help me make sense of these BB6 Pro graphs (subwoofer related)

[Aharami]

I'll admit, I know nothing about audio. But I'm trying to learn as I want to build my own sub. While trying to compare GR-Research's SW-12B subs against the Dayton RSS390HF-4 15" sub from PE, I started playing with them in BassBox 6.

I drew up these two graphs, but I need some help in understanding what they mean.

Green is 2 SW-12B drivers in a 2.4 cu ft sealed box
Red is Dayton RSS390HF-4 in a 3 cu ft box

Also GR-Research claims that the SW-12B will, "In only a 1.2 cubic foot sealed box, and using this amp, and you will get a -3db down point in the mid 20's"

but my plot shows -3db down at 45 Hz. What gives?

I also drew up vented graphs, and those seem to be going down to the 20's
Grey is 2x SW-12B in a 4.6 cu ft vented box, tuned to 25Hz
Pink is Dayton RSSHF360-4 in a 4.6 cu ft vented box tuned to 25Hz

 

[kornphlake]

It looks like the Dayton wins in either a sealed or vented box. It really depends on what you're looking for though. I say the Dayton looks better because the curve is between 0db and -3db over a wider range than the GR Research driver. The Dayton will play a tad lower and if you needed it to for some reason it can play a little higher as well.

Generally a difference in SPL of 3db or less is considered imperceptible. Depending on what you expect the speaker to do you want the flattest curve in the range you want the speaker to perform.

There are some other nit picky things the impedance, phase response and group delay plots show but I think they are less important than the frequency response plots.

 

[vi edit]

All else being equal, I'd go for a 15" over a 12" almost any time if you can afford the space for the larger cabinet. It's very hard to go wrong with a 15" RS in a sealed configuration.

There simply is no replacement for displacement...although you can make a small argument for excursion.

 

[Aharami]

All else being equal, I'd go for a 15" over a 12" almost any time if you can afford the space for the larger cabinet. It's very hard to go wrong with a 15" RS in a sealed configuration.

There simply is no replacement for displacement...although you can make a small argument for excursion.

how about 2 12" drivers vs 1 15"?
thats how i set up those graphs above

 

[Howard]

Their quoted figures may be in-room. These would be anechoic, probably half-space.

 

[Number1]

Read the BassBox help file for a description of the graphs.

There is limited expertise here on speaker building. Check this site. diyAudio

I built these 2 kits, one for myself, one for my son.

CSS QUARTET12(TRIO12)B


CSS Trio12APR15


The quartet sounds slightly better and has a better radiation pattern.
I can forward you the BassBox files if you want.
I have both subs in my living room now. They actually induce pain in my ears because they move so much air and this at fairly low volume level.
One is more then enough. My room is 13' X 24'

F3 at 22 and 24 Hz.

The drivers are rated at 350 W and the Amps at 500W so you got to be careful not to crank the Amps too much.
I use the Onkyo TX-SR607 with the sub. An amp with sub equalization, Ie Audysey MultEQ, would make the subs sound even better.

Of course, You'll need a table saw and some wood working skills. See the construction process on my Smugmug gallery, sub #4

 

[Aharami]

Read the BassBox help file for a description of the graphs.

There is limited expertise here on speaker building. Check this site. diyAudio

I built these 2 kits, one for myself, one for my son.

CSS QUARTET12(TRIO12)B


CSS Trio12APR15


The quartet sounds slightly better and has a better radiation pattern.
I can forward you the BassBox files if you want.
I have both subs in my living room now. They actually induce pain in my ears because they move so much air and this at fairly low volume level.
One is more then enough. My room is 13' X 24'

F3 at 22 and 24 Hz.

The drivers are rated at 350 W and the Amps at 500W so you got to be careful not to crank the Amps too much.
I use the Onkyo TX-SR607 with the sub. An amp with sub equalization, Ie Audysey MultEQ, would make the subs sound even better.

Of course, You'll need a table saw and some wood working skills. See the construction process on my Smugmug gallery, sub #4

sweet. i'll look into diyaudio