Tempest sono DIY...questions from a newbie (1 Viewer)

[Jim_Lindberg]

Hey all..
After looking at a bunch of posts/links and all that jazz..
Since I am totally new to all this stuff. I guess I basically need, well, some basic question's answered. I din't see a "beginners sonotube section", I woulda posted there.
I have a 22x25' room with 8' ceilings....
I will have an Onkyo 696 receiver..
I will have the DIVA 4.1 package loudspeakers..
I will have a Pioneer SD643HD5 RPTV
I will have a sub! Just don't know what yet.
I was 1st going to get the Adire Dharman for about 600 bucks, but then looked at the forums and I wanna build my own, the cost maybe cheaper?, the satisfaction will be extreme!
So again, basic question, since I don't have any idea what I need.
I believe I want to build the Tempest with Sonotube, I would think this would be a good compliment to my other "stuff"..but, will room gain make this boomy? Do I have to use an EQ?
Is there an easy answer to what exactly size I need to build to suit my room size? I downloaded the software from Adire's site to help me out, along with the white paper. Is the design I need for my application in the white paper? Looking for the easy way out
Is anyone building the plate amp into it, and if not, where/how do you put the amp? I will be using the 250amp from the Adire site...
I am mostly looking for H/T but want good music also..
I am sure I will have a zillion more q's, but I am reading posts/links 1st trying to learn and not bother ya'll to death! Thanx so much..

 

[Dustin B]

Your room size factors more into how much output you need. If you know what kind of output you want and what size your room is you can pick a driver(s) from there.

After driver(s) are selected you then have to decide on an allignment that will meet your sound quality expectations. The favorite around here is the EBS or a near EBS design. Excellent for both music and HT. Although as Jack likes to point out, musicality really doesn't mean much. A well designed sub sounds good for both, a poorly designed sub sounds bad for both. I, like him, don't think your bass should be any less tight or controlled for HT than it is for music.

With your listed equipment and room I would highly reccommend an EBS Tempest. ~300L tuned to 16-18hz with a 6" port. It's a tried and tested allignment that has brought big grins to many members faces here.

 

[Dustin B]

Oh ya, don't know how I forgot about this, if you want to see an example of mounting a plate amp to a sonotube just follow the link in my sig.

If you don't like how that looks, or see it working with the finish you plan on, just build a simple little box to house the plate amp and put it in with your equipment rack or tuck it behind something.

 

[Jim_Lindberg]

Thanx Dustin... I have checked out your site, and like the way the amp is mounted, looks like I will be "borrowing" that design!

While I am at it...I do have the skills to build a "regular" or traditional box for the sub. So, I am now waying that option also. Which is the best way to go? Traditional or sonotube? Size is really not a problem.

And after looking at the EBS design, how does that relate to a sonotube design? Sorry for the dumb question's, but gotta know!

Using the lpscad prog, umm, has anyone come up with a way to change the numbers to inches in the actual program? hehehe... terrible I am at conversions..

Thanx again..

 

[Dustin B]

What makes an EBS design is a particular volume and tuning. That volume and tuning will vary depending on the specs of the driver. So to translate the EBS box design on Adire's site to a sonotube, you just have to figure out what length of what diameter sonotube you need to get the same net internal volume (accounting for the displacement of the port and driver).

It doesn't really matter what the sub enclosure looks like as long as it is strong and the right volume. The only exception to this is a box that has one dimension really long and the other two short. If the length of one of the dimensions gets too long it can form standing waves at frequencies in the bandwidth a sub operates.

The big differences between a MDF box and sonotube are, the sonotube doesn't require intenal bracing (therefore easier to build) and will weigh a lot less. The MDF enclosures people around here have built weigh anywhere from a bit over 100 pounds to almost 400 pounds.

 

[Patrick Sun]

W/r/t the unit conversion, unfortunately you have to use the Yankee Tool to do the small numeric value conversions to make sure you're in the metric system all the way through.

 

[Dustin B]

I personally find this tool very helpful for unit conversions.
http://www.geocities.com/f4ier/fct.htm

 

[Jim_Lindberg]

Thanx so much... I have peruved all the links here...I think that I will be ordering now! Hope to do as good as a job as ya'll have done..
What a place!

