Product manual

16
DB35.3 Series PATA Product Manual, Rev. B
2.10 Acoustics
Drive acoustics are measured as overall A-weighted acoustic sound power levels (no pure tones). All mea-
surements are consistent with ISO document 7779. Sound power measurements are taken under essentially
free-field conditions over a reflecting plane. For all tests, the drive is oriented with the cover facing upward.
Note. For seek mode tests, the drive is placed in seek mode only. The number of seeks per second is defined
by the following equation:
(Number of seeks per second = 0.4 / (average latency + average access time)
*During periods of drive idle, some offline activity may occur according to the S.M.A.R.T. specification, which may increase acoustic and
power to operational levels.
Table 4: Fluid Dynamic Bearing (FDB) motor acoustics
Idle* CE seek profile
ST3750840ACE 2.8 bels (typ)
3.0 bels (max)
2.9 bels (typ)
3.0 bels (max)
ST3500830ACE 2.8 bels (typ)
3.0 bels (max)
2.9 bels (typ)
3.0 bels (max)
ST3400820ACE 2.7 bels (typ)
2.9 bels (max)
2.8 bels (typ)
2.9 bels (max)
ST3320820ACE 2.7 bels (typ)
2.9 bels (max)
2.8 bels (typ)
2.9 bels (max)
ST3300820ACE 2.5 bels (typ)
2.7 bels (max)
2.7 bels (typ)
2.8 bels (max)
ST3250820ACE 2.5 bels (typ)
2.7 bels (max)
2.7 bels (typ)
2.8 bels (max)