Up Firing

[Fazorcat]

I have my subwoofer facing upward... so an upfiring subwoofer. Is there any advantages or disadvantages to this?

[BassAwdyO]

Advantages are questionable.

One thing that might be considered an advantage is better mechanical coupling. IE if you play a 30hz tone, with your subs vertically firing it takes about 3db less in my experience to make the walls rattle just as much as horizontally firing subs.

This is because the inertial forces caused by acceleration of the cone will cause the box to move slightly and this transmits a small amount of mechanical vibration to the floor.


Disadvangages:
Cone sag
harder to protect the speaker

[Bill Fitzpatrick]

For an average ceiling height of 94" there will be a room mode at about 70Hz. The intensity of this mode at the listening position will vary with woofer height. A case can easily be made for a top firing woofer with a position considerably off the floor. In my case I have, per channel, two stacked front firing woofers, one centered at 13" off the floor and the other at 30" off the floor.

[Fazorcat]

What is cone sag exactly? And would I need to worry about it with a Brahma 15?

[BassAwdyO]

well the cone of a driver can move in and out, up and down, whatever you want to say. But it basically moves one direction or another in a line, ideally. Well just like some tig ol bittys will sag, if your driver is mounted vertical, the cone will sag just a bit. This is due gravity of course.

Is this going to hurt your brahma? maybe

Looking at the DUMAX BL curves adire has on their website the magnetic center of the 12brahma markI is at 2.44millimeters positive excursion(cone moving away from the motor).

Considering that the brahma line uses the same motor for each size(or so it would look from the eact same BL XMax Le and Voicecoil resistance) I would guess the 15" has the same magnetic center and thus would be best mounted downfiring. Now if the sub is on the top of the enclosure, and the driver is downward facing, you'll get to look at that pretty magnet.

[Fazorcat]

Here is what my subwoofer looks like.... it's in the closet and it pounds.

http://img29.exs.cx/gal.php?g=adirebrahma15inbox0qh.jpg

My problem is that I set a 15" grill over the speaker when I'm not using it so my cats don't jump on it and hurt it,a nd to protect it from anything else. But I am getting tired of putting on and taking off the grill every time I want to use the sub. Is there something I could build to protect it? I can't lay it down, so it needs to be upfiring. Maybe a plexiglass top or something... cause I like to see this monster move. But I don't want to sacrifice the sound. Any other options? Would that work?

[Bill Fitzpatrick]

Install a welded wire mesh screen and keep it on.

[xstephanx]

There are some very nice looking grills over at partsexpress right now, Take your pick!

http://www.partsexpress.com/pe/showd...number=260-444
http://www.partsexpress.com/pe/showd...number=260-445
http://www.partsexpress.com/pe/showd...number=263-167

Im a fan of the bar grills, theyre pretty tall so they can handle high excursion woofers, and if you dont think theyre tall nuff for your brahma, then just take a piece of 3/4 mdf, and glue it ontop of your current baffle, and then mount the grill to that, giving it an extra 3/4 of height!

[Fazorcat]

Thanks for the replys... those bar grills look pretty cool. I might go with those. Would it be a bad idea to mount a piece of thick plexiglass over it raised about 3 inches? Cause that would keep dust out of there too. I'm wondering if that would affect the sound.

[xstephanx]

the problem is that if you mount something like a pannel, too close to the driver, you start to acoustically load it, lowering its FS i believe.

I suppose you could just mount a plate of plexiglass like 4" above the sub, then you wouldnt need a grill, but i wouldnt go any lower than 4"

I am also aware that the SVS subwoofer cylinders have the bottom plate a little under 3" from the driver, but i have heard that this is intentionally loading the driver.