Large.. Dual 15" RL-p Unit

[steve nn]

What I'm looking at doing is building a dual driver 15" SS RL-p tuned to 16.2 Hz. This is going to come in pretty large at 20.8 cu ft with needing to net 18.3 cu ft after factoring. I'll be pushing each driver with 750 watts with the EP2500. I'm definitely going to have to pick up a few more clamps for this guy and needless to say.. it wont be a sub I go in the garage one day and come out the next with the sub on the cart ready to load the driver.

I'm not sure if I really have any questions, but for those that have built such a large unit, I'm sure it's going to be a learning experience and any advice would be appreciated. The sub will measure 29W X 49H X 29D at .75 thick. I still need to come up with a fancy bracing design come to think of it. It'll have flared ports coming out the top with the top being flush with the ports.

I would like to stay at .75 thickness if possible with the baffle coming in at 1.5 and the top coming in at 1.5 for the flared ports. With my last sub coming in at 20 X 39 X 20 it worked out very well, but admittedly I'm sure it will be suggested I go 1.25 or so? Thomas might suggest 3". If it were the sealed design, I wouldn't consider going less than 1.25. If I go much thicker with extensive bracing..its going to take a crane to get this thing in the house though..you guys need to take note I'm 47.

I would like to Thank Steve C for his help thus far on this project in simming it out and certain suggestions pertaining to tune. I would also like to Thank Thomas for setting the hook in my last Thread. You two might be my biggest enemies afterwards, but I hope to have fun doing it and of course learning more about this wonderful hobby.

Last two projects although one never made it to the finish stage>>

[FlashJim]

That's going to be one heavy beast. I'm looking forward to hearing more about the project. Keep us posted!

[steve nn]

That's going to be one heavy beast. I'm looking forward to hearing more about the project. Keep us posted!

Will do Jim. I'm going to give this my best effort. Being that it's so large and not wanting veneer lines..I'm thinking of a few ways to incorporate a few other options in the finish process.

[---k---]

Questions:

1) Why not two smaller, collocated ported subs? Easier to move around.
2) Why not Tubes? Obviously you've had tubes in the past.
3) Are you ever going to give it a rest and enjoy them?

[Mark Seaton]

The sub will measure 29W X 49H X 29D at .75 thick. I still need to come up with a fancy bracing design come to think of it.

STOP!!! Go measure your doorways and make sure you can get it into your room! :E

Note this comes from someone who has had to bust out the Sawz-All to get a subwoofer to make it around a corner. :roll:

Having played with a few subs that "looked smaller on paper" I would suggest shrinking one of those 29" dimensions unless you have mocked it up in cardboard. That's a bulky box.

If you are still in the clear, I would suggest you look at using more bracing than thickness for a sub of this size. If you read through some of Sigfried Linkwitz's site you will see some good references for resonant frequency of a panel to help with justification of how much bracing is needed. Depending on how you plan to orient the beast, do consider opposed mounting of the drivers. This way you can focus on the bracing and keep weight as reasonable as possible.

Of course that's just my oppinion.

[SteveCallas]

1) Why not two smaller, collocated ported subs? Easier to move around.

You know, that's a good question. One reason to stick with the larger dual design is that he has to the potential to get away with using a single 10" diameter port and reducing port velocity dramatically. As for the tubes, I already tried....unsuccesfully :B

[ThomasW]

Should be nice and loud ...:wink:

If you want to use 3/4" material, pay up and get some 13 ply Baltic birch.

Just use window bracing, you can cut it to support the port if you plan carefully.

I would also like to Thank Thomas for setting the hook in my last Thread. You two might be my biggest enemies afterwards, but I hope to have fun doing it and of course learning more about this wonderful hobby

? This isn't a competition. There's plenty of work for everyone leading the world to the path of DIY Bass-enlightenment...:wink:

[steve nn]

1) Why not two smaller, collocated ported subs? Easier to move around.2) Why not Tubes? Obviously you've had tubes in the past.
3) Are you ever going to give it a rest and enjoy them?

