Monopole, dipole, or bipole?
Here's a good article describing the pros & cons of each.
I've gone with the conventional monopole because it's generally
considered the best option for multi-channel music, and it's simpler
to design & construct. Also, being a normal monopole gives Leeloo
the versatility to be used as a normal bookshelf speaker if so desired.
Bass-mid driver. What's required is
a driver with a well-behaved response beyond 5 kHz, and a good bass
Ideally, it should also have a similar sonic signature (diaphragm
materials) to Delta. i.e Paper or polypropylene.
After also considering the Seas W15LY001 & Dynaudio 15w75 I
finally settled on the slit-paper coned Scanspeak 15W4531G00.
Tweeter. I've decided to use the Morel
Supreme 110, as used in Delta.
It's easily able to handle the 1st order electrical highpass I'll
and Delta will be getting a new, smaller tweeter.
Crossover. As with Delta, I'm using
a 1st order crossover around 4-5kHz but here with some additional
There will be no baffle-step compensation as it's designed to be
pushed right up against the wall, possibly in a corner.
The sloped baffle assists in matching acoustic centres, and also
matches the look of Delta.
Cabinet. Standard MDF materials, sloped
baffle for time-alignment at 1m+ listening distance. It will also
aid stability by moving the centre of gravity back toward the rear
of the cabinet.Height
will be such that the bass-mid driver is the listening axis, and
be similarly proportioned to Delta.
The CD-rack will be able to hold 100 or so CDs/DVDs and the speaker
& stand/cabinet be strong enough not to vibrate at all.
The internal volume will be about 6-7 litres depending on the crossover
size & stuffing . For protection it will have a removable grill
held by hidden magnets.