Full range, three-way, four-driver, floor-standing loudspeakers
February 2003

It is my ultimate goal in my pursuit of DIY hi-fi (a dream so to speak) is that all people would listen to more of good music and on good equipment. I hope everyone could afford to go to the shop and buy an all BAT or all Audionote setup. Unfortunately, this is not the case. Most people can only dream about it. And most of them don't have the skills, tools and courage to build their own.
So I am hoping that one day I will be able to design an amp and speakers which are affordable and of very high quality. The volks-wagen of hi-fi.
By affordable in my book I mean that amp and speakers should together cost circa 2000 USD. These speakers matched with ARG P-P triode amp match this criteria, not counting the time and labour cost of course.

The closest I can get to this target concerning speakers is the Project 11. It is a variation of Project 7, being more simple to build and significantly smaller/lighter.  The cost is the same, so the size of boxes is the main factor to decide for you.

The footprint of these full-range speakers is equal to A4 sheet of paper.
It took me 20 minutes to draw the boxes, and a professional carpenter made them in one day. 30 mm MDF was glued and veneered with mahogany for a total cost of 250 USD.
I bought a set of Scanspeak drivers which seemed to be the best value for the money for this particular project. For additional cost savings, I believe that Vifa 21 cm bass could be used.
See it for yourself: In my opinion, this sepeaker sounds fantastic. in a 20-30 sqm room in my opinion you can detect no limitations of any kind concerning the sound - it is as good as it gets. A comparison to 2000-4000 USD commercial speakers (however unfair)  makes the P-11 a very clear winner by KO in first round.
The total budget  was 1500 USD.

 Clicking on images will load 100k hi-resolution pictures.


These speakers were driven by 25 WPC  p-p tube amp with great clarity, speed and authority. Very rythmical sound. Bass is deep, punchy, with tons of meat.
Uncle Ted on the side of the house again. The veneer is mahogany.
The box ismade of  a 30 mm MDF.
Overall front baffle height is 130 cm. Width 27 cm. Box depth 35. Box height 103.
Internal volume is 30 liters per driver.
Q is around 0,6.

The back of the mid is of course open. I am really addicted to the open midrange. The soundstage is so good, it draws you into the very natural presentation of the spatial information. After this experience, there is really no going back to sealed midrange.
I used the LAST pair of those fantastic magical drivers (now discontinued) available in Poland. Shame on Scanspeak!
There is no provision for bi-wiring.

This is interesting driver. Linkwitz uses it as a midrange in Beethovens. On paper it has all parameters of a real bass driver. It has soft and compliant suspension and VERY soft cone. Nothing like the ultra-stiff 8565 for example.
Anyway, it sounds very good.

I decided not to flush mount all bass and midrange drivers - it looks more "macho".


You can see the 18 mm recess for time alignment of the tweeter/midrange. This was later filled with a ring of open cell foam.
The tweeter is S-S 9700 and I like it very much. It is my favourite dome at this moment in time. IMHO equal to 9900 but much cheaper. It sounds much better than 9500 or 9300. Better than 9600 too.
I was at first sceptical about the visual aspect of the ugly yellow kevlar, mixed with paper dome of the mid, but in the end  it looks OK.
The tweeter has an open cell foam around it, ala Dunlavys. I can't hear wether it improves things, as opposed to no foam, but I assume it does not hurt. The empty recess surely must have traces of strong diffraction on the 14 cm radial opening edge, but I cant hear it. Frankly, I did not bother to measure it.
The size of the opening matches that of the midrange basket.
The xo is simple and it measures very well. Impedance is quite smooth. Parts are very good but not "audiophile premium".
I spent 2 nights getting it right, but I am sure you can do better than this. Simply the result sounds so good already, that I had no desire to spend another night making it even better. Call me lazy.
Hard data:
Max power: 200W
v  Nominal impedance: 4 Ohm
v  Minimal impedance 3,8 Ohm
v  XO points:  350/3500 Hz
v  Resonant frequency: 42 Hz
v  Freq. Response +/- 2dB  20Hz-30 kHz
v  Sensitivity:  92 dB/2,86V/1m
Drivers:  Scan-Speak
v  Tweeter: 9700; 1 inch silk dome without ferrofluid
v  Midrange: open baffle mounted 18W8542 ;  18 cm paper cone on foam suspension
v  Bass: two 21W8554-00 - kevlar cone, foam suspension, separate sealed enclosures
v  Internal wiring: silver, swiss made  Oehlbah
v  All coils are air core.