Minerva Monitor: "Patience my ass, I'm going to go build something!"

[Steve Manning]

looking great.... I see that interior bevel now.
Another question what is the hump for on the
bottom of the enclosure?

Jon stated the "official" reason ....... but off the book, it was a quick and dirty way to adjust the volume of the lower driver area. I just moved that around while watching the volume in Sketchup until I got what I wanted. Easier than redoing the entire cabinet. It also gives you that non - parallel side thing everyone likes.

[Steve Manning]

Remiss on vacation pictures .....

Since I forgot to post the obligatorily vacation pictures of my trip to the Pacific Northwest ..... here's a few

[JonMarsh]

Jon stated the "official" reason ....... but off the book, it was a quick and dirty way to adjust the volume of the lower driver area. I just moved that around while watching the volume in Sketchup until I got what I wanted. Easier than redoing the entire cabinet. It also gives you that non - parallel side thing everyone likes.

Darn... there you go giving away our secrets again! :B


Looks to me like you had some quality time in the Pacific Northwest, other than that one traffic jam that kind of ruined that outing and day...

[Steve Manning]

First One Done

Well the first cabinet is done ....... here are a few shots of it on the stand.

[ergo]

Very nice and I'm sure they'll get even nicer looking with the drive units in them. Great work - finish line in sight now

[scottvalentin]

Beautiful work Steve! Also love the grey speakers behind, I think I've read that thread but I'm reminded how masterful your craftmanship is!

[Carl V]

Beautiful work Steve! Also love the grey speakers behind, I think I've read that thread but I'm reminded how masterful your craftmanship is!

Agree....very high caliber.
Remind me (us) about the Provance of
that gray 3-way. Link?

[JonMarsh]

I like the black and white version Steve sent me...



This is a shrunk down version for the forum...

[Steve Manning]

Thanks guys ...... Carl here is the link to the grey's in the background.

[5th element]

Holy Moly. That black and white image looks amazing!

[sdl2112]

The black and white photo looks like it's straight out of Stereophile...:T

[Steve Manning]

Thanks on the photo guys ....... even a hack photographer like me can get a decent shot once in a while.:B

[JonMarsh]

The black and white photo looks like it's straight out of Stereophile...:T

Definitely! Uh, other than the missing drivers... But you know, you almost don't notice that!

[Carl V]

very nice all around...photography, wood working, painting etc. etc.,
and re-reading your SMAudio 1071 thread my hats off to you for
persistence & ingenuity. Naui diver...hmm, PADI diver myself.
Monterrey bay diver.

I recently listened to a friend's Original Carmel speakers...Slit Cone 2 ways.
Nice design, Nice construction. Nice Sound. However, like you and others here
at HTG well executed 3ways offer so much more...just as you observed with your
1071 impressions....similar drivers.

[JonMarsh]

C18EN002 at Solen Audio

Yesterday I found something interesting on Solen... not yet on Madisound. The latter is dropping daily in my estimation as they are tardy to make products available compared with their Canadian competitor. Maybe they need a little of that "Make America Great Again" feeling.

http://solen.ca/products/speakers/home-speakers/coax/c18en002a/

Interesting- especially as the data on the data sheet looks to be essentially and actually identical to that on the C18EN001. Perhaps a quality or yield issue with the older version of the driver?

Anyway, it's a relief to see this...

It's also showing up at some European dealers here and there...

[sdl2112]

That is a relief Jon...It would be a shame to see this driver disappear with all the work you and Steve have put in. Not to mention it's a one of a kind driver for the diy community.

Interesting...it's not even on the Seas site either yet.

Review of the old and new datasheets may elude to the issues/differences. It you look at the first two sentences, the C18EN001 describes the cones as mainly magnesium where the C18EN002 describes them as aluminum/magnesium.

[Steve Manning]

That is a relief Jon...It would be a shame to see this driver disappear with all the work you and Steve have put in. Not to mention it's a one of a kind driver for the diy community.

Interesting...it's not even on the Seas site either yet.

Review of the old and new datasheets may elude to the issues/differences. It you look at the first two sentences, the C18EN001 describes the cones as mainly magnesium where the C18EN002 describes them as aluminum/magnesium.

Nice catch Scott ..... though one would think with a different mix of materials there ought to be at least one number on the data sheet that would be different. I guess we will have to wait and see.

[ergo]

This is great news indeed. It has gained in price, but at least it's available again. (I paid 360EUR/piece in to Finns, now it is 425EUR/piece)

https://www.hifitalo.fi/seas-c18en002a

I do like the driver, so now I can continue pondering to use it for a next project for our family room too.

[blue934]

Ha. "special space time modulator" - that took me back. Wonder where that little martian is now?

[sdl2112]

Seas has officially introduced the new version of the C18EN coax.
http://seas.no/index.php?option=com_content&view=article&id=527:n ew_kin_coax&catid=41:news&Itemid=194

[JonMarsh]

Thanks for the heads up, good to see the official word and data sheet. I'll have to spend some time soon comparing this to the original, and of course I'll have to order a pair- on the surface, it sounds more like a reliability update than a performance modification, but I'd better comb the data sheet carefully before making any kind of judgement. Of course, knowing how data sheets are often created, even if there are minor differences in acoustical performance, they may have just used the old data graphs.

What I do see right away is the difference in the magnet mounting- the thick plate with multiple fingers bolted to the frame is "new", although the original frame had provision for this mounting... my engineer's suspicion is that the earliest version had this, then they eliminated it to reduce the back wave shadowing and cost, but possibly ran into mechanical stability issues over temperature range and went back to this mounting. I suspect there is no material difference in the measured response under normal conditions, unless they've also gone and tweaked the cone and surround.

