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High Fidelity

Bedroom Bookshelf

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A. Design
B. Listen
C. Specs
D. Crossover

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High Fidelity

Bedroom Bookshelf Loudspeaker for late night listening

Description of this page

The Bedroom Bookshelf Loudspeaker is a compact two way acoustic suspension Bedroom Bookshelf mounted loudspeaker, built from the remains of the 'Sentinel' speaker and destined for late night listening in the bedroom. The acoustic performance is quite admirable and the size is ideal for placing on the bed head.



Speaker with new baffle


Speaker on bed head with grille


A. Designing and Building the Speaker

The Bedroom Bookshelf loudspeaker was created to investigate cone breakup on midrange drivers, and eventually become my preferred listening source in the bedroom. The speaker is virtually the top end of the old 'Sentinel' speaker with a different bass driver and a simplified crossover network. The cabinet is thoroughly braced and insulated. Crossover assembly was on a Jaycar CX-2605 Crossover PCB, using Jaycar off the shelf inductors and polypropylene capacitors.

After a period with a bare, unfinished cabinet I decided to practice my woodwork skills by replacing the front baffle, installing grilles and staining the cabinet. The results were worthwhile and produced a neat small loudspeaker with exemplary performance. They now have both the sound quality and the appearance of a high quality loudspeaker.


B. Listening to the Speaker

Originally the sound came out as rather thin sounding, seemingly lacking midrange. Significant improvement was made to the speakers by doping the cones - have a look at the sheen on the bass driver cones in the pictures. The speakers now have a clean musical sound, as I prefer. The bass response seems adequate for such a small speaker, and is quite effective for late night listening in the bedroom.



Speaker Original Baffle


Speaker on Shelf


C. Specifications of the Speaker

Specifications : Two Way Acoustic Suspension Bedroom Bookshelf
Dimensions : 155mm(w) * 165mm(d) * 280mm(h)
Enclosure Voume : 4.7 litres braced and lined
Frequency Response : 120hz-18khz @ -3dB
Efficiency : 88dB SPL @ 1W @ 1 metre
Impedence : 7.5ohms typical
Power Handling : 20W rms
Crossover : 2,900Hz 2nd Order Linkwitz Network
Impedence Correction : Woofer and Tweeter Voice Coil Inductance
Bass Driver : Altronics C0635 100mm Paper Cone Mid/Bass
Tweeter Driver : Fosters D025N15 25mm Cloth Dome Tweeter


D. The Crossover Network



Circuit for the Crossover Network