Palm OS Handheld Computers: Alarm Loudness Comparison Test

Objectives

1) To measure and compare the alarm loudness of various PalmOS handheld computers.
2) To measure and compare the loudness of the different stock alarm sounds on two representative PalmOS handheld computers.

Methods and Materials

A total of fifteen PalmOS devices were prepared with fresh batteries / full charges, and any cases or covers were removed. The Alarm Sound setting on each device was set to "High" in the Preferences > General screen. The handheld devices were placed on a flat surface (an X-acto cutting board) 20 cm from the decibel meter's sensor, and the standard alarm sound ("Alarm") was triggered. This was conducted for each handheld until a repeatable average reading was obtained (typically 3 to 6 times).

For the second test, the Palm V and Palm m100 were used as per the first test, but each of the seven standard alarm sounds were measured (using the built-in DateBook application: Menu > Preferences > Alarm Sound).

The measurement device was a Radio Shack Sound Level Meter (model 33-2050) with an analog display measuring in decibels (dB). Weighting was set to "A" (500 to 10,000 Hz - the frequency range of greatest sensitivity to the human ear). Response was set to "Slow" to obtain average sound levels (the instrument does not include a peak averaging feature).
(note: accuracy and calibration specifications were not available for this instrument.)

Results and Discussion

Test 1: Average Peak Loudness of Different PalmOS Devices:

[models in square brackets are untested devices assumed to be equivalent]

It is apparent from the above data that the majority of PalmOS devices tested have very similar average alarm volumes of 72 dB (+/- 2 dB). The original pilot and Palm III devices produced alarms that were somewhat quieter than average. The Palm Pilot Pro device tested was louder than average. The TRGpro and HandEra 330 use true speakers (as opposed to the piezo-electric "beepers" in all the other devices), and produced alarm volumes significantly louder than average.

Test 2: Average Peak Loudness of Standard PalmOS Alarm Sounds (Palm V and Palm m100)

The results from this test show that the "Alert" and "Bird" sounds are quieter than the other sounds on both devices. For the Palm V, the other five sounds have approximately the same volume. However, while the Palm m100 has similar volumes for the "Alarm", "Phone" and "Sci-fi" sounds, the "Concerto" sound is approximately 10dB louder, and the "Wake up" sound is approximately 16 dB louder. This may be due to frequency response characteristics of the piezo speaker used in the m100 and / or modification of the sound files for these two particular sounds. Regardless of the cause, these two alarm sounds are noticeably louder.

Conclusions

With the standard PalmOS Alarm sound, most of the tested devices produce very similar loudness. The TRGpro and HandEra 330, which use true speakers instead of piezo-electric speakers, produced significantly louder alarms.

The different alarm sounds found in devices running PalmOS 3 and higher have different volume levels, but the relative loudness is not consistent between devices. In particular, the Palm m100 "Wake up" sound was significantly louder than the standard "Alarm" sound.

A number of Palm OS devices were not available for testing: Symbol SPT-1700; Qualcomm pdQ; Visor Platinum; Visor Edge; Sony PEG-N700C; Kyocera QCP-6035, Samsung SPH-I300. This test may be updated in the future as access to these devices is obtained.

Please note: although every effort was made to reduce any bias in the testing, the accuracy of the measurement device and the specific setup used in the test environment may have affected the results somewhat. Minor differences among many of the devices should not be over-emphasized. (i.e. a couple of decibels is not very noticeable, and is likely within the assumed margin of error for this test. Furthermore, if a test distance of, say, 30 cm, was used instead of 20 cm, relative loudness of various devices might have been affected.) YMMV :-)

Thanks to Graemme Brown of Zen Mastering for the loan of the dB Meter.