This is a new remastering/pressing at 45 rpm. Would love to get my hands on an original to compare. Listened again and does sound marvellous.
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Has Class A/B amplification in subwoofers become rare? I think even REL makes a sub with Class D, correct?
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Not sure if it’s rare, but it seems less common than before. Yes, REL does use Class D plate amps (not sure if that applies to all models). As far as I recall, Rythmik still uses Class A/B plate amps on their upper tier subs.
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Class D are naturals for subs compared to AB. D’s are small, light, powerful and run cool. SQ in bass is not an issue.
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To my ears bass notes in quality vs non quality amps are in fact a reality!
I believe that only the 370 watt rythmik amps are class-AB. This looks like the old Vistar Audio or Keiga plate amps that were around for many years.
There are still some BASH amps being used (class A/B output stage but with tracking power supply). The best Class D nowadays have incredibly low output impedance, so low that it is dominated by the cable and they can have awesome bass performance. Having 95% efficiency of a Class D amps makes a humongous difference to the amount of power you can realistically deliver into a woofer and how much heat and heatsinking needed.
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Hey Mark:
Thanks for correcting me.
I agree with you. Perhaps I should have been more specific. Subs typically operate at the lowest frequencies. The crossover generally filters out mid base, where distortion is more discernable and audible. I could be wrong, but I seem to remember that subwoofers can have THD of 10% or more.
I must say I am somewhat disappointed by the physical design of the PS Audio Foundry F12.
14.75"W × 16.75"H × 17.5"D
It appears to be another big, fat, nondescript cube (nearly), just like 95% of all the other subwoofers in the world.
After seeing the innovative design and appearance of the FR series loudspeakers, I expected more and better. Couldn’t you take the bottom half of the FR20 or the bottom two-thirds of the FR30 and create a lovely, sleek sub with an elegant rounded bottom? A sub looking like that would be really cool (and different)!
This would certainly harmonize better visually (and physically) with your full-range loudspeakers.
Oh well. Another opportunity missed.
Welcome to the forum.
I wouldn’t know for sure, but my guess is there is a reason why all stand alone subs are boxy cubes. Something to do with acoustics and resonance. Have you seen a a substantial 12” sub that is not a cube?
I’d be interested to hear Chris’ answer.
A quick search on sub woofer design shows this:
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You probably should take back your “welcome”. Talk about someone going out of their way to not get along as their first post. But you are much nicer than I am, lol
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Very few.
I suspect you are correct.
I guess that, in addition to acoustics and resonance, a cube is the easiest way to achieve a required internal volume.
Maybe it is just aesthetics, but I do find a taller, narrower, deeper sub to “appear” very elegant and less boxy and “clumsy.”
(Much like the appearance of the FR series loudspeakers.)
We struggled with this quite a while and decided to go with the box approach because of the importance of stacking. Stacking subs is a pretty big deal and, unfortunately, the bottom half of the FR series rounded look wouldn’t take too well to a 3 or four stack.
Where we certainly did not compromise is in performance. Not even by a little and here is where Chris is setting new standards for others to follow.
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One certainly cannot argue with the performance.
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I didn’t mean it to sound aggressive. I’ll take that feedback and try to be more thoughtful in future responses.
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@Gene_Hood My apologies for my response. I could have said it differently but I got more involved with making a point that considering your point of aesthetics, which is a very good point.
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You were ok, possibly too polite 
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We appreciate the feedback - it’s a fair comment. Like so many product design decisions, there are a lot of factors involved. They may not align with your sensibilities, but let me walk through our thinking.
If you look at the market, why are 95% of subs rectangular prisms? Why isn’t there more innovation here? The answer is that bass wavelengths are so long that enclosure shape (beyond internal air volume) doesn’t meaningfully affect performance. A curved enclosure would do two things: increase cost and reduce performance slightly by limiting internal volume. In a competitive market, does a unique shape that serves no functional purpose—paired with somewhat worse performance and a higher price—actually help the customer or increase sales? We didn’t think so.
Our goal was to create something priced sensibly alongside our smaller speakers while delivering enough performance that one or two units would be an uncompromised solution even with our larger speakers.
I actually worked at a company in my twenties where we licensed a Cary Christie design: a force-cancelling dual 10" sub with a hot-pressed MDF cylinder coupling the drivers together. That shape served a real function. But relatively few people bought them. There’s a persistent mental block around side-firing subs, with customers assuming placement near a wall will hurt performance. (It doesn’t.) KEF and others continue with similar approaches, now with better industrial design and somewhat improved market acceptance.
Generally, subs aren’t “look at me” products—they’re “hide it away” products. The best placement is often in or near a corner, tucked against a boundary. There are designer micro-subs and exotic-looking options made purely for aesthetics: REL does nice work with wood grilles and cosmetic touches, and Bowers & Wilkins made the PV1, but performance per dollar and absolute performance tend to suffer.
We made a mid-sized subwoofer. The dimensions you cited include the feet, grille, and heatsink fins, so the actual enclosure is more compact than it might appear—just under 1.5 cubic feet internally. That’s certainly larger than some, but far smaller than others. Go much smaller and the air spring raises the woofer’s resonance, demanding significantly more amplifier power. When you’re displacing large amounts of air—our woofer moves 60mm peak to peak—the air itself becomes nonlinear, increasing distortion, and the higher current required introduces additional nonlinearities in the driver. High-output, ultra-low-distortion bass will always perform better in a reasonably sized enclosure; micro-subs simply aren’t the best solution for a serious music system.
As Paul mentioned, we originally considered a more exaggerated curve on the front panel, but it didn’t look right when units were stacked. We actually built a prototype of an early more curved design.
One thing I consider with every product is how it functions outside the PS Audio ecosystem. Does this sub look good and work well with other brands of speakers, or in a home theater? I’d love to build a subwoofer line within PS Audio that earns broader market adoption for anyone looking for a high-performance, music-first subwoofer.
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Thanks, Chris (and Paul). Our primary speakers are front and center where they must be for sound reproduction. In order for a sub to do its job of room correction (not just adding more base), it shouldn’t be with the main speakers. So we prominently see our primary speakers whereas the sub is almost hiding somewhere else. Glad you put the money in sound and features, not looks that I would rarely see.
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No offense taken. All good.
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