In today's post, Ian Colquhoun and Andrew Welker explain the evolution of the newest Axiom speaker, the M100 floorstanding speaker, recently released from beta.
Ian Colquhoun: The M100 is quite large and contains three 6.5-inch high powered drivers. The whole goal behind this product came from the return to stereo out there. We're finding with a lot of our customers are looking for very high-powered, natural-sounding stereo pairs of speakers with large soundstages.
The M100 has been in development for four or five years now. Over that period of time, Andrew has developed a new woofer and a new tweeter, which were both a part of this project. We've found that people are returning to two-channel systems and sometimes using just two speakers in a very large space. We wanted to make sure that people could play these loudspeakers loud and clean, use big amplification, and have no compression happening in the bass whatsoever.
Andrew Welker: We started with what was then our flagship the M80, which has been around since the mid 90s. That's not a speaker we ever looked at as having any sort of limitation. It has good frequency response, good extension, sounds great, can play loud . . . there really weren't any major identifiable issues. But in most applications, our customers were using M80s in the context of a home theater system with a subwoofer.
When you take a subwoofer out of the equation, now extension and linear extension, particularly at very low frequencies, becomes something that you are looking for. You need to have good dynamic capability at those low frequencies to really give you the sense that you've got full bottom-end, full frequency range, and you're not losing anything - especially at high levels.
So we took our existing drive units and said
"What do we need to do to get this dynamic capability and this extension right to the very bottom end of the usable frequency response?"
There were two major things we needed to address. The first one was the newly redesigned woofer, which is available in high-powered versions for the M60 and M80 as well. It's a woofer with a larger voice coil. It's got a larger roll surround, which means there is more linear excursion capability, and it can handle far more amplifier power than the existing M80 can.
Now that's not to say the M80 is any slouch! But if you're going to be running high levels right down to 30Hz or 25Hz, you need that power handling capability.
The other thing that we've got to remember is that if you're only going to have two loudspeakers carrying the full range, if you've got really high dynamics, you're not splitting that output level between five or seven speakers and a subwoofer anymore - you have to get that out of two speakers. So in large spaces you have to run more power through the speakers to get that satisfying dynamic level up. 
In the tweeter to deal with power handling, we've gone to a die-cast faceplate assembly. The old one was plastic. That's actually significantly increased the power handling capability of the tweeter due to the cooling: we're actually using the faceplate as a heat synch.
The other thing to remember is that in very large systems, you naturally get a very large soundstage. You're surrounded with loudspeakers. In two-channel, you're depending very much on those two speakers and the quality of the recording that you're listening to.
One of the things we started really paying attention to a number of years ago was something called the listening window and the sound power. And really these things just talk about what we call the family of curves, which is how the speaker behaves from a frequency response standpoint if you measure all the way around the cabinet - so at any point. 
Look at this graph. It shows the purple curve on top is the listening curve of the M100, and the green curve on the bottom is the sound power. Now the listening window is simply average that takes into account +/- 45 degrees from the on-axis frequency response of the speaker, and creates an average. That gives you an indication of what your perceived tonal balance of the speaker is going to be in a room. You don't any major discontinuities: you want it to be nice and smooth.
Similarly, the sound power takes into account the entire reflected energy that's going to be in the room, combined with that listening window signal. Again, you want it to be smooth with no discontinuities. That's very nice from a technical standpoint, but what does it mean in terms of of the performance of the speaker?
What it really means is the better the listening window and the sound power can be in terms of smoothness, you get a wider, more enveloping sound stage, you get better imaging, and really now you have two speakers that not only seem to disappear into the recording, but they actually fill the space. That's really important in a two channel set-up.
So there's a few of the things that we endeavored to do with the M100. We've started to trickle down the developments into the other models, but the M100 is really an ultimate statement of a true full-range speaker that is perfectly suited to two-channel reproduction.
Ian Colquhoun: Just in closing, we now have a complete line of these high-powered tower loudspeakers which are designed specifically for stereo reproduction: M60, M80 and of course the M100.
The M100 is a perfect match for the ADA 1500 amplifier, which in a two-channel configuration into the 4-ohm load of the M100, can deliver 750 watts per channel. This is a speaker that loves that kind of power, and the package gives you the ultimate two-channel system.
