Acoustics; Test For Prominent Discrete Tones (Pdts) - Seagate Exos 512N Product Manual

2.6.4.2 Vibration
a. Linear Random Operating Vibration
The drive will operate without non-recoverable errors while being subjected to the random power spectral density noise
specified below.
b. Random Rotary Operating Vibration
The drive will exhibit greater than 90% throughput for sequential and random write operations while subjected to the shaped
random power spectral density noise specified below.
c. Linear Random Non-Operating Vibration
The drive will not incur physical damage or have non-recoverable errors after being subjected to the power spectral density noise
specified below.
2.7

Acoustics

Drive acoustics are measured as overall A-weighted acoustic sound power levels (no pure tones). All measurements 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.
For seek mode tests, the drive is placed in seek mode only. The number of seeks per
second is defined by the following equation:
Note
(Number of seeks per second = 0.4 / (average latency + average access time
)
Table 5 Fluid Dynamic Bearing (FDB) motor acoustics
All models
*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.
2.8

Test for Prominent Discrete Tones (PDTs)

Seagate follows the ECMA-74 standards for measurement and identification of PDTs. An exception to this process is the use of the
absolute threshold of hearing. Seagate uses this threshold curve (originated in ISO 389-7) to discern tone audibility and to compensate
for the inaudible components of sound prior to computation of tone ratios according to Annex D of the ECMA-74 standards.
Seagate Exos 7E8 SATA Product Manual, Rev. C
Idle*
2.8 bels (typ)
3.0 bels (max)
Performance seek
3.2 bels (typ)
3.4 bels (max)
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