Quote:
Originally Posted by Gill  - Size: 8 inch
Sensitivity: 85.4 dB
Frequency Response: 10-150 Hz
RecommendedRMS Power: 50-300W
Peak Power Handling: 350W
Impedance 4 ohms
- Size: 12 inch
Sensitivity: 88.6 dB
Frequency Response: 10-150 Hz
Recommended RMS Power: 100-300W
Peak Power Handling: 400W
all of them gonna touch same low's n high's what ever th respective figures are!! |
these specs do not give you a complete picture of the subwofoer's performance. To get even a partial picture you need what are commonly called Theil-Small specifications. These specifications will include figures for
Free Air Resonance Frequency (Fs)
Mechanical Qms
Electrical Qes
Equivalent Volume (Vas)
Moving Mass incl air (Mms)
Compliance (Cms)
etc...
that said lets consider a 8" vs a 12" (the 10" will fall somewhere in between).
a 8" has a Surface of about 200cm2, a 12" about 400 cm2 so the 12" can usually move atleast twice as much as as an 8" hence it can play louder with less effort.
a 12" because of it's higher mass (larger cone is usually heavier than smaller cone) also has a lower Fs (resonant freq) and higher Equiv. Volume (Vas). This means that if you can afford a bigger box and your midbass dirvers can go low enough you would be better off with a 12" instead of a 8".
Choosing a subwoofer hence is not just a matter of how loud you want to play (although that is one factor) it is also a factor of how low do you want to go, how will the subwoofer mate with your other speakers, how big a box can you afford, what style of music do you listen to etc...
I'll give you an example. in my car I have 13cm midbass drivers. Initiall I had a pair of 6.5" woofers (I have very limited space) to help with the bass (notice I did not call them subwoofers). ANyway some days later I managed to build a custom fiberglass box with a 12" woofer into one the niches of the trunk and hence thought i could do away with the 6.5" woofers.
On crossing my 13cm woofers I ntoiced that they could not delvier the SPLs I wanted below 150Hz or so. My 12" however made itself very noticeable (all bass coming from the rear) if asked to go above 80Hz. Hence there was a full octave gap (80-150Hz). The solution in my case was to let the 13cm woofers operate more like midranges and cross them at 200-250Hz then let the 12" be XOed at 60hz and let the 6.5 " woofer I was going to discard operate over the 3 octaves between 60 and 200hz. This is not a ideal solution. I did this becuase I am a cheapskate and hate to discard stuff, ideally i should have changed the 13cm woofer to ones that could go lower and the sub to one that offereed better response higher up and more.