brand specs , f3

Ok, looking at specs in my catalogs I have to figure I'm missing some thing because Major brand vs. Not as big company:

RMS power almost equal

Sensitivity close (major brand narrower)

Sensitivity 86(major) - 92(minor) ???

Now, assuming numbers are correct, and in the correct sized boxes for each driver, would the "Not as big company's" driver produce louder bass? And am I missing something of importance here?

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This is harder to explain but, if comparing freq. response of two subs, same model, different sizes if the 15's range is shifted slightly downward, (compared to 12) would the 15's peak spl/sq "sweet spot" be lower than that of the 12 assuming they have the same motor structure?

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Also could someone give me some help (explinations) on F3, searching only brought up "f-3"50 installs. -Thanks.

1. Why don't we have a look at the two brands / models you are talking about so we don't have to talk in generalities about those component woofers' specs.  If you want to go on the assumption that both speakers' ratings are perfectly correct, it doesn't matter at all that one company is well known and the other a fledgling.

2. A ''sweet spot'' is an arbitrary freq range and is dependent upon the enclosure, the vehicle, the listener's hearing and his expectations of what sounds best, the type of music...and more, I'm sure.  That's a few good reasons why ''sweet spot'' isn't a term used in that regard.  You might use the term when talking about the front soundstage and things related to stereo sound.  I rarely hear it except from some who like to talk about home theater.

All things relatively equal, a 15 will produce the lowest freqs better than a 12, but the music played through the two subs is still the same music.  Most popular music has very little usable content in the low freqs where a 15 might be contrasted with a 12.  The sub is crossed over to the front speakers at a low freq relative to its ability to play higher tones, so any comparisons concerning the high end of the freq range is not an issue either. 

A vehicle's cabin gain acts as somewhat of an equalizer, too, as 12's can sound and feel more like a larger diameter sub...unlike results you might find in a home audio environment.  For car audio, 15s are not first choice sub size unless for special reasons.  Enclosure size requirements has a lot to do with that, as well as choice of subs in the marketplace.

3. F3 is the point where the music has dwindled in loudness to -3 db from the reference point.  It's  considered the low end of the woofer's usable freq range because at -3 db it is at half the accoustical power output as the reference.  Read my guide Using WinISD and click on the links as you go through.  You'll see definitions of speaker parameters and common terms as well as frequency graphs.

ahh thanks, I finally get the F3 now, no one ever put it in referance to the end of the usable freq range

thanks for your help

ok comparing:

http://www.crutchfield.com/S-xkv9yK81JSj/App/Product/Item/Main.aspx?i=500SWR1242

http://www.crutchfield.com/S-8fjVLlxMjyj/App/Product/Item/Main.aspx?i=500SWS1223

http://www.powerbassusa.com/products/subwoofers/2xl_subwoofers.html

2xl-12d^

I own the typeRs and just picked up a side set of typeSs cheap, but I'm thinking of selling the typeRs for some PowerBass 2xl-12ds.