Student DIY speaker from scratch

[veruvius]

Hi all,

So I'm in college, and for one of my classes, we have to build a speaker from scratch. We can't spend more than $50 on it. They provide some copper wire, 12 cheap ring magnets, a nut, bolt, and a washer, and a metal plate. My roommate did it last year, and he got some neodymium magnets, used a manilla folder for the cone, and built the housing from maybe MDF and plexiglass. His speaker was the loudest, but one of the least consistent. Oh yeah, it's a contest sponsered by Bose, and they judge based on loudness, consistency, and frequency response. Any ideas on what I can do? I've been doing a lot of research, and I know MDF is one of the best enclosure materials, so I'll probably just get that from Home Depot (which they have, apparently). Should I get some better magnets? The actual speaker is what I wonder about most. Maybe make some port holes in the box? I'm going to try and check out some books while I wait for replies.

Thanks to all that reply!

 

[Rip Van Woofer]

Holy crap. You mean you have to build the DRIVER from scratch?? I assume you're in an engineering program. I certainly hope so because otherwise...yow. Compared to the problems of designing a driver building the box strikes me as relatively trivial.

I'm just a lowly lib arts grad but I know there are books and other sources out there on 'transducer design' which is what applies in your case. Hit your libraries. One recent book I know of is "Audio Transducers" by Earl Geddes. I haven't seen it but assume it is pretty technical.

As far as the enclosure design, Vance Dickason's books are well regarded sources for info. Very popular with the speaker builder hobbyist. But you have to know the Thiele-Small parameters of your driver first to design the enclosure. Meaning you have to build and test the driver first.

Other names to look for as authorities: Joseph D'Appolito, Floyd Toole, Kevin Voecks, Edgar Villchur (deceased), Roy Allison (deceased? Not sure), Henry Kloss (deceased), Ken Kantor, Klipsch (deceased, not sure of first name). Not an exhaustive listing but a start. Find articles and books by those guys and others you will no doubt hear about. Find and buy relevant journal articles and "preprints" authored by them and others from the AES (Audio Engineering Society) website. http://www.aes.org

Finally, I suggest that you also post this query on the Madisound speaker building forum. It is a hangout for advanced speaker building amateurs and even some pros. http://www.madisound.com

Keep us updated. This sounds fascinating. Take pictures of your and others' efforts and post them here!

EDIT: I just Googled "transducer design" (with quotes to return results for the exact phrase) and got several potentially interesting links. I didn't follow up -- that's your job!

 

[veruvius]

Hey, thanks for the reply. Yeah, I'm in the Engineering school at Tufts. I'm actually a chem e, but all engineers here have to take intro to electrical engineering, and the project is to build a speaker. They give us the copper wire to hand wind the voice coil and the permanent magnets to make the driver. I have no idea what sort of speakers get made each year, but I know they end up comparable to speakers on a bad boombox. I'll have to start the work really soon, so I'll let you know how it turns out, and maybe I'll use my housemates camera to show you some pics.

 

[Sheep]

For 150bucks, you could buy a TON of crappy bose speakers, they will be loud in 300Hz-14kHz range.

Seriously, what would Bose know about SPL's, Flat FR's, and Big FR's...


SheepStar

 

[Rip Van Woofer]

Since you're not an EE major my list of resources might be overkill; obviously you won't do miracles in one semester in a class outside your specialty. But it sounds like a great learning experience. Sometimes I miss school when I hear about things like this.

Anyway, hope I was of some help!

BTW, I hand wound some inductors for a speaker crossover once. Talk about tedious. Hope you work out a better way to wind your voice coils!