Although substantially true, this is not absolutely true, since my old laptop could write audio to sd through its inbuilt slot since made by Toshiba, a co-inventor of the SD format. They obviously had all of the relevant sd code in their firmware, something that all hardware does not necessarily have (those that do not pay the royalties). Also my Panasonic PCMCIA SD reader could write audio (another defunct format). Whether any models today can do this I can't say without having tried every one. The limitation was a result of the "secure" part of the format. It was designed to preserve copyright on retail downloaded music to prevent copying, but this part of the technology never took off commercially. Remember at the time SD was still a new format vying to usurp Compact Flash from top spot, let alone things like MMC and XD which have since disappeared into history, like Technics.