Imaging test: phase
I just noticed something I've never noticed before, so I thought I'd drop a quick note of it here in case anyone finds it useful or has any additional thoughts about it.
If you don't like technical discussions, please ignore and leave it for those that do. I've tried to make this as easy to skim as possible, and no, it was not written by AI. Not even a little bit.
TLDR:
I noticed a possible correlation between imaging (maybe of relevance to gamers in particular) and testing for correct phase.
Background:
I recently got a some new flatheads. Specifically for the purposes of this post, the Lun Sheng Aeolian Bells and the Fiio FF1. Both are good btw, but in completely different ways. This post is not a review of either, but I'm happy to answer questions about them.
Neither of them have L/R indicators on the shells, so it's up to the cable to indicate left/right. The Fiio cable has a small Braille pattern of 3 dots, which means "L", to indicate left. I was adding some red/blue finishing tape to make them easier to see at a glance. I was also experimenting to see if I can get another cable to fit on the Fiio, as they use a nonstandard recessed 2-pin (turns out no stock cables fit, but I was able to modify one successfully).
After messing about with the cables (esp the modded one), I wanted to check I had everything the right way round and in phase. I have a few tests bookmarked for this, but I'm coming to a point, which this particular test seems to highlight best (in case you want to try it on some of your own headphones/flatheads/IEMs):
speaker polarity check - test tone - BEATNVISION
Finally getting to the point:
Now, I had noticed from previous listening that the A-Bells have unusually good imaging, which initially I attributed to their U-shaped tuning.
However, when I ran this test, I noticed that on the Fiio, it's actually quite hard to tell whether they are in phase or not. On the A-Bells the difference is instantly obvious. In-phase has a pin-sharp centre-image and out of phase is distinctly coming from both sides at once.
The difference in imaging quality between the two is also noticeable, but not immediately obvious. The difference in this phase test is night and day, which is a useful property for a good test.
I am now wondering if this generalises or not. It could just be a coincidence with these particular flatheads, but it seems that if I can't tell whether the sound is in or out of phase easily, then centre imaging probably isn't great in general.
I should also add that the Fiio has better imaging than just "3 blobs" that the HD6x0 series are known for, for example. But the centre image specifically, is not very sharp, even though in a lot of music it's not all that noticeable, because the position of a singer is rarely pin-sharp anyway.
Addendum:
Lately I have been thinking a bit about good imaging tests for gamers, because people often ask me "is such-and-such good for gaming" and usually I don't know, because I don't play competitive shooters, which is what most people care about. It seems, according to what very limited research exists on this, that the most important thing for gaming isn't imaging in general, but (somewhat counter-intuitively) the precision of the centre image. So if this isn't just a coincidence with these specific flatheads then this could be a quick and handy "is it good for gaming" test.
I would also like to try out this phase test with many more headphones than just these two, and see if there is a correlation with imaging in games, as well as normal stereo imaging in music. So to