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High Fidelity

Jaycar Stand Mount

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


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Worthingtons Workshop

High Fidelity

Jaycar Stand Mounted Loudspeaker

Description of this page

The Jaycar is a compact two way bass reflex loudspeaker with superior acoustic qualities, capable of exceeding the performance of well known commercial speakers. It has been designed to use only Jaycar components as being a suitable design for publication.

The finished speaker in the lounge room

The speaker front without the grille

A. Designing and Building the Speaker

This project began as a demonstration of the use of current Jaycar drivers to produce a high fidelity loudspeaker system suitable for publication and use as a Jaycar kit. The performance is the equal of the High Performance Stand Mounted speaker published on this website. The enclosures are simply made using rebate joints throughout with the main timber being Five Ply available from Bunnings. It gives a better appearance when sanded down and stained.

The cabinet has the same dimensions as a Jamo Studio 120 speaker. The baffle is a piece of 18mm pine measuring 400mm high by 200mm wide, with the mounting holes cut using a circle cutter jig on a plunge router. Both drivers were flush mounted, requiring two applications of the router at differing diameters. The drivers were hidden behind the grille by deep colour staining of the baffle. The bass driver is sealed with speaker sealant (Jaycar CF-2762) to prevent leakage. Note the rectangular cutout for the tweeter terminals.

The drivers are from Jaycar - The woofer is a Response 5" Shielded paper cone bass/midrange (Jaycar CW-2192) and the tweeter is a Response 25mm using a Titanium Dome and Ferrofluid magnetic damping (Jaycar CT-2007). The bass driver was chosen due to suitability for this volume of enclosure and the tweeter due to the low resonance frequency. The port is a 50mm diam, 111mm long cardboard tube and the crossover network is a 12dB/octave Linkwitz-Riley at 3410Hz, designed from an Excel spreadsheet I wrote.

All components are within 1% of the values from the calculations - note the measured values written on the capacitors. The tweeter section has a 3dB attenuator for level and impedence matching. Voice Coil inductance equalisation is applied to both drivers. The circuit board is a Jaycar CX-2605 and the Jaycar PT-3006 speaker terminals screw down tightly and will take either cables or plugs, in preference to spring loaded terminals.

The crossover network is placed in the ceiling of the enclose to avoid space conflicts with the port. I have mounted it on two wooden rails, which spaces the underneath soldered joints away from the internal wall and adds rigidity to the enclosure. The side walls are also strengthened by cross braces at the height of the centre of the woofer. Acoustic Wadding (Jaycar AX3694) is cut and applied to the back and sides of the speaker as per the image. Also note the solidity of the cabling to the drivers.

The speaker was finished with the application of a grille and grille cloth. The grille is a 1/4" fibre board sheet, cut out with circular holes for each driver and close mounted to the baffle on four speaker grille clips (Jaycar CF-2761). The grille cloth (Jaycar CF-2752) is acoustically transparent and glued to the rear of the grille using a Selleys spray glue and temporary staples to allow the glue to set.

Drivers mounted on the Front Baffle

Grilles mounted on the Front Baffle

B. Listening to the Speaker

The speaker underwent testing in the lounge room, stacked above my set of Fllor Standers. They have a clear midrange and treble, plus effective if not deep bass. A-B Testing against the Bowers & Wilkins DM-303 bookshelf model reveals much better definition and sound staging, plus the transient response and minimal overhang to reproduce cymbals effectively. Both human voice and piano are portrayed with exceptional clarity.

Crossover Network mounted in top panel

Wadding applied to Speaker interior

C. Specifications of the Speaker

Specifications : Two Way Bass Reflex Stand Mount
Dimensions : 400mm(H) x 200mm(W) x 250mm(D)
Bass Enclosure : 13L Braced and Lined
Frequency Response : 50-20,000Hz @ -3dB
Resonance : 55Hz
Efficiency : 88dB SPL @ 1W @ 1m
Impedence : 6.0 ohms typical
Power Handling : 50W rms
Crossover : 3,410hz 2nd Order Linkwitz Network
Impedence Correction : Woofer and Tweeter
Bass Driver : Response 125mm Bass/Mid Paper/Poly Cone (Jaycar CW-2192)
Tweeter Driver : Response 25mm Titanium Dome (Jaycar CT-2007)

D. The Crossover Network

Circuit for the Crossover Network