Sealed Sub- should the driver face up or down?

Because of the shape of the sub I am making (kind of a shallow spherical shape, like a UFO).

I have a choice of upwards on downwards firing only. There will be plenty of space underneath if the woofer is firing downwards but I'm thinking that because its a sealed unit, will it need to face upwards to get bass support from the floor?
 

nac134

Member
2008-09-04 1:47 pm
You will probably find that facing the sub upwards will give a particularly clean sound, though you will get more thump facing it down. I have done this several times myself, and I like upward facing - just be mindful that the woofer will collect dust.
 
You will probably find that facing the sub upwards will give a particularly clean sound, though you will get more thump facing it down. I have done this several times myself, and I like upward facing - just be mindful that the woofer will collect dust.

Thanks for your answer. I was leaning towards upwards facing and I will try and make some kind of 'lens' above the woofer to reflect the sound and also act as a dust cover.
 
Either or will work, I have used both. You get floor reinforcement either way (wavelengths are huge relative to the enclosure height), there are only minimal differences in wave performance, but upfiring gives more delay but less destructive interference to distortion artifacts. No reasonable lens will do anything for directionality at these frequencies but could be used to prevent dust/look cool.
 

riverwolf

Member
2009-04-29 11:14 pm
I'm crap at working that stuff out;) seriously don't try to teach me! Win ISD ok but not this stuff...

I'm wanting to use the HiVi M8a.

WinISD Pro does the sag calculation for you. Look in the driver editor on the "advanced" tab. The value is GLoss%. The ROT is stay under 5%, but you might want to Google for discussions of driver orientation to come up with your own conclusions about the potential issues with up/down firing.

-Brent