Why we only need one subwoofer

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Viperoni

Lifer
Jan 4, 2000
11,084
1
71
Originally posted by: glen
Originally posted by: flood
Originally posted by: glen
What matters in subs is "swept air." This is the cone area times the X-mas, how far in and out it moves.
pi x R ^2 is area so:

a 15" sub has about a 74" surface area
a 12" sub has about a 59" surface area

to equal the potential volume at any given frequency, a 12" would ahve to have 25% greater excursion than the 15%.

some small exceptions:
a 12" in a band pass could have more output over a very narrow frequency range than say a 15" in a sealed enclosure.

Thats true for pure SPL, but when you factor in the quality of the sound youre getting, it gets a lot more complicated.

For sound quality, the larger driver has a real advantage because,
The tension on the spring and the resistance of the magnet are not linear!
Also, in almost all drivers, the larger the box, the flatter the response.

Still got your quad Tempest's glen?
Or am I thinking of someone else... ?
 

Linux23

Lifer
Apr 9, 2000
11,374
741
126
Originally posted by: glen
Originally posted by: flood
Originally posted by: glen
What matters in subs is "swept air." This is the cone area times the X-mas, how far in and out it moves.
pi x R ^2 is area so:

a 15" sub has about a 74" surface area
a 12" sub has about a 59" surface area

to equal the potential volume at any given frequency, a 12" would ahve to have 25% greater excursion than the 15%.

some small exceptions:
a 12" in a band pass could have more output over a very narrow frequency range than say a 15" in a sealed enclosure.

Thats true for pure SPL, but when you factor in the quality of the sound youre getting, it gets a lot more complicated.

For sound quality, the larger driver has a real advantage because,
The tension on the spring and the resistance of the magnet are not linear!
Also, in almost all drivers, the larger the box, the flatter the response.


actually by having a larger driver, you should be able to hit lower frequencies and louder SPL sound levels, but cone response is going to be slower than say a 12" sub. of course the 12" sub will not be louder and play lower than the 15" sub, but it will be able to change it's response much faster than the larger sub, thus producing less muddy bass.
 

bolsen

Senior member
Jul 31, 2002
288
0
0
Originally posted by: rudeguy5757
Bose=all high no lows

thanks, that is all

In HT, Bose isn't considered to be a worthy product. Their speakers are about $35 to make and they sell em for 1000

:|
 

Zim Hosein

Super Moderator | Elite Member
Super Moderator
Nov 27, 1999
65,409
407
126
Originally posted by: bolsen
Originally posted by: rudeguy5757
Bose=all high no lows

thanks, that is all

In HT, Bose isn't considered to be a worthy product. Their speakers are about $35 to make and they sell em for 1000

:|

Thanks for your opinion bolsen, do you have any links to back that up? I'm curious & :confused:
 

glen

Lifer
Apr 28, 2000
15,995
1
81
Originally posted by: Linux23
Originally posted by: glen
Originally posted by: flood
Originally posted by: glen
What matters in subs is "swept air." This is the cone area times the X-mas, how far in and out it moves.
pi x R ^2 is area so:

a 15" sub has about a 74" surface area
a 12" sub has about a 59" surface area

to equal the potential volume at any given frequency, a 12" would ahve to have 25% greater excursion than the 15%.

some small exceptions:
a 12" in a band pass could have more output over a very narrow frequency range than say a 15" in a sealed enclosure.

Thats true for pure SPL, but when you factor in the quality of the sound youre getting, it gets a lot more complicated.

For sound quality, the larger driver has a real advantage because,
The tension on the spring and the resistance of the magnet are not linear!
Also, in almost all drivers, the larger the box, the flatter the response.


actually by having a larger driver, you should be able to hit lower frequencies and louder SPL sound levels, but cone response is going to be slower than say a 12" sub. of course the 12" sub will not be louder and play lower than the 15" sub, but it will be able to change it's response much faster than the larger sub, thus producing less muddy bass.


YAAM
Yet another commonly held audio myth.
The large driver="slow" bass myth.
I need to write a FAQ.
 

kami

Lifer
Oct 9, 1999
17,627
5
81
Bose=all high no lows
You got the phrase wrong. You're givin em too much credit.

No highs, no lows, it must be Bose.

(yeah they don't have midrange either but you gotta give them something)


As for the original post I assume you mean subs for "surround bass" right? Cause adding more subs into a room increase the SPL quite a bit
 

Shockwave

Banned
Sep 16, 2000
9,059
0
0
Originally posted by: Linux23
Originally posted by: glen
Originally posted by: flood
Originally posted by: glen
What matters in subs is "swept air." This is the cone area times the X-mas, how far in and out it moves.
pi x R ^2 is area so:

a 15" sub has about a 74" surface area
a 12" sub has about a 59" surface area

to equal the potential volume at any given frequency, a 12" would ahve to have 25% greater excursion than the 15%.

some small exceptions:
a 12" in a band pass could have more output over a very narrow frequency range than say a 15" in a sealed enclosure.

Thats true for pure SPL, but when you factor in the quality of the sound youre getting, it gets a lot more complicated.

For sound quality, the larger driver has a real advantage because,
The tension on the spring and the resistance of the magnet are not linear!
Also, in almost all drivers, the larger the box, the flatter the response.


actually by having a larger driver, you should be able to hit lower frequencies and louder SPL sound levels, but cone response is going to be slower than say a 12" sub. of course the 12" sub will not be louder and play lower than the 15" sub, but it will be able to change it's response much faster than the larger sub, thus producing less muddy bass.

Thats completely wrong. A larger cone is actually preferable in a true audiophile setup (To an extent, not a requirement) It allows lower frequency extension without as much movement.
But, a larger cone is just as responsive as a smaller cone. That is determined by the motor, not the area of the cone.

 

flood

Diamond Member
Oct 17, 1999
4,213
0
76
From what I understand...
A larger driver will create a better response curve, but wont have the tightness of a smaller driver.
A 10" rel sub will sound a lot cleaner than that 15" audiosource sub costco had a deal on long ago.

Larger cone = greater moving mass + more cone flex

Its true that you can get a larger sub to sound better than a smaller ones, but all things being equal, the smaller one will sound better.
I guess the ideal sub is a servo sub like paradigms (I'm not familiar with other servo subs).

As for bose, I hate them!
Paper cones for highs and midrange??
Also, they never list their frequency response... I recall a magazine doing a test on their system and found it only went down to 80hz (w/sub)
 

tweakmm

Lifer
May 28, 2001
18,436
4
0
Originally posted by: Zim Hosein
Originally posted by: bolsen
Originally posted by: rudeguy5757
Bose=all high no lows

thanks, that is all

In HT, Bose isn't considered to be a worthy product. Their speakers are about $35 to make and they sell em for 1000

:|

Thanks for your opinion bolsen, do you have any links to back that up? I'm curious & :confused:
What he described is what every speaker manufactuer does,except for Bose it's probably $25 to make ;)