Building my first Sonotube Sub.....questions (1 Viewer)

[Ron-P]

I read thru all the sealed/ported apps. last night for the Shiva and tempest, need to read it again for the tempest. But, what is Qtc. I either read right over it, or missed it.
It looks like I will fall right into the mid Q design. Perfect.
I owe you guys all beers (or sodas) for all your help on this. Thanks
Peace Out~

 

[Kyle Richardson]

WOW!, this thread moved quickly!

Ron, these guys have steered you in a very good direction using the Tempest in a sealed enclosure. Those that don't think that a sealed enclosure can do wonders in a home theater are greatly mistaken as I have a sealed Tempest and LOVE it!

Kyle Richardson

Acoustic Visions

 

[Pete Mazz]

If the larger enclosure doesn't interfere with anything, go for it. If it does, Dan's suggestion is what I modeled in that graph, and it will be perfect for HT.
Now you have to decide if you're going to mount the amp on the tube or build a seperate little box for it and just mount speaker terminals on the sub (a lot easier).
So now, how are you going to finish it?
Pete

 

[Neil Joseph]

Ron, I am building another sonosub right now and I posted a question elsewhere about flush-mounting a plate amp to the sonosub, much like what SVS does with theirs. What method do you intend using for yours, or do you know yet?

 

[Ron-P]

Thanks again for all your help guys. Would have been lost without it.

So now, how are you going to finish it?

Most likely I am going to go with a black fabric on the sonotube and have green end caps, you know, the Green Room and all. Not exactly sure yet.
As for the amp. I doubt I will flush mount it on the sub. I was planning on building a small box for it and either having it on my flexy or mounting it to the wall just behind the sub.
The larger enclosure should work fine, so I am going that route first. If it does not, I can always modify it and add a port down the road.
After running the numbers, the Tempest mid Q design comes in at 6.16cf. If I keep my sonotube at 36", I come in at 6.37cf, not to bad.
EDIT: I read a suggestion to throw in a 15" passive radiator. What would this do?
Peace Out~

 

[Ron-P]

Word up. Just go the email that my Tempest is on its way...sorry, just a bit excited.
Peace Out~

 

[ArmenK]

Ron, a passive radiator can only be mounted vertically, so you cannot use it on a sonotube unless the tube is laying on its side. Good luck

 

[Ron-P]

Thanks Armen. Care to explain why, just so I know.
Peace Out~

 

[ColinM]

PR's can't compete with gravity.

I'm following this since I plan to build a sealed sono for a pal of mine.

Great info!

 

[Dustin B]

The mms (moving mass) of a Tempest is 195grams or just under 0.2kg. A passive radiator acts just like a port of the same diameter. You tune it buy making it weigh the same amount as the air that would be contained inside a port of the same diameter. Tuning frequency depending on how long the port is. The longer the port the lower it tunes and the more air it holds. So the more weight (to the limit the PR can handle) you put on a PR the lower it tunes. Thing is dual 15" ports have to be really long to tune low, so you can end up putting 1500+grams or 1.5kg of mass on the PRs. The suspension would sag way to much with 1.5kg on it making the PR useless. And if you made the suspension stiff enough to support 1.5kg you'd have other problems.

This is why people recommend dual PRs that oppose each other. 1.5Kg flying back and forth 20 times a second can really rock a box.

 

[Jack Gilvey]

Uh-oh, PR theory. Ron's head is gonna explode.

 

[Bryan Michael]

how much output can you get with a tempest and a pr vs a tempest in a ported box or would you get more output with dual tempest? witch would be best for ht and have the most output?

 

[Lewis Besze]

As others said PR is technicaly ported it's just "executed" differently.

The most common reason to use PR's to get away with smaller boxes,for a given tuning.Having said that large ported box may have more output but not by much,with all things equaled.

I have dual Shiva sono tuned to 20hz[12^ft] and BP 1503 with 2 Adire Pr's tuned to 15hz[5.6 ^ft],even with twice the volume[enclosure],and higher tuning the sono isn't much louder above 25hz, but the PR box handles subsonics[below 18hz] with much more ease,due to it's lower tuning.In order to tune a ported box that low you gonna end up increasing it's volume considerably,to accomodate the pipe.

I think two active driver in ported enclosure would give the most output vs 1 driver in any configurations.

 

[Ron-P]

Uh-oh, PR theory. Ron's head is gonna explode

Ok, a few more questions;
1. What is Qtc?
2. Should I brace the inside of the sonotube with 1x2's or all thread rod?
3. I will plate the bottom with legs, is there a minimum leg length I should go with?
As always, thanks.
Peace Out~

 

[Patrick Sun]

For some explanation of Qtc (look at halfway down the webpage below):
http://www.ajdesignsoftware.com/speaker/asexample.html
It can't hurt to brace the enclosure, but the beauty of the sonotube design is that you don't have to brace if the endcaps are properly attached to the tube walls. For me, bracing is just an added bit of complexity.
4" to 6" of clearance should be enough. I'd go with 6" if you use the 15" Tempest. Some will suggest 4". Either is fine, and shouldn't make a huge difference in sound quality.
Here's a couple of webpage with lots of definitions of audio T/S parameter terms:
http://myhifisite.50megs.com/tsparams.html
http://www.nightstormer.com/def.htm
T/S refers to Thiel/Small, the 2 guys chiefly responsible for the development of audio speaker design, and quantifying the parameters for use with modelling drivers and speaker enclosure systems mathematically.

 

[Jack Gilvey]

I should note I don't like that guy's explanation of Qtc from the first link:

You should note how the volume of the box(Vas) increases or decrease as you experiment with Qtc.

Of course, he doesn't mean Vas, he means Vb.

 

[Ron-P]

My questions just never end
Would it be better to run the amp into 4 ohms or 8ohms? It's 150-watts into 8 and 250-watts into 4.
Peace Out~

 

[Jack Gilvey]

4 ohms. A Tempest can be run with series voice coils (for 16-ohms), or parallel (4 ohms). You can run only one VC, for 8-ohms, but I wouldn't recommend it. That amp is best into 4 ohms.

 

[Neil Joseph]

That's how I will be wiring my dual voice coil driver as well, whenever I decide to finish the thing.

 

[Bryan Michael]

how much power shoud you use when driveing a tempest? and what amp would you recomend? and what amp non plate 2 chanel with the best price per wat of power.