Help! Another Sonosub

[-Haro-]

I've spent some time reading the great posts here and they have answered countless questions, but I still have a few of my own.

I want to build a Sonosub for my 20x24x7 basement that is used mostly for HT. I have my sights set on a new 15 or 18" Ascendant driver whenever they arrive. This being said, can I start the enclosure construction before I know the T/S parameters of the driver? I am thinking of 28" sonotube anywhere up to 5.5' tall with a 6 or 8" port?

Unfortunately I can't do IB

If I can start this thing in the next week or two it would be great. Thanks.

[KeithM]

You can put one of the endcaps on the sonotube, but without knowing the cubic feet you need, then put spikes on it and put the binding posts in it. That's about all you can do.

[ThomasW]

Actually you can probably build the whole thing, since fundamentally a ported sub is just tuned to itself.

You should probably go look at a piece of 28" tube, because they're HUGE in person.

Go for a 6" flared port those move as much air as a 7" straight port but can be shorter.

You can buy the ports here if you live in the US.

http://cgi.ebay.com/6-AEROPORT-AERO-PORT-AEROPORTS_W0QQitemZ5830473218QQcategoryZ14932QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

You'll end up throwing away the center section since it will be too short for a low tuning.

[-Haro-]

With the flared ports you just cut the ends off and attach them to 6" diameter tube of whatever length you need?

When you say tuning to itself, you mean I would build say a 600L sub now, then vary the length of the port until I got a good curve for the desired driver when it becomes available?

This is my first DIY so I'm still trying to get the methodology down here... Thanks

[Paul H]

With flared ports you just use two flared ends and cut the middle section (before it's joined to the flared ends) to be the length you need.

The tuning comment referred to the fact that the port is tuned to the box size (volume), not the driver. The tuning frequency would not be changed by using different drivers in the same box.

Paul

[---k---]

600L? Are you looking to build a Steve Callas clone?

[-Haro-]

Besides height, I would like to build something quite similar to Steve's sub. He did an admirable job designing and building it and I'm sure the output is simply amazing. I don't think I will be doing 3 layers of MDF per endcap though, 2 + Plywood at most.

I modeled a 28" diameter x 5'6" tall sonotube and came out with 665L without driver and port. When I model this volume in WinISD Pro with a 15" Tempest or RL-P15 I either get a nasty hump at 20hz or with the RL it drops off completely before 100hz? I am varying the port length from 8" to 30" and can't get a smooth curve with this volume.

Am I plotting this correctly??? I don't want to build a large enclosure and find out no driver will sound good in this beast!

[ThomasW]

What's the fasination with Steve's design? The primary thing a monster enclosure provides is a bit higher overall efficiency. And of course bragging rights about the size of one's ........

There aren't any suitable 18" drivers available right now.

Here's a link to a tube sub we helped Marcus Jones create using the RL-p 15"

http://www.htguide.com/forum/showthread.php4?t=15870

Drivers that have a high Le (like the RL-p 15) roll-off in the top end in a computer sim. But it's usually not a problem.

Do not get fixate on having a ruler flat FR in a computer sim. Here we deal with the real world performance. And in the real world the influence of the room makes the flattest computer sim look like the Rocky Mountains...

[SteveCallas]

Lol, I'm not suffering from any Freud issues (at least I don't think I am ) and I don't drive a big pickup truck. I really liked the way Joe's looked and from what I had read, going bigger with a ported design, up to a point, eliminates a lot of the drawbacks of going ported.

Wouldn't he want to see how each tune interacts with the overall design? Not necessarily FR, but also group delay, port velocity, and cone excursion?

[ThomasW]

Steve,

Would you post the specifics of your design? I've only seen the pics, and I'm not really in a mood to plow through a ton of posts/threads for the details.

Thanks
Thomas

[SteveCallas]

651 effective liters, 8" diameter port that is 53cm long, 3/4" round on outer MDF layer used as a flare, 600 watts in 4ohms.

Mark Seaton had suggested a 12hz tune after the fact, and that betters a few things, but I'll wait until I am in a more permanent housing situation (basically when I buy a house) and see how that would affect my low end in room.

[ThomasW]

Thanks.....

