Motorola Krzr K1m Review - Audio Quality
|
Alfredo Padilla Published on April 20, 2007 Comment on this |
|
|
|
|
To test the audio performance of phones like the Krazr, we use the same equipment that audio professionals use; a HATS (Head And Torso Simulator) combined with a professional audio analysis package called Soundcheck. The HATS simulates a human head and torso, including how sound reflects from the head and shoulders. Highly calibrated microphones inside the ears capture the sound in the same way that the human ear does, and a speaker in the mouth simulates the human voice. This device is controlled by the Soundcheck software (produced by Listen Inc), which analyzes the sound the HATS captures to tell us how good it sounds. For more on how we test, see here
Overall, the Krazr K1m had very good sound quality; we found that most of the frequency response curves were within the limits that we expect, and that the phone produced clear, easy to understand speech. However, there were a few unexpected aspects to the sound that detract slightly from the sound quality.
Sound Receive Frequency Response (7.71)
This test measures the frequency response of the phone for the sound it receives (such as someone talking to you over the phone). Our test system sends the phone sounds at known frequencies and measures how well these sounds are reproduced (indicated by the blue line). We measure this against the limits set in a standard defined by a group of international audio experts (as shown by the red lines). The frequency response of an ideal phone should run right between these two limits. The Krzr K1m did pretty well on this test; the frequency response is within the limits. However, it is not particularly smooth: there is a significant dip in the response in the middle of the range, and then a jump at the higher frequencies. This could lead to higher frequencies being overly exaggerated at the cost of the mid-range ones, which may make some voices harder to understand.
Sound Send Frequency Response (7.36)
In this test, we measure the frequency response of the phone when sending audio. This measures how well the phone detects and transmits sounds at different frequencies (as shown by the blue line, with lower frequencies at the left and higher at the right). We measure this against the limits set by audio experts for digital phones (shown by the red lines); an ideal phone should have a frequency response that passes right between the two red lines. The Krazr K1m did well on this test; the frequency response curve is smooth, which means that no frequencies are suppressed or exaggerated. However, the line oes get a little close to the limits at the lower frequencies; the standard we measure against calls for phones to have a slightly slower response to low-frequency sounds as they are not as important to making speech comprehensible. But this is a relatively minor issue, and the K1m had impressive performance overall for the sound it sent.
Handset Side Tone (6.9)
Side tone is how cell phones let you hear your own voice; they inject a small amount of your captured voice back into the speaker, so you can hear yourself speak and judge how loud your own voice is. How much of this captured sound they pass back is critical; the standard calls for -18db, but we measured the K1m as being a little lower, at -21.1dB.This isn’t a serious problem, but it does indicate that the K1m injects a little less of your own voice back into the speaker, so you might find yourself talking a bit louder than you really need to.
| Previous Next | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
