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speaker surround material

Discussion in 'Amps and Cabs [BG]' started by Fred312b, Jan 17, 2006.


  1. Fred312b

    Fred312b What if I want to play jazz precisely? Supporting Member

    Apr 23, 2002
    Chicago, IL
    i did a search and didn't find what i am looking for, so... does anybody use rubber surrounds in their speakers? i remember from my hi-fi audio days that they are supposed to be more durable/last longer... none of the manufacturer's sites i've been to mention what material they use (just another spec for me to worry about, right? ;) ). as always, any help is appreciated...
     
  2. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    Dunno about in bass cabs, but I have some EAW subwoofers that use rubber surrounds . . . . built like an f-in' tank . . . .

    I think the preferred type of surround is also a function of the cabinet design - ported, reflex, subwoofer, etc. Perhaps Bill F. will jump in here with more of the design issues, and why you may not see that much in bass cabs.

    - Tim
     
  3. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Rubber lasts longer than Foam, which is the other widely used surroud material in Hi-Fi circles. Most Pro-Sound speakers use treated cloth which is the most durable surround material mentioned in this thread so far. It's almost impossible to rip. In fact, most surround damage nowadays is from adhesives letting go rather than the surround tearing. In many cases it can be glued back on quite easily.
     
  4. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    As Pete noted for the most part pro-sound woofers use treated cloth, as it is quite durable. Foam or rubber is used where longer excursion is required, as in hi-fi woofers or pro-sound sub drivers like the Eminence HL10 and Lab 12. Rubber damps the cone, driving the fs down, while foam is lighter and doesn't kill midrange response the way rubber does, so rubber is better in LF drivers, foam better in wide-range drivers. The durability of foam used to be a problem but today's foams are treated to make that less of a concern.
     
  5. Doug Parent

    Doug Parent Supporting Member

    May 31, 2004
    San Diego, Ca.
    Dealer Nordstrand Pickups.
    Bill, I was under the impression that rubber surrounds were almost entirely in the home hi-fi realm. I guess I had the idea that rubber made the cone "looser" or better able to go lower, but sacrificing efficiency.

    Is this true or what are the other key factors that determine efficiency?
     
  6. Fred312b

    Fred312b What if I want to play jazz precisely? Supporting Member

    Apr 23, 2002
    Chicago, IL
    huh- this actually makes sense, since my swr cabs had surrounds that were neither rubber or foam... thanks guys for putting my spec-obsessed mind at ease :bassist:
     
  7. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Using rubber or foam is mostly a matter of excursion, and since pro-sound woofers don't have that much they don't use it. Pro-sound sub-woofers like the Eminence HL10 or LAB 12 do have high excursion capabilities, and they use foam. The surround doesn't affect overall sensitivity all that much, but it does affect driver fs, and therefore also high-frequency extension, another reason cloth is preferred for extended range pro-sound woofers.
     
  8. Doug Parent

    Doug Parent Supporting Member

    May 31, 2004
    San Diego, Ca.
    Dealer Nordstrand Pickups.
    :) thanks!
     
  9. etnops

    etnops

    Nov 6, 2005
    great question.

    the reason why you don't see rubber surrounds for MI speakers, or Pro Audio drivers in general?

    MASS!

    they simply weigh too much. musical instrument and pro audio drivers are about 1 thing: efficiency. and since efficiency is a product of BL (motor strength) and Mmd (moving mass), cutting mere grams off, will net you greater electrical to acoustical transfer.
    typically, a cloth surround treated with phenolic (a rubberized solvent material to provide damping and as a sealant of the cloth) weighs about 1/8 of what a typical rubber surround of the same diameter would weigh.
    it's not so much about excursion potential from a specific material....i've made cloth surrounds capable of 3" P-P travel....it's about realizing your goals and understanding the compromises involved, and choosing the right materials for the job.

    just for kicks, i just tooled up a new high excursion TPE (santoprene) surround for a long stroke speaker (12"). half surround mass = 58g. compare that with a conventional 12" MI speaker, where the entire Mmd is less than that!

    hope this helps some.


    -SDP
     
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The end result of which is:
    and it's in the higher frequencies where pro-sound woofers excel in sensitivity; below 60Hz on average they're no better than hi-fi woofers. The loss of sensitivity that foam or rubber surrounds create in the higher frequencies are of no concern in pro-sound sub drivers, where response above 500Hz is moot to say the least.
     
  11. etnops

    etnops

    Nov 6, 2005
    Yes and No. Mass has nothing to do with HF extension. HF limits are dominated by Le (inductance). The other part of the HF equation is cone diameter and material (breakup, etc).

    Now, obviously, if you had a speaker with 500g of mass and low Le, it wouldn't extend very high, because the insane amount of mass would offset the sensitivity of the low end to the high end.....but that's an extreme case.
     
  12. fatsobasso

    fatsobasso

    Dec 24, 2005
    Ormond florida
    where can one get the phenolic rubberizing solvent?
     
  13. etnops

    etnops

    Nov 6, 2005
    adhesive companies who cater to the loudspeaker industry usually carry a form of it. C.P. Moyen, Cyberbond, Ellsworth Adhesives......but they all have a minimum order policy (usually $200 or more) and the stuff comes in bulk. i have to buy mine as a powder (mix w/water) in 5lb batches.

    any particular reason you need the stuff?
     
  14. fatsobasso

    fatsobasso

    Dec 24, 2005
    Ormond florida
    Well a small area on one of my speakers, has some of its coating scratched off on the surround,so i figured if it was easy enough i could just touch it up,any ideas?
     
  15. etnops

    etnops

    Nov 6, 2005
    I wouldn't worry about it, to be honest....but that's just me. :)

    for a quick fix, either a dab of rtv silicone will work, or my preference....good ole' elmer's glue. thin it out with some water, and lightly brush it on with your finger. let it try a couple of hours and you should be good to go.
     
  16. fatsobasso

    fatsobasso

    Dec 24, 2005
    Ormond florida
    that sounds cool.thanks