15" Avalanche enclosure recommendations

[Dotay]

I just purchased a 15" Avalanche on special and I'm trying to figure out what enclosure I should put it in. I will be using this sub for 75/25 HT to Music but I don't want the music to suffer. Generally speaking I like the sound of a sealed enclosure but then again I've never heard a really well designed ported system.

The listening room in my apartment is ~15'X12' with an 8' ceiling. The room does however open up into the rest of the apartment on both sides so the total volume of space is about twice that maybe.

I was thinking of trying for a small sealed sonotube and try to stick to the recommended 2.2 cu/ft that I've seen posted on AA's website. By my calculations that would give me a sonotube that is 15" tall with a 18" diameter. This seems like it's pretty small to me which isn't a bad thing (actually a pretty good thing :T )but I just wanted to make sure my calculations were correct.

I was planning on driving it with a Behringer EP-1500 that puts out a claimed 1200 W at 4ohms bridged. I am also planning on getting a Behringer DSP1124P to help equalize the sub since I'd like it to still go real low for HT duties and room placement will be somewhat limited.

So I guess what I'm looking for is feedback on what I've got planned so far and possible alternatives. My main areas of concern are:

--Is this amp overkill for my application? If so what would be a better amp of choice in the under $250 category. Fan noise isn't a huge concern because I'm planning on replacing the fans with quieter ones like outlined on the cult website.

--Will the sub play low enough for HT if I can equalize it with the BFD?

--Is the sonotube construction ok in a small sealed configuration? Most of the sonotubes I've seen are big ported designs. I like the idea of a sonotube because of ease of assembly and it'll be pretty cheap to build.

--I don't know how to use any of the modeling software so I'm not sure what kind of response I would get given what I'm currently planning. So if someone would like to model it up for me that'd be great.:B

--Is there another enclosure that I should consider that will meet my needs more than what I'm considering now?

I'm also trying to decide how I'll end up finishing the sonotube. I really like the finish on Andrew Pratt's Tumult sub with the Velveteen fabric but I was also thinking of maybe doing something like a brushed metal look (but maybe that's better tackled in post more specific to finishing).



So let me have it. :wink: :B

[cjd]

Personally, I would go with a little larger than minimum sealed enclosure. Toss about 1000W at it in up to 3cu/ft sealed, add EQ, and pad your jaw when you crank it so it doesn't hurt when it hits the floor. So, your amp is ideal.



21.5x21.5x24 or something like that.

My uncle (among others) was over when I delivered this to my dad. We fired up the "shoot the walls to bits" scene in "The Matrix" and CRANKED it. Watching the driver dance was absolutely crazy. The fact that it moves THAT much without troubles is insane. Rocked the house.

(This one is a Tumult. The Avalanche 15 is a drop-in in this box.)

Sonotube should be fine, but I'm not a fan of down (or up) firing setups.

C

[Captain Cojo]

I just ordered 2...any way of incorporating these with the rs 3-way? Pick up mdf tomorrow, drivers came today (180-270)

[cjd]

Do you want them to be basically in the same tower?

Since these could comfortably cross at 50-70Hz to the RS270's I think it would be quite reasonable to do a side-firing setup. I can think of a few ways to incorporate all four drivers (AVA15's, 270's, 180's, 28A) into one enclosure quite nicely if we go with the side-firing setup.

You like it loud, right? :B

What amp(s) are you using for the subs? How will they be crossed? I'm assuming some kind of active setup...

C

[Captain Cojo]

I dont have a sub amp in mind-active is good. Suggestions? Remember-I can go 24 " wide if need be. I just want them to be show stoppers! Im not looking to cut corners, either.

[Captain Cojo]

And yes...incorporated in the same tower is what I would want to do. Mabey start a new thread? :roll:

[cjd]

Why not your existing thread? I mean, it's on topic still for that one

Gotta do some research on the best way to cross. Custom active filters may be the way to go, but then maybe not. Someting like an Outlaw ICBM may do the trick quite nicely but I don't remember if that does stereo subs.

Adire's ADA1200 plate amp is excellent, but doesn't do speaker level (nor do I think you'd really want to do speaker level). So any crossing really should be prior to the speakers.

