Two things:
- Infrasound is notoriously hard to locate so it doesn't matter where the speaker is hidden.
- The Infrasoundgenerator has a capacity rating, so you can by RAW install it in a limb - which in this case is also realistic: Your larynx just isn't big enough to contain a speaker that can create infrasonic frequencies.
Also, unlike the voice modulator this piece of cyberware doesn't need to be connected directly to your voice box. A simple microphone will suffice so it activates when you speak. (Yeah, I actually did think about this ^^)
