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.
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.
Circuit for the Crossover Network