Out of curiosity, what does your Init-String look like?
Something along these lines?
AT&F&C1&D2E0S0=0M1
Because according to the information given to me:
M0 or M Speaker off, completely silent during dialing M3 is also common, but different on many brands
M1 Speaker on until remote carrier detected (i.e. until the other modem is heard)
M2 Speaker always on (data sounds are heard after CONNECT)
Removing the M1 at the end fixed it for me.