I have the bug. It's eating all my free time. $2500 budget for DIY sub

D

Dain Schneck

Freshman
Feb 17, 2014
23
0
0
Dear fellow pro audio guys

I'm wanting, not needing, to design and build my own sub. I love designing and building things but the variables are just astronomical.


I want to do a
A)reflex aka vented aka ported front radiating sub
B)outdoor use
C)for live concert sound

in order of importance
  • $3000 for all components, and materials
  • is not muddy or boomy.
  • is extremely efficient = most spl for the money
  • only need to go down to -0 at 40Hz (this seems to enable higher tuning for more efficient/louder designs)

I don't really care how big it is. I have a truck and trailer. The goal is the most tight high SPL i can manage for that $3000. If that means 12 1x18 boxes great. if that means 2 4x21 boxes, great.

Here is where i'm at in the design so far.
WinISD pro project file via dropbox
I read somewhere that the driver I chose is inefficient. Compared to what? I'd choose something else if it was more bang for the buck.
I'm worried that there will be flabbiness in my latest design because of high Group Delay

The more i read on port design alone, the more worried i get i'm going to design it wrong. There's just too much information out there that's only 80% correct.

Anyone care to point me in the right direction? Shine some light on my madness?
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

First of all you need to define the budget a bit more-as in how do you want to "finish" the subs. Things like grills-handles-wheels-paint type and so forth can eat a lot of the budget up real quick. If you skip all that you can get more subs.

It also depends on the cost of materials where you are at-what shipping costs might be and so forth.

Do you already have all the wood working tools? and skill?

There are 2 basic rules in ported designs. 1: Use PLENTY of bracing-not only on each panel-but also tying sides and front and back together. The stiffer the box the less loss there is due to panel flexing. This also means using GOOD wood-not the cheap stuff you get at the local home depot. There is a reason real boxes are made from 13 ply baltic birch.

The cheap multiply stuff you get from home depot type stores is light weight and no where nearly as strong.

2: Use LARGE ports. Small ports will "choke off" when you turn the volume up-so at higher levels the response will not be as low as it is at lower levels.

This of course means you have to make the box physically larger-since the port volume takes away from the cabinet volume.

I also like to have each speaker in its own chamber. The dividers will make the box stronger and if a driver fails-the other driver will not become as detuned as if they were sharing a common chamber.

Use glue AND mechanical fasteners.

People love to say that the glue they use is stronger than the wood. Well that if fine-until on layer of the wood peels away-then the glue has NOTHING to do with holding it together.

But if you also used mechanical fasteners-screws-glue coated staples etc, then you have that additional strength

I highly prefer rabbet and dado joints. It provides more glue area-keeps things lined up-provides a "stop" for panel movement and makes it MUCH easier to assemble. A bit more work on the cutting side-but the extra value more than makes up for it.

When looking at overall costs-(assuming your time has no value) i would suspect that having fewer better built cabinets with better drivers will provide you with more output SPL and sound quality.

You ALSO have to consider what it would take amplifier wise to drive the cabinets. A lot of cheaper cabinets takes more amp channels and more speaker cabinet and more rack space and so forth-which all add up to the total costs.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain,

Is this your budget per box, or for all "12 1x18 boxes" or "2 4x21 boxes"?

For one box you can probably build a nice subwoofer with real woofers for $3K, as you are discounting all your labor and tool costs. In my not so humble opinion, there is a gulf miles wide between budget 18" woofers and pro level woofers. I don't know what woofer you're looking at, but if you can buy 12 of them and materials to build boxes for $3K I think you are going to be very disappointed.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
I want to do a
A)reflex aka vented aka ported front radiating sub
B)outdoor use
C)for live concert sound

in order of importance
  • $3000 for all components, and materials
  • is not muddy or boomy.
  • is extremely efficient = most spl for the money
  • only need to go down to -0 at 40Hz (this seems to enable higher tuning for more efficient/louder designs)

I read somewhere that the driver I chose is inefficient. Compared to what? I'd choose something else if it was more bang for the buck.

Anyone care to point me in the right direction? Shine some light on my madness?
Click to expand...
Ivan's and Bennett's suggestions are good.

Your "A B C" goals are at odds with your goals "in order of importance", a TH or FLH horn can be 6 dB or more efficient than a BR.
You will increase wood costs (by a little or a lot) but can cut driver and amp cost for the same output by half or more for the same output.

Can't open your design file (try just using a screen capture and post directly) so can't comment on any aspect.

