First speaker project- Suitcase enclosure

[JimiTwoShoes]

Hi all, thanks for the great resource here.

I will be building my first speaker project and would greatly appreciate any help along the way.

To get started, this is what I would like to do:

Suitcase enclosure
- dimensions TBD but probably normal vintage suitcase size (smaller than modern suitcases)
- sealed enclosure
- reinforced

Speaker array
- I want this to be aesthetically impressive, and will be using 3 or more drivers. I am interested in dual woofer designs.

Performance
- I am a filmmaker and this will be used as a "boombox" on set to keep the energy up between scenes.
- Should be able to get loud
- Will play mostly rock music
- Needs to be portable (less than 40lbs)
- Battery-powered is a huge plus but not necessary if it sacrifices above performance needs

* This is my first DIY speaker project so I want to adhere to the ethos from Darren Kuzma's "Jubilee" project..."wherever difficulty could be avoided without significantly compromising the acoustic performance, it was."
*I also need to keep budget under $700


Cheers! First step for me is to buy the suitcase. I will check back in and keep this thread updated with pics.

Any thoughts/ advice/ tips as I get started?

[HareBrained]

The suitcase idea is novel but limiting. Are you trying to avoid cutting wood or something? You'll probably need to fiberglass the inside of the case to increase the rigidity and hopefully decrease the resonances.

Here are some things to think about:

For some easy but very nice PA systems check out Bill Fitzmaurice's website. His designs will give you enough sensitivity to have a loud system that can run off of a small, battery-powered amp. And there is a company that is offering some of Bill's designs as knockdown kits, meaning you don't have to cut anything.

You may want to cross-post into the commercial/pro forum since what you're asking for would fall into their realm. Depending on the size of the case, you may be able to squeeze an Econowave into it. Search for it and you'll find several great options, and if you prefer, the cabinets can be bought from PE.

Just so you know, one suitcase will be only one speaker. Mono, not stereo. Creating a divider would be very difficult. And if you're wanting a 3-way, you'll need to use a sealed midrange driver, whether that's a cone or a dome will be up to you.

Regarding power, there are many options. The Sure class-D amps would probably be the best. If this is going to be driven by an MP3 player, make certain you select an amp that will accept speaker/line-level inputs, or expect to use some kind of preamp.

The volume of the case will dictate what woofer you'll be able to use. Unless you decide to use a dipole, H-frame construction. This would mean no "enclosure". You put a driver into each half of the suitcase and then open it up and stand it on it's end. You won't get any significant bass from this setup but it will play just fine.

[6thplanet]

"Jimmy Two Shoes" ?? Is this a reference to a certain Dead Milkmen song?

[Pete Schumacher ®]

My very first experience with stereo back in the '60s was from a suitcase stereo my mom bought for us kids to play, so we wouldn't use her Magnavox console. (I owe all my DIY audio efforts to her really.) One suitcase held the record player and amp. Another suitcase held the stereo speakers. The hinge was such that you could separate the two halves of the speaker suitcase and set them apart from one another. They looked EXACTLY like Samsonite luggage.

[davepellegrene]

Here is a link to a set up similar to what you are wanting to build. I built this to take down to my dock to play music. I mostly listen to Rock. It is built with PA drivers for high efficiency. It is driven by a small automotive amp using a self contained battery. I tore apart a suitcase to get the slide out handle and the wheels. It plays very loud and I have run it for eight hours two days in a row and the battery was still fine. It recharges overnight with a wall charger. As has been mentioned I don't think an actual suitcase would be strong enough.

Take a look it may at least give you some ideas and if you want any details on the component let me know.

Dave

[JimiTwoShoes]

Are you trying to avoid cutting wood or something?

No just think it would be fun and an easy way to carry it around. I'm willing to do whatever to make it rigid.

@HareBrained- thanks for all the additional links and suggestions, will take a look.

@Dave- that is really nice and I'll take a closer look at the design. I need something a bit smaller. Something I can pick up and move from room-to-room.

[JimiTwoShoes]

By the way, as I was researching this project, I came upon this site, which offered some inspiration:

http://blog.theboomcase.com/

I don't know much about the construction of these speakers but I inquired about the Monster Masher (about half way down the page) and was told that it uses Vintage Pioneer FB CS-99a speakers upfront and Aura speakers on the side.

