Hoping to start a 'Finalists' build

[Paul K.]

Here's an idea you might want to consider. As I made the drawing for what I originally modeled, which you translated into a 3D version, at the top of the front half of the line the stuffing will tend to fall backwards and down into the back half of the line. You can probably come up with a couple of ideas of your own for retaining the stuffing, but here's what I did for my most recent build that has a very similar construction for its single-fold, ML-TL:



This is a 2-way system but the basic line concept is the same with the line folded once and stuffing in all of the front half of the line.
Paul

[KarlD]

Ah that's cool. I may well do that then. I was wondering about the stuffing - I thought that it might settle over time and end up down the bottom so was thinking about possibly putting a few crosses of something like fishing line in the TL to keep it fluffed up.

That's a cool looking design. Are you doing a build thread on it anywhere?

[Paul K.]

Ah that's cool. I may well do that then. I was wondering about the stuffing - I thought that it might settle over time and end up down the bottom so was thinking about possibly putting a few crosses of something like fishing line in the TL to keep it fluffed up.

That's a cool looking design. Are you doing a build thread on it anywhere?

These, the Brillante, are already built. I took them to the InDIYana event at the end of May and I'll be entering them into the Under-$200 category at MWAF on July 11/12. Here's a photo of the finished speaker:

[KarlD]

I like the finish a lot.
Will you be releasing the plans for them?

[Paul K.]

After the MWAF event I'll have a writeup in pdf format for anyone that asks via a direct email to me.
Paul

I like the finish a lot.
Will you be releasing the plans for them?

[KarlD]

I think I'm in danger of having nowhere to put the crossover.

I can't really put it in the woofer compartment I don't think. And I'm not sure it would fit behind the tweeter.

Is it a very big board?

[Jim Holtz]

I think I'm in danger of having nowhere to put the crossover.

I can't really put it in the woofer compartment I don't think. And I'm not sure it would fit behind the tweeter.

Is it a very big board?

I cut mine 7"w x 9"L out of perf board and mount it with screws in the bottom of the woofer cabinet. I've never built a TL so I can't comment on where to place it. Paul has built/designed many. I'm sure he can offer some guidance.

Jim

[Paul K.]

I often mount the crossover assembly upside down in a base I build for the cabinets, with the internal height of the base around 2", but doing that would again make the tweeter height too tall for your needs. Jim said he was able to build the crossover on a 7" x 9" board which isn't all that large, actually. I did plan ahead in the TL modeling to allow for volumes consumed by woofer, braces and, potentially, the crossover. Since the cabinet is 9.5" wide internally, you could cut a rectangular opening in the back panel about the same size as the crossover assembly, assemble the crossover on a 1/4"-thick base that's 1" larger in both width and length than the cutout, place foam sealing gasket around the opening's perimeter, then screw the base onto the back of the cabinet. There would be little volume consumed by the crossover components because part or most of their bodies would be contained within the back panel's thickness. You could also place the input binding posts in the center of this crossover base for direct wiring to them from the components. Of course, you'd want to finish the outside of the base to match the rear panel. I did exactly this a long time ago but that was before I had a digital camera, so I can't show you photos.
Paul

I think I'm in danger of having nowhere to put the crossover.

I can't really put it in the woofer compartment I don't think. And I'm not sure it would fit behind the tweeter.

Is it a very big board?

[KarlD]

Image not available

Not really anything to get excited about but I've made a start.

Cabs will be MDF but as there was room on a ply job on the CNC router some braces have been squeezed out the gaps.

I might do the TL divide out of ply too if I have a big enough off cut but the rest will be MDF. For a laugh I have budgeted £15-20 to make the cabs (excluding whatever finish I decide to go for).

[5th element]

Looking good so far hehe As you said it's a start right?

[KarlD]

Haha. [emoji2] Like I said though, I'm not going to be able to afford drivers until next year (unless I have a good turn of fortune), so I can take my time and scrounge all the timber parts so hopefully the cabs will cost me next to nothing.

I'm probably going to need to sort out the crossovers before I glue everything up though.

[5th element]

Hmm that most certainly sounds like a recipe for disaster, you're going to want to have access to the crossover once the loudspeakers are built. This is important for any fine tuning that you may wish to make and this may only become apparent after a while of listening

[KarlD]

Nah I don't mean to glue it in, but so I can get a good idea on size and layout so I can put it somewhere I can access it easily. Like on a removable rear plate.

[5th element]

Ah good good, I have seen some people put the crossovers into their semi-finished cabinets and then glue the final panel on. :O A big no, imo.

[Paul K.]

