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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Subwoofer FUD Forum Archive => Topic started by: Louie Warren on April 28, 2008, 02:49:35 pm

Title: DIY compact sub cabinet
Post by: Louie Warren on April 28, 2008, 02:49:35 pm
I want to build a compact sub with a 15" driver.  Our singer has some EV Eliminator i 18" subs and thought of a similar design.  Are there any good plans on the net?  Things to think about?   I don't want state of the art... it would be a drum monitor sub for my kid.
Thanx!
Title: Re: DIY compact sub cabinet
Post by: Jeff Babcock on April 28, 2008, 03:25:40 pm
There are free plans on some manufacturer websites for standard front load cabinets based around the speakers they build, you might also try looking around at speakerplans.com.  Or if you don't really want to build (just trying to keep $ low) maybe put a WTB ad in the marketplace section here.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 28, 2008, 03:53:14 pm
Jeff Babcock wrote on Mon, 28 April 2008 15:25

There are free plans on some manufacturer websites for standard front load cabinets based around the speakers they build, you might also try looking around at speakerplans.com.  Or if you don't really want to build (just trying to keep $ low) maybe put a WTB ad in the marketplace section here.


Thanx!  I checked out the Eminence site and they have a program that will allow you to design your own based on a speaker.  The HD 15 folded horn on speakerplans.com seems to fit my needs... I will continue to search.  If I find anything exciting, I'll post it here.  Thanx!

L
Title: Re: DIY compact sub cabinet
Post by: Jeff Babcock on April 28, 2008, 04:28:02 pm
If this is to be a drummer's monitor sub, then horn-loaded subs are probably not the best solution as there is some small delay introduced by the horn path length of the cabinet, anywhere from roughly 5-10ms could be introduced depending on the design.  While I personally prefer the efficiency of a horn sub for general PA applications, for a drummer's sub I would prefer front loaded.  
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 28, 2008, 04:40:22 pm
Jeff Babcock wrote on Mon, 28 April 2008 16:28

If this is to be a drummer's monitor sub, then horn-loaded subs are probably not the best solution as there is some small delay introduced by the horn path length of the cabinet, anywhere from roughly 5-10ms could be introduced depending on the design.  While I personally prefer the efficiency of a horn sub for general PA applications, for a drummer's sub I would prefer front loaded.  


Didn't think of that... I'm a guitar player Embarassed   Ok... my main issue is a small foot print... right now the sub is an old Peavey 1516 Bass cabinet (loaded with an Eminence Kappa Pro LF)... I don't need the mid speakers or the crossover... it all fits under my JBL TR-105 for the mid-highs.  My kid plays in a punk band.  I also use this for a country project I play with, but the drummer for that is working going in-ear/ButtKicker, so I can kinda tweak it for my kid.  I need a small footprint 15" sub that has at least the thump of the Peavey.  Since I can drag the Peavey around until I find a solution, there is no rush so I want to do it right, but I want to do it with what I have and the only new expense being what is necessary to build the cabinet.
Title: Re: DIY compact sub cabinet
Post by: Jeff Babcock on April 28, 2008, 04:44:24 pm
I would use the Eminence tools to build a small volume box for the Kappa Pro, or use some of the other free design tools to build a box based on the driver specs.  Keep in mind the tuning of the box is VERY important to get right.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 28, 2008, 05:38:21 pm
Jeff Babcock wrote on Mon, 28 April 2008 16:44

I would use the Eminence tools to build a small volume box for the Kappa Pro, or use some of the other free design tools to build a box based on the driver specs.  Keep in mind the tuning of the box is VERY important to get right.


Sounds like a plan... I will definitely check into the Eminence software!
Title: Re: DIY compact sub cabinet
Post by: Marjan Milosevic on April 28, 2008, 05:54:27 pm
just download WinISD from here

http://www.linearteam.dk/default.aspx?download=winisd

it has your driver parameters already inside.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 28, 2008, 06:16:00 pm
Marjan Milosevic(MarjanM) wrote on Mon, 28 April 2008 17:54

just download WinISD from here

http://www.linearteam.dk/default.aspx?download=winisd

it has your driver parameters already inside.


