[Bo Dacious]

Has anyone done a crossover upgrade on classic Mirage tower speakers (M-3si, M-1si, etc.)?
I have the M-3si's.  Great speakers, over 25 years or there abouts, never felt the need to trade them in for anything else.  But looking at them recently, there is definitely scope to improve the crossovers and internal wiring.  I also have a copy of the crossover schematic.
If you have, I would love to hear your experience.  Thanks.

[Hobbsmeerkat]

We've had customers ask Danny about Mirage speakers, but we've not yet worked on any.
Looking at the Stereophile measurements, there's plenty of room for improvement.
Rebuilding the crossover with better quality will go a long way to improving clarity and soundstage performance.

[Bo Dacious]

Interesting.  Soundstage is one area where these speakers excel, particularly off-axis.
The original Stereophile review was quite complimentary and over all the years I have been quite pleased with them.  They are paired with a pair of the Mirage BPSS-210 subwoofers and the LFX-3 subwoofer crossover.
But by now after nearly 30 years (amazed that its been so long), since these speaker get near constant use 15 hours a day 6 days a week, something is going to give -- like those crossovers.  I agree, especially after looking at them (photo follows), the crossovers have considerable scope for improvement and plan to do it.  There just isn't a lot of space on the board for better -- larger -- caps and inductors.  How we accommodate them we be a key part of the solution.

[Danny Richie]

Agh!

[Bo Dacious]

LOL!

Here is the schematic


Not a lot of space in the cabinet either. I'm figuring on separating out the bass side and mounting it on the other side of the speaker, and hopefully there would be enough space for the expected larger components (caps, etc) for the mid and tweeter side of the crossover.

[Danny Richie]

Don't count on reusing the circuit board. Any higher quality parts will be much larger and will never fit on that board. I would recommend point to point wiring a new crossover.

[Bo Dacious]

I agree.
The old board won't work at all.  Where the old board is mounted in the cabinet, there isn't that much room for a bigger board either -- maybe a half inch on the short side and maybe a couple of inches on the long side.  Mounting the bass circuit, which appears to be separate from the mid/tweeter circuit, on a separate board, would probably make enough room for the upgraded mid/tweeter components in the existing location.

[Bo Dacious]

Location of the crossover board, accessible only through the opening for the woofer (unless we take apart the cabinet, which would be a real project).

[Bo Dacious]

One question I have about potentially upgrading the crossover is one of the inductors in the tweeter circuit.
With the idea that you do not want any ferrite core inductors in the tweeter circuit, how would you upgrade this particular inductor, if at all.
It is in series with the tweeter, but it is exceptionally small, only 0.011uH  (11nH).  From the speaker parts sellers that I know of, there are no inductors anywhere near that small in value. (Did find air core inductors that small, 10nH, on digikey.com, but really unsure of their suitability/quality for audio or whether any differences in Rdc are critical or can be (or need to be) compensated for.  Here are the relevant details from the crossover schematic and photo posted earlier:




Thanks.  I appreciate your insight on this.