The driver units used in the “Sequence Three – Grand Reference” 3-way loudspeaker:
Here I will use the RAAL 140-15D Ribbon Tweeter. This is a ribbon tweeter that many people regards to be one of the best ribbon tweeters on the market and it’s supposed to have very low distortion compared to other ribbon tweeters. Time will tell if it’s true or not and I will release extensive measurements to evaluate the claims.
Here I will use the AudioTechnology C-Quenze 15H-52-12-06-SDKM. This is the mid-range version of the 15H 5” mid-woofer and it has a special rubber mid-range surround. This is the “over-hung” version with a Kapton voice-coil former. According to AudioTechnology the “over-hung” version of the mid-range has a bit more detailed mids and “monitor” characteristics as well as higher sensitivity compared to the “under-hung” version.
Here I will use the AudioTechnology Flex-Units 10C-77-25-10-KAP. This is a 10” driver with a woofer cone made from two thin carbon reinforced paper cones. The result is an extremely rigid and stiff cone. The kapton voice-coil former is laminated with aluminium foil and presents a very low mechanical resistance, which allows the driver to play bass with authority, even at low levels.
For further details see manufacturers website:
RAAL 140-15D Ribbon Tweeter
AudioTechnology C-Quenze 15H-52-12-06-SDKM
AudioTechnology Flex-Units 10C-77-25-10-KAP
Driver unit picture gallery:
The woofer weighs about 8.5kg and is very robustly built. It has a large ventilation hole through the centre pole piece allowing for a compression free ventilation of the voice-coil. The ventilation hole is covered by foam.
The mid-range has the special rubber mid-range surround with an unusual looking shape. The mid-range also has a similar ventilation of the voice-coil, as the woofer.
All the “Sequence Three – Grand Reference” driver units showed together. Note! the huge magnet size on the woofer compared to the mid-range, which also have large magnet considering its size.