The reason we changed the listings to not include the RMS designation in the MK3 line was due to the change in amplifiers and amplifier technologies. Those new amps and technologies provided reasons why I felt it wasn’t necessary to reduce the listed power rating. Specifically, the new amplifiers could deliver higher SPL than the previous amplifiers. Unfortunately, very unfortunately, many people have been conditioned to believe that Watts are the most important number to check on a spec sheet, so changing the number of Watts to a lower number of RMS Watts would have caused more confusion and generated more questions than leaving the numbers essentially where they were and removing the RMS notation. 

The questions would have been something like, “How can you make more SPL with less power?” and the answer would be, “You can’t.” So Watt’s wrong with that situation? Well, what’s wrong is the focus on test-bench, amplifier-maker, marketing Watts instead of how the amplifier design delivers useful power to a dynamic load to produce SPL, not to mention how the loudspeaker itself converts those (absolutely silent) Watts into pressure waves you can hear and feel. The obvious conclusion I came to is that the numbers provided under the Power specifications are comparable because they produce essentially comparable sound pressure levels regardless of how many Watts were measured putting power into a resistor on a test-bench. In other words, the power produced by the new amplifiers is better suited to producing SPL from dynamic transducers (aka woofers) than the previous amplifiers, regardless of how that power is/was specified. 

Back in the early days of SMPS amplifiers, they were amazingly loud and clear but they had no ass. They sucked on subs. It was a fact. Everybody knew, if you want fat low end, you need a heavy amp with a big power supply. You needed those old-fashioned RMS Watts and not those new-fangled Peak watts those SMPS amps were shouting about. And for what seemed like a very long time, that was true. But things change. A few people designing SMPS amplifiers were figuring out how to make them deliver bass. It turned out that SMPS actually had some advantages when it came to controlling big woofers and delivering big bass, but it took a few generations of designs to discover and realize that potential. 

SMPS amps still had a reputation for not being good on subs when I was involved in some interesting events. As I recall there were two in Oklahoma, two in Texas, one in Florida, one in Washington and at least two in New York in which I participated. At each event, several of the biggest, baddest bass amps on the market were brought together with several of the biggest, baddest subwoofers on the market and a variety of tests were done. Without getting too deep into the specifics, we (the subwoofer-obsessed community) were trying to figure out the best way to make the best possible bottom end. The biggest class A/B amps from Crest, Crown, QSC and the like were tested and compared to SMPS amps from Powersoft, Full Fat, MC2, SpeakerPower and others.

On various occasions, all amps were tested on a variety of subwoofer cabinet designs from an assortment of manufacturers including Danley, McCauley, EAW, EM, JTR and BASSBOSS. It was great experience and I learned a lot from these tests. For example, I learned that certain types of amps make certain types of speakers sound decidedly different and that their power rating wasn’t the determining factor. In other words, it was possible to pick a favorite amp for each subwoofer type, but it wasn’t possible to pick one best amp for all of the different types of subwoofers. For example, an amp that sounded best on horn loaded subs didn’t necessarily work as well on a vented sub, and vise-versa. 

There were tests of a variety of subs on the same amp. There were tests of a variety of subs on a variety of amps. At one big event, the group voted for a single subwoofer set with which to do a blind test of the available amplifiers. During the listening tests, the listeners made notes about what they liked or didn’t like about each amplifier without knowing which amplifier was connected to the subs. The amps were hooked up in random order, out of sight of the listeners, and they made notes on the amps from 1-7. The tests were done in this way to weed out bias and to separate the specs from the listening/feeling experience. Discussion ensued. There was no consensus on the winner but there was on the loser. Nevertheless, there were 3 top contenders in the amp tests, and for different reasons based on the taste preference of the “judges”. The SMPS amps did extremely well. Better than most had expected. The top 4 were all SMPS amps. 

As I recall, the three top amps were MC2, SpeakerPower and Powersoft. MC2 was judged to be the smoothest and was given the most points for “sound quality”. (I believe that’s partly due to their excellent, super-smooth limiter configurations.) Powersoft was the loudest, hardest hitting and was preferred by those who love big impact. (This was likely due to the extremely high voltage-swings that they are capable of.) SpeakerPower got the nod for “deepest”. (Words like “warmer” or “thicker” were used. An interesting difference between it and the Powersoft.) These were SUBJECTIVE tests, the conclusions were based on opinions. Most people there were surprised by which amps they ended up preferring. In other words, once they heard the amps without knowing what they were listening to, and they committed their experience to writing, when they learned which amp they preferred, it was very often not the one they had thought they preferred before the test. Another thing they learned was that neither the weight nor the Watt ratings could predict the winners. 

