ChanSpy() Sound Quality

I’m using Asterisk with ztdummy and am having the following issue:

When I use ChanSpy(SIP), the sound quality from the original caller is terrible while the quality from the original call receiver is fine. That is, the channel being listened to provides good quality sound from one party but not from the other.

Thanks in advance.

what version of asterisk are you using? upgrading it may improve the quality. search for chanspy on this forum.