Which way to fire my sub?

[Ap]

Gee only one! Surely there has to be a time limit, maybe one a year?

[owdi]

Originally posted by nunayafb
Seriously, at sub freqencies sound radiates omnidirectionally so you can face it any direction you want. As far as downward, with the duplex situation I would avoid it, your goal should be to decouple the sub from the floor and downfiring will send the shockwave there first.

While low frequencies are omnidirectional, high order harmonics can be very directional. Pointing the driver away from the listener, and at some material that will absorb the harmonics, will make the sub more difficult to locate in the room.

Dan

[nunayafb]

Owdi, which harmonic frequencies are you talking about?
Most subwoofers have very low distortion in their upper range, distortion usually climbs as f goes down.
So the 3rd and 4th harmonics of a 20 or 30hz signal will still be low in frequency and hard to locate. In addition the only thing that can absorb these low freq. harmonics is bass traps or thick wall treatments, so now the harmonics will be reflected and time delayed.

This brings us right back to what everyone is saying, cross the woofer over low.

[Ap]

Exactly. In my setup I have achieved excellent results with subs poitning away from the main speakers on a side wall - not towards me.
It all depends on your room & your setup there is no one single best theory.

[mike.e]

Originally posted by zenmasterbrian
If you downfire, you can have a base plate.

But you have to be concerned about driver sag.

Also, I have never seen an analysis of how long the legs need to be on a down firing system. You need to be concerned about asymetrical driver loading.

AISI, down firing was more popular 15 years ago.

This is non-trivial. Loading of subwoofers with floor, walls, and corners does effect how they behave.

I would like to see a text where all the issues are analyzed.

Down firing is attractive because it can protect the sub better.

But it is less popular today, IMO. Driver sag? I don't know.

Asymmetrical loading : I need to be concerned,so where are your papers? If i was concerned about everything that wasnt proven,id be rather worried.All you need is enough area to radiate the sound,without any compression.

Adire has the sag paper.Its all based on the driver CMS.

Down firing seems popular with those all in one mini subs like wharfedale offer.

Losing 5% of your Xmax due to down firing means how much less SPL