Got it!  Thanx!
Title: Re: DIY compact sub cabinet
Post by: Silas Pradetto on April 28, 2008, 09:24:35 pm
You won't find a good horn sub with a small footprint anyway.
Title: Re: DIY compact sub cabinet
Post by: Phil LaDue on April 28, 2008, 10:21:42 pm
Silas Pradetto wrote on Mon, 28 April 2008 21:24

You won't find a good horn sub with a small footprint anyway.

What do you call a small footprint?
Title: Re: DIY compact sub cabinet
Post by: Rob Timmerman on April 29, 2008, 01:38:57 am
Silas Pradetto wrote on Mon, 28 April 2008 21:24

You won't find a good horn sub with a small footprint anyway.


Define "good".  Define "small".

The JTR Growler and the Danley TH-Mini are both quite compact and are supposed to sound quite good.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 29, 2008, 11:14:30 am
Phil LaDue wrote on Mon, 28 April 2008 22:21

Silas Pradetto wrote on Mon, 28 April 2008 21:24

You won't find a good horn sub with a small footprint anyway.

What do you call a small footprint?


Rob Timmerman wrote on Tue, 29 April 2008 01:38

Silas Pradetto wrote on Mon, 28 April 2008 21:24

You won't find a good horn sub with a small footprint anyway.


Define "good".  Define "small".

The JTR Growler and the Danley TH-Mini are both quite compact and are supposed to sound quite good.


I know it wasn't directed at me, but... I need a new home for my Eminence Kappa Pro 15LF.  It currently resides in an old Peavey 1516 bass cabinet.  It sits under a JBL TR-105 which is the mid-high portion of a drum monitor mix.  I want AT LEAST the "performance" of the Peavey and the size should be no larger than the Peavey.  If it sits under the TR-105 (while on it's feet as a monitor wedge) and does the job, I'll be happy.  Since the Peavey is the benchmark for size and performance it should be hard to do better and more compact...  Very Happy
Title: Re: DIY compact sub cabinet
Post by: Les Webb on April 29, 2008, 01:31:41 pm
Eminence 3015LF neo in a small front loaded cab would be ideal IMO.  Use WinISD to get some box parameters and port length/sizing.

Les
Title: Re: DIY compact sub cabinet
Post by: Iain_Macdonald on April 29, 2008, 01:38:47 pm
Hi,

Eminence have the plans for your driver on their web site. No need to buy their software. The pdf is on the same page as the spec sheet for the driver. If you phone them, they will email you the pdf for the older version of the driver.

Iain.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 29, 2008, 03:11:21 pm
Les Webb wrote on Tue, 29 April 2008 13:31

Eminence 3015LF neo in a small front loaded cab would be ideal IMO.  Use WinISD to get some box parameters and port length/sizing.

Les


Thanx but I already have a Kappa Pro 15LF... would the same parameters work?
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 29, 2008, 03:12:10 pm
Iain Macdonald wrote on Tue, 29 April 2008 13:38

Hi,

Eminence have the plans for your driver on their web site. No need to buy their software. The pdf is on the same page as the spec sheet for the driver. If you phone them, they will email you the pdf for the older version of the driver.

Iain.


I saw spec sheets with charts and figures, but no blueprint or the like...
Title: Re: DIY compact sub cabinet
Post by: Marjan Milosevic on April 29, 2008, 03:45:16 pm
Please guys dont over complicate.

Louie, just build a box wit 170l of internal volume with two holes with 12cm diameter.

That port will tune the box to 40Hz and will give you optimum results for your driver.

Make sure you add enough bracing inside the box to eliminate resonance problems.

Regards
Marjan
Title: Re: DIY compact sub cabinet
Post by: Mike {AB} Butler on April 29, 2008, 03:56:37 pm
Marjan,
You don't say what length of port he should use. If thickness of material only, you need to state what material thickness he should use, such as 12mm or 18mm.
Yes, it's at least THAT complicated.. Twisted Evil
Regards,
Title: Re: DIY compact sub cabinet
Post by: Marjan Milosevic on April 29, 2008, 04:07:50 pm
Just the thickness of the material. 18mm that is.

