Bose SIE2i Review
Go for gold with a little help from Bose.
Under the Hood
I tested a solid, balanced frequency response from the Bose SIE2i (MSRP $149.95), optimal levels of harmonic distortion, average channel tracking, and good overall impulse response. This product's only drawbacks stem from its design: Poor isolation and a somewhat high degree of leakage both owe to the earbud form factor.
We test a speaker's frequency response from 20Hz to 20kHz to determine how much credence it lends to each audible pitch. These Bose perform well in this category—their frequency response somewhat resembles an equal-loudness contour (ELC), which equalizes the volume of all frequencies for the human ear.
Expect an ample foundation of sub-bass and bass notes, and a midrange that holds its own. There is a slight drop in volume between 2kHz and 4kHz, so that details throughout the high mids may be harder to distinguish at times. Largely, though, there are no drastic issues here—this is a fine test result.
Tracking refers to the balance between sound output for the right and left channels, or speakers. Headphones with poor tracking can have audible discrepancies in channel volume for particular frequencies, which can be both distracting and bad for your hearing. Fortunately, the SIE2i tested with no major tracking errors—no sudden shifts in emphasis over 2 dB in volume, which is practically perfect.
Attenuation is one area where the SIE2i are not the best of performers—and for obvious reasons. Attenuation refers to a set of headphones' ability to block, reduce, or dampen outside ambient noise. Obviously, a pair of active noise cancelers is going to do a much better job than these buds, which sit in the ear and block almost nothing of the sub-bass, bass, and midrange frequencies. They do, however, reduce some high midrange sounds to as much as one-quarter of their original volume.
THD (or Total Harmonic Distortion) refers to the sum of electrical/mechanical audio interference a loudspeaker exhibits during playback. Typically, we like to see less than 3% total distortion, and fortunately the SIE2i tested within that acceptable range.
Users should note, however, that the maximum volume for distortion free playback is a little lower than usual for these ear buds—about 98 dB—but you shouldn't be listening to music louder than 100 dB for extended periods, anyway.
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