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Bigger speakers=louder sound: true or false?

Discussion in 'Amps and Cabs [BG]' started by Rockin John, Aug 1, 2001.

  1. It has been suggested to me that (say) a 4x15 cab will be louder than a 4x10 cab, all other things being equal.

    The reasoning behind this is that the 4x15 will be moving more air than the 4x10 by virtue of the greater surface area to move that air.

    Opinions please, guys.


  2. mikemulcahy


    Jun 13, 2000
    The Abyss
    I dont really think there would be a linear comparison due to the fact that there are so many variables to consider. Power for instance, 400w may sound fine in a 410 cab, but most likely will not be enough to push 4 15's. IMO, making allowances for the different power needs,say 400w to the 410 and 800w to the 415, in most cases the 415 would be louder. But then again there are many variables to consider.

    But thats my uninformed opinion and most likely I am wrong.

  3. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    Read this thread:

    2x 10 vs. 4x10, loudness

    In short, yes. All other things being equal. More speakers = more volume. This does not mean better tone, just raw volume.
  4. Un-amplified speakers are rated by their efficiency. It is usually writen in the specs.

    For ex. It is writen:

    98 dB @ 1 watt, 1 meter.

    Meaning, the manufacturer put 1 mic infront of the speaker, at 1 meter away; an input(pinknoisecontain equal sound energy per octave) of 1 watt will produce 98 db.

    So how loud a speaker has nothing to do with it's size. Infact if you use a 15" speaker, it is obviously "heavier" to push than a 10" speaker. So what you said was half true and half wrong.

    It's true that 15" push more air compared to the 10", and therefore, for the same reason, you need a stronger amp to push the 15" speaker.

    The bigger the speaker's circumference, the lower in freq it gets(generally speaking). It has more to do with Freq response then how loud it gets.

    If your speaker has a horn built in, that also affects it's "loudness". Because horn is way more efficient than speakers. Meaning it's easier to produce a lounder sound than speaker.....louder doesn't necessarily means lower.

    Hope that helps
  5. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    This is not really true. I have recently replaced my Cyclops (2x8+horn, 1x15) with the RC21018 (2x10+horn, 1x18). Both of the rigs are rated at 600 watts. I use the exact same settings and the new rig is noticeably louder.

    I know that the sensitivity of the speakers, size of the cabinets, and man other things effect the over all picture.

    But in this thread the question is, with all things the same do more speakers produce more volume. (IME and what the technical people here say is) Yes, more speakers will produce more volume.
  6. Gabu:

    You might be replacing it with a better quality speakers I think. Not too sure of your setup of course, but that might be the reason.
  7. mikemulcahy


    Jun 13, 2000
    The Abyss
    I dont think I can agree with that one Oh Gabby one. I dont think that at the same wattage, the two cabs will produce the same "loudness". The larger the speaker the more power required operate it, otherwise we could use a whole lot less power (I would love that). Maybe one of our beloved electronic gurus can enlighten us. I know I could use it.

  8. MikeyD


    Sep 9, 2000
    Hmmm. I'll try to be kind. This is a complex subject when you get into the real acoustics of what's going on. I (and others) have done a lot of posting on this subject (i.e., see Gabu's post above!). I really mean it when I say *complex*. If you really want to understand this phenomenon, you have to study acoustics, and generally this requires a lot of advanced college math and physics. Those who don't have such background have to be careful and a little reserved about offering opinions. I majored in acoustics and EE in college, and I'm even a bit gun-shy in some of these areas (because I'm currently not working in the field as my primary focus). When you get to this level, it defies simple "rule-of-thumb" generalizations, believe me... because it's simply not simple! That said, I am not trying to discourage anyone from the topic. All I'm saying is it takes a lot of learning and knowledge to really understand it. I hope that some of the good recent and archived posts in TB can shed light on the subject.
    - Mike
  9. MikeyD


    Sep 9, 2000
    Mike, this isn't true. If a large speaker/cab has the same sensitivity rating as a smaller one, it does not care how much power you feed it. Case in point: I was doing a measurement on my Carvin 1x18 the other day for a post for bgavin. I measured about 1.5 volts across a 100-ohm series current-sensing resistor. This means 15 mA was flowing into the speaker. At a nominal impedance of 4 ohms (which is probably close at the low frequencies I was feeding it), P = I^2*R = 0.0009 watts!! Yet I could *clearly* hear the notes coming out of it. Why? 0.0009 watts is 30.5 dB below 1 watt. If the speaker is rated for, say, 95 dB at 1 watt, then it is producing about 65 dB at that wattage level. If I had plugged in a smaller speaker of the same sensitivity and fed the same wattage, it would be equally as loud.
    - Mike
  10. As far as i know.. bigger speaker surface = more air movement = more sound....

