[IanATC]

 Deleted because JohnR doesn't like it.

[jackman]

I've had the RAva in my system a while back and thought it sounded very good.  Probably fits into the 4 and 5 category.  Has sufficient boom for HT but is very musical and powerful.  I really liked it and know of nothing in the price range that can come close to it for musicality and build quality.  FOr $399 it's a lot of sub.  

If I was going to get a new sub, I'd take a good look at the kits from Kevin at diycable, the finished subs from Brian at Rutledge and the kits from Partsexpress.  I have a Partsexpress flat kit (subwoofer) and it's very cool.  Great deal for the money.  I'm going to put a round edge on the corners and spray it with truck bedliner.  Putting it together was a bit of a pain, made me wish I had bought the ready-built version for $50 more.  I don't think this is the same cabinet that comes with theiir sub kits.  Mine has one inch MDF and braces.  Was going to sell it but I changed my mind.
J

[Brian Bunge]

am curious how much the everest sub goes for. & i'd be interested in hearing about a plug-n-play sub w/one tumult & two 18" pr's, or a plug-n-play kit, if the price were right...

IIRC, the Everest is $2500 in passive form.  It's basically Kyle's answer to SVS' B4+.  I'd take the Everest.  He also sells a sub with a single Tumult, dual PR's and a 1000W amp.  I think it's $1900.  If you can build your own cabinet you can get the driver for $499, I think Stryke charges $125 for each of the PR's, and Madisound sells the amp for $549.  All you have to do is build a 24" external cube built with double thickness 3/4" MDF to give you 1.5" walls.

But I am not sure based on displacement that a 15" driver alone can compete with a sub that has a 12", 15" and a 15" passive radiator in a bigger cabinet. That says to me: simple physical laws of displacement.

It's not based on displacement alone.  It's based on the XBL^2 motor technology.  With most drivers on the planet you start to hear audible distortion when you really start to push them hard.  This is when you know it's time to turn it down.  As I've stated before, I actually blew one of the voice coils on my Tumult because I kept turning it up and heard absolutely NO AUDIBLE DISTORTION!  This was of course due to the fact I was running 2500W into it while watching the Pod Race scene from TPM.  

Like I said before, a single Tumult is roughly equivalent to 4 Tempests, which are pretty amazing drivers themselves.  When a single 15" driver can compare to 4 already fairly high excursion 15" drivers that says a lot.  I've seen you state how much you love your PE Titanic MK III 15" sub.  I'm sure it's an excellent driver as I've built quite a few subs with the DVC 12" and 15" subs.  Now imagine what your sub could do if the driver was capable of 3x the clean output!

BTW, fast bass is a misnomer.  Bass, by definition, is slow. If you want speed, buy a tweeter!

PORTED as I referred to it is prone to PORT noise and do not usually sound controlled enough for me.

The VMPS as I read it has no hole. It is vented via mass-loaded PR. No way to make port noise.

Additionally the mass loading makes sense. Control the Q, control the response, eliminate the boom.

Well, not exactly.  There is no port noise, but there are other issues.  In general (and I mean in general) PR subs are less accurate (higher group delay/lower transient response) than ported subs, which are less accurate than sealed subs.  A PR sub has a 5th order rolloff, ported 4th order, sealed 2nd order.  A PR based sub will actually have somewhat less "control" than if you built the exact same alignment with proper porting.  That doesn't mean they can't still sound great, but I know some folks that would take a properly ported sub over a PR'd sub any day.  

Just to give you guys some idea of the quality of bass that the Tumult is capable of I'll share with you some info. I got from a customer who bought two custom-built Tumult based subs from me.  He said they easily bested any dual Aerial Acoustics SW12's or Revel B15's that he'd heard.  He also said they were as good as, if not better than, the single Velodyne HGS-18 that he'd heard.  The rest of his music/HT system was all Aerial Acoustics speakers.

[JohnR]

Brian, were those subs sealed or PR'ed? If sealed, is a Linkwitz transform used on them?

Thanks just trying to get some more information on how people are finding these in practice. I did note your comment about distortion remaining low at high displacement.

