This time on the test bench we have the ScanSpeak 18W/8545 mid-woofer from the ”Classic” series.
The two tested driver units are the 18W/8545-01 and the 18W/8545-00. The -01 version replaces the soon to be discontinued -00 version.
Measurement details for the two different mid-woofer versions can be found here:
(click on picture to zoom)
Left driver in picture: 18W/8545-00 (old version)
Right driver in picture: 18W/8545-01 (new version)
What’s the difference between them?
The new version claims to be an improved version of the old 18W/8545 and even though the measurements shows slightly better frequency response and distortion profile they are more similar than different from each other.
The -01 version has a new chassis that allows larger screw fasteners to be used. The old -00 version only allowed screws of 3mm in size.
(click on picture to zoom)
Left driver in picture: 18W/8545-00 (old version)
Right driver in picture: 18W/8545-01 (new version)
The new -01 version has a new spider material compared to the -00 version, but the magnet size chassis shape etc. are the same.
The -01 version has about 8% higher resonance frequency compared to the -00 version and slightly higher Qts. Both will work satisfactory in the same enclosure volume and bass-reflex tuning.
Impedance:
Blue: 18W/8545-00 (old version)
Green: 18W/8545-01 (new version)
Besides the difference in resonance frequency the impedance plot is virtually identical.
Frequency:
(click on picture to zoom)
Left: Frequency response on-axis (Blue= -00 version, Red= -01 version).
Right: Frequency response 15deg off-axis (Blue= -00 version, Red= -01 version).
Slightly higher sensitivity and extended frequency response for the -01 version compared to the -00 version.
Depending on the cross-over design, the new -01 version can most likely be a drop-in replacement for the -00 version.
Measurement details for the two different mid-woofer versions can be found here: