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ShinOBIWAN 5th December 2011 09:32 PM

Apollo Construction Diary
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Hi guys

This thread is a place to put images, ramblings and other such bits into some that will loosely resemble an attempt to document the latest(and largest) design from me to date. This is truly a statement speaker standing a statuesque 205cm tall with a considerable 75cm depth and utilising no less than 9 drivers per side. I live to build speakers like this :D

A quick note to say these are being built for a forum member here - Ackcheng. Many thanks to him for his suggestion to share all this here. Arthurs initial goal was simple - take the LGT and add a separate subwoofer tower to each side to increase the low end. Whilst that would have worked fine it did seem like a missed opportunity to create something significantly better and so came about the Apollo.


In a nutshell the Apollo is a 4way design borrowing heavily from the LGT but with improvements made on every level.
I particularly wanted to address the large center to center spacing of the LGT which was caused by the lengthy RAAL 140-15 ribbon tweeter and to a lesser extent, cabinet design considerations. This has now been greatly reduced by using the much shorter RAAL 70-20XR and tightening up the cabinets. The end result allows for a tighter MTM arrangement.
Other improvements include 5" drivers utilising a midrange specific surround profile along with custom designed 8" to give maximum impact in the mid bass region.
Perhaps the biggest departure from the LGT is the inclusion of four Audiotechnology 10" subs with Sandwich Cone which will give a cone area well in excess of an 18" driver. No doubt the low frequency extension and impact will be considerable! These 10" drivers are arranged in an opposing push-push arrangement, two in the top and two in the bottom cabinets. By directly coupling the mounting arrangements on each driver it'll take full advantage of Newtons third law causing the forces from each driver to cancel.

Drivers and layout are as follows:

S = 2x 10" AT Flexunit 10F 77 25 10 KAP
W = 8" AT Flexunit (model to be decided)
M = 5" AT C-Quenze 15H 52 06 13 SDKAM
T = RAAL 70-20XR
M = 5" AT C-Quenze 15H 52 06 13 SDKAM
W = 8" AT Flexunit (model to be decided)
S = 2x 10" AT Flexunit 10F 77 25 10 KAP

With preliminary crossover points at 60-80hz, 300-350hz and 2.5Khz.

Other small details include the use of Cerabase Classic.


The cabinet are to be constructed from MDF and Corian. Various combinations and laminations of 18mm and 9mm MDF will be used for the cabinets. And 84mm(7x12mm) thick Corian for the baffles. Corian was chosen for its ideal damping and stiffness properties that will create an excellent mounting point for drivers working from 80hz and upwards. Unfortunately its expensive and so moisture resistant(aka Extira) MDF will be used for the cabinet sections.

As the project progress construction details will be revealed in greater detail.

Finishing will be gloss black cabinet portions with polished corian baffles(kind of like polished marble)


Since this is a close relative to the LGT its typical to expect a similar sound but refined even further and with more capable extension. 15hz-40Khz will be the bandwidth of this speaker and I can't imagine there being anything in the way of compression even at beyond reference levels. This is going to be one crazy pair of speakers.

The fun doesn't end when the project is completed either because they're being shipped from the UK all the way over to HK. The shipping crate construction will be almost as involved as the speakers themselves :D

For now its early stage renders but I'll be pressing ahead at full speed with these in January. The overall size and shape is determined but a detailed model is in the works so between now and January there'll be more renders as its fleshed out.

Apollo vs. Aurora and LGT.

gainphile 6th December 2011 10:00 AM

Very nice design!

Looks like the big monster has space enough for 12 inch subs instead :)

thunk303 6th December 2011 10:19 AM

As always, inspiring and amazing. How you get all those angles to work without industrial quality machining I will never know.

Cant wait to see the final outcome and best wishes on the build.

Maybe when you are finished we can get a build price to consider :hug:

David Gatti 6th December 2011 11:53 AM

You sure don't do things by half Shin! Looks like it's going to be a truly reference standard speaker.

ShinOBIWAN 6th December 2011 12:30 PM

Thanks guys :)

Generic George 6th December 2011 04:02 PM

I joined because I couldn't stand not being able to see the pictures of your latest design. I really love your aesthetic sensibilities.

So since you are using the Raal 70-20xr, I take it you now have some sort of a formal speaker company? I know you had talked about that somewhat in an earlier thread.

ShinOBIWAN 6th December 2011 09:59 PM

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LineSource 7th December 2011 02:07 AM

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Hi Shin,

I always work to minimize the M-T-M physical spacing to reduce lobbing, and even cut off portions of the faceplate on a small diameter tweeter like the SB29RDCN toward this min-separation goal.

Have you considered a different modularity strategy with separate Woofer cabinets and separate MTM cabinets that can be stacked to create several different configurations and room multi-woofer placement options? This might provide both superior sound and a more flexible product line.

ShinOBIWAN 7th December 2011 08:56 AM

Thanks George.

Eventually that's the intention eventually but for now I seem to have work enough to occupy virtually all my spare time and so this is a distant goal but something I'm working towards non the less.

Tim F 7th December 2011 10:12 AM

LineSource is right Shin. A modular design like this would not only fill a gap in the market but also be achieveable with minimum compromise using a pc xover. Commercial may be a thought for the future, but going the modular route gets the initial R&D costs out the way while it's still a hobby & you could bring start with the MTM & bring the other parts to market at your own pace. Sub contract the manufacturing & concentrate on fit, finnish & setup.
Looks brilliant as always.

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