Sonotube Subwoofer

[DeFriend]

I have used the Omega 15 Pro drivers, but they fail really bad when asked to perform for sub duties. 4.8mm xmax will bottom the driver out quickly when asked to perform in the sub region. A SUBwoofer means below 20hz. Lots of regular woofers play 30hz on up fine. But ask them to play a 16hz pipe organ note, or reproduce single digit frequencies found in modern movies and they run out of excursion capabilities. If you use DSP, then it limits the output to protect the driver, then you end up with insufficient spl. As the old saying goes, " there's no replacement for displacement " Measuring the response that is produced in the room with a calibrated mic and a PC waterfall program, will reveal 3-10hz output in movies these days, with a large displacement driver that can travel 4" peak to peak. When a driver is restricted due to an electronic protection circuit, 40-60db output cannot be even felt.

Everyone has their reference, and "Contentment is destroyed by comparison ". I always chuckle when someone says that their 8" XXX brand of subwoofer with 100 watts "shakes their whole house". It's just like living in a small town that has a VW bug, a Taurus, and a Mustang. Everyone knows the Mustang eats the other two up. Then a McClaren supercar comes up and gives everyone a ride in it. After that nobody wants to ride in the other 3 anymore.

Look at the Lavoce driver from Parts Express, and the frequency response, it starts rolling off at 90hz. Their specs say 40 hz is the bottom of the frequency range, meaning it won't even play below 20hz in the real world with only 1/2" of linear travel. Through the years, if I bottom out a sub, I get rid of it and buy something that won't.

Hobie,
I am certainly aware of the shortcomings you mention, and am still hoping to replace the driver someday.
I've even considered a pair of drivers face-to-face in push-pull, but both would have to be on exterior of baffle due to practical considerations (It would be difficult to hold lower driver in place while installing the bolts from above).
The 3-10 Hz output doesn't matter; there is not a single video screen in my music room.
Although I do like Saint Saens Symphony #3 (minty 1980 Michael Murray on Telarc vinyl) and other organ music, it is not part of my regular rotation.
I specifically use my miniDSP to cut frequencies below 10-15 Hz.
I could certainly use more xmax, but 4" peak-to-peak can be awful for music because of the Doppler effect; I don't really want my 40 Hz bass modulated by riding on a cone that is also rumbling at 10 Hz.
(and this type of driver didn't even exist 10 (15?) years ago when I pulled the trigger on the Omega 15 Pro)

Is there no compromise between pro-style drivers and the weird automotive-competition drivers that are now commonly re-purposed for home use?
As I run bridged mono with a hi-fi/mid-fi amplifier, I would need to stay around 8 ohm nominal for a single voice coil, or 4 ohms if dual voice coil (or two drivers in push-pull).
Every time I have searched, I have failed to find a driver with specs that tick all the right boxes.

(just to be antagonistic and off-topic, I am willing to bet a modern VW Bug/Jetta/Passat rides Much better than a McClaren, just a fair bit slower. Speaking of small towns (and the city) I really don't understand the popularity of trucks; the ride is a turd that just cannot be polished.)

 

[Hobie1dog]

Hobie,



Is there no compromise between pro-style drivers and the weird automotive-competition drivers that are now commonly re-purposed for home use?
)

Not that I'm aware of.

 

[blackburb]

On the subject of "other than Sonotube" tubes, I have one I built many years ago that's a 15" dia tube, 1/2" thick. I acquired the tube from a local classic car restoration shop. The owner said he had received a headliner rolled up in it. This was before the internet was a "thing" and I had no reason, or interest, in determining where the tube actually originated. I'm sure google has options if something other than standard Sonotube is desired.

For smaller sizes, there are a gazillion sizes of wire spools with cardboard tube centers. I know because I still have a dozen or more in my basement. A coax car speaker in the end of a small tube and you have an inexpensive, point-source desktop speaker (if you don't like car speakers, you can hot glue your choice of tweeter to the inside of a metal grill over your choice of woofer. Yes, I'm well aware the tweeter forward of the woofer isn't ideal, but we're talking bargain stuff for casual listening here...)

 

[swechsler]

I'm going to be on the lookout for a larger Sonotube (Home Depot only carries up to 12" diameter). I have a JL Audio 12W7 car subwoofer that can get flat down to about 20 hz in a large ported enclosure. It didn't even occur to me before but I think Sonotube is the answer (actually they don't even carry Sonotube, it's Quikrete brand, which works fine for deck footings, not so good for large subwoofer enclosures).

 

[Hobie1dog]

Anyone who is looking for a tube as an enclosure should Google up their local Building Supply houses, and a few quick calls will usually give you a selection of sonotubes used specifically for the concrete forms this will give you the much bigger sizes that most of us require as in 20 22 and 24 inch versions. And remember that the pressures inside of a cylindrical tube are distributed equally so there really isn't a lot of pressure on the inside of the enclosure it's almost the world's perfect enclosure for a subwoofer.

 

[fill35u]

I'm going to be on the lookout for a larger Sonotube (Home Depot only carries up to 12" diameter).

I got my 24" Sonotube from A.H. Harris supply (now owned by Home Depot!). The 12 foot length wasn't cheap, definitely more than 3/4" MDF would've been to enclose the same volume. But Sonotube permits the lightest weight construction.

 

[DeFriend]

Reviving an old thread.
I upgraded to a proper driver a couple weeks ago.
Was disappointing for the first 10-20 hours, but eventually loosened up.
Digs deeper now. Still need to re-tune my miniDSP, as I don't need the 20-35 Hz boost anymore.
(avatar pic shows the previous driver, mounted 'backward' for the past couple years to counter any possible driver sag)