It is possible to view or modify the acoustic settings of an IDE/Serial ATA hard disk if this feature is supported by the disk. Higher acoustic levels will enable faster (but louder) operation. Setting a lower level will make the disk slower and more silent (the read/write head positioning will be slower and more silent). The acoustic setting has no effect on the drive rotation speed.
If supported by the disk, it is possible to modify the acoustic level in this window. By using the slider, the user can choose which is important for him (silent or fast operation or he can select a balance between the endpoints). The recommended acoustic level (determined by the manufacturer) is displayed. Setting any acoustic level will not affect the health of the hard disk.
If two or more hard disks are tested and compared (for example, in a benchmark) all disks should have the same acoustic level configured (eg. fastest or slowest) to get accurate results.
Note: the acoustic level configuration highly depends on the capabilities of the host (controller, motherboad) and the installed drivers. If the controller or the driver does not support this feature, an error message is displayed and the acoustic level remains unchanged. Using different controller or changing disk controller driver may help in this case. Some hard disks only offer two values on the two ends of the slider (so setting a middle level may switch to the end) while other disk drives may allow adjusting to balanced setting.
Generally hard disks should preserve (keep) the setting configured across power cycles, so after power OFF/ON cycle, the configured value should be used. However, most hard disks reset the value on power cycle. Hard Disk Sentinel has an option called Automatically adjust the setting on restart option when you configure / adjust APM setting: so then Hard Disk Sentinel automatically re-adjusts when required (for example on next startup if the device seems forgot the value adjusted).
The same configuration and settings (and note about the Automatically adjust the setting on restart option) is applicable for other disk features, like the Advanced Power Management setting and Free-fall control too.
By adjusting the Advanced Power Management setting, we can control if the drive should preserve power (and park/spin down in all possible situations) or to keep spinning and prevent parking even in idle situations. Many drives park heads very frequently by default (which may reduce disk lifetime for a minimal power save) so it may be better to configure the rightmost value (FEh - highest power consumption) with Hard Disk Sentinel to prevent parking/spin down and increase disk lifetime (if supported by the drive and applicable, for example disk drives used in desktop systems). Note that this setting is completely independent from the Windows power management (hard disk spin down timeout) setting.
By adjusting the Free-fall control sensitivity (if supported by the disk drive) we can tune how quickly the drive should move the heads away from the surface to the parking area when it detects acceleration (usually falling disk/system) to avoid disk failure. Some notebook hard disks support this function and allows adjusting the sensitivity - usually they provide an attribute "Free-fall event count" on the S.M.A.R.T. attribute list too, to count how many times the drive experienced such events.