One of the most important responsibilities of an AV receiver is to decode surround sound formats in your audio and video programming. The DAC and the DSP are two chips that handle all this.
Short for Digital Audio Converter, this is a system that converts a digital signal into an analog signal.
In other words, DACs take the digitally encoded musical signals from a variety of sources, and converts them into analog ones that can be understood by the amplifier in your receiver and speakers. This makes them downright important for a great home theater experience.
What is a DAC?
There seems to be a bit of race going on between hardware makers these days, with each vendor coming out with models that have powerful new DACs that come with higher capacities. Which is great, because digital audio converters are very important to system performance, and are used in everything from televisions to mobile phones, tablets and computers, to home theater equipment.
To understand what separates a good DAC from a great one, you will have to find their ratings.
DACs are rated by the frequency of digital signal and the number of bits it can decode. As an example, many digital audio converters are rated for 96 kHz and 24 bits, which is the minimum you should choose for a receiver. More expensive models offer ratings of 192 kHz and 24 bits, and these are great for listening to hi-fi or high-resolution audio. The difference may only be noted by audiophiles, with premium hardware, but the difference is there, no matter how minor.
The importance of DACs
Once anonymous, DACs are now a heralded component of an entertainment system. They are the key to unlocking the convenience of digital music. Any device that deal with digital sound — be it a CD or Bluray player, game console or portable media player — makes use of a digital audio converter to convert its audio to an analog signal before output.
And that is because neither do amplifiers amplify in digital, nor do speakers play in digital, or our eyes see in digital. All these devices handle content in the analog waveform, even the digital one that is stored in the form of 0s and 1s on your hard disk or disc. Back in the days, analog recordings were the norm, and content stored on vinyl records and cassette tapes. The digital revolution was kickstarted with the arrival of the CD, and the world started storing digital audio in the form of Pulse Code Modulation, more commonly known as PCM.
Digital audio can be stored in a variety of sample rates, bit depths, encoding and compression format. But no matter how it comes, it is the job of the DAC to make sense of it all and translate it as accurately as possible from its binary format to as close as the original analog recording as possible.
So then, is a dedicated DAC worth it, when you already have a good AV receiver?
Most folks will not be able to tell the difference, blind testing with both the receiver and the DAC, even with excellent quality speakers and headphones. Ultimately, this will come down to how good the dedicated DAC is. With matched levels, it is very hard to distinguish between them. The only real advantage in moving to a dedicated box is when you invest a few thousands on your DACs, ICs and amps, in a separates setup.
In most cases, for most people, it is better to save money on a better AV receiver, or an expensive speaker system.