[SteveCallas]

Give it your worst :B - I'm interested in any opinions you have on things you would have changed or tweaked.

[-Haro-]

I have a complete newbie question if this makes sense.

What T/S parameter measures driver volume? I am tring to figure out how much space the driver will occupy within the tube and can't figure it out for the life of me.

At this point I guess all I can do is buy the materials and maybe cut the top endcap and port hole. Whenever the drivers show up I'll cut the tube and make the other endcap? Oh well.

And Thomas, I'm with Steve on the "largeness" issue. No big trucks, belt buckles or tight jeans here.

Seriously, like most here I'm just looking for the best design for deep, great sounding bass in the space I have available. I currently run a Rocket ELT SW-10se sub and though beautiful and musical, it doesn't cut it for movies. I need more Bass!!!

As always, thanks for your help.

[ThomasW]

Ben,

The amount of air displaced by the driver itself isn't one of the T/S parameters. If the information isn't provided separately by the mfgr, one just makes an educated guess. The average 15" driver usually displaces ~5L, and 18" will be 6.5L or more

Understand that there's really a 10% 'fudge' factor with ported boxes, so don't sweat the small stuff.

BTW if you want to save the $50 on the flares go with a 8" port like Steve did. But understand doing that will mandate a taller enclosure since the port length gets longer as the port diameter increases.

[-Haro-]

Thanks Thomas, that's what I needed to know.

[-Haro-]

Last question for the day.

Anyone here know where to get 6" flared ports?

I found this site, anyone use them before?

http://www.2loud4you.ca/shop/index.php?main_page=product_info&cPath=1&products_id=3

Ben

[ThomasW]

I put a link in the 3rd post of your thread.

[J-Dub]

If you can't get you hands on Aeroports like Thomas suggested, or 50 bucks is out of range. I used 6" PVC attached through 2 layers of 3/4" MDF the PVC attached to the back of the third layer of MDF and I used a 3/4" roundover bit in the router to make my own flare. If you like you can do the same thing on the inside by laminating two 9" diameter pieces of MDF together. 1st rout a hole in one piece that will just barely fit over the PVC. 2nd laminate the two pieces together. 3rd place on top of pvc like a cap and glue with a lot of liquid nails. 4th rout out the top with a roundover bit that has a bearing guide at the bottom. ps. before you use the roundover bit you will need to start a hole with a plunge cutter. then use a straight bit with a guide bearing to "find" the inside of the pvc. after that the roundover bit will do its magic.

Man this is where a picture IS worth a thousand words

sounds like a lot of work but hey, it is DIY :B and honestly it goes by a lot faster than it sounds.

[ThomasW]

Bob C. (aka collo)has a very detailed DIY section for making flares on his website

http://www.users.bigpond.com/bcolliso/port-flares.htm

[-Haro-]

Hey thanks for the additional ideas and links. I am going to try and purchase a 6" port from one of the suppliers listed in Thomas' link.

If I'm able to find some available I'll post back with the results in case anyone else wants to buy some.

Ben

[wildfire99]

I used 6" PVC attached through 2 layers of 3/4" MDF the PVC attached to the back of the third layer of MDF and I used a 3/4" roundover bit in the router to make my own flare.

I did this recently on some 2" ports. Is 3/4" really enough radius for a 6" port? (But yes, it is rather easy and looks great too.)

[-Haro-]

Bit of an update...

I spoke to Chad from Ascendant Audio yesterday and am thinking of now going with two 15's in opposite ends of the sonotube. I wanted to go ahead and purchase the 12's he has available now, but think I want a little more overkill than that.

So in the month or so until the 15's become available, I'm trying to get ideas on the dual driver idea. Any readily available projects on the internet where someone has done this?

I know there is a thread going here right now where steve nn is doing this in a box with the RLP's. Is it basically the same idea? Any resonance issues in the tube with dual drivers?

I picked up two 6" ports from the Canadian dealer today and am going to pick up the Sonotube and MDF tomorrow.

Ben

[J-Dub]

I did this recently on some 2" ports. Is 3/4" really enough radius for a 6" port? (But yes, it is rather easy and looks great too.)

