AV-15 enclosure

[Professor.Ham.Slap]

It's been awhile, but college has finally given me a break and I'd like to start building a sonotube enclosure for my AV=15 drivers. My question is, I have no clue where to start. I know where to get the materials but I'm having trouble figuring out how exactly to tune the beast. I want it ported, so I was thinking two pieces of PVC running down from the top. The trouble is, I have no idea how long to make the ports or how to get the enclosure to the proper size... The last thing I want is for that thing to have large peaks somewhere in the spectrum. Although I do plan on adding some batting to help with resonances and what not.

Anyway, here's the specs I want to shoot for: 18-20hz tuning and size isn't really an issue.

[michael hurd]

Try messaging fabulous frankie, he has dual av15's in sonotube enclosures. Figure out the enclosure size you need in cubic feet or litres ( whatever you work in ), and add the driver displacement volume. Measure the inside diameter of the sonotube you plan on using. Take half the diameter, square it and times by 3.1415926 then you have the area. Now take the volume needed, and divide by the area to find the length you need internally. Take into account the thickness of the end caps when you are designing the enclosure and how much you are going to recess the end caps. Depending on the volume you need, you might either use 18" or 24" sonotube. If you use the 24", then you may also put the port on the bottom of the enclosure.

[Professor.Ham.Slap]

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On 1/25/2004 5:21:01 PM michael hurd wrote:

Try messaging fabulous frankie, he has dual av15's in sonotube enclosures. Figure out the enclosure size you need in cubic feet or litres ( whatever you work in ), and add the driver displacement volume. Measure the inside diameter of the sonotube you plan on using. Take half the diameter, square it and times by 3.1415926 then you have the area. Now take the volume needed, and divide by the area to find the length you need internally. Take into account the thickness of the end caps when you are designing the enclosure and how much you are going to recess the end caps. Depending on the volume you need, you might either use 18" or 24" sonotube. If you use the 24", then you may also put the port on the bottom of the enclosure.

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Thanks for the reply. I've done a lot of dabbling over at the HT forum website and I've figured out out how to do all the calculations. My problem is that I don't know how to figure out what size to make the tube. Stryke recommends 260L for a vented enclosure, but is that optimal or just a "suggested enclosure"? Sorry if I wasn't overly specific in my original question.

[fabulousfrankie]

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On 1/25/2004 3:45:14 PM Professor.Ham.Slap wrote:

It's been awhile, but college has finally given me a break and I'd like to start building a sonotube enclosure for my AV=15 drivers. My question is, I have no clue where to start. I know where to get the materials but I'm having trouble figuring out how exactly to tune the beast. I want it ported, so I was thinking two pieces of PVC running down from the top. The trouble is, I have no idea how long to make the ports or how to get the enclosure to the proper size... The last thing I want is for that thing to have large peaks somewhere in the spectrum. Although I do plan on adding some batting to help with resonances and what not.

Anyway, here's the specs I want to shoot for: 18-20hz tuning and size isn't really an issue.

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The 250L 17Hz tune is Stryke's recommended EBS alignment, this means you'll sacrifice output at higher freq's in exchange for higher output down low. With EBS you generally get better transient response as well but this comes at the lack of perceived punch(like what the RSW subs have). Designing a sub is all about trade offs and what you're willing to live with and what you're willing to lose. Each of mine are 265L(effective) tuned to 16.3Hz but thats not using the new MkII woofer which works in smaller enclosures. John Janowitz says dual 4" flared ports will work fine but since I'm kind of a nut I used a 8" Quikrete conrete tube form in each(full 4' length to get the tune I wanted). I've been thinking of taking some polyfill out and trimming the port to tune around 18-19Hz for a little more punch.

Have you played with it in a modeling program like WinISD yet(it's a free download) or is it just the dimensions part you need help with?

If you already have an alignment in mind and just need help with the dimensions this link should be everything you need:

http://www.quux.net/roo/diy/sonosub/sonocalc.html

I've double checked it's answers to make sure it's accurate.

[fabulousfrankie]

Feel free to PM me or email me at fabulousfrankie@hotmail.com if you have any design or build questions along the way.

[Professor.Ham.Slap]

Hey, thanks for all the links and help I appreciate it. I think I'm tossing around the idea of making one of them sealed and one of them ported (I have two of the drivers) to dig to around 18-20hz to get that RSW slam you mentioned (because I listened to them before and really liked the way they sound). pehaps this would get me the best of both worlds?

[fabulousfrankie]

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On 1/26/2004 5:55:55 PM Professor.Ham.Slap wrote:

Hey, thanks for all the links and help I appreciate it. I think I'm tossing around the idea of making one of them sealed and one of them ported (I have two of the drivers) to dig to around 18-20hz to get that RSW slam you mentioned (because I listened to them before and really liked the way they sound). pehaps this would get me the best of both worlds?

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I would keep both the same design, otherwise one sub will need more power to reach the same levels as the other. I'd would tune somewhere like 20-25Hz if you want punch. JJ recommended 5ft^3 tuned to 22Hz to many people, a 6" straight vent(PVC works fine) would come to 27.75" long for that alignment.