 

[Jim_Lindberg]

Well dern...
Looking again...I like what you say Dustin..and I like your site..
So to get the tune you listed in the above post...
Can you tell me the size's I need for it all??
Dustin said: "With your listed equipment and room I would highly reccommend an EBS Tempest. ~300L tuned to 16-18hz with a 6" port. It's a tried and tested allignment that has brought big grins to many members faces here."
Yeah... that's what I would like to do!!
I guess what I am looking for is the detailed info..
What size sonotube? If I use a 24" sonotube, how tall should it be?
I will be using the same endcap design as you have. 2 pieces of 3/4" MDF stacked for the top.
2 pieces of 3/4" MDF stacked on the bottom with a 1/4" piece of plywood for mounting everything.
I will be using a Tempest driver...with the AVA250 amp from adire.
Using the 6" port as you stated above, what length do I use?
And for the batting, how much do I use?
I guess it wasn't as easy as I thought plugging numbers into the lpscad!:b
Many, many thank you's to you!!!

 

[Dustin B]

This could sound a little harsh, but I don't mean it to be.

Doesn't anyone take trig or algrebra anymore? It's not very hard to figure out. I'll take some time here and walk you through it.

You want to do an EBS allignment for a Tempest. The EBS allignment in the Tempest Vented Application Notes from Adires site lists a net volume of 340L and a tuning point of 15.8hz. We'll round that 15.8 to an even 16hz.

Now in LspCad it doesn't even matter what driver you choose, all you are interested in is how long the port needs to be (which is just a function of port diameter and box volume). So pick a vented sub. Then click on the box menu option. Enter 340L for the volume. Then change the min port diameter to 15.2cm (6") and the tuning frequency to 16hz. Then read off the port length value, 50cm (19 11/16").

Now we need to figure out how long the sonotube needs to be. To do this we first need to know the gross volume we are shooting for. That would be net volume + port volume + tempest volume. I'll assume you mount the port the same as I did, in which case you take 3/4" (1.9cm) off it's length before you figure out it's volume. Volume of a cylinder is

V = pi x r^2 x H or

3.1416 x 15.2^2 x 48.1 = 34912 cm^3

Which is 35L.

So our gross volume is 340 + 35 + 5 = 380L

So we rearrange our above volume formula to find height

H = V/(pi x r^2) or

380000cm^3/(3.1416 x 30.5^2cm) = 130.03 cm

Which is 51 3/16" tall. To this length don't forget to add the length of the endcaps that will be inside the tube. In my case it was 1" on each side, so I needed to add two inches to that length.

Now this assumed that the inner port radius was actually 6" and the outer radius was the same. It also assumed the sonotube was actually 24" in diameter. The port isn't that important because the amount you will be out by won't affect the tuning any (but if your anal like me you use the actual inner diameter in LspCad and the actual outer diameter in the port volume calculation). The sonotube on the other hand could affect things. So make sure you find it's actual inner diameter before you calculate the length it should be.

To do this take a strap or belt of some sort. Wrap it around the sonotube. This is your circumfrence (C). Then

C/(3.1416 x 2) = radius

From that number subtract the thickness of your sonotube and the result will be the actual inner diameter of your sonotube. Use that in the above formulas to figure out how long it should be. I'll leave to you to use the cirumfrence bit to figure out the exact port values if you are so inclined.

 

[Jim_Lindberg]

Ah....
Sorry, my algebra days are long gone...and never needed it till now.
Again, many thanks for your comments, and the work you have done on your website..
I have it all figured out now, thanks to everyones websites on the "sonotube" link. Specially PAT's!! 130 pictures is awesome! I wonder how many folks have used that design that you don't even know about. I bet, with the detailed info, that many have taken advantage of your generosity.
Did I say, many thanks?

 

[Dustin B]

I'll just add here, mucking around with LspCAD it would seem you can be out +/- 3L and you will still be within 0.1 hz of your intended tuning. If you are +/- 9L you will still be within 0.2hz of your intended tuning.

Reguardless, all this calculation and measuring will do is get you really close to your intended tuning frequency, the only way to really know for sure is to measure it after you build the sub. However, being out 0.5hz on your tuning frequency really shouldn't affect your subs performance very much, if at all. Especially when tuned that low.

 

[Patrick Sun]

Well, Jim, you're welcomed! I'm sure I'm not the only person that influences people to try DIY, but I did my part if giving back to all the advice I got when I started out. Glad you found my page useful. I'm always impressed with the much better cosmetics that others after me have been able to add to their subs. Good luck!