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Crash course on designing a sealed cab?

L

LuvHz

Apr 16, 2025
5
1
#1
Long time baritone guitar player (Drop F tuning) looking to make a sealed cab for an EVM-15L.

Is there a simple calculator or piece of software I can use where I plug in speaker parameters and it outputs cab dimensions/internal volume?

I’m completely new to cab design/building and this is my first build.

I want a sealed cab just because I play baritone guitar, not bass, so I don’t need super extended low end just want more beef/punch overall. (Am I right in thinking this way?)

I also want to be able to mic the cab without having to worry about also micing a port/vent as well.

A perceived side-benefit I see with a sealed cab also is that I might be able to try other speakers in it as well without having to worry about port-tuning. (Is this a silly idea?)

Thank you all for your time and patience
 
#2
Here is the cut sheet from EV that has the design parameters.


This has dimensions and tunings for a variety of TL boxes.


Here’s an old thread where someone lists dimensions on their cab. No guarantee that’s particularly accurate.

Corwin81

Thread 'EVM-15L in a sealed cab'

Has anyone tried an EVM15L(or even a 15B) in a sealed cab? What size was it and how did it sound? Will they work in this application? Right now, I have one in a ported cab(not sure if it's anywhere near close to being tuned right, it just came with the speaker). I was thinking of possibly building an SVT style 1X15 to go under my newly restored Ampeg SVT-100 head. I've already got plenty of plywood for it.

I know it’s not sealed but the TL606 is the classic box for this driver. Probably cheaper and easier to find a used one and put the driver in it. Alternately you can always contact EV directly and they can recommend you something.
 
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#3
Hey, thanks! I actually went through that thread and, while one guy gives the dimensions of one of the cabs he uses an EVM-15L in, and it sounds nice to him, it wasn’t designed for the driver.

I see tons of guys on here saying they use software and calculators to figure out design parameters for a driver specific cab but, they never name it. Do you have links or names of any of these pieces of software or calculators people are using to design enclosures?
 
#4
I believe winisd is used a lot.

WinISD - Linearteam

@fdeck also has his own program I believe, although I’m not sure off the top of my head if it’s freeware and publicly available.

I will note that the folks who do this for a living all seem to express some skepticism about the accuracy of those programs, take that how you will.

Me personally I’d still email Electro Voice and ask for plans, I’m sure they have some.
 
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#5
Hey speak of the devil. Here's the program that I wrote:


It's not the most popular, but handles the basic calculations. The trouble is... it kind of does the opposite of what you want. Rather than telling you what box volume you should use, you enter the design parameters that you want, and it generates the response curves. Then you have to interpret the curves and decide whether you like them enough to justify buying drivers and cutting plywood.

So it's a piece of the design puzzle, but a small one. I don't know if there's a good option out there, for a tutorial that walks you through the design process.

The default numbers in the program are for a speaker that I built. The accompanying article on how speakers work might be good bed-time reading if you don't mind a touch of math. ;)
 
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#6
LuvHz said:
Is there a simple calculator or piece of software I can use where I plug in speaker parameters and it outputs cab dimensions/internal volume?
Click to expand...
As mentioned WinISD is probably your best bet. I put the TS parameters for the EVM-15L in WinISD and it strongly recommended a ported (vented) enclosure. The data sheet from electrovoice (linked in post above) seems to recommend a ported enclosure. I think the EVM-15L is intended to go into a TL606 enclosure, which is ported. Anyway, WinISD seems to recommend a volume of 1.5 to 2 cubic foot for a sealed enclosure - which seems like it's probably correct, but I haven't double checked it. Low end rolloff is down 3dB at 140Hz, which sucks for bass guitar, but might be ok for baritone guitar.
LuvHz said:
I want a sealed cab just because I play baritone guitar, not bass, so I don’t need super extended low end just want more beef/punch overall. (Am I right in thinking this way?)
Click to expand...
The choice between sealed or ported should be left to the driver. Some drivers are intended for sealed enclosures, some for ported. If you put a driver into an enclosure it's not designed for you will not get the best performance from the driver.
LuvHz said:
A perceived side-benefit I see with a sealed cab also is that I might be able to try other speakers in it as well without having to worry about port-tuning. (Is this a silly idea?)
Click to expand...
Every driver has specific enclosure needs. The enclosure needs to match the driver or the driver won't preform well. Putting random drivers into random enclosures is a recipe for disappointment.

