Series capacitor placement

[presscot]

I’m going to apply a series capacitor tuning technique on my closed-box speakers. There is a confusion on the correct placement when there are examples with different locations.

Firstly, the papers such as Thiele, von Reckling- hausen, and SB Acoustic’s suggest placing the capacitor directly in series with the driver. However, some well-known speaker manufacturers such as Infinity, Wharfedale, etc. placed the capacitor in front of (before) woofer’s low-pass filter, according to the crossover schematics. And, finally, there’s a sense that the capacitor may be able to be installed at the speaker terminals. Thus, which one is the correct position?

 

[AllenB]

The low pass filter is not necessarily effective at these lower frequencies. It normally wouldn't matter even if the order of components does, and sometimes it doesn't. If in doubt, you can simulate.

 

[sesebe]

The series capacitor on woofer is not used for filtering but create a kind o resonance and extend bass response similar with reflex boxes.
But to be effective the value are not arbitrary and need to be updated according cu drivers.