[bubba966]

Have any Tumults been built into a front or rear firing sealed enclosure yet? Or have they all been downfiring?

I've found a front firing setup to work exceptionally well in my setup. And have been thinking about possibly going to a Tumult based setup at some point.

If I do end up with Tumults at some point, I would want them to be front (or better yet, rear) firing.

[IanATC]

I just got the overwhelming feeling this thread has in fact turned into a one-sided advert for Tumult and RAD products.

Unless the maker of VMPS would jump in and defend his products against this one-sided thread.  This time it is not one-sided due to my opinions.

[JohnR]

Brian and Kevin P are keeping the discussion at a technical level. It just so happens I've just become the Facilitator of the Lab, and I think this level of discussion is fine. If Brian Cheney would like to contribute his technical insights, that would be fine too.

[warnerwh]

One problem I see with subs other than the VMPS subs is that the Q cannot be adjusted. This alone can make all the difference in the world as sub placement and room treatments are not as critical.   This assuming that the sub can do anything you could possibly ask which I know the VMPS largers subs are quite capable of. There's no weaknesses that I can hear at any volume.  They are no less than outstanding, especially considering the price.  Driving them with a 500 watt a channel amp they are still loafing along even when it's cranked.  

I'm not saying these other subs are not capable as I've not heard them but they are certainly limited if you want the best reproduction of music possible in your room. The adjustability can make or break a sub unless it's just for watching movies.
Another problem is many people can't or won't use room treatment.  If you add the cost of extra bass traps to tune an untunable sub it gets expensive real fast.

[jackman]

I just got the overwhelming feeling this thread has in fact turned into a one-sided advert for Tumult and RAD products.

Unless the maker of VMPS would jump in and defend his products against this one-sided thread. This time it is not one-sided due to my opinions.

Frankly, this is phucking bullshite.  These guys are just responding to some misinformation and trying to add some fact to the discussion.  There ae many choices in subs and I think their contribution has been enlightening.  I don't see anything that indicates an advert.

Later,
J

[Brian Bunge]

John,

The subs were sealed, with an LT circuit, and front firing.  The customer had to place them inside cabinets and spiked into the carpet so he had to have them frontfiring.  He bought a QSC PLX3402 amp on my recommendation and has been quite happy with the setup.  If anyone uses the Tumult in a frontfiring enclosure make sure you put big, sturdy spikes on it.  You don't want them walking around the room.  BTW, I thought you'd also want to know that these were in 18" sealed cubes with 1.5" MDF walls.  The finished subs weighed 130lbs. each.

I just got the overwhelming feeling this thread has in fact turned into a one-sided advert for Tumult and RAD products.

Ian, that's interesting considering I mentioned two different products from one of my competitors, Acoustic Visions.  Doug asked how he could best the VMPS subs for somewhere around $2K.  I simply listed what I felt would do the job.  Maybe it is an advert for the Tumult, but you can buy them from any number of vendors.  You can buy them directly from Adire, from me, from Acoustic Visions and from any number of other vendors around the country and around the world.  Not once did I say, "Hey, come buy a sub from me!"

BTW, I've built subs with drivers from Stryke, Parts Express, Adire, ACI, Rythmik Audio, MCM, etc.  Of all those drivers, the Tumult is FAR AND AWAY above any of the other drivers I've used.  The Tumult is expensive, but when you compare what it would take in the way of mutiple drivers to match or best it, it's quite a bargain.

Warner,

The Marchand BASSIS unit is an adjustable LT circuit.  It allows you to not only adjust the Q, but also the Fb of the system.  You can also adjust the Q of a sealed sub by using a DVC driver with a potentiometer across one of the voice coils with the other coil connected to the amp.  Adjusting the pot changes the Q.  Also, I believe one of the Monitor Audio subs allows you to adjust the Q as well.

[warnerwh]

Brian: Thank you for the info in the Marchand Bassis unit.  I wasn't aware of it and it certainly is a much needed product.  

I looked at the design of your sub and was very impressed, especially for the money.   I'll be keeping it in mind.  Looks like the Parts Express amps with the built in parametric equalizers may also be a good idea.