    big speaker ( 15" / 18" ) = more bass, but tends to go sloppy.

    medium speaker ( 12" / 10" ) = nice bass, tight sound

    small speaker ( 8" ) = tighter sound, less bass
  11. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    What I am saying, is from experience. I can audibly tell that one rig is louder than another. Now, I don't know acoustics or electronics. But I know what I hear. :)

    I looked on Carvins website but was unable to get info on the speakers from the RC210, or Cyclops product info pages. So I looked in Speaker components. I am pretty sure that these would be the speakers used.

    The 18" Speaker:

    Our largest, and the best 18" cast frame woofer in the industry with a massive 4" voice coil for improved high power performance for bass guitar / pro sound applications.
    Power: 800 watts.
    Freq. Response: 30-2.5k, 4 ohms.
    18 lb. magnet structure.

    The 15" Speaker:

    Our heaviest 15'' woofer features improved high power performance for bass guitar / pro sound applications.
    Power: 600 watts.
    Freq. Response: 38-3k, 4 ohms.
    13 lb. magnet structure.

    The 10" Speaker:

    10'' speaker is ideal for bass guitar or sound reinforcement.
    Power: 200 watts.
    Freq. Response: 60-5k, 8 ohms.
    5 lb. magnet structure.

    The 8" Speaker:

    8'' speaker is designed for sound reinforcement. Currently used in our 3-way loudspeaker enclosures and our Cyclops Bass Combo.
    Power: 200 watts.
    Freq. Resonse: 60-9k, 16 ohms.
    4.5 lb. magnet structure.

    They do not list their SPLs unfortunately. I can't check right now, but some of these speakers might be on BGavins lists. Assuming that the SPLs are similar, the amps were played in the same location under the same operating condition. One rig was louder than the other.

    It would seem to follow that the speaker area would have something to do with it. :D
  12. EString


    Nov 20, 2000
    Los Altos, CA
    If all the speakers are all the same size and type and you just have more speakers, then that should be louder. However, when you are dealing with different speaker sizes, things get more complicated. While a 4x15 might be louder than a 4x10 with comparable speakers and build on PAPER, in the REAL WORLD things are more complicated. Loudness to the human ear also relies on the specific frequencies being projected. A very powerful 20" speaker might not sound as loud to you or me as a mid powered 6" speaker because the human ear tends to focus more on the midrange, rather than extreme highs or lows. Similarly, the Seymour Duncan/Basslines SPB-3 Quarter Pounder for P Bass pickup has more output than the Seymour Duncan/Basslines SPB-2 Hot for P Bass pickup, but the Hot might sound a tiny bit louder because its midrange is more emphasized.
    So while a 4x15 might be louder on paper than a 4x10, the real world gain might be marginal.
  13. mikemulcahy


    Jun 13, 2000
    The Abyss
    <---- takes a bite of humble pie and stands corrected and a little more educated.

  14. I'm gonna jump in the boat and try to simplify this, cause it is not that complex...believe me. I'll try.


    If you have 4 AA Batteries, and you take 1 small light bulb, obviously the light bulb will light! And if you take 5 more light bulb without adding the batteries, and connect them with the same 4 AA batteries, would the light bulb light? Sure, but not as bright, right? It is obvious that the overall capability of all those light bulb is greater in brightness if compared to only 1 bulb. If you add a larger bulb for example, you'll need to add more batteries to really see it's max brightness. With only 4 AA batteries, it'll light, but not to it's max brightness.

    Therefore, all of those theory that has been presented on this thread or the one before are all true, but not in the common ground.

    The topic question itself is a bit misleading. Well, because you cannot even talk about how loud a speaker would go without covering many aspects....amp, it's efficiency, and etc.

    First of all, people seems to mistaken the idea that speaker that lot's of us are talking are not combo speakers that has an amp built in. So you have to remember that the speaker by itself is very dependent to whatever is giving them the power.

