I am interested in building speakers based on the Bastanis Prometheus. They have no crossover to speak of, and I don't understand what keeps the bass info from the tweeter, which is wired directly from the other driver( Eminence Beta 12 cx coaxial with Beyma tweeter). Here's the schematic http://www.bastanis.com/diy/prometheus+mkii+build.htm
Eminence calls for a 3.5k crossover with the coax and their own suggested tweeter. Thanks
Eminence calls for a 3.5k crossover with the coax and their own suggested tweeter. Thanks
Hi,
what makes you think it´s the 12CX from Eminence?
Looking at the datasheets and the FR in particular I´d guess it´s more like the Delta12LF. (at least for the Prometheus MAXX which has a paper dustcap)
greets & let us know how it turns out
PS.: I reckon you did see their forum:
http://www.audioasylum.com/forums/bastanis/bbs.html
what makes you think it´s the 12CX from Eminence?
Looking at the datasheets and the FR in particular I´d guess it´s more like the Delta12LF. (at least for the Prometheus MAXX which has a paper dustcap)
There´s cap in series with the tweeter, isn´t there?
greets & let us know how it turns out
PS.: I reckon you did see their forum:
http://www.audioasylum.com/forums/bastanis/bbs.html
Thanks, I thought I had read somewhere it was a beta 12 cx but maybe you are right and I'm reading the wrong specs. There is a cap, does that act as a high pass filter or simply +/- db at the tweeter depending on cap value?
Read that too, but still haven´t seen a proof for it.
(as for my assumption likewise)
This might be of interest:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=19883&highlight=
The cap forms a 6dB-highpass filter.
greets
The driver is always referred to as a wideband, I wonder if the delta qualifies for that description. I know it is a customized application but it must start as one of their standard drivers.
Look at the datasheets of the 12CX and Delta12LF.
There is a jump of almost 10dB at ~800Hz in the fr of the CX
whereas the Delta is kinda smooth until 2k.
Then comes a little hump that should be negligible (or easy to tame with a 6dB-high-pass).
If you want to further investigate I could send you an article about the Prometheus MAXX with fr-responses of the fullrangers used (the fr´s look very similar to the Delta12LF here as well) and everything else.
greets
There is a jump of almost 10dB at ~800Hz in the fr of the CX
whereas the Delta is kinda smooth until 2k.
Then comes a little hump that should be negligible (or easy to tame with a 6dB-high-pass).
If you want to further investigate I could send you an article about the Prometheus MAXX with fr-responses of the fullrangers used (the fr´s look very similar to the Delta12LF here as well) and everything else.
greets
Hi Jens, thanks for all the info, one more question, what does the resistor do if it's simply soldered across the woofer terminals?
The 12ohm resistors damp the impedance peak at 45Hz.
Will scan in the graphs later and put them up.
Will scan in the graphs later and put them up.
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