"Endorphin" P-17 speaker project
This is my walk-away message - a simple design for everyone to copy if you want.
The photo says it all: this is a design of ultimate simplicity. No
curved shapes, no special tools required, no special skills required.
They are doable in one weekend from leftover MDF and plywood.
This will be the LAST loudspeakers for most people who will try them.
baffle size - width 50 cm (45-60)
Height 140 cm (130-150)
Baffle thickness: 40 mm (35-60)
Tweeter mounting height: 100 cm
Midbass mounting height: just above tweeter
Bass mounting height: rather close to the floor, but not any closer.
Backpack-bass box size: width 5 cm less than baffle, height 80 cm, depth 50 cm.
BASS: Altec Lansing Alnico bass B416(a, b or c, 8 Ohms)
Alternatively: any bass of size 15 or 18 inches. Maximum value Fs is 37 Hz, optimal is 25.
Maximum Qts is 1, optimum is 0,35
Minimum sensitivity dB/1m/1W is 97 dB
Magnet should be alnico, but any other will do as well.
Saba Grun 20 cm Alnico midbass, or 18/22 cm oval of same breed. Other good ones are isophon ovals. MUST be alnico magnet type.
Tweeter: Saba Grun 10 cm open basket tweeter
Bass arrangement: in openback enclosure (folded open baffle) just a box without the back wall.
Mid and tweeter on open baffle.
Mid must be physically in front of the tweeter by a distance of 12 mm.
Use a 12 mm plywood (not shown in the final speaker photo - my mistake)
This is for time alignment of the mid to tweeter.
Hey mister! and where are the mathematics, parameters, anechoic chamber test results?!
Ok, sez I, I have done the homework for you, you can just trust me on that one. Or you are on the wrong website.
Cost of one pair:
4 sabas - 150 Eu
2 Altecs: 500 Eu
Carpentry: 300-500 Eu
Parts and wires: 100 Eu.
1200 Eu should be enough.
Savings: generic bass in place of Altec costs 100 Eu a piece
Oval Saba is cheaper than a round 20 cm by half
Carpentry without veneer may cost 200 Eu
Driver offset plywood spacer.
The XO is easy one.
The bass is cut-off where it starts overlapping with Saba.(300-400 Hz with 2nd order electric filter)
I use iron dust core for bass because air core is a wrong concept for this application, trust me.
Saba is hipass filtered to protect it from physical damage (without filter saba can only handle 2 W of bass)
The dirty and spiffy top range of the midbass Saba is filtered by a
0,39mH coil. Use freely 0,20 till 0,68 to your taste of "presence".
The tweeter may be first order 4uF or even better - 2nd order - 4uF series, o,39mH coil paralell.
No resistors in this XO. Remember I only like resistorless crossovers.
This way I will no longer need to answer the emails from you - dear readers : "which is the best design for me that I could copy from your designs ?"
Well - now you know it - THIS IS THE ONE.
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 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.
Good night and good luck.