Sealed Sub- should the driver face up or down?

[Bill poster]

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]

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.

 

[Bill poster]

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.

 

[Bill poster]

I forgot to mention that the distance from sub(s) to back wall will be about 1.5 feet.

 

[nac134]

Don't bother with any kind of lens unless you are crossing it over really high.

 

[badman]

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.

 

[chris661]

I find it fun to watch the dust etc dance around on the cone.

Still, a reflector thingy could look cool.

 

[GM]

Ya'll seem to be forgetting the most important consideration........is the driver's specs suitable for up/down firing?

http://www.adireaudio.com/Files/DriverOrientation.pdf

GM

 

[nac134]

I had been working on the assumption that the subwoofer was to be installed on the international space station, rendering GM's point moot.

 

[Bill poster]

Ya'll seem to be forgetting the most important consideration........is the driver's specs suitable for up/down firing?

http://www.adireaudio.com/Files/DriverOrientation.pdf

GM

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.

 

[Bill poster]

I hope it works!

 

[riverwolf]

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