It is a 400watt system and the dimensions of the box are 25x20x14

It looks to be built into an old steamer trunk.

Edit: here's a direct link to the Monster Masher, with more info...
http://store.theboomcase.com/monster-masher

And here's another design I'm interested in....
http://store.theboomcase.com/monster-gator

I assume that the amount of speakers is more for aesthetic reasons- something I'm inclined towards, but I don't want to negatively affect performance.

[fbov]

Having built something along these lines...
http://techtalk.parts-express.com/sh...d.php?t=225559

The key factor is speaker sensitivity. Simply put, 3dB of sensitivity is worth 2x amp power, and reduced amp power translates into smaller, longer-life battery and reduced weight as well. Appearance is another matter, and one I leave to you.

You can go with pro drivers, and a short waveguide on the tweeter would probably fit in a suitcase, but you'll be building a 2- or 3-way system. I didn't find pro drivers that fit my application. That's one reason I used a high-sensitivity full-range driver with a simple contour circuit. For your application, if this approach sounds interesting, I'd suggest the larger PS220, primarily to take advantage of your (presumably) larger suitcase volume to get more bass. Simulating a PS220 in ~2 cu ft gives me an F3 of 50Hz, and 105dB at 50Hz with 20w RMS. You'll get 8 hours from a 7AHr gel cell, and save the weight of a deep cycle battery.

Sensitivity, sensitivity, sensitivity....

HAve fun,
Frank

[JimiTwoShoes]

Frank, thanks for the info and the link to your project. Yes, I am also trying to make something like a "super boom box." I will dig through your project in more detail.

I may be getting ahead of myself here but I bought a case....


The dimensions are 30x20x9

It is Pre-WW1 and it is in excellent condition. It is constructed out of thin wood. I will take more detailed shots soon.

[JimiTwoShoes]

These are the basics that I have learned so far...

The volume of the box is a little over 3 cubic feet. So the woofer I choose needs to have a VAS less than that.

And I need to have a crossover to send separate frequencies to my tweeters, mids and bass.

And to keep weight down, I should get drivers that are very sensitive... sensitivity= smaller amplifier= smaller battery= less weight.

And I should fiberglass the case for rigidity.

[Chris Roemer]

These are the basics that I have learned so far...

The volume of the box is a little over 3 cubic feet. So the woofer I choose needs to have a VAS less than that.

* * Box volume is also affected by Qts (this can sometimes be the more important number of the two). Go to "Resource Index" at the top of this page, then find the Woofer Selection Guide. You cn sort the column by cabinet volume (Cb or Vb), then look for a volume close to yours (or smaller). You can always partition the box off internally.

And I need to have a crossover to send separate frequencies to my tweeters, mids and bass.

* * True. I'd shoot for a 2-way in your case. It will be cheaper, lighter, smaller.

And to keep weight down, I should get drivers that are very sensitive... sensitivity= smaller amplifier= smaller battery= less weight.

* * I wouldn't worry TOO much about that. The $20 Lepai amp that's on sale is VERY small, and VERY light, could easily run off a smallish 12v battery, and will drive even 80'ish dB speakers fairly well.

And I should fiberglass the case for rigidity.

* * Probably. It's more effective to brace wall to wall than to try to make a rigid shell.

[JimiTwoShoes]

Got side-tracked in the weeks before Xmas but I'm back on the project. I am still wrapping my head around terms...apparently I had VAS confused with Vb.

When I start selecting drivers, how do I calculate the proper Vb for all of them combined? Do I simply add up the required Vb for each?

[Chris Roemer]

Got side-tracked in the weeks before Xmas but I'm back on the project. I am still wrapping my head around terms...apparently I had VAS confused with Vb.

When I start selecting drivers, how do I calculate the proper Vb for all of them combined? Do I simply add up the required Vb for each?

Again, a 2-way will be sufficient for your needs. If you need more woofer area, use an MTM (single tweeter, double woofers). The tweeter is sealed so it doesn't require any internal volume. 2 woofers need twice the space as a single.

