Cone area vs motor force

[audiom3 10+ year member]

Ok so I was thinking yesterday about this- If you have one sub and it has 100in^2 of cone area and then you have 2 subs that also(hypothetically) have 100in^2 of cone area shouldn't the 2 subs be louder given that all variables are the same (wattage and box design etc). Also at what point is the added motor force of the additional sub overcome by the cone area of the fewer larger ones ex 2 15"s(353.25in^2) vs 3 12"s (339.12in^2). I am assuming that this is also dependent on the motor itself but I would think that there should be some general guidelines?????

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[Electrodynamic 10+ year member]

Ok so I was thinking yesterday about this- If you have one sub and it has 100in^2 of cone area and then you have 2 subs that also(hypothetically) have 100in^2 of cone area shouldn't the 2 subs be louder given that all variables are the same (wattage and box design etc).

Yes. With all other variables remaining constant, doubling your surface are yeilds you a 3 dB increase.

Also at what point is the added motor force of the additional sub overcome by the cone area of the fewer larger ones ex 2 15"s(353.25in^2) vs 3 12"s (339.12in^2). I am assuming that this is also dependent on the motor itself but I would think that there should be some general guidelines?????

Nope, not really. I wish it were that easy, but with there being more than one frequency possible it's hard to say that a higher motor force subwoofer will play louder than a lower BL subwoofer. As long as you've got enough force to reach the target cone movement per enclosure, frequency, and power level, anything else isn't necessary / won't do anything mind-blowing. Ever heard people complaining about Eclipse Ti's not performing well in small sealed enclosures? In that same size sealed enclosure a Brahama/Q/Mag/etc will play louder lower. The higher BL subwoofer actually performs poorer in that situation. Now change up the enclosures to a large ported enclosure and the Ti will shine. Yes motor force is a part of subwoofer design, but it alone does not dictate how the subwoofer will perform.

 

[audiom3 10+ year member]

Yes. With all other variables remaining constant, doubling your surface are yeilds you a 3 dB increase.

Yeah i knew that but what i was saying is if both smaller subs have a total of 100 sq in of surface area 50in^2 each so they equal the cone area of the larger sub

Also I understand that it would be dependent on the box but if you gave each sub its recommended enclosure volume regardless of the number of subs would the motor force make a difference?

 

[MisterGrubbs 5,000+ posts]

So basically

You're saying that IF the cone area of two 10's were the sam as a single 12, that the 10's should get louder?

I think that's the question.

 

[audiom3 10+ year member]

You are correct i was wondering if this would be true there was more to it but if someone has the answer to that i can go from there

 

[Electrodynamic 10+ year member]

Depending on subwoofer placement you may or may not see an increase. If they're close together you can get a tad due to coupling effect.

If two smaller subs had the equivalent Sd of single larger subwoofer, you're not gauranteed an increase in overall loudness just because there are two subwoofers.

If you had an amplifier that did 500 watts into a 4 Ohm load and also did 500 watts into a 1 Ohm load and you had a dual 2 Ohm subwoofer you wouldn't see an increase in output just from the increase in BL when wired in series. Well...not enough to hear.