Hi there,the problem lies in the difference between impeadance and resistance.When you're playing through your amp,AC voltage is flowing to the spkr.,when you measure the spkr.with your meter,(analogue or digital),DC voltage is flowing through it because of the battery in your meter.The reading from the meter will always be less than the imp.value stamped on the spkr.An 8 0hm spkr.(imp.) will read around 5.6 ohms(res.),a 16 ohm will read around 11.6.Hope this isn't too confusing,Mel.