FLC Technology FLC8 and FLC8s Impressions Thread
Aug 24, 2019 at 12:34 PM Post #7,726 of 7,931
The FLC8S is the most comfortable IEM that I currently have, I practically do not notice that I am wearing it.

But, for me, I would appreciate a little more sub-bass and bass, even using the red-black configuration. If you say that the FLC8D has more bass, it would have been a better choice for me, although it is easy to correct by raising the equalizer 3 db in a pair of frequencies.
 
Aug 25, 2019 at 7:48 PM Post #7,727 of 7,931
Normalized at 500 Hz, on account of the peak that the FLC8s has at ~ 1 kHz:

flc8d_vs_s.png

The FLC8s is quite a bit brighter-sounding. If I had a gun to my head I'd choose the FLC8d, but I love both these headphones :)
 
Aug 26, 2019 at 1:02 PM Post #7,730 of 7,931
Normalized at 500 Hz, on account of the peak that the FLC8s has at ~ 1 kHz:


The FLC8s is quite a bit brighter-sounding. If I had a gun to my head I'd choose the FLC8d, but I love both these headphones :)

Which is killing me is that peak at 3,5 kHz . But I am starting to love them even with all that bright.
 
Aug 27, 2019 at 12:01 AM Post #7,731 of 7,931
Is that bass correct in the flc8d? Even when the black filter daaaamn. Could you add flc8s with the gold filter too to the comparison? Pretty cool dark mode graph btw

Look at the reviews from Brooko and HiFiChris for more graphs with different filter configurations: https://www.head-fi.org/showcase/flc-technology-flc-8s.21068/reviews

What's confusing me tho is that in csglinux' graph, the curve goes up after 2kHz, while the curve only goes down after 2kHz in both Brooko's and HiFiChris' graphs:

XwIzZBI.png

Colored = Brooko
Grey = HiFiChris
White = csglinux

Why is csglinux' graph that much different while the other two are at least somewhat similar? (sorry if it's a stupid question, I'm new to this)
 
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Aug 27, 2019 at 2:09 AM Post #7,732 of 7,931
Look at the reviews from Brooko and HiFiChris for more graphs with different filter configurations: https://www.head-fi.org/showcase/flc-technology-flc-8s.21068/reviews

What's confusing me tho is that in csglinux' graph, the curve goes up after 2kHz, while the curve only goes down after 2kHz in both Brooko's and HiFiChris' graphs:

XwIzZBI.png

Colored = Brooko
Grey = HiFiChris
White = csglinux

Why is csglinux' graph that much different while the other two are at least somewhat similar? (sorry if it's a stupid question, I'm new to this)
Not a stupid question at all. There can be a lot of subtleties to this. Generally, you don't ever want to compare results from two different rigs, because there are a whole host of things that could legitimately be different, including:

1) Different types of eartips
2) Insertion depth
3) Unit variation between headphones
4) Coupler transfer impedance
5) Coupler microphone

We know 1) and 2) play a large role in the treble. @Brooko and @HiFiChris are probably not using the Cp100 eartips I'm using. I think Cp100 are more comfortable and sound better (to me) than the stock FLC tips, but I'm not judging. Others have to decide for themselves, because different eartips and insertion depths will give different results for different people. 3), 4) and 5) could cause discrepancies anywhere over the frequency spectrum. To give an indication of 3), look at the variation in the left and right channels of my FLC8s and FLC8d using gunmetal filters:

flc8s_gunmetal.png

flc8d_gunmetal.png

(Note that the previous results I showed were averaged over the L and R channels.)

BTW, somebody else had asked to see results with the gold HF filters. Here they are:

flc8s_gold.png

flc8d_gold.png

And an L/R averaged comparison of the two headphones, both using gold HF filters:
gold.png


You can see that the channel balance on my FLC8s and FLC8d is fair but not perfect. We have to expect some variation from unit to unit.

As for item 4), I believe both @Brooko and @HiFiChris are using what's called a Vibro Veritas coupler. I have one of those too, and they're perfectly fine - but they will give a different response to that of a 711 coupler. (My measurements were using a GRAS RA0045 coupler). Compensation files can help, but you can't expect a perfect match between Vibro Veritas and 711 measurements when hopping back and forth between sealed and ported IEMs.

In my experience, the biggest discrepancies usually come from 5), i.e., the coupler mic, and in my experience, the Vibro Veritas mic is its Achilles heel. It's not particularly flat, even just from 20 Hz -> 10 kHz. Having said that, if you're wanting to know which of these measurements is correct, there's an easy answer to that: none of them. None of them will exactly match the response from your own ear canal. But that doesn't mean these measurements aren't useful. What we're looking for is the trend and any rig (711 or Vibro Veritas) will be able to show you the effect of switching from gunmetal to gold HF filters, or from switching from FLC8s to FLC8d, etc.

