[dewar]

Hi. I'm hoping someone can help me with one of my first diy projects. I'm wanting to add a B&G Neo3 ribbon tweeter to the back side of my Visaton B200 open baffles.

I want to high pass the Neo3's at 10k. The guy(Danny at GR Research) that is selling me the tweeter is sending me a 1uF and a 2uF capacitor to use for the filter. He says to try both and then a combination of the 2 to see what sounds better.

My question is, is it possible to predict the roll off point and the steepness of the slope? (or, could someone please take a stab at this for me:))

Specs are here: http://www.gr-research.com/pdf/NEO3pdr.pdf

Is it possible to have a 2nd or 3rd order slope or is 1st order recommended?

Also, as far as I've gathered, a capacitor is inserted in the positive wire of the speaker cable, just cut the wire and drop in. Is this correct? Also, if one was to try 2 caps are they run end to end or in parallel?

Many thanks for any help on this,

Bevan

[Dougl]

I want to high pass the Neo3's at 10k. The guy(Danny at GR Research) that is selling me the tweeter is sending me a 1uF and a 2uF capacitor to use for the filter. He says to try both and then a combination of the 2 to see what sounds better.

The BG NEO3 has a flat 4 ohm impedance.  Its the only speaker I know of that the crossover calculators scattered about the web will do a reasonable job with.  http://www.mhsoft.nl/spk_calc.asp
looks like it may work for you.

Is it possible to have a 2nd or 3rd order slope or is 1st order recommended?

  A second order filter would require an inductor.  A Third order would require 2 caps and a coil.  Try it first order and report back.

Also, as far as I've gathered, a capacitor is inserted in the positive wire of the speaker cable, just cut the wire and drop in. Is this correct? Also, if one was to try 2 caps are they run end to end or in parallel?

Yes, just insert the cap in one leg.  2 capacitors are in Parallel.

My question is, is it possible to predict the roll off point and the steepness of the slope?

  The Steepness of the slope will be 6 db per octave, IE first order.  With 2 Mf, the tweeter 3db high pass will be about 20, 000 Hz.

[dewar]

Thanks Doug. Thats just the king of website I was looking for to get on top of this stuff.

Did you mean uF when you typed Mf or is that something different?

Before I start shopping around for parts here in Australia could I ask what brands are generally considered audiophile approved?

thanks for the help,

Bevan

[Dougl]

Did you mean uF when you typed Mf or is that something different?

Typo 

Before I start shopping around for parts here in Australia could I ask what brands are generally considered audiophile approved?

For experimenting, I use inexpensive metalized polypropylene.
Dayton markets one that is attractively priced in the US.  I would look at the Solen, but consider other polypropylene caps, based on price.  At the higher price points, many people have their favorites.  I haven't tried enough of them to make a recommendation.  YMMV.

Doug