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Cast or Stamped Frames

Discussion in 'Amps and Cabs [BG]' started by r379, Jun 24, 2005.


  1. r379

    r379

    Jul 28, 2004
    Dallas, Texas
    I'm sure that at some point in time this has been covered on this forum but I don't remember seeing it. Didn't have any luck doing a search but not much good at it either, so...Could you speaker guys out there tell me the pros/cons of speaker construction as it relates to cast and stamped speaker frames? It would seem to me that a cast frame would be stiffer and less prone to flex but is it that important? Thanks in advance.
     
  2. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    How bout you take the speaker that sounds better and fits your needs?
     
  3. r379

    r379

    Jul 28, 2004
    Dallas, Texas
    Doesn't even begin to answer the question I asked.
     
  4. WalterBush

    WalterBush

    Feb 27, 2005
    Yuma, Az
    From what I understand, the cast frames are stiffer, but that basically just means it eliminates one more variable in speaker design, i.e. the sound of the speaker is more dependant on the voice coil, cone, etc, because the frame doesn't vibrate as much. It will allow a good cone to sound good, but a bad cone will still sound bad.


    Having said that, most high-end PA speakers are cast frame.
     
  5. r379

    r379

    Jul 28, 2004
    Dallas, Texas
    I kinda figured it would be something to do with maintaining proper alignment of all the components, but as to how much a properly designed stamped frame would/could flex I haven't a clue.
     
  6. r379

    r379

    Jul 28, 2004
    Dallas, Texas
    Plain Old Me;

    Sorry, that was kinda smart aleck, wasn't it. Please accept my apologies.
     
  7. Tim__x

    Tim__x

    Aug 13, 2002
    Alberta, Canada
    As far as I know...

    Stamped frames only allow shapes that can be formed by stamping sheet metal.

    Cast frames allow almost any 3d shape.

    So cast frames can be made stiffer and can be made to block less of the backwave off of the cone, but they are more expensive.
     
  8. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    Its OK, what I meant was that it doesn't matter what kinda frame unless your making the speaker yourself.
     
  9. syciprider

    syciprider Banned

    May 27, 2005
    Inland Empire
    There shouldn't be a difference. It's the overall quality of the speaker's electrical aspects and cone material that will determine what a speaker will sound like. Mere puffs of wind will not flex a steel basket to the point that it will fail before the speaker itself does.

    But if we must have a pro and con for cast and stamped:

    A casting can be weakened by the presence of voids in the metal.

    A stamping likewise depends on the quality of the sheet metal it was made from.

    So either process can yield a good or bad product but both should be plenty strong for speaker applications.
     
  10. r379

    r379

    Jul 28, 2004
    Dallas, Texas
    My question was asked more out of curiousity than anything else. I don't know that the fact a cabinet was inhabited by stamped frame speakers would keep me from buying it. Avatar boxes seem to do quite well with stamped frame speakers if the experience of other TBers is any indication. I am curious, however, about the opinions/experiences of those on this forum. Any technical info is always appreciated and mostly I was wondering if cast frames are that much stiffer than a well designed stamped frame.
     
  11. Thunderfunk

    Thunderfunk

    Mar 27, 2004
    McHenry, IL
    Cast frames are "always" higher power rated. It has to do with the precision of the component alignment, and I suspect it also affects the heat sinking. If you're putting 500-watts into a speaker, it's 500-watts going into and coming out of the voice coil. That heat has to go somewhere, and it goes into the magnet, which is attached to the frame. Speakers and transformers are a science unto themselves. You don't get an EE degree in transformer design. You have to learn it on your own. Speaker design is all physics. It's all a trade-off. If you want low freqs, you lose efficiency. Or you use a bigger box (upto a point). Higher efficiency? Less lows, or a bigger cone, or more excursion. Take your pick. I think the point being made is you're a bass player. Pick a speaker based on the tone, and power handling which is under the control of the designer. I've done extensive testing of output transformers and have found much voodoo. You can have two identical transformers made by different companies, and they sound totally different. FWIW, Partridge are the best, followed closely by Mercury. In speakers Bergantino has an excellent tone that isn't found in other boxes. You could make an exact copy of his speakers, and I doubt you'd even get close to the some tone. And AccuGrooves have an amazing naturalness to them. It's much more than what you can see in the specs. I think that's the point that "Plain Old Me" was making. Listen and choose. If your question was out of curiosity (duh, you said that), then it's well taken, and I hope I've answered it. :D
     
  12. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    From a non-technical standpoint, I have gigged extensively with both stamped and cast-frame speakers over the years, never had a problem with either. I like the look of cast-frame and believe it to be a little more robust, but constant knocking around by roadies and large equipment trucks in the 80's and early 90's didn't affect either. I would THINK that stamped-frame speakers might be more prone to be bent out of shape by virtue of the weight of the magnet if the cab took a solid drop from an equipment truck or dropped to the floor off of a stage, but I have yet to see (or hear of) such a result.
     
  13. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Cast frames have traditionally been used primarily for two reasons. One is to allow the use of a heavier magnet. Once magnets get large enough they require a more rigid frame than is possible to achieve from stamped steel, otherwise the frame can actually bend under the load of the magnet. The other is precision, which can be better realized from a cast and machined frame than from stamped steel. The tighter manufacturing tolerances possible with cast frames can allow enhanced sensitivity and frequency response.

    A third reason for cast aluminum frames has recently become more important than the others, and that is their value as heat sinks. While this factor was a plus with ceramic magnets, it's a necessity with neodymium magnets, as neodymium will lose its flux if exposed to excessive heat.
     
  14. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Other good features to cast frames are that

    * I don't think you can make a cast frame speaker without actually "bolting" the frame to the front plate of the magnet. A stamped frame unit may be made by a "staking" or a spot-welding method, which may not be as rigid or hold up as well to transport. The material differences preclude welding a cast frame, and staking it would be difficult.

    * The rigidity of cast avoids the chance of any deflection of the frame under the force of accelerating the cone. Not a big effect, but it can steal some energy, or cause subtle resonances. More interest to the hifi folks, but....

    * they are made of non-magnetic material. Therefore there is no possibility of the frame subtracting any field from the gap by shunting any magnetic flux around it. A small effect at most, but depending on the shape, can be measurable. Again more of interest to the hifi folks.....