Very Happy  
Title: Re: DIY compact sub cabinet
Post by: Mike {AB} Butler on April 29, 2008, 04:18:06 pm
Arr. Thanks, man!!  Smile
Title: Re: DIY compact sub cabinet
Post by: Peter Wing on April 29, 2008, 07:49:47 pm
True about the horn loaded subs not being good for time accuracy, but the HD15 has about 16 inches of horn length, its a bandpass horn, and would likely measure at less than 1.5ms of horn delay. Which is fine in my opinion.  
Title: Re: DIY compact sub cabinet
Post by: Marjan Milosevic on April 29, 2008, 08:18:25 pm
HD15 is not a sub. It is a kick bin. Good 80-150 Hz.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 30, 2008, 04:59:19 pm
Marjan Milosevic(MarjanM) wrote on Tue, 29 April 2008 20:18

HD15 is not a sub. It is a kick bin. Good 80-150 Hz.


Isn't that what I want?
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on April 30, 2008, 05:33:37 pm
Another stupid question... can someone explain, in layman's terms, Bandpass vs Sealed vs Vented... I am assuming the sealed is just that with no port and the vented is ported?  I probably know what is what, just not these terms.  Thanx!

L
Title: Re: DIY compact sub cabinet
Post by: John Roberts {JR} on April 30, 2008, 07:27:40 pm
Louie Warren wrote on Wed, 30 April 2008 16:33

Another stupid question... can someone explain, in layman's terms, Bandpass vs Sealed vs Vented... I am assuming the sealed is just that with no port and the vented is ported?  I probably know what is what, just not these terms.  Thanx!

L



I'm not a speaker expert but I'll give it a pass.. First loudspeaker design is the ultimate engineering compromise where you are constantly trading off one characteristic for another. These different box approaches represent different design approaches with their characteristic tradeoffs.

The simplest loudspeaker is the sealed box (aka infinite baffle- while it isn't really infinite) loudspeaker. This is the baseline for performance and still considered the best by some Hifi purists.

The first trade off is the ported cabinet. This trick, adds a hole (port) and uses the rear wave of the driver when combined with the front wave to extend LF response. The compromise is ripples in the passband and faster bass rolloff when it does finally roll off. Another downside is that below port tuning there is no box damping to prevent driver over-excursion.

The bandpass box, is even trickier than the ported output box where it uses a tuned front chamber and back chamber to increase output. These are generally done to increase output efficiency in exchange for extended bandwidth.

The phase and amplitude response of the more complex speaker approaches are less simple but this is generally not considered a big problem compared to getting another another octave lower for given box/driver or doubling the SPL output over a narrower range.

Perhaps a real speaker guy will expand on this (or correct me).

JR

PS: and then there are horns...
 
Title: Re: DIY compact sub cabinet
Post by: Winston Gamble on May 01, 2008, 12:10:13 am
Louie Warren wrote on Wed, 30 April 2008 22:33

Another stupid question... can someone explain, in layman's terms, Bandpass vs Sealed vs Vented... I am assuming the sealed is just that with no port and the vented is ported?  I probably know what is what, just not these terms.  Thanx!

L


Here are a couple site with some definitions.
 http://www.diyaudio.com/wiki/index.php?page=Types+of+subwoof er
http://www.diysubwoofers.org/
Winston
Title: Re: DIY compact sub cabinet
Post by: Tony "T" Tissot on May 01, 2008, 01:24:47 pm
Louie Warren wrote on Tue, 29 April 2008 12:12



I saw spec sheets with charts and figures, but no blueprint or the like...


http://www.eminence.com/pdf/cab-kappapro-15lf-2.pdf

Slightly newer version.
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on May 01, 2008, 01:33:04 pm
Tony "T" Tissot wrote on Thu, 01 May 2008 13:24

Louie Warren wrote on Tue, 29 April 2008 12:12



I saw spec sheets with charts and figures, but no blueprint or the like...


http://www.eminence.com/pdf/cab-kappapro-15lf-2.pdf

Slightly newer version.



