I think I've done ONE non-IEM gig in the last 3 yrs. It was strange.I have triple driver iems now, interesting to get that perspective from someone who went from 3 to 12. Can you really hear that much more definition? i'm sure the cost was a lot, justified? can you elaborate a bit? thanks.
Earlier this year I went from 4 to 8 drivers (customs) with the 4 driver having dual LF, 1 Mid and 1 HF driver to the 8 having 4 LF, 2 mid and 2 HF drivers
YES !! categorically better bass, mids and highs due to crossovers and that more BA drivers tends to give better quality.
My 8-driver buds use the ADEL tech (now called APEX) which has a "pneumatically interactive vent" [diaphragm] in each ear to equalize the ear canal pressure one gets from customs. Almost like an ambient port. There's a little less isolation with them compared to the 4-driver which does NOT have them.
I have few issues hearing other band members on stage.. and with a stereo mix I have full control over what I hear in the mix, and where I pan it.
I gig frequently, so the price > $1000 was worth it, and yes, the band got endorsing artist discounts on upgrades. Custom molds will give you far better "seal" than universal fit, but with an appropriate price increase.
BTW - I'M A HUGE PROPONENT of IEM's !!
One cheaper approach for customs is to check out the "for sale" items (used customs) on headfi dot org. You can get them at GREATLY reduced prices, then pay to have the vendor re-shell them ($200-350) to fit your ears. Can be significantly cheaper than buying new.
Oh, and to stay on topic.. I have never noticed any degradation in sound with wireless going into my Axe, and I have done 100's of gigs using a couple of different wireless units (AT, L6 and Senn) over the last 7 yrs.