[StevieM]

Hi folks

This is a query about my Aksonics, though I suppose it would apply equally well to any 'speaker. Can the sound quality of my Aksonics be improved by removing the crossovers from the loudspeaker cabinets and siting them separately ? If the crossover components are microphonic then why put them in such a noisy environment in the first place ?

Does anyone have any opinions, facts etc - just wondering really, as it could make a nice little project to undertake now it gets dark early...

Steve

[Jens]

Hi folks

This is a query about my Aksonics, though I suppose it would apply equally well to any 'speaker. Can the sound quality of my Aksonics be improved by removing the crossovers from the loudspeaker cabinets and siting them separately ? If the crossover components are microphonic then why put them in such a noisy environment in the first place ?

Does anyone have any opinions, facts etc - just wondering really, as it could make a nice little project to undertake now it gets dark early...

Steve

Hi Steve,

I had the same thought when I built a set of speakers a few years ago. It is fairly well-known that microphonics may have an adverse effect on sound, although I haven't seen any work that attempts to quantify this effect.

So what I did was to to put the crossover on the outside of the speaker, more specifically on the rear panel. I did not just screw it directly onto the rear panel, though. Instead I mounted the components on a piece of 19 mm MDF. Underneath the MDF I fitted a piece of bituminous felt, under which I fitted another piece of MDF, same overall size as the first one, but only 16 mm thick.

This sandwich was as "dead" as can possibly be imagined. This is because the pieces of MDF do not have the same resonance frequency due to their different thicknesses, and because any slight vibration will be dampened by the bituminous felt

After fitting and wiring all crossover components, using plenty of cable binder strips to hold them securely in place and Sticky Tack/Blue Tack underneath components to dampen any residual vibration, the sandwich was screwed onto the speaker rear panel, using brass screws (a non-ferrous material should be used to avoid interference with coil values). Rubber spacers were used between the sandwich and the rear panel and again between the screw heads and the sandwich to make sure that no vibration got through this way.

By the way, the sandwiching method described above can also be used to dampen loudspeaker enclosures, and it is extremely efficient at dampening resonances.

The sandwich is very easy to make, and if you spray paint the pieces of MDF black and mount the crossover components neatly (you can have wiring underneath the sandwich due to the rubber spacers), the whole thing may even look quite good!  

Cheers,

[StevieM]

Thanks Jens

there's lots of food for thought there. Many years ago (15 ??) I had a pair of Naim IBLs and they had the crossover on the rear panel in a plastic box. What I was thinking of originally was to put the crossovers in an enclosure, to be sited with the amp, cd player etc. I suppose the disadvantage with this would be the possibility of, say, the left hand crossover's magnetic fields contaminating the right hands. Not knowing enough about the subject doesn't help...I should have paid more attention in Physics lessons thirty years ago....
I'll think about moving the crossovers to outside the speakers as you suggest. It would use less plugs and sockets than my original idea, and I have enough offcuts of plywood from making the speakers to be able to make a neat job.
I'd be interested to hear from anyone who has done a 'before and after' trial to tell me if it's worth the effort though !

Steve