wattage vs cone area

[fasfocus00 5,000+ posts]

just to satisfy my curiousity. would running 2 15 @1500 watts be louder and generate a higher spl than 1 15@ 1500 watts? I am considering running 2 AQ SDC2.515s with 1500 watts but my brother asked me why wouldn't I just run 1 HDC3.15. I told him that I'd have more cone area and be able to produce a higher spl, his response was "how so?". after this I really realized that I didn't have an answer for this. I've do systems with 1 10" woofer sound just as good as 2 10" and same with 12s and 15s. my real question is does more cone area at the same wattage yield a higher output?

Click to read more...

 

[Ed Lester 10+ year member]

Yes, 2 15" subs would displace more air volume thus creating a higher SPL than 1 15". Typically you may see a 3 dB increase

 

[Kyle_Keating 10+ year member]

You're talking about sensitivity, you have to look at more numbers than just cone size. In general, yes, most 15's are much louder than 10's with the same "watts"

lest break it down:

its very simple, SPL comes from displacement.

Sealed box

ported box

hornloaded box

Nth order box

it-does-not-matter

so if yo have more displacement you have MORE SPL, plain pure and simple.

here is why its confusing.......

getting displacement is not so simple. #1 it takes power which is completely different for each driver and system. For high SPL, you'll need a lot of it, but it hardly tells you how much SPL you're getting. There is MANY more numbers to consider here. You'll often see sensitivity figures posted, but more so you need to consider the system sensitivity and this is actually frequency dependent. When you get into system design, you need modeling software to calculate that or you need to bug and EE major and give you the down low on laplace transformations and signal processing... .good luck.

ok here is why it gets even more complex. Small signal measures are hardly a definitive way to rate a subwoofer, you can get the BL, and DC resistance of the voice coil, but in practice the displacement is not so easy to figure out because the these numbers change with respect to voice coil position and the amount of current applied. This is called non-linear transducer analysis and there are measurement systems like the klippel analyzer to figure out how the driver does at higher voltages. Its a very ignorant field of study when you design a driver

now what this means, if its very complex to figure out how much SPL you're going to get because its not easy to figure out exactly what kind of displacement your going to get at exactly a particular voltage at exactly a given frequency often times we just measure it. We can use softare and come up with very close approximations, however I cant promise you very few people go thu the effort to figure all that out so you often see blanket statements tossed out there

Bottom line, if you are even in the ball park of having a lot more displacement and you can use it (have the power), you're going to have a lot more SPL, remember displacement comes from many sources, for example, in the case of a ported subwooofer at resonance, the displacement comes almost entirely from the port. You can calculate exactly how much is is again using software... or math beyond most people here, but generally you can figure a port will move around 10 to 15" peak to peak at say...20Hz before serious drag compression occurs (1/4 of that at 40Hz), the funny thing about ports is that they are not limited by a suspension system like a passive radaitor, but rather by drag and drag is a non-linear function based off velocity which will be higher for higher tuning... so often times you need very large ports, even for higher tuning points if you want to minimize port compression, you can then use simply geometry to find the volume and compare that to an active woofer displaceamentwise.

serious, get bigger woofers, they are generally louder and sound better (lower distortion)

and never ever buy a 10" subwoofer unless you have forced by small spaces in your car.

good luck.

 

[fasfocus00 5,000+ posts]

so if i get this right I should nail it on the head, lol. There is no replacement for displacement.

 

[t-money 10+ year member]

the two 15's should be louder if both set ups are ported. If its two 15's sealed vs. one 15 ported, than it'll be close

 

[tcguy85 10+ year member]

some big *** tens out there.
but budget stuff....ill agree.

and that also depends on what your goal is. a single ten in the right box can be plenty for an SQ setup in the right car.

 

[Farva 10+ year member]

IMHO there is no replacement for displacement.

 

[jdawg 5,000+ posts]

IMHO there is no replacement for displacement.

thats what rednecks used to say about old V8's till they get stomped by a 4cyl with a turbo and get 30mpg to their 10mpg at that

 

[iowaaurora 10+ year member]

There is no replacement for displacement

 

[Farva 10+ year member]

thats what rednecks used to say about old V8's till they get stomped by a 4cyl with a turbo and get 30mpg to their 10mpg at that

Hmm, hypothetically with that train of thought, I guess that exact setups (vehicle, power, equipment, etc) but only changing the driver size, i.e. a ten and fifteen, that the ten will be just as loud as the fifteen? Sorry, but I find it hard to follow you.

Lastly, what supped up rice rocket or super car (running on gasoline) gets 30+ mpg during a race? Granted they are fast and can pull nice numbers but with greater power and torque comes more fuel consumption, right?