Hi Francois,
Read Pages 5,6 and 7 on this Thread for Mini design
The Mini woofer is 5.25" and can be used as a center but not center your refering to..
The Mini's are very good and imagine as good as or better than any mini monitor I have heard or owned and have an important advantage in another way.. The woofer dosent bottom out very easy.. In fact I can crank them well beyond what I would call comfortable levels before it starts to shows signs of being over powered.. The other small speakers I know of had a problem in this area.. Conservatively I think they sound like $2500
Have to consider nomex now.. Just thought of question for Joe
Joel
There amazing now..
My question should have been:
Based on the changes you suggest which version do you think you would prefer? Poly or Nomex?
Joel
Definitely the Nomex - it is cleaner in the area of 5-10KHz and also higher sensitivity because the cone is lighter - this translates into less heat in the VC as the VC is the same for both drivers - this is important in my way of thinking. So comparatively the Nomex should suffer less non-linear thermal distortion, NTD - but in this area it as a single driver cannot match the Elsinores, which has incredibly low NTD.
NTD is a contentious area as it has been pointed out that the change and build-up in heat is too slow to show up in drivers to show up at audio frequencies. Sorry if I am starting to sound a bit preachy, but this is one of those things that occupy my thinking a lot, maybe can even be desribed as a pet theory, but a rational one IMO. http://http://www.customanalogue.com/elsinore/elsinore_24.htm
Cheers, Joe R.
Your reasoning about thermal issues is one of the items I was thinking about when I built my actives. I used all Eton drivers. One of the reasons was they are used in the Adams Monitors which I like a lot. Thermal distortion is looked at closely in a studio, I figured if the Etons can handle what happens to them in a Adams. My house is easy.
Another thing about these Elsinores that is elegant. I gotta figure a way to build a pair. Maybe next spring.
Another thing about these Elsinores that is elegant. I gotta figure a way to build a pair. Maybe next spring.
Joel, help, I'm confused. Can you please clarify which woofers you are talking about? The one in the xover schematic is the 830860. Which one are you replacing it with?
The Nomex version is 830873. http://meniscusaudio.com/images/830873.pdf
I note something else, unlike the larger 6.5" drivers where the lighter cone means the Nomex is a bit more sensitive, but that is not the case with 5 1/4" - so other than omitting the LCR as described above, leave everything as is. But it may still be worth tweaking the main series cap to the Tweeter. The biggest difference between the drivers can likely be balanced by adjusting its value bu ear.
Cheers, Joe R.
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I note there is also a 832873, but the spec sheet, even the measurements are exactly the same as the older (?) 830873.
The original JLTi Mini used 830860 - the discussion here is changing from that Plastic cone to the Nomex version, either 830873 or 832873.
Cheers, Joe R.
The original JLTi Mini used 830860 - the discussion here is changing from that Plastic cone to the Nomex version, either 830873 or 832873.
Cheers, Joe R.
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Spent I lot of time trying to grain fill with shellac on Mini's but it's a real PITA😡
All mini's will now get clear epoxy fill or paste filler and then I'm comfortable doing one of these methods on the current Paduak Elsinore😱
Joe, is a matching MTM Mini center possible??
Thanks, Joel
All mini's will now get clear epoxy fill or paste filler and then I'm comfortable doing one of these methods on the current Paduak Elsinore😱
Joe, is a matching MTM Mini center possible??
Thanks, Joel
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Thanks for that Joe.
Joel, filling grain with shellac is difficult, because its so thin (you're using dewaxed, right?) unless you're French polishing, which is also difficult. I always liked a mix of boiled linseed oil and spar varnish (a homemade danish oil finish). You can proportion the mix to get the desired result: more varnish gives a harder finish, but you have to work faster; more oil, less durable, but more work time. You could start with 3:1, oil to varnish. Slap it on, let is sit a bit, keeping it wet, and then wipe it off thoroughly. Give a second coat and you should have a nice, built up, durable finish. If you wish, finish off with paste wax and the finest steel wool (or equivalent 3M pad) you can find.
