'Jubilo' 3 way active loudspeakers, construction diary

[Zeverin]

Hello everybody.

I plan to share with you the construction of my new loudspeakers called 'Jubilo'.

Some time ago, I asked for some advices and opinions, which you can see here:

Advice needed to build new 3 way active system

Please forget the cabinet model presented there.

I started the construction of the loudspeakers back in January so in the first posts I will update the construction progress up to is current status. After that you might expect slow updates.


The drivers are:
Tweeter: Seas 27TBFC/G
Mid: 18Sound 6ND430
Woofer: Dayton RS270

The loudspeaker will be made of to separate cabinets. One with to woofers, and another on top in MTM configuration. The cabinets will be placed very closed together, so that the final format will be WWMTM.

Why two cabinets? well, first it will allow to place the mids and tweeters in a less smaller baffle, reducing baffle difraction. Second in the future I will be able to change the cabinets indenpendently of each others.

The crossovers remains the DCX2496. The amplifiers maybe A500 also from behringer. I still don't have one solution for the 6-ch volume controller

[Zeverin]

Since I wanted the cabinets to be curved, I needed to use a CNC that I was able to find neer the place I live. This pictures were taken in 2009-12-28.

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In the last two pictures is possible to understand the final shape of the enclousure.

[Zeverin]

It tool a few days after to bought the adicional wood. I needed wood for the internal bracing, for the front baffles and back of the box, soo I used 19 mm MDF (3/4"). I also needed to create that curved side wall of the loudspeaker. Insted of cutting lots of pieces with the shape wanted with the CNC and stack all them on top of each other, i.e., several layers ($$$ being the reason not to do it), I used MDF with 3 mm (1/8") in the side walls, using 6 layers. Pictures will so better this technique.

First the pieces of the internal bracing (2010-01-17):

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[Zeverin]

I just love to cut wood
2010-01-23
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[doug20]

The drivers are:
Tweeter: Seas 27TBFC/G
Mid: 18Sound 6ND430
Woofer: Dayton RS270

That mid seems like a mismatch to the others? Why did you choose it?

[Zeverin]

Yes, it seems.

My initial thought was to use the Dayton RS 150. But after some discussion here and in another forum, some fellows DIYers suggested the use of this drivers. Zaph tested those drivers and posted the result in his site. If you take a look, you will see how good they measure, especially in the THD departement. In terms of cost, I managed to buy those 6ND430 for 75€ each against 44€ of the RS 150. It was a hard decision for me. But after a while I thought that I should try it. Let's see wath I can come up with.

[doug20]

Yes, I have know about about them, I do not have them but I have the 6ND410s. You do not have to convince me how much better then are over Daytons, I love them!

I guess I should have just posted, do you have a sensitivity mismatch?

[5th element]

The 18 sound only appears to be an unusual choice simply because it isn't used more often. It doesn't really fit into the catagory of pro sound, it doesn't have the sensitivity for that, nor probably the power handling.

It is actually a reaonsably efficient mid/bass, which is rare these days. Where the designer has chosen to sacrifice some bass extension for a few more dBs sensitivty. It's a very attractive option, save for the square frame, in a world where 85-86dB are a dime a douzen.

As Zerevin is going active any sensitivity miss-match will be made academic and he can fully exploit the efficiency of the midrange driver.

As to a 6 channel volume control Mouser stock a nice 6 channel pot at very little expense. I have one of these, although I am yet to use it, it does seem to be made to a decent enough standard.

Pot.

[Zeverin]

Originally Posted by doug20

You do not have to convince me how much better then are over Daytons, I love them!

Good to hear (read).

The sensitivity mismatch will be handled in the DCX or amp atenuation, I need to reduce the output of the mids and the woofers to match the tweeter sensitivity.

[Zeverin]

Hi 5th element.

Finally I'm showing something here

Can you provide more information about those volume controlers? I didn't understood how they work