This course consists of the explanations of popular adjectives used to describe audio.

1. Dark - this means the signal sounds vintage, to understand what vintage sounds like listen to some old recording and study the tone. Dark sounding also falls under colored.
2. Bright - this means the signal has more high frequencies. If you want to make something sound brighter add some high frequency to it. Bright being the opposite of dark can be great on some vocals.
3. Clean - clean means your signal is pure and accurate. This is a modern sound, the opposite of vintage. For example a clean mic pre means it doesn't change (or color) your sound. So what you put in is what you get back. Solid-state or transformerless is generally clean.
4. Colored - this is the opposite of clean. Coloring your sounds means changing the tone from the original signal. Colored can be associated with vintage and sometimes dark. Different gear has different colors. If you listen closely you can hear differences between different pieces of gear.
5. Muddy - this the second hardest term to explain, but here we go. Mud is a build of low mid frequencies (200-500hz) that makes the signal sound cluttered. Mud is not a positive thing and should never be taken as a compliment. It took me a long time to distinguish what mud was.
6. Sterile - sterile means ultra clean. This is good for say orchestra where you usually want as little color as possible. Sterile can also come off sometimes as “too clean", meaning its so clean it's boring. These type of pres are crystal clear though.
7. Transparent - this another word for clean and it's mostly associated with compressors and eq's. A transparent piece of gear means its not going to impart any color on the original signal during its processing. If you're happy with the tone of your signal but need to further process it then you need to reach for something thats transparent.
8. Smooth - this to me differs in compressors, eq's, and mics. For compressors smooth means its compressing but you can't really hear the compression, even at high gain reduction. Any compressor, except maybe aggressive ones (more on that next) can be made smooth with the right settings.
9. Aggressive - in a mic pre this means in your face, very forward sounding. The API 312 and 512 have been described as an aggressive mic pre. In a compressor this means it really clamps down on a signal even with gentle settings. FET compressors are known for being aggressive and being capable of a very fast attack time.
10. Warm - this is the one you all have been waiting for. Warmth is the most used word when describing the sound of a piece of gear. Its the hardest one to describe because people who have no idea of what warmth is use the term freely. So what warmth is to you and how you perceive it will be different from others because the term is used so loosely. Where bright deals with high frequencies, warmth deals with the low to low mid frequencies. Tubes are associated with warmth because they add harmonic distortion (the good kind of distortion) to the those frequencies. This is what people are referring to when they say tube warmth.