First of all, an EQ doesn't work with an aux send.
There are two different kinds of effects: send effects and insert effects.
- Send effects add NEW sounds to your audio - e.g.: reverb, chorus
- Insert effects modify EXISTING sound you already have - e.g. compression, EQ, voice changer
Send effects use an after-fader aux send and an aux return. Use a Y splitter if the return is stereo.
Insert effects must be used with an insert/return jack that breaks the signal path to insert the device.
(Pre-fader aux sends are for monitor amps and speakers for performers)
A send effect can be used with all of your sound sources. Use the send controls to adjust how much of each gets sent to the effect.
If you want to use an insert device with a single sound source, use the channel strip insert/return connection or put the device before the mixer input.
If you want the insert device to affect all signals, put it in a bus insert, output insert, or after the mixer.
I know that sr32-4 mixer. It has channel inserts (needs special cable) and mixing bus inserts.
If you want EQ on a stereo mix, you must have a stereo EQ unit.