1> Been there and done that. I cant get two 16hz tuned box subs in the same corner without going overly tall. Good idea though.
2> Refer to 1.
3> When I stop enjoying it as much as I presently do. DIY has also afforded me much more latitude in finances and the WAF...it is what it is.

STOP!!! Go measure your doorways and make sure you can get it into your room!

I hear yuh Mark! That was the first thing I did though. Our doors are 36" with 34" of clearance...I always load the drivers in the house so that will be a help. Oh!..actually the sub will be 50" H due to not adding a calculation into the original final height.

? This isn't a competition. There's plenty of work for everyone leading the world to the path of DIY Bass-enlightenment...

Oh heck I know that Thomas..this is to utilize both drivers more than anything. I was just playing around giving you a little guff is all.

If you want to use 3/4" material, pay up and get some 13 ply Baltic birch.

That would be nice, but I'll use lots of bracing along with some good help in getting it in the house. If I could go deeper or wider it might change things a little, but as it stands.. I will only get one panel out of each sheet. I just started to do the preliminary on that though.

[steve nn]

Depending on how you plan to orient the beast, do consider opposed mounting of the drivers. This way you can focus on the bracing and keep weight as reasonable as possible.

Sorry I missed this Mark. No I really don't have that option considering it's placement. Both drivers need to be forward firing or bottom-forward firing. Bottom firing one of the drivers would present a whole different set of problems, but then it would negate the apposing mounting benefits anyway.

You know if one really thinks about it, this sub wont be that much larger than the two 22" sealed units I had previously stacked with the added eq config sitting on top. I just found a 49" X 29" piece of MDF out in the garage and brought it through the doorway and checked it out. I think things are going to work out just fine although it will have it's challenges. The thing I could really use is another set of arms and hands on this one.

[ssabripo]

Steve...what pipe are you smoking man?!!!

man, and I thought I had an addiction with DIY....holy schmoly!!! what are you doing with the older cabinets?

[SteveCallas]

This sure will be a pretty big box....given any more thought to the 10" port? The RLp15s look to be about 9" deep, so with a 29" by 29" cross section, there should be plenty of room for it. And one piece of 10" sonotube will weigh less than two pieces of 6" pvc.

[steve nn]

Steve...what pipe are you smoking man?!!!

I lost my pipe back in 75.. I'm thinking about taking it back up though. :lol:

what are you doing with the older cabinets?

I'll keep one of the sealed for sure, but I'm not sure about the last one I built? This will be my last big sub as far as I know. I'll play around building comparatively small subs from here out..I'll need to snag a 12" driver and build a extra shelf in the garage.

one piece of 10" sonotube will weigh less than two pieces of 6" pvc.

Being I'm going to cover it and the option of only having to do one, it might be a good idea! I'll make a few calls today if I have time and see what I can find. With the last unit having a 6" port (no flare) and not having any problem with chuffing, it would strengthen the idea of not having to worry about the flare. I know a hardware store close by has some sono, because I saw it when I picked the 6" PVC.

[steve nn]

And one piece of 10" sonotube will weigh less than two pieces of 6" pvc.

On the other hand it's going to take up another .5 cu ft over the two 6"s. I think with shaving off the double layer of MDF for the top, (no flare) it'll still bring me in pretty close to what I originally specked out.

[steve nn]

I just gave the little hardware store a call and all be darned if they have it in the 10" ID.:E It's funny how all the big guys (HD-Lowes even Pluming supply stores) haven't been able to help me out in this area, but they consistently have. Maybe I ought to give them my MDF business while I'm at it.

[SteveCallas]

Yeah, you won't need the double layer on top anymore. What I would do though is save a couple of the driver cutout circles and cut a 10.25" diameter (or whatever the actual OD of the sonotube is) hole in them to use as a support ring for the port, similar to the second picture in this post by Jon:

https://www.htguide.com/forum/showpost.php?p=246445&postcount=16

One more support for it near the bottom as part of a brace and it should good to go. I dare say, you will have the largest port ever (as far as I know) if you proceed with this :B

[steve nn]

I dare say, you will have the largest port ever (as far as I know) if you proceed with this :B

Cool! This will be a port where no port has gone before. Lookes like a DIY dust pan should be my next project.



