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

[Steve Manning]

Thanks TEK

[sdl2112]

Well we've started into what Jon would call the "fiddley bits" stage ....... Most of the major construction is done at this point, so it's now onto things like sanding, appling sanding sealer, fixing voids, etc. One of my favorite parts of working with wood is when you put some kind of finish on it and it all of a sudden comes alive with color. Just putting a little shellac on the first set of sides made a huge difference in the way it looks. I think our color choice changes will look pretty good Jon. :T

Got the inserts in for the circuit boards so got those installed ....

[ATTACH=CONFIG]25690[/ATTACH]

[ATTACH=CONFIG]25691[/ATTACH]

With wanting to make sure that I don't have an epoxy squeeze out problem and mess up the aluminum trim when the sides get attached, I've opted to go lite on the amount of epoxy and add some pocket hole screws to take up the slack .....

[ATTACH=CONFIG]25692[/ATTACH]

First set of sides to get a coat of shellac .....

[ATTACH=CONFIG]25693[/ATTACH]

[ATTACH=CONFIG]25694[/ATTACH]

Seriously good work Steve...and you keep your garage so clean at the same time. :T

[Steve Manning]

Seriously good work Steve...and you keep your garage so clean at the same time. :T

Thanks Scott ..... the trick is using a leaf blower at the end of the day. I'm sure the neighbors wonder what's going on with a cloud of sawdust blasting out the garage door.

[JonMarsh]

Thanks Scott ..... the trick is using a leaf blower at the end of the day. I'm sure the neighbors wonder what's going on with a cloud of sawdust blasting out the garage door.

So THAT'S the next tool I need, heh? :W

[Steve Manning]

So THAT'S the next tool I need, heh? :W

Yep ..... unfortunately is doesn't work too well for dusting in the house though :B

[sdl2112]

I guess I need a bigger one.

[dar47]

Man Steve, screwed and glued your not leaving anything to chance. Very well sorted and your getting there!

[Steve Manning]

Man Steve, screwed and glued your not leaving anything to chance. Very well sorted and your getting there!

I think I could be a little OCD ..... maybe .... sort of? That, or Jon's rubbing of on me with his more is better philosophy ...... yeah, I'll go with that.

[JonMarsh]

That's right, blame any of the weird stuff on me, and take credit for the awesome build quality...

Hmm. Can't find anything wrong with that idea from your perspective.... 8O

[Steve Manning]

That's right, blame any of the weird stuff on me, and take credit for the awesome build quality...

Hmm. Can't find anything wrong with that idea from your perspective.... 8O

I thought you might see the logic in it

[JonMarsh]

While doing a variety of online driver research yesterday evening I also came to the inescapable conclusion (supporting Ergo's earlier claim) that the C18EN001 has become a unicorn. That is, a mythical creature not available to mere mortals.

As I only have one pair of these, and have two pairs of cabinets in progress for this project, that does pose some unfortunate difficulties, but possibly not insurmountable ones- especially since I'd hoped this project could be of more use to others.

Enter stage left, another driver which I hadn't come across until yesterday evening... (Geez, I think I need to get out more; but actually I get out on the web a LOT!)





Seas MR18REX/H1669

One might say this is sort of a reed cone conventional basket and magnet version of the C18EN001- I've checked the mounting mechanicals, and they appear compatible to 2 decimal places (well, you know what I mean- to one mm anyway) and the tweeter response looks very similar, and the woofer appears to be even more sensitive, but longer throw? (Not really believeable, but who knows- still the surround is designed for midrange use) so I think we have a chance.





As a "bonus", it costs only about 40% of what the C18EN001 goes for....

I'm also investigating an interesting lower cost alternative for the woofer... Still have some leg work to do on that.

[Steve Manning]

Has anyone made contact with Seas to see what's up with the C18EN001?

[ergo]

I'll inquire from Audiohobby.eu when I go pick up my Minerva crossover parts. Last time Seas said to them that backorder wait time will not be less than about 6 months... but that was back in end of the 2015. Afaik they did not give a definite 'we'll never make these again'. So there is some chance I guess that they's reconsider.

Seas MR18REX/H1669 - I've been checking these myself too. After Minerva completion I do need some taller floorstanding speakers for the family room and these with a dual woofer backing them in low end could be one option indeed. Been waiting to really hear Minerva's results before jumping in on similar drivers.

[JonMarsh]

Been waiting to really hear Minerva's results before jumping in on similar drivers.

Very understandable...

My listening to the one to date indicates a very listenable relaxing speaker with good presentation over a large area.

A six month backorder time is pretty weird, though- any reason given?

That's one of the tricky aspects of this hobby- sourcing cool stuff that you can actually source over time!

It's like the mid woofers I'm looking in to from Motus Audio- really neat designs, great pressed paper cones, underhung voice coils- but will they be around?







BTW, these are NOT less expensive than the Wavecors.... nice motor, though, and they have a very promising looking 6.2" and 7" model also - have some of the smaller ones on order already, should be here Friday.

[Steve Manning]

Spoke with Madisound and apparently the C18EN001 is getting an update. They are not sure when that is supposed to be finished.