Amp-wise, pro-amps get you the power clean and at a reasonable price.

C

[Dotay]

Hmmm...the only reason I'd be hesitant to go with a bigger enclosure is because of the review I saw that compared the Avalanche 15 with the Tumult. In that review the guy seemed to think the Avalanche was better suited in a small enclosure.

Anyone care to run the numbers and see what the difference between 2.2 and 3.0 cu/ft would be?

[JonMarsh]

With a sealed box and Linkwitz transform, you can get any FR you want (within reason), but the smaller the box, the more power it takes at the bottom end. The Avalanche 15 has enough motor in proportion to the cone to go that way well, whereas the 18 really likes a bigger enclosure- . What I usually do is graph the power curve in Unibox, and chose an enclosure size that I can just high Xmax with using the available power. That's the SMALLEST box you can get away with, for full output. Other's might reasonably sugggest using a larger enclosure, less EQ, and not be pushing the amplifier or the voice coil as hard theremally. I usually shoot for a sealed box Q of 0.5, critically damped, and can use a very simple shelving EQ. That's my preference in my own systems- it depends on how badly you want to minimize the enclosure size.

Remember, that reveiw was done with enclosures with NO EQ. and note there were NO measurements published, because he lost them.... dog ate my homework. I don't dispute his subjective impressions, but there's a lot of "science" that goes into this, and you shouldn't overlook that. Remember, the sub type that most everyone raves over when they've heard it is an IB sub, which in essence is a very LARGE sealed enclosure, with driver operating near free air Fs.

~Jon

[JoshK]

I bought one of the AV15 too and had been thinking of doing a large sealed box. Monte Kay, has a 15" Bully sub in a large sealed box and mentions that it is basically (according to Small definition) an IB. I am sure it isn't the same as going in the attic, but I don't have an attic.

I basically know nothing about subs, and this will be my first but MK's idea seemed doable to me. Any suggestions?

[JonMarsh]

It's quite doable- but again, if you go with a Q of 0.5 or so, you'll be in the territory you want. Do you have a relatively late model of Excel? Then you can set up the driver parameters for what ever subwoofer you're interested in, and see what it will take.

~Jon

[JoshK]

yeah, I'm a financial analyst (quant research) so I definitely have excel.

I'd appreciate it. I guess I need to d/l and familiarize myself with a modeling program.

[Dotay]

I downloaded Unibox but I'm not really sure what to put in for absorption and leakage. I put in a Q of .5 and did the auto optimise like you suggested Jon and this is what I came up with.

Image not available

This looks pretty good to me but then again I don't know if it's setup properly.

By my calculations this would be around 33 inches for an 18" sonotube so I think I'll try to turn it into an end table of some sort.

[JoshK]

For those that want to do a sonotube, I saw a guy on diyaudio nest a 12" tube (for 12" sub) inside a larger tube (18" maybe) so that the height of the sonotube wasn't too tall. He was building it for a MLTL enclosure but I think you could do something similar for whatever else you wanted to do with the enclosure. Pretty ingenius idea I thought.

[JonMarsh]

You can play with the input power than cross check to the Excursion graphs and see what it takes to just nudge you up to the Xmax. Larger box will take less power, but at a Q of 0.5, you should be in pretty comfortable territory, anyway.

Then try setting up for a box Q of 0.7 or so- you'll see the low end fall off, and you can still get it up to Xmax and max output, but it will take more power...


~Jon

[Dotay]

OK, I've decided to go with a 24" X 18" (~ 100L) diameter sealed sonotube. Using unibox this gets me a Q of .547 Now this isn't right at the Q of .5 that Jon had recommended but it was a compromise based on a few different criteria. I was able to buy a pre-cut section of 24" X 18" Sonotube for $9 where as I would have had to pay $65 for a full 12' of 20" sonotube. I want to stay at or around 28" total height with legs and end caps because I will be using the sub as an end table. Also I want to wrap the tube with silver laminate from parts express and it is only 24" wide.

I also bought the Behringer EP1500 amp which puts out 1200 Watts at 4 Ohms so I should have plenty of power and I also plan to buy the Behringer DSP1124P to equalize the sub to play flat really low.

