IS THIS TRUE?

[mclsound]

If one is going to crossover subs at 50hz,do you need to buy good($$$) 15 inchers?

[UV101]

Not sure what you mean. Many speakers will go below 50hz that are smaller than 15".

Surely it's more to do with the speaker parameters and enclosure design. At 50hz, I'm sure the room will play a part too.

[Inductor]

Originally Posted by mclsound

If one is going to crossover subs at 50hz,do you need to buy good($$$) 15 inchers?

I bet (without knowing) it has to do with SPL.

[fastbike1]

IMO the answer to your question, no matter the context, is no.

[Inductor]

Originally Posted by fastbike1

IMO the answer to your question, no matter the context, is no.

No, this is, if because SPL it can not cross to a small speaker (diameter) and with a high SPL and a small (one) number of drivers.

[Inductor]

Originally Posted by mclsound

If one is going to crossover subs at 50hz,do you need to buy good($$$) 15 inchers?

What is your plan anyway... (give us some specs.)

[SlainNothing]

bass is directional above 60hz ish.
good systems use the subs to play the super low end... <50hz
most low end monster subs do not like to play over >60hz.
therefore a 50hz crossover sub needs to be a good sub.
not always $$$ or size.
box type and size is a huge factor.
subs like this generally needs an active crossover. subsonic, low pass,& equalizer for good results.

my tc9 10" off 800rms loves 25hz-55hz ssf24db lp18db nothing else.

[mclsound]

what I mean is if you have great drivers covering all other frequencies but are looking for great subsonics crossed at 50hz/24db,would one be better off buying 2/side Aura NS18($1200/side) or say 4/side-15"($800/side)...I thought someone once said if you are going to cross at 40-50hz,you donnot need to buy such quality drivers???
I am wanting this in a reference designed 4.5way(My 4-12'AT woofers will hit 25hz and are crossed at 150hz).
Yes on SPL also,but clean,clear SPL.

[SlainNothing]

for the low end it is based on cone areas and displacement. and then budget. power concerns. box size.

two 18's of high quality may be smaller box. but more power needed. more displacement less cone area.
four 15 of lower quality may be huge box and less power. more cone area less displacement.

same results


cone area.
One 8" = 50.27
One 10" = 78.54
One 12" = 113.1
One 15" = 176.71
One 18" = 254.47

Two 8" = 100.53
Two 10" = 157.08
Two 12" = 226.19
Two 15" = 353.43
Two 18" = 508.94

Three 8" = 150.8
Three 10" = 235.62
Three 12" = 339.29
Three 15" = 530.14
Three 18" = 763.41

Four 8" = 201.06
Four 10" = 314.16
Four 12" = 452.39
Four 15" = 706.86
Four 18" = 1017.87

[mclsound]

Thanks Slain
I can get some Canadian made 15" subs(IST) for $199ea ..they are a sub used in the car industry(but are they not all used there).
2.5ft3 (sealed)ea will work well on these ...I see Aura ns18's will be back in Feb 2012 and will require 4-5ft3/ea..Power is no problem.
If Aura still had the 15"'s i would buy them.
TC Sounds are a little crazy in price for me.
I have a pair of CSS SDX 15's that I am experimenting with in a 3ft3 sealed box.I will keep them for my HT.
The other subs will be either side or rear firing in my modular mains consisting of..
SS 7100-hi
ATC 75/150"S"-mid
Volt-8" or 10"(experimenting right now)-mid bass
custom AT 12"-low
sub low-?
my design will be W.MB.MTM.MB.W with either side or rear firing subs