We shall see...

I have a busy agenda for today already, or I'd be looking into this right away.

[Steve Manning]

Cool ...... thanks Scott. Looks like the specs are still identical, though as you pointed out before, it appears they may have added some aluminum into the mix of driver material.

[hyperducky]

Sent from my iPad using Tapatalk

[ergo]

I've done some progress (and listening too). Meanwhile I got the PE packages via my workmates with the coils as well as a 6ch class-d amp. Latter is to enable 2x 3way xover simulations with LspCAD and multi channel soundcard. So I first set it up and listened to the V1.5 xover versus the new "system voicing curve" based V2.0 xover. This convinced me that I do like the effect it has on the system, so I went ahead a rebuilt the physical xover to match the V2.0 version.

As a side note - there is a huge difference between the class-D amps and for a true long listening I would not recommend this PE amp. But for quick trials and getting a feel of the balance of the sound etc. it does work. Later switching to the NAD C390DD amp was soo much better sounding.

[ergo]

Jon, you had a link to a method of comparing the coils under different current. Would you have that at hand. I can't find that anymore... I could try to compare the Jantzen C-Coil to the ERSE ones.

[CraigJ]

I'm just curious about the status of the Minerva Monitor. Any updates?

[Steve Manning]

I'm just curious about the status of the Minerva Monitor. Any updates?

Hey Craig ...... cabinets were finished and sent out to CA to Jon ....... I think ET has hijacked Jon for the Kurosawa project. I think he has a final tweak for the crossovers though he would have to speak to that.

[JonMarsh]

Not forgotten, not gone, just not at the top of the queue. Alas, ET is a terrifying task master, as those building the Death Stars well know. At this time I am enslaved to the completion of his technological terror...

[ergo]

I've finally got my act together and finished the Minerva_EE-s. The Xovers are now inside the box and nice terminals replace the wire mess coming out of the box and a component piles next to them. My wife unit appreciated that step a lot

Now on to the next projects - ie Ardents from speakers front.

[Steve Manning]

I've finally got my act together and finished the Minerva_EE-s. The Xovers are now inside the box and nice terminals replace the wire mess coming out of the box and a component piles next to them. My wife unit appreciated that step a lot

Now on to the next projects - ie Ardents from speakers front.

[ATTACH=CONFIG]27069[/ATTACH][ATTACH=CONFIG]27070[/ATTACH][ATTACH=CONFIG]27071[/ATTACH]

Looking good Ergo .... hopefully one of these days Jon will get some time so he can do the same with the crossovers here.

Scoring points with your wife is always good ..... especially for the next project.

[JonMarsh]

That day is coming- working on pulling the last of the simulations and measurements together and setting up a new BOM for Steve and I to work from. Already ordered crossover caps, mostly Obligatto, though I'd also gotten some of the Jantzen aluminum for the tweeter circuit. There's been so much going on in other areas this is more like an archeological effort than design at this point- my short to medium term memory only has so much capacity, fortunately it's all down on disk... distributed between three computers!

[Steve Manning]

Not forgotten ....

Just to let you know, some progress is still being made, all be it slow!

Crossover work is underway as well as wiring harnesses from the stands to the cabinets.







At this point I have about 2/3 of the crossover components on hand. A few more caps and the resistors have yet to be purchased. Placement is of course is random at this point.

[cochinada]

That wiring alone is by itself a work of art! ;x(

[5th element]

That wiring alone is by itself a work of art! ;x(

I know right? It's beautiful and an inspiration to us all!

[JonMarsh]

And that'a why Steve has been a key member of "Team Minereva" all along...

For reference, here's the updated crossover BOM as we've been purchasing for the crossover:

[cochinada]

Boy oh boy! That's a very complex crossover, specially the midrange section. 8O

[Steve Manning]

Boy oh boy! That's a very complex crossover, specially the midrange section. 8O

You are talking about one of Jon's designs here. :W

Thanks for the kind words by the way gents.

[JonMarsh]

Hey, it's not all that bad... problem is, there are issues to be worked!

This is the design layout crossover in Altium Designer- note that there are necessary impedance conjugate networks and load stabilization too- and the overall LPAD is implemented in a different way that works and makes for a nice input impedance and better network values.

Everyone is welcome to do their own take on it, of course- I can provide FRD and ZMA files.





Its come a little ways since the earliest tests...

[Carl V]

Looking good on all fronts....Wiring, design, ambition & photography.

[Steve Manning]

10 lbs of .... in a 5 lbs bag!

First crossover board is done, assuming I put everything in the right place that is. This is a great exercise if you like jigsaw puzzles! Second board should go a little faster now that I know everything will actually fit.

[ergo]

Very nice! Not a lot of real estate left over so I imagine it took some head scratching to achieve this.

[BobEllis]

Yep, that's a Jon Marsh crossover.

[Steve Manning]

Yep, that's a Jon Marsh crossover.

As well you know ..... but the man does it the right way!

[Steve Manning]

Very nice! Not a lot of real estate left over so I imagine it took some head scratching to achieve this.

Thanks Ergo. Yep, lot's of head scratching and shuffling of parts.

[JonMarsh]

Yep, that's a Jon Marsh crossover.

Strictly speaking, this is a skilled Steve Manning packaging of a Jonmarsh crossover!

And lest one be too harsh, it looks a lot roomier and more relaxed than my Ardent crossover's that fit in their tiny base!






The Ardent's had higher crossover points for the woofer to midrange- by nearly an octave, and didn't need some of the elliptic style networks that the Minerva does to make the drivers play nice together, especially the midrange! Or those big 120uF capacitors!