What would you do with the information learned from tests like these? Well, MC2 didn’t make power modules for self-powered speakers. The other two winners did make modules, but they were good at different things. Impact, which is produced with high-voltage swings over short duration, is desirable for mid-bass, midrange and HF frequencies. Subwoofers, in my opinion, are not the tools with which to produce impact, which requires rapid acceleration of transducers to create rapid rises in pressure. Subwoofer cones are too heavy for that, at least if they are actually subwoofers and not just extra woofers, so the best amp for a subwoofer would seem to be one that doesn’t necessarily deliver a lot of output very quickly, but rather one that can sustain its output for a longer duration, or so it seemed from the comparisons at the time.

Now you’d expect amplifier manufacturers know their products’ strengths pretty well, and they would also tend to know, but not disclose, their weaknesses. But I chose different amp manufacturers for different applications based on their specific strengths. 

SpeakerPower made amplifiers that could deliver current like no other amplifier I have ever tested. If you hooked up enough fans to one of the biggest ones, you might be able to tig-weld with it. There was no subwoofer load it couldn’t drive. A proper diesel of an amp. They had no trouble putting out their 2400/4000 Watts into 4/2 ohms respectively. SpeakerPower promoted the amps based on those specifications and we put them to good use to do what they did. That’s the good news.

Big Watts was, and is, Powersoft’s claim to fame. Powersoft could deliver massive voltage swings for huge dynamic impact. The Powersoft amps did what they do best, which made the mid-high cabinets sound loud and powerful. More good news!

So what’s the bad news? 

The bad news is that although the SpeakerPower can deliver massive amounts of current, and can drive large numbers of woofers on a channel, they can’t deliver the higher voltages that are needed to deliver increased SPL from just 1 or 2 woofers to make them competitive with more recently developed technologies/topologies. 

The bad news is the Powersoft’s voltage swings were impressive but brief, which is why they specify using EIAJ, and while they were the high-voltage leaders  when we first started using them, competitors are now offering even higher voltage swings in more practical configurations that deliver superior performance.

Is there more bad news? Each company’s specifications were based on a different set of tests, a different standard for achieving the stated power and a different USP/secret sauce. 

The SpeakerPower amp will deliver 2400W by using 98 Volts to push 24.5 Amps through 4 Ohms and it will do that for 10 seconds before the output devices start  even thinking about waving flags and declaring a heatwave. Impressive! But a 4-ohm coil can’t often take 24A for 10 seconds without suffering heatstroke. And, importantly, very importantly, most of the impedance curve of a loudspeaker is above the driver’s nominal impedance. So even if you can deliver enough current to melt any reasonably efficient voice coil at 4 Ohms, what happens when the impedance rises? How much power do you get to use at 20 Ohms?  Only 480 Watts. How do you add 3dB to the output of a loudspeaker? Double the power. OK, only 960Watts. Well below the amp’s stated capabilities, but no way to get there because the only way to raise the power is to raise the voltage. To get 960 Watts through 20 Ohms you need 138 Volts. If you can’t deliver those 138Volts, you won’t get those 3dB. What should you do? Stick with the amp that can deliver what it says, a full 2400Watts through 4 ohms from 98 Volts, or would it be worth looking for an amp that could deliver more voltage because you can actually use that higher voltage to generate higher SPL? 

And what about on the other side? The much touted 3000 Watts of Powersoft Power? How does Powersoft achieve this remarkable amount of power? They test differently. They called their power Watts RMS EIAJ. That reference is hard to find now because they caught a fair bit of flak for it, so it’s disappeared from most of their specs, but here’s how it works. Meeting the EIAJ standard requires the stated power to be delivered in a repeating cycle for 8ms out of every 32ms. This represents a fairly dense 25% duty cycle compared to the average duty cycle of full-range music at 12.5%, but critically it allows time for the power supply to re-charge between bursts. In other words, the bridged amp is supposed to deliver 3000 Watts RMS for 8ms. The test signal is 1kHz sine wave. 8ms allows 8 diaphragm cycles at 1kHz. It would be loud, for sure. But not deep. Where does that leave the power for bass? 8ms would allow for one diaphragm cycle at 125Hz.  What if you don’t allow the recovery time? To put that another way, what happens to the power output when the demand is sustained for longer periods? Like actual bass notes? It drops. A lot. As I recall, and I’ll have to re-verify to be sure, if you run a continuous bass sine wave into a Powersoft 3000W amp, sustained output drops to about 42V into 4 ohms, or about 440W. Not the ideal result in a subwoofer.

