Financial ratios are relationships determined from a company's financial information and used for comparison purposes. Examples include such often referred to measures as return on investment (ROI), return on assets (ROA), and debt-to-equity, to name just three.
Tremolo harmonica. Tremolo harmonicas are a type of harmonica, distinct by having two reeds per note. In a tremolo harmonica the two reeds are tuned slightly off a reference pitch, one slightly sharp and the other slightly flat. This gives a unique wavering or warbling sound created by the two reeds being not exactly in tune with each other and difference in their subsequent waveforms acting against one another.
Harmonicas come in a variety of keys (click here for more about harmonica keys and note names). The most common harmonica key is C, the notes on a C harmonica are shown below. In the diagram blow means the note when blowing into a hole, draw means the note when breathing in.