"Group delay" is often misinterpreted, and the phase response of TH, FLH and BR are all frequency response dependent. Once equalized and delayed to match the top cabinets, they can all sound remarkably similar, as long as they are not "boom boxes".

Efficiency of the driver is often difficult to ascertain without looking at actual response in the pass-band region, for example the WS Lab 2x12" design which is a sticky here uses "inefficient" drivers, but still has similar or more output from 35-100 Hz for a given voltage/watts than many drivers rated for higher sensitivity.

Take the same two "inefficient" 12" drivers and put them in the right TH, and they will have the same sensitivity as a larger 2x18" (using drivers that cost 3-4 times more), and because they have more Xmax, can get louder. Put them in a larger FLH, and they can get even louder.

Art
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

It's exciting to see your response so quickly! I'll answer all your questions together.

The $2500 to $3000 budget includes everything for the whole project, including amps (BTW the NU6000DSP looks big bang for the buck), coatings, etc. This will probably only include one driver.

The goal is touring grade construction and finish. So of course recessed handles and a bullet proof coating. What plywood do you recommend Ivan. I know Baltic, but where?

One of the reasons efficiency is such a high priority is because high wattage amps are very expensive.

I'm not sure what TH horn is short for. I like the idea of whatever box design is the most efficient/has the most gain. I had ruled out 6th order because i wasn't seeing useful gains over Reflex in WinISD.


Take a look at my goals again and let me know what you recommend for driver and box design. Art, you're saying a type of horn?
Maybe also helpful would be a break down of the budget, like, 20% wood & materials, 60% driver, 20% amp.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
It's exciting to see your response so quickly! I'll answer all your questions together.

The $2500 to $3000 budget includes everything for the whole project, including amps (BTW the NU6000DSP looks big bang for the buck), coatings, etc. This will probably only include one driver.

The goal is touring grade construction and finish. So of course recessed handles and a bullet proof coating. What plywood do you recommend Ivan. I know Baltic, but where?

One of the reasons efficiency is such a high priority is because high wattage amps are very expensive.

I'm not sure what TH horn is short for. I like the idea of whatever box design is the most efficient/has the most gain. I had ruled out 6th order because i wasn't seeing useful gains over Reflex in WinISD.


Take a look at my goals again and let me know what you recommend for driver and box design. Art, you're saying a type of horn?
Maybe also helpful would be a break down of the budget, like, 20% wood & materials, 60% driver, 20% amp.
Click to expand...

When you say "bang for the buck" you have to be real careful about what type of "bang" you are looking for.

Yes there are different types of "Baltic birch". They all come from the Baltic sea area-there is Russian Birch-Scandanavian-Finnish and so forth.

Any of those will be WAY better than anything you can get at you local "home store".

But be aware of a couple of things. 5x5 is the standard sheet size. You can get 4x8, but it is much more.

Also the wood is not square-so you will need to square it up BEFORE you start cutting or measuring.

If you are looking at a 3K budget and spending 60% of that on a single driver-that is $1800. That is ONE HECK of a driver! or you are paying to much.

The TH stands for Tapped Horn. BE CAREFUL-with any horn loaded TH or regular horn-the choice of driver can make all the difference!!!!!!!!!!!!

Just because it appears to be a "better driver" it may not work as well in that particular design.

Horns and bass reflex cabinets are very different animals when it comes to driver selection.

And Art is correct-you cannot just look at sensitivity specs. First of all without measurements-who know where the number came from?

And when you put the driver in a particular design, you can pick up QUITE A BIT of sensitivity.

Yes that is ONE number-just like watts-but is not the only numbers you need to look at.

Sensitivity numbers (both on raw drivers and finished products) can be VERY misleading-even from top manufacturers.

Yes sensitivity can be your friend. Once you get into larger numbers-a couple of dB get REAL expensive when you look at amp-driver-cabinet costs. It can be less expensive to have a higher sensitivity cabinet-AT THE FREQ RANGE OF INTEREST!!!!!!!!!!!!!!!!!!

Many time sensitivity numbers are stated for freq that are OUTSIDE of the intended freq range. Yes the cabinet can get that loud-but not at the freq you will be using it at. So it is pretty much a worthless spec-except to sell cabinets to people who do not know enough to look closer.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
I'm not sure what TH horn is short for. I like the idea of whatever box design is the most efficient/has the most gain. I had ruled out 6th order because i wasn't seeing useful gains over Reflex in WinISD.

