[johnbomb]

 http://www.audioheritage.org/vbulletin/showthread.php?17513-1st-Order-High-Pass-on-Compression-Driver


Hadn't thought about this before, but I don't like the thought of a DC pulse destroying my compression driver at amp turn on or from inadequate high pass filltering from an active crossover "oopsie" on my part. Since I like to cross these drivers pretty low, usually at around 900 hz, how would you approach capacitor selection such that it wouldn't significantly affect the final acoustic slope after the addition of an active 2nd order LR slope with an F3 of 900 hz?

 

[Bill Fitzmaurice]



Quote:
Originally Posted by johnbomb 

how would you approach capacitor selection such that it wouldn't significantly affect the final acoustic slope after the addition of an active 2nd order LR slope with an F3 of 900 hz?

Use the cap value for a 1st order passive one octave down from your crossover frequency. You should reconsider using a 2nd order HP, which offers minimal protection and maximum phase issues. One of the benefits to active crossover is that you can use much higher slopes and have far less phase issues than practical with passives.

 

[johnbomb]

Thanks, Bill. Looks like a 47uf cap will be close enough, based on the online calculators I found.


John



Edit: That is, for an 8 ohm load.

 

[LTD02]