Hi folks. I've been reading here for a few years and have learned a lot, I thought I'd share a cheap but effective headphone EQ setup that I've just started playing with. This is obviously targeted at people who need to EQ external sources, and can be used on loudspeaker systems also, not just headphones.
It uses an iOS app called AUM, which is a host for AUv3 instruments and plugins. But it has built in effects, one of which is a parametric EQ plugin. AUM can host 10 plugins per chain, which gives you 10 EQ slots if you just use a single chain, but if you send the output of the chain to a mix bus, then use that mix bus as the input to the next chain, you can have quite a few EQ slots running at once. I don't think you'd run out of slots for typical applications, or DSP headroom on even an old iPhone 5. EQ profiles can be saved and recalled, and there are other parametric EQ plugins that can be purchased you prefer to be able to see the curve.
The setup below cost me around $25USD. The interface was an eBay bargain, and the iPhone 7 was given away as it has a faulty audio IC, which is not an issue when running an external interface. Any USB class compliant interface will work. One potential downside is battery swelling due to holding the charge at 100% with some heat from the processor. (side note, the IU2 footprint is pretty much identical to that of the ATOM+ amp, which makes for a neat stack)
It uses an iOS app called AUM, which is a host for AUv3 instruments and plugins. But it has built in effects, one of which is a parametric EQ plugin. AUM can host 10 plugins per chain, which gives you 10 EQ slots if you just use a single chain, but if you send the output of the chain to a mix bus, then use that mix bus as the input to the next chain, you can have quite a few EQ slots running at once. I don't think you'd run out of slots for typical applications, or DSP headroom on even an old iPhone 5. EQ profiles can be saved and recalled, and there are other parametric EQ plugins that can be purchased you prefer to be able to see the curve.
The setup below cost me around $25USD. The interface was an eBay bargain, and the iPhone 7 was given away as it has a faulty audio IC, which is not an issue when running an external interface. Any USB class compliant interface will work. One potential downside is battery swelling due to holding the charge at 100% with some heat from the processor. (side note, the IU2 footprint is pretty much identical to that of the ATOM+ amp, which makes for a neat stack)