[JonMarsh]

Interesting Steve... not sure, as in, this year? That's good news- guess we should just sit tight unless we really want to do a budget build, too, with the MR18. I wonder if it's an "improvement" or to to fix a quality or consistency issue with the current version? I wouldn't be surprised if they got feedback from a key vendor, "We could really use this, if you'd just fix THIS, (whatever that is) otherwise, no-go".

[Juhazi]

My guess is that simply the sales of C18 was too low to be profitable. Perhaps they will run a new batch because Minerva is getting so incredibly popular! Try to sell this design to Madisound and some European house?

[JonMarsh]

My guess is that simply the sales of C18 was too low to be profitable. Perhaps they will run a new batch because Minerva is getting so incredibly popular! Try to sell this design to Madisound and some European house?

:rofl: :rofl: :rofl: :rofl: :rofl:


Now, lets remember, Seas had a system design promoting this using a Hypex plate amp solution along with the 10" LROY Seas sub driver, which Madison was promoting, and I think even showed at RMAF last year. OTOH, looking at the crossover design for that, I wouldn't say it was "fully optimized". But then, maybe someone wouldn't say that about ours? It's all relative. But that Madison sponsored design sure did disappear pretty quick...

Unfortunately, I don't think HTGuide will ever have the popularity to budge the needle on sales of any one specific driver in a meaningful way for any vendor...

Now, the MR18 may have some real possibilities as regards bang for the buck, but we always have to remember that a complex three way crossover (which this driver requires) is in no way a budget oriented solution...

Still, if we can target the Compact Evolution One performance in some meaningful way, at a much lower price point, it ought to be interesting to a few people here and there, though I doubt it will ever get built in the quantities that something like the Statements do...

[Steve Manning]

Round one of the connectors ........ Got all of the holes drilled for the binding posts on the crossover section. The ones for the cabinet will be a different flavor, one for each of the drivers.

[Steve Manning]

Got the first batch of trim buffed and sprayed with clear coat ......



Sanding and sealing also continues .......



Bits yet waiting for their turn .....

[JonMarsh]

Is this guy good or what? :T :B

[---k---]

Is this guy good or what? :T :B

I'd say better than good.

[CraigJ]

I'd say better than good.

I second that, most impressive. Perhaps you can bottle and sell some of that OCD?

[JonMarsh]

I second that, most impressive. Perhaps you can bottle and sell some of that OCD?

well, I hear that it's not legal in a number of states, not to mentions states of mind; besides, somethings are worth cornering the market on! :W

[Steve Manning]

Thank you gents, your too kind ..... I think if I could sell the OCD in a bottle, I'd be a rich man.

[sdl2112]

I very much enjoy following your build. I see a new Avatar in your future.

[5th element]

I'd be surprised if volume of orders was the reason for scrapping the C18. Remember SEAS will do custom orders for as little as 50 drivers at competitive prices. There are going to have been hundreds of sales world wide. An updated version though? That could be interesting.

[JonMarsh]

I hope so, though that would sort of turn our current parts into $500 paperweights... (of course, they'd still work as well as they do now, but you know what I mean...)

Well, I've got a lot of stuff stacked up in front of me already before I worry about the MR18...

[John Monica]

50 drivers custom orders from Seas? That's 25 pair...Anyone interested in a group buy of W18's with Be tweeters?

[JonMarsh]

wow... W18's... that takes me back a few years. Nice drivers, but demand and interest for them has dropped a bit, considering how close the RS180 gets in performance at a very affordable price.

What kind of system are you building- one of the established DIY designs for the W18, or something you plan to roll your own?

[John Monica]

Oops, my bad, I was referring to the current topic, the C18en001/me0057-08/06, not W18. No wine while writing!

What I was wishing for was a Be dome switch with the aluminum dome tweeter. Aluminum tweeters always make me grind my teeth.

Now a beryllium tweeter in a C18 with a couple of Wavcors for a nice easy impedance load would a be sweet setup.

[JonMarsh]

Oops, my bad, I was referring to the current topic, the C18en001/me0057-08/06, not W18. No wine while writing!

What I was wishing for was a Be dome switch with the aluminum dome tweeter. Aluminum tweeters always make me grind my teeth.

Now a beryllium tweeter in a C18 with a couple of Wavcors for a nice easy impedance load would a be sweet setup.

Completely agree with you on that one!

The reason there aren't a couple of Wavecor's in this build is the original need for some level of portability as well as the desire to have a more difficult load to drive for amplifier and SMPS evaluations (at work). That was on hold for a while, but now it's getting cranked up again.

It would be cool if there are some actual upgrades to the driver... But who knows. I will probably pick ip an MR18 fairly soon and run it through some tests in the original first test box. Before the end of May.

[John Monica]

Yes, of course, I've been following this thread. Haven't got the hang of pasting quotes. I'm from the "ctrl c" to "ctrl v" school. Was that DOS?

I understand you're making a torture test speaker for amps, though I question the portability aspect of those translams. (Is that perhaps a passive-aggressive thing against the weenies of sales department?) That is rhetorical, no need to commit yourself in writing....

