Just in case you forgot.....15's RULE

[wcriley]

...Speaker size also matters when it comes to moving air (SPL) - cone area.

How to calculate cone area.
Cone area = pi x (r x r)
pi = 3.14 r = radius of sub

# 8” 10” 12” 15” 18”
-----------------------------------------------------
1 50 78 113 176 254
2 100 157 226 353 508
3 150 235 339 530 763
4 201 314 452 706 1017
5 251 392 565 883 1272
6 301 471 678 1060 1526
7 351 549 791 1236 1781
8 402 628 904 1413 2035
NOTE: All numbers rounded down to the nearest inch.

Joe,
You've posted that chart a number of times here, but surface area (measured in 2 dimensions) only tells half the story. The amount (volume) of air moved must be measured in 3 dimensions. The missing dimension in your chart is the distance the cone travels back-and-forth. Without that, your chart is meaningless.

For instance:
An Eminence C2515 has a cone surface area of 856 cm^2 and an Xmax 4.5 mm, and a maximum displacement of 381cc.

On the other hand, an Eminence 3012LF has a cone surface area of 545 cm^2 (63% that of the C2515) but an Xmax of 9.1 mm (double that of the C2515), and a maximum displacement of 494 cc.

That means that the 3012LF can move more air than the CC2515.

 

[Ferdugan]

ok ok, what if your rocking a 5-string with a very low tuning? Can 10 inch drivers handle the low frequency as easy as a 15 inch can???

 

[dukeorock]

They also have poorer dispersion than a smaller speaker. Just sayin. IMO marrying yourself to a specific speaker size is just silly, find a cabinet that you like and go with that, regardless of what size speakers it has in it.

That said, I currently use two 115's.

Agreed, and well played!

 

[René_Julien]

ok ok, what if your rocking a 5-string with a very low tuning? Can 10 inch drivers handle the low frequency as easy as a 15 inch can???

Very generalizing... yes.

Some even better than a 15". Depends on the cab how it is tuned.

 

[Joe Louvar]

Joe,
You've posted that chart a number of times here, but surface area (measured in 2 dimensions) only tells half the story. The amount (volume) of air moved must be measured in 3 dimensions. The missing dimension in your chart is the distance the cone travels back-and-forth. Without that, your chart is meaningless.

For instance:
An Eminence C2515 has a cone surface area of 856 cm^2 and an Xmax 4.5 mm, and a maximum displacement of 381cc.

On the other hand, an Eminence 3012LF has a cone surface area of 545 cm^2 (63% that of the C2515) but an Xmax of 9.1 mm (double that of the C2515), and a maximum displacement of 494 cc.

That means that the 3012LF can move more air than the CC2515.

But not more than a 3015LF but thanks for the info.

EDIT: PS - I added "generally" to my post.

 

[dukeorock]

A 15" by itself....nada. Never heard one that had a nice tight punchy sound with lows that are not muddy. I like to be able to actually hear the notes. Not just feel them!

I switched over to 10"s back in 1988 (my first was a Trace Elliot 4x10) and have not looked back!

Now a 15" cabinet coupled with a 4x10 (even a 2x12), that is a whole other story. You can get some killer sounds from that!

*sigh*

 

[Joe Louvar]

Another example of how little dispersion matters in the real world is two identical 10s crush a single 10 even though a single 10 has better dispersion. And the 410, 610, 810, etc don’t have the best dispersion ether - but who cares.

 

[tjnkoo]

*sigh*

If it sounds good it sounds good, glad you found a sound you're into. I have a feeling the *sigh* is coming from mixed cabs? There are exceptions.

 

[dukeorock]

If it sounds good it sounds good, glad you found a sound you're into. I have a feeling the *sigh* is coming from mixed cabs? There are exceptions.