Joel, filling grain with shellac is difficult, because its so thin (you're using dewaxed, right?) unless you're French polishing, which is also difficult. I always liked a mix of boiled linseed oil and spar varnish (a homemade danish oil finish). You can proportion the mix to get the desired result: more varnish gives a harder finish, but you have to work faster; more oil, less durable, but more work time. You could start with 3:1, oil to varnish. Slap it on, let is sit a bit, keeping it wet, and then wipe it off thoroughly. Give a second coat and you should have a nice, built up, durable finish. If you wish, finish off with paste wax and the finest steel wool (or equivalent 3M pad) you can find.
Yes, dewaxed but dissovled in Isopropyl Alcohol which I discovered gets spit out(capilliray Action).. Hard to tell this until you way into it..When Dissolved in Denaturated Alcohol it's stays in the pours but somehow my batch had to much moisture and caused clouding..
Anyway, for now I'm going to simpler grain filling and top coat with the shellac..
I will try you idea in the future though.. Thanks
Hope you do the mini's and comment on them?
Joel
A bit of a sad announcement, A. Neville Thiele has passed away here in Sydney. He was 91.
He is of course the Thiele as in Thiele-Small Parameters.
http://http://en.wikipedia.org/wiki/Neville_Thiele
He is of course the Thiele as in Thiele-Small Parameters.
http://http://en.wikipedia.org/wiki/Neville_Thiele
Sad news. That said, he certainly lead a long productive life.
Certainly his contribution to the science behind all of this cannot be underestimated.
Rest well Neville. Rest well.
Joel,
Are those Elsinores in the last two photos? Are you now employing a detachable back panel (or similar)?
I see you are using layered, overlapping panels on that build. 😀
Yes, a removable back panel and have same on my running pair. 2 Inductors will get mounted to the center brace.. 18mh is air and very large..
Pictures describes it best. 24mm ply with rabbet/mitre corners and rabbet for panels to sides..
Also sandwiched CNC steel plates for front baffle..
Waveguide mounting adjusted to 4mm
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Steel plates! Dude, that is so extreme... And so very cool! 😉
What kind of weight gain does the bring to the front baffle? Gees, I bet those things are heavy. Never thought about the resonating frequency of steel, but sandwiched between BB sheets probably makes that a moot point. What do you use, if anything, between the steel and the wood? In any case, no doubt the baffle is about as stiff and ridged as they come.
The rabbet/dado is nicely executed. I bet they assembled like a dream.
What does the shallow depth waveguide bring to the party?
What kind of weight gain does the bring to the front baffle? Gees, I bet those things are heavy. Never thought about the resonating frequency of steel, but sandwiched between BB sheets probably makes that a moot point. What do you use, if anything, between the steel and the wood? In any case, no doubt the baffle is about as stiff and ridged as they come.
The rabbet/dado is nicely executed. I bet they assembled like a dream.
What does the shallow depth waveguide bring to the party?
Thanks, I can't seem to stop getting the most detail and focus out of them..
Guessing the weight of the steel is about 15lb
The Total weight completely assembled with the 1/2 steel bases and spikes is about 170.. base/spikes are 30lbs alone
The front baffle is 6mm ply glued to sub front. Then steel attached to that with construction adhesive and 6mm ply on top of that with adhesive..
I know have 6mm of ply before I hit the steel so I can sink the woofers and waveguide 4mm.
The diameter of cut outs in the steel is 2mm wider than the prescribed cut outs as per Joe's Diagram.. This way the router bit won't hit metal as long as Router Jig is aligned perfectly. 1mm clearance
I plan to try a set with steel applied to the front of 12mm ply. Powder coat the steel and have the woofers and waveguide not flushed.. Ie) display the steel front. Maybe try a cool front colour on this pair but a bit afraid how it might look😱
Looking at all this lovely woodwork makes me want to build another pair! I had so much fun building the first ones but I would pinch a lot of your ideas for the second pair. I,d take a lot more time too, since I already have a pair to listen to. Very nice work.