Making a two way

[Zardoz89]

Hi. I'm a newbie that I like to build a baffle for see films , play games, and sometimes listen music in mi PC. I have have four woofers of 6" and two piezoelectric tweeters. I like to use ONLY IT, and not buy other woofers/tweeter of better quality.

I get the Thiel-Small parameters of the woofers using a polymeter, a amp of 40W and mi PC like signal generator.

-Best 6" Woofers (Brand X, that come which my actual 40W+40W Amp)
Rmax Re R0
17,64 3,4 7,74

QTS 0,4
QMS 7
QES 0,42

F1 52
F2 94
Fs 70

Calculated VAS (if i do well) = 20,45 L
GRaph :


-6" Woofers from a baffle set for car (Brand Y)

Rmax Re R0
13,33 4,3 7,57

QTS 1,1
QMS 14,6
QES 1,18

F1 67
F2 87
Fs 80

Calculated VAS (if i do well) = 14,49 L
Graph:


-Piezo Tweeters which small horn (of the same baffle set)
Graph of Impedance


So, my questions is... how I calculate the crossover filters (the crossover frequency), and how pretty well it's WinISD to obtain the size for the baffles. I use to get a baffle of 19,8L which the "bad" woofers, but I compared which a old book of radio, tv and audio electronics and it's says that for a 6" bass reflex baffle, i need nearly x2 size.

Plus I listen that there possible build a subwoofer using two 6" loudspeakers ? How nice works it ? It will sound good if I use my two best woofers for build a "subwoofer" and the other two woofers which the tweeters to make a mid/high baffles and setting a 2.1 audio system ?

[mikje]

Zardoz,
I don't know if you've seen them, but here are a couple of links with a lot of good info. Maybe you can find your answer within them.

http://www.lautsprechershop.de/tools/index_en.htm

http://www.the12volt.com/caraudio/crosscalc.asp#ccc

Mike

[Zardoz89]

The second link, I know it. The other not. Thanks!

But what frecuency i need to use in the crossover filter

[mikje]

Zardoz,

I'm new at DIY speakers too, but I'll answer as best I can.

First, with a piezo, you don't need a crossover. You can use one if you'd like, but it isn't necessary.

I think the crossover frequency, if you decide to go with one, depends on your woofer and tweeter parameters. Without knowing their frequency ranges, I don't know at what frequency you should crossover.

Some folks that use a piezo put a 4 uf capacitor in series with it and are quite happy with that arrangement. You can experiment with different value caps if you have some available; they're pretty inexpensive.

Hope this helps.

Mike

[PeteMcK]

post #6 in this thread will tell you how to connect piezos:

How do these piezo tweeters work?

[Zardoz89]

I was reading about piezos, and I know that are like a capacitor and can be used without crossoover ( I just get fro ma cheap baffle that have it in parallel which the woofer!). But at same time, I read that It best for the woofer and sound quality using a 2º orden crossover filter. Mainly it increases woofer life and sound quality of high tones, because a woofer trying to play 4000 Hz and above sounds sound ugly , etc...

I put the impedance graphs of the loudspeakers, because I not have idea of what freq I need set the crossover to work well and I'm asking help about it

I read that some people put a resistor in parallel o in series which the piezo tweeter

[PeteMcK]

where you say ''baffle'' I think you mean ''box''

to decide on xover freq, we need freq response graphs,

Re: ''a woofer trying to play 4000 Hz and above sounds sound ugly'' - but you've limited your choice to this by using piezos

re:''It best for the woofer and sound quality using a 2º orden crossover filter'' - depends on the combination of drivers, once again we need freq. response graphs to decide this

I'd try the woofer that responds highest with the piezo, - easy (& cheap) to try, and then add a 1st order (coil in series) on the woofer

neither of those woofers will go very low, so no good for sub,
but try them in an EBS alignment in WINISD