Home Speaker Asylum

General speaker questions for audio and home theater.

RE: Sonus Faber replacement woofer


I know how it feels when you blow up an oldie but a goodie...

****WHATEVER YOU DO HERE... make sure you check your amp for DC output. Although many amps have DC protection (or are tube amps with output transformers, which cannot pass DC) some amps do not. If the coils burned up due to output transistors failing and putting bus voltage to the drivers, the NEXT speakers will burn up just as fast as the first ones.

With a DC Voltmeter or "multimeter" set to DCV, check for DC output on the amplifier speaker terminals. If it's millivolts or less you're okay. If it reads in the tens of volts, you have a bad amp.****

So back to the "find the old driver game".

I checked the Tymphany / Vifa archives.


Turned up nada. I have a hardcopy Vifa catalogue in my "box of old catalogues" at home - I will check if that model is in there. But I think the "MW-" (midwoofer) driver predates even the mid 80's catalogue I have at home. If it's not even in the archives, it's probably late seventies early 80's vintage - which is getting pretty old these days. (30+ years! if you can believe that!!).

If you're lucky, there is a modern variant that simply has a different name. If I can find the "MW-" driver in a catalogue, I can compare it's specs to modern 17cm variants and see if it matches. It's unlikely but possible.

Watch out for recommendations of "it will fit in that hole" and "the frequency response graphs look kinda close". Voice coil inductance, inductance rise, and certain T/S parameters are also critical to matching what the crossover is doing inside that speaker. Impedance curves are elusive while newbies tend to focus only on frequency response. With passive crossovers, impedance (interacting with crossover reactive components) DETERMINES frequency response! There is way to do crossover mods to integrate a new driver, but this can be a whole new crossover and takes a special skill set to do. And you have to have a love for DIY, or "pain" as some put it.

In any case, if you go with the "fill the hole" method you will likely end up with new voicing (at best) or worse a botched up tonal balance.

Another possible option is reconing. Those are nice looking speakers with what seems like well built cabinets. If they sound great and you are partial to them, a re-cone might be an option.

I will check old catalogues and get back to you.


Edits: 03/14/12

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