Overview:
The 10C 77 25 10 KAP is a 10″ woofer with sandwich cone from the AudioTechnology FlexUnits series.
The sandwich cone is made from two thin carbon reinforced paper cones, which are glued together with expanding foam, using a support tool to keep the cone in the correct shape. The foam is well damped to avoid resonances in the 2mm thick, but yet light weight cone. It’s coated with a thin ultraviolet protection coating to avoid discoloring of the cone. The cone is extremely stiff and plays without breakups in the recommended frequency area and it present a fast, uncolored and distortion free bass.
The KA system is implemented in the sandwich cone drivers and is a mixture of Kapton and Aluminium voice coil bobbin. This means that the driver acts as a pure Kapton voice coil driver as long as the voice coil is within its linear working area. It also presents a very low mechanical resistance, which allows the driver to play bass with authority, even at low levels.
Customers are able to make adjustments regarding the T/S parameters as well as the physical parameters – FX. Voice coil winding height, magnetic gap height and magnet sizes. This is an unique possibility for DIY:ers.
The high ventilation factor through the centre pole piece, under the rear suspension and the perforation to the voice coil, are naturally kept intact, enabling the moving system to accelerate without any compression.
AudioTechnology spec sheet: FlexUnits 10C772510KAP
T/S Parameters:
Nice match between the two driver samples. Higher Fs and Mms than the manufacturers specification.
(click on picture to zoom)
Impedance:
(click on picture to zoom)
Free air impedance measurement:
Sample 1 = Green
Sample 2 = Blue
A resonance can be seen at 1.9kHz.
Frequency:
Frequency measurement conditions:
The woofer is measured mounted in a 55 liter enclosure with the following conditions:
Baffle size (WxH): 33×78cm
Driver position: Mounted on center-line with driver unit center 35,7cm from the top of the baffle.
Mic position: On-axis 0.5m distance and on-axis near-field (3cm from dust-cap).
Smoothing: 1/24 octave smoothing applied.
0deg on-axis
Sample 1 = Blue
Sample 2 = Red
Near-field measurement.
0deg on-axis
Sample 1 = Blue
Sample 2 = Red
0.5m measurement.
Cone break-up at approximately 1.9kKz. The cone break-up seems to be less pronounced when going from near-field to far-field.
(click on picture to zoom)
0deg = Blue
15deg = Red
22.5deg = Green
Left: Sample 1
Right: Sample 2
(click on picture to zoom)
30deg = Blue
45deg = Red
60deg = Green
Left: Sample 1
Right: Sample 2
Frequency measurement summary:
Smooth frequency response within its usable frequency range. Slightly different frequency response at higher frequencies as well as cone break-up behavior between the two driver samples.
Distortion:
Measurement setup:
- Woofer near-field measurement at 3cm from dust-cap
- Frequency Range Mid-woofer: 50-2000Hz
- Baffle size WxH: 33×78cm (baffle edge round-over r=19mm)
The distortion measurements are done in near-field and the amplifier output level was adjusted for each driver so that the fundamental is 85dB, 90dB and 95dB at 1m. This setting simulates normal, medium and high listening levels.
85dB @ 1m (click on picture to zoom)
Left: = Sample 1
Right: = Sample 2
90dB @ 1m (click on picture to zoom)
Left: = Sample 1
Right: = Sample 2
95dB @ 1m (click on picture to zoom)
Left: = Sample 1
Right: = Sample 2
Distortion measurement summary:
Low second-order harmonics compared to the odd order harmonics or if you look at it in another way, high odd-order harmonics compared to the second-order. 😉