Apart from making small tweaks to the components in the analogue active crossover, which will make only small changes to the sound, the NS-1000M are about as good as I will get them from the stock crossover points.
I have been experimenting with other speakers, but I keep coming back to the Yamaha's and their exceptional mid range clarity and imaging.
They are not without their faults, as I have mentioned before, the bass falls off early, with an F3 above 50Hz. It's all about that fabulous 3 1/2” Beryllium Mid Dome, it certainly dominates the voicing. It has a high upper crossover point of 6kHz and with the shallow roll off from the simple passive second order circuit it will still be contributing at 10kHz and beyond. The tweeter has a bit of a ragged response at its lower end and drops off quickly at the top (15kHz). The dominance of the mid dome can be verified by switching the tweeter off. I can do this easily on my active system with the flick of a switch. It really doesn't contribute much, other than a sparkle to symbols etc. Having said all that, I keep coming back for more, so there is something fundamentally right about the sound.
I've been asking myself the question, as to what would happen if the tweeter crossover point was lowered and/or a steeper slope was introduced. This and maybe replacing the tweeter with a modern ribbon tweeter, I have been very impressed with the Fountek NeoX 1.0 I've been working with. Then there is the bass, keep it as a sealed box, but use a driver that goes a bit deeper?
There are lots of variables, I certainly wouldn't want to loose the signature sound, but maybe loosing some of the steely sharpness at the top might be a good thing. This might make them more Amp friendly, as they do need a bit of care when matching?
They obviously would no longer be an NS-1000M, but maybe a modern take on the theme? This is an image of the kind of thing I have at the back of my mind. “NS-1000 Revisited”
It would need a lot of experimenting with crossover points and slopes, so a minidsp would be used to help achieve this. I have had concerns in the past about using a DSP with my Turntable, but after hearing a very good TT recently, through just such a set up, I am less worried, as the results were excellent. I would love to at least try this and see what can be done, we all aim for that audio Nirvana, I think mine is based somewhere around the NS-1000M Mid Dome.