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Acoustic KN KW2201-16

Acoustic KN KW2201-16

Acoustic KN is a small company, specialized in repair and production of limited quantities customized loudspeaker drivers.  KN stands for Krassy Nedelchev - an experienced audio engineer, formerly worked for BMS company. 
This is the person I trusted for the construction and production of a bass driver, that embodies my concept for a good low-frequency reproduction. My idea was to bring together the advantages of the professional and h-fi cone drivers as far as it is possible.
The purpose of this driver is to be used as a bass unit in a compact yet powerful multy-way system. The desired impedance of the acoustic system was 8Ω using two bass units, that's why the impedance of each one was planned to be 16Ω .

Close view of Pair of Tang Band W6-1916 cone

All of the parts this driver consists, except the cone, were designed, constructed and produced by Acoustic KN. The cone is paper and is enforced by carbon fibers.

The chassis is casted of aluminum alloy and then precisely milled. The constructions is light, but very rigid, with vented area behind the spider.

The two-inch diameter voice coil former was made of fiber glass and high-temperature composite.

The strong magnet system delivers an excellent control of the whole driver - the BL factor is about 15 Tm. In addition the magnet system is vented too, allowing an extra cooling the voice coil.


Close view of Pair of Tang Band W6-1916 cone

The close look of the spider shows, that the textile nest looks a bit coarse. The vents in it allow the free air flow, when the excursion of the cone is significant.  The spider is coated with the special unguent, that fixes its mechanical properties, allowing almost everlasting consistence of the T/S parameters. In fact this driver does not require any break-in. It passed one week treatment with 6V sweep sine signal without changing the T/S parameters more, than 1-2%.

Unlike the tough spider, the cone suspension is made of soft rubber with a big acoustic losses, which terminates very well the standing ways and allows a smooth and uncommitted movement of the cone. T
The result is very low harmonic distortion at any level of power. 

My Measurements

Driver Properties Thiele - Small Parameters
Chassis material Die Cast Aluminum Alloy    Parameter Measured Datasheet
Membrane material Paper Fs 31 Hz N/A
Magnet System Ferrite Re 11.9 Ω N/A
Surround Rubber  Qms 7.9 N/A
Voice Coil Diameter 50 mm Qes 0.37 N/A
Nominal Impedance 16 Ω Qts 0.35 N/A
Sensitivity 90 dB/W/m   Vas 40 ltr N/A
Rated Power 90W Le 1.4 mH N/A

Acoustic KN KW2201-16 SPL Responce at 1m on axis and 15 30 deg off axis

Frequency response at 1m with 2.83 V input RED - on axis, BLUE - 15 º off axis, GREEN - 30 º off axis

Acoustic KN KW2201-16 Second, Third and Fourth Harmonic in 38 ltr sealed box

The second, third and fourth harmonic curves measured at 2.83V and 8V input RMS.

Acoustic KN KW2201-16 Burst decay Responce at 1m in 38 ltr sealed box

Burst decay response, measured at 1m on axis

Acoustic KN KW2201-16 impedance in 38 ltr seled box

The impedance curve in 18 ltr sealed box


I does not happen very often that the result exceeds the expectations concerning frequency response of a new developed unit. Although this speaker was designed strictly as low-frequency driver, it can be used up to 1800 Hz, which make it suitable for two-way construction systems using the proper tweeter.
The construction the KW2201-16 was designed for, is a compact (30 ltr. per unit) bassreflex.

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