Midrange - While not the standout point of the Custom Art Ei.3 the mids are what I would describe as balanced and accurate. There is not extra push given to them and they aren't as lush or intimate as one might find on say a universal earphone like the Dunu DN-2000 or a my current favourite earphone the Campfire Audio Lyra but the mids on the Ei.3 are what I would consider monitoring level accurate without any extra flavour added to them. This works well in male vocals and some acoustic guitar pieces where too much warmth can result in an overly thick appearance of a performance, the Custom Art did very well. Speed in the midrange was observed to be very responsive and the EI.3 performed admirably in Tchaikovsys 1812 Overture that has been the downfall of more expensive non custom earphones such as Flare Audio's R2Pro. With the above in mind I would say the Custom Art monitors have good detail, speed and accuracy but are not to be considered a warm / lush earphone with regards to the midrange at least.

Lows - Lows are strong and responsive pumping out the deep notes with incredible levels of speed, detail and texture but, all out bass canons, they are not. Theres none of that monstrous sub bass slam that you will find on a set of RHA T10i (universal earphone) or the Dynamic Driver Aurisonic AS2 (Custom Monitor). Sub bass is notoriously hard to pull out of a balanced armature earphone due to the simple physics and the amount of air the technology is able to drive into your ear canal but ill tell you that Custom Art have done an incredible job of going as low as this on a 3 BA (balanced armature) earphone. The control was and tightness meant that there was no real slippage of the lower frequency into the mids. This feature thus allowed the bass to set the pace in EDM (Electronic Dance Music) and let the rest of the frequencies do there thing.

Soundstage & Separation

The soundstage on the Ei.3 is OK its not big but it also doesn't feel overly closed in. Its one area that I can see the advantage of going to a higher priced monitor, perhaps something like my own UM Miracles. Separation is good with plenty of clearance between instruments its not a fully immersive presentation like on more expensive earphones though where you will be given that 3d imaging that will fully captivate you. Again this I think price has to be mentioned here because at sub $300 they are up there can be considered good to very good when it comes to soundstage, separation and imaging and only when you get to the real TOTL CIEM's do you find a significant improvement.

Comparisons against other entry level CIEM

The Custom Art Ei.3 outperformed all my entry level monitors in one way or another. I put them up against my Proguard P2+1, Minerva Mi.Artist Pro, M-FIdelity SA-12 and I found the overall signature of the Custom Art units to be more enjoyable by quite some margin over the Proguard and M-Fidelity units.

Vs the Proguard P2+1 I preferred the overall clarity of the Ei.3 with it sounding more open and detailed than Proguards. Bass rumble was deeper on the P2+1 but lost out in bass texture and detail. Highs weren't even close the Custom Art were far better.

Vs the M-Fidelity which are in my opinion a massively overpriced, single driver, poor fitting pile of ... The Custom Art Ei.3 absolutely walk this comparison the two aren't even in the same league. Whats even worse is that M-Fidelity see fit to charge buyers double the price of the Ei.3 for a far inferior product.

Vs the Minerva Mi-Artist Pro - This is pretty close as the Minerva Mi-Artis are a great set of in ear monitors and one that I hold in extremely high regard. Side by side I would be happy with either from a performance and fit standpoint but yet again the Custom Art Ei.3 dominates on price.