If shooting for SPL, should you maximize cone area for constant wattage?

[michaellane 5,000+ posts]

I went from a AQ hdc3 12 to four 10's. the 10's have a jl w6 motor and basket and credence soft parts. all was run off a nine.1.

so 1200rms to the 12 and 300rms to each 10.

 

[kodak314 10+ year member]

Well no shit. That's 412sq of cone area versus 1256sq. You more than tripled your cone area. You'd have to majorly downgrade to have four tens quieter than one 12.

where u getting these numbers from?

 

[spltuscon 10+ year member]

My advice would be to find efficient subs and build an efficient (as large as possible) box for them. In your case, 4 twelves that don't require a lot of power would probably be your best option.

 

[SomeGuyDude 10+ year member]

where u getting these numbers from?

I mistakenly assumed he meant he went from a single 12" to four 10" subs.

A=pi*r^2

12*12*3.14=452.16

10*10*3.14*4=1256

Now if he's talking going from ONE 12" to FOUR 12" subs then yeah it's just a simple quadrupling of cone area in which case my original point is only more true. You switch from one sub to four at the same size and unless you went from like a XXX to four Bazookas your output is obviously going to be way higher.

 

[Stalin-ohaulic]

If you have limited power, you have to look at both power usage and cone area. If you have 1800 watts at your disposal, four 12's aren't going to do you any good if each of them needs 800 watts, but a pair of 15s would do pretty well.

Literally everything you've said in this thread is incorrect. What do you mean the sub "needs" 800 watts? No sub "needs" any specific amount of power. The rms rating is not a reference on how much power to give the sub so that it reaches some magical land of potential. It is the thermal power handling limit of the voice coil.

The sub's efficiency through the frequency range you're going to be playing it at determines how loud it will be on what power. Of course the only efficiency calculation we have available to us is for the sub at frequencies WAY higher than we'll ever play through it and are basically useless to us... but if we had one that could tell us what the efficiency of the loudspeaker was at 1w@1m for 20hz, 45, and 80hz, we might be able to have a good idea which sub would be louder than another and how much power it needs to suit our needs. Any wattage below RMS is what a sub "needs". Geez, you dolts on this forum need to stop spreading your misinformation.

Also, your cone area calculations are WAY off. It takes work to be wrong EVERY time. You must be working hard at it.

 

[marcotheclepto 10+ year member]

I mistakenly assumed he meant he went from a single 12" to four 10" subs.
A=pi*r^2

12*12*3.14=452.16

 

10*10*3.14*4=1256

Now if he's talking going from ONE 12" to FOUR 12" subs then yeah it's just a simple quadrupling of cone area in which case my original point is only more true. You switch from one sub to four at the same size and unless you went from like a XXX to four Bazookas your output is obviously going to be way higher.

math is wrong 12is the diameter... 6 is radius of 12 in circle... also cones are usually not flat so surface area is off from that as well....

 

[marcotheclepto 10+ year member]

Literally everything you've said in this thread is incorrect. What do you mean the sub "needs" 800 watts? No sub "needs" any specific amount of power. The rms rating is not a reference on how much power to give the sub so that it reaches some magical land of potential. It is the thermal power handling limit of the voice coil.
Also, your cone area calculations are WAY off. It takes work to be wrong EVERY time. You must be working hard at it.

x2 on being wrong...

 

[ThatChevyGuy 5,000+ posts]

bigger box=more efficient

and aero ported, with plenty of port

 

[gsuchyta 10+ year member]

Look into 4 12" incriminator audio 187's Don't require that much space and will do good on 400 watts on each sub. That would be my reccomendation

 

[SomeGuyDude 10+ year member]

math is wrong 12is the diameter... 6 is radius of 12 in circle... also cones are usually not flat so surface area is off from that as well....

LOL, I'm having a slow day. I even wrote R for radius and STILL used the **** diameter. Forgive me on that. The proportions still maintain though.

 

[spencer321 10+ year member]

math is wrong 12is the diameter... 6 is radius of 12 in circle... also cones are usually not flat so surface area is off from that as well....

your correct but the magic number is effective piston area, and we've actually done the math together the depth of the cone makes no difference in effective piston area at all (i know it looks like it should but theres a huge thread on here disproving the fact)

a decent estimate for such is

310cm^2 for 10's

480cm^2 for 12's

810cm^2 for 15's

and 18's vary from 1000-1200cm^2

so 4 10's would be 1240cm^2 which is 2.58x's a single 12

 

[spencer321 10+ year member]

bigger box=more efficientand aero ported, with plenty of port

THANK YOU thats what i was looking for, what makes a system efficient

so larger box more cone area and aero ports would get me the most for my wattage?

 

[tez4life Premium Member]

i went from a single 12 to four lower rms subs and they walk all over my single sub...

I did just the oppisite, went from 4 lower RMS 12s (350w each) to a single 15" (1000w RMS) and it walked all over the 12s on around the same power.

Now that I think about it, the 12s had more power. Im running a single 18" now and its way louder than the 15" was.

My vote is a nice large sub, depending on how much space is ava.

 

[herbykw 10+ year member]

I had a AQ2200 running 2 15" L7s, now i am using the same amp pushing my 18" Solo X and it DOMINATES the L7s on the same power.

I did think about going from my 18" to 4 12"s... but i dont know.....probly not

 

[spencer321 10+ year member]

I did just the oppisite, went from 4 lower RMS 12s (350w each) to a single 15" (1000w RMS) and it walked all over the 12s on around the same power.
Now that I think about it, the 12s had more power. Im running a single 18" now and its way louder than the 15" was.

My vote is a nice large sub, depending on how much space is ava.

what 12's to what 15?