Take a look at my goals again and let me know what you recommend for driver and box design. Art, you're saying a type of horn?
Maybe also helpful would be a break down of the budget, like, 20% wood & materials, 60% driver, 20% amp.
Click to expand...
TH is short for tapped horn, a moniker first used by Tom Danley for a type of horn with the driver located in the mouth and driving the throat, FLH is front loaded horn, BR is bass reflex.
BR can achieve the greatest output per truck space at the most expense.
TH can achieve around double (+6 dB) output per driver compared to BR but take up more space. Unlike FLH, relatively small TH don't require multiples to fill in low frequency response.
When larger cabinets can be considered, FLH and TH can have similar output per size, though TH don't tend to benefit from size increase as much as FLH.

Here is the design that fits my needs best:

Keystone Sub Using 18,15,&12 Inch Speakers - diyAudio

It is close to what you are looking for, but there are other TH and FLH that are larger (or don't go as low), and therefore more efficient in the pass band.
Any designs you look at will always have to conform to Hoffman's Iron law: Loud, low, or small-pick two.
With high powered high excursion drivers and cheap power you can cheat a bit, but not much.

As far as wood, high grade BB is the best, but lighter plywood can achieve near the same results if proper attention to bracing is observed.
The difference in output between the denser, stiffer BB and lighter plywood will be more apparent in the upper bass range than down low.
The difference in cost and weight on a large cabinet can be quite a bit, personally loosing a dB or so up top compared to loosing around 20% weight (for less $$) is one I can live with.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
  • only need to go down to -0 at 40Hz (this seems to enable higher tuning for more efficient/louder designs)
Click to expand...

This may seem logical at first, but you'll find that subs that can go a little lower will typically give you the feeling of "more", even if they don't technically get quite as loud as a sub that drops off higher.

For my DIY $ I wouldn't try to reinvent the wheel. Art's Keystone sub design is well done and uses a pretty stout modern driver, and there are lots of other designs out there that can move some serious air too. The newer generation of LF drivers has really become impressive in the last few years, if you use a high quality driver you will not regret spending that money.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Art Welter said:
As far as wood, high grade BB is the best, but lighter plywood can achieve near the same results if proper attention to bracing is observed.
The difference in output between the denser, stiffer BB and lighter plywood will be more apparent in the upper bass range than down low.
The difference in cost and weight on a large cabinet can be quite a bit, personally loosing a dB or so up top compared to loosing around 20% weight (for less $$) is one I can live with.
Click to expand...


I agree with this and if he plans on using a poor quality amp as the Behringer, he may put the money saved with home depot cabinet grade wood towards a real amp. To the OP, I would think less about '' tour grade fit and finish, and put the money towards components first, not many people look at a rig, they listen to it.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Art Welter said:
TH is short for tapped horn, a moniker first used by Tom Danley for a type of horn with the driver located in the mouth and driving the throat, FLH is front loaded horn, BR is bass reflex.
BR can achieve the greatest output per truck space at the most expense.
TH can achieve around double (+6 dB) output per driver compared to BR but take up more space. Unlike FLH, relatively small TH don't require multiples to fill in low frequency response.
When larger cabinets can be considered, FLH and TH can have similar output per size, though TH don't tend to benefit from size increase as much as FLH.

Here is the design that fits my needs best:

Keystone Sub Using 18,15,&12 Inch Speakers - diyAudio

It is close to what you are looking for, but there are other TH and FLH that are larger (or don't go as low), and therefore more efficient in the pass band.
Any designs you look at will always have to conform to Hoffman's Iron law: Loud, low, or small-pick two.
With high powered high excursion drivers and cheap power you can cheat a bit, but not much.

As far as wood, high grade BB is the best, but lighter plywood can achieve near the same results if proper attention to bracing is observed.
The difference in output between the denser, stiffer BB and lighter plywood will be more apparent in the upper bass range than down low.
The difference in cost and weight on a large cabinet can be quite a bit, personally loosing a dB or so up top compared to loosing around 20% weight (for less $$) is one I can live with.
Click to expand...


This.

I've spent weeks playing around with WinISD and Sketchup trying to design a Dual 18TBW100 cab, designing a cab is in no way straight forward, keeping port compression and speaker excursion in check takes a lot of trial and error.

In the end, the Keystone's measured -3 point is about 4 Hz higher than the calculated -3 point of my box, uses half the drivers/amplifier channels, should achieve a higher SPL level, and most importantly there are already working prototypes out in the wild.

