Dustin B

I think this image says it all: For those curious that's 4 ServoDrive BassTech7 bass horns and 4 SPL-TD1 arrayable loud speakers providing noise cancellation for a jet engine test. Danley's summation apperature is even more impressive than his servo drive mechanism though. Getting 4-6 direct radiating drivers and a compression tweeter to act like a point source is a pretty neat trick. http://www.servodrive.com/td1.html http://diy.cowanaudio.com/unity.html http://www.lambdacoustics.com/unity.html

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=272320 There's the thread. He wasn't saying it pressurized his whole house, he was saying it really pressurized his dedicated theater room which is very well constructed (the room doesn't let much energy escape). This is one of the prime reasons they where able to eq the system flat to something like 16hz and it's only down 10dB by 10hz. This pair of subs where capable of true reference levels in his 5200ft^3 theater even with the headroom eaten up by the EQing. Downside is they are going to be something like $3500 a piece. Also from that thread, the ContraBass will go lower, but this sub will go louder. And the BassTech7 is still king of ServoDrive output capabilities I believe.

It won't affect it. Only thing you'll have to do is rig something to prevent it from rolling.

Tumults power handling is 1600W RMS. In a smaller sealed enclosure it can use it all. In this enclosure 1000W per driver would be oodles.

Another interesting point. Just the two Tumults weigh more than most subs (96lbs).

http://www.acoustic-visions.com/everest.htm 23.5" x23.5" x48" made from 1.5" thick mdf with 3/4" bracing finished with your choice from 13 species of wood veneer, 2 Tumults, 4 18" passive radiators and weighs in just shy of 400lbs. No on board amp. Add appropriate pro amp and parametric EQ and you have one badass sub. Let me know when Kyle gets your order Ears and I'll have him email me a few pictures of it before he sends it out to you and I'll host them for you.

The differences you are hearing are not caused by the different driver orientations, but by the different allignments of the subs. If you could take each of those subs, not change the allignment but change the driver orientation you wouldn't hear a difference. Bass wavelengths are just too long for the orientation to have an effect. 100hz wave is almost 12ft, 20hz wave is almost 60ft. Unless your sub has dimensions larger than this, where you place the driver on the sub won't matter. Carpet won't absorb bass and couches will absorb a tiny amount of deep bass. Put a front firing sub behind a couch facing the wall if you want, the orientation of the driver won't affect the sound (provided there is enough space to the nearest surface, typical bass driver needs 2.5-4.5 inches). What will affect the sound is the position of the driver relative to the room. Position within the room can cause some huge swings in output (well over 10dB).

A port and a passive radiator do the exact same thing, just in different ways. The argument for usually is that a passive radiator allows for the equivalents of a large port but in a smaller box than an actual port could fit. The argument against is they don't have as good of a transient reponse as a port. Lots of good info on PRs here: http://www.stryke.com/prfaq.htm IMO passive radiators are only usefull when you can't fit sufficient porting in the enclosure you want and cost isn't a major concern. This doesn't allow using a driver designed for large enclosures to be put in a small one however. If you were going to build a 9ft^3 enclosure with the Tempest using two PRs, just keep that size and use a piece of 6" PVC pipe and tune to 16-18hz. I've built this exact allignment and am very happy with it. But if you really want, just go and follow the vented Adire Allignment. It's just over 7ft^3, but I think it's a bit under ported with only a pair of 3" flared ports. Large bass reflex Tempest don't need a lot of power. A 250W plate amp is lots of power.

Keep in mind that the PE amp has enough power to bottom the DPL12 in that allignment. So any more power is overkill. But overkill isn't always bad either.

An EBS Tempest would out gun a single HGS18. A Dharman (uses the Shiva) can keep up with an HGS15. Although dual HGS18 subs would take a single Tempest, but would also cost 8 times as much.

Different driver. The Tempest wasn't designed for small enclosures. It's purpose was great performance at a low cost, and the trade off made to meet that goal was enclosure size. You might pull off a Styrke AV15 in 5ft^3 ported. The difficulty will be fitting sufficient porting. I'd want a 6" flared port and it will be tricky to get one long enough to tune to 20hz or lower in an enclosure that is only 5ft^3. You could also do a Styrke AV15 in 5ft^3 with a pair of 18" passive radiators. This would cost a fair bit more but would give your earth shaking output to below 20hz. It would be impressive in a 20'x30' room and scarry in a 13'x13' room.