    Now, if you consider this. Horns are technically a very small speaker driver right? Really-really small! But in comparison to regular speaker driver, they are louder abviously. Why ? Many logical reasons and technical too.....they way the horn has been design, it saves it's energy by not having the need to produce any LOW freq that is the main culprit for speakers to require such a huge amount of power.

    So there are no quick answer...everything is interrelated wether you want it or not. There are no "true or false" answer to this.

    If Rocking Johnson says this:

    "It has been suggested to me that (say) a 4x15 cab will be louder than a 4x10 cab, all other things being equal.

    The question I have to him is, would that mean the 4x15 has another set of similar amp, and being compared to the 4x10 side by side etc etc? Or was it done by removing the 4x10 cabinet and pluging in the 4x15?

    ALSO, if the original amps capabilty exceeds the 4x10 capabilities, (in other words incompatible) then when you switch to 4x15 with exactly the same amp etc, obviously the 4x15 is gonna be louder.

    SO please list all the specs(your amp, both the 4x15 or 4x10 cabinet if you really want to know the answer) Cause this kind of question usually lead to nasty arguments. Simply because the question is not clear, and people answering them simply take the liberty of assuming this and that. And during arguments, both party are talking 2 seperate things.
  15. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    Sorry for quoting myself, but this is an addon to what I said previously.

    I have checked BGavins file on Carvin Speakers.

    The 10" speakers are 95db to the 8" speakers 94db.

    The 18" speaker is 98db to the 15" speakers 97db.

    Now I bet (in my assertion that the new rig sounds louder) that the speakers that primarily come to play are the 10s and 8s, because the 15 and 18 are used as my subwoofer and play the sounds that are more felt than heard.

    So the 10s are 1db more sensitive. Now with the power feeding into them roughly the same, it would seem to follow that they would be somewhat louder based on that alone.

    This means in my "test" all things were not equal. Since this was done by ear I do not know if what I heard was just that 1db or if it was a 2db difference for example, 1db for the sensitivity and 1db for the extra speaker area.

  16. Max SPL Output = (10 x log MaxInputWatts) + SPL DB at 1w/1m

    Using the Ampeg PR-810H it computes as:

    Given: 100 SPL at 1w/1m
    Max SPL = 10 x 3.0791812460476248277225056927041 + 100 = 130.79

    The above will tell you that maximum SPL your rig or speaker can produce at maximum input power. Maximum loudness depends directly upon both the efficiency of the drivers and the amount of air they can move, and not solely on their physical size.

    The Cerwin-Vega Stroker 18-S moves the largest amount of air volume I've catalogged so far. It is middle of the road regarding its efficiency, and will produce a healthy 128 max SPL at 1600 watts input. It has LOUSY low bass response.

    The Rockford RFR-3115 moves 75% as much air, still MUCH more than the average bass driver, but it has terrible efficiency at 0.25% compared to 2.41% for the CV. The Rockford produces 121 max SPL (a -7 dB drop), but has excellent low bass response (it is a subwoofer).

    The Eminence Kappa 15" series is the loudest I've catalogged at 129 SPL, and they do it with only 400 watts input power. However both series require nearly 6 cubic foot cabinets, and neither has excellent bass response below 50 Hz.

    In the bass world, you have to specify WHERE on the scale you want to be loud. It is much harder to be loud down very Low.
  17. MikeyD


    Sep 9, 2000
    It's a good thing everyone posting here has a doctorate in electroacoustics from Penn State, or else a casual reader might be confused. ;)
    - Mike
  18. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    :D Yeah... It's enough to make me go back to school. I find it very interesting. As a musician, I find this knowlege to be very usefull.
  19. Well. There's a nice discussion, isn't it?;)

    Arvidgunardi, I don't own any of the equipment I mentioned. It was, I suppose, a hypothetical question but with real implications.

    Here's what happened. During a casual chat amongst musicians, a fellow bass player professed absolutely that a 4x15 will always be louder than a 4x10 because it moves more air on account of it having more surface area.

    That is what this thread is all about: bigger speakers are louder because they have more cone area to move more air. No more, no less.

    We agreed for the sake of sanity that you use one head and connect it between the two cabs. A bass player plays an identical piece in as near is as humanly possible an identical fachion.

    The guy maintained the 4x15 would be louder and wouldn't move from his point. I simply didn't know. So I asked on this board.

    That's about all there is to it, really.

  20. Actually, check out W. Marshall Leach, Georgia Institute of Technology. He has the book out that takes up where Vance Dickason leaves off. Lots of theory.

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