Suppose I want to get a dedicated sub-subwoofer (for say about 10hz to about 30hz), using my current subwoofers (2 x ACI Titan XL) for about 30hz to crossover with mains (currently at 80hz).

What would be the best choices out there?

Seaton Submersive or Terraform? The new Hsu that's supposed to be flat to 10Hz? ...?

(I don't think I'm handy enough for DIY.)

FYI--the room is closed off and about 13'x17'x8'.

Thigpen Rotary!! :D

Seriously though? IB, then something like the Seaton properly set up, Custom/DIY if you're patient and know what you're doing (lots of help in the DIY forum)

You might want to consider shakers for those frequencies.

SVS 16-46+

Get duals and set them to 12hz....in room you'll get down below 10hz response...

Get the Terraform XL (if you can fit it in the room). I'm hearing talk of 8Hz. :eek:

Do you want vaguely audible 10-15hz or usable 10-15hz? Big difference.

Suppose I want to get a dedicated sub-subwoofer (for say about 10hz to about 30hz), using my current subwoofers (2 x ACI Titan XL) for about 30hz to crossover with mains (currently at 80hz).

What would be the best choices out there?

Seaton Submersive or Terraform? The new Hsu that's supposed to be flat to 10Hz? ...?

(I don't think I'm handy enough for DIY.)

FYI--the room is closed off and about 13'x17'x8'.

That's a nice, small room. Send Mark Seaton a PM, and see what he comes up with for you. Make sure you have a budget prepared, and watch what he can do. :)

Response to 10hz is certainly doable, but once you have it how much material will you actually find to play down there?

having a sub that is capable of real playback at 11Hz, I can tell you that there is plenty of great material down low. If you can swing the terraform in your room (they are very big) they are truly unbelivable. I am constantly blown away by how much power they have down low.

One thing to note is that the terraform not only goes very low but also is quite responsive, musical and quite flat from 70Hz to 11Hz.

Second for the Terraform. If that is to big, I really don't think that anybody would be disappointed with the output down low of a SubMersive.

having a sub that is capable of real playback at 11Hz, I can tell you that there is plenty of great material down low. If you can swing the terraform in your room (they are very big) they are truly unbelivable. I am constantly blown away by how much power they have down low.

One thing to note is that the terraform not only goes very low but also is quite responsive, musical and quite flat from 70Hz to 11Hz.

I have no doubt that the Terraform can hit hard way down low, but what great material are you talking about down below say 15 or 16hz? Other than a rare couple of seconds out of a small handful of movies and some test tones, what else are you listening to down there?

mojomike, you can find some VLF in this thread.
http://www.avsforum.com/avs-vb/showthread.php?t=755493

I'm aware of the list of movies with deep bass content, but I have my doubts that you or anyone without using some sort of measuring equipment, could tell the difference in the sound if a 15hz high pass filter is switched in or not. If one could tell the difference, I believe the circumstances would be extremely rare and the volume would have to be very loud. That would make for an interesting experiment.

I am willing to bet most are not going to have the output 10hz-15hz to make it noticeable.
I have decent output @ 5hz, and can not really notice it.
But it would be a fun experiment. :D

Nothing compares to the Eminent Tech TRW 17.

Nothing compares to the Eminent Tech TRW 17.

Mine woops that thing, from 10hz and up. :D But not 5hz and down. :eek:

I am not sure why you guys think that there is not enough output at 10-15Hz range to be audible or make a difference.

While I agree that many subs just throw numbers around without being able to back the claims, a few do really perform at these levels and do so quite well. That being said, there is usually a big compromise that consists of price and size of the sub to reach these levels.

In my case I have 2 terraforms which are 40"x30"x20". everyone who has heard these subs in action can attest to the results. You can ask guys like Art Sonneborn and Jeff the bland who both have amazing systems with termendous bass what they think about the output down low.

Most do not have enough output. It takes nearly 110db @10hz for me, to notice it. The minimum threshold is around 100db @10hz, and I don't feel that is noticeable. How many home theaters have over 110db @10hz at listening position? Not many. less than 5%???

Mine woops that thing, from 10hz and up. :D But not 5hz and down. :eek:

After seeing your subs I do not doubt it one bit.:)

If a movie has 10hz and 30hz material playing at the same time, you wouldn't even know the 10hz material was there....right?

I experienced the Eminent at CES a couple of years ago, and while impressive, I didn't feel it was that useful.

Yes, the house would shake a bit differently than with just the 30hz. :p

At 10hz...it wouldn't shake....that is the whole misconception. It is just feeling of pressurization, which would be overwhelmed by the shaking that the 30hz is causing.

I'm aware of the list of movies with deep bass content, but I have my doubts that you or anyone without using some sort of measuring equipment, could tell the difference in the sound if a 15hz high pass filter is switched in or not. If one could tell the difference, I believe the circumstances would be extremely rare and the volume would have to be very loud. That would make for an interesting experiment.

Hi mike,

My own experiences in making such comparisons suggests it is readily identifiable, although obviously program dependent. It is possible for cubesys to add a high pass that would do as you say. I'll have to work out the filter values for his DCX so he can play with it if he's interested.

I'm not suggesting that <16Hz is more important than 25-80Hz. I'm just saying that so long as you aren't messing up the 25-80Hz range in the process, it's a good thing to add. The device to test this with is the TRW, as it removes questions of THD and SPL capability. In the few times I have heard it, there were worthwhile contributions. While the big stomps and explosions are of course what get focused on, I feel there is more to it. A good example would be the sails flapping in Master & Commander, along with other real world, recorded events. Things tend to sound larger in scale, more powerful and more real... IMO.

