avalanche 15 sonotube, need advices

[wackii]

Hi all,

I've just purchased an ava 15 used. I'm planning to build a sonotube for it. I need some pointers from the experts here. Below is the AVA 15 t/s.

Fs 15.7 Hz
Qms 3.5
Qes .334
Qts .305
Vas 300.6 L
Re 3.2 ohms
Znom* 4 ohms
Xmax 27 mm
Sd 749 cm2
Mms 269 g
Vd 4.04 L
Pnom 800 watts
Le 2.4 mH
Cutout 14.125"
Diameter 15.5"
Depth 7.875"
Weight 37 pounds

I want to make a ported sonotube no bigger than 22" diameter, tuned to 16hz. The height can be tall but I'm worried that it won't fit in my car (toyota camry). Maybe I can get it delivered (depend on pricing)? I ran some numbers on bassbox software. See below:

Images not available

To sum it all up. My box will be 22x56 internal volume (add the driver and the caps, I'm guessing it will need to be like 22x62") with a 8x38" port. These numbers look pretty good. Should I go with this? I need the experts ;x( here to optimize the box design. Can I do better? This is my first time making a sonotube. I need help as to where can I get it? I'm in Los Angeles California. I need a 22" and a 8" sonotube. Thanks.

Al,

Room size = 15x15x9 open to the kitchen = 15x8x9; total = 15x23x9

Currently running mid-q sealed Tempest with 250w.

[SteveCallas]

Couple things - first, I'd feed it with way more than 250 watts, no matter what design you end up with. Second, a 38" long port is probably going to result in a very low first port resonance which may end up being audible. Can you tweak the design to be a bit better? I would have to think so - I can give you my design thoughts tommorrow night, and I'm sure many others will chime in with theirs well before that.

[wackii]

Steve, as of now i have the 250W on my Tempest sub. I'm planning to use that for now. I will wait for you tomorrow cuz' I have no idea about port resonance. One requirement I have is the sonotube can't be more than 22" diameter. Thanks.

Al,

[SteveCallas]

Right now I'm looking at 300 liters with a 6" diameter port that is 27" long giving you ~15.1hz tuning being fed with 600 watts - I'd aim along those lines if it were me. If you want to tune higher to get more output, you'll want to go with a smaller enclosure, but I prefer the lower tune. If you go with too big an enclosure, there will be a large spike in port output which will make room response hard to tame and group delay and port noise will rise dramatically.

[wackii]

Great thank you. I will plug those numbers in. Maybe I can get away with 20" diameter sonotube. Question though, how do you read group delay graph? What numbers are bad? and how do you determint port noise? I'll be back w/ more graphs. Thanks.

Al,

[wackii]

Steve,

I've plugged in bassbox. It gave me the port of 6" dia and 30" long. I can get away with 20" diameter sonotube with 55" height internal volume. Where can I get 6" port? Do they make sonotube with that diameter? Thanks.

Al,

[chasw98]

Steve,

I've plugged in bassbox. It gave me the port of 6" dia and 30" long. I can get away with 20" diameter sonotube with 55" height internal volume. Where can I get 6" port? Do they make sonotube with that diameter? Thanks.

Al,

Go to a plumbing supply store and ask for 6 inch drain tubing. It is usually colored green rather than white like PVC. Ask them if they have remnants so you don't have to buy a whole 10 foot section. That is what I did.

Chuck

PS HD and Lowes don't carry 6 inch pipe.

[nick77]

I found 6" pipe at an irrigation supply store for cheap. A 10' section of PVC is very $$. I found a 7' section of this coax pipe for $11.

[ThomasW]

PS HD and Lowes don't carry 6 inch pipe.

If you find a 'associate' or whatever they're called, most Lowe's have the 6" green sewer pipe that fits the 6" AeroPort flares. But you need to find someone working there that has a brain (difficult) to access it, since it's usually stored out of sight. At least that's how I get it here in Denver.

[SteveCallas]

Question though, how do you read group delay graph?

From what I have gathered, the main concern is avoiding a large spike in too high of a frequency range - you want it to stay as close to linear as possible. With a ported design, you will always have a rise in group delay when the port output comes into play, and its effects won't really be audible in a low tuned design because this rise will occur in a tactile frequency region, but you don't want to make that rise any bigger than it has to be. So the ideal would be to push that rise to as low a region as possible with a low tune, and pick a tuning that suits the driver and enclosure so that the port output blends in with the driver rolloff, not stands out like a sore thumb.

and how do you determint port noise?