Well I made a little progress today. My wife came out and said your not going to put that in the house are you? I said> It's no bigger than the two 22" cubes that I had stacked there prior..kind of a little white lie, but she fell for it. I better hide those cubs pronto!

[Exocer]

steve, will you be allowing company over to listen once its done? i'll bring the popcorn :T

btw, lots of progress. congrats

[ThomasW]

What kind of clearance do you have for the port in relation to the walls of the cabinet?

[steve nn]

steve, will you be allowing company over to listen once its done? i'll bring the popcorn :T btw, lots of progress. congrats

Thanks Exocer.. popcorn would be nice, along with your company. 8)

What kind of clearance do you have for the port in relation to the walls of the cabinet?

I know this guy who wouldn't allow less than 10" (I think) to be up to his standards, so 10" it is. This has been the most wasteful project I have done thus far considering I can only get one panel per each 4 X 8 sheet. Some will be used for bracing of course, but if I could have went a few inches deeper and wider, with reducing the height, it would have pen$iled out much better. Leftovers are always nice though.

[SteveCallas]

This is going to be one badass subwoofer ;x( Congratulations, the temptation I know will be created after I see your finished product will probably force me to assemble sub #2.

[steve nn]

This is going to be one badass subwoofer Congratulations, the temptation I know will be created after I see your finished product will probably force me to assemble sub #2.

Lol..It's goanna be a doozy alright.. this thing should really rock! Panels that size are a little tricky to work with that's for sure. Hey Steve..don't you notice something a little odd in one of the pics?

[SteveCallas]

Hey Steve..don't you notice something a little odd in one of the pics?

You aren't building two of these dual driver beasts are you? 8O

[steve nn]

You aren't building two of these dual driver beasts are you? 8O

Only if I need to.:P No the little hardware store let me down. It was 10.5 ID so I went ahead and picked it up anyway. Afterwards I found what I was looking for at HD..so it'll be going back.

[steve nn]

What kind of clearance do you have for the port in relation to the walls of the cabinet?

Well it looks like I lied to you Thomas. The driver is 1.5" deeper than what I thought, so it looks like about 7" from the back with 1' clearance up front from the back of the magnets.. with 8.9" on the sides.

[WillyD]

Holy mother of god.

That sub will be ridiculously badass.

[steve nn]

That sub will be ridiculously badass.

I'm out there trying to figure out some bracing around that bad ass Steve C 10" port. :cry: :T

[SteveCallas]

What about just a horizontal shelf centered between the drivers?

[steve nn]

What about just a horizontal shelf centered between the drivers?

I'll post a pic latter and we'll see what you think. Once I started thinking of attacking it like on the last project, it came together. Now lets see if the port makes its way through both holes with out getting skewed. Thanks Steve..

[Ilkka]

What the hell?! :E I guess the first vented sub wasn't enough then. 10" port...oh my.

Be sure to use a lot of braces.

edit: I just simulated it...you're looking at 113 dB or more at 16 Hz and above @ 2 m.

[steve nn]

I guess the first vented sub wasn't enough then. 10" port...oh my.

Oh it was plenty and sounds great! I just figured I would go for it since I already have the two drivers.

I made some headway today, but I don't have it in me to finish it up minus the finish work. The back panel is cut, but I still need to router out the terminals. Then it's the trim bit and in the house she goes. After this project the router is going to take a rest.









My turbo

[Hdale85]

......Wow just wow.

[chasw98]

OK, thats cool Was there even enough time for the glue to dry? Talk about quick execution!

[Hdale85]

Yea i know ive been following this thread and didnt even see this beast until today.

[SteveCallas]

With the box being that big, using .75" thick walls, do you think that is enough bracing? I've never built a box so I have no idea, but I would have thought bracing in both directions would be desirable.

