Building a new Tempest Sub, need advice (1 Viewer)

[Jon_H]

Hello everyone. I think my next project over the beginning of the winter is building myself a new sub. About 2 years ago I built a sonosub with a Tempest sub, it was a dual 4" ported downfiring sub tuned to about 19hz powered by a ~150watt Soundstream M1 monoblock THX amp.
I was very pleased with the performance of this setup. Unfortunately I had to sell the sub due to the shear size of it :frowning:
I still have the amp and really want to make a new sub, I need it to be small so I was thinking of a sealed box sub. (I think a ported box sub would need to be too big, no?)
I would still like to use the tempest because I have had a great experience with adire and there products. (unless anyone else could suggest any other driver)
So pretty much m questions to get started are:
[*]Do I need to build my sub as a sealed enclosure to keep down the sheer size of the sub?[*]If I do need to build a enclosed cabinet, what size should I make it to partner with the tempest well[*]should it be downfiring (im pretty sure it should)[*]would my current amp be enough to power an sealed tempest?[*]When I plot a sealed tempest on winISD i see that it really doesnt go that low in frequency compared to a ported sonosub, can anyone make a comparison between the two, pros and cons, will I be missing much that the sealed sub wont go that low
I think thats all the questions for now, Thanks for looking at my thread!
Jon

 

[Chris Tsutsui]

I don't know a whole lot about sealed but since nobody else posted:
I'd say sealed will cut the size of the enclosure down a bit but it also cuts down the flexibility of tuning and output. As for compaing sealed vs ported, I don't see any real benefits for going sealed other than simplistic design and space saving. Bass reflex (vented) gets the added benefit of additional bass with no real drawbacks in sound quality.
Adire has three suggestions for sealed boxes that fit a lot of people's needs you can download their "tempest sealed" white papers. It depends on what kind of bass you're looking for whether punchy bass or deep and smooth. I'd say the bigger the box, the deeper it can go.
I've been hearing a lot about a linkwitz Riley type? or something rather to improve the response for small sealed boxes. I'm a vented guy myself so I havn't done much research on it but it may be something to do a search on.
I'd go downfiring as it protects the driver and stabilizes the the driver force down against the floor.
As for the 150W sound stream amp.. As much as I love sound stream power, 150W may be a bit on the low power side. My guess is you'd get a seating location SPLS of about 102db with peaks of 107db. I'd say it's a plenty for average music listening but it may struggle during demanding bass tracks on DVDs.

 

[Jack Gilvey]

Link Removed

 

[Ronnie Ferrell]

Thanks for the post Jake! I love the visuals of above, at, and below resonance! Pictures (especially animated ones) can say a thousand words!
Ronnie

 

[Jeremy Stockwell]

Jon,
You might want to consider a vented design using Adire's Shiva driver. Tempest is just Shiva's big brother. They are very similar, but Shiva is 12" and Shiva requires a much smaller enclosure, even for vented applications (e.g. 85L, 95L).
Also, if it's in your budget, look at the new Tumult driver from Adire. Looks like the best applications for this driver are Passive Radiators in small enclosures using a Linkwitz transformer. The amp that you have now won't work to drive the Tumult, however. Looks like the minimum will be several hundred watts into the Tumult.
JKS

 

[Jack Gilvey]

. Looks like the best applications for this driver are Passive Radiators in small enclosures using a Linkwitz transformer.

Not at the same time, though...those are two distinct applications.

 

[Jeremy Stockwell]

Oops! Jack, you're right. LT's are for sealed boxes. Sorry for the confusion, Jon. It would be either PR's or LT's for the Tumult. I believe that small boxes work for both applications, though.

JKS

 

[Ryan Schnacke]

I agree with Jeremy. For about the same enclosure size (around 4 ft^3) and cost you can build either a sealed Tempest or a vented Shiva.

In your particular case you won't be driving either the Tempest or the Shiva to Xmax with 150 watts. So you'd gain only 2dB by using the Tempest instead of the Shiva (89.1dB SPL vs. 87.2dB SPL). But by venting the Shiva you can gain up to 8 or 9dB at the tuning frequency over a sealed Shiva application.

I've built both a sealed and vented sub using the 12" Dayton DVC and the difference is tremendous! The extension and headroom of the vented is leaps and bounds beyond the sealed. I know this is apples and oranges compared to the Tempest. But I doubt I'll ever build another plain sealed sub. Maybe an infinite baffle or something with a Linkwitz transform.

 

[Jon_H]

Thanks for all the great input guys. Based on what I have been reading here it looks like I should stay with the vented box and use the shiva.

