First, Dave gave that feedback right after receiving the phones and I can't see how they were not burned in yet. As many times as I state this most people don't burn the phones in and judge the bass right away, it takes 100+ hours, and it does change. It's not an epic increase in bass but it's real and you'll hear it, out of the box it's slightly over-damped and the decay is too quick and amplitude is slightly increased as it settles (the point being you'll probably want to try it again after burn in, and while your mind may not change you'll at least know you're hearing what you should be).
That said, the topic is hugely complex, and to answer it I have to write a tome. These factors inter-relate so YMWV.
1) ETHER has a stronger upper bass to lower mid region, they're about the same in the bass fundamental region, and ETHER C has more sub bass. From about 140-300Hz, ETHER has up to 2-3 dB more output than ETHER C, and below 50Hz ETHER C has about 3-5dB more output than ETHER. I find ETHER's upper bass is slightly warm of neutral, where C's will comparatively sound leaner in this region. BUT how you experience this depends on your listening level and the choice of music...
2) Level: true sub bass is less audible until you increase volume to about 80dB, and as that is a safe level for long listening and it's also where you start to hear sub bass clearly (read about volume and bass perception
here) so I optimize for 80-85dB. Perfect point to both hear the bass and be able to listen for a long time. I assume most customers for a headphone like ETHER value their hearing (seriously) and intend to have it healthy and don't listen at 95dB for four hours.
As volume affects perception of lows and highs, a designer *must* pick a point to optimize voicing. I voice the headphones for 80-85dB because that's where the ear is most linear yet the SPL are safe for a long session. If you listen below 80dB ETHER has more perceived bass because your ear just won't pick up the sub bass (EQ can easily solve this) and not only will it play the harmonics louder, and at frequencies you'll clearly hear them as louder. As you hit 80dB ETHER C gets the more power on the bottom, but even then the harmonics are leaner, so you'll feel more power but depending on how you listen you may HEAR louder because you're queuing off overtones. This latter is my theory after discussing this with many people at meets and seeing how they react. This also heavily influenced my releasing the tuning kit, because it making the loudness dependency more flexible.
3) Content: Is there actually any sub bass in your music? Most pop music has little or no sub bass, true sub bass is really only for EDM. If you put on pop or rock and compare, ETHER has more bass at a comparable volume, for the reasons outlined in #2. However, if you put on EDM and turn it up, ETHER C per #1 above ETHER C will have more of a foundation. In real terms, the typical E string of a 4 string bass is tuned to ~41Hz, low enough so at low volumes you would usually hear more harmonic than fundamental but you will hear the lowest notes having a more solid bass on C, even while possible sounding not as loud due to the harmonics. Confused yet?
4) A lot of what people hear in bass is overtones and THD (THD can be thought of as emphasized overtones). ETHER C's sub bass has very low THD and that, combined with the leaner upper bass presentation than ETHER means that if you AB ETHER vs ETHER C you will almost always say ETHER has more bass if you are weighting the overtones that are more audible more than you are the fundamental, but if you listen for the real pressure waves, the fundamentals, ETHER C whomps ETHER, and if you listen to acoustic bass at say 85-90dB I think many people will hear that C has more presence and resolution.
5) If you aren't getting a good seal on the C you won't get the sub bass, that's just the physics of it. The deeper bass needs a good seal. Thick hair that doesn't press flat or glasses will kill sub bass.
I've watched experienced listeners and reviewers get tangled up on this, it definitely is source and volume dependent, and it also factors WHAT you listen for, the harmonics or the fundamentals? Many people hear the harmonics first, I think.
It's a remarkably complex subject and there are no easy answers. Many times it comes down to simply how loud you listen and what you listen to. If your meat and potatoes is classical or jazz you may well prefer ETHER's bass, but for EDM or as an all around (because I love EDM) I go with C because I love the feel of the pressure wave, even though you can barely hear it you can feel it, and it's there at the levels I like to listen, and with a lot of what I listen to. I tend to listen at 80-85 dB.
So to get the most bass out of ETHER C:
1) Use 2 black pads or 1 white. This truly makes a noticeable difference by allowing the upper bass to have higher relative prominence, 1 white pad on each side gives me that "Funktion 1" sound I like.
2) Don't be afraid of EQ, digital EQ can be excellent in a good player and both ETHER's have very low THD and excellent transient response, so they take EQ really seamlessly. Using Parametric EQ just add 2dB from 140-250 or 300Hz and you will probably immediately say ETHER C has more bass at any level. To Parametric EQ ETHER add 3-4 dB below 15-50Hz.
3) Listen at 80dB plus on ETHER C. 80-85dB is safe for extended listening, but louder you need to pay attention to your levels and how long you listen for safety.
4) Remember ETHER C will have a more powerful feel to the deepest bass, but that you will hear the overtones on ETHER more, so how you listen and experience will have a big impact.
So summing up, I voiced the headphones so most people would like both but everyone would have a preference, this is part of that. I don't think there's a right answer, but for the record, I used to play bass, and I love the instrument dearly. For me, it's C for most music, except jazz where I often prefer ETHER.
Regarding your preference for the Alphas, look, maybe that's just your preference, there's nothing wrong with that. I've had people prefer the Mad Dog to the Alpha Prime, though that has only happened twice. So if you prefer the Alpha save some money, or decide to upgrade and use EQ because ETHERs love EQ and you can pretty easily hit that curve, but now with much greater resolution. EQ can't fix a bad headphone, but it can do wonders to dial a solid headphone to precisely fit your tastes, and EQ is improving quickly in quality on a lot of the good players.
Just remember, you asked.
Now that I've answered this I expect about 80 questions, so fire away. I have more C's to build tonight, so it may be a while... Hope this wasn't too confusing, I did not have time to truly copy edit. If anyone spots errors let me know...