What?? With a 10hz sine wave @120db, my room shakes, resonates, vibrates, whatever you want to call it.

This would make for a very interesting experiment if a 15hz filter could be blind switched.

At 120db, 10hz should be detectable, even if not heard. How many systems can actually put out 120db at 10hz?

Right...at what SPL would the 10hz need to be in order to be heard/felt over the 30hz?

How many movies call for 120dB 10hz output at reference?

10hz has a totally different feel than 30hz. It would be interesting to have a track that produced 30hz for 30 seconds, then added in a 10hz sign, to feel the combined effect. I do feel that it would be noticeable, with enough spl.

10hz has a totally different feel than 30hz. It would be interesting to have a track that produced 30hz for 30 seconds, then added in a 10hz sign, to feel the combined effect. I do feel that it would be noticeable, with enough spl.
Understood, but would you only increase the 10hz signal...or the 30hz as well?

If you are going to increase both in the same proportions, I'd say the 30hz signal will always be dominant.

At what SPL does the 10hz signal need to be for some significance?

If someone is shaking you while you rock in a rocking chair.....how much do you think you will notice the rocking vs the shaking? Does that analogy make sense? :)

A lot, if I was rocking in a rocking chair, and someone shook the chair I would notice. Another example, if you play a 20hz sine wave @110db, you can here a 1k hz sine at 70db clearly.
In your example the 30 HZ played at the same spl would most definitely be louder to the human ear, but the air movement of the 10 hz would dominate the hair blowing. lol

I am not talking about what you hear...but more so what you feel.

And again....what SPL does the 10hz need for significance?

To me, 110db minimum, @ 120db its very noticeable. And if my wife did not shut me down I could tell you what 130db felt like. :mad:

Doesn't reference level peak for the LFE channel max out at 115dB or somewhere around there?

cschang:

have you seen 100000watts setup? it's sick. I have no doubt he can generate those numbers. also, i vaguely recall Craigsub saying something similar. You need extremely high SPL in the VLF to be noticed / heard.

I don't doubt 100000watts' setup...not one bit. I am sure he can generate those numbers.

Ben and Jerry's Coconut Almond Fudge. Mmmmm. :D

Doesn't reference level peak for the LFE channel max out at 115dB or somewhere around there?
I thought that DVD's have a dynamic range of 144 db? So it would depend on how "hot" the DVD is burned to determine the maximum gain over reference?

At reference, delta of 85 db, I still clip my bass amps in some very bass intense scenes.

Excuse my ignorance...

Terraform XL subs..anybody has a picture..who makes these ?

Thank you

Excuse my ignorance...

Terraform XL subs..anybody has a picture..who makes these ?

Thank you

Mr Seaton is the man you need for that info. :D

Oh oh oh...these subs...one 18" PR and one 15" active! Oh yes. :)

They are not overly large,just what Mark ordered to get the job done. I like his designs,quality sealed or using PR's in place of classic ports.

Mark Seaton should have a website showcasing his products. I tell ya he would sell them inlarger numbers with ease. A great design needs to be known more,outside of the forum members.

I believe there is only one pair of terraforms in use right now (I can give you a hint where). the terraform XLs don't exist yet... just in Mark's mind.

Mark does have a forum where you can find more info about his designs.
http://www.websitetoolbox.com/mb/seatonsound?forum=86963

I thought that DVD's have a dynamic range of 144 db? So it would depend on how "hot" the DVD is burned to determine the maximum gain over reference?

At reference, delta of 85 db, I still clip my bass amps in some very bass intense scenes.

Here you go:

In a movie theater on the island of Utopia, with ideal hardware, any single screen channel should be capable of a clean 105 dB peak with it's own respectable bass. The LFE channel should be capable of a 115 dB peak. Drive all channels to the max and the system should be able to slam you with approximately 120 dB of bass information. Thank you Dolby

http://www.hometheaterhifi.com/volume_7_2/feature-article-misunderstood-lfe-channel-april-2000.html

Looks like you have plenty of bass!

Get duals and set them to 12hz....in room you'll get down below 10hz response...

It is highly unlikely that dual 16-46 subwoofers will generate enough of a pressure change for you to perceive that wonderful 10 hz and below response.

Having been in an room with a system incorporating 8 15" AV15's with 150 watts powering each driver (old 15" Stryke drivers) pressurizing a 3000 cubic foot enclosure, you'll know when you've hit a 10-12 hz note at an adequate level.

To hit extremely low is one thing. To do so with extremely low distortion is another thing entirely.

--Regards,

Here you go:



http://www.hometheaterhifi.com/volume_7_2/feature-article-misunderstood-lfe-channel-april-2000.html

Looks like you have plenty of bass!

I like bass, lol, and my subs are calibrated 10db "hot". I hit peaks of 130db in listening position with movies, but I run out of headroom, so I still "need" about 6 more db to make it work. :cool:

Two SVS 16-46 cannot hope to reproduce much around 10hz with high enough output,lets even forget distortion(as our hearing is very forgiving,and @ 10Hz you can have 60-70% distortion and say it is extra output !).

Two little ,tiny 12" cannot do much at 10Hz,knowing the tune is 16Hz. Plain and simple,room gain works up to a point.

Suppose I want to get a dedicated sub-subwoofer (for say about 10hz to about 30hz), using my current subwoofers (2 x ACI Titan XL) for about 30hz to crossover with mains (currently at 80hz).

What would be the best choices out there?

Seaton Submersive or Terraform? The new Hsu that's supposed to be flat to 10Hz? ...?

(I don't think I'm handy enough for DIY.)

FYI--the room is closed off and about 13'x17'x8'.

so what did you end up going with ?