Seagate NAS HDD Product Manual, Rev. F
18
www.seagate.com
Drive Specifications
2.10 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.
*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
.
2.10.1 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.
2.11 Electromagnetic immunity
When properly installed in a representative host system, the drive operates without errors or degradation in performance
when subjected to the radio frequency (RF) environments defined in
Table 8
.
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 l average access time
Table 7
Fluid Dynamic Bearing (FDB) motor acoustics
Idle*
Seek
1TB models
1.9 bels (typ)
2.0 bels (max)
2.1 bels (typ)
2.2 bels (max)
2TB models
2.1 bels (typ)
2.3 bels (max)
2.3 bels (typ)
2.4 bels (max)
3TB & 4TB models
2.3 bels (typical)
2.4 bels (max)
2.5 bels (typical)
2.6 bels (max)
6TB & 8TB models
2.7 bels (typical)
2.8 bels (max)
2.8 bels (typical)
2.9 bels (max)
Table 8
Radio frequency environments
Test
Description
Performance
level
Reference
standard
Electrostatic discharge
Contact, HCP, VCP: ± 4 kV; Air: ± 8 kV
B
EN61000-4-2: 95
Radiated RF immunity
80MHz to 1,000MHz, 3 V/m,
80% AM with 1kHz sine
900MHz, 3 V/m, 50% pulse modulation @ 200Hz
A
EN61000-4-3: 96
ENV50204: 95
Electrical fast transient
± 1 kV on AC mains, ± 0.5 kV on external I/O
B
EN61000-4-4: 95
Surge immunity
± 1 kV differential, ± 2 kV common,
AC mains
B
EN61000-4-5: 95
Conducted RF immunity
150kHz to 80MHz, 3 Vrms, 80% AM with 1kHz sine
A
EN61000-4-6: 97
Voltage dips, interrupts
0% open, 5 seconds
0% short, 5 seconds
40%, 0.10 seconds
70%, 0.01 seconds
C
C
C
B
EN61000-4-11: 94
