This is good news, just wish 'more affordable' was even 'more affordable' but those nasty laws of physics I'm sure interfere.
Probably no way to "reasonably" reduce cost of say the Plantarium Alpha monitors (F3 = 70 Hz). That approach makes so much sense to me, but the price (¢4,000/pair) gives my great pause.
Can't say I blame you a bit for wishing for "even more affordable", and if it turns out that my costs are a bit less than anticipated, that will show up in the pricing.
Each speaker enclosure houses two independent two-way speaker systems, each optimized for its particular job. The enclosure itself is quite labor-intensive; the labor cost will probably be 2-3 times higher than is normal for my floorstanders. And I really don't like to skimp on dynamic capability for my drivers because I think that's an important area that most home audio speakers fall short on.
On the dynamics thing: I like for the peaks to be uncompressed. My general rule of thumb for achieving this is, I want the drivers to be able hit those peaks at 1/10th their rated power handling. And that would be based on their RMS (or more likely AES) power handling, not "music program" (which is twice as high), and not "peak" (which can be inflated enormously by using a shorter and shorter duration peak). My focus is not so much on keeping the voice coils from melting; rather, it's on keeping them from getting hot in the first place.
High efficiency and/or large diameter (or multiple) voice coils in each frequency range will get us there, but they may present other challenges along the way.
Anyway following these guidelines, if we want 90 dB average SPL and uncompressed peaks 20 dB higher, we need a system that can deliver 110 dB at 1/10th its RMS rated power handling. Well in this system I fell short a little bit. The AES power handling of the system is 400 watts, and the claimed efficiency is 92 dB, for a calculated 108 dB at 1/10th power (40 watts). That's still pretty good.
And, there is a hidden cost savings from the higher-than-average efficiency: Reduced amplifier power requirement.
To hit that same 108 dB peak, a "typical" 87 dB efficient speaker would need about 150 watts. And this is before we factor in thermal compression - it that system's RMS power handling is 150 watts RMS (or 300 watts "music program"), well we might actually need something more like 250 watts to deliver a 108 dB peak.
Depending on how expensive your taste in amplification is, being able to do well with 1/3 to 1/5 the amplifier power might make a significant difference.
A rule of thumb among the SET guys is, shoot for an amp/speaker combination that would theoretically give you 102 dB, and adjust from there for your room size and listening style. This system would hit 102 dB with 10 watts, so that would probably be a decent ballpark starting point for tube amps (for solid state I'd like another 3 dB headroom before clipping sets in, so more like 20 watts).
So back to the specifics here, and a look at how my "claimed" efficiency is derived. Each box will have four 6" midwoofers in it, partially so that we can run 'em in series-parallel and end up with an 8-ohm load. Each is 89 dB efficient based on its T/S parameters - which is a conservative yardstick (the manufacturer's spec sheet says 91 dB, and eyeballing the curve that's not based on a midrange peak). Four 89 dB midwoofers would theoretically give us 95 dB efficiency, but again I take a conservative path because half of the midwoofers are dedicated to the reverberant field. If I were making my efficiency claim based on an optimistic yardstick, I could easily claim into the upper 90's. If I also added several dB in anticipation of the reverberant sound's contribution at the listening position, might even claim 100 dB. This isn't so far-fetched: An amplifier manufacturer once compared one of my 93 dB speakers with a "101 dB" speaker by someone else, and said that they sounded as if they were the same efficiency. (Ever run into a situation where, on paper, the speaker/amp combination should play plenty loud, yet it's falling well short? Optimistic yardsticks. I'd rather lose those sales than have someone be disappointed with something they bought from me.)
My point being, there's decent value for my asking price.
Sorry for the long-winded tangent, dynamic capability is not the raison d'etre of this system; rather, getting the reverberant field right is. But the dynamics will be there too, which isn't always the case.
