My major Minimus 7 Zilch mod mod v1

[plavatar]

I took an unfinished, 25-yr-old design from a stalled business and scaled it down for the Minimus 7.

It took me 2 weeks, from sitting down to get serious, to completion.

I Zilched the crossovers:



And came up with my own setup:



And it fits well in the enclosures:



The right and left enclosures are slightly different. The tweeter spheres are different sizes (it's a visual and auditory test).

I made 1 prototype to test, before building the final pair:



They're stuffed with polyfill, if you're wondering. And they're on risers to line up with my ears on the desk:



It's been a huge albatross in my life, not making the speakers I was meant to so many years ago. It's nice that I was able to adapt the Minimus build to my scaled-down design.

The stereo imaging, near-field, is amazing for a tiny desk setup (WiiM Mini, Douk A5, NeoHipo DC-10). I hooked it to the main amp/pre in the bug room, and they sounded great for their size!

I recorded everything I did. I might YouTube it.

Many thanks to everyone here who is behind the Zilch crossover mod. Great work!

 

[plavatar]

A 100% terrible room setup for the big stereo (it's temporary). I just wanted to use the tube pre and big ol' ChiFi amp on them.

YouTube might block the music, but, to show they're alive [edit]... Had to use Drive.

IMG_1100.MOV

drive.google.com

 

[StimpyWan]

A 100% terrible room setup for the big stereo (it's temporary). I just wanted to use the tube pre and big ol' ChiFi amp on them.

YouTube might block the music, but, to show they're alive [edit]... Had to use Drive.

IMG_1100.MOV

drive.google.com

Sounds great...! Very balanced and natural through my work stack (Schiit Lyr 2 tube head amp, Bifrost MB DAC, and HiFiMan HE400SE phones)...! Well done...!

 

[gizzyman47]

Nice job! I like it!

 

[Pete B]

I only skimmed this but where did you get the spheres or did you make them?

 

[plavatar]

I only skimmed this but where did you get the spheres or did you make them?

I made them.

Since my idea to start a local speaker company 25 years ago (that made ceramic enclosures) stalled, I've had speaker ideas on the shelf in my brain (and in my notebooks) waiting for me to figure out how to get them made. it's been a not-insignificant regret factory on my back.

Three years ago, I needed to learn 3-D printing to try and start an abstract and strategy board game business. Since the current political situation killed our manufacturing negotiations this year, I was looking for something to do to keep my mind off of it for a little bit. I decided to upgrade my long-neglected Minimus (thank you for all your work and contributions!), and was just about to start the standard upgrades when I thought 'Why don't I make a scaled-down version of the first speaker I wanted to build using the parts from the Minimus?'.

One of the biggest problems is making sure to get the internal volume correct, what with varying thicknesses of walls and determining a good width for the flat face. I'm not a math guy, and my friends who are math people were frustrated by it, so I ended up using ChatGPT and Claude AI to help me get my measurements. I'd already been using both of those products for our game business and personal projects. I'm surprised it took me that long to think 'Gee, I could revisit my speaker ideas…'.

So within a week, I had made the prototype to check the measurements and fit and finish. Then the second week I was able to print the pair of enclosures that I would transplant the Minimus parts into. Looking back on it, it went way way way way quicker than I imagined it would. I wish I had had access to 3-D printing and artificial intelligence 25 years ago.

I am incredibly pleased with the build. Not only does that crossover upgrade make a tremendous difference, but the layout in shape of the enclosures adds an audible improvement to imaging and soundstage.

I created the models in a low resolution application, so my next step is to redo it in a better program. However, the subtle diamond like lattice under the skin of the spheres is something that my oldest daughter loves. I wanted them to be completely smooth, since that was the original intent. However, I kind of get where she's coming from. It's a nice look, but I don't think it comes through in any of my images. Maybe?

 

[Pete B]

Great work! I have to say that it looks very professional.
May I ask what software you're using for the 3D design? I don't like the one that I've used in the past.

 

[plavatar]

Great work! I have to say that it looks very professional.
May I ask what software you're using for the 3D design? I don't like the one that I've used in the past.

Thank you, sir!

I like it when I get something close to right on the 1st pass. (I'm printing a v3 now... that doesn't have the connected feet... It's something from the sketchbooks that others have approximated in the past x years, but slightly different.)

Software? Ha! I've spent 95% of my time in Tinkercad the past 3+ years.

For 95% of what I make, it's the faster way for me to lay things out. Plus, my brain works in the object-oriented way it operates.

We continue to be surprised at just how much I can do in it. And it's free and easy to use if you're teaching newbies about 3D-modeling!


I

 

[Pete B]

I always wanted to 3D print the mid and tweeter boxes for a KEF 105 inspired copy:

The Official KEF 105 Owners Registry

I have parts.

audiokarma.org

But don't have the CAD skill to do it.
Might be nice if it took a screw in flat baffle so that different ones could be cut
depending on which mid driver was chosen.

