Adding mass to a driver

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#61
I thought he said he had a very good midwoofer
and he made it into a fairly good woofer
but that its no longer good for anything other than low bas
well...whatever
he is happy, so it doesn't matter no more, really

but many pro woofers have fairly heavy cones
the cone weight daudio25 ended up with is not unusual
but these days they will also have double spider

my main problem is...does it have enough Xmax
 
#62
Yes,my 15" was good pro midbass with not so much low end. Now, with added mass it is good subwoofer but not midwoofer anymore...Xmax is only 5mm,but for my little apartment and taste it's more than adequate.
I believe that 10" Beyma 10G40 can be a better midbass than any 15" in 70-300hz area.For home use.
I also believe that big diameter,heavy,low fs sub + Beyma 10g40 both at 30-300hz can be better than any 15" alone.

I could go for other subwoofer,maybe one from car audio.But i had those pro 15" ,made an experiment and it was successefull from my point of view.
 
#64
ups! ... my dustcap just fell off :clown: 😀
 

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#65
Just joining this conversation, but I hope this helps. I have done this so I know it works. You can coat the back side of the speaker cone with glue to add mass and stiffness(I used wood glue). This will effectively lower the Fs and stiffen the cone. I had to do this to a pair dof 18" Black Widows 20 years ago in a P.A. system for a band I was running sound for. It can make the woofer a little slower, but it's not a terribly noticeable issue unless you use a whole bottle of glue. For the specific situation I had, the woofers souned like they were slapping on a hard kick drum note. The glue fixed the problem immediately, and smoothed the overall response of that particular system. The good thing is that this will not leave a projectile on the dirver. It adheres to the back of the cone and you can't see it when the driver is loaded in a cabinet.
 
#68
peeled off the rest of the 'faked' coating
and still in good condition 🙂

makes me wonder ... the surround appears to be glued on to this fake paper coating, which I peeled off so easily :scratch2:
 

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#71
jplesset said:
I remember 'way back when I worked for Infinity, building 1001 model speakers, we used a product called, "perma gum" to add mass to our 12" woofers. Pressed it in at the junction between dust cap and cone. Stuck well, and seemed to be permanent. Back then, we didn't measure stuff (early 1960s), but did it all by ear....
Click to expand...

I recently acquired a pr of Infinty 1001A for AUD$15 and refoamed them. The 'added mass' of the black goo is very apparent. The boxes are stuffed with absorbent fibre which provides extreme damping presumably to control the heavy cone's resonance. They sound great! (Duplicating the 1960's philosophy, no stuff was measured!)😉
 
#72
Yep, 1001s were what I started out building at Infinity. If the woofers had foam surrounds, they were "Becker". CTS were what we mostly had, and those had cloth surrounds. Retail was $149 each, US, if I remember correctly.

Measure? Hah. Yes, we did kind of measure. Outside. After Arnie's golden ear had already gotten the sound to where he liked it...

The "permagum" we applied was gray back then. I suspect somebody has replaced your drivers since...
 
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