12 vs 15, what’s the difference?

I realize that to some extent this is going to vary from sub to sub but IN GENERAL what is the difference between a 12 and 15?  Obviously I would expect a 15 to be louder, but other than SPL is very any benefit(s) to a 15?  Is it deeper, more detailed, etc? 

Incorrect on ALL of those fronts. I have seen 10" woofers go lower and play louder, with less articulation than a 15" driver.

Without knowing the specifications of the individual driver(s), you cannot say. Period.

Don't come back with "I said in general", because there is no such thing, seriously.

haemphyst wrote:

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Without knowing the specifications of the individual driver(s), you cannot say. Period.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

haemphyst wrote:

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Incorrect on ALL of those fronts. I have seen 10" woofers go lower and play louder, with less articulation than a 15" driver.

Without knowing the specifications of the individual driver(s), you cannot say. Period.

Don't come back with "I said in general", because there is no such thing, seriously.

haemphyst wrote:

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Without knowing the specifications of the individual driver(s), you cannot say. Period.

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Well...I wasn't really incorrect on ALL of those fronts because I only had ONE FRONT, which was that I expected a 15 to be louder...the remainder of what I said was clearly posed as a question.  I don't know if this changes anything, but when I say "in general" and when I said "a 15 will be louder" I mean with respect to a particular line or series of subs from a single manufacturer. ..for example comparing a 12" SSA icon with a 15" SSA icon, or a fi-Q Q12 vs a fi-Q Q15 etc.  When comparing subs given the aforementioned criterion are there typically some "in general" differences between a 12 and a 15, or is it still the case that "in general" doesn't apply?

Still no. Perfect case in point: The Eclipse Ti woofers. I had a 10" Ti woofer, and thinking I wanted louder still, I "upgraded" to the 12. Same amplifier, same "designed-and-built-specifically-for-the-driver" .707 aligned sealed enclosure, and the 10 was NOTICEABLY louder and deeper than the 12, in a significantly smaller enclosure (about one-third the size). The 12 did seem to have marginally more "impact", some said "faster", but the 10" woofer was a "better" overall driver. Obviously very different motor structures, their parameters were very different, and those differences all ended up in the favor of the 10" woofer.

There are no "generally speakings". It will depend completely what the manufacturer is trying to achieve with a given woofer design.

Now, with the same MOTOR STRUCTURE, and just a larger diaphragm bolted to the front of it, you will likely get "louder", but as I specifically stated "Without knowing the specifications of the individual driver(s), you cannot say" with certainty that one driver will be anything "better" or "different" simply by looking at it, and least of all, by addressing the diameter of the diaphragm alone.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

While haemphyst is correct in that there is a lot more to woofer performance than simple cone area, in my experience the basic difference one can expect with larger cones is not generally "louder" but "louder at the lowest frequencies."  Meaning a larger cone tends to have the ability to reproduce the lowest end of its range with higher SPL.  But, for reasons already described, this is only true when comparing two woofers that are otherwise very similar, such as in the same series from the same manufacturer.  Otherwise, there is no way to make a generalized statement other than a 15" will be larger than a 12", and therefor likely require a larger enclosure.

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DYohn] wrote:

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hile haemphyst is correct in that there is a lot more to woofer performance than simple cone area, in my experience the basic difference one can expect with larger cones is not generally "louder" but "louder at the lowest frequencies."  Meaning a larger cone tends to have the ability to reproduce the lowest end of its range with higher SPL.  But, for reasons already described, this is only true when comparing two woofers that are otherwise very similar, such as in the same series from the same manufacturer.  Otherwise, there is no way to make a generalized statement other than a 15" will be larger than a 12", and therefor likely require a larger enclosure.

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Thank you!  I get what haemphyst is saying but your answer touches on the "in general" I was looking for and makes me feel like a quality 15 may be the ideal woofer for me.  So would it be correct to say that if a particular woofer was able to play down to, say 20HZ, that one would expect (in general) that a 15 would out-perform an equivalent 12 in the 20-30hz range?  Note, once I get more serious about changing out my woofer I'll post some specific models so this isn't an "in general" discussion.

IMO, when comparing a 12" Mega-Boom Model X sub to a 15" Mega-Boom Model X sub, you should be able to expect the 15 incher to have higher output levels in the lowest frequency range, and it will be larger and require a larger enclosure.

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