To be honest, there is not even a modicum of wind noise. On my next project I will probably use either a larger bit (1.5" if I can Find it) or do something like the bondo in Thomas' post. Better safe than sorry and I think the larger Radius will look a whole lot better! The sub I built also had two 6" ports so the effective port opening is twice as large.

Good question for Thomas: People seem to think if you have a larger port you will need a larger flare radius but if you have a larger port essentially you are releiving the air constriction from the outer edges of the port perspectively. Indeed if the port is flaired this will allow the air to ease its way into the tube rather than crash in over the edge like a rock in a river. but if you have eleviated most of the air's constriction by reducing the intensity of the bottleneck would you still NEED a larger radius on the flare?

It would seem to me that if you were using a port that was just a bit too small in diameter for the enclosure that you could better its performance a hair by increasing the radius of the flare. (Edit: Rhyme unintended )

[ThomasW]

There are never any cabinet resonances issues with a tube sub.

Although a sealed design, my Tube-Zilla is a dual 15" driver tube sub.

When you have upper and lower woofers be sure to make a wider than normal base plate, since the center of gravity shifts. Also you want a bottom plate on the top so the loading on the drivers is equal. Doing that helps protect the driver. I made the upper plate 2" dia smaller and think that helps balance the looks of the design.

[-Haro-]

After further research and thought I have found I can only get 24" or 30" Sonotube in my area. To get it in my door I will have to go with the 24".

I don't think it's possible to fit a 15" driver and a 6" flared port with a 9" mounting flange on a 24" end cap. Therefore it looks like it's one driver per sub.

Thanks for the link to your Tubezilla Thomas, I was reading it the other day for router ideas and forgot it had dual drivers.

[chasw98]

Thomas:
Have you ever measured the performance of Tube Zilla? Can you divulge what the dimensions of the sonotube are (diameter & height) and what drivers you put in it. How does it sound?

[ThomasW]

Chas,

All the dimensions are on the website.

I haven't measured it. I built it sort of as a joke since I built tube subs for a dozen or more other people, and never built one for myself.

We played around with it for a week and ever sense it's been gathering dust in the basement

It's a very small enclosure for 2 BP1503's. Were I to actually use it (perhaps in a vacation home) an LT circuit would be mandatory as would a BIG amp..

[chasw98]

Dumb me. I just looked at the pretty pictures (and the nice router!). What does "LT" stand for?

[ThomasW]

Linkwitz Transform circuit

[-Haro-]

I was checking the old sonosub builds and came across this example which used acoustic foam to line the insides.

http://home.comcast.net/~audio-worx/page93PetesTube.html

I am about to purchase something to line the inside of my sono, but am not sure if it's worth spending the $80 or so to use the foam or just use batting from a craft store.

Are there any noticeable acoustical advantages of using the foam in a ported tube?

Along with this, do most of you stuff your ported tubes with batting along with the lining?

Ben

[J-Dub]

I am about to purchase something to line the inside of my sono, but am not sure if it's worth spending the $80 or so to use the foam or just use batting from a craft store.

Are there any noticeable acoustical advantages of using the foam in a ported tube?

Along with this, do most of you stuff your ported tubes with batting along with the lining?

Ben

I used $13 eggcrate for a full sised bed from wal-mart. disadvantage: it only came in pink ohh well, nobody is ever going to see the inside anyway.
I'm sure Thomas knows if there are any acoustical no no's in using this. I think it worked well in mine.
I diddn't stuff the enclosure just batted the whole tube including all areas around the driver, back wall, port, etc...

ohh BTW inside the sonotube there is a thin plastic waxy film. if you want anything to stick to the tube you will have to remove it. start by finding a little "tip" at the edge of the sonotube, lift it up and start pulling. make sure you pull only the plastic not cardboard. it will come off in one big strip.

[ThomasW]

Along with this, do most of you stuff your ported tubes with batting along with the lining?

Nope just line the walls of a ported sub. If you want to save money, go buy some 3 1/2" thick fiberglass insulation from a home center store. Regardless of cost, it's the best damping material available for low frequencies .

[-Haro-]

I used $13 eggcrate for a full sised bed from wal-mart. disadvantage: it only came in pink ohh well, nobody is ever going to see the inside anyway.

