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Crossover capacitor for AMT4 (Heil Air Motion Transformer)

Oerets

Oerets

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Stumbled along a pair years ago. They both Ohm out at 4.6 Ohms DC resistance. Put a signal to them once since owning to test when still in cabinets. Cabinets were water damaged and drivers were replaced with nice after market ones.

Do have the original crossovers still around. Seeing they were for the AMT4 woofers and thinking of testing the Heil's out now. The OEM crossover was designed for their driver. My question is from my understanding, the calculating of the capacitor's value for a Heil is different then for the common standard tweeter.

If so how is it calculated? Seeing unsure of what driver will end up being used or even have them as a stand alone tweeter.
 
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Typically, the Heil is assumed at "4 ohms" and people will use a 4-ohm Lpad if constructing their own crossover.

Personally, I put them in series with a 4 ohm Mills resistor and assume an 8 ohm load in my calculations. Because the Heils are so efficient, I find the loss of volume to be insignificant and even though I run them with JBL 10" and 18" woofers, I turn them down. I find that they do like the Mills resistors with their superior construction and those are the only resistors I will now use with them.
 
transmaster said:
Mills is all use in crossovers they are the best non-inductive resistor that money buy. Mundorf is my choice for capacitors.
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In addition to the Mills resistors, I use 4.7 MFD Mundorf Evo Oils on the Heils. I also have AMPOHM (0.22 MFD) and Jupiter (0.47) as selectable "by-pass" capacitors in series with 12.5 ohm Mills that can piggy-back on the Mundorfs. Though barely audible, these add "clarity/edge/fill".
 
What frequency for the bottom end is recommended optimum for a 2 way? Just how low is best?

Having the old crossovers will need to dig them up and look it over. It had a switch not a L-Pad IIRC.
 
Oerets said:
What frequency for the bottom end is recommended optimum for a 2 way? Just how low is best?

Having the old crossovers will need to dig them up and look it over. It had a switch not a L-Pad IIRC.
Click to expand...

Optimum? I guess that would depend on what woofer(s) you pair it with.

Yes, the originals used resistors and a selector switch, but if one is going to redo something, maybe "original" is not the best way to go.
 
Thinking a crossover point around 3K for starters. Just wanting to play around with them some. Had heard they were tricky getting the crossover just right. May of been them being louder so needing taming.
 
You heard right and I think that it may have to do with the phasing where the two drivers come together. You can get a nice peak, or dip, depending on the phasing.
 
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