Crossovers in boomboxes

[Line Out]

I just got my Crown CSC-850L and been doing some basics on it. Originally it has only a pair of 2,2uF electrolytic caps for both tweeters. The tweeters are spec'd at 8 ohms (though a multimeter showed 6,8 ohms) so thats a first order highpass around 8800 Hz... So I went ahead and tried a combination that included a 2nd order lowpass for the bass/mids and a 1st order for the tweeters. Both around 3600Hz. Sound is clear and loud, but now there is a hefty peak at somewhere around 2500-4000Hz. Next step is to try a basic 1st order for the woofers but somewhere around 3000Hz. And maybe try above 4000 Hz 1st order for the tweeters.

I used polyester caps and air core coils.

Man this Crown pumps! Brought it to work both yesterday and today and the workshop is a concrete/tile walled. I put the box on the corner and Whoah! Only the sound is a bit creeping so I will need to work on the crossover.

Have anyone of you tried to make your boxes sound better with a little tricks like this?

 

[Superduper]

Tweeters on most boomboxes, due to very small size, are not very strong. Basically, they add a little sparkle and strengthen the highs but most of the sound sprectrum will be reproduced by the woofer, which is really just a full range driver. Using a proper 2-way crossover can inprove the bottom end, making it fuller sounding however there is a risk that the tweeter will not be able to keep up with the woofer when you attenuate or strip the mids and highs from the woofer, and you might have a hole in the audio spectrum, most noticeable especially in the upper midrange area.

As for checking speaker with a multimeter... it is perfectly normal for an 8-ohm speaker to read in the 6's range when measuring with a DMM. The reason is that speakers are rated in impedance, not resistance. Although they are similar, impedance is the "resistance" or "impedance" against an AC current. Your DMM will measure resistance using a DC current source. Also keep in mind that impedance for speakers is usually rated using an AC signal of 400hz. Because impedance actually changes due to frequency (unlike a simple resistor which keeps the same resistance characteristics regardless of frequency), it is a moving target without which a standard measurement point might not be very meaningful.

 

[Line Out]

I know all that but the technicality is a bit hard to put to words because I've spend zero time on English audio forums... this being first

Thanks for clearing things.

I am really annoued about boxes that have plain piezos without proper horns for a "tweeter". There is a few boxes that have real horns, like some Philips models. On those I believe the piezo has to be connected before the low pass filter. If someone wants to try and add one for the woofer.

But the boxes that have cone-type tweeters, are much better target for this kind of crossover "tweaking".

 

[Cpl-Chronic]

I have 2 soundstream 2-way crossovers in my GF-777Z for the outer 2-way woofer/horns & they sound great. No holes or bright spots at all. Hope you get it sorted out.