Introduction to designing crossovers without measurement

[TimA]

I find it's sometimes worthwhile to replace the tweeter L pad attenuation with a simple series resistor and resize the other components in the tweeter section to compensate. Result, a smaller capacitor which can be of better quality. Just a suggestion.

 

[jmascreen]

I can try that

 

[jmascreen]

How much could be the difference between a
Jantzen Audio - 33.00uF 100VDC Electrolytic Non-Polarized Capacitor
&
Dayton Audio DMPC-33 33uF 250V Polypropylene Capacitor

Which one should be good for crossover use?

 

[AllenB]

They will be close to the same. Either would be acceptable to use.

 

[TimA]

Tolerances are tighter with polypropylene, life span better too, but I wouldn't rule out electrolytic in the low pass section. I'd never use it in the HP section though.

 

[zeko]

Great tutorial.

 

[zeko]

what if we choose two different frequencies. for example for bass 2500hz, and for tweeter 5800hz. where in that case will the point of intersection be and what will the amplitude look like?
Thank you

 

[AllenB]

The halfway point would be 3800Hz, but this would only be half way between two similar filters. There will be some variations due to the drivers not being equal to begin with.

The result will probably be a dip in the response, unless you are using shallow filters. Also the polarity of the tweeter which you choose might not be the same as if you were using closer rolloffs.

 

[jmascreen]

How is the phase? How to interpret phase?

 

[AllenB]

When you filter, it changes the timing within the wave. It is necessary to make sure both drivers are working together.

 

[jmascreen]

So from the graph which i posted earlier, is both drivers are in phase? Also when i revert the polarity of both drivers the phase dots comes down

 

[AllenB]

So from the graph which i posted earlier, is both drivers are in phase?

Yes.

Also when i revert the polarity of both drivers the phase dots comes down

This doesn't matter. Left and right should be the same.

 

[jmascreen]

Thanks

 

[jmascreen]

I have implemented this crossover and satisfying initial results. Only thing bothering is the cone movement due to inverse polarity it going in, does it affect the performance or low notes power?

 

[TimA]

Inverse polarity has no effect on the amount of cone movement. In a vented design the tuning frequency of the port does though.

 

[jmascreen]

Ok thanks also a slight ringing has been observed from.these tweeter, any mods to fix it?

 

[TimA]

You will need to describe the ringing in more detail I think.
If the inverted polarity cone movement bothers you, simply reverse the connections to both drivers.

 

[jmascreen]

Ringing in sense somewhat metallic kind of sound bit harsh

I am ok with the reverse polarity its giving me very good low ends

 

[TimA]

The first thing to try is to reduce the tweeter level slightly by adjusting the resistor values.

 

[jmascreen]

Yes I did that and now the tweeter is almost 80db and still the ring is evident more in instruments like guitar etc let me keep it running for some time may be the burn in of drivers and crossover components

Also i am used only silk dome till date and this is fabric dome so i may also need burn in