I built four of Art's Dual Lab 12 cabinets last Winter/Spring and they performed as advertised, my B&Cs are likely going to end up in Keystones.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Guys, this thread is really starting to be useful; for sure!

I mentioned tour grade fit and finish....how much do you think I'm going to have to spend to get recessed handles, and one of these coatings: "Tuffcab/Aldcrofts at a minimum, Warnex a bit better, Trimmite better again, 2 part paints (chemthane 7030 & 1400 topcoat) even better, and then if you're really going all out Line-X style polyurea coatings (truck bed liner)"
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

The 4 ohm 21" B&C 21sw152 is what i was designing my BR around. Are you guys suggesting something else for my budget/goals?
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

There is nothing wrong with the 21SW152, Josh Ricci designed a massive Tapped Horn (The Othorn tapped horn - diyAudio) around that driver that reaches down below 30Hz and was capable of pretty high SPL, unfortunately it is large (36x36x24 if I recall) and requires power in excess of 4000 watts to achieve it's full potential.

You stated that you were leaning towards efficiency, and that you were providing audio for live bands, which suggests to me that you don't need response below 30Hz, I'll quote Art from a previous discussion in regards to my BR design:

Let's see-, 10% of your music could use a 1/6th octave extension that no one will notice (except you, if you happen to be comparing it with some GK Ultraphones or a computer), but it costs you double the truck and storage space, driver and amp count.
Most would not find that "worth it".

It took me a while to make the decision that a 35 Hz TH was "good enough" for portable PA use, but in 40 years have never been more happy with any cabinet in terms of output, size and cost per performance.
Click to expand...
The Lab12 PA Subwoofer Smack Down/Death Match - Page 3 - diyAudio

My suggestion, if you really want to build, is either a Keystone sub or a XOC1 TH18 if you prefer the form factor, loaded with either 18SW115, 18TBW100 if you don't mind the weight, or there are also some 18 Sound drivers that are supposed to perform well in these designs.

Otherwise I recommend you check out the real deal, the Danley TH118 if you want to avoid the hours of labour involved in building your own.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
Guys, this thread is really starting to be useful; for sure!

I mentioned tour grade fit and finish....how much do you think I'm going to have to spend to get recessed handles, and one of these coatings: "Tuffcab/Aldcrofts at a minimum, Warnex a bit better, Trimmite better again, 2 part paints (chemthane 7030 & 1400 topcoat) even better, and then if you're really going all out Line-X style polyurea coatings (truck bed liner)"
Click to expand...

That could vary over a couple of hundred percent costs.

It all depends on the overall size of the cabinet-how many handles you need-have you considered how you are going to move it? wheels-dollies etc?

A small cabinet will not take many handles or much "paint". A large cabinet will take much more.

So you can't figure that out-until you figure the design/shape of the cabinet. ANd then there are cheap handles and much better handles that cost more. Maybe you just need 1 or maybe a dozen handles. And don't forget all the hardware (Tnuts-bolts DO NOT use wood screws!) that will have to go with each handle.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
Casters! And good tip on using nuts and bolts on handles and casters.
Click to expand...
My tip regarding casters is don't attach them to the cabinet, they rattle.
For only a few cabinets,(if they are not really deep) two wheelers with pneumatic tires are preferable to casters on uneven surfaces.

You mentioned using the B&C 21SW152-4, using that driver, a Keystone scaled about 16% wider, going from 26.5" to around 31 or 32 inches, would give you about 4-6 dB more output than in a BR with a similar low corner.

The chart below shows a BC 18SW115-4 in the Keystone TH compared to a BR with the same low corner, measured in the same outdoor position with the same drive level.
 

Attachments

  • TH, BR.png
    TH, BR.png
    141.1 KB · Views: 6
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

Dain Schneck said:
The 4 ohm 21" B&C 21sw152 is what i was designing my BR around. Are you guys suggesting something else for my budget/goals?
Click to expand...
I put these together using that driver - basically just "building the box" recommended on the B&C site. I absolutely love them, but my main focus is EDM in rooms of around 250. But I don't think they (or any 21" box) is going to be what you want if you're planning on highpassing at 40hz. Going strongly down another 10hz or so is their main strength. If you're into EDM however there's really nothing else like them at this size. Each one is not much larger than a compact 18" sub. I'm really happy how this project turned out.
 
Re: I have the bug. It's eating all my free time. $2500 budget for DIY sub

This may seem like a swerve but...
This question is for those who do EDM. Would 200ms of latency through your system be an unforgivable issue?
 
Top Bottom