The Short Time Fourier Transform (STFT) is used to identify time localized frequency content of a signal. The STFT operates by chunking an input signal into blocks and performing FFT on the block, and then recording the frequency coefficients for that point in time. However, the STFT enforces fixed time and frequency resolution which is not always desired.
A wavelet transform is an alternative method for identifying the frequency content of a signal where the window size typically varies based on the frequency, thus creating an inverse relation ship between time localization and frequency localization. That is: high-frequencies have good time localization but poor frequency localization, and low-frequencies have good frequency localization but bad time localization.
Let's say I want to use a wavelet transform as an alternative to the STFT. What specific wavelet should I use? Do some wavelets work better for encoding frequency content?