Interestingly, Apple elected to go with the Realtek ALC885 audio codec for the audio. This is Realtek’s flagship CODEC with a SNR rated at 106 dB. The Dell XPS M1330 and Inspiron 1525 use the IDT STAC9228 with a SNR rated at 105 dB. The HP 2133 Mini Note and Lenovo X300 use a conventional AD1984 with just 96 dB of SNR. A vintage Dell Inspiron 700m used a STAC9750 rated at 90 dB SNR.
The actual analog audio quality from a notebook is affected by the electrical milieu that the audio chip is installed in, and therefore, the specifications of each chip are not entirely predictive of audio quality. My iPod and iPhone offer superior sound to the MacBook despite having a DAC with less theoretical SNR. Still, the MacBook has very good analog audio for a notebook especially when compared to other notebooks. Using the standard iPhone headphone, the MacBook offered very good performance just barely audible background hiss. The baseline hiss became more prominent with in-ear monitors such as our Apple In-Ear Headphones and even more prominent with our Ultimate Ears Super.Fi 3’s. However, the background hiss did not change with the volume setting, CPU utilization, or HDD access as is the case with other laptops. We found that the noise blended into the background when listening to music. However, when the music stopped, it was noticeable. Perhaps more important is that Apple appears to be consciously designing their laptops for a premium multimedia experience--they easily could have gone with the lower-priced, but similarly featured Realtek ALC888 (used in Dell Studio Hybrid desktops) with just 98 dB rated SNR, but instead chose to implement the higher-performing ALC885.
Speaking of the new Apple In-Ear Headphones, in line with Apple’s philosophy of product integration, the MacBook’s audio port is 100% compatible with the latest iPod and iPhone accessories. The iPhone headphone/mic works perfectly with the MacBook, including the button: one click to play/pause, two clicks to skip to the next track, and three clicks to skip to the previous track. Even cooler, the new In-Ear Headphones with the dual drivers works too. Not only do the single, double, and triple click shortcuts work, the volume control buttons work too. One of the nice things about the MacBook is that it keeps track of separate volume settings for the headphone jack and the integrated speakers.