Alien2004

ALIEN2004_BOX_FRONT.JPG

Introduction

Monopole and dipole didn't work in my flat apartment so well at the bass range. Cardioid should be better at least in theory which motivated to try. I wasn't ready to try resistance bass enclosure yet. Combination of two or more monopoles requires two active channels, and I wasn't convinced about the principle. Combination of dipole and monopole is classical and quite simple. Driver is Peerless CSX-10".

Resistance midrange enclosure is de facto standard for small mid cardioid. Horn would be much more effective but bigger of course. Resistance ports are drilled plastic (thickness 5 mm) with cotton fabric. This is not the best port structure because of vibrations and stretching. Seas W15CY001 was selected for the midrange driver.

Tweeter is Visaton MHT12 planar with metal wave guide from Hifi 262-kit.

Enclosure

Monopole enclosure is closed 70 liters, 100% filled with polyester. Dipole frame is connected to monopole with two M6 x 50 mm screws, tee nuts inside the monopole box.

ALIEN2004_BOX_BACK.JPG

Mid+tweeter arrangement is hanging on the dipole with wooden rolling pin (Piretta), dimensions 60 x 235 mm. It's possible to rotate mid+tweeter. Total height is 1150 mm.

ALIEN2004_TOP_FRONT.JPG ALIEN2004_TOP_BACK.JPG ALIEN2004_BTM_BACK.JPG

Crossover

Peak of dipole is equalized with passive R || L || C band-stop filter, L=2.2 mH 0.29 ohm (Corobar), C=147 uF, R=5.6 ohm 10 W. Attenuation at 280 Hz is 4.6 dB. Impedance of voice coil is compensated with C + R, C=22 uF and R=5.6 ohm 5 W. Passive filter is located inside the monopole.

ALIEN2004_FILTER.JPG

Crossover and other equalization is done by Behringer DCX2496.
Parameter file: Kardi01.xpc

Download DCX-Remote 1.16a to investigate this file.

Measurements

Frequency response

- measuring distance 250 cm
- time window 170 ms, smoothing 1/6 oct.
ALIEN2004_MEAS1.GIF
Bass range is slightly monopolic at 2.5 m which means that it's more cardioid close to speaker.

Summary

This was experimental project with short life time. Tweeter was bad; too much non-linearities. Midrange was ok but not very hi-res and dynamic because of mild directivity and leaking ports. Bass was the best so far (in 2004). Excellent application for small and acoustically bad environment if crossover frequency could be less than 180 Hz.

Page updated 07.11.2010

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