DD1, where to put the negative lead probe, amp ground or negative speaker connection?

[JohnPD]

I've read in here and elsewhere to put the positive to the positive speaker wire connection on the amp, which is obvious, but what about the negative? Attach it to the amp ground, or the negative speaker wire connection on the amp? My instruction manual says the negative speaker wire connection, but I've read in here to use the amps ground wire connection.

[audiofanaticz]

Usually the negative speaker wire output is fine to use, however on some amps if it don't work then the negative battery terminal will work as well. Most amps the negative speaker terminal and the negative battery terminal are tied together, but thats not always the case and thats really the only time you need to use the negative terminal or vice versa.