Great idea actually... I had my mind set on the egg crate foam at Parts Express that would cost an arm and a leg with shipping.

ohh BTW inside the sonotube there is a thin plastic waxy film. if you want anything to stick to the tube you will have to remove it.

Didn't even think of this, thanks for the heads up.

If you want to save money, go buy some 3 1/2" thick fiberglass insulation from a home center store.

I have some sitting around from another project. I might as well use it up for this project. Thanks Thomas.

I'm going to cut and glue the mdf together tonight. Then comes the routing. Makes it kind of tough when I don't know the dimensions of the driver. Wish me luck.

[ThomasW]

I've never needed to remove the film from inside the tube. I just use hot glue or liquid nails to adhere the damping, seems to work fine...

[SteveCallas]

Haro, so what have you decided to go with? Ported/sealed, driver(s), volume, amp, etc.

[-Haro-]

We're back in business.

In the past two weeks I've cut the sonotube to length 24" x 66", cut the endcaps (dual 3/4" MDF inside with 3/4" Birch Ply outercaps), recieved the 6" aeroports and cut the port holes in the top caps.

I also purchased a Behringer ep2500 and a BFD 1124p. I'm driving my mains with the Behringer right now and WOW! It sounds nice. :B

I've been waiting for Ascendant to release their new home drivers, which they haven't quite as of yet, but they released some specs for the Alliance 18.

Here's the specs: http://www.ascendantaudio.com/allliance_page.html

Znom 4 ohms BL 17.24 n/a
Re 3.8 ohms Sd 1185 cm2
Fs 14.6 Hz Mms 362 g Mounting depth 8 5/8
Vas 657 L Xmax 20.5 mm Weight 25 pounds
Qms 10.79 Spl 88.7 dB 1W/1M Voice Coil diam. 2.5 inch aluminum
Qes .425 Rms 750W Voice coil Single 4 ohm
Qts .409 Cone: Paper/Kevlar fibers
Le 2 mH

When I model this in WinISD pro with a 440L tube, and one 6" port tuned to 14hz it hits -3db at 17 or so hz. If I had Steve's monster I'd be at -3 at about 13-14hz. Therefore, is this too much driver for my not so little tube?

I would like to put an 18 in my sonosub, but looking for the best response. Any help modeling this would be much appreciated as always.

And sorry Steve, didn't see your post until today.

Thanks

[ThomasW]

To fit the flares you're going to need to buy 6" green sewer pipe. Standard 6" white PVC won't fit the flares. Once you get the pipe measure the ID and use that for you box model. I don't have any scrape pieces around, I think the ID is around 5 7/8", so it's smaller than the 6" box model.

[chasw98]

I just acquired 3 feet of 6 inch green sewer pipe and it is indeed 5 7/8" Inside Diameter.

[-Haro-]

Gotcha. Thanks for the heads up.

I have the 11 inches or so of tube that came with the aeroports, but based on the 14hz tune the modeling I have now it gives me about 16" for port length. Does this seem too short or is it just me?

What application does everyone use to post pictures? A link to a how to or just a "copy and paste, stupid" would work. Thanks.

[ThomasW]

You can upload up to 3 attachments per post by using the "Manage Attachments" button in the "Additional Options" section.

[-Haro-]

I was all set on using the new Alliance drivers in my ported sonosub, but the low XMAX is killing me when I model it. I reach full excursion at 300W, which I suppose isn't a bad thing, but I want some room to spare ya know?

Therefore, screw keeping this thing a budget sub, I'm going with a new Tumult.

http://www.acoustic-visions.com/~acoustic/products/subwoofer_drivers/adire_tumult_15/

What I need to know is whether I should go with the 15D4 or the 18D4? I don't mind spending the extra $$$, but the 15 turns my tube into an EBS... a little less max SPL, but it's down 3db at 13.5hz! 8O

Any thoughts?

[-Haro-]

An idea of what I'm dealing with.

[SteveCallas]

You reach full excursion at 300 watts but what spl does that equate to? It looks like AA specifically made that driver to not require a lot of power. The only thing that worries me is why does it weigh so little?

[ThomasW]

Unfortunately Tumults have been "coming soon" for months, and months, and months..... Adire is apparently having issues getting product from CAC.

So you might want to consider something that's actually available as opposed to vaporware....