I take it you had good results with this method?
I'm a little nervous about accidentally cutting through the main cone while trying to perform the whizzer-ectomy, but I like the simplicity of your method. I will try it one of these days.
Is this to add mass, or to add damping? I'm wondering whether something rubbery like black weatherstrip adhesive ( https://www.canadiantire.ca/en/pdp/permatex-super-weatherstrip-adhesive-59-ml-0383746p.html ) would be a good choice for this?
-Gnobuddy
* no, it does not increase sensitivity, it remains exactly the same at low/mid/high mid frequencies, you lose the treble extension created by the whizzer cone.
Fact is, the voice coil "moves more and faster" than you think, but since cone paper is flexible, and main cone is relatively heavy, voice coil movement is not efficiently coupled to cone, hence not efficiently coupled to air, and you get the typical 24dB/oct rolloff above some frequency between 2500 and 4000Hz typical of Guitar speakers.
But if you add a small and very light extra cone, the whizzer, straight glued to voice coil, not touching main cone, it will catch some of that voice coil movement and couple it to air.
It typically adds one extra octave at least.
Can´t find graphs to link now, but I remember old Goodmans brochures showing frequency response graphs, "Guitar" and "PA" speakers were basically the same up to some 2.5 to 3 kHz.
Guitar speakers had a peak there, and dropped like a brick afterwards; PA ones had less of a peak there, started to drop and then had an "added" broad peak around 8kHz, so extended frequency was reasonably flat from, say, 5 to 10 kHz, "usable" up to 12 kHz or so.
Not bad considering extra cost was less than 50 cents
* you can use small curved "nail scissors" to remove the whizzer, leaving, say, 5% of this behind won´t hurt.
* extra mass around the voice coil will do very very little to main resonance, which might go, say, from 110Hz to 108 or some other minuscule change, but it will tame VC movement a lot.
Just some numbers as example:
a 12" "guitar cone" weighs around 15 grams, so adding, say, 0.5 gram adhesive is almost nothing ... now voice coil itself may weigh 1.5 to 2 grams or so ... extra 0.5 gram there is way more significative.
* a soft adhesive such as silicone will add mass and damping, but I am suggesting "hard" ones such as epoxy or thick nitro lacquer , they will add a small high mids peak.
Bust just try it, we are talking small light cheap speakers, think the cheapest ones fitted to cars, where budget does not allow even for a small cheap tweeter, just a whizzer cone.
By definition those speakers have light thin cones and light voice coils (or they would waste the added whizzer) and work well in small amp duty, think 5 to 15W chipamps.
But again, justy try it, you risk peanuts
Fact is, the voice coil "moves more and faster" than you think, but since cone paper is flexible, and main cone is relatively heavy, voice coil movement is not efficiently coupled to cone, hence not efficiently coupled to air, and you get the typical 24dB/oct rolloff above some frequency between 2500 and 4000Hz typical of Guitar speakers.
But if you add a small and very light extra cone, the whizzer, straight glued to voice coil, not touching main cone, it will catch some of that voice coil movement and couple it to air.
It typically adds one extra octave at least.
Can´t find graphs to link now, but I remember old Goodmans brochures showing frequency response graphs, "Guitar" and "PA" speakers were basically the same up to some 2.5 to 3 kHz.
Guitar speakers had a peak there, and dropped like a brick afterwards; PA ones had less of a peak there, started to drop and then had an "added" broad peak around 8kHz, so extended frequency was reasonably flat from, say, 5 to 10 kHz, "usable" up to 12 kHz or so.
Not bad considering extra cost was less than 50 cents
* you can use small curved "nail scissors" to remove the whizzer, leaving, say, 5% of this behind won´t hurt.
* extra mass around the voice coil will do very very little to main resonance, which might go, say, from 110Hz to 108 or some other minuscule change, but it will tame VC movement a lot.
Just some numbers as example:
a 12" "guitar cone" weighs around 15 grams, so adding, say, 0.5 gram adhesive is almost nothing ... now voice coil itself may weigh 1.5 to 2 grams or so ... extra 0.5 gram there is way more significative.
* a soft adhesive such as silicone will add mass and damping, but I am suggesting "hard" ones such as epoxy or thick nitro lacquer , they will add a small high mids peak.
Bust just try it, we are talking small light cheap speakers, think the cheapest ones fitted to cars, where budget does not allow even for a small cheap tweeter, just a whizzer cone.
By definition those speakers have light thin cones and light voice coils (or they would waste the added whizzer) and work well in small amp duty, think 5 to 15W chipamps.
But again, justy try it, you risk peanuts
This may be the Goodmans brochure to which you refer JM.
Compare the responses of the Audiom 12P-D and 12P-G.
http://www.ajaudio.co.uk/GOODMANS POWER RANGE SPEAKER CATALOGUE.pdf
Compare the responses of the Audiom 12P-D and 12P-G.
http://www.ajaudio.co.uk/GOODMANS POWER RANGE SPEAKER CATALOGUE.pdf
I just spotted this Misco 8" P.A. speaker from a Canadian source, which seems to have most of the right ingredients to work as a guitar speaker. It doesn't even have a whizzer cone to be surgically removed: Misco JC8PA - Free Shipping Across Canada over $150
Note the specs for sensitivity, resonance frequency, even Qts and Qms. And don't forget to notice the price, too!
For those in the USA, I have used this one: GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW . It works okay, is somewhat characterless, and has very little treble extension even with the whizzer cone.
I have also used an older version of this one: 8" Ceiling Speaker with 70V Transformer for Background Music and Paging . This cheap little speaker not only comes with a free 70V audio line transformer (which some have managed to use as an output transformer in a valve guitar amp!), it also comes with a bit wider treble response; bass resonance was around 130 Hz, so guitar is a bit bass-shy. But with a little treble boost in the guitar amp, this speaker actually sounded quite nice for electric guitar.
-Gnobuddy
Note the specs for sensitivity, resonance frequency, even Qts and Qms. And don't forget to notice the price, too!
For those in the USA, I have used this one: GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW . It works okay, is somewhat characterless, and has very little treble extension even with the whizzer cone.
I have also used an older version of this one: 8" Ceiling Speaker with 70V Transformer for Background Music and Paging . This cheap little speaker not only comes with a free 70V audio line transformer (which some have managed to use as an output transformer in a valve guitar amp!), it also comes with a bit wider treble response; bass resonance was around 130 Hz, so guitar is a bit bass-shy. But with a little treble boost in the guitar amp, this speaker actually sounded quite nice for electric guitar.
-Gnobuddy
Yes, that´s it.
Thanks, Galu
PD: you´ll find similar differences in ther brochures.
One which comes to mind is the HH one, comparing some white cast frame black magnet units, one for Guitar, the other for PA use.
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