Calculate crossover by driver actual impedance (resistance) or spec?

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I have a pair of vintage Jensen H222 coaxial driver. Since they are more than 50 years old, I am thinking to update its crossover. The speaker is stated as 16ohm so I assume the tweeter and woofer are each 16ohm by design. They are designed to crossover at 2KHz. When I measure each of the tweeters and woofers individually, they are about 13-14 ohm each. So my question is when I calculate the crossover, do I use the actual measurement of 13.5 ohm or stick with the 16ohm by their design?
 
There are a few reasons. First I want to by pass the attenuator. Second, I hope to improve the sound with some good quality cap. The stock crossover should be a first order and I am thinking to test it with a 2nd order to see if it will also improve the sound.
 
1)
by pass the attenuator
what attenuator?
2) *if* an attenuator was fit for the tweeter, that is common practice both to match its sensitivity to that of the woofer and also to somewhat protect its delicate voice coil, just don't mess with it.
Or your speaker will be incredibly piercing and shrill for some time, then incredibly dull (after the Tweeter burns) .
3)
I hope to improve the sound with some good quality cap.
Define "improve" :)
Best case: suppose the original cap had very high ESR, think 3 ohms for example.
The speaker was developed and equalized with that cap; you put a different properties one and you mess with the frequency response.
Only justification for replacement would be if it were a NP electrolytic, which would be very dry by now, but I suspect it had a paper in oil one, or something similar.
Now if you think that a highly promoted one can add some not very defined magical properties (soundstage/graininess/blacker background/smoothness/transparency/whatever) well, think again :)
4)
The stock crossover should be a first order and I am thinking to test it with a 2nd order to see if it will also improve the sound.
Check first, it might have a 1st order one, a second order, whatever.
Don't guess.
Supposing you "upgrade" by going 1 stage higher, hope you don't forget doing so will increase phase shift at crossover frequency and might force you to invert polarity of one of them, usually the tweeter, on penalty of having a deep hole at the crossover frequency.
Again, define "improve" first, it might backfire, as they say the Devil is in the details.
 
will you use an electrolytic in series with a tweeter?
May be... may be not... perhaps as a "protection", so its value will be VERY large.
I'm using a three way active xover system, so I don't care about passive xover components, but my old speakers were passively crossed using a NP electrolityc cap first and a poliester one after some time... and I wasn't able to hear any change in the sound...
 
Thanks for Benb pointing out that the measurement is only the DC resistance and not the actual nominal impedance.

I may have used the wrong term when I refer to an attenuator. It is actually just a switch to control the level of the HF. I don't feel it is necessary for my listening to adjust the HF level so I want to bypass it. The tweeter and woofer should be designed to match each other sensitivity. The manufacturer provide plan for user to build different cabinet so I believe the switch is for adjusting the HF level when fitting with smaller box. I am using the driver in an open baffle.

I read that the H222 coaxial have a equivalent separate woofer and tweeter from here,
Anyone re-capped a Jensen H222? | Audiokarma Home Audio Stereo Discussion Forums
From that post you can also find the schematic of the crossover designed for the separated version of tweeter and woofer which have a 2nd order filter. The H222 coaxial that I have should only have a single cap and coil. I cannot see the exact parts as it is potted but I can see the shape of mainly one coil in it.
Yes it is probably using a paper in oil cap but I think using a new good quality cap won't do anything worst than a 50 years old cap. I am not planning to use any cheap electrolytic. And it is probably best for me to build my own crossover for my test on improving the sound with all new parts so I can just leave the old crossover intact if I want to restore it.
 
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