Is this normal?
 

I just a reading of 6.1 ohms on a dayton rs 150s-8. I thought that is was a 8 ohm speaker. I also took it out of the garage, could the cold have given me this off reading?

I'd have thought that your reading was perfectly normal. The figures quoted for speaker impedance are usually specified as "nominal". The measurement is made of a coil inside a magnetic field and the impedance will vary with fequency. An "8ohm" speaker is usually only exactly 8ohms at a 3 or 5 points depending on the frequency and the type of box it is in etc. . What you probably measured was the DC component which you would expect to be about 6ohms. I think its perfect. You might find a text book or website that discusses speaker impedance. You will find that will address your concerns with a better technical explanation.

Thats about right for an 8 ohm speaker. AC impedence is higher than the DC resistance.

mike