New Subwoofer!

Brian Bunge · « **on:** 3 Feb 2003, 04:11 am »

I just completed my enclosure for my new Adire Audio Tumult based subwoofer. I can't wait for the driver to come in. The enclosure and my Crown K2 amp are waiting!

http://www.rutledgeaudiodesign.com/subwoofers.html

Al Garay · « **Reply #1 on:** 3 Feb 2003, 06:12 am »

Nice job Brian.

I hope your Tumult arrives soon. It's too bad about the delays.

If you have already spent $1,000 plus, why not use real marble or granite?

Do you think downward firing causes any damage to the woofer? I have read that it is not optimal ... who cares if you get 4-10% less output than forward firing. The Tumult will have plenty. However, I am worried about possible damage to the drive itself.

Thanks,

Al

Brian Bunge · « **Reply #2 on:** 3 Feb 2003, 06:16 am »

What type of damage? ACI has been building subs with downfiring drivers for years. They have little to no driver failure. This is per Mike Dzurko himself.

Brandon B · « **Reply #3 on:** 4 Feb 2003, 02:22 am »

Apart from damage concerns, the other issue about down firing is since the driver's neutral position will sag slightly below center, you have just shifted it from the optimal performing position. Operatioon is most linnear in the center, more distortion as you get to the limits

Only slightly though, so it's probably a matter of preference. Last 1/10th of a percent of performance or less kind of thing. Did Adire say their was any problem downfiring the driver? If not, I wouldn't worry.

On the other hand, your that much less like to to bottom the driver out CLACK!

BB

Brian Bunge · « **Reply #4 on:** 4 Feb 2003, 02:26 am »

Brandon,

I don't know that you'll have to worry about bottoming a Tumult. I imagine your house will fall down first!

Brandon B · « **Reply #5 on:** 4 Feb 2003, 03:27 pm »

Well, I am running a single HE15 (I have a second, but have not found the time to build the enclosure for it), and I can bottom it out pretty easily. Running it off half a Crown MA3600vz.

Reason? My theater room is a 15x35 9' ceiling kitchen/family room, but is wide open to an 18' ceiling living room and upstairs hall area. All sitting on a bass-sucking concrete slab. I can bottom out ANY single sub driver without reaching reference on quite a few movies: LOTR, SW Ep I and II, TSII, Titan AE, etc.

So what I thought was overkill originally turns outto be just enough.

But seriously, I was saying there's no real reason the tumult should not be bottom firing, unless Dan W says so. John J at Stryke recommends against doing this with the HE15.

BB

audiojerry · « **Reply #6 on:** 4 Feb 2003, 04:31 pm »

Beautiful work Brian! Could you do that faux marble to the cabinets for the GR Criterions? How much, or would you prefer to email me on this?

Brandon, I have read that large, heavy drivers will suffer more over time when mounted in the usual vertical position than in a down firing position. The reason for this is that the weight of the cone material causes it to sag downward due to gravity, and this offets it from its ideal centering around the magnet gap. This eventually will lead to rubbing. For large woofers, it is recommended that you turn them upside down every year or so, and leave them that way for another year or so. I had a large 12 year old 15" paper cone woofer that sagged exactly in this way. You could even see that it was drooping downward, and when you pushed the cone inward, you could feel and hear it rubbing against the vc. If the driver is downward mounted, it will remain centered around the gap, even as it sags downward due to gravity. which I'd guess is a better compromise.

Brian Bunge · « **Reply #7 on:** 4 Feb 2003, 05:34 pm »

Quote from: audiojerry

Beautiful work Brian! Could you do that faux marble to the cabinets for the GR Criterions? How much, or would you prefer to email me on this?

Sure it can be done. I'll just have to talk to the artist and see what she charges. Drop me an email and we'll discuss further: [email protected]

Quote

Brandon, I have read that large, heavy drivers will suffer more over time when mounted in the usual vertical position than in a down firing position. The reason for this is that the weight of the cone material causes it to sag downward due to gravity, and this offets it from its ideal centering around the magnet gap. This eventually will lead to rubbing. For large woofers, it is recommended that you turn them upside down every year or so, and leave them that way for another year or so. I had a large 12 year old 15" paper cone woofer that sagged exactly in this way. You could even see that it was drooping downward, and when you pushed the cone inward, you could feel and hear it rubbing against the vc. If the driver is downward mounted, it will remain centered around the gap, even as it sags downward due to gravity. which I'd guess is a better compromise.

The Tumult was designed specifically to be able to handle downward firing. Cone sag isn't that much of an issue if the motor structure is strong enough to hold the voice coil in the magnetic gap. The HE15 was not designed for downward firing. And some drivers are designed to not be capable of bottoming (coil hitting the backplate) but you can drive it past it's suspension's limits (the surround). That wouldn't be good either.