[Rob Babcock]

I got off on a tangent about huge DIY subs in the GR Circle, so as not to hijack Danny's space, I figured to discuss it here.  Has anyone here built any truly Big Ass Subs?  If so, I'm a bit curious how the thing turned out.

Some day, probably quite a ways off, I'd like to tackle the Uber Subwoofer, in search of the Mother of All Bass.  My idea would be to build two bass towers, each with 4 X Adire Shivas or 4 X Adire Tempests.  Probably sealed, too- with eight large drivers sensivity wouldn't be a big issue.  Given a large amp and some parametric EQ, cement cracking infrasonic output should be possible, no?

A question for anyone that's familiar with these drivers- would it be better to go with a single large sealed chamber or to divide the tower into separate compartments for each woofer?  I'm thinking a Qtc of .6 would serve my purposes well.  With separate chambers I could even vary the sizes & fills very slightly to round or "fatten" the sound.

And what would you choose (of the two):  Shivas or Tempests?

[bubba966]

And what would you choose (of the two): Shivas or Tempests?

Tumults. Screw the wussier Adire drivers and do it right with their top line...

[Rob Babcock]

Yeahhhh... 8 Tumults?  I'll be able to afford that- with my first Social Security check!

[lonewolfny42]

Yeahhhh... 8 Tumults?  I'll be able to afford that- with my first Social Security check!

Start saving now....then later you can buy them used.....

[denverdoc]

Forget Adire and buy from Ascendant Audio--there drivers rumble at an heretofore unheard of ratio for SPL/$$. They have not only successfully  implemented the fully lisenced Xbl^2 technology, but perhaps have taught their teacher a thing or two. I have an open style floor paln with huge amts of contiguous volume--two 18's at a swept volume of 18L max is frightening at full gain! Pice 800 usd.  Puts a velo 1812 out the door!
J

[warnerwh]

Lots of people into diy subs on the Partsexpress and Madisound forums with lots of experience into what works and what doesn't.

[Rob Babcock]

I Googled for Ascendant Audio, but although I see em discussed in forums, I don't see anywhere you can get info or purchase them.  Where would you find one?  And aren't they car woofers?

I only cited the Shiva and Tempest because they're 1) great drivers, 2) affordable, and 3) very easy to find and replaceable.  You're almost certain to be able to buy an Adire drive 10 years from now- will the same be true for the other guys?  Obviously there are several dozen good candidates, each with their strengths and weaknesses.

At any rate, it almost doesn't matter what brand.  With 8 of them any decent woofer should work.  Danny pointed out that the Shiva probably wouldn't like an alignment as damped as I suggested, but that's just a starting figure.

I've done a lot of reading on the DIY sites, and I know roughly what to expect.  I'm more just looking for any experiences you guys have with building huge subs.  My main concern is that I lack the patience & skill for finish quality woodwork, so I'd likely have the cabs built for me.

[denverdoc]

Rob,
If there is any way you can mount these IB, thats the solution--no big boxes in sight and when the killer bass tracks hit, everyone is dumbfounded as all you need is 3 sq ft or so of an opening from above as in attic, below as in basement/crawlspace or even a large closet. Of course they are killers in whatever app, but for best bass go infinite baffle,I'll post the URL in a minute,
J

[denverdoc]

http://www.ascendantaudio.com/index.htm

Terrific company and yes got their start in car audio but this a good thing, as in baptism by fire --truly ome audio with flat to 29HZ at 115 dB is a cakewalk by comparison!
J

[denverdoc]

That was meant to be 20 Hz--watching the gane.
J

[Gordy]

Here's an IB gallery, in case you haven't seen it... http://home.comcast.net/~infinitelybaffled/page2IB-Gallery.html

[Red Dragon Audio]

For an IB installation do you have to have some kind of ultra large enclosure behind the woofers or do you think I could mount them in my basement window opening so they vent to the outside of the home?

I've never considered IB applications at home but after looking at Gordy's link I'm all excited about it.

Denverdoc or Gordy tell me what you think of doing that or anyone else for that matter with experience on IB subs.

[Rob Babcock]

No chance of an IB setup.  I don't own my house and that's not going to change for at least a few years.  I don't think my landlord would go for a big hole cut in the floor into the bassment.

[Red Dragon Audio]

No chance of an IB setup.  I don't own my house and that's not going to change for at least a few years.  I don't think my landlord would go for a big hole cut in the floor into the bassment.

Just do it.

Tis better to ask forgiveness than permission.

 


Plus you can reverse that type of thing so long as it's planned right from the beginning.

Just after looking at the IB site there I want more opinions on why IB bass is the way to go.

[Rob Babcock]

This is just a hypothetical situation anyway, like I said.  Any new sub would be years away.  The pair I already have is getting me over 115 dB @ 20 hz, so I lack for nothing.  I'm just contemplating "the ultimate" sub and how I'd build it.

[Red Dragon Audio]

I'm glad you are contemplating it as it brought IB as a serious alternative to my attention.