As for trying to get individual rigs situated on the other side of the world to compare with one another... actually, we're working on that too :) We have a little touring IEM project which anybody (@Brooko? @HiFiChris?) is welcome to join:

https://www.head-fi.org/threads/ety...phone-for-your-ears-and-your-couplers.908512/
 
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Aug 27, 2019 at 7:53 PM Post #7,733 of 7,931
Thank you for explaining @csglinux! Your graph does seem to make much more sense to me because I get the sibilance/harsh treble right around that 3.5kHz area where only your graph shows a peak but it's still crazy to me that the discrepancies could be so huge even with all those factors you mentioned.

I guess this all just means that any single frequency response graph is completely useless unless you use it in the context of direct comparison to another measurement done on the same rig.
Which really sucks because on my search for the right IEM for me it would be so useful to have definite/consistent measurements of all the IEMs I have owned/heard before so I could eventually determine the sort of frequency response curve I prefer and look at IEMs based on that. I thought that's probably how it goes, but perhaps not.
 
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Aug 27, 2019 at 8:31 PM Post #7,734 of 7,931
In theory, a 711 coupler ought to get closer to what you'd hear than a 3D-printed cylindrical plastic tube (which is basically what the Vibro Veritas coupler is). I'd be happy to drill down on this some more if @Brooko or @HiFiChris are willing to share their Veritas compensation curves with me.

But, yes, your conclusion is sadly correct. There are just too many variables. 711 couplers are supposed to be good (i.e., have a defined tolerance on transfer impedance) up to 10 kHz, but in practice that's only for deep insertion IEMs. The effects of different eartips and insertion depths can be very significant. Shallow insertion can easily cause the half-wave resonance peak to drop below 10 kHz.

Are you aware of @crinacle's database? It's not exhaustive, but all his measurements were made on a 711 coupler, and more importantly, they were all made on the same 711 coupler: https://crinacle.com/graphs/graphtool/
 
Aug 27, 2019 at 8:55 PM Post #7,735 of 7,931
Oh, that crinacle database is great! Unfortunately it doesn't have any FLC8s measurements but it still gives me some perspective. Perhaps if i dig through your measurements of other IEMs I could see if there are any IEMs the both of you measured and how similar the results are to determine just roughly how the FLC8s might fit into crinacle's database and then go from there.
Thank you so much again for being so helpful!

EDIT: By the way, on the matter of harsh treble and sibilance. Would it be right to assume that any IEM with a similar or higher peak around 3.5 kHz (assuming an identical rig, tips and insertion depth) would sound at least just as harsh as the FLC8s to my ears or are there other factors at play to where even an IEM with an overall higher curve/peak around 3.5 kHz could sound less harsh to my ears?

EDIT2: Curiously enough, I don't seem to have an issue with the sibilance/harshness thing anymore. I guess my ears just needed an adjustment period (or perhaps rather a recovery period after all that different IEM and eartips switching in and out on top of probably listening at way too high volumes while testing and comparing my new IEMs) Only in the most extreme examples do I still pick up a hint of harshness, but really nothing bothersome unless I turn up the volume beyond reasonable. Or maybe its all a mental thing. Either way, I'm just now really starting to really enjoy my new FLC8s' =)
I'm still curious about the question in the edit above though.
 
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Aug 28, 2019 at 6:13 PM Post #7,736 of 7,931
A peak shown at 3.5 kHz using a 711 coupler could be considered a fairly reliable indicator of what you'd hear. Couplers and eartips shouldn't have much impact in that region. BTW, @crinacle has basically the same coupler I do, so (other than insertion depth/eartip choice) his measurements should be broadly comparable to mine. The only thing to watch out for is he tries to force a resonance peak at 8 kHz for all his measurements, whereas I just go with whatever seems a natural fit for the IEM. (So shallow-fit IEMs might show a peak at ~ 8 kHz, but deeper-insertion IEMs would typically show a peak at a higher frequency than that.)
 
Aug 29, 2019 at 12:25 AM Post #7,737 of 7,931
https://www.ebay.com/itm/253759655160 (I just saw they're not shipping to USA, just some EU countries. Maybe try and contact the seller if they can ship to you)

As for the bass/subbass, I think the 8S has plenty. Its easily enough for me with grey/grey and too much with red/black so I imagine the 8D would be way too much unless you really like a ton of bass.

The amount of bass/ subbass is defnitely interpreted differently by every individual. Not to mention the impact of the player, source material, and tips. And the volume at which one plays back material. Keep in mind that I never ever use EQ.

I prefer the 8D bass; but even that comes across as bass shy compared to the iBasso IT-01 and LZ-A2.

YMMV
 
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