The story of my life: diy speakers (as told by an EE)

[JLC7]

I figure I'd chronicle my first and a half speaker build because a.) I love reading other people's threads and I learn a lot from them and b.) I'll probably learn a thing or two from your comments and unofficially c.) I have nothing to do at the moment.

I'm an electrical engineer so I know a thing or two about electronics. (Ok maybe I know a lot. But I definitely know more than is healthy) I'm a semi-competent wood worker. I can cut things... yeah. But don't expect me to be cutting fine art out of wood anytime soon.

I say first and a half build because I'm re-using drivers I had in my first build but making new cabinets and crossovers. I'll be making bookshelf sized 2-way with vifa XT25TG30-04 tweeters and P17WJ00-08 woofers. The cabinets will be around 15 liters / .52 ft^3 in volume and will be ported and tuned to 50Hz. The drivers will be crossed over at 2.5kHz LR4 acoustic. Crossovers will be designed and modeled with measurements I'll make of the drivers in the cabinets. I'll be using speaker workshop for modeling.

So here's what I got done over the Memorial Day weekend:



MDF is cut for the cabinets. Even with a budget table saw, MDF cuts like butter.
(a large stock sheet of MDF cut into 1/3's fits nicely into the back of a toyota prius, just FYI.)


Must... have... coffee...



I prefer to cut braces with a router and guide. I think they're neater that way... well at least MDF man approves.


I also prefer not to go bananas with clamps. It's glue and screw all the way for me. Besides, I can get 4 cabinets done an hour this way and you can actually move them after they're done.


The dried glue scrapes off easily with my makeshift scraper tool.
I also use it to remove other imperfections like raised MDF fiber from countersinking.



After that the screw holes are filled in and ready to be sanded (at a later time.)

I chose not to roundover the edges of the cabinet even though I have the bit for aesthetic reasons. The baffle is also non-removable because I plan to...


veneer. (boy am I glad that ping-pong table finally got put to good use.)

This is my first time veneering so I'll be testing things out often.


Here you can see the veneer in comparison with 3/4" MDF.

And...


omg it bends! (not so nicely against the grain though)

And finally (for now) here are samples of the veneer with a few staining options.


On the left is 'golden oak' followed by unstained and 'natural.'

Not sure which one I'll go with though.

I'll be sanding the cabinets next. I'll probably veneer today as well. Any tips on where to place the 'seams' of the veneer on the cabinets wo they look ok?

Thanks for dropping by. More pictures to come.

[Luke]

two things.

1. Great work, look forward to seeing the finished product.
2. Try some real coffee

[JLC7]

I'd love to have something like caribou coffee but starbucks is all we have around here. Not even the mom and pop shops exist around here. But enough about me, let's talk about speakers.

Sanded the cabinets smooth this morning. They look...


...exactly like they should.



I did a quick iron on veneer test and it seems to bond strong enough. It's holding up the weight of the MDF. Impressive.

I also have some feathered company overhead in a nest. They must be freaks about diy speakers.... just look at their eyes.



Up next is veneering the cabinets, followed by routing the driver and port holes and rabbeting the edges for the driver flanges.

Actually no I lied, up next is lunch. I'll be back.

[Godzilla]

Thanks for posting your progress. Fun reading! Enjoy your new speakers... subwoofer to follow?

Godzilla

[bastek]

Makes me feel mad for not taking any pics of my diy project last year.
Great work so far, keep posting.

[mazeroth]

Great thread!

[Rodeodave]

MDF-smoke. Don't breathe this!

[Inductor]

JLC7, don't forget to route? (router) recesses first and cut the holes for the drivers after.
By the way, are you close to Baltimore.

[nigelwright7557]

Have you thought about something a bit more exciting than a simple box design ?

1/ How about a bass reflex speaker ? Start with a normal box but have a duct below the speaker to add in the sound from the rear of the speaker.

2/ Folded horn. I have the speaker facing rearwards and have ducts above and below to make the sound go forwards.

Both of these designs are more efficient than the standard box.

[DavidLR]

Hi-

Interesting thread for me because I have a pair of DIY MTMs using the same woofers but with the Vifa D27TG-45-08s for tweeters.

If I had to guess, I'd say you were taking the drivers from your older MTM's, turning them into 4 two-way speakers. Thought of the same thing myself actually, only I'd replace my tweeters, never have been too happy with them. Maybe one of the well regarded but affordable Scan
Speak tweeters

Not much interest in these particular Vifa units anymore it seems. From what I can tell, they are probably 4-5 years beyond their technological prime, all the advanced DIYers have moved on to the latest. But, what the heck, they aren't bad, great for experimenting & learning.

Good luck- I look forward to seeing your crossover design process & final comments.