The Earsonics Velvet is the most versatile IEM that I have used to date. Depending on the source you attach them to, you can tweak the tonality and sound signature to cover just about any genre you're hoping for. The Velvet always has a midbass presence that is hard to tame, but with the right amp and settings you can make a very large sound presentation with clarity, detail, and musical richness that I cannot find with other IEM/portable amp setups.
With just the iPhone6 I move the sound signature potentiometer to the Middle setting. I find that the iPhone barely has enough power to make the Velvets feel powerful and present. By adding a little warmth to the Velvets I can manipulate the thin sounding iphone to a slightly punchy 'house' feel. By adjusting this potentiometer to normal and eventually to warm, you eventually lose out on a bit of the space/air in the presentation. This is both a fault of digital volume adjustments of the iPhone and the amping of the signal inside the potentiometer itself.
The Velvets can handle a lot more power than the iPhone can offer, and while it is slightly sensitive, the Velvet benefits from a neutral and quiet amp.
The 2 amps that I frequently use with my Velvets are:
the FiiO E7 (which I use primarily for the 2 headphone jacks, so I can listen to music with my friends) - The E7 adds some warmth, depth, and power, but scales the sound down to a bit darker, and a bit warmer. The Bass settings are aggressive and I use a flat EQ signature with the E7 and tone back the Potentiometer back to Tight. With the added power and warmth of the E7 the Velvets do not require its own warmth, and the Earsonics Benefit more from the soundstage of the Tight setting. By using the E7 from FiiO and the Tight setting on the Velvet's I maximise the soundstage, minimize the added warmth/dark signature of the E7, and add enough headroom to get a loud presentation all across the frequency range.
My favorite pairing with the Velvet's come in the form of the iBasso P5 Falcon, however.
The iBasso P5 Falcon is a powerful portable amp that has a desktop power module as well. The powerhouse of the P5 with its many adjustments and tweaks allow for an amazing pairing and customization with the Velvet. The P5 Falcon has (3) gain settings, (2) Bass settings , and you can modify the Buffers and OPAmps they use internally. The pros and cons of these 2 systems, the P5 Falcon, and the Velvet's compliment each other very very well. With just the default amp/buffers inside the P5 , with the Gain and Bass settings to "low" the Earsonics sing beautifully on their Tight setting. The P5 Falcon is so quiet and the buffers and opamps match so well that it sounds as if the P5 normalizes all the frequencies to have the same amplitude in volume. Each frequency range presented sounds equal in its display. Now you can modify the bass/midbass tones with your Velvet's potentiometer. You can increase the level of treble focus and timbre by switching out the opamps/buffers. You force the amp to be darker or warmer, and you can change the Velvet's to add/remove soundstage. It's a beautiful combination.
Currently I listen to my P5 Falcon on its default amp/buffer combination, with my Velvet's in Tight presentation, and if I want more Bass, I flip the switch on the iBasso amp, gaining some midbass presence without restricting the soundstage.
The Velvet's chime beautifully with a powerful and quiet amp.
So happy!