Naw, I aint busting your chops about that, bro...it's just "a 15 with a 410..." What does that mean? Typically it's a horrid combination for very good reason...but there was no mention of WHICH 15 with WHAT 410?!...kinda misleading for a beginner wanting to learn about this stuff...it suggests that any 15 and any 410 is awesome together...it was a statement with a complete lack of any actual meaning, and can lead folks down some silly, money wasting paths...that's all

 

[georgestrings]

Bigger gigs??? - this rig could pretty much handle any gig you could throw at it:

 

[georgestrings]

I do also like 15s, though:

 

[René_Julien]

It's all in marketing and convenience for retailers. I blame them but as a business man I understand them too.

An ad from a manufacturer usually show a stack with a 410 and a 115. The main reason for this is showing as much products that they offer on limited space. "See, we make a 410... also, we make a 115."
Also in showrooms. It makes more sense for stock and inventory for a shopowner to display stacks of 410+115. Not as much to invest and doesn't take the space of two rigs.

Especially the smaller stores (mom and pop stores) would be hesitant to stock 2 of the same cab, twice the investment.
If there weren't any slant guitarcabs you probably would see less guitar fullstacks as well in the showrooms.

 

[MJ_Sotti]

I love 15's but my 2 410HE's (the old 200w ones) are really nice.

It's the baby SVT...VT bass as preamp, PF350 for it's power amp and the HE's

 

[tjnkoo]

Naw, I aint busting your chops about that, bro...it's just "a 15 with a 410..." What does that mean? Typically it's a horrid combination for very good reason...but there was no mention of WHICH 15 with WHAT 410?!...kinda misleading for a beginner wanting to learn about this stuff...it suggests that any 15 and any 410 is awesome together...it was a statement with a complete lack of any actual meaning, and can lead folks down some silly, money wasting paths...that's all

I totally understand, I'm not the one who said he had the mixed rig though, I was just defending his sound. I myself use a single 15' Ampeg portaflex rig with the direct out. I completely agree that not all cabs sound good together, haha.

 

[dukeorock]

I totally understand, I'm not the one who said he had the mixed rig though, I was just defending his sound. I myself use a single 15' Ampeg portaflex rig with the direct out. I completely agree that not all cabs sound good together, haha.

There we go! That's all I'm getting at...to say a speaker size isn't very meaningful unless we say which speaker, which enclosure and why we like it

 

[HolmeBass]

I voted carrots- because speakers of a certain size do not all sound the same. Speaker size is only one component of a complex solution to a bass cabinet design. Not all 115 boxes sound the same, nor do all 215s sound like each other- and not all 410s sound the same. You really want to compare particular solutions, say Mesa's 215 againt Berantino's 610 or 412 against the Ampeg 810 fridge. Blanket statements about "15s rule" are not really meaningful, unless you just like the way they look.

 

[B-string]

Many people listen with their eyes

 

[dspellman]

How to calculate cone area.
Cone area = pi x (r x r)
pi = 3.14 r = radius of sub

# 8” 10” 12” 15” 18”
-----------------------------------------------------
1 50 78 113 176 254
2 100 157 226 353 508
3 150 235 339 530 763
4 201 314 452 706 1017
5 251 392 565 883 1272
6 301 471 678 1060 1526
7 351 549 791 1236 1781
8 402 628 904 1413 2035

FWIW, you should retire this table, since it's incorrect (it doesn't take into account the surround when figuring actual cone diameter). For example, the actual size of a 15" speaker's cone diameter will be closer to 13.2", the actual area would then be 136.7" rather than 176" (using the formula). It's probably not even quite correct proportionally, since the surround doesn't necessarily reduce in size proportionally to the diameter of the speaker.

 

[Mystic Michael]

But I like all kinds of speakers, from 8" to 18" (and even Phil Jones 5"). It really depends on the cab itself.

No fair being open-minded and tolerant. If you can't be as dogmatic as the OP, just don't play!

MM

 

[Joe Louvar]

FWIW, you should retire this table, since it's incorrect (it doesn't take into account the surround when figuring actual cone diameter). For example, the actual size of a 15" speaker's cone diameter will be closer to 13.2", the actual area would then be 136.7" rather than 176" (using the formula). It's probably not even quite correct proportionally, since the surround doesn't necessarily reduce in size proportionally to the diameter of the speaker.

Hmm, then please fix it for us/me and repost the correct formula and table -thanks.