Singular as subwoofer: low pass filter design (Singular)
The project is to use a dedicated Tripath based amp for a Singular with Fostex FW208N woofer. The singular will be used as subwoofer in the range of 35hz~200hz.
The idea is to modify the low pass filter present at the output of the Tripath amp to get a frequency cut at 200hz.
The low pass filter in the T-amp is a second order 107kHz LC filter with a L=10uH and C=0.22uF. The T-amp has too a Zobel RC filter with R=6.2ohm/2W and
C=0.22uF.
Using some calculators on line I got a 2nd order 200hz LC filter with L=9mH and C=70uF. I couldn't calculate the Zobel filter because there is not the "Le" (bobbin inductance?) in Fostex datasheet.
I've to confess I don't understand much about filters, can you help?
P.S.
T-amps work better with copper foil coils used in Xovers.
Singular as subwoofer: low pass filter design
Hi Giovanni,
I've to confess I don't understand much about filters, can you help?
Why don't you create that filter in front of the T-amp? This way the amp is not bothered with the impedance behaviour of the driver, any filter likes to see a flat impedance to work optimally...
Ciao,
Bert
--
BD-Design - Only the Best!
Singular as subwoofer: low pass filter design
"In front" means before the amp? (anyway the t-amp would need the LP filter to recover audio from the switching signal).
Any circuit for a suitable filter for this driver?
Here is a link to give you an idea...
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
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BD-Design - Only the Best!
Here is a link to give you an idea...
Thanks for the link.
But I've no fun if I don't try new things.
For a line level LP filter I have another option: I have two DACs and an EMU1212M inside the PC, with a huge DSP and 2 separate digital outputs. So I could do filtering inside the PC and send different digitally filtered signals to the 2 dacs.
The problem is that I have still to learn how to syncronize the two dacs to a common clock.
The other option to use the amp output filter as LPF is funny because there are no components to add, only to mod. I think nobody tried this, that's why it is attractive
Knock yourself out...
Hi Giovanni,
The other option to use the amp output filter as LPF is funny because
there are no components to add, only to mod. I think nobody tried this,
that's why it is attractive
Then you have to play around with that and try to have the Fostex driver's impedance flat from about 1 octave below the crossover frequency and up...
This way the filter works as it should but still, you might want to cross sooner to EQ a rising response if present.
Enjoy!
Bert
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BD-Design - Only the Best!