Hearing and Speech

[Sunrunners_Fire]

I've a bit of confusion that I'd love y'all's input on, in addition to an advantage I want to build. Hence:

[Confusion]

Subsonic Hearing (Basic Set, pg 89) allows the character to hear sound frequencies under 40 Hz. Erm. Human audible range goes down to 20 Hz. Anyone know why Basic Set assigned 40 Hz as the cutoff point?

Hyperspectral Vision [25] combines Infravision [10] and Ultravision [10] into a single trait while increasing the vision bonus to +3 from +2. I'd count that as Acute Hearing 1 [2]. I'm missing [3]. What bit am I missing to account for those points?

[Advantage]

I want to build Hyperfrequency Hearing. It'd combine Subsonic Hearing [5] and Ultrahearing [5]. Neither offer any hearing bonuses on their own, so I'm torn on offering a bonus for the combined capability. Hyperspectral Vision offers precedent for a bonus, but the advantages that it combines contain innate bonuses already ... but it has bits I'm not catching.

If I don't offer any bonuses, then Hyperfrequency Hearing should cost [10] as the total of its' components ... but Hyperspectral Vision doesn't cost [22] which is the total of its' components, it costs [25].

And, so, thereby ... whatcha got?

[Edit]

And because I forgot the speech part (!), Subsonic Speech costs [5] (if separated from Subsonic Hearing) and Ultrasonic Speech costs [5] (if separated from Ultrahearing), a Hyperfrequency Speech trait would cost ...? Component costs are either [10] (if hearing is bought separately) or [20] (if hearing is included), but, well, Hyperspectral Vision has that bit where it costs more than it should ...

[lexington]

Originally Posted by Sunrunners_Fire

Subsonic Hearing (Basic Set, pg 89) allows the character to hear sound frequencies under 40 Hz. Erm. Human audible range goes down to 20 Hz. Anyone know why Basic Set assigned 40 Hz as the cutoff point?

This is a equal loudness chart:
http://www.duke.edu/~jak21/range.jpg

As you get close to 20Hz the the threshold of hearing gets extremely close to the threshold of pain. What this means is that at 20Hz you can only hear sounds at very close to 120 decibels (most other charts are more generous than the one shown here), much lower and the ear cannot detect them at all, much louder and the motion in the organ of corti will crush receptor cells leading to extraordinary pain and loss or hearing at that frequency. You do have hearing at 20Hz but only barely.

In reality there's no defined meaning for infrahearing so the setting of the line in arbitrary. GURPS sets it allowing a degree of overlap with human hearing. There's nothing inherently wrong with that.

Originally Posted by Sunrunners_Fire

Hyperspectral Vision [25] combines Infravision [10] and Ultravision [10] into a single trait while increasing the vision bonus to +3 from +2. I'd count that as Acute Hearing 1 [2]. I'm missing [3]. What bit am I missing to account for those points?

The bonus to Forensics, Observation, and Seach is better than Ultravision gives. The bonus to Tracking from Infravision works all the time rather than for one hour. The perfect night vision applies at all times rather than only for beings that emit heat. And of course being able to say, "Don't worry, ma'am, I have HYPERVISION" is worth a perk.

[Sunrunners_Fire]

Originally Posted by lexington

The bonus to Forensics, Observation, and Seach is better than Ultravision gives. The bonus to Tracking from Infravision works all the time rather than for one hour. The perfect night vision applies at all times rather than only for beings that emit heat. And of course being able to say, "Don't worry, ma'am, I have HYPERVISION" is worth a perk.

Ah, I see. In which case I don't have to take into anything else into account for the traits I want to combine. Works for me!

[vierasmarius]

The text of Infravision implies that it needs to be "switched on" (though presumably as a free action). While Infravision is active, the character cannot see colors. Likewise, a character with both Infravision and Ultravision would need to choose which was active at any given time. With Hyperspectral vision, all three vision modes (Infra, normal, Ultra) are combined into one (hence the higher skill bonus) and are active simultaneously.

[Anthony]

Hyperspectral vision also includes night vision 9, for situations where visible light really is what you want.