So does anyone see any glaring problems with my thought process here? I haven't actually started construction yet so now would be the time to change anything if I needed to.

I am gathering up some parts to finish off the sub and I was hoping to get some input on which binding posts to use. Will these cheap ones from parts express be adequate or should I spend a little extra cash to get something better?

What is the best way to connect the BFD with my receiver's RCA sub out? I read that the BFD takes either balanced XLR inputs or a balanced or unbalanced ¼" jack so I'm guessing I'd need some sort of converter. Is one of these connectors better than the other? Should I use XLR between the BFD and the amp?

Finally, I'm not 100% set on that vinyl laminate that I said I had planned on using. Ideally I'd like to wrap the tube in a thin sheet of brushed stainless steel but that'll cost a bunch and I'm afraid it'll dent too easily. Are there any other good laminates that look close to brushed metal?

[ThomasW]

The surface of the tube isn't smooth so anything thin used as a veneer will show the wrapping underneath. Carpet or fabric with a thick nap is the best choice IMO.

This is covered with car headliner material



This is a short loop carpet



These two links will get you started with the BFD

http://web.archive.org/web/20030201100845/www27.brinkster.com/jmag999/

http://www.snapbug.ws/bfd.htm

And if you scroll down a ways on the link below, I put info about the Behringer on the FAQ page for IB subs

https://web.archive.org/web/20151002110942/http://home.comcast.net/~infinitelybaffled/page3IB-IBmanifold.html

[Dotay]

That's a bummer about the laminate being too thin. I don't really want carpet so I might try the laminate and see how it looks. My tube doesn't seem too rough on the outside but I'm sure you're probably right that it'll show through. I'll give it a shot and see how it looks. If I don't like it I can always come up with a different finishing option.

Is it generally a better idea to do a circular base plate like the subs you posted Thomas or go with a spike set to couple the sub with the floor. My apartment is carpeted with concrete floor underneath if that matters.

As far as endcaps go I was thinking about using 24" round granite for the top endcap, 3/4 plywood for the inner caps, and 3/4 MDF for the bottom cap. What would be the best way of attaching the granite to the plywood? Would just basic wood glue work? Should I use T-nuts or will I be ok just screwing directly into the plywood?

I read somewhere about people using threaded rods to attach the endcaps together. Is there any real benefit to doing this?

How much polyfill should I use for my given enclosure size? Is there a particular brand that I should be using or will normal pillow stuffing work? Is there a specific material that is "better" than others?

Thanks for helping out a newb, I'm really looking forward to starting the building process.

[ThomasW]

Curving a high pressure laminate will result in stresses at the seam. Unless you have some form of mechanical barrier or fastener at the seam, the laminate will try and lift. Also it's really no fun trying to match up the ends of the laminate where they come together at the seam.

There is no benefit to using metal rods.

Sealed subs are stuffed 'to taste' at a rate of 0.5 to 1.5 lbs/cu ft.

Fiberglass is actually better than poly for damping subs. There's no difference between brands of standard poly

What would be the best way of attaching the granite to the plywood? Would just basic wood glue work?

Use epoxy

Should I use T-nuts or will I be ok just screwing directly into the plywood?

I always use T-nuts, since I take the driver in and out multiple times when fine-tuning the amount of damping material.

Edit: I misunderstood when you stated the dimensions of the tube, I thought you were using tube 18" in diameter. It's really better to have an enclosure thats deeper than it is wide. With only 18" of depth you're potentially going to have issues with the rearwave off the woofer bouncing off the rear endcap and coming forward.

[Dotay]

Edit: I misunderstood when you stated the dimensions of the tube, I thought you were using tube 18" in diameter. It's really better to have an enclosure thats deeper than it is wide. With only 18" of depth you're potentially going to have issues with the rearwave off the woofer bouncing off the rear endcap and coming forward.

The diameter of the tube is 18" and is 24" high. The smallest piece of round granite I've been able to find is 24" in diameter so that will be on top of the sub. Sorry for the confusion.

What are your thoughts on using a base plate or spikes for the feet?

[ThomasW]

I build the two subs in the pictures above, that should give you some info about my thoughts on base plates ...:wink:

[Dotay]

I am getting ready to start making sawdust but I had a few questions I'd like to get some feedback on before I start.