Since I'm about to start work on my basement, I would like to find out if this is an option for me as it would be nice to not have any sub boxes actually in the room.  I don't need the window in that room as it will just be my audio/theater room anyway.  I just hope the extra bass that flies out the side of my house doesn't bother my neighbors.

[JLM]

Just install a large floor grill (tell landlord its a heat transfer grill if to the basement or the opening for a house house attic fan) and vent the drivers through it.  If you crossover low enough any adjoining neighbors will think the vibrations are coming from a nearby construction site.

What's the efficiency of those ascendents?

[denverdoc]

Careful about venting the backwave to the great outdoors. I have no personal experience in this matter, but some guys who tried it on the Cult of the Infinitely Baffled forum, say it can be very objectionable to the neighbors. Think of it as setting up a couple big drivers at the point of egress and one can easily see this is not a way to win friends. There may be some abatement measures you can take, but not sure on this point. Might try posting or searching the archives over at the cult forum to see if anyone has had success.

The basic virtue of the IB alignment is the fact that the Fs of the driver becomes the Fs of the speaker. Conventional sealed boxes will always raise this number  by a scaling factor equal to the ratio of the equivalent Vas to box volume ratio plus 1. As the box volume becomes infinite, this factor will limit to 1.

To reclaim the lost extension, guys will then usually go to a ported system, but this adds a lot of twang to the transient response so that you lose articulation. If you want low bass extension that is articulate, there is no substitute IMHO to IB except maybe going servo, folded horn, or doing one of the back assward alignments like the Bag End boys use.  Those get to be pretty big as well, and the Horn systems even in a W fold are huge: saw one at the RMAF last fall--was like 8 feet high and several feet wide. Forget pant flapping, think stomach punching, doubled over in pain impact!  For this, Horns are the alignment of choice. This from a run of the mill electrovoice driver. But stealth its not.

That is the other big virtue of IB--can be made totally so. Great to see your buddies looking in amazement as your pair of 8 inch driver based mains produced ungodly deep, fast, and tuneful bass!
Cheers,
John

[Scott F.]

I got off on a tangent about huge DIY subs in the GR Circle, so as not to hijack Danny's space, I figured to discuss it here.  Has anyone here built any truly Big Ass Subs?  If so, I'm a bit curious how the thing turned out.

Some day, probably quite a ways off, I'd like to tackle the Uber Subwoofer, in search of the Mother of All Bass.  My idea would be to build two bass towers, each with 4 X Adire Shivas or 4 X Adire Tempests.  Probably sealed, too- with eight large drivers sensivity wouldn't be a big i ...

Hiya Rob,

Just saw this thread. It just so happens I built just about the same thing you are talking about. I've got a single Shiva in a 6cf enclosure that I built into the corner of my foundation. the front baffle is 1" thick plastic.



I had planned on installing a tuned port but after I measured them, they were flat enough (in my room) that all I did was aperiodic load them. I installed 5 lbs of fiberfill and also installed a dynamat like substance behind the drivers.

Once upon a time I had the Shivas in a 9 cf enclosure but they sounded a bit tubby. In the smaller enclosure and wired to 4 ohm, this is some of the best bass that I have heard (a few of the other GAS guys agree too). They measure -2dB at about 12Hz and then they drop like a rock from there. I use an active XO and have them set at 125Hz. I'm driving them with a vintage (rebuilt) Spectro Acoustics (bipolar) amp rated at 500wpc.

I've pushed these to the point where I was physically uncomfortable just to see what they'd do. I hit 118.6 dB on big bass peaks (Rob Zombie's Sinister Urge, XO set to 750 Hz, Measured with my Sencor SP-295c). It was an absolute assult on my senses. I did bury them one time (xmax maxed out). I was playing some Nils Peter Molvear) on a House Remix of one of his songs but it was well over 110dB.

The bass is incredible. It's like nothing you'll ever experience in any standard pair of speakers. Everything in my entire house physically shakes. Pictures visably wobble on the walls. Nick nacks upstairs on our glass end tables vibrate across tops. You feel your clothes flapping with the pressure.

Bottom line.....GO FOR IT! Do what I did and corner load them. Corner loading made a huge difference in my room (it's 38' long). When they were in the 9cf enclosure I had them away from the back and side wall and I always had issues with lumpy bass. Now it's pretty darned even. Granted at different spots in the room there are some buildups but at the listening position it's pretty good.

[denverdoc]

Scott,

Nice setup!

But that's the only problem with the Shiva--can be bottomed

The SPL of two Ascendant Avalanche 18's would likely blow out the windows before bottoming. At Xmax of 3 inches p-p measured SPL by the personal report of the owner of AA is 130dB! I have no desire to repeat this experiment at home    

Like I said to Rob,  HT is a cakewalk compared to the fanatacism of the car audio dudes--did I see someone hit 170dB.   I seem to recall reading that a Saturn 5 with its 7.5 million pounds of thrust produced 150 dB (at what distance I forget) and that birds just dropped out of the air stone dead when they shot these off.