I'm planning on making my first set of DIY IEMs to replace my lost set of westone 4.
After trolling through this huge thread I decided on using the easily available Knowles BA drivers, CI, DTEC and WBFK. I have seen people using the combination of TWFK and CI, but since I like rich mids, I rather go the extra mile for the DTECs, plus the westone 4s use the DTEC and TWFK so I figure this will be close enough with the sub-bass boost from the CIs.
One thing to note about this combination which I have seen, is that some people comment that the WBFKs are less sensitive than the CI and DTECs, hence the highs sounds recessed or the bass and mids need a resistor in series to tame the response. Could anyone advise me on a suitable crossover network for these 3 drivers (resistor values and cap values would be appreciated, or suitable frequencies as I know how to calculate that myself). Alternatively, should I go for dual WBFKs since they’re really small and easy to fit into the shell?
Also, do I need to cascade multiple components to create a bandpass network for the mids? I think I need a minimum of 2 high and 2 low pass to create a suitable network (low pass for subwoofer, bandpass for woofer, high pass for tweeter), but I’ve seen examples with less. Would it be bad to pass the high frequencies to the CI or low frequencies to the DTEC as that might cause problems with interference?
I also considered making an active network in a separate box and hacking a player into it, but that seemed too complicated especially considering the size, but I’ve seen one example in this thread so I might consider modifying it one day to include a suitable network.
I also would like to eventually customise this IEM, but for now I’m going to rapid prototype a universal shell since I have access to a really good machine from stratsys with a lovely clear material. Does anyone have any idea where I can find a online model to base my shell on? I’ve done a simple rounded shell in solidworks to see if it fits in my ear, but doing a more complex model without exact measurements of an existing IEM is too hit and miss for me.
Thanks for helping!