Ellam Dappo
Copyright 2009-15  Troels Gravesen 

Doing the Ellam 9800 and Ellam XT speakers, the idea of making a d'Appolito construction obviously came to mind. The Ellam25, 2-way, came first and for some time I've had the Ellam d'Appolito on my website as an experimental set-up.
Eventually Jesper (Ekta and Ekta Grande constructions) came by, bringing in a finished Ellam d'Appolito, thus the old file will be updated with new pics and measurements and a slightly fine-tuned crossover, now for the ScanSpeak R2604/832000 tweeter.
Jesper had used an old Ekta cabinet, turning it around and up-side down, thus a a tilted cabinet like the Ekta with a narrow front panel. The lower one-third of the cabinet had been sealed off to make an upper compartment of 22 liters - and to make a long story short, I don't think I've heard the W15 drivers better than from this cabinet. Why? Hmm... One thing is the laminated side panels made from 6 x 5 mm laminated plywood of various density. Next - and this I think is the most important thing - the depth of the cabinet. The cabs are 32 cm deep and maybe the expansion towards rear panels has something to do with the absorption of the energy coming from the rear of the drivers. Whatever, it sounds great. Using two 15W drivers we're close to the membrane area of an 8" bass driver and it very much sounds so. I don't think we can get a more powerful and deep bass from 22 liters than from these drivers.

DRIVERS

   

Download specs: ScanSpeak 15W/8530-K00  ScanSpeak R2604/832000  ScanSpeak D2904/980000

 


Speakers during crossover development.


Cabinet
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Jesper's cabs have here been transformed into a more compact looking standmount speaker.

Suggested cabinet design. We need 22 litres internal volume and a vent tuning of 40-45 Hz. I advise placing the vent to the rear and symmetrical to the two bass drivers.
The speaker needs to be lifted from the floor and a 40 cm stand plus a 3-5 tilt will provide proper performance from the usual listening position.


Crossover
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LspCAD simulation of crossover and predicted response.
Summed resistance of L2031 and R2031 should be 9.5-10.5 ohm, thus 8R2 in partslist below - and not 10 ohms.

Should you want to use the 9800 for this construction, try this for tweeter:


Purely based on simulation, but the changes are so small I dare publish.
Experiment with series resistor R1011 for best tweeter balance.


Measurements
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Left: Driver SPL @ 1 meter, 2.8 volts. Right: Impedance of drivers.


Left: Drivers' response driven from crossover. Right: Response with inverted tweeter polarity (blue).


Left: SPL/1m/2.8V. System sensitivity = 87 dB/2.8 volts. Right: System impedance. Minimum 3.3 ohms, not too bad!


Speaker Kit
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Example of Superior-Z version above. More options available w/wo drivers.

Crossover kit available from Jantzen Audio at:
contact@jantzen-audio.com

Download all kit sales presentations here. pdf file

All technical questions to troels.gravesen@hotmail.com

Here's the 9800 version parts' list:

 

CROSSOVER LAYOUT


Note STANDARD-Z caps will take up much less space compared to Superior-Z caps but stick to distance between coils.

 

Speaker wiring

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