Also, the B&W 801 mid and tweeter parts would be nice. The tweeter is more of an egg shape
and requires a small format tweeter. SEAS has some small auto sound 1" tweeters that would work.

 

[plavatar]

I always wanted to 3D print the mid and tweeter boxes for a KEF 105 inspired copy.

I *love* that KEF design. There were a few contemporaries that had that look. I liked those, too, but the KEF is my favorite =)

Might be nice if it took a screw in flat baffle so that different ones could be cut depending on which mid driver was chosen.

The base design is such that resizing for different internal volumes and speaker sizes isn't hard (relatively speaking), compared to traditional construction.

I'm thinking of an intermediary step to making my 8-inch ones; my friend REALLY wants a pair of 4-6.5 inch versions. I was laying down with one of the M7 Sphericals on my chest, thinking about the front baffle/ring construction when I saw your follow-up.

But don't have the CAD skill to do it.

Pfft! You don't have the skill, yet, you mean!

Do you have the dimensions of those modules?

Also, the B&W 801 mid and tweeter parts would be nice. The tweeter is more of an egg shape
and requires a small format tweeter. SEAS has some small auto sound 1" tweeters that would work.

B&W was the case study I used in my business proposal.

I'm looking around for a parts combo at less than $200 for my friends' version.

I was going to part out a pair of Paradigm Titans, and upgrade the crossover, but he wants new parts. I told him, if we want to do it right, designing crossovers is a YUGE skill we need to learn. He decided to go down that rabbit hole. His wife is prepping for making molds. Hobbies... jeez.

 

[Pete B]

No I don't have the dimensions, I'll ask in that 105 thread.
You are looking for an 8" woofer two way with a crossover design?
You could probably find one by people on Parts Express Tech Talk but most
DIY people say not for commercial use.
Jeff Bagby (RIP) has done many designs but I don't think many with an 8" woofer.
There's an interesting one on DiyAudio by XRK971, but it uses a full range for
the tweeter.

 

[plavatar]

No I don't have the dimensions, I'll ask in that 105 thread.
You are looking for an 8" woofer two way with a crossover design?
You could probably find one by people on Parts Express Tech Talk but most
DIY people say not for commercial use.
Jeff Bagby (RIP) has done many designs but I don't think many with an 8" woofer.
There's an interesting one on DiyAudio by XRK971, but it uses a full range for
the tweeter.

Bagby = Legend (and... Javid?)

I picked the 8-inch in 2000, before I knew better, but tried to go with one that would split the difference between bass and (for lack of a better word) articulation. My side goal is a one-off using it in a 3-way with a 6.5 Paradigm pair I like, but... that's another day =\

It looks like I'm going to do the next model as a 6.5

The size of the Minimus mod cabs would work with other 4-inch drivers, if I wanted to go that route. They're a great size for desktop.

971's design: I'll check that out. I like the Elac coax/woofer pairings in their bookshelf speakers. I considered that or a full-range + the 8. I think I'm almost set on a 6.5 (ported, probably) 2-way for the first ceramic test.

I'm printing a new pair of the Minimus cabs. I needed to simplify the design for molds/casting. So, I'm experimenting with the Minimus size first.

 

[wiredbecker]

Ooh, nicely done! Did you increase the internal volume from the original Minimus rectangular design? Zilch would have loved this iteration.

 

[Maxamillion]

Very nice mod!
Upgrading the internal crossover with larger parts certainly decreases the available internal volume. My solution to the internal volume issue was to build the crossover externally in a plastic project box and attach it to the back of the stock box.
Not quite as elegant as your solution, though!

 

[plavatar]

Ooh, nicely done! Did you increase the internal volume from the original Minimus rectangular design? Zilch would have loved this iteration.

Thank you! I tried to keep the internal volume as close to original as possible (taking into account the bigger crossover and parts).

I wish Zilch was still around. I'd like to think all you elders would approve =)

I took a break to recharge and do some family things. I've got the next version for testing the casting process to print.

Muckin'-about note:

I'm sure the simple waveguide changes the sound. The highs sound 'louder' than the original M7 box, but the imaging is so much better. I'm sure, if I had more knowledge, there are crossover tweaks that would make it even better. My main goal was to time-align the voice coils (and [laughs] it looks better).

My oldest calls them 'The Babies', since they're vaguely baby-sized and are cradled in an arm just like one =P

 

[plavatar]

Very nice mod!

Thank you!

Upgrading the internal crossover with larger parts certainly decreases the available internal volume. My solution to the internal volume issue was to build the crossover externally in a plastic project box and attach it to the back of the stock box.

Correct! I was surprised how much bigger everything was. I shouldn't have been too surprised (I've upgraded a few Polks), but I still was!

Not quite as elegant as your solution, though!

[thinking]

Well, my original idea was a plate that screwed into the holes on the back that held the crossover 'naked' on the entire back. It was what I turned the one I use in the the spheres into. It looked very steampunk on the back, but it was not at all protective. For the stock cabs, yours are GREAT! If I'd have used that, I might not have gotten the inspiration to revisit my old design. So, it's a good thing I never saw your solution =)