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Fraunhofer L3ENC 2.71 MPEG 1 Layer III Encoder

Diamond RIO Portable Player

Discussion of Results

Performance of this very small, portable playback-only device is suitable for casual use, where slightly audible high frequency losses and moderate, but usually inaudible distortion just below peak output is tolerable. Listening tests were with done using Sony 7506 professional headphones. which this machine does not drive very hard. There are no useful gain reserves for playing program material that was perhaps mistakenly recorded at somewhat lower than peak level or has extreme dynamic range.

Clipping into a high impedance load commences at about 1 dB below full output (FS output = 0.90 volts) at 1 KHz. At full output, 1 KHz THD is about 3.5%. Maximum undistorted output at 20 Hz is about 4 dB below peak output at 1 KHz.

SNR measurements are dominated by distortion, which the analysis program erroniously included in the noise calculations. Therefore, SNR is rated better than the numerical result suggests. Dynamic range and zero-signal measurements suggest that audible noise is unlikely to be a problem in typical use. Overall sound quality seemed slightly poorer than a portable CD or MD player, but better than cassette tape.

Available playback functions are similar to that of a good, simple CD player including the ability to repeat a track, all tracks, and an arbitrary selection. Player ergonomics seem good, and its major functions seemed easy to memorize and use only by touch.

Unlike many portable CD players, operating Rio in a high-shock environment does not require the use of additional electronic features that further degrade sound quality. It seems like the only way that shock would affect this unit's operation would be through actual mechanical damage or by knocking the battery out of the case. Other than the pushbuttons, there are no moving parts. The download cable seems to be reasonably durable for use by a careful, dexterous person.

Rio's LCD display seems somewhat exposed to possible damage. It is unlit, but gives relevant status information as the player was put though its paces. The LCD indication of download operations was small and not intuitive. However, concurrent indications on the computer managing the download are unmistakable, once you see it happen the first time.

Rio's Win95/98 download and management software is supplied on a CD, and seems simple, rapid, and convenient to use. It loads no device drivers and does not require rebooting after installation. The hardware printer port adaptor did not slow or interfere with non-concurrent operation of an inkjet printer that shared the printer port. The download and management software allowed rapid playlist reorganization, including the ability to add MP3 files using drag-and-drop mouse operations. The inability to print up the names of the files loaded of the player seems a curious omission, given that only file numbers can be viewed using the player's display.

Downloading 3 megabytes of music (about 3 minutes of program material recorded at 128 Kbps) takes about 30 seconds, as claimed. A USB interface seems desirable, but is not available at this time. A memory expansion card fits inside the unit, but was not obtained or tested. With 128 Kbps MP3 encoding, RIO stores about a half hour of music with the standard memory.

All tests shown here were done with a fresh alkaline battery. Performance remained pretty consistent up until a few minutes before the point where the device shut down due to a discharged battery. The battery status indicator seemed to give reasonable reports as an alkaline battery was used up. Battery life is around 10 hours for continuous play into a high impedance load. It was possible to discharge and replace the single 1.5 volt AA battery, without losing any program material.

At the time this report was written (March, 1999), Rio is a unique, highly compact, and potentially durable variation on the portable music player theme that has been under development for about a decade. Its dependence on a Windows computer for downloading music is a minor limitation for most prospective users, at this time.

L3ENC 2.71 encoder, Diamond RIO Portable Player Frequency Response

L3ENC 2.71 encoder, Diamond RIO Portable Player Frequency response

L3ENC 2.71 encoder, Diamong RIO Portable Player Frequency Response, one channel 20 dB down

L3ENC 2.71 encoder, Diamond RIO Portable Player Frequency response, one channel 20 dB down

L3ENC 2.71 encoder, Diamond RIO Portable Player 1 KHz Total Harmonic Distortion and Noise

L3ENC 2.71 encoder, WinAmp 2.09 decoder 1 KHz Total Harmonic Distortion and Noise

L3ENC 2.71 encoder, Diamond RIO Portable Player 20 Hz Total Harmonic Distortion and Noise

L3ENC 2.71 encoder, Diamond RIO Portable Player 20 Hz Total Harmonic Distortion and Noise

L3ENC 2.71 encoder, Diamond RIO Portable Player Noise output with zero input

L3ENC 2.71 encoder, Diamond RIO Portable Player Noise output with zero input

L3ENC 2.71 encoder, Diamond RIO Portable Player Residual Noise - (Dynamic Range)

L3ENC 2.71 encoder, Diamond RIO Portable Player Residual Noise - (Dynamic Range)

L3ENC 2.71 encoder, Diamond RIO Portable Player IM Distortion

L3ENC 2.71 encoder, Diamond RIO Portable Player IM Distortion; L3ENC 2.71 encoder, Diamond RIO Portable Player Analog AM & FM Distortion - "Jitter" L3ENC 2.71 encoder, Diamond RIO Portable Player AM & FM Distortion - "Jitter"