Touch upâs should be done minimum 4-6 weeks post the initial treatment. This allows time for eyebrows to heal fully before perfecting them for the second time. Free touch-ups are only valid up to 3 months from initial procedure date.
Re: The Tinny sound? Most folks that are concerned about a tinny noise with aluminum boats are referring to the noise generated by the hull moving through the water (which can be modulated/reduced through many different avenues). You mention vibration and rpms, so I'm guessing that you're not referring to that sound.
Does your piano sound bright and tinny? Hereâs why. Each time a key is played, your pianoâs strings are struck with a hammer composed of highly compressed wool felt. With time and usage the hammers become harder and develop grooves causing the tone to change â often to one that is brighter, and sometimes harsh or tinny.