|
Box EnclosuresThe closed box (acoustic suspension) and the vented box (bass reflex) cabinets are common designs for multi-way speakers. These designs can be applied to single full range drivers but their effectiveness depends on the nature of the driver. Some drivers such as Mitsubishi/Diatone 610, the Hammer Dynamics, and some Fostex drivers have enough cone excursion so that they work well in box cabinets (usually vented/bass reflex). Some references for bass reflex vented cabinets are Klaus Schiffer's page (click on Speaker D.I.Y.). Diatone/MitsubishiThe Diatone kit EIFL offers is made of particle board. It is similar to the JPO Memorial (made by Wavelength Audio), I guess, although smaller. The project on the Haute Fidelite website is TOTALLY different; it is based on Mitsubishi's original plans, and is quite complicated; essentially, it uses a box of 1/2" birch plywood inside another box of 5/8" plywood; the two boxes are separated by wooden floorboards, one to a side. In the original Mitsubishi plan, the "inside box" does not extend to the front panel; but it does include the rear panel. The French guy didn't follow the rear part exactly - in fact, in his plan, the rear panel is removable! Damping is supposed to be natural wool. This box design originated with Hiroyasu Kondo (Audio Note Japan) and the scans are from l'Audiophile. The enclosure is designed specifically for the Diatone 610 in 8 or 16 Ohm. The low end should extend to 40Hz or so. I suspect that a Pioneer PM-16 Memorial should work too. Diatone enclosure. Cutting plans. FostexMany Fostex drivers are suitable for closed or vented boxes, including the FX200 and the F200A. Fostex has many plans for vented box speakers on their website for Fostex full range drivers. See Craig Schmidt's write up The Holy Grail in DIY for the FX200 driver. Also check out the nice write up of a solid maple F200A loudspeaker. Hammer DynamicsJohn Wyckoff's Hammer Dynamics Super 12s are used in bass reflex enclosures. David WeemsBass reflex box (design by Weems) in an article using Radio Shack drivers in Valve Magazine, Vol 6, No 4, 1999 at Bottlehead.com. Includes construction plans. JordanTed Jordan has designed many great full range drivers, the latest in the Jordan line include the JX-92S which can be used in a vented box or transmission line. (Go to the Jordon website and click on Systems. RehdékoInfo from Ulli (thanks). These loudspeakers are made by Rehdéko in France. There are three models: RK 115 has one 26 cm full-range driver, RK 125 has one 26 cm full-range driver and one elliptical tweeter (12 x 19 cm). The big RK 145 has one full-range woofer (26 cm), 1 high midrange (12 x 19 cm) with REHDÉKO "saucer", one elliptical tweeter (12 x 19 cm) with supra-dispersion (with the famous REHDÉKO "saucer"). Ulli has heard all three types and says that even the smallest speaker sounds more natural than a Lowther DX in the Audiovector. Small write ups appear at Enjoythemusic.com and on the Full range forum. PHY-HPPHY-HP in a baffle and also in a box at Hans Kortenbach's page. Goodmans Axiom 80The official bass reflex enclosure in a picture, along with a four driver rear loaded horn! Moth AudioThe speaker is called the Cicada and can be viewed at the Moth Audio website. They are making some kind of Lowther driver look-alike which has a much higher Q value (Qts of approximately 0.6) which makes them suitable for use in a vented box. Sensitivity of speaker is 94 dB. They say the useable frequency range is 60 Hz to 18 kHz but don't give the 3 dB points. And of course, the Cicadas look nice (like all of their products). Herbert FuHerbert has built some nice loudspeakers. See the Double Bass Reflex Fostex. Lowther Bass Reflex SpeakersLowther drivers need help in the bass region due to their strongly rising frequency response. For a full range speaker, a rear-loaded horn is usually the best option. Some people claim good results with Lowthers in bass reflex boxes (see Classic Audio), while others who have tried or heard them find them terrible. If your room is "live" and has lots of reinforcement in the bass region, or your music taste doesn't require full volume bass, they might work. Some optimized vented box might be better than poorly-designed or executed rear horns. In any case, you will need to hear the loudspeaker in your room to get a genuine answer. Search the AudioAsylum archives (in Speaker Asylum and in High Efficiency Asylum) for "bass reflex" and Lowther, or under "Classic Audio" to find a large amount of opinion (informed or otherwise !). Recently a review appeared here at Enjoythemusic.com which was quite negative, and resulted in some discussion on the Full Range Driver Forum. (Search on Dicks, or Classic Audio). Top
|