Myabe Jim would share a photo or layout drawing of his assembled crossover on that 7 x 9 base so you would have a better idea of how you might use a slightly different footprint while keeping essentially the same arrangement of components?
Paul

Nah I don't mean to glue it in, but so I can get a good idea on size and layout so I can put it somewhere I can access it easily. Like on a removable rear plate.

[KarlD]

I think there will be plenty of room at the bottom of the TL below the reflex port. I don't want to end up with miles of cable to reach each driver though.

I am a bit unsure of exactly what crossover components I can use. I don't know what wattage rating I need for the resistors or what voltage rating for the caps.

[Paul K.]

For capacitor voltages you need to use a rating of 100 volts are higher, but you don't have to go to extremes, like 600 volts. The parts list for the Finalists show Solen caps and I bet they are all 250-volt rated which is fine. Resistors are typically rated at 10 watts, and the parts list show the Lynx brand which is rated at 10 watts AFAIK. Here's the link to the page on the Finalists that has the has that parts list: http://speakerdesignworks.com/Finalists_3.html
Paul

I think there will be plenty of room at the bottom of the TL below the reflex port. I don't want to end up with miles of cable to reach each driver though.

I am a bit unsure of exactly what crossover components I can use. I don't know what wattage rating I need for the resistors or what voltage rating for the caps.

[KarlD]

I take it 100V would be the AC rating?

I'll probably end up with Mundorf resistors and their MKP caps. I think they do coils too so knowing me I'll probably just buy those too.

I can't get over the price of the 100uF caps. £40!!
Mind you, I recently saw there are Audio Note Gold/Silver oil ones for well over £1000. And I bet there are more expensive ones somewhere. It's mad. I'd be scared to solder it!

I'm not sure what is meant by steel laminate inductor. I assume that's the core being referred too. I'll do some Googling.

[Paul K.]

Here's what a steel laminate inductor looks like: http://speakerdesignworks.com/Finalists_3.html
The laminated core allows a higher inductance with a lesser amount of wire around it which also keeps its d.c. resistance lower. Whatever inductor you choose make sure its wire gauge and resistance matches or closely matches those of the inductor specified in the parts list.

A 100-uf polypropylene capacitor is going to be expensive even without using exotic types.

I take it 100V would be the AC rating?

I'll probably end up with Mundorf resistors and their MKP caps. I think they do coils too so knowing me I'll probably just buy those too.

I can't get over the price of the 100uF caps. £40!!
Mind you, I recently saw there are Audio Note Gold/Silver oil ones for well over £1000. And I bet there are more expensive ones somewhere. It's mad. I'd be scared to solder it!

I'm not sure what is meant by steel laminate inductor. I assume that's the core being referred too. I'll do some Googling.

[Jim Holtz]

I take it 100V would be the AC rating?

I'll probably end up with Mundorf resistors and their MKP caps. I think they do coils too so knowing me I'll probably just buy those too.

I can't get over the price of the 100uF caps. £40!!
Mind you, I recently saw there are Audio Note Gold/Silver oil ones for well over £1000. And I bet there are more expensive ones somewhere. It's mad. I'd be scared to solder it!

I'm not sure what is meant by steel laminate inductor. I assume that's the core being referred too. I'll do some Googling.

I usually don't take pictures of my crossovers but I did when assembling the Finalists. I also lied, I assembled the woofer circuit on a separate board which I cut off the 9" x 7" perf board I originally indicated I used. My crossovers are ugly but functional.

Curt had picked up the crossover parts during development so he broke the large value caps into smaller values. When you see 5 caps, that's actually 5 20uF caps that make up the 100uF on the mid circuit.

HTH

Jim

[KarlD]

In the UK, soil pipe / drain pipe is 110mm or 160mm.

160mm is 6.3". Would that work for the mid tunnel? I'm having second thoughts about the laminated MDF rings for the tunnel as it won't provide a very good surface around the diameter.

[Jim Holtz]

160mm would work fine.

Jim

[KarlD]

Awesome. Now I just need to find some that has been left... unattended...
[emoji12]

[5th element]

lol Karl, it can't be that expensive?

[KarlD]

Cheapest I have found so far is £24 from Tool Station. But that is for 3m lengths - and I only need 1m. Someone is bound to have an offcut somewhere I can scrounge.

I've also now found you can get 150mm ducting for kitchen extractor fans which is very cheap, white and can be got in 1m lengths but I think the wall thickness is only a couple of mm, but I could brace it 3 or 4 times inside the mid/treble compartment.

[Paul K.]

