S9 Open Baffle Speakers

Early version of S9, circa July 2009

This build is to revisit the previous design which sounded most natural and smooth. So much that the further effort to obtain dipole bass quantity had to be scrapped.

Build process is discussed here.

Driver-baffle relationship is very important. If the inherent response is not smooth, no amount of EQ would result in natural sound.

The smoothness of this design can be summarised by differences of frequency response between on and off-axis measurements:

Update 23/8/2009
Finished dipole H-Frame woofers:

Update 10/10/2009
Tidy up the prototype XO

Update 14/6/2010
Updated active crossover topology
W-M : 300Hz, 2nd order
M-T: 2.1kHz, 2nd order

Update 17/1/2011
- Converted Analog XO to DSP
- Changed H-Frame to W-Frame subs
- Measurement from recent GTG:

Normalised plot at 0 degrees, showing directivity pattern. Here we can see that the back to back dome tweeter is the achilles heel of such setup:

Update 29/5/2011
- Converted analog XO to DSP (MiniDSP)
- Use W-Frame woofer configuration. This opens the possibility of stacking 4 woofers/side.

Update 8/6/2011
Completed S9R, an "R" or rigid-cone version of this project. Fountek FW146 + Vifa DQ25. The phase shield of the tweeter needs to be removed to avoid resonance and stored energy.

Non-normalised sonogram of S9R, 0 - 90° taken with 11° increments.
I moved these loudspeakers in to my future "audio room" here: http://www.youtube.com/watch?v=RnaTs8oK8tA.
The iPhone does not record bass well unfortunately.