SEAS W17EX001 + ScanSpeak D2010/8513
Copyright 2005 Troels Gravesen

CROSSOVER    CABINET   MEASUREMENTS   SERIES-CROSSOVER 


SEAS W17EX001 - ScanSpeak D2010-8513

This speaker is derived from a well-known commercial design and I modified the crossover for Johnny, who had build the speakers and I was positively surprised by the good sound from these drivers - even the 8513! The W17 drivers are probably very hard to find these days, so this file will soon be listed in the vintage section.

The Crossover


Original crossover for W17EX001 + D2010/8513.
All coils should be below 0.3 ohm.

Cabinet:

Use the TJL cabinet. Vent = 72 ID x 200 mm or 67 (ID) x 170 mm and tilt 5 deg.
Use same driver placement as for the TJL2W.

Measurements

Left: SPL response. Very flat indeed, be prepared for a somewhat bright sound. I suggest also trying 5R6 and 6R8 to the tweeter. Red/blue = plus/minus impedance smoothing circuit. Read below.
Right: Impedance plot. Red = with crossover as seen above. Blue = with impedance smoothing circuit: (1 mH + 14.7 uF + 10R), placed cross input terminals.

New series crossover

After having had Johnny's speakes for some days it appeared that there were more to these drivers than a crossover quite closely resembling the original layout. Having a very flat response the sounds is somewhat bright and piano wasn't quite right, sometimes resembling the sound of a harpsichord and also some excessive emphasis on shh.... sounds from vocals. I thought I'd try a radical new design and see/hear what could be done. One thing was trying targeting the BBC dip usually giving a more natural balance to most instruments and vocals and another thing hearing what a series crossover would do. Hence the W17EX/8513 crossover below.


W17EX001/8513 mkII, series crossover.

Left: SPL response, here without the midrange notch filter.
Right: Red = series filter. Blue = parallel filter.

Left: Red = series filter. Blue = series filter with midrange notchfilter. Maybe you think this looks quite dramatic, so let's take a look at the
200-3000 Hz range:
Right: Not quite as dramatic this way. A 1-1 dB attenuation in the very critical midrange. Depending on the actual recording this may hardly be audible, but listen careful to piano and you may discover that a more natural balance is obtained.


Green straight line inserted to resemble the BBC dip. Quite close.
No further comments. This is where I want it to be.

Thanks to Johnny for lending me his speakers.