Rodge, I take it that because of what you read from earlier posts that you've confirmed that your sub cable is attached to the correct sub output in the middle of the back panel of the 657. You probably also tried running the sub cable directly from one of the left or right analog outputs on your player, but this made no difference. The fact that some bass is getting through would seem to indicate that the sub cable itself was okay, but if you haven't already done so you might temporarily disconnect one of your other coaxial cables and try it with the sub. Yet another connection to try would be disconnecting the speaker wires from your M3 front speakers and temporarily connecting them to the speaker level inputs on the 350(with the 657 set to no sub so that all the bass goes out from the main speaker terminals)to see if the volume problem persists.
With the settings you described the volume should be high indeed, and lower settings(e.g. about midway on the 657 sub level setting)should suffice. If none of the foregoing has worked it would appear that the amplifier in the sub is defective and that Joe Vassallo at Axiom should be contacted. He may have further suggestions or send out a replacement amplifier, but from past experience you can be sure that Axiom will help to solve the problem.
