[beat]

Hey guys,
I bought all the stuff to do my car audio system about a year ago already. Well now I am ready to start hooking it up. I'm basically wanting to do a sort of crossoverless line array across my dash with some 3 inch full ranges. Here is the exception. I want to put a little 3/4 inch neodymium silk dome in the mix. Somehow I arrived on putting a 12uf cap in front of my tweeter as a simple filter. Am I on the right track? Is this enough to keep it protected?

Thanks y'all.
Beat

[*Scotty*]

Before your question can be answered it would be helpful to know the impedance of your tweeter.
Scotty

[beat]

Ah.. 6 ohm nom

[*Scotty*]

beat,you might want to use a capacitor of 6uf. This would give you a cross over of about 4400Hz at 6dB/oct electrically which might be adequate depending on the power rating of your tweeter and how loudly you play back your music. You  should probably mount your array on board and test out how it sounds in your car before you do anything of a permanent nature to your dash.
Scotty

[beat]

Will do Scotty,
That is actually what I am up to right now. I just wanted to make sure my cap value was in order before I ruined anything. So if a 6 gives me about 4400hz a 12 should be about half that giving me around 2200? Maybe a bit low but I'll see how it sounds and go from there.

Thanks for the feedback.


For the record, my dash is really just a sheet of walnut veneered plywood. Nothin fancy.

[*Scotty*]

beat,remember that a 6dB/oct rolloff rate is very slow and your 3/4in. tweeter is not a midrange driver. At the very least you will probably encounter significant levels of distortion from this shallow a crossover design if not damage from this choice of frequency and cross over slope. I would not cross over a 3/4in. tweeter this low at this slope and expect satisfactory results.
Scotty

[S Clark]

Also, realize that a first order crossover usually throws the tweeter out of phase with the woofers resulting in unwanted signal cancellations.  It sounds like you could use a second order crossover to get some extra protection for the tweeter.  You can get close by looking at the X-over tables at Chokes.com.  For what you are describing, a cap and a coil may be all you need.

[beat]

beat,remember that a 6dB/oct rolloff rate is very slow and your 3/4in. tweeter is not a midrange driver. At the very least you will probably encounter significant levels of distortion from this shallow a crossover design if not damage from this choice of frequency and cross over slope. I would not cross over a 3/4in. tweeter this low at this slope and expect satisfactory results.
Scotty

I gotchya. Once the partsexpress website is up again I can see on a graph where they start to break up. 2200 is kinda low though eh? I'll bet the 12uf would be pushing it. I forgot about the phasing issue. I have a handful of other caps and coils tucked away somewhere. I think I have something more in the ballpark. I'll post my results as I go. Hopefully its acceptable with just a cap. Chances are I wont be able to hear anything in this little beast anyway.

thanks again, Beat

[art]

You have not taken into account the resonant frequency of the tweeter, either.

Pat