[Brian Cheney]

From a standpoint of transient response a very large sealed woofer would be best.  Unfortunately this configuration provides the highest cutoff for volume.  Equalization extends the F3 at the expense of distortion and stress on the voicecoil.

The mass-loaded slot-loaded PR subbass VMPS uses is a good compromise technically while offering unique flexibility from the practical standpoint.  More than just Q is changed when you adjust the PR mass loading.  You can compensate for series R of speaker wire, output impedance of the amplifier, and placement in the listening environment.

The most frequently asked question of me at CES was "Is the subwoofer on?"  All our new 215 Subwoofer ($650) provided was high levels of clean first-and second-octave bass with a seamless transition out of a 57Hz passive filter at just 6 dB/octave with no EQ or processing.

We've done things our way for 20 years now; check our reviews for constant comment on high bass quality from owners and critics alike.

There are many ways to provide good low bass.  I like the Muse subwoofers which are as different from ours as possible.  But, they are quite expensive.  I am no friend of chuffing port noise so we do not make ported Subs. The class D and class B plate amps I have measured are the worst sounding, worst measuring amplifiers I have seen and I won't have them in my products.  Plus they fail to meet their power specs by a (generally) wide margin.

[kingdaddy]

I'll throw my hat into the ring for any of the Adire drivers in either a Sonotube or box, in any alignment.  I can't imagine even the mighty Krell master ref sub having as much clean extended low end as a Tumult, Tempest or Maelstrom driver, DIY subs IMO are far superior to any commercial design, subs are just too easy to build and the Room makes more of a difference than all the design criteria put together.  A properly designed (very easy to do) DIY sub with a good driver like the Adire models will go as low, loud and as Clean (without port noise) as any sub I've heard, now how you implement it into your Room is a whole different game, and IMO is the most important thing.  Everyone and Every Room IMO needs some kind of equalization like the Behringer Feedback Destroyer to properly integrate a sub in a room.  I'll put my Dual Maelstrom sub's up against any commercial sub and am quite confident that it will sound as good or better that any VMPS, Krell or Velodyne sub or sub's.  I'm +/-3db from 15Hz to 80Hz and these are capable of 120db in my room, and these are actual in-room measurements not published specs (which are worthless IMO) as they wont tell you what it will sound like in a real room.  Also I like the Sonotubes No Flexing and easy to build although I went a little overboard on mine because I wanted the best of both worlds (Vented for HT and Sealed for Music), plus a missile silo looking sub isn't a pretty thing in most living rooms so I used some expensive finishing techniques, but still I'm below the $2500 mark for 2 18" Maelstrom Subs thanks to Adire.  These guys will blur your vision during heavy bass scenes, and I've never bottomed them out and absolutely no port noise of any kind.

 
Here is a thread at AR that has links to pics and response graphs of the finished designed, and thanks for the help Brian and Kyle at Acoustic Visions.

http://forums.audioreview.com/showthread.php?t=1208

[Bob A (SD)]

This isn't technical at all but I'm curious if any of you folks ever had any experience with the Cerwin-Vega 189ES 18" driver that was used roughly 20+ years ago in a horn loaded configuration to provide the deep sonics for the movie Earthquake in a number of selected theaters.  Yeah I know C-V produced a lot of pedestrian stuff, but this driver garnered quite a following with both professional musicians and sound reinforcement folks in its day.

I have one in a very heavy custom downward firing ported bass reflex cabinet running with my bi-amped Magneplanar MG-IIIa speakers.  And I've owned it for over 20 years and it still satisfies -:)   As an aside if it is placed on a hardwood or stone floor the damned thing will walk as the air the speaker moves actually will lift the over 120 pound cabinet enough for it to move.  

I found an old thread on AudioAsylum that discussed the speaker:
http://www.audioasylum.com/forums/HUG/messages/40590.html

One of the posts there reflects what I remember although at a different theater.  
"I saw Earthquake at the Cinerama Dome in Hollywood, and the effect was quite a thrill. The low frequency rumble would begin during a quiet moment, then all h*ll would break loose in the movie. The LF energy was enough to really move the cement slab the seats were built on, so I'm not surprised to hear that some theatres were damaged."  

