214L Vented Tempest

[BeginnersLuck]

Hello Everyone-

I just finished construction of my 214L Vented Tempest last weekend. The total cost of this project was $337.46. This icludes all parts: wood, caulk, primer, paint, weather stripping, screws, hex-nuts, (2) 3 inch flaired port kits from PE, stuffing, binding posts and the Adire Tempest driver. This list does not include the amp...I paid $100 and some change for the PE 250W amp about 6 months ago, and that is what I'm using to power the 214L Tempest. The sub amp is in a seperate box...

This project could potentially cost less, but I wanted the best quality parts my money could get me...

I am constantnly searching for perfect bass, and while I don't think my thirst will ever be quenched, this was a great project that is worth every penny I spent. I can honestly say, I have never heard a sub that can did this low...I am thouroghly impresssed. Granted, I have not been able to hear a variety of subs (including SVS). But I am definitely satisfied until I hear (feel) something better. I was up late revisiting most of my favorite scenes and I can actually say that I have felt the "ring drop..." I know many friends who's sub cannot even come close to the performance of this sub and have easily spent 5 times as much money...I have enjoyed experimenting with DIY subs the past couple of years and I finally feel satisfied...

For music, this beast seamlessly dissapears into the room. It's abiltity to blend perfectly with my polks while still being able to deliver anything asked of it just makes me like it more and more...It brings a welcome fresh breath of air to my 2 channel listening experience with its ability to complement my mains while not overpowering them...

Well, I think I know what I have been missing all of this time...Some scenes are just downright scary, and made my heart skip a beat, it felt as if the couch was being dentonated while I was sitting on it.

So anyone interested in a DIY sub that will blow your pants off, put the 214L Vented Tempest in the Running...I highly recommend it to any one in search of sub nirvana....

If anyone has any questions, please feel free to fire away...

Later,
-BL

[tryrrthg]

Nice job! Got any pics?

I've been throwing around the idea of a DIY sub for a while but keep running into snags about how to do the crossovers for 2 channel audio, which is what I'm most worried about... I'd like to make a dual Stryke AV12 sub.

[BeginnersLuck]

Per request:

[tryrrthg]

Very nice!

Is that the truck bedliner paint/coating or does it just look bumpy in the pic?

[BeginnersLuck]

The business end of the finished product...

[Dr. Spec]

The 214 L Tempest is a DIY legend. I think with the twin 3" flared vents at 17-18" it has an Fb around 18 Hz. And with such a large Vb, the efficiency at Fb is pretty damn good and I think will be only about -3 dB at Fb anechoic (i.e., critically damped).

I have always been of the opinion that the Tempest is a bit underported with twin 3" flared vents, but for lower power applications, it seems to work just fine. Ron-P vented his sealed Tempest a few months ago with the same vent kit and has been thrilled ever since.

The Tempest is a great driver, and you cannot beat DIY for the money. The closest SVS would be the passive 20-39 CS-Plus, packing three 3" flared vents and a smaller (but much higher xMax) 12" TC Sounds dB12 woofer. The xMax of the Tempest is about 16 mm and the xMax of the dB-12 is about 26 mm. Vd for both is about 2.5 L and with similar venting, they would perform about the same. With only two vents on the Tempest DIY, it would be down a few dB on the SVS in max output. Extension for the two is very similar.

The reason it disappears in the room is the very low THD it is generating. This makes it remarkably well suited for music too, as you are finding out. A great sub can make music incredibly satisfying. Anyone who says a sub cannot be great for HT and for music hasn't heard a great sub.

Congrats, glad you are loving it! Great job! That "ring drop" is really something, isn't it? The big hit, and then the pants waffling room decay. BAAA-WOOOOOOOFFF.

Doc

[BeginnersLuck]

No, It's a black gloss paint, the bottom just looks bad becasue I rushed the bottom, no one will look at it once it's in place...

[BeginnersLuck]

I'm so excited I'm a member of the Pants Waffling Club (PWC). When do I get my mebership card?

When I first felt BAAA-WOOOOOOOFFF (as Dr. Spec so acurately describes it) of the ring drop, I thought to myself; wow, that was wierd...

Should I charge people for the experience?

Oh, yeah, if you look closely in the last pick to the top left, you can see my 122L sealed Tempest, That will be retired soon...

[tryrrthg]

Originally posted by BeginnersLuck
Oh, yeah, if you look closely in the last pick to the top left, you can see my 122L sealed Tempest, That will be retired soon...

Don't retire it! build a SECOND 214L tempest! that would move some SERIOUS air!

The sub looks GREAT! I'm jealous I can't make/afford one!

[Dr. Spec]

Yeah, vent the 122L, Fb of 25 Hz slightly underdamped with an SBB4 alignment and really pound. Or scrap it and build another 214.

OK, requirements to become a PWC member:

Must hit at least 110 dB clean (no audible distress or bottoming) on the Ring Drop at a distance of no less than 10 feet from the sub in a moderate sized HT room as measured with an RS meter or equivalent set on C-weighted Fast.

As the Charter Member of the PWC, I proudly proclaim an EASY 115 dB at 11 feet on the Ring Drop. It will play louder, but I fear structural damage.

I've already cracked drywall joints, loosened drywall panels, and creased the screen on my HDTV (will be replaced under warranty).