If you really want a technical answer, there was a thread on here a while ago about what speed equates to chuffing in various sized ports, but with this design, port noise doesn't look to be a problem.

I've plugged in bassbox. It gave me the port of 6" dia and 30" long. I can get away with 20" diameter sonotube with 55" height internal volume

I don't have bassbox, so just realize that the 300 liters I mentioned is the effective volume after subtracting port and end cap volume.

For the port, either pvc pipe or sonotube will work - just get whichever is cheaper.

[w8liftr]

PS HD and Lowes don't carry 6 inch pipe.

The local Lowes here stocks 6" PVC, but only in 8' lengths, for about $32.00.

[wackii]

Thank you all for the info.

I found 6" pipe at an irragation suppy store for cheap. A 10' section of pvc is very $$. I found a 7' section of this coex pipe for $11.

Nick, where do you find that?

Al,

[wackii]

Pics

I've just received the Ava15. It sits on top of my MidQ sealed Tempest sub. Here are the pics.

Images not available

Question: How do I wire this into 4 ohm or 8 ohm? What do you guys recommend? It has DVC. Currently, I have the 250W plate amp from PE. I'm going to use that for now until I can come up with some ca$h for a more powerful amp. I'll definitely build a sonotube for it in a couple of weeks. For now I just want to switch out the Tempest and am wondering on how to wire this beast (quite heavy).

Thanks.

Al,

[ThomasW]

That driver has 2-2ohm VC's. Your wiring options are 1 ohm or 4 ohms if you want to use both VC's.

http://web.archive.org/web/20050204230512/ascendantaudio.com/Avalanche+15.htm

[wackii]

How do I wire it into 4ohms? Most of the images and info on that link are gone. Thanks.

[ThomasW]

You wire the voice coils in series.

http://www.crutchfieldadvisor.com/learningcenter/car/subwoofers_wiring.html?subs=1&impedance=DVC2x2

[wackii]

Awesome. That's what I need. Thank you, Thomas.

[SteveCallas]

Brings a smile to my face just looking at it

From the reflection, it looks like your binding posts don't accept bananas? That must be an early model I guess.

[wackii]

More pics

Steve, I believe banana plugs will fit in those binding posts.

For those who are interested in comparison between the Tempest and the Avalanche 15, see pics below:

Images not available
Unfortunately, I can't fit the ava15 in my Tempest box. The driver cut-out needs to be bigger I did wire it in series. It does sound much stronger. I did weight the 2 woofers. Ava15 = 37lbs; Tempest = 16lbs. This beast is more than twice as heavy as the Tempest. I can't wait to build the sonotube for it. I will probably need more help on how to build the sonotube in a couple weeks. Thanks all.

Al,

P.S. Ava15 is on the left.

[ThomasW]

I wouldn't use banana plugs in the terminals regardless......

Use a length of tinned wire with the end bend 90 degrees after it's inserted into the terminal. That way it can't vibrate out during heavy use.

[wackii]

pricing on sonotube

I've called 3 places that gave me a quote of $60 for a 22" dia X 60" height. I thought it would be around $40 or so. I just don't want to be ripped off. I'm in Los Angeles California, if you guys know a place that I can get it for cheap please let me know. And if they open weekend will be better. Thanks.

Al,

[nick77]

I am in San Diego and and I paid $28 for 6' of 20" tube from a builders supply store.

[wackii]

Sonotube pics

Today, I went and picked up the sonotube (22" X 60") for $62.45. I couldn't find any place that charge under $60. Also, picked up the 6" x 30" sonotube for $6.25 (for my port). Here are the pics:

The darn thing is huge. It totally cover my 21" cube tempest in the back.

Image not available

Here is the port, taking from the top:

Image not available

I'll need to go get the circle jig, then will get some dust flying. My neighbors will hate me (before and after the sub is done :B ). I'm thinking of cover the tube with carpet. Not sure what I will end up with. Hopefully next week or so, I can complete the cutting.

