Welp, decision day for me. Keep LCD-5's or go back to LCD-4's.
LCD-5 - Why I'd keep it.
This is going to be a hard decision for me. I enjoy the refinements made to the new flagship LCD-5 in resolution and detail. Somehow the highs are airy and crisp without ever being fatiguing, and I am *very* sensitive to sharp/sibilant highs. Where I had to part with the LCD-4z because the sibilance was too much for me, the LCD-5's exceed the crispness and clarity of the 4z's without ever becoming uncomfortable. It's right at that edge, but never goes over that edge. Perfectly executed, in my opinion.
Additionally, it EQ's quite well. I can get the sound mostly how I want it on days when I want more warmth, no problem. It warms up pretty nicely with some love from Peace + EqualizerAPO. As such, it becomes great for movies, games, and similar applications.
The weight is fantastic as well. A great upgrade that started with the 4z's, these being lighter matters. While my neck is very much used to all-day wear for the LCD-4's after years of doing so, less weight will never be a complaint. And similarly, them appearing smaller certainly makes them not look quite as ridiculous on the head during Google Meet team calls. Fit has been good, not too tight on my head. I can wear them for 10 hours without fatigue.
LCD-5 - Why I'd send it back for my LCD-4's
The max potential of the bass's volume and impact is demonstrably less than the LCD-4. This is not news to anyone paying attention, but it bears repeating for the bass-heads in the room: the bass does not and cannot match the LCD-4's.
The gravity of this decision by Audeze is a function of the music genres you listen to. Looking at comments and discussion, it's clear that most of the audience here is not particularly into any heavily electronic genres. There has not been much listening and commentary going on among those of us who prefer genres like Hip-Hop, EDM, or other genres where bass is a primary catalyst for the emotion of the track. And in fact I've more frequently seen their needs and goals dismissed by other posters here which neither helps them nor brings clarity to the issue. (Sidenote: This is a content gap that someone on YouTube could make a lot of money filling, quite frankly. High-quality, professional reviews from a bass-head's perspective would speak to the interests of a lot of people.)
It makes sense from a business perspective to tune your product to the typical persona of the audience you're looking to sell to. The goal of a business is to make money and the money that can drop $4000+ on a pair of headphones probably skews a little older and probably towards certain genres. Maximizing the experience for those genres gives you a clear path to profit in that space. Duh, right? So while the cans sound exceptional with Rock, Alternative, Classical, and can be EQ'd to get a lot out of R&B, hip-hop, EDM and similar...they can only be EQ'd so much before running into real trouble with distortion on my amp (v281). At more than +4db in the <100Hz range, the bass starts to fall apart on the tracks that I use to test bass limits. Maybe my amp just isn't good enough for these cans? I don't know. But I do know that it's been perfect for years with my LCD-4's and I'm not interested in upgrading the amp to accommodate them. They come up short of what the LCD-4's can do here with some EQ. The LCD-5's can sound deep and rich. The LCD-4's can shake the earwax out of your ears.
Just as there are things that the LCD-4 can't do that the LCD-5's can...this is a particular area where the LCD-5's can't do something that the LCD-4's can and it becomes a real drawback for someone who is closer to the "bass head" side of the balance scale and has been enjoying that aspect of their LCD-4's for many years. For tracks in which the slam itself is a critical part of the emotion of the song, the consequence here is that the song itself becomes a less exciting and emotional experience. For the impacted songs, they are losing something in going from LCD-4 to LCD-5. As of this post, I'm still hoping to find the EQ setup that gets me a bit closer to the LCD-4's, but after almost 2 weeks of fiddling (and trying all posted EQ's), I just don't think there is an EQ setting that closes the gap like I want it. Not for my equipment and maybe not for anyone's equipment. It just has a lower limit for and tolerance of powerful bass. I'd say it gets about 80% of the LCD-4's bass response, give or take. How much that 20% matters is a function of how much of your music/movies reaches out and requests access to that kind of bass quantity and impact. It can make a huge difference in the experience.
Who I think the LCD-5's are for and not for
If you enjoy a diverse selection of genres as I believe many of us do, I think the LCD-5's may be the best cans available if your goal is owning one set of cans. For those who played Street Fighter, I'd describe the LCD-5's as the Ken/Ryu of the headphone market. Really good at everything, though not necessarily the best at any one thing. A combination of good things that you can't get anywhere else in the same quantities. As such, you'll have little to complain about with these cans. For those who only want to own one pair of headphones, I find these would be hard to beat. Plus, new engineering hopefully means further improvements to reliability. I think many past LCD owners can attest to driver failure being an issue. I just had my LCD-4 drivers replaced in March, so I'm sensitive to this also being a potential selling point of the upgrade.
...but for those whom find hip-hop, EDM, or R&B or similar genres represent an outsized portion of your listening time with headphones, these might not be the move. While I find the LCD-5's to be excellent for all of those genres as well, a well-EQ'd LCD-4 will give you more of an emotional experience which will translate to a more enjoyable experience with your music. And for considerably less money. LCD-4's are just a richer sound for those richer musical genres. The LCD-5's are well-tuned an improved experience across most genres, but I feel it comes at the expense of the best experience for the aforementioned genres. For the bass-head audience, you will almost certainly find that the LCD-4's or 1266 TC's to be *better tuned* for your genres.
Am I keeping my LCD-5's or are they going back?
Well, I'll be making a decision in the next couple of hours. I'm really not sure what I want to do. My music genre balance is something like 70% electronic genres (EDM, hip-hop, R&B, gaming), 30% everything else (rock, classical, jazz, ambient, gospel) and that 70% really benefits from the sound profile of the LCD-4's. Further, the LCD-5's not being a clear upgrade for 70% of my listening experience is not helping justify the spend. If I use that as my measuring stick, the math becomes pretty simple in favor of the LCD-4's. But the clarity and resolution alone make me wonder if I should keep the 5's and buy back my 4's to have both. The only times I wasn't using my LCD-4's over my other cans over the last few years has been when I'm on a trip or when they've been out for service/repair so they are near and dear to me.
I'm also intending to pick up a pair or 1266 TC's (yolo) before end of year when the prices go up and am unsure if the combination of owning both the LCD-5's and TC's even makes sense. So yea. I'll have made a decision in the next 3 or 4 hours. After waiting so long for the delivery, I wish this had been a clearer upgrade for my typical listening experience. I wish I had both the 4 and 5 together in a room so that I could really do an A/B and decide which is best for me. Perhaps I can talk with the team at Audeze and send them another $2k to hold so that I can spend a week A/B'ing both these 5's and my old 4's and make a decision that I know I'll be comfortable with. It's tough to A/B cans from memory, but I know I miss my LCD-4's.
Anyway, sorry for the long post. Back to listening and hoping to get past this paralysis of analysis.