Project 12

Open baffle alnico speakers.

After all these years I finally found the way to make good sound.
Getting rid of the boxes and all trouble associated with their construction - the volume, stiff walls, bracing, tuning, shaping, damping, etc. -  HOW SIMPLE LIFE CAN BE!!!
I am sorry but compared to these speakers, everything I ever built before does not compare.

At the same time I  found best speaker drivers - alnico. Antique speakers from old radios from 1950's.
I used SABA GREEN  but there are tens of models like telefunken, philips, grundig, isophon, siemens, and many more.
The tweeter, 10 cm paper SABA  alnico magnet unit - has one of the best treble I had at home. Unbelievable considering its age, price and specs.

I mount the drivers on piece of wood just to hang them at the right height.
I used a solid oak plank supported by a concrete slab.

These speakers use special magnets not available any longer. Thanks to these magnets the speakers have above 100 dB/Watt sensitivity. They play very loudly from 1 watt.
The bass (3 way config) is mounted in the bookshelf. This is the acceptable compromise of "infinite baffle" size - quite finite in fact but adequate - 2,5 m tall by 120 cm wide. The shelf back plane  gives baffle separation from back wave of the bass drivers to avoid cancellations. The cancellation only occurs off-axis and that gives the fantastic effet of NOT exciting the room. The perpendicular shelves stiffen the back boards. The books serve as weights, vibration dampers and - which is important - diffusers for midrange back wave.

 The drivers are mounted from the back side and the wood is routed round at the opening.

You can see the bass unit in its position. The open baffle arrangements produces sound totally free of boooom, resonance, overhang, etc. It is very clean, precise, easy to locate in the dead center of stage.
Conventional box bass sounds terribly,  broken by comparison.

The bookshelf back  board has been reinforced by plywood..

Some experimental XO

JBL 18 inch bass competing with two 15 inch Alphard Chinese generics.

Chinese generics competing with UK legend - ATC in 15 inch category.

And the winner is ...15 inch  Altec Lansing from USA (1970's ?) Not Alnico but nevertheless great bass drivers with 98 dB/W sensitivity.
In my experience the best bass, head and shoulders above every other driver.

Answering another question: If money was no object and you would have 50 000 Euro to spend on the system, what would you have: The answer would still be : "P12 speakers and lampized Grundig 9009". Money do not change anything in this respect. I would spend the rest of the money on Audionote Kondo amplifier from Japan.

XO- Click to enlarge