Al,

[SteveCallas]

Just to act as a last minute check, what height are you planning on cutting the tube to? I'm calculating 52-53". For the port, WinISD is still saying 27" with a flare on the top or 28" with no flare - but an inch or two difference in the port length won't be that big a deal. Good luck :T

[wackii]

I'm planning to cut about 2" off which mean it will be 58" height. Taking away the woofer, the ports (will use 1/2" round over to make it flare out a lil), 4 layers of the caps, it will end up just a lil more than 300L. Right now, I have the tube cut to 30" (will need to make more adjustment if needed). Thanks.

Al,

[SteveCallas]

58"? I haven't done the nitty gritty of finding the exact port and end cap volume for this specific design, but from doing it for a few other designs, I would have to think 61 liters is a bit much, no? For my sonosub which is using 28" end caps and an 8" port, the displaced volume was just under 50 liters. Just trying to help you out some before you take the plunge, always good to double check. By the way, you will be in for a treat when it's done :B

[mboy]

Did you have trouble finding the 22"?

I have heard it is difficult to find as 22" is not a standard or as common as 20 or 24".

[wackii]

Ok, I've just did a lil calculation. Here is what I've got.

1 piece of end cap .75" x 22" = 4.67L <-- I'll need 4 total for my design
I need 4 end caps ==> 18.68 L
1 port of 6" x 24.78" ==> 11.48L or
1 port of 6" x 26.5" ==> 12.28L

1 woofer comes out to be about ==> 12L give or take

About tuning the box,
1. Fb = 15.5hz ==> F3 = 18.4hz ==> net volume = 311L ==> port 6" X 24.78"
2. Fb = 15.1hz ==> F3 = 23.46hz ==> net volume = 311L ==> port 6" X 26.5"

Which tuning looks better (the first one or the second)?

If I take the first option, my box has to be:

311L + 18.68L(end caps) + 11.48L (port) + 12L (woofer) = 353.16L ==> 22" x 56.7"

can someone double check my math? Also, about tuning the box, isn't it Fb should be 3hz lower than F3? Or what is the best option? I won't be cutting anything until maybe next weekend. Please let me know. Thanks.

Al,

[wackii]

Mboy,

Out of 6 places I've called, 2 places do carry 18", 20", 22" and 24". The rest only have 18" and 24".

Al,

[SteveCallas]

Keep in mind that bottom end cap has some pretty decent sized holes in it to accomodate the driver, so you shouldn't calculate the end caps as a whole and the driver as a whole. I just count the end caps as a solid piece and leave the driver out of the equation. Same for the port - if you count the end caps as being whole, then you should only calculate the volume of the port extending below the end cap. If you count them both as fully whole, you are calculating 2x as much volume as you should be.

[wackii]

Ah, thanks for pointing that out Steve. I'll definitely re-calculate everything. I have a tendency to leave or add extra just to be on the safe side. Oh, can you or somebody let me me know regarding the tuning question? Should Fb be 3hz lower than F3? Thanks.

Al,

[SteveCallas]

Umm, if you are ~300 liters and are tuning to ~15hz, the -3db point certainly won't be in the 20's. In the design I mentioned earlier, the -3db point is ~15.6hz.

[wackii]

That's kinda weird. I got those numbers from Bassbox Pro software. If you have time and don't mind, can you help me out with the design? In a meanwhile, I will try unixbox see if I get something difference. Thanks.

Al,

[SteveCallas]

Yeah no problem, check out what I suggested in post #4. That design should perform great - deep extension and solid output, and you shouldn't have to use a highpass filter. If you want to trade extension for more output, you can do that too, as this won't have monster output, but it's definitely respectable. 250 liters, an 18hz tune, and 800 watts would give you more output output, but then you'll need a highpass and won't get super low extension. Basically you have to decide what is more important to you.

It would be great if you were going for two of these so you wouldn't have to make a compromise, but I won't push it

[wackii]

Thanks. I want more deep extension and no highpass filter since this sub is mostly for HT. I guess I will go with 300L with 6" x 27" port. I will probably cut the MDF this coming weekend. The only thing that might hold me back is spending $50 on the Jasper jig for 1 time project. Well, thanks. I'll keep you guys update.

Al,

[wackii]

update

I've got all the end caps cut. I have a few questions:

1. The cutted hole for the port is just a little big (it will go in without using much force), what do you guys put in there to fill in the gap? I have extra wood fill-in. Will that work? I also have tite bond II glue left from other projects. Should I use that instead?

2. What do you guys use to seal the caps together with the sonotube? Wood glue or liquid nail?

3. There's a little waxy layer inside the sonotube, should I take that off before I seal the end caps?

Here's a pic of all the end caps.

