I'm getting ready to do a diy speaker project - it will be a pair of open baffle TB1808s for the mids and highs with boxed speakers to handle below about 150 Hz. In some respects it will have a lot of similarity to the Olsher Basszilla design. In his discussion of that speaker, Mr. Olsher said the following:
The second major issue that needs addressing in all paper twin-cone drivers is break-up resonances. For example, the Lowther cone is extremely thin to reduce moving mass and increase the acceleration factor. The flip side of all this is reduced stiffness and damping. The g forces generated due to cone acceleration in the upper midrange cause the Lowther cone to exhibit its first breakup resonance at 2.2 kHz. The cone literally decouples from the voice coil and vibrates in sections, rather than uniformly like a piston. This provides some high-frequency extension, which is further augmented by output from the whizzer cone. The first break-up resonance coincides with what has been called the singer's formant, a strong resonance in a soprano's vocal tract that allows her to project over an orchestra. Not surprisingly, the Lowther normally excels with female voice.
The second major issue that needs addressing in all paper twin-cone drivers is break-up resonances. For example, the Lowther cone is extremely thin to reduce moving mass and increase the acceleration factor. The flip side of all this is reduced stiffness and damping. The g forces generated due to cone acceleration in the upper midrange cause the Lowther cone to exhibit its first breakup resonance at 2.2 kHz. The cone literally decouples from the voice coil and vibrates in sections, rather than uniformly like a piston. This provides some high-frequency extension, which is further augmented by output from the whizzer cone. The first break-up resonance coincides with what has been called the singer's formant, a strong resonance in a soprano's vocal tract that allows her to project over an orchestra. Not surprisingly, the Lowther normally excels with female voice.
The truth is thatstock full-range paper drivers are unlistenable due to high-Q break-up resonances. The kit plans show you how to properly tame these resonances and obtain the smoothest sound possible from the Lowther and Fostex drivers. I'll also show you how to unleash these drivers' full soundstaging potential by eliminating boxy effects in the midrange. Gain many of the benefits of planar transducers by operating your full-range as a dipole radiator.
I plan in my setup to use an active crossover, and had planned to try running the full range speakers "naked". What circuit is the above referring to, and is it something I need to consider incorporating? I'm aware of the Zobel network and the BSC networks some use - is this something else? Thanks, I'd rather not pay the extra money for the Basszilla plans as I'm not building it, just something diy that has some similarities.
I plan in my setup to use an active crossover, and had planned to try running the full range speakers "naked". What circuit is the above referring to, and is it something I need to consider incorporating? I'm aware of the Zobel network and the BSC networks some use - is this something else? Thanks, I'd rather not pay the extra money for the Basszilla plans as I'm not building it, just something diy that has some similarities.
I should imagine they are refering to a "contour network" 🙂 This is generally a resistor, inductor & capacitor in paralel. The idea being that at a certain frequency the inductor & capacitor create a dip in the response, the resistor value is varied until the desired amount of attenuation is achived 🙂
Higher value will allow for more attenuation, whilst lowering the resistance will result in less attenuation.
Higher value will allow for more attenuation, whilst lowering the resistance will result in less attenuation.
Don't know how it will relate to the 1808 for sure, but FWIW, I measured about a 5db bump at 10K on the TB 1772 when mounted on a smaller OB. So, to state the obvious, that'd call for a different trap than any for a Lowther.
That bump creates a little too much shimmer on cymbols, but it certainly is more listenable than a Lowther naked and it's big peak at about 3K!!
Mark
That bump creates a little too much shimmer on cymbols, but it certainly is more listenable than a Lowther naked and it's big peak at about 3K!!
Mark
gee I dunno about the last part - I guess it depends on your partner, but some of my most enjoyable listening was done naked (OK, that's was as in ancient history
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