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Intermittent powered speaker, woofer impedance at 1.7ohms!

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Yamin:
Hi guys,
I've got a mackie thump15 powered speaker in for repairs. The issue was the sound cuts out when the speaker is turned up loud. My initial thought was dry joints and intermittent connection due to vibration.
When I got it in and after removing the amp I measured the resistance of the drivers and the woofer measures at 1.7ohm!. That didn't look right. The marking on the speaker states that its suppose to be 8 ohms. So then my thought was the speaker coil have shorted partly and the amplifier chip was detecting a fault when driven hard and was cutting out. The amplifier chip used is TDA8924TH.
But here is where things got a bit interesting. To check whether the amplifier was functioning I connected my test woofer rated at 8 ohms and it was working fine no issues (my test woofer was not attached to the enclosure). To see whether the sound cuts out, I then checked with the faulty woofer and it worked perfectly fine :S and same as before the woofer is not attached to the enclosure.
 I haven't got a working mackie thump to measure the actual resistance of the coil of the woofer. The label on the speaker says 8 ohms though I know sometimes labels can be misleading. If some one can confirm the resistance of these would be greatly appreciated. Can the TDA8924TH be paired with a 2 Ohm-ish load and work?
Thanks in advance for your input.

TimFox:
Eight ohms should be the AC impedance (not constant over frequency) that results from the coupling of the speaker and the air.  The DC resistance should be less: otherwise, the system is very inefficient.
You could measure the speaker impedance (including acoustic load) by placing 1 to 4 ohms in series with the ground lead to measure the current when driving the disconnected speaker from an audio signal generator (maybe 50 or 600 ohms source impedance) and measuring the AC voltages across the coil and across the resistor with an oscilloscope or AC voltmeter.  Make sure the voltmeter is good at your frequency range:  they all have a high frequency limit, and for a subwoofer the AC response may fall off at low frequency.  With an oscilloscope, you may have problems with a common ground, and measure the total voltage (coil plus resistor) and do some complex (phase sensitive) math.

Yamin:
Thanks @TimFox, normally with an 8 ohm rated speaker I do get around 6-7ohm DC resistance. If I'm measuring around 1.7 ohm DC resistance could it still be considered ok?

TimFox:
I don’t have specific examples, but I would suspect that a subwoofer would have lower resistance (compared with nominal impedance) than mid-range or tweeters.  Also, speaker systems with crossover networks have extra resistance in the networks.  Efficiency is probably more important for subwoofers.  Many multi-speaker systems have passive variable attenuators for the high-frequency units.  The AC impedance is a “good thing”, since it couples your amplifier’s output power to acoustic power, but the DC resistance is only an inefficiency. 

After writing that, I looked at some Jensen guitar speakers, around 12 to 15 inch, and found that the 8 ohm units did have spec values of around 5 ohms for DC.

Audiorepair:
An 8 0hm speaker measuring 1.7 ohms resistance is f**ked.

Your normal measurements of 6-7 ohms is what you should expect.

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