The selected theaters had about 6 horn loaded arrays featuring the 189ES drivers and most had problems with ceiling plaster being vibrated loose from the 16-18Hz rumble generated.  

Here's another quote from that thread:
"In the original setup, used for "Earthquake", a digital pseudo-random noise generator delivered low-frequency noises and rumbles that fit the waveform of the earthquake in Sylmar in 1972. These rumbles were played at 110dB to 120dB and ranged from 16Hz to 120Hz. The low end of the frequency range was limited to 16Hz because lower frequencies would damage buildings by structural resonance. (However, some theaters were still damaged.)
Two control tones, one of 25Hz and one of 35Hz, which were recorded on the print steered the noise generator. For the 1974 setup the mixing of the standard audio program into the Sensurround-speakers was triggered by 1 tone. The other one made the noise generator produce the rumbles. Variation in volume of the control tones changed the level of signals sent to the Sensurround-speakers. There's a 60dB volume increase in the main speakers when both control tones are present at the same time."

I don't have the specs other than the driver has 3" of voice coil movement , a magnet weighing over 26 pounds, and was said to be capable of generating near pain levels of SPL.  I also remember C-Vs ad campaign of the time where they plugged their professional woofers directly into AC wall sockets with no apparent damage.  And no.  I've never even considered trying THAT!  LOL

Like I said, just curious if anyone has any experience with them.

Best,

--Bob

[JohnR]

John,

The subs were sealed, with an LT circuit, and front firing.

Thanks Brian, do you happen to remember the resulting fb and Q of the LT circuit? Again, curious to know how these are being used

[JohnR]

The mass-loaded slot-loaded PR subbass VMPS uses is a good compromise technically while offering unique flexibility from the practical standpoint.

Hi Brian, thanks for your input! Would you be willing to explain the effect of the slot-loading on the PR -- I would guess it would provide some acoustic loading for the PR and thereby deepen the response... maybe?

I would also guess that having all the PR output right at floor level would enable it to load the room better - ?

Thanks

[doug s.]

...Just to give you guys some idea of the quality of bass that the Tumult is capable of I'll share with you some info. I got from a customer who bought two custom-built Tumult based subs from me. He said they easily bested any dual Aerial Acoustics SW12's or Revel B15's that he'd heard. He also said they were as good as, if not better than, the single Velodyne HGS-18 that he'd heard. The rest of his music/HT system was all Aerial Acoustics speakers.
...

here's where i am sceptical.  one of my vmps larger subs is so much better than the 18" velodyne, imo, it isn't even a contest...  this is music-only, btw, as i don't do h-t, i cannot comment on these subs for this use...

doug s.

[doug s.]

...Just to give you guys some idea of the quality of bass that the Tumult is capable of I'll share with you some info. I got from a customer who bought two custom-built Tumult based subs from me. He said they easily bested any dual Aerial Acoustics SW12's or Revel B15's that he'd heard. He also said they were as good as, if not better than, the single Velodyne HGS-18 that he'd heard. The rest of his music/HT system was all Aerial Acoustics speakers.
...

here's where i am sceptical.  one of my vmps larger subs is so much better than the 18" velodyne, imo, it isn't even a contest...  this is music-only, btw, as i don't do h-t, i cannot comment on these subs for this use...

doug s.

[Brian Bunge]

John,

IIRC, the Fb was 18Hz and Qtc=.6.  

Doug,

Skepticism is good, IMHO.  We shouldn't take everything at face value.  It's also easy to see how the Larger would easily best the HGS-18.  I'm not a fan of the servo subs that I've heard.  Something just doesn't sound right to me.

I also know of many "audiophiles" that would never consider using a bass reflex design in a music system; especially one using PR's.  I think a lot of that is due to ignorance but you know...different strokes for different folks!

[JohnR]

IIRC, the Fb was 18Hz and Qtc=.6.

Thanks Brian I've just re-opened the spreadsheets and crikey that is low, f10 of 11 Hz! I recall you said he had a large room...

Even without the LT it looks pretty good to me. f10 of 20 Hz and Q=0.6 in 3 cu ft sealed. Hits xmax and 109 db anechoic at 21 Hz.