I think Im going to go with the 142.5L box that adire has in there plans. (p.20)

Ive never built a box sub before, only the sonosub. Does the same go with a box sub in that wood glue is enough to hold all the walls together? The adire plans call for single layer MDF on each side....should I double up the MDF on the side that the driver is on?

any suggestions of modifications that could be said about the 142.5L vented shiva plans that adire has?

thanks again all!

 

[Jon_H]

my bad, my amp is 230 watts @ 4 ohms

 

[Ryan Schnacke]

Yes, wood glue is enough to hold the joints. In fact, the glued seam will be stronger than the MDF.

Yes, I would double up on the woofer baffle. In fact I'd use 3/4 plywood as the 2nd layer on the inside. Laminating it to the MDF layer will keep it deadened and T-nuts will hold better in plywood than MDF. (I use T-nuts on the inside to hold the driver mounting screws.)

 

[Jon_H]

Well, I went to Home Depot last night and picked up my MDF. I just have a question:

The only real saw that I have to rip down the MDF is a circular saw, will this be good enough to rip it down? Will it make nice clean cuts, should I use a certain blade for it?

Thanks!

jon

 

[Jeremy Stockwell]

Jon,
I've never made a box before (I'm making a Tempest Sonotube right now), but I believe that a circular saw won't cut it (so to speak ) for the accuracy that you'll need for gapless seams.
I believe that most here would advise you to get (or borrow) a good table saw with a good strong and accurate fence to make the cuts you need for an airtight box.
JKS

 

[Dave Milne]

Jon,
Welcome to boxbuilding! Having never liked the "water heater" look, I've built many speaker boxes.

Yes, a circular saw will work. Use a sharp medium to fine-pitch blade, (preferably carbide-tipped --plain blades don't stay sharp very long).

I have a nice table saw, but I use a circular saw for the initial cut or two. Just try maneuvering a 5'x8'sheet of 1" MDF on a table saw... by yourself!

Check and adjust your saw carefully so that the blade is perfectly square to the base. You will probably want to make a few trial cuts on scrap to be sure. Don't forget the eye protection. And you may also want hearing protection... my worm-drive circular saw is pretty quiet, but my SkillSaw with straight cut gears is very loud.

Finally and most importantly, ALWAYS clamp or tack-nail a straightedge guide on the sheet before cutting. The first time you'll have to measure your saw --to know how far to put the straightedge from the desired cut --but it makes the actual cutting process fast, accurate, and safe. Freehand-circular-saw-cuts are for house framing cowboys, not cabinetmakers.

Good luck

 

[Jon_H]

Great, thanks! I just found out that I have a table saw in the basement of my house...lol...its my girlfriends brothers. Doesnt mind me using it at all.
Thanks for the advice
PS. I ended up getting the 2X4 sheets of MDF, couldn't fit the big sheet in my jeep, paid a little more in the long run, but it was easier at the time
Now I just have to fing clamps that will clamp the box together and not spend an arm and a leg ...may be able to scape some up from friends and family

 

[Jon_H]

hello, I just have another question in regards to the small harware that will be needed for this sub (142.5L shiva 4" ported)
what size bolts would I need to fasten the shiva? how many?
also T-Nuts, abviously the same size as the bolts..lol
also, is This port the same port that adite recommends in there plans? anything better?
shoud I line the sub with anything? if so what should I line it with
I was thinking of getting THESE feet for the sub. Will these spikes give me enough clearance for this sub, or is it not enough? Also, the description says that it only comes with 1" threaded studs, that wouldn;'t be enough for my 1.5" baffle....do you this I can find 2" threaded studs at home depot or a hardware store?
Thanks for helping guys and girls!
Jon

 

[Mickey Geer]

The port looks identical to the fp-4 that adire sells. As far as the spikes go, I am looking at the same set for my sonotube. I think they will work but I am no expert. Maybe someone else in the know will enlighten us.

 

[Jon_H]

Since the snow today and no work I made some progress on my 142.5L Shiva ported sub, here are some pics
Here is a shot of the dowel job Im doing on the joints (1/4" dowels)
Here is a shot of that same joint Butted together, nice flush fit
Here is a shot of the inner brace put together, (not glued yet, will glue after all dowel holes are drilled)

 

[Jon_H]

Here are some more shots on my progress today
Here is a close up of the dowel proccess
Here is a shot right before I did my first gluing, all dowels holes cut
Heres a shot of it clamped

 

[Jon_H]

anyone have any feedback
also, should I line the walls of this sub with some polyfill type stuff?
Thanks for looking!
Jon