Yes, that's what I was talking about... I was looking for something like this:
http://www.geofex.com/Article_Folders/voxamp/voxcab6.gif

A step by step of how to build it... speaker building for dummies if you will.  I'm a guitar player...  Smile
Title: Re: DIY compact sub cabinet
Post by: Mike {AB} Butler on May 02, 2008, 09:08:23 am
Ahh, yes, the good 'ol cut plan.  Cool
Louie,
Here is a step-by-step of some of the basics:
- Obtain materials and drivers. As far as materials for the box, best to use plywood, as opposed to particle board or MDF - I advise against using either for cabinets that will be moved around. OSB can be used.. if you are planning on rat fur covering. Birch ply is best - just be sure that the ply you buy doesn't have another filler wood on the interior layers. It should be the same as the outer veneer.
- Based on material, develop a cut plan that will maximize best use of material actually obtained and minimize waste. Remember to include compensation distances for any special cuts like Dados, Miters, rabbiting, and allow extra depth on the sides, top, and bottom to allow recessing the speaker behond a grille. Adding an extra inch or so is optimum for most designs. In any case be sure to allow for maximum excursion of driver to NOT make contact with grille!
- Cut panels to size with either a table saw, or a circular saw with a staightedge clamped to the work material. If using straightedge, ensure there is the proper compensation distance between edge of plate on saw and saw blade.
- Do any finish cutouts (like speaker cutouts, handles, etc), dados, and other work that can't be done if box gets assembled.
- Assemble box using either a polyurethane or similar glue. Gorilla glue, Sumo glue, and similar produce best results. Use either clamps (best), or tack down with brads or staples. Use screws for any removable panels.
- As far as screws, Speaker should be fastened with T-nuts and machine screws. Pick a large enough diameter. Ditto this method for using a speaker clamp as well.
- Make sure final result is will sealed against airleaks. Be aware that handles, signal connectors, and the speaker fram can allow airleaks to occur. Use Silicon rubber for all non-disassemblable surfaces and joints, and use felt, sponge rubber, or similar material for all disassembled joints, such as speakers, connector plates, handles, and grilles (yes, these will tend to rattle pretty badly otherwise).
- Also, large panels will tend to vibrate. You should use some internal bracing, such as 2X2 or 2x4 in larger boxes, as vibration of a panel means that useful energy is being lost, particularly in subs. Spacing isn't as critical as making sure there is enough. I like to use a rule of thumb of at least one per every 12 linear inches.
Not the complete list! I just don't have time to do ALL of the different aspects..
HTH, and everyone else feel free to contribute what I left out.  Cool
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on May 02, 2008, 02:22:50 pm
Mike {AB} Butler wrote on Fri, 02 May 2008 09:08

Ahh, yes, the good 'ol cut plan.  Cool
Louie,
Here is a step-by-step of some of the basics:<snip>


Thanx!  Now if I can get my procrastinating rear in gear...  Very Happy
Title: Re: DIY compact sub cabinet
Post by: Mike {AB} Butler on May 02, 2008, 03:21:23 pm
Louie Warren wrote on Fri, 02 May 2008 14:22


A step by step of how to build it... speaker building for dummies if you will. I'm a guitar player...  
Mike {AB} Butler wrote on Fri, 02 May 2008 09:08

Ahh, yes, the good 'ol cut plan.  Cool
Louie,
Here is a step-by-step of some of the basics:<snip>


Thanx!  Now if I can get my procrastinating rear in gear...  Very Happy


Well, You now have one.. Very Happy
Go thee forth, and buy thee thine material!!  Laughing
Best,
Title: Re: DIY compact sub cabinet
Post by: Louie Warren on May 06, 2008, 11:21:42 am
Since it's for my kid, I may wait for him to buy the material... otherwise, he can haul that heavy a$$ Peavey around...


Thanx!

L
Title: Re: DIY compact sub cabinet
Post by: Jared Scott on May 16, 2008, 06:03:37 am
Marjan Milosevic(MarjanM) wrote on Tue, 29 April 2008 15:07

Just the thickness of the material. 18mm that is.

Very Happy  


When I run those numbers I get a 61.33 hz tuning, not a 40 hz tuning.

I personally would suggest going 141L (5 cubic feet) with 2 12cm (4.75") ports 21cm (8.25") deep.  That gives you a 40 hz tuning with a nice plus or minus .75 db shelf from 42 hz to 200 hz, about where you want a kick drum monitor in my opinion.