Cassette tape sound quality is different from other media.
Cassettes have tendencies in sound quality that differ substantially from compact discs or vinyl, so the graphic equalizer setting that sounds best for records or CDs might not sound right when you listen to tapes. The best equalizer settings depend on your speakers, amp, song, the room and, ultimately, what sounds good to you.
Bass
Cassettes tend to have a muddy low range, meaning that you will have to do some adjustments to bring what you want in the low end to the forefront. If you want to give the bass line or bass drum more presence, you can experiment with conservatively raising the 60 to 140 hertz range. The more accurately you can pinpoint the frequency you want to bring out, the better, as raising the low end too broadly will probably result in even muddier sound and could blow out your speakers.
Middle
What to do with your middle frequencies tends to vary by music type. While a common graphic equalizer setting on many home audio systems resembles a "smiley face" -- emphasizing the low and high frequencies and diminishing those in the middle -- it doesn't necessarily represent the best approach for tape. Usually the lower middle frequencies of 100 hertz to 1 kilohertz cause muddiness, but subtracting too much from this range will make your sound hollow or flimsy.
Treble
Cassettes are notorious for tape hiss, which occurs anywhere between 2 and 20 kilohertz. You can make this hiss less noticeable by curbing these higher frequencies, but you run the risk of losing clarity, especially if listening to a vocalist or speaker. As with the low end, the more accurately you can pinpoint the frequency where the hiss is most apparent, the more effectively you can remove it without diminishing sound quality.
Moderation
Except for in extreme cases, users should resist the urge to raise or lower any frequencies past 12 decibels. Doing so will generally lead to trouble, as the cassette is probably already equalized to something close to ideal sound. You'll get the best results by making moderate adjustments and by trusting what sounds good to you.
Tags: sound quality, accurately pinpoint, accurately pinpoint frequency, equalizer setting, graphic equalizer, graphic equalizer setting