I am planning on making my end caps similar to this.



My question is whether or not I should simply use 1.5" endcaps as I had planned or go with a beefier cap like shown in the tubzilla page. I'm planning on recessing the driver if that makes much of a difference. My main cosideration for not doing this is that it would chew up space for the internal volume but I'm not sure if that is a huge concern since I'm going to be sealed and powering with a Behringer EP1500 so power shouldn't be an issue.

I am also scrapping the idea of having a granite top because it was going to be too flippin expensive. I think what I'm going to do now is some sort of hard wood with a translucent black stain. I have yet to purchase this wood but I'd guess that it's going to be anywhere between .75-1". I guess I have the same question for the top end cap. One layer or two of mdf in addition to the hardwood.

Also, I have a question about my use of T-nuts to attach the sub. I have read somewhere where ThomasW said t-nuts don't work very well when going into MDF and he suggested using some sort of other wood inserts. I'm a bit confused by this so if you could clarify I'd appreciate it. I'm going to have access to plenty of scrap plywood so is it simply sandwiching the plywood between the layers of the MDF or is it something else. Pictures would obviously be a huge help in the department.

Lastly (for now at least ) I'm trying to decide whether or not to use the rubber stripping that comes with the driver or if removing it would be better. This is obviously going to be effecting my driver cut out dimension so I'd like to here pros and cons to removing and leaving it in.

I'm really looking forward to getting this thing completed. Thanks.

[ThomasW]

In that example the actual end cap is 3 layers of 3/4" material. Doing that enables the driver to be recessed and still have a 1.5" thick end cap. Recessing the driver makes it easier to get a good airtight seal and helps protect the suspension and cone. Note that the bottom layer of the end cap is outside the tube, and overlaps the sides to provide a hard edge for the carpeting.

The bottom plate in that pic is 2" bigger in diameter than the end caps. Doing that helps balance the 'look' of the design and makes the base wider = less tippy

Personally I don't use the rubber trim rings, I occasionally have problems getting a airtight seal with them in place.

I always use T-nuts with sealed subs since I'm fiddling with the amount of damping to fine-tune the performance. Sometimes I don't use T-nuts with ported designs since it's very rare to open them up.

If I use T-nuts, I either use ply as the inner layer for the end caps, or I glue pieces of real wood to hold the T-nuts.

[Dotay]

Thanks for the reply Thomas. OK, I think I finally figured out why was having trouble picturing where you would glue pieces of wood to attach the t-nuts. I had always envisioned using the t-nuts on the outside of the end cap instead of on the inside. :banghead: I've heard t-nuts can be troublesome to work with, do you have any good ease of use suggestions based on your past experience?

I definitely like the design of that end cap and I'm going to be mimicking it fairly closeley. The only thing left to decide is whether or not to use 2 layers of 3/4 for the recessed parts of the caps or just leave it at 1 layer. What would be your suggestion Thomas?

[ThomasW]

My suggestion is copy the design in the picture.

The only other tip for t-nuts is to put a dab of hot glue on them to keep them in place.

[Dotay]

OK, I am finally making some progress on my enclosure so I figured I would post some pics to give anyone who might be interested an update. Full size versions are linked.

This is showing one of the cutouts for one of the interior pieces which incidently ended up becoming scrap...read below.

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This is my first experience doing any routing and just a little FYI...the Jasper Jig measures to the outside of a 1/4" bit and not the inside, Doh! ops: This brought about a valuable lesson learned, if you are unsure about the cut make a very shallow cut and measure. I also found out that because of this my brand spanking new fancy jig was too small to do any of my cuts. :M So I actually ended up drilling some new holes in the jig to make my 18" diameter circle.

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Because my Jig was too small to make an 18" circle it was much to small to make a 19" circle so I prototyped and fabricated a super high tech jig (feel free to place orders of 100 units or more).

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I made the small holes the same size as the pin for the Jasper Jig so my jigs are interchangeable. :T

This is the cut for the recess of my driver. This is using a 3/4" flat bit and I was able to get the perfect (IMO) outer edge of 15 3/8" by using the 14 15/16" hole. The recess is 3/8" deep.
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My inner driver cutout was made using the 1/4" upcut spiral bit and it comes in right at 14". I need to trim this very slightly because the driver hits on a small angled portion of the on the underside of the driver. Once I trim this I think I'll have a perfect flush fit.

