried the new JBL MPro 18” powered sub and found largely the same thing. While there weren’t two powered versions to try, their powered & slave unit fell short in numbers and gut punch. Definition seemed even with pop music, but with finely recorded modern jazz, the JBL system was very slightly better. Let me say that both of these subwoofer systems are quite good and this takes nothing away from them at all…it merely shows that the ACT-18 is capable of much more kick.

Next we tried a pair of Mackie SRS-1500 trade in units and they were simply outclassed by everything else. While unique in their day, they don’t really compare in any way to the new class of powered subs and definitely not the ACT-18. Running 2 of the SRS-1500 subs coupled produced a dismal peak of 126db@1M, almost exactly what I’ve previously measured those units at. Definition was also somewhat muddy in comparison. This mud only increased with volume and we tried tweaking them quite a bit to improve their sound…it simply wasn’t in the cards.

The dealer was holding an ace up his sleeve though and when I thought we were done shaking the store windows; he sent one of his employees to retrieve his ace from the back room. In rolls the brand spanking new Mackie SWA1801…holding out eh? We were all curious to hear this new beast as the specs look to be incredible! While he was giving the B-52 accolades for offering such a stout performer at a terrific price point, he was also licking his chops at the certain humiliation he felt it would shortly be suffering from….

Much to his chagrin, it was the new Mackie that was humbled! Granted, it’s a remarkable step up from their previous unit, but it fell well short of its published specs and short of the numbers the ACT-18 delivered…and delivered for much less money too! He’s looking at possibly adding another speaker line and B-52 has his full attention now.

After spending an entire afternoon bombing away, that test session convinced me of what I had been suspecting for sometime now. The B-52 ACT-18 is the real deal! Never once have I found the amp more than just slightly warm to the touch and I had to resort to wiring up a dead short to make sure the protection circuit works…it does. You’ll want to take the time to properly integrate the ACT-18 into your system…and don’t get heavy handed with the level control as I found out it simply wasn’t needed and only makes the sound muddy …here’s a case where less is more! Only once did I have the gain set to 2pm and this was in a very large room. I never found the need to switch the phase to 180*, though I do recommend you try this for yourself as I tried it each time out.

Finally, I was curious how the ACT-18S unit would work out when powered in a conventional manner, meaning external crossover, amplifier etc. I took the unit with me to a large corporate holiday party where I had plenty of time to setup. I ran my larger system I use for these events, but after coming out of the summed mono output of the crossover I went into an amplifier providing 2400 watts in bridge mode. I was pleased to find the ACT-18S very capable and highly dynamic to be sure. I was able to find the limits though and when I really leaned on it the driver bottomed out very audibly. No problem, it was overpowering the unit by quite a margin since it’s rated at a healthy 1000 watts and I was likely sending peaks of nearly 3 times that into it! Backing off slightly made for a very dynamic hard hitting subwoofer.
Of interest is while my peak number was higher in this configuration, the average levels when powered by the ACT-18 was higher when running it at very high volume due to the compression and limiting that unit provides. At any rate, it convinced me that it’s a good solid well designed unit.

B-52 provides an excellent warranty. 5 years on the drivers, 2 years on the digital amplifier module and lifetime on cabinet construction! Considering my dual bass CD torture test and numerous maximum SPL testing I had no problems, I doubt anyone else will when used normally…though it’s certainly good to know they’ve got you covered.

Most know I’m big on product that delivers excellent results on a minimal investment, or, the “best bang for the buck”. While there are many fine powered subs on the market, you should definitely “get your ACT together” and audition the ACT-18 system. Clearly, the B-52 Pro-Audio ACT-18 system delivers the “best bang for the buck” with nuclear assault force!

Bob Dietrich
ProDJ.com Equipment & Gear Moderator/Review Staff