Now, what I was getting at, if all it takes is twenty-five pairs of drivers for special orders at Seas; then, why not group order some C18(etc.) with beryllium tweeters. In the words of Jeremy Clarkson, "How hard can it be?"

[JonMarsh]

Harder than you might think... What it comes down to, Seas doesn't make beryllium dome tweeter cones. There are only two companies I know of in the world that make Be domes, one is Yamaha, and the other is a US company that supplies everyone else- Scanspeak, Seas, etc. I think if we look closely at the construction of the C18EN, one will find that that tweeter is not the standard 26mm or 29mm that those domes are available in. Then, too, it seems like there are environmental regs or some kind of regs which mean that driver builders must carefully screen and prevent the release of Beryllium pieces from the tweeter. Look at the construction of the ScanSpeak and Seas tweeters. Look also at the construction of the TAD drivers that use a Be tweeter, such as in the TAD Compact Reference One.

I don't see any way to economically retrofit that construction style to the C18EN001.

[JonMarsh]

Just ordered an MR18REX to evaluate today. It has a cloth dome tweeter.... :W

I do find that hard dome tweeters are quite sensitive to the quality of upstream equipment, and the lower the breakup frequency of the tweeter, the more so for that issue... Will be interesting to measure this and see if it's feasible to pop it into the test system without too many crossover modifications- will likely need a completely new midrange crossover, though.

That can be done....

[Evil Twin]

While doing a variety of online driver research yesterday evening I also came to the inescapable conclusion (supporting Ergo's earlier claim) that the C18EN001 has become a unicorn. That is, a mythical creature not available to mere mortals.

As I only have one pair of these, and have two pairs of cabinets in progress for this project, that does pose some unfortunate difficulties, but possibly not insurmountable ones- especially since I'd hoped this project could be of more use to others.

Enter stage left, another driver which I hadn't come across until yesterday evening... (Geez, I think I need to get out more; but actually I get out on the web a LOT!)





Seas MR18REX/H1669

One might say this is sort of a reed cone conventional basket and magnet version of the C18EN001- I've checked the mounting mechanicals, and they appear compatible to 2 decimal places (well, you know what I mean- to one mm anyway) and the tweeter response looks very similar, and the woofer appears to be even more sensitive, but longer throw? (Not really believeable, but who knows- still the surround is designed for midrange use) so I think we have a chance.





As a "bonus", it costs only about 40% of what the C18EN001 goes for....

I'm also investigating an interesting lower cost alternative for the woofer... Still have some leg work to do on that.

I believe we can all agree that the color of the MR18REX is far superior to that of the C18EN001... This alone may tip the scales.

[5th element]

Black is back...

Well Jon the SB Acoustics Be dome bucks the trend as do a few commercial speakers using the Scanspeak Be dome. I believe some magico speakers have the dome completely exposed and the SB Acoustics Be dome only has a few metal bars to help keep fingers out.

SEAS custom drivers are subject to parts availability. If you want a custom driver built on bits that they already make and use in their other models then a custom driver can be had, otherwise it would be a problem. Troels, with his JA8008, originally had an aluminium voice coil former, dustcap and wide foam surround. At the time these were the only things available, but since then SEAS had added those 8" full range drivers and the nextel line to its product ranges. The 8" full range used a fibreglass or kapton former and came with a narrow foam surround, with the nextel series using the subdued silver finish phase plug. Troels took full advantage of this when ordering his remake, the JA8008-HMQ.

SEAS Be dome is apparently on a 25mm voice coil. Scanspeaks are all apparently on a 26mm voice coil, but this could all be difference in how one rounds up/down the 1" 25.4mm. SEAS coax dome is on a 26mm former. Apparently the Transducer labs Be dome is 28mm.

[Steve Manning]

Now what would be interesting to see, is getting a hold of Magico's new diamond coated Be tweeter. 8O

[Steve Manning]

A small update on the build .......

A lot of void fixing has been on the menu of late. Not going to fix all of them that's for sure, or I'll never get done. Just addressing the worst of them, at least on the parts that will just have a clear finish on them.

Before ....





After ..... not perfect, but better.

[sdl2112]

Good job Steve...did you use epoxy?

[sdl2112]

Fyi...I ran across a little review of the Seas MR18REX.

[Evil Twin]

Fyi...I ran across a little review of the Seas MR18REX.

Interesting... most interesting...

[Steve Manning]

Good job Steve...did you use epoxy?

Thanks Scott ..... nope, for this small stuff I'm using CA glue, this specifically, http://www.woodcraft.com/product/149...thick-4oz.aspx. A lot easier than having to mix up epoxy and less waste in the process. I'll be switching to epoxy for the bigger tear out areas on the cabinets though prior to shooting the finish.

[Beau]

Found these, wonder if they are legit?

http://www.yoycart.com/Product/45753428988/

[JonMarsh]

He's selling from China, a lot of different items, and prices are high if in US dollars. I couldn't find seller ratings or any transaction history.