Speaker impedance question

[Danelectron]

I recently purchased two telefunken 8" speakers similar to the link below. They were advertised as 4 ohm but actually measure approx. 1.25 ohms. I realize the actual measurement is usually lower than 4, 8, 16 etc. but 1.25 from a 4 ohm? I hooked one up to a 4 ohm output on a 5F2-A build and it sounded O.K. I haven't built a cabinet for these yet so I just plugged it in sitting on top of the amp. No real dynamics, but I wanted to see if there was any real issues before remounting into something.

I have a couple of questions.

How critical is impedance? Is there a range that can be adequate without being on a gnats a**?

I was going to use these two in series (going by advertised rating) and paralleled with a Jensen or celestion 8 ohm to get a total of 4 ohms or these 3 in series (16 ohms) and parallel them with a celestion 16 ohm I have for a total of 8 ohms. I also considered that as low as the impedance is on these, can I just series them with an 8 ohm on an 8 ohm output ?

Does it make a difference if the speakers have different wattage ratings as long as I don't overpower the lowest rated speaker?

Are there any other issues I may have with any of these scenarios?

Thanks to all in advance for any help. I look forward to the day I can help in return.









Telefunken Fullrange AlNico Phenolic Spider Speaker - eBay (item 390142981821 end time Jan-20-10 09:55:58 PST)

[Danelectron]

I found my answer. Can anyone tell me how to remove this post?

[oc disorder]

send a message to Tboy but we wont hold it against you...
faulty meter?

[Danelectron]

No, I read somewhere about the fact that the DC resistance will be lower than actual impedance. I still think 1.25 is too low, but they sound O.K. Maybe they're 2 ohm speakers. I have three meters. I tried two of them with the same result. Should I go out to my van and get the third one?
I'm going to go ahead with a plan and check final resistance and output accordingly.
Thanks for the info. Is Tboy the supreme creator of this forum?

[Bruce / Mission Amps]

No, I read somewhere about the fact that the DC resistance will be lower than actual impedance. I still think 1.25 is too low, but they sound O.K. Maybe they're 2 ohm speakers. I have three meters. I tried two of them with the same result. Should I go out to my van and get the third one?
I'm going to go ahead with a plan and check final resistance and output accordingly.
Thanks for the info. Is Tboy the supreme creator of this forum?

Well, for what its worth, I've never had a 4 ohm speaker measure less then just under 3, DCR ohms. Other then some crazy trunk mounted boom boom maker bottom, I can't remember ever having to deal with a 2 ohm speaker.
But, what if it was a 4 ohm speaker with thick voice coil wire so it could handle high current? The DC resistance could be very low and the actual impedance could still be around 3-4 ohms.

[Danelectron]

Bruce,
Could very well be. These are supposed to be high quality speakers. The magnets are supposed to be superior. Is there a way to test ACTUAL impedance? I want to research more about coils and transformers to get a clearer understanding of their characteristics. Chokes in lew of resistors in power supplies are still a mystery to me.
If I treat them as 4 ohm and use one in series with a 16 ohm paralleled with another like setup I will have possibly 10 ohms and if the actual value is 2 ohms I will end up with 9 ohms if that makes sense. Either way shouldn't be too hard on the output transformer set up for 8 ohms.
I figure if I set them up this way it wouldn't be as drastic a difference as if I set up just the two in series (8 or 4 ohms).

Thanks for your input!