Image not available

Thanks for the help.

Al,

Still trying to recover from those MDF dust and glad that I'm getting closer to complete this sub. Thanks all.

[SteveCallas]

1. The cutted hole for the port is just a little big (it will go in without using much force), what do you guys put in there to fill in the gap? I have extra wood fill-in. Will that work? I also have tite bond II glue left from other projects. Should I use that instead?

I would wrap the tube in tape until it was thick enough to create a tight fit. Then use a ring of caulk on both the top and bottom exterior seams where the tube meets the MDF.

2. What do you guys use to seal the caps together with the sonotube? Wood glue or liquid nail?

If you kept tight enough tolerances, you really shouldn't have to use anything - it should already be a VERY tight fit in which you should have to really force the caps into place. I put the bottom cap in first, then went inside the tube and applied a ring of caulk on that interiror seam where the MDF meets the tube.

If you don't have tight enough tolerances (what a slacker, first the port fit is loose and now the cap fit is too :B ), I definitely would NOT use wood glue. Remember that sonotube is cardboard - it would suck up all the moisture in the glue and possibly soften and deform.

3. There's a little waxy layer inside the sonotube, should I take that off before I seal the end caps?

I took it off so that I would have an easier time adhearing the stuffing to the interiror walls.


You gonna round those outer end cap layer edges?

[ThomasW]

The waxy layer is usually a very thin plastic (like plastic food wrap)

I 'grease' the edges of the endcaps with latex caulk. That helps slip them into place, then functions as the glue after it dries.

[wackii]

You gonna round those outer end cap layer edges?

Yes, I will definitely round over the outer caps. I was about to make an 1/2 round-over for the tube, but I messed up and cut it too big :cry: Oh well, I should make a test cut. When it's kinda late, i just rush it through. Live and learn, measure twice and cut once.

I would wrap the tube in tape until it was thick enough to create a tight fit. Then use a ring of caulk on both the top and bottom exterior seams where the tube meets the MDF.

Any tape will do?


If you don't have tight enough tolerances (what a slacker, first the port fit is loose and now the cap fit is too ), I definitely would NOT use wood glue.
I have a tight fit (not very tight though) between the caps and the sonotube.

I'm waiting for the speaker terminals to arrive before glue the caps together.

Thanks for your help.

Al,

[ThomasW]

Use a paper based take like masking tape, I wouldn't use duct tape or electrical tape.

If the gap is big, cardboard drywall shims are a good option.

[wackii]

The waxy layer is usually a very thin plastic (like plastic food wrap)

I 'grease' the edges of the endcaps with latex caulk. That helps slip them into place, then functions as the glue after it dries.

I still need to pill that waxy layer off right? Just want to be sure.

Thanks.

Al,

[ThomasW]

I'm lazy so I leave it on. Others choose to peel it off.

I have no info that one way is better than the other.

[wackii]

More parts questions

I'm going to order a few items from Parts Express. I need you guys help again.

1. 8" speaker grill to cover the 6" port
2. 2 speaker terminals
3. I want some speaker screws to mount the woofer. I don't want T-Nuts since I'd worked with it before and had a hard time align it. Anyway, I just want some speaker screws from parts express. What do you guys suggest?

Thanks.

Al,

[SteveCallas]

1. I'd go with the 10" cover - you don't want the rim of it being too close to the actual port opening or flare.
2. Unless every penny counts, I think these would serve you better due to your thick baffle.
3. There is a recent thread on here where JonW was looking for some flat head coarse threaded screws, and several sources came up, try looking for that. I'd feel safer with bolts and t nuts though :roll:

[wackii]

1. I'd go with the 10" cover - you don't want the rim of it being too close to the actual port opening or flare.

Thanks.

2. Unless every penny counts, I think these would serve you better due to your thick baffle.

Thanks. I was hesitating on these because I don't know what size of the hole should I drill and also it might be a little shorter than my thick baffle (3 layers = 2.25").

3. There is a recent thread on here where JonW was looking for some flat head coarse threaded screws, and several sources came up, try looking for that. I'd feel safer with bolts and t nuts though

I will check out his thread. The reason I don't like bolts or t-nuts is that I have a hard time aligning them, plus Ill probably not going to take the woofer out much.

Thanks.

Al,