Making a two way

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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 :
An externally hosted image should be here but it was not working when we last tested it.


-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:
An externally hosted image should be here but it was not working when we last tested it.


-Piezo Tweeters which small horn (of the same baffle set)
Graph of Impedance
An externally hosted image should be here but it was not working when we last tested it.


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 ?
 
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
 
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
 
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
 
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