2022-05-14: Mods master list.
A compiled list of all my mods. Sorted by difficulty.
Easy = no risks to the transducer, very low cost, and children can do this.
Medium = at worst might need to replace a small part (filters, tips, etc), and might need a little bit of concentration.
Hard = Damage to the transducer is possible, proceed at your own risk.
Level - Easy
DIY foam mod
Materials: https://www.aliexpress.com/item/4000920977234.html
Instructions: https://www.youtube.com/watch?v=D06C5KWABrQ
Effect: Reduces peaks in the upper-mids/lower-treble depending on the size used. Might also increase the bass shelf as a side effect. But primarily used when the iem is too peaky and you want a low cost and zero risk mod. (If you are satisfied with the sound, you can put some glue on the foam so it is more secure.)
Filter mod (easy version)
Materials: https://www.aliexpress.com/item/1005002875037663.html
Instructions: Add another layer of filters on top of the stock filter already on the iem. Higher number = higher density → more dampening → higher effect. Can use the XY filters but the filters Tanchjim includes in their iems also work (substitute for the 500 filter).
Effect: Used to reduce upper-mids/lower-treble. Can also affect the bass shelf with a small boost.
Vent mod
Materials: Blutack, micropore tape or: https://www.aliexpress.com/item/1005002584285688.html
Instructions: Put your chosen material over the inner vent on the iem (usually the vent that is the closest to the nozzle).
Effect: Different levels of bass boost, denser = bigger effect. A full seal material like Blutack or regular tape will have the most change. Do keep in mind that with a full seal material, it is likely that pressure build-up will appear.
Impedance mod
Materials: DUNU Original Earphone Impedance Plug Jack/Adapter Converter 75 Ohm /150 Ohm / 200 Ohm — HiFiGo
Instructions: Just connect the impedance adapter to your cable.
Effect: Depends on the iem, usually used on BA or hybrids (with a BA) to change the whole FR.
Koss KPH30i Mod
Instructions: Block 2 vents on the shell using material that gives blocks 100% (I used electrical tape), specifically on the side that is facing the “outside” when you are wearing it.
Effect: Tightens the bass, adds texture with a minor bass decrease.
Level – Medium
Tuning foams
Materials: https://www.aliexpress.com/item/1005002711483821.html https://www.aliexpress.com/item/1005003707507573.html
Instructions: Remove the stock filter and insert a piece of tuning foams (do not need to put the stock filter back on). Do be aware if the stock filter is acting as a dampener or possibly have another filter stacked under it with damping effects. This could mean that you need to take that into consideration before you do this mod, but not a problem if you compensate by just put a XY filter on top of the tuning foams after.
Effect: Mainly reduces peaks in the upper-mids/lower-treble, with the usual bass shelf boost as well, also tends to add some note-weight into the iem and could help with metallic treble timbre.
Filter mod (medium version)
Materials: https://www.aliexpress.com/item/4000741873687.html https://www.aliexpress.com/item/1005002875037663.html https://www.aliexpress.com/item/1005003707507573.html
Instructions: Remove the stock filter and replace it with a regular filter or a filter with damping like the XY filter. For some specific iems (like the CRA), you can remove the stock filter, insert a tuning foam (Sony general version) and then add a 500 filter on top.
Effect: Depending on the iem, the stock filter might have too much damping, thus making it overly warm, bloated, or lacking technicalities. By replacing it with a filter with no damping or less, these issues can be alleviated.
Level – Hard
Knowles damper mod
Materials: https://www.aliexpress.com/item/32580267018.html + https://www.aliexpress.com/item/32697221111.html
Instructions: For some iems, you might be able to add or change the BA damper. Audiosense T800 is one such model. Where you insert a damper in the nozzle with the help of the damper tool.
Effect: Upper-mids/treble change.