This is what you said about changing your mind on using MDF rings: "laminated MDF rings for the tunnel... won't provide a very good surface around the diameter". Are you concerned about the inner or outer diameter being a bit uneven or rough? If it's the inner diameter, once you line and/or stuff the tunnel, it won't make any difference in its performance, IMO, and if it's the outer diameter, no one is going to know other than you. If you already or will have leftover MDF to use for this, it's essentially free, isn't it?
Paul

Cheapest I have found so far is £24 from Tool Station. But that is for 3m lengths - and I only need 1m. Someone is bound to have an offcut somewhere I can scrounge.

I've also now found you can get 150mm ducting for kitchen extractor fans which is very cheap, white and can be got in 1m lengths but I think the wall thickness is only a couple of mm, but I could brace it 3 or 4 times inside the mid/treble compartment.

[KarlD]

I was concerned about the ID. I can get it even simple enough by machining dowel holes in them.

Am I going to want to line the tunnels then? Because if so then yeah mdf would be fine. I was under the impression that the only stuffing was going to be in the start of the TL as per your instructions.

See I really don't know what I'm doing!

Will there need to be stuffing in the chamber behind the tweeter?

[Paul K.]

The midrange tunnel is lined with sheet foam. This is discussed on the Finalists' website under Cabinet Construction and Listening Impressions. I suspect Curt will chime in here with more info on lining the midrange tunnel. See: http://speakerdesignworks.com/Finalists_1.html

What I told you about stuffing the woofer's TL is correct and has nothing to do with the midrange tunnel.

The tweeter, like all tweeters (other than cheap cone-type tweeters) is sealed, therefore an empty volume behind it is perfectly okay. As the Finalist was originally designed, the whole internal cabinet volume was used for the woofer and required the port at the top to tune it. With the folded ML-TL version, the top part of the cabinet is sealed off from the bottom (and you no longer need that port tube at the top).
Paul

I was concerned about the ID. I can get it even simple enough by machining dowel holes in them.

Am I going to want to line the tunnels then? Because if so then yeah mdf would be fine. I was under the impression that the only stuffing was going to be in the start of the TL as per your instructions.

See I really don't know what I'm doing!

Will there need to be stuffing in the chamber behind the tweeter?

[KarlD]

Oh ok. I haven't seen the bit about lining the tunnel. I'll have another read. I read the whole Finalists section on that site but must have missed it.

This bit -

" I then did a ¾” round over after clamping this piece to the inside of the front baffle for a smooth
transition and to eliminate the “tunnel effect” on the driver. "

... I take it means blend the diameter of the midrange driver cutout to the ID of the pipe.

[Jim Holtz]

Oh ok. I haven't seen the bit about lining the tunnel. I'll have another read. I read the whole Finalists section on that site but must have missed it.

This bit -

" I then did a ¾” round over after clamping this piece to the inside of the front baffle for a smooth
transition and to eliminate the “tunnel effect” on the driver. "

... I take it means blend the diameter of the midrange driver cutout to the ID of the pipe.

Yes, that is correct.

Jim

[KarlD]

Trial pieces for the mid tunnel.

Image not available

It might work actually...

[5th element]

Might... that looks like it'd work very well. Of course you'd need loadsa layers, but if you've got MDF in spades then that isn't a problem.

[KarlD]

It works out I would need either 20 rings for each cab in 18mm and a tiny resess in the front and back panels for it the tunnel to fit into, or I could put one 24mm ring into each and have a slightly bigger resess which could be better.

The ring with the tabs on would obviously fit between the sides and on top of the divide to keep everything rigid. Maybe two or three of those per cab.

I'm getting a little bit over excited over little progress but I am REALLY looking forward to getting these babies built! I sat listening to Coltrane - Giant Steps LP last night and with my new cartridge I am hearing so many lovely little details like what I think must have been the frame of the piano rattling and how 'wooden' the double bass was sounding and I just kept thinking - "I'm hearing all this stuff through the M12i. How awesome is it going to be with that Vifa NE149 doing all the talking!?"

I wish I didn't need food because then I could order some components lol.

[KarlD]

I'm having trouble finding the 6.8mH inductors. 15 gauge with steel laminate core. Can't seem to find them in UK. Anyone know where I can get them?

The air core ones I found arent the exact values either. They are like .2/.3mH off what they are specified at so I've not ordered any of those yer either.

[KarlD]

Man this build has stopped dead! Too busy at work to get any bits made and not enough monies to buy any components. Damn!

[5th element]

Sounds like life happened! I think we all know what that's like from time to time, at least you've got something to look forwards to when you do get the finances and time sorted It is miles better situation to be in than having the money and the time and not knowing what to do with them, providing you're not starving.

[KarlD]

This is true. No I'm not starving yet - and I've been selling bits and bobs to fund the build. Though I have spent some of that on records... [emoji9]