[Hdale85]

It's only 3/4 inch thick? That doesnt seem like its enough.

[ThomasW]

I do like your Turbo option.... :T

It will certainly impress when the glass blows out and flocks the listeners ...:wink:

Some vertical bracing would help to lock the structure together.

My suggestion is as follows. Fire up and test the sub with the box unfinished. If you can feel significant vibrations on the sides of the enclosure, think about laminating a second layer of material around the entire box.

[steve nn]

If you can feel significant vibrations on the sides of the enclosure, think about laminating a second layer of material around the entire box.

I think that might be the way to go if it requires it. I need to step back from it for a day or two and think about it..after that I should be ready to go at it in a more productive manner. In the last 36 hrs I must have spent at least 26 hrs or so on it, in some way form or another. That 10" port creates a challenge, but nothing that cant be worked around if the desire is there. It's actually fairly solid and doesn't do to bad with the rap test..also when the back goes on, it'll be better yet! All and all I better spend some more time on bracing though.

but I would have thought bracing in both directions would be desirable.

The bottom is braced Steve. The top will get two braces like the bottom brace on the front and back of the port across the top..maybe I'll come up with something else also? Vertical wont matter as long as this is done..it will serve the same purpose. Remember I'm going to have two drivers on the other side (which is doubled 3/4) and the 10" port to contend with. It's a good Idea though (more bracing) and thanks for egging me on.

EDIT>

I do like your Turbo option....

I was hoping you would. There's allot of technology wrapped up in that device.

[steve nn]

......Wow just wow.

Thanks

OK, thats cool Was there even enough time for the glue to dry? Talk about quick execution!

When a guy devotes a couple days including a evening, he can get allot done...plus Bass is a great motivator.

[---k---]

Steve,
Can you stick that thing on a scale when you get the front panel attached. I'm curious about your weight. No reason in particular...




I'm in trying to be such a good boy and not dream about building another sub, but you people are making that very difficult!

[Hdale85]

Yea seeing a dual 15" sub with a 10" port makes me want to build one.... How tall is it? i dont think it would fit anywhere until i move into my house in like a year i'll probably have to stick with the single or dual TC2+ 12's im planning on building.

[steve nn]

Steve, Can you stick that thing on a scale when you get the front panel attached. I'm curious about your weight. No reason in particular...

Hey Ryan..I'm not sure if I can or not? The only scale we have around here is a bathroom scale. Being a 29" footprint.. I wouldn't be able to read the scale and lifting it and standing on the scale is certainly out of the question. I should be able to come up with a fairly close guestimate though. I'll be sure to weigh the back panel before it gets screwed and glued.

I'm in trying to be such a good boy and not dream about building another sub, but you people are making that very difficult!

If this sub sounds as good as my last project, this is going to be it for me for awhile..Cross my heart. It'll be your turn to whip something up for the family. 8)

Yea seeing a dual 15" sub with a 10" port makes me want to build one.... How tall is it?

It's 29"W X 50H X 29D with hoping to come in at around 18.3 cu ft.

i dont think it would fit anywhere until i move into my house in like a year i'll probably have to stick with the single or dual TC2+ 12's im planning on building.

Two 12"s or one 15" have the propensity to put out a good amount of bass with the dual 12"s being a little more. Some day I wouldn't mind checking out the TC2+. From what I hear your in for quite a treat.

Anyway a little sleep seamed to clear up my motivation, but we have other things to do today..darn! I guess life goes on even though we get wrapped up in a project. :P

[derekbannatyne]

Just curious, how come you could only get one side panel out of one 4x8' sheet of MDF? I thought that they were actually 49" wide.

[dyazdani]

I had the same issue while trying to weigh mine. I can lift it, but I don't really enjoy it.

If you have two bathroom scales, you can set part of the box on each, you then just add the two weights together.

[steve nn]

The wife could be angry at me for staying home but this is really shaping up. I put a vertical in, plus another bottom and top brace. I think it's time for the back panel which is already cut.

[SteveCallas]

Excellent, now you're in business! This is a very exciting thread to follow