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Discussion Starter · #1 · (Edited)
As part of the upgrade that I am doing to my 987 audio: BOSE --> Kenwood sat nav & JL xd600/6 amp, but retaining the original BOSE speakers, I have been trying to research the impedence of the speakers to try to avoid frying any components.

Anyway, here is the results of my non-scientific thinkings (thanks very much to c-rizzle for bouncing thoughts on this)

This may not be correct, but it's where I am...

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BOSE Speaker impedance:

I've been speaking to a familly friend who used to be involved in design of audio electronics many years ago, but I would think that the principles are not changed.
He tells me that there are some formulas and fancy ways of measuring impedence, but, if you use a starting point of measured resistance, then, for a low frequency speaker, the impedance will not be a lot more than that measurement. However, a high frequency speaker will be a lot more. The impedance should not be less than the measured resistance though.

So, here's what I now think (note, this is just my guess work/interpretation rather than science):

speakers / resistance measured / frequency / probable impedence / note
door mids & dash tweets combo / 2.5 ohms / mid range / 4 ohm / I guess that the speakers are in parallel and mid frequency means that the impedence will be a reasonable amount more than measured resistance
door subs / 1.5 ohms / low range / 2 ohms / low range speakers' impedance won't be a lot more than the resistance as they never have a very high frequencies
rear tweets / 4 ohms / high frequency / 8, maybe 16 ohms! / as these are high frequency speakers, I think that the impedance will be a lot higher than measured resistance

summary:
I'm pretty convinced that the door subs are 2 ohm, and therefore should not be a problem for my amp. I may, however, try them with a 1 ohm/10 watt resister in series first as this friend is sending me a pair to try.
 

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Did you measure the impedence at the speaker terminals? Or at your amp location in the trunk?
The wiring COULD be adding a little resistance, depending on length & gauge of wire.

the 2 door speakers if they're both 4 ohm speakers in parrallel then technically they should be 2 Ohms, but you're reading of 2.5 is with in range.

I thought actual readings were often higher as the speaker manufacturers quote "minimal load" so you don't mess up your amp.

Maybe someone who's changed their speakers for new ones, can get a part # or something that we can reference for technical data on the speakers.
 

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Discussion Starter · #3 · (Edited)
the resistance was measured at the BOSE amp plug, but, for the door subs, the wire is a thick gauge, so I don't think that there will be much effect.

ps: just realised I said "I'm not pretty convinced that the door subs are 2 ohm" - the "not" should have not been in that sentence and has now been amended - sorry. I believe that the door subs are 2 ohm given my testing, although it could be possible that the wire may have some resistance - unlikely, but I can't test that to prove it doesn't have a significant resistance.
 
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