We rip CDs for customers. With the Acronova Nimbie robot.
Today a customer reports that our results are terrible. He says our FLAC sounds as bad as MP3.
He would be very disappointed with the sound quality.
He uses a Mac with the XLD software and would have significantly better results.
He says the difference is immediately audible when he rips a CD for test purposes.

At the moment, the customer still owes us proof of the quality of its ribbed versions.
Therefore we ask here in advance.

Could it be because of the FLAC converter?
We use the secure option and all results are accurate.
We are currently using dbPowerAmp version 16.5.

Is there anything known or could anything be improved?
Or does someone have an idea what could be wrong?
Please help.