What exactly is their DSP doing? Is it an active cross-over that would allow you to activate Axiom speakers?
If not, I would not expect dramatic improvement indeed. If you want one consider activating your speakers, including PMCs.
Sasha: These are really good questions. In fact, it took me a couple of days of talking to Axiom to understand it. It was not their fault, but mine because I'm almost completely clueless when it comes to the technical part of this hobby.
Anyway, this is how I understand it, in terms of my own system:
I will be receiving an analog signal into my Harman Kardon 3490 receiver, usually from the analog out of my BDA-1 DAC. The DSP will be looped to my HK; that is, I will connect the pre-out of the HK to the input of the DSP. Then the DSP, which has two converters, will convert the analog signal to digital, then process that digital signal, then with its second converter, convert the digital to an analog signal. The DSP's processed signal goes back to the HK's main amp in connections and out to the speakers via the connections I already have. I was concerned that this might in effect negate the benefit of using my BDA given that all DACs are different. However, Axiom before doing anything else has tested the AD and DA elements of the DSP, and has assured itself that these to not change the analog signal at all.
But it is the processing part of the DSP that, in fact, does change the analog signal going out. The code, which is written to be speaker specific, is crafted to produce a flatter response than can be achieved by the speakers' passive crossover units. So, for example, the frequency response graph will show variances of + or - 1.5 dB rather than the present 3 dB. But Axiom isn't creating code based on a single graph reading, but rather a number of them, taking into consideration room effects, etc, to create its listening window graph.
I'm sure you're absolutely right about being able to do this via an active model of the PMC speakers. However, this, for me would be going in the wrong direction.
First, this is about a second system, meant originally to be a low cost one in the neighbourhood of $1000. The new HK and the M80 turned that notion into a cocked hat, and now it is a modestly priced system. The DSP will take the total cost even higher. But an active version of my MB2i speakers from PMC, or somehow retrofitted, if that can be done to accept a passive crossover, would be many thousands of dollars. I am, to be sure, nutty when it comes to audio, but not that crazy. Here's a car analogy strictly in terms of price, not performance: I started out to limit myself to a stripped down model of a Ford Focus. I now am into a well-equipped Toyota Camry. Going passive with my MB2is would take me into the Porsche range. And doing that would make no improvement to my second system.
Second, while I don't argue with the merits of active crossovers, I am one of those who really doesn't want the added complexity of an active crossover system. If you're following the topic of James Tanner's new speaker being built with Axiom, I believe he's said somewhere that he's hoping to get the benefits of active passovers without their complexity in terms of ease for users.
So I see the DSP as an improvement in the performance of the M80s at a higher, but not draconian, investment. And there's no doubt about it that buying the DSP is a bet that the cost is worth the noticeable, but not dramatic, improvement. But this would not be the first time I've done that. In fact, buying stuff, not just audio gear, usually is that kind of bet.
And I"ll refer you back to my review. I bought the M80s to get a noticeable, but not necessarily dramtic, improvement. Turns out I got a lot more. I've had that happen to me with several pieces of equipment in recent years: BDA-1, BDP-1, Torus C15, 7BSST2. I'm hoping my string of good luck holds with the DSP. And if it runs out, Axiom has a 30 day return option, which I feel I'm unlikely to use.
BTW, in deciding to pre-order the DSP is something of a testament to Axiom. The number of audio companies in 40 years to have instilled enough confidence in me to have pre-ordered a yet-to-be built product can be counted on a single digit: Bryston.
Dave