Ty419

I'm really sorry and I know this has been beat to death around here, but there are tons of conflicting claims in all the threads. I've been through dozens of replacement threads here and there are claims ranging from 2 ohms to 16 ohms and much in between.

For anyone that has been around long enough to see all these threads or for anyone that has replaced their sub and has it sitting around, do you recall a pic anywhere of a meter actually hooked up to the sub or could someone do that?

It seems like everyone guesses and then never updates the thread after replacement. Most of the threads with pics show how to replace it, but still fail to actually measure the speaker when it is out.

I ordered a JL 8 ohm sub to replace it, since most threads claim 12-16 ohms and that is as close as I can get. If nobody knows for sure, I'll measure mine when I take it out and update all the threads since mine isn't blown, just has separated surround so it should still show the correct impedance. Hopefully, I'll have the JL tomorrow and can work on it tomorrow night. If it is actually 2-4 ohms, I can use the Pioneer slim sub which only comes in 4 ohm impedance.

Jabberwock

As it turns out, actual speaker impedance is not a constant. The impedance of a speaker will vary with frequency. Manufacturers measure impedance over the speaker's entire audio (frequecy) range and then publish an "average". So a test with a multimeter across the speakers terminals at no load will not get you a usable result.


The sub in an LS430 is reputed to be rated at 16 ohms and I don't see any replacement 16 ohm rated speakers available currently other than the orginal ML subs. If it were my car I would likely replace the ML with a good quality 8ohm woofer. But first I'd first check with a high end driver supplier like Partsexpress.com, or madisound.com to see what they would recommend - both have extremely knowledgeable and helpful folks working in customer service. I am not shilling for these guys - have no connection - just have used them in the past to build customer speakers with good result.

mkorsu

True, but it's not an average. It's sometimes called nominal impedance or more correctly, Re (DC resistance of the voice coil at rest). It tends to be lower than the stated resistance though.

But you are 100% correct in that the impedance continuously changes as the cone vibrates. For "standards" sake, the DC resistance is used as a descriptor for the drivers and as a guideline for impedance loads for amplifiers to make it easier to match speaker configuration with the amplifier's accepted load value.

Not trying to come at you just trying to further the explanation!

mkorsu

Ty419. Your biggest problem may be that the factory amp may not like the 8 ohm load as opposed to the 16 ohm load. Be careful if you do go 8 ohms. I would suggest searching more to see if anyone has run an 8 ohm sub on the factory amp with success. I will search as well and let you know if I find anything.

mkorsu

After some searching, I would seriously consider using a quality sub with an aftermarket amp. Or, if trying to retain the factory appearance, get a new ML sub. I don't see anything that will work very well without risking the factory amp.

Jabberwock

No problem at all - More clarity is always a good thing. Speaker impedance is an black hole in most people's understanding of audio related electronics. I was just trying to make a point that a multimeter test across the terminals of a speaker is not going to provide much information in terms of making an assessment of a speaker's usefulness/fitness for a specific amp.