That is a rather high Q sealed allignment for the Tempest. It will have very little deep bass and not be anywhere near as defined as it could be. But it will work quite well for the type of music you are listening too. 5ft^3 is too small for a ported allignment with a Tempest. The smallest practical allignment I've seen is ~170L tune to below 20hz. I wouldn't go any smaller than the 214L Adire allignment with a vented sub. If you go for a 200L+ vented enclosure tuned to 20hz or lower you'll get a whole new experience with movies (a big low tuned Tempest is a great bottom dweller). You may not like what it does to your hip-hop bass (it will lose a lot of the punch), but the bass will be much cleaner, more defined and detailed. Not sure what to compare an over 0.8Q sealed Tempest too.

I dislike this notion that a rumble boom box makes for a good HomeTheater sub. For most music, yes a lower Q sealed enclosure that can't play the last octave can be good. But a boom box is no better for HT than it is for music. After you've heard a sub that qualifies for that most mysterious of terms, "musical", but can also shake the house down into the bottom of the last octave, you no longer have this notion that all a HT sub requires is the ability to shake things. The other interesting part of this type of sub is that it's also good for all types of music.

I'd just go with two Servo15s rather than one HGS18.

Ugh, over seas shipping for a PB2. Fire the email to SVS and get a shipping estimate (although that will probably just solidify going local for you). If both Velodyne and the Servo15 are available locally go check them out and decide for youself. The HGS18 will be able to go louder than a Servo15. HGS15 and Servo15 should be very similar output wise.

Has all, but the price is only reasonable in Canada. There are other better options IMO in the US for the same money.

I'll say it distorts, and Nousaine's measurements prove it.

Well enjoy the Sig then Ears, I know I'd never buy one. I'll take a PC+, Tumult or the Tempest based sub I do have any day, even if cost wasn't an issue.

There is no difference between front firing and down firing (if the rest of the allignment is the same). Bass wavelengths are too long. Its just that not all drivers can be used down firing (some sag too much).

Hoffman's Iron law is a ***** I now Ears, but face it, a Sunfire Sig can't compete with an Ultra. I've seen a few reviews where people preferred the original 20-39CS to a Sunfire Sig little lone an Ultra. THD rarely manifests itself without harmonics. Loads of THD down around 20hz will mean plenty of THD at 40 and 80 hz as well. There is a reason people are saying what they are about Adire's XBL^2 drivers. They produce extremely low THD levels. It does make a difference. And with the cost of a Sunfire Sig I'd much rather have Rutledge Audio or Acoustic Visions build me a slightly larger sealed Tumult (well I'd just build it myself, but for those that can't).

The Sunfire will have a hell of a time keeping up with an Ultra if THD limits are applied (especially in the last octave). The B2 is tuned to 25hz with all ports open. It isn't a bottom dweller but will provide solid output down to the low 20hz range.

Still cheap in comparison to commercial. 4 Dayton IB15 drivers and a good proamp will run you $700-$800 and nothing under $2k commercial will touch it. Also don't mistake bottoming easily as a draw back. What's happening is it now takes much less power to hit the excursion limits of the driver. The amount of air moved will determine the output level. So all that has happened is you've cut your amplification costs down considerably. For the Dayon IB15, 100W per driver would be lots. So a 2x 200W into 4 ohms proamp would be oodles of power.

I plan to eventually have one. Over on Home Theater Forum and Home Theater Talk there are three people in particular that use them who's opinion I greatly trust. ThomasW, Rich Kraus and Jack Gilvey. All three swear by the IB design and say it is the best bass they have ever experienced (and ThomasW has a lot of experience). With the Exception of Jack, he liked the sound of the dipole sub he built better in his room. But the dipole was lacking in output ability and had a bunch of other trade offs to the point that I'm sure if Jack had to choose just one he'd go with an IB too. I'm going to eventually do it (projector and new speakers have priority for me right now) and if you can, I'm very confident you won't be disappointed with the result if you go for it.

Unless you have some one local willing to demo you can't. But they do have a 30 or 45 day (can't remember which) no questions asked return policy. But you do have to risk the shipping ($30-$50 or something like that).

IMO the VTF3 is better compared to the PCi than the PC+.