In Reply to: Re: Got it! posted by Adrian Mack on February 24, 2003 at 01:46:06:
Hey again! The schematics you sent me are GREAT! Just what I was looking for. Just have a couple of quick questions....Since compression drivers are high efficiency (although it should be lowered with HF compensation circuit I think), can I still install a simple attenuation circuit (if I find I need one) like the one here at the compression drivers terminals http://www.loudspeakers101.com/Lpad.htm
How should I decide how many db of HF attenuation to use in the circuit? I know it involves looking at the graph of the response of the compression driver on the horn, then summing the compensation circuit with it to get final response. So I think what I do is see how many db down at 20KHz it is, then pick the db attenuation values in the chart you sent me by email?
On the very last page of the file, it says "Note: Components R3, C4 and C5 are not used with woofers listed on this page. In all other respects, the 800aLxxdB crossover is the same as the standard 800a0xxdB 800Hz crossover, and the 1K6aLxxdB crossover is the same as the standard 1K6a0xxdB 1600Hz crossover." And the woofers listed are the JBL 2205H, 2226H and 2227H. Why are these components left out of the design with these woofers? I think though the file said this is only when using it as a pseudo first order filter. By the way, whats the difference between a pseudo first order and normal first order filters?
On the schematic, where it shows the symbol of the woofer, right behind it is the symbol for an inductor (the curely line) but no marking for it like L4 etc. I believe though that it is just part of the speaker symbol (because speakers themselves are kind of like inductors?).
Thanks! Adrian
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