The PB2-Plus is a certified weapon of mass destruction in the wrong hands. Giving one to Sid would be like letting him drive a Z06 'vette; you just KNOW something would get wrecked in under 5 minutes.


Doc

[VR3]

Originally posted by Dr. Spec
The PB2-Plus is a certified weapon of mass destruction in the wrong hands. Giving one to Sid would be like letting him drive a Z06 'vette; you just KNOW something would get wrecked in under 5 minutes.


Doc

I could see siding falling off, side walls tumbling, loose nails, wallpaper peeling off (thank god) and my door falling down. Stuff falling off shelfs, broken tv, many many things. Can I have yours Doc? lol! I had to laugh when I read that.....lol :p

[Ceruleance]

with the RS meter, are you adding in the compensation factor? I'm gonna test my status on my path to the PWC this weekend. :D

[Dr. Spec]

Originally posted by Ceruleance
with the RS meter, are you adding in the compensation factor? I'm gonna test my status on my path to the PWC this weekend. :D

No correction factors allowed on the RS meter - WYSIWYG. It's gotta read 110 dB or better at >10 feet on C-Weighted Fast when the ring hits the ground. No farting, snorting, bottoming, or other signs of audible distress allowed - just clean pants waffling bass.

The Ring Drop is probably centered around 22-23 Hz, with room decay dropping into the teens (felt more than heard), so I would guesstimate the correction factor (if you were going to use one) would be approximately 5 dB on this particular passage. So 110 dB on the RS meter would be about 115 unweighted (actual) dB.

I take no responsibility for busted subs (although it would make good reading material), as entry into the coveted and exclusive PWC is purely voluntary. Are you gonna try it Sid? The M&K's got one good woof left in her.

Signed,

Dr. Spec - PWC Charter Member

[VR3]

I might although having one woofer defeats the purpose. Considering that forward woofer starts to take a grand roll off around 30-25hz where the other woofer would kick in...

[RuSsMaN]

Cool sub!

Man, I need to do *something* like that.

Cheers,
Russ

[goingganzo]

i was going to do dual tempests then i saw the av15. the av15 is just a little step up from the tempest but will cost a bit more to amplify aka 500 wats and the sub itself is about 50 bucks more than the tempest.

[Dr. Spec]

Originally posted by goingganzo
i was going to do dual tempests then i saw the av15. the av15 is just a little step up from the tempest but will cost a bit more to amplify aka 500 wats and the sub itself is about 50 bucks more than the tempest.

The AV15 is a large step up over the Tempest. xMax is about 10mm higher and xMag is 30 mm! The AV15 is almost like a mini Tumult. That woofer is very strong - probably the second best 15" driver on the market right now and a steal for the asking price.

Doc

[BeginnersLuck]

Hey Dr.-

Do you know of anyone/ head of anyone who has tried the 340L EBS vented design using the tempest driver? If so, what are there thoughts/impressions on this beast?

Thanks
-BL

[Dr. Spec]

Originally posted by BeginnersLuck
Hey Dr.-

Do you know of anyone/ head of anyone who has tried the 340L EBS vented design using the tempest driver? If so, what are there thoughts/impressions on this beast?

Thanks
-BL

No, I don't know anyone with direct experience.

I don't know what Fb is, but if it's an EBS, you can bet it's subsonic - probably 15-16 Hz. The typical EBS alignment exhibits (anechoically) a mild depression in the FR before Fb which usually fills in nicely with some real world room gain.

Overall SPL capability would be on the more sedate side compared to an SBB4 alignment, but it would troll deeper than sin and probably sound wonderful.

[BeginnersLuck]

Ok, so I have an extra tempest laying around, should I build another 214L or should I try the 340L vented EBS alignment...

Comments and suggestions welcome...
-BL

[tryrrthg]

Originally posted by BeginnersLuck
Ok, so I have an extra tempest laying around, should I build another 214L or should I try the 340L vented EBS alignment...

Comments and suggestions welcome...
-BL

I have never seen any one build that monster. I would love to see it done! if I would build a tempest and had the room for it that would be the sub I chose.

To save money you could build it in sonsub form first and see if it lives up to expectations, then make it out of wood later...

[Dr. Spec]

Originally posted by BeginnersLuck
Ok, so I have an extra tempest laying around, should I build another 214L or should I try the 340L vented EBS alignment...

Comments and suggestions welcome...
-BL

If they will be going into the same system, definitely build another 214L. Two of them side by side would blow you away. You could get a 300-400 WPC touring amp and run them both off that.

I have a perfect set-up in HT room for an IB sub, and I will build one someday. The back side of the equipment and TV wall in my HT room is easily accessible in the basement and the studs are exposed. Build a sturdy transition box, mount it between the studs, cut a hole and cover it with a grill, and slap in a few Tempests or Tumults and bammo - IB bass.

[BeginnersLuck]

Ok, so here is my next question, what is the purpose of a base plate and what are its benefits/downfalls if any?

Thanks again,
-BL

[Dr. Spec]

Originally posted by BeginnersLuck
Ok, so here is my next question, what is the purpose of a base plate and what are its benefits/downfalls if any?

Thanks again,
-BL

It holds the sub off the ground and lets the woofer freely fire downward. No more complex than that. There is no sound benefit. It is a more stable platform and much harder to tip over than post feet.