Fewer Deaf Ears: HP's Noise Ratings for Office Servers

In a small office, there's no escaping a server's noise. In the previous noise-related posting we looked at entry-level servers from Fujitsu and Dell that should not drown out conversation, with decibels outputs of 32 and 38 decibels, respectively. This time we'll look at Hewlett-Packard servers.While getting at them takes considerable digging, HP does indeed publish decibel ratings for its low-end tower servers, and, better yet, their decibel ratings are more precise, giving both L-WAd and L-pAm figures.

The first (L-WAd) is the upper-limit A-weighted sound level, meaning it has been mathematically "weighted" to emphasize the 3-6 kilohertz range, where the human ear is most sensitive. It is usually measured in bels. The second (L-pAm) is the average A-weighted noise one meter away and is typically measured in decibels (one-tenth of a bel.) L-pAm can be excepted to be a little lower than L-WAd. (In the previous posting, the Dell figure was evidently equivalent to L-WAd, while the Fujitsu figure was not qualified.)

Using the L-pAm figure seems more appropriate in office settings. In that regard, the entry-level ProLiant ML110 Generation 5 had an L-pAm rating of 34 decibels while operating and 26 decibels while idlefor the SATA model. The SAS model was rated at 40 and 34 decibels, respectively. SAS drives spin at 16,000 rpm and the SATA drive spin at 7,500 rpm, and presumably that accounts for the difference.

The ProLiant ML115 Generation 5 was rated at 30 decibels while idling and 32.5 while operating. The ProLiant ML150 Generation 5 was rated at 36.5 decibels while idling and 36.9 while operating.

All the ratings are less than 40 decibels, indicating that they should be endurable in a small office.

In future noise-related posting we'll look at noise ratings from other vendors of office servers.

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