Just to chime in to express my disappointment with the Zx model's ACM.
THE ACM DEGRADES THE SOUND QUALITY!
I tested the sound coming out of the ACM versus plugging my headphones directly into the sound card and the difference is major. I actually used the sound card without the ACM for a week or so. As soon as I decided to use the ACM, I could immediately hear that it was worse...especially while using the surround sound feature. It sound weaker and tinny. With out the ACM things are much clearer and precise. I had to play with the volume higher using the ACM as it seems to weaken the amps power.
Testing it while playing Black Ops 2...it was like night and day. Without the AMC my gun shoots sound loud, fast and punchy. Playing through the AMC the gun shoots are very much recessed and weak.
I actually thought my ACM was defective and Amazon sent me a replacement...just to be disappointed that the same issue existed with the new AMC. I placed the replacement sound card in as well and even reinstalled all software and drivers......SAME ISSUE.
I highly recommend the sound card itself (if you are plugging directly in to the sound card) but stick with the cheaper Z model that does not include the ACM.
Here is a link to my amazon review:
If you own the ACM and can test this for yourself, please let me know if you have the same issue.
It may be that I happened to get 2 defective AMCs in a row....and in that case....I would still stay away from the Zx models and save the $50 with the Z.