PDA

View Full Version : modifying L36 crossover to change frequencies



kneedeepinit
11-17-2015, 08:35 AM
I have a pair of speakers that are using an L36 crossover network. I am very happy with the sound but am curious about a change. The woofer to mid crossover frequency is 1500 Hz and I would like to drop this to 800-1,000.

Is it possible to change out some of the components to accomplish this? The purpose of this is to see if the speaker works better before committing to an expensive build.

grumpy
11-17-2015, 10:33 AM
to first order (so to speak), you could double the inductor 2mH and capacitor 6uF to cut the LF/MF crossover frequency in half (to 750Hz)...
but that assumes several things (which is why a good crossover design is more than just a single equation):

1) that the impedance of the driver is flat (and it is not) or at least the same value at the new crossover point (it is very unlikely).
2) that the driver response is relatively flat in the frequency range that the crossover is being moved (possible).
3) that the driver response (natural rolloff) wasn't used as an effective element in the crossover (also possible).
4) that the MF driver can handle the extra LF load (6dB/oct doesn't reduce the LF energy reaching the MF driver very quickly
as frequency gets lower ... if you don't play loudly, this might be ok).
...

But having said all that, it's easy to ignore all of that and try, if you don't mind pulling the 2mH inductor and 6uF cap from one of your L36s
(put the 2mH in series with the original, and put the 6uF in parallel with the original).

kneedeepinit
11-17-2015, 12:20 PM
to first order (so to speak), you could double the inductor 2mH and capacitor 6uF to cut the LF/MF crossover frequency in half (to 750Hz)...
but that assumes several things (which is why a good crossover design is more than just a single equation):

1) that the impedance of the driver is flat (and it is not) or at least the same value at the new crossover point (it is very unlikely).
2) that the driver response is relatively flat in the frequency range that the crossover is being moved (possible).
3) that the driver response (natural rolloff) wasn't used as an effective element in the crossover (also possible).
4) that the MF driver can handle the extra LF load (6dB/oct doesn't reduce the LF energy reaching the MF driver very quickly
as frequency gets lower ... if you don't play loudly, this might be ok).
...

But having said all that, it's easy to ignore all of that and try, if you don't mind pulling the 2mH inductor and 6uF cap from one of your L36s
(put the 2mH in series with the original, and put the 6uF in parallel with the original).

thanks Grumpy. I think this will give me enough information to see if an entirely new crossover is warranted

jlyons
11-27-2015, 10:09 PM
Grumpy is right, and if the system you are crossing uses the L36 transducers, then you might consult the L50 consumer sheet network diagram. The L50 and L50A use similar drivers to the L36 but at lower crossover points.

grumpy
11-28-2015, 08:15 PM
Well, as helpful as our intentions were, let's just say the driver complement in use was ...unexpected.

Probably best to just let this thread die in peace.