I've built several enclosures (not that I'm an expert) and my best advice it to simply buy a good speaker from a reputable company (Mesa, Genzler, etc.) They know what they're doing and 99% of the time their speakers will sound better than what you can build. You're unlikely to produce a good speaker on your first attempt. Designing a good speaker requires building a prototype, testing (with equipment very few people have) in acoustically treated rooms, adjusting port volume, adjusting the crossover circuit, adding and removing batting inside the enclosure, probably building slightly larger and/or smaller volume enclosures, repeating all tests... And you'll also need a moderately well equipped woodworking shop and the skills to safely construct a box with tight seams that won't raddle or look like a high school wood shop project made on Friday. Finding good quality plywood and MDF is difficult (for me).

For recording, I wouldn't even mess with a mic and speaker. Just go direct. Use a speaker sim if you want. It's so much easier.

As much as I like to design and build things, I've found DIY speakers are generally not worth the time and effort. Sorry to be discouraging. But if I had some spare plywood, some extra time, the workshop, the driver, and I didn't need it to sound spectacular - then I'd give it a shot. Otherwise, just buy one. :)
 
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#7
It used to be possible (although not guaranteed) to DIY and get better performance at a cheaper price. Now commercial cabs are as good or better than what you can do at home, and the prices are comparable.

Building cabs (and even more so designing then building a cab) is a great way to learn how to design and build cabs but is almost guaranteed to be more money and time for worse results.
 
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#8
hmm… maybe I will try to find a used OBC115 (pretty sure it’s a TL606 clone), swap the speaker to an EVM-15L, add insulation to bring it up to snuff, and just live with it being ported.

The curiosity of a sealed 115 is killing me but, not if it’s most likely going to come out like crap.
 
#12
agedhorse said:
The EVM-15L is a terrible choice for a sealed enclosure, it was designed specifically to work well in a ported enclosure, properly tuned as their documentation indicates.
Click to expand...
Yeah, this is where my ignorance comes in. I thought the reason for ports was lower bass extension in smaller enclosure and your trade-off was that now you can only use the cab with that speaker, or other very similar speakers.

I realize now that that’s wrong in more ways than one lol.

What made me lean towards the EVM-15L was its good reputation as a guitar speaker.

I have an original TL-806 with an EVM-12L and LOVE it. I also see people use 12L’s in sealed cabs and 412 cabs so I figured “Oh if people do it for the 12, I should be able to do it for the 15 also”

So, what makes a speaker inherently good/bad for either a sealed or vented enclosure?
 
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#13
O.P.,

I'd suggest your checking into the T.B. Classifieds.

There's sealed, ported, rear ported, used 115 cabs from every manufacturer you can think of for prices I doubt you could come close to matching by DIY.

A few weeks back, there was a 115, Mesa Roadready cab, very good condition, loaded with a EV 15" driver, $300.00.
("I think", the Roadready cabs are based on the TL design.)
 
#15
Balog said:
It used to be possible (although not guaranteed) to DIY and get better performance at a cheaper price. Now commercial cabs are as good or better than what you can do at home, and the prices are comparable.

Building cabs (and even more so designing then building a cab) is a great way to learn how to design and build cabs but is almost guaranteed to be more money and time for worse results.
Click to expand...
I think the exception is if you're looking for something that the market doesn't offer. Those exceptions may be rare. But with that said, I'll match my 1x12 and 1x8 designs against anything that was on the market when I designed them. But they are not general purpose bass guitar cabs. And they're not my first designs. My noobie mistakes are in the landfill. ;)
 
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#17
fdeck said:
I think the exception is if you're looking for something that the market doesn't offer. Those exceptions may be rare. But with that said, I'll match my 1x12 and 1x8 designs against anything that was on the market when I designed them. But they are not general purpose bass guitar cabs. And they're not my first designs. My noobie mistakes are in the landfill. ;)
Click to expand...

Very true. Although that’s mostly true if you’re either building off plans or already have experience. And a lot of the use cases for off market stuff like the BFM horn loaded cabs is solving a problem that doesn’t really exist anymore.
 
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#18
Balog said:
Very true. Although that’s mostly true if you’re either building off plans or already have experience. And a lot of the use cases for off market stuff like the BFM horn loaded cabs is solving a problem that doesn’t really exist anymore.
Click to expand...
Indeed, my past failures are my experience. Also, I have expertise in related technical fields, so it wasn't all that hard to bring myself up to speed.
 
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#19
If you build it, you will learn (something)

as stated, DIY won’t be cheaper but maybe you’re going for a specific aesthetic or just want a new hobby/craft project.

I believe eminence publishes the box volumes for sealed/vented.

Good luck and remember to have fun! Without understanding the math/transfer functions you’ll be relying a lot on your ears and don’t expect to squeeze every once of performance or even close to it.
 

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