So let’s compare. Worst-case scenario: Powersoft’s 440 Watts into 4 ohms, not great.  SpeakerPower’s 480 Watts into 20 Ohms, also not great.  

Best-case scenario: Powersoft’s 1200 Watts into 20 Ohms, which should be pretty loud, but it will be brief.  SpeakerPower’s 2400 Watts into 4 Ohms, in which case the amp will survive but the speaker will need protection. 

Protection? What does that mean? It means limiting. Limiters have to be in place to protect the voice coils from overheating due to passing too much current, and to protect the driver suspension from excessive excursion. Interesting? Yup, you can’t actually use all the power that either of these two amps provide. One of them will melt the coil into a puddle and the other will smash it into a pole. Unless they are limited. But it’s never that simple because either one could smash the coil or melt the coil, so they both have to be limited in both aspects. And if they’re limited, how many Watts are you getting from your 2400 or 3000 Watt amplifier after all? Well, this is getting closer to the point. How many Watts are you buying? All of them? Without the limiters in place, there’s no warranty on the drivers… 

Are you buying Watts when you buy a speaker? Technically you’re only buying Watts when you pay your electric bill. In the big picture, when you buy speakers, what you’re probably after is happy customers, and a happy you, because you made them happy and maybe because it was easy and trouble-free to make them happy using the speakers you bought. Maybe a happy you because you got to play music and it sounded great!  If you checked the electric meter and it turned out you used less watts than you expected, would that make you less happy? 

But seriously, did I say not all the Watts? Here are some thoughts: If there are limiters that restrict the output power of the amplifier to protect the woofer or tweeter, should the published power rating of the amplifier be reduced? And should price of the cabinet be lower because less than the absolute maximum number of Watts of which the amplifier is capable can be accessed at any given time and at any given frequency? Or for a shorter duration of time than forever? If you bought a 3000 Watt speaker and a year later you learned that it turns out you haven’t been using all 3000 Watts, should you get a refund for the Watts you haven’t needed? If the speaker can do the same jobs and play at the same sound level and make the same money while being more efficient, using less power, wasting less Watts as heat, is the speaker less valuable? 

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Side note: Did you know that horsepower can be converted into Watts? Mathematically, that is. I bought a motorcycle that can deliver 160 horsepower. That’s 117,679 Watts! Damn! If only it was an amplifier! Nobody usually bothers to clarify but yes, that’s peak horsepower, with the peak output only available at 9200RPM. It turns out I can’t use all 160 horsepower for a lot of reasons… Firstly because that 160 horsepower is measured at the crankshaft output. It turns out that at the rear wheel there’s only about 135 horsepower available. And it’s only available at 9,200RPM! What a rip-off! Of course the thing is a beast if you wind it up to 9200RPM. Proper! But I don’t need to, meaning I don’t use all 135 horsepower, never mind 160 horsepower. But if I did wind it up to peak power RPM and try to use it all, I couldn’t anyway because, well, traction control, and, traffic, and, laws, and, corners, and, tires, and, well, I know better than to expect to use all the horsepower because shit will go sideways, which is another fun topic altogether…

Nevertheless, I don’t want a refund because it’s nice to know they put all the parts in there that have the POTENTIAL to deliver that peak horsepower, because it’s effortless for the engine to produce 100 horsepower, and there are occasions when I think I might have used that much… maybe. And there have been occasions when, at nowhere near peak horsepower, I’ve noticed the traction control kicking in, cutting power, and that’s not a bad thing when you’re crossing some gravel in an intersection, keeping things under control… Probably better than the alternative! So there again, I don’t mind not having access to all the peak horsepower because it could very well do a lot more harm than good. I have to admit, the folks who built the motorcycle put too much power in it, so they put limiters on it, because nobody needs motorcycle with 160 peak horsepower, but people like me buy them because they are fun to play with and sometimes fun to brag about.

I’ll admit I don’t tell people I have a 135 horsepower motorcycle, I tell them I have a 160 horsepower motorcycle! Of course I won’t have 160 horsepower at the rear wheel, and of course I won’t have 160 horsepower at any other RPM, and I’m not all upset about it. Because I didn’t buy the motorcycle because it had a power rating of 160 horsepower. I bought it to ride. When I ride, I have all the power I need, and I’m also happy that I don’t need to ask it to operate at its limits. I don’t care if I can’t actually use all the horsepower they claim it’s capable of producing. It does what I bought it to do. No complaints.