Building DIY Speakers on the cheap

[Phatman91624]

Hey,
I got turned on to the Partsexpress NSB buyout speakers by a thread on another forum . So on impulse (can be a bad thing, I know) I bought eight of them and some tweeters in hopes of making a very cheap, decent set of what will more than likely become shop speakers. Here are the links to the drivers:

Woofers (if you can call them that )
Tweeters

The tweeters are pretty bad, I know. But I have some ELF 1.5's (no tweeter) and don't notice too much to be lacking from the music, so I figured I would just buy some cheap speakers (staying with the project theme) and see if I could integrate.

I figured I would either put these in a TMMMM or MMTMM arrangement. I came up with some manageable dimensions and found I could get a maximum box volume of 1.125 ft^3, this will be ported to around 60Hz.

At first I was not going to include a crossover of any kind, but seeing as I've never designed my own crossover (only built them from schematics included in designs) I thought that this would be the perfect project to start the learning process with, something with few reprecussions if I screw it up.

My main questions are these. Any input on the design I have come up with? Any suggestions on what to change about it? Second, as far as a crossover goes what do you guys reccomend (remember these are meant to be a very cheap project, I have much larger things on my plate at the moment that require most all of my funds). Third, I think I figured out how to wire these to a 7.2 Ohm load, but I could be completely off base, I will include a picture If I can, so you guys can tell me if I'm doing it right.

http://web.engr.oregonstate.edu/~hathewam/post.GIF
Ok, here's the very crappy picture of the wiring. Basically I split the woofers up into groups of two. Two 8 ohm woofers wired in parallel, and two in series. The two sets of woofers are then wired in parallel with each other giving I think a 3.2 ohm load. This is then wired in series with the 4 ohm tweeter to give a 7.2 ohm load. Does this look right? Thank you very much for any input or advice you can give.

Mike

[Bill Fitzpatrick]

You don't wire a tweeter in series with a woofer unless you are using a series crossover.

[VeZeSS]

I would most likely do it like this:

"Crossover"

Tweeter wont survive strong bass notes W/O XO.

[Phatman91624]

Ok, changed my plans a bit. Going to wire two sets of two woofers in series, ill then parallel the sets of woofers together, and parallel the tweeter with that. For crossover duty I'll just be using an inductor and a capacitor. Does this sound like a good plan for you guys? Thanks.

Mike

[sreten]

I finally designed and built my first crossover!
http://diyaudio.com/forums/showthrea...967&highlight=


might help somewhat.


Also do a search on "buyout" you may find more.

sreten.

[chipco3434]

These are some speakers I built with the drivers mentioned in your first post.

The Pioneer speakers are the best drivers on the planet for $.87 ~ actually about $1.25 when you figure the freight. There isn't much to them after 200 Hz, but I am running them with a powered sub. In an array, the sound is absolutely remarkable. You hear things that you didn't ever hear on CD's and suddenly it becomes very apparent that some CD's (that used to sound OK) aren't even worth listening to.

In the first iteration, I used the Onkyo tweeters. I was dissatisfied with their sound. But, I have not returned to tweek impedance and crossover. The second iteration used Dayton ribbons. I am very happy with the sound of the ribbons. The second iteration uses a second order Butterworth at 5000 Hz.

In both cases the construction is open baffle. After comparing to my boxed speakers (JBL's and Klipsch), I can't go back. The other benefit is that it greatly reduces the cabinet work.

Take a look.

http://www.diyaudio.com/forums/showt...688#post337688

http://www.diyaudio.com/forums/showt...532#post368532

[Jim85IROC]

It was interresting to re-read the two threads that Sreten posted links to. It's amazing how much I've learned in such a short period of time.

Anyway... I would suggest that people read the 2 links that sreten provided in reverse order. Read this one first:

http://diyaudio.com/forums/showthrea...967&highlight=

then this one:

I finally designed and built my first crossover!

This will take you through the evolution of my crossover design. I just posted my latest crossover in the second thread I linked (the first one sreten linked) and will be hopefully listening to it tonight. I played it on Monday for the first time, only to find that I soldered the inductor on the low pass circuit incorrectly, effectively creating an open circuit on the NSBs. Hopefully by tomorrow I'll be able to post listening impressions.

[Lusso5]

Originally posted by Phatman91624
Here are the links to the drivers:

Woofers (if you can call them that )
Tweeters

I figured I would either put these in a TMMMM or MMTMM arrangement.

Mike

Before you start to build, take note of the sensitivies of your drivers:

The tweeter is 4 ohm rated at 85 dB 2.83V/1m.

The woofer is 8 ohm 86 dB 2.83V/1m

1 watt/1m: 82db (tweeter) / 86db (woofer).

I would look for another tweeter...

[Jim85IROC]

Originally posted by Lusso5


Before you start to build, take note of the sensitivies of your drivers:

The tweeter is 4 ohm rated at 85 dB 2.83V/1m.

The woofer is 8 ohm 86 dB 2.83V/1m

1 watt/1m: 82db (tweeter) / 86db (woofer).

I would look for another tweeter...

It sounds like a perfect match once he incorporates BSC into the woofer.

[Lusso5]

Originally posted by Jim85IROC

It sounds like a perfect match once he incorporates BSC into the woofer.

He mentioned wanting to do a TMMMM/MMTMM. Four woofers would give him around 92db (woofer).

That is a 10db gap.

If I had to use these two drivers, a TM would be all I'd do, and I wouldn't bother with BSC, due to the sens ratings.