[sandston]

So here are some measurements I took before and after the crossover change. These were taken using REW at 1 foot from the speaker and three feet from the speaker in plane with the coaxial driver setup. The measurements shown are gated in order to cancel out room reflections. While this is probably far from perfect and I am no expert in this I wanted to have a baseline so I could tell what was occurring. The drop in the bass driver is evident in the measurements and the tweeter seems to be performing nearly identical to how it was performing before the mods. The interesting thing to me is the Phase changes. I know less than nothing about what this represents and would love to hear some analysis from the community. On the surface it looks cleaner than the original phase plot but based on how I measured it may be meaningless. I plan to do some research into the subject. The plots are pretty well labeled but if you have any questions id love to dialogue a bit about the results with anyone who cares to comment. The images in order are 12" measurement original xover, 12" measurement new xover, 12" measurements compared. Followed by 36" original. 36" new, 36" compared.

[ric]

Please see my posts from this topic here at AC: https://www.audiocircle.com/index.php?topic=150989.0

Ten dB sounds like a lot, but I'm the wrong person to comment other than hopefully it's the break in aspect of it rather than a problem with the new crossover.

My girlfriend also could care less about sound quality. Usually, her reply is "I thought you got it to where it was great why do you need to do more?" To which I reply, "because it will sound better".
 
I would say overall, for me, the biggest change in the crossover upgrade is texture/palpability. Hearing what I guess they would call low level information, let's say for classical plucked strings, violin, cello notes have a fullness that previously was flatter sounding. Of course if you hear plucked strings better, plucked electric guitar notes also carry more weight, as do vocals--pretty much everything sounds more fleshed out and fuller. With the path audio installed, the presence factor, again using orchestral strings as an example, fill the room vertically as they do at a concert, with more air. All of these improvements for me are money well spent. There is the danger that as a system becomes more sensitive one can hear more of the bad recordings or nuances that would be a negative, but overall I would say that recordings that previously sounded good, sound very good, and that recordings that sound great, sound fantastic. Hope this helps!

[sandston]

I had a long satisfying listening session last night with the new crossovers. I would highly recommend upgrading at least some of the parts of the crossover in the TM. If I was to do it in stages I would start with the two resistor in the signal path of the tweeter, replacing them with Path Audio Resistors from HIFI collective. The value of these are 30ohm and 3 ohm. I would also replace the 1.5uf cap in the tweeter section with a high grade copper foil capacitor. I went with the Jupiter over the Miflex as it was on sale at Sonicraft. In the woofer section one should consider replacing the inductor. I went with Claytons recommendation and used the Jantzen C-Coil. This is 3.5mH. This tightened up the bass and got rid of some of the lower octave boominess. This should cost you around $200 per speaker and is well worth it my op pinion.

Do these speakers need mods? Absolutely not. Is there room for improvement? I would say yes. Keep in mind that if these mods were a factory option these speakers would cost $1000 more at retail.

I have been experimenting with one other mod for the speakers. Like several other M3TM owners here have mentioned I find the speakers, at times, lack a bit of high end sparkle and extension. For modern recordings and long listening sessions these speakers sit in the sweet spot but at times on my system (All Tube) they can feel a bit over relaxed. I have been playing with bypassing the resistors in the tweeter section of the crossover. This is easy enough to do with a set of insulated alligator clips and a short piece of insulated wire. Bypassing the 30ohm resistor in the parallel notch filter results in a large jump in high end volume and energy but the overall balance is thrown off and the highs become fatiguing quickly. I did notice an increase in detail and sound stage expansion which I attributed to the bypassing of the resistor. Its an interesting experiment to try. Bypassing the 3 ohm resistor yielded a much more subtle result but gives the high end a nice punch and sparkle. While I don't enjoy the result on all music I find its quite nice on live recordings helping to give more of that sense of being there. I like this mod so much I am putting ordered a switch to bypass this resistor. I picked up two switches from TE Connectivity for something like $7 each. They have a silver plated copper contact and gold plated solder lugs which should provide more clarity than the alligator clips!