Some Android devices (mainly HTC) don't have the "Audio Effects" Option under "Settings."
From the original thread:
"We've had some reports of people using some HTC devices with Beats Audio not being able to use the Audio Effects options. I'm collating some information for some reporting. Could you confirm the devices you are using that you are not able to use the Audio Effects option on?
If you're not using a Beats Audio-enabled device, I'd recommend trying a clean installation first, and see if they are available now. If they aren't, could you pop that below too, stating that it's not a Beats Audio enabled device but you're not able to use the Audio Effects option."
August 2014 - This issue appears to also now effect certain LG devices such as the G2 and G3.
Many of you have been asking about why the Equaliser isn’t available in your Spotify Settings. On Android devices, the setting only links to the Equaliser in your device’s Android settings. If your device’s hardware manufacturer doesn’t have an equaliser, this setting will not show in Spotify.
Since this is a software choice made by a manufacture, we will mark this thread as “not an issue” and close the topic soon.