Should I Use an HDMI Audio Converter With my Apple TV?

Got a tech question for Sound & Vision? Email us at

Q I’m currently using an Apple TV 4K box that’s connected to my HDTV with an HDMI cable. For sound, I run a cable from the HDTV’s optical digital output to an external DAC connected to my stereo system. Here’s my question: Would it be a useful upgrade to buy an HDMI audio converter so I could connect to my stereo system directly without first routing the signal through the TV? —Kristóf Kollár

A Not necessarily. The HDMI interface is notoriously prone to jitter artifacts, so there are benefits to bypassing it, especially for music playback. Your Apple TV box only provides an HDMI output, however, so there’s no way to avoid using HDMI to transmit audio. It doesn’t matter if your TV serves as the digital audio extractor by passing a stereo signal through its optical digital output, or that same task is carried out by an HDMI audio converter , in both cases the sound quality is likely to be the same.

There is one instance where an HDMI audio converter could be a benefit: if you were to use it to feed a 5.1-channel signal to an AV receiver or surround sound preamplifier. Some HDTVs downconvert multichannel soundtracks to stereo by default when outputting them over a optical digital connection. With an HDMI audio converter in the mix, you could circumvent that limitation by routing the 5.1 audio signal directly from your Apple TV box to an optical digital input on a receiver or pre/pro.

mround's picture

Many if not most AV receivers can accept HDMI and pass the video through while extracting the audio. That's one of their primary functions after all. If you're doing 4K, of course, you need a receiver that's capable of passing that signal through.

An issue I've had with several TVs, using the optical output to the receiver (which you'll have to keep, anyway, to run TV sound from OTA), is loss of lip sync. Whether it's the TV doing it or the DAC in the receiver, I don't know, and it seems to vary by TV and DAC (when I used an external DAC it was worse), but there's a noticeable delay when playing through the receiver. If the TV speakers are left on, there's a really bad echo effect. Interestingly, in the old days (before DTV), the analog audio outs from the TV to the receiver did not produce this effect - but analog out is disabled with digital program material in most TVs now.