Go to www.linearteam.org and get the free WinISD (it's easier to start out on the "beta" version, not the "Pro - alpha" one).

[JimiTwoShoes]

Thanks for the link to the program...unfortunately, it doesn't run on a Mac. Maybe I'll try to get my hands on a PC.

Again, a 2-way will be sufficient for your needs.

I want this project to sound really good. Also, I have to admit, part of my "needs" are aesthetic. I want this to be visually impressive.

I would like to see if I can make something like this work...
- 1x 15" woofer
- 2x 5" or 6.5" mids
- 2x tweeters

I know it's overkill and complicates things (including having a 3-way x-over) but I want this thing to go BOOM when you listen to it...and when you look at it.

I am narrowing down my driver list and will provide models soon to see if they'll work. I am looking for high-power, high-sensitivity, 8ohm drivers.

[JimiTwoShoes]

I'm looking at this for my single woofer in the middle...
http://www.parts-express.com/pe/show...number=292-415

And two of these mids in the lower corners...
http://www.parts-express.com/pe/show...number=292-204

Still looking for tweeters to go in the upper corners.

[morris]

The vas and qts values of the woofer you linked at are so high it would require a very large enclosure--putting it into you box will probably make EVERYTHING you listen to it boomy.. I agree that you should look into doing a 2-way instead or use a full ranger.

Look at these:
http://www.parts-express.com/pe/show...number=292-430
or
http://www.parts-express.com/pe/show...number=295-346

Going full range will eliminate the need for an expensive XO

I say listen to what the midrange members and senior member here. Most of them are really trying to help and giving you great advice.

[JimiTwoShoes]

The vas and qts values of the woofer you linked at are so high it would require a very large enclosure--putting it into you box will probably make EVERYTHING you listen to it boomy..

I guess I don't understand how VAS relates to everything...I've been going off of Vb and yes, I see now that the Vb for that driver is greater than my enclosure.

I agree that you should look into doing a 2-way instead or use a full ranger. Going full range will eliminate the need for an expensive XO

I hear this loud and clear and I am saying that I don't want to go this route. I want a bunch of speakers and cost is not- and has never been- one of my criteria (within reason).

Can anybody help me design something that has five speakers:
One giant woofer, two mids, and two tweeters.

What about this woofer? It has a smaller Vb (2.15)...
http://www.parts-express.com/pe/show...number=292-415

[901Fixer]

Really cool project! The case you have chosen is plenty big and that's a good thing. You have a big budget, what about a time frame? The learning experience can take awhile.
A 12 volt DC system like found in a car would limit you somewhat power wise and run time but would be more mobile. It's gonna get heavy regardless.
Will you always have a place to plug it in if you didn't go 12volt DC?

The options are just running thru my head. You are gonna modify that case so much it's almost just gonna be original on the outside. Might be better off building a plywood case and attaching all the hardware and trim to the outside to make it look like a suitcase.

How 'bout a single large woofer in the center, maybe 10" and three speakers on either side running vertically from top to bottom. This would be an MTM with a woofer in the middle. Should look nifty, sound great, more easily compartmentalize the inside,........

[901Fixer]

I guess I don't understand how VAS relates to everything...I've been going off of Vb and yes, I see now that the Vb for that driver is greater than my enclosure.



I hear this loud and clear and I am saying that I don't want to go this route. I want a bunch of speakers and cost is not- and has never been- one of my criteria (within reason).

Can anybody help me design something that has five speakers:
One giant woofer, two mids, and two tweeters.

What about this woofer? It has a smaller Vb (2.15)...
http://www.parts-express.com/pe/show...number=292-415

A giant woofer is gonna need more air space than the 3 cuft your case has. I do like the idea of lotsa speakers, 5 or more.
Who is gonna be building this, you? Do you have wood working skillz etc. ?

[JimiTwoShoes]

Sorry, meant to link this one...
http://www.parts-express.com/pe/show...number=290-338
It requires less than my Vb.

And thank you 901Fixer for the encouragement.

The design I'm going for currently is one large woofer (hopefully 15") in the middle of the case with two mids in the lower corners and then two tweeters in the upper corners.

I will reinforce the case with fiberglass or wood braces if necessary.