Another New OB Design

[ttan98]

Over the last 6 months or more I have been learning how to build an OPEN BAFFLE speakers and since then build one or 2 prototypes based on this. The sound has been promising.

The speaker designs that gave me some inspirations include those from Magnetar,MJK,Clayton(Emerald Physics), Bastani and lastly and not the least Lynn Olson's forthcoming new no compromised speaker designs.

Except the last one all the speakers build on these designs above seem to measure well and sound good too. Some designs seem to based on no compromise approach while others are based on 2 way design. Each has its advantages and disadvantages.

My proposed design lies between the no compromise design and the 2-way design. A conservative design would look something like this TMWW configuration, all drivers must have SPL of at least 95dB at their operating frequency. A design based on this would work quite well and will sound pretty good. After looking at Clayton's design based on TWW configuration. I think the TMWW design can be trimmed back yet not compromised on the sound.

My new design is based on TMW,
T- Tweeter based on compression driver eg. BMS and
8 sound horn
M- Mid acts more like midrange and mid bass,
eg. eminence delta 12A(12in), operating
between 41 and 5kHz, can pick cross-over at around
1.5-2.0K between Tweeter and Mid.
W- woofer based on eminence 15in, delta15LT, with
Qts=0.58 not that high, fs=40Hz
The cross over between the Mid and Woofer is
simple inductor placed in front of the woofer.

The TMW looks more like 2.5way speaker.

I will be using digital X-over based on DCX2496 and I can equalise the lower end to bring the bass down to start rolling off starting 50Hz or lower.

This design saves one driver per side and can easily biamped. It has the advantage of Clayton's design but does not suffers the low X-over at 1 Khz between T and W.

Like any design it is a compromise, one possible one is the M cone breaking up at around 3-5Khz. Matching of the 12A and 15LT can be a problem. steep x-over between tweeter and Mid because of mid's cone break-up

Any inputs on this design is welcome esp. outlining the shortcomings before I start to purchase the drivers or abandon the design.

Thanks for reading.

[mashaffer]

Personally I would prefer a mid that could go higher (5kHz minimum) and a woofer with higher Qts but that is a matter of taste I suppose.

mike