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Speaker Size and Wattage

Discussion in 'Amps and Cabs [BG]' started by mdsmith, Dec 17, 2008.


  1. mdsmith

    mdsmith

    Jan 31, 2008
    Hey guys. Sorry to keep asking so many questions, but looking at all the avaliable amps is a little overwhelming. I was hoping someone could explain the relationship between speaker size and wattage. I have a combo that's 20 watts and has a 12"speaker, but I see a mark bass amp that has 1 12" speaker and 300 watts. I would think that you would need a lot bigger of a speaker with that much more wattage(but then again, I don't know much). So, which is responsible for the volume and which for the sound(i.e mellow or punchy), and which is more important in a amp that will only be used at very small jams?
     
  2. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Neither speaker size nor wattage have anything inherently to do with volume or tone. All diameters of speaker may be implemented with a very wide range of tones and power handling ability; and wattage may be used in countless ways with varying degrees of efficiency or "loudness".

    Neither is more important at small jams. IMO however (and this is subjective) I would choose a physically large speaker cab for best bass tone, with perhaps 2x10 or 1x12 or 1x15 cones. Again, the size of the box means more to me than the diameter of the speakers. Then for wattage you really only need like 100W, as long as you don't crank the lows and scoop the mids. Low frequencies eat up all your wattage. For small jams I would even turn down the lows in order to allow more power and clarity in the mids.
     
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Neither. Driver size and power handling are only casually related, as are driver size and output and tone. The only definitive thing you can say about a 20 watt twelve is that it's a lot less expensive than a 300 watt twelve, which is why no one puts 300 watt drivers in 20 watt combos.
     
  4. mdsmith

    mdsmith

    Jan 31, 2008
    O.k> I think I'm following you guys. So, what is the difference between a 2x10" and a 15" (assumng they are the same wattage). I mean, what difference will you hear?
     
  5. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Insufficent data. The size and wattage alone mean very little. No less than a dozen other factors are more significant, not the least of which is the cabinet the drivers are loaded into.
     
  6. mdsmith

    mdsmith

    Jan 31, 2008
    Gotcha. I was under the misconception that the 2 10s would give you a tighter sound while the 15 would be rumblier(if that's a word). So there's really no rule of thumb as to what would give me a warmer. mellower tone as far as size and wattage. I know I need to try different amps out to see what I like, but I was kind of hoping for a starting point to give me an idea of what to look for to achieve a paticular sound. Thanks
     
  7. RickenBoogie

    RickenBoogie

    Jul 22, 2007
    Dallas, TX
    Your best bet is to try out several different amps, and speakers, or combo's, and let your ears decide what sounds best. As a starting point, look at 100 watt 1x15 combo's, and notice the different tones between various makes and models.
     
  8. mdsmith

    mdsmith

    Jan 31, 2008
    Cool, thanks
     
  9. heavyhitter

    heavyhitter

    Jan 24, 2008
    There are too many factors to figure in comparing 2 10's to a 15" but lets say all factors are equal the 10's should be faster and punchier with the potential of more SPL and the 15 would be slower and able to go deeper. That said a even a quality 8" in a proper enclosure can out perform a subpar 15" in a crappy enclosure.

    Sound is nothing but sound waves. The way to make volume is to move more air. 2 10's have more displacement than a 15" so with every thing equal the 2 10's should be louder. But rarely are things always equal and if the 15" had a greater excursion it would perform more SPL than the 2 10's.

    In a nutshell a higher quality speaker will outperform a lower quality speaker. Keep in mind that quality is not always equal to the dollar amount either.

    SPL and Xmax rating can give you an idea how a speaker will perform volume wise. How ever SPL and sound quality do not always go hand in hand.
     
  10. And I wish I had the opportunity to try out a Phil Jones cab full of 5" drivers...
     
  11. Arx

    Arx

    Jan 22, 2008
    That's not necessarily a misconception.

    That's commonly the case. An average 10 will tend to have a lot more midrange, which will give the impression of punch, as compared to an average 15, which will tend to have a stronger fundamental, and less upper frequencies.

    Keep in mind, though, that this is a huge generalization and that there's MANY exceptions.

    It is rare that you'll get a smaller speaker with a really strong fundamental, though the fundamental isn't nearly as important as you might think. Many cabs rated down to 60Hz or so still sound really "deep"

    -Nick
     
  12. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    All driver cones move at the same speed, which is precisely that of the applied signal in Hz. If it was not so you'd play one note and a different note would be heard.:crying:
    For this reason the terms 'fast' and 'slow' are meaningless with respect to loudspeakers. Transient response is what most people are referring to when they use these terms, but transient response is not particularly related to cone size.
    The only factor that's purely attributable to cone size is the angle of dispersion.
     
  13. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    DeltaliteII 2510 surface area of cone (Sd): 350.1 * 2 = 700.2 square centimeters
    DeltaliteII 2515 surface area of cone (Sd): 856.3 square centimeters

    The term displacement might better refer to Vd, which is Sd times xmax.
     
  14. 2x4strgkramers

    2x4strgkramers

    Dec 15, 2008
    Do not overlook sensitivity when selecting cabs. The lower the DB rating on this is the more power the cabs consumes to produce a given SPL.
     
  15. 2x4strgkramers

    2x4strgkramers

    Dec 15, 2008
    Well define response. You will have substantially more flex in a larger cone given that the speakers materials are all relatively the same also as wieght goes up tonal accuracy can go down if the speaker does not have enough motor behind it.

    So you can make a dozens different cases for all sorts of scenarios and be correct on all sides.

     
  16. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    The teeny tiny speakers in headphones are great. I can listen to the second song on the mp3 player before the first one has even finished playing. Unfortunately everything is pitch-shifted upwards but it's a small price to pay for speed.
     
  17. kraigo

    kraigo

    Jun 21, 2007
    Minneapolis, MN
    Are you sure you don't mean square centimeters? Area, not volume.

    KO
     
  18. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Indeed, kraigo it should have been cm². Figuring out a cab volume at the same time ; }

    Fixed.
     
  19. heavyhitter

    heavyhitter

    Jan 24, 2008

    I see the values that are given on the Eminence website but Im still having a hard time beliveing the number unless the 10's are shallow and the 15's are really deep.

    Even fast simple math would show that 10x(pi)^2 x2 is greater than 15(pi)^2

    however cone surface area = (pi)rs + (pi)^2

    Im no math nerd but Im failing to see how a 15 can be more than 2x10.
     
  20. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Don't believe Em's datasheets then. But I can assure you lots of other driver brands have similar figures ; }

    Besides cone depth you also need to consider that the cone is not either 10" or 15" and that those are rounded-off frame sizes and that the cone diameter is smaller than the frame/surround.