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Here is a test fitting on the tube.

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I've got all of the pieces cut except for the two bottom plate pieces (should be easy) and the top piece which I am planning on making out of some sort of hardwood (don't have this yet).

I do have a couple quick questions though...what would be the best way to attach the pegs to my baffle and then to the bottom plate? My main concern is being able to remove it fairly easily so I can add stuffing through the driver hole. I was thinking about maybe putting some t-nuts on the baffle and putting a bolt on the end of pegs (not sure how I'll do this, maybe a t-nut on both the peg and the baffle and use a threaded rod to connect them.) I would then probably just use some sort of screws up through the bottom of the plate to attach the bottom of the pegs to the bottom plate.

The suggested round over bit I bought from this thread was 3/4" and although I haven't used it yet I think it might be a little too big for my purposes. What will a 3/4" roundover do to a single sheet of 3/4" mdf? I kind of wanted to round over the edge of my baffle that faces down but I think the bit might be too big. I also had planned on rounding over my top piece which will probably be 3/4" - 1" and the top and the bottom of my sandwiched pieces that make up my bottom base plate. I don't think i really want the roundover to take up the entire end of each piece which is what I'm envisioning happening if I use this bit.

[ThomasW]

I do have a couple quick questions though...what would be the best way to attach the pegs to my baffle and then to the bottom plate?

I used 3.5" long deck screws. If you look at the pictures I have posted you can see the heads of the screws.

What will a 3/4" roundover do to a single sheet of 3/4" mdf?

Depends on how far down you lower it onto the board. Take some scrap and try different cutting depths.

[BlakeN]

I could be way off base here but I think your using your jasper jig upside down. It sounds crazy but my jasper has the numbers face down when you use it. The way your using it the backing with the numbers will rub off after a few uses and you can't see all the numbers for the holes. You put it on the other way so you can see all the numbers when your looking at the bottom. You then stick the pin in and flip it all over ontop of you guide hole. The pin will stay in. If you look at the close up of your pin picture it looks like you cracked the plastic by forcing it in.

Go here and look at the picture for the model 200
http://home.flash.net/~jaspera/ you can see that its put on the other way.

I think its a common mistake when using the jasper jig. The instructions that come with it are absolutley terrible.

[Dotay]

I could be way off base here but I think your using your jasper jig upside down. It sounds crazy but my jasper has the numbers face down when you use it. The way your using it the backing with the numbers will rub off after a few uses and you can't see all the numbers for the holes. You put it on the other way so you can see all the numbers when your looking at the bottom. You then stick the pin in and flip it all over ontop of you guide hole. The pin will stay in. If you look at the close up of your pin picture it looks like you cracked the plastic by forcing it in.

Go here and look at the picture for the model 200
http://home.flash.net/~jaspera/ you can see that its put on the other way.

I think its a common mistake when using the jasper jig. The instructions that come with it are absolutley terrible.

It's not cracked it just has some scratches on it. I think you're right about using it upside down though because some of the paint that is close to where the router attaches has started to come off. I also agree about the retched directions, not much help especially for a newb like myself.

[BlakeN]

I am glad its not cracked. Those things are expensive for glorified plexi. They are great at what they do but still a bit over priced. I have been looking for a vendor selling the 300 cheap but havent found one yet.

[Dotay]

I have the sub all put together now but I still have to do some finishing touches. Left on the to do list is the following:

Roundover the base plate and the baffle plate edges
Cut my tube so it's good and level on the bottom
Cover the outside of the tube with the vinyl I bought (hopefully this will look ok, otherwise I'll have to come up with a better solution)
Paint the baseplate/pegs/baffle with the truck bed liner
Buy/cut/finish a good piece of hardwood for the top of the sub so it looks like a more finished piece of furniture
Caulk all of the interior seams
Do some testing to see how much fill I need to add/subtract

Here are some pics of where I am now.

I'm really not sure how much of this fiberglass insulation I need as I'm not quite sure how I can can measure how much it weighs. Is there anything special I need to do to secure this filling or can it just sit in there loose? Will it be a problem if the insulation is resting on the back of the magnet?

Images not available

I am having some issues with my EP1500 so right now I'm powering it through my little Dayton 10 incher's 100 watt amp and this thing is amazing even with only 100 watts. I can't wait until I can crank full power through it. :twisted:

[ThomasW]

Looks like progress to me ...... :B

Damping is added at a rate of 0.5-1.5lbs/cu ft.

Start with 1.0lb/cu ft.

I increase the amount in 1/4lb increments and keep adding until the bass stops tightening and the only effect is the overall output dropping. At that point I remove the last amount added.

[Dotay]

Looks like progress to me ...... :B

Damping is added at a rate of 0.5-1.5lbs/cu ft.

Start with 1.0lb/cu ft.

I increase the amount in 1/4lb increments and keep adding until the bass stops tightening and the only effect is the overall output dropping. At that point I remove the last amount added.

Do you actually weigh the stuffing or is it more of a guestimate? If you do weigh it how? Does it matter if the stuffing touhes the magnet? Should I line the interior walls with anything or is the fiberglass stuffing sufficient?

[ThomasW]

I use a kitchen scale. My questimations aren't very accurate...:wink:

[Dotay]

One more question...for now that is.

Do I need to use small tacks or anything to attach the tube to my end caps or would simply glueing and then caulking at the seems be sufficient?

[ThomasW]

I use a brad nailer to 'tack' the endcaps in place while the adhesive dries.

And I use a siliconized acrylic caulk for both the 'glue' and caulk, since it easily cleans up with H2O. One could certainly use liquid nails for this...

[Dotay]

This is covered with car headliner material

I am rethinking my covering options for this sub. Where did you purchase this headliner material or do you know of anything that would look similar?

[ThomasW]

His wife purchased it at JoAnn's a local fabric/cloth store.

You should be able to find it at a car place that does reupholstery

IMO it looks better in the picture than it did in real life.

The carpet on Tube-Zilla looks better in person (so I'm told by those seeing it)

[JonMarsh]

His wife purchased it at JoAnn's a local fabric/cloth store.

You should be able to find it at a car place that does reupholstery

IMO it looks better in the picture than it did in real life.

The carpet on Tube-Zilla looks better in person (so I'm told by those seeing it)

I agree. ThomasW's carpeted Tubezilla has often made me wonder how I couild sneek it as carry on baggage when coming home from Denver...

[Dotay]

I finally got around to sealing up both end caps this weekend and I took a few measurements. I took these measurements with my RS meter (corrected) using some sine waves I downloaded online. I still need to get room EQ wizard up and running and setup my BFD. Oh and actually cover the tube, paint the endcaps, and finish the top as well...I'm getting closer at least. ops:

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Measurements were taken with a 200Hz crossover setting and my mains turned off.

It feels good to have it actually finished...well kind of. Stay tuned for actual finished pictures hopefully within the next year. :lol:

[ThomasW]

Well you posted good news and not so good news.....that listening position plot needs some help....

[Dotay]

Well you posted good news and not so good news.....that listening position plot needs some help....

Based on prior curves you've seen do you think I will be able to equalize a 30 db dip/bump in the response curve with a BFD? I actually had the sub next to my couch previously and it measured much more flat than its current position. Now that was without it being completely sealed but my thinking was that at low volumes it probably didn't make too much of a difference. Its current position is up front between my mains so I'll probably move it back and remeasure from the old position now that it's sealed up. I had originally moved it there because as I was walking around the apartment it sounded really strong there...now I see why...

[Dotay]

I moved my sub back to it's original position right next to my couch and took another measurement.

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Looks a little better but still needs some work. Next step is to get REW up and running and equalize this thing.

Oh, and my fabric came today also. :dancenana:

[---k---]

What does the graph look like with the cross-over set to 80hz and then also with the mains on? You may very well get rid of your big dip like that, or all things could go to hell.

[Dotay]

What does the graph look like with the cross-over set to 80hz and then also with the mains on? You may very well get rid of your big dip like that, or all things could go to hell.

That's a good question...I shall run another test.