The Noble 4C ($699) is a quad driver design in the same vein as the Heir 4.A, which means a three way crossover, dual low frequency drivers, and separate drivers for mids and highs. I still have my 4.A and still enjoy the heck out of it, as a mostly neutral, but slightly forgiving model with very broad appeal. But I gotta say the Noble 4C is probably better for most people. Those who remember how much I enjoyed the 4.A will know how big of a statement this is.
Why? You may recall some complaint about the 4.A having a rather potent "dip" in the response centered around 4kHz. This was measured in the 4.Ai which was the universal model, and I have to say I did hear that fairly prominently. I never thought it was the deal breaker that some made it out to be - in fact that was not even my biggest complaint about that particular model. My custom 4.A doesn't have nearly as obvious of a dip - if it's there, it's very slight. It could be my ears glossing it over but I'm inclined to think otherwise since I did hear it in the universal model. Regardless, Wizard tweaked things in the Noble 4C to account for this 4kHz dip, so depending on your perspective the frequency response will now be flat, or (comparatively) slightly boosted in my case.
A quick word about aesthetics. As usual, Wizard has done an amazing job. My 4C is done in a great dark purple color, very slightly translucent but hard to see inside due to the color depth. It's got some type of gold threads or something in the faceplate, very very cool looking and unique. The effect is better in real life, and my amateur hour photography simply does not do it justice.
Despite not having any complaints about my Heir 4.A, I really do enjoy the Noble variant a bit more. Note that we aren't talking about a massive difference - they are both cut from the same cloth, but the focus is somewhat shifted here. The new sound is something I might describe as a junior version of the JH13 FreqPhase - mostly neutral with just a bit of added energy or excitement, making the experience rather engaging as a whole. The Noble 4C has very nice bass performance that lies somewhere between true neutral and the slightly more robust impact found in the JH13. The more expensive JH13 seems to have more sub-bass impact which is welcome, but the 4C isn't too far behind. I'm not sure what Wizard did to tweak the bass, or if perhaps it's a byproduct of the general tuning on this new model, but it seems to draw slightly more attention to itself this time around. Not a lot mind you - this still isn't a bass monster. It has more impact and perceived extension than the Etymotic ER4 models though, and more than the Heir audio Tzar350 if anyone is familiar with that unique sounding model. Compared to the Heir 4.A I feel like the Noble 4C is very slightly more textured and robust in the lows. For all I know this could come down to standard variation between drivers, but that's how I hear it.
The main change from 4.A to 4C seems to be detail. Where the 4.A was slightly on the forgiving side at times, the 4C is more ravishingly detailed. By that I mean it comes across as having more sparkle, more "bite", in those upper registers. Just like the JH13, this results in a more exciting, involving presentation which really grabs your attention and refuses to let go. Note that this is not to be confused with "brightness", which is not a word I'd choose to describe the 4C at all. I never get a sense of things sounding shrill, and rarely do I get sibilance that isn't already there in the track. Much like the JH13, the 4C prefers good recordings but is not ultra-picky about it. I can still enjoy average quality stuff such as the New Amsterdams, Jimmy Eat World, Murder by Death, and that sort of thing. Yet when I play some really well done music - Reference Recordings, JVC XRCD releases, MFSL - the Noble 4C really scales well. Truly poor recordings - Death Magnetic and Californication and the like - are practically unlistenable experiences. Which is unfortunate, but pretty much how it should be given a transparent headphone. So if you tend to listen to a lot of newer, highly compressed, radio-friendly stuff, these may not be a good choice at all... though I can't imagine you'd buy this nice of a CIEM if that was all you intended to play.
Speaking of scaling well, the 4C is excellent for home use with high end equipment. Not that I don't enjoy it on the go, mind you, but with a highly resolving IEM such as this, better gear pays dividends. I start with something simple - iPad, Sansa Clip+, and the result is reasonably enjoyable. Nothing amazing, but pretty good. Switch to an older (and better sounding) iPod 5.5g and running an LOD to various portable amps, the Noble 4C responds accordingly. Go all the way up to the HiFi ET MA9 (an obscure but killer sounding high-end DAP from China) or the iHiFi 960 feeding digital out to a Leckerton UHA-6S mkII, and the 4C definitely reaches a higher level. At this stage the 4C is notably superior to all the budget oriented customs in my collection. Yes, it's more expensive than the $400 or $500 dual/triple driver models, but it's worth it if you have the gear to take full advantage.
At home, the 4C just continues to impress. The 30 ohm impedance and moderate sensitivity (for an IEM) mean it doesn't require much power at all. The only real limitations here are the same as most other IEMs - a low output impedance is essential, and some powerful amps have too much gain or noise. Nothing unique about the 4C in this regard. I use it straight from my Anedio D2 or Resonessence Invicta with fantastic results. The Yulong D100 mkII does a great job, especially for a reasonably affordable device. My Violectric V200 is also amazing - despite being a very powerful amp, the noise floor is practically non-existent, especially with the pre-gain switches turned down low. The other more potent (and mostly Class A) amps in my collection don't do as well though. Yulong's A18, the Auralic Taurus mkII, and the Questyle CMA800 all have moderate hash or hiss thanks to their higher gain, so none of them is really ideal. My favorite though, in terms of real word scenario and matching what a typical consumer would probably use, is the Resonessence Labs Concero HP. Straight from a MacBook Air over USB, this brilliant little DAC/amp has loads of resolution and plenty of musicality to make the 4C a highly satisfying listen. At under $1600 for the whole shebang (not including the Mac of course) this combo approaches the best I've heard for a "reasonable" price. A very impressive combo that I can recommend highly enough.
So is the Noble 4C always better than the Heir 4.A in every circumstance? No, I wouldn't go that far. The Heir is still a great CIEM and has its own charm. Those who might prefer a less energetic presentation might do well to stick with the original model. As I mentioned, the Noble 4C is something like a junior version of the JH13 FP, while the Heir 4.A is very similar to the Frogbeats C4 if that comparison helps anyone. They both have merit. That being said, I prefer the Noble model in most cases.