Amazon on Tuesday announced a new streaming music tier that offers more than 50 million tracks in 'High Definition' and millions of additional songs in 'Ultra High Definition,' the highest quality streaming audio it offers. Amazon describes High Definition as music with a bit depth of 16 bits and a sample rate of 44.1kHz, or CD quality, while Ultra HD is said to have a bit depth of 24 bits and a sample rate up to 192kHz. The company says its streaming service will automatically play the highest quality audio supported by the user's device and network conditions. The new service, dubbed Amazon Music HD, is now available to listeners in the US, the UK, Germany and Japan. It's available to try free for 90 days for both newcomers and existing Amazon Music subscribers. After that, you'll pay $14.99 per month (or $12.99 per month for Prime members) or an additional $5 on top of your current individual or Family Plan subscription. That's a bit more affordable than Tidal which many consider to be the leader in lossless streaming. Tidal offers a base plan at $9.99 per month but if you want its highest-quality option, it'll set you back $19.99 per month.