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Discussion Starter · #1 ·
Okay...so I'm intrigued with playing around with a Sonotube infrasonic setup. I have a large theater (8500 ft3) space that is well treated acoustically. I have a 30" space behind my screen wall with tons of room available (23' wide). I have a Danley Labs DTS-20 in there now and I don't happen to think it looks that large. The Danley is insanely good but it does roll off around 15 hz and Danley is so booked up with military and commercial work they can't currently build any custom larger versions...so I'm thinking of building something that will extend things WAY downward in the infrasonic range. So...I'm looking at building two BIG Sonotube subs to play around with. IB design isn't practical due to access. This is what I modeled in the Sonosub program...


Two 26" Sonotube at 7 ft tall each. 4' 10" long 6" ports. 7.3 hz tune. Looking at the TC Sounds TC-2000 woofers to play with (wish they made an 18" version). I have 10 ft of ceiling height to play with so I can go another foot or two in height if there are any benefits. Seen the other thread arguments about the LMS-5400 and it seems the jury is out vs the TC-2000 so for $300 vs $1100 a pop, I figured I'd play with the TC-2000. Open to other suggestions/comments.


Can somebody model this and let me know what I'd be looking at for output and linearity up into the 40-50hz range? If I had to build 1 or two more to get the output, I'd be up for it if necessary. Distance from the subs to the first chair is about 14'...25' to the rear row. Comment/Argue away.
 

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This setup doesn't look very good. First, due to such low tuning the driver itself has to supply all the output until you get VERY low. It would hit max excursion above tuning at 11.5hz with only 400 watts of input. At this level you've only got about 103dB down in the deep infrasonics, sloping upward to 112dB at 80hz. Now, assuming there wouldn't be much signal down that low, you could probably give the sub about 700 watts to hit xmax at 20hz (you'd be hoping there wasn't enough signal lower to max out your excursion). This would give 106dB down low rising to 114. So the output levels aren't great. You'd need four of these subs at least to get any kind of real benefit from those deep freqs. In addition, you've got a 1st port resonance around 120hz, so you'd have to cross this thing very low in order to avoid problems there. Your 40-50hz would probably work.


My suggestion would be to go with the LMS-5400 instead. Give it 22cu ft of volume, a 12hz tune, and 2000 watts and it's WAY more powerful and nearly as deep as your 7.3hz TC2K design. For example, if you powered your TC2K design with 700 watts (and take a chance on overdriving it), the LMS setup would have as much or more output at every frequency above 8.3hz. At 10hz the LMS is almost 10dB stronger, and remains at least 6dB stronger at all higher frequencies. And the difference is far greater if you drive the TC2K at a safe 400 watts.


In short, this is too deep a tuning for the TC2K 15". You'd be much better off to stick with something around 14-15hz with that driver, or else move to the 18" LMS.
 

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Discussion Starter · #3 ·
Hmmm. Probably looking at a 30hz crossover point. The whole point of the exercise is to build something that will provide more output below 20hz and flat down into the single digits. If it has to be the 5400's then so be it. Only thing is...I've seen several posts that claim the TC-2000 to be every bit as good if not better in a large Sonotube design. Looking at your numbers, that certainly doesn't appear to be the case.

14 to 15hz tuning...not what I had in mind since I have pretty damned strong output down to 16hz already. Any other drivers to take a look at...that are available and don't require favors or secret handshakes to get?
 

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Assuming you don't want to install a Thigpen Rotarty Woofer or aren't into bass shakers, you would want multiple drivers to get you to spirited output levels in the single digits, in which case you'd have a sub system that would outclass your tapped horn above 15hz as well. But keeping the tapped horn and trying to build something that will excel only below 15hz using one or two conventional drivers is gonna be both difficult and wasteful, in my opinion at least.
 

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Discussion Starter · #5 ·
Actually, Ive got a bunch of Buttkicker LFE's installed in the theater. But there is nothing like excess.
Thought about the Rotary woofer but if I can get something that gets me down into the upper single digits at WAY less than $20K, and it is fun to build...then I'm for investigating it. Would like to keep the DTS-20 in the setup...it is just so freaking GOOD from the cut off point on upwards into the 80 hz range. Sigh. Maybe it is time to look into a fan...
 

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Quote:
Originally Posted by crackyflipside /forum/post/0


Or just don't fool around with taking up space for boxes and do IB.

You may be able to use some of the extra room you have and make a backspace for an IB.
 

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Lot of options. Here's another crazy idea. I'd get rid of the DTS-20 because it's just

a 12" woofer in a horn and takes up space. Free up the space and make a bass

array using $200 - $300 woofers. You have to model this to see if it's possible to implement.


A sub array tower, 7 foot tall with four 15" woofers. Then stack four of these towers next

to each other behind the screen for a total of 16 woofers. This is portable vs. making a

fixed wall of woofers. 16 woofers can do some damage. If each woofer is 86dB sensitivity,

you can get a calculated 98dB sensitivity from mutual coupling. If you wired the array for a

lower impedance or did power amp distribution, you can get more sensitivity, maybe up to

104dB or higher depending on how nuts you go.
Look into ported or sealed LT

and choose the power amplifiers wisely. I wouldn't spend $20k on a fan woofer.
 

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Discussion Starter · #13 ·

Quote:
Originally Posted by thylantyr /forum/post/0


Lot of options. Here's another crazy idea. I'd get rid of the DTS-20 because it's just

a 12" woofer in a horn and takes up space. Free up the space and make a bass

array using $200 - $300 woofers. You have to model this to see if it's possible to implement.


A sub array tower, 7 foot tall with four 15" woofers. Then stack four of these towers next

to each other behind the screen for a total of 16 woofers. This is portable vs. making a

fixed wall of woofers. 16 woofers can do some damage. If each woofer is 86dB sensitivity,

you can get a calculated 98dB sensitivity from mutual coupling. If you wired the array for a

lower impedance or did power amp distribution, you can get more sensitivity, maybe up to

104dB or higher depending on how nuts you go.
Look into ported or sealed LT

and choose the power amplifiers wisely. I wouldn't spend $20k on a fan woofer.

Well, that "just a 12 woofer in a horn" is giving me more output down into the range below 20 hz than I could ever possibly or sanely use and has an absolutely unreal sound quality to it, particularly in the mid bass region from 30 to 80hz that I seriously doubt I could duplicate. Hey, I'm the first person to admit that when it comes to designing a subwoofer I am NOT Tom Danley.

The only reason to consider doing something like this is to extend the LFE down below 15hz down into the single digits just for the sake of sheer excess.


IB isn't a consideration at this point...it would require a restructure of the ceiling above the screen wall...no can do.
 

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if you have the space for an IB, there is no better option. Multiple drivers in an IB, and you got what you are after.


edit-oops, I just saw your comment of IB not being viable. "doh!"
 

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Quote:
Originally Posted by Soundood /forum/post/0


Well, that "just a 12 woofer in a horn" is giving me more output down into the range below 20 hz than I could ever possibly or sanely use

If the DTS-20 is that impressive to you, then you probably will find satisfaction

with the text book 'EBS' sonosub design using a $300 woofer and $300 amplifier.

You can make one and try it out. If you are happy, then sweet. Your quest

completed. But if the sub is not outputing as much as you want, then build

another. figure out how many EBS subs can fit in the room so you can figure

out what the upgrade path is -- just in case -- you need a few more.

[DTS-20] has an absolutely unreal sound quality to it


/joke


Why is the DTS-20 good if the sound is un real ? Don't you want

real sound instead ?



/end joke

particularly in the mid bass region from 30 to 80hz that I seriously doubt I could duplicate.


Bass horns have than effect on people. They output strong bass and midbass.

The DTS-20 isn't the only design that can do this. A text box bass horn will

do the same thing. Problem is that most people don't know how to build them,

but if you look hard, you can learn how. It's a more advanced DIY project.


The bass array using lower cost woofers can do the job of sonosub + bass horn

mainly because you are using alot of woofers, the more you use, the easier

it is to hit the goal.
 

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Discussion Starter · #16 ·
Yeah, I thought I'd try it out. Thing is, if I'm going to take the time to build a sub or two...or four...I'd want to build something that did go stupid deep. If I am going to do it and take the time...I'd do it once and do it right. That is the problem with running two companies...time is limited.


The DTS-20 does output strong bass...but it is the quality of the sound that is going to be hard to give up. It is just so freaking *right*. As mentioned before, I'd have them build a bigger version but they are just flat out too booked up and I have the urge.


Height and depth aren't much of a restriction. Guess the question is...what freestanding sub design (drivers, etc) will give me the deepest possible extension down into the single digits with the output I need, keeping within a size range of say... 5 ft wide by 8 foot tall by 2 1/2' deep. If I did two towers at 2 1/2 wide each, could use four if necessary. SonoTubes sound enticing but I'm open to other suggestions.

I am a Behringer Dealer so EP-2500's are available and I do Crown and QSC as well.
 

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Discussion Starter · #17 ·
One other thing...

Please spec vented vs. Sealed!
 

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Make one ported sonosub using the $300 woofer. Tune it to whatever makes you happy

and then install it and try it out. This wlll keep the project budget lean and you can check

performance to see if the output is sufficient and if not, just build a few more until it

reaches 'stupid deep' output that you want. One sonosub should tell you alot about

how two, three or four will perform. Worst case, if you think extra sonosubs won't work

based on the performance of the *one*, you can sell it to someone to get some cash

back, perhaps even profit. Then re-evaluate your plan again but this time you have

performance data to help you figure out what you really need.
 

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Now, this is the perfect app for the big dog 18" TC 5400 driver. And, the TC2K won't come close on any conceivable level.


I fits in a very small box. Build 4 boxes with 2 sets (4) of opposing drivers in each and power it with serious juice and you will indeed have 'stupid deep' (loved that).



I honestly would build 1/2 of that (8 drivers), powered by 20KW, L/T and go from there.


I also agree that if you did build a system like this it would so dominate the tower of power.



Bosso
 

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Discussion Starter · #20 ·
Hmmm. 8 drivers at $1200 a pop...plus wood...that adds up to...hmmm. At that point I am probably getting into dealer cost territory for a fan from hell setup and as good as the 5400's are...I'm just not sure I can get 1hz response from it. Heck, I'd probably settle for a meager 8 hz



Damn...I just WISH Danley had some time! I know they are capable of building something that would do it...a DTS-60 or some such. Maybe I'll try doing one or two of the smaller LLT sonotube subs. Worse comes to worse...it could go in my office as my computer sub (now THAT would be amusing!). Any other multi-driver ideas that won't run $10G's? I'm still open to suggestions/insanity.
 
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