Celestion Ditton 66 crossover original green film caps - keep or replace?

[witwald]

The simulations of the filter response functions indicate that:

• the woofer has a 24dB/octave 4th-order lowpass filter
• the tweeter has a 24dB/octave 4th-order highpass filter
• the midrange has a bandpass filter with 12dB/octave 2nd-order slopes

The filter design appears to be a little unusual, in that the slopes of the woofer/midrange crossover and midrange/tweeter crossover are not trying to be complementary. It's probably a good choice by Celestion's loudspeaker designer(s), as the woofer's high-frequency response is quickly rolled off, which helps blend its dispersion characteristics to those of the 57mm midrange driver. The tweeter has its low-frequency response rolled off very quickly, which would help with power handling, and may also benefit a smooth transition of the off-axis response when handing over from the midrange to the tweeter.

From the Ditton 66 loudspeaker's published response curve (see below), the crossover design seems to produce a reasonably good result.

 

[cb1]

Thanks for the information and the revelations!
I rather like the idea of the midrange having some boost as it’s the range from which I usually want to hear more activity. When I listen to a step tone test (the one I’ve used is a section within

) I find that from around 300Hz up to about 1Khz I perceive the tones as louder.
A couple of louder peaks also seem (again, subjectively) to occur at approximately 1.2 and 2khz.
Not too worried if the bass section has, comparitively, less signal as these speakers have an abundance of bass ability and anything that might help to modestly kerb 'boom' in the listening room is fine in my situation.
Thanks again for doing the homework.

 

[witwald]

Looking at Celestion's published frequency response curve for the Ditton 66 loudspeakers, it seems to me that there are two shelves in the response. In the picture below, the first one is indicated by the red line, and the second one by the green line. I set the level of the red line by considering the SPL between 100Hz and 1kHz, while the level of the green line was set by considering the SPL in the 1kHz to 10kHz range. It would seem that the Ditton 66 has about 2.5dB more output between 100Hz and 1kHz than it does between 1kHz and 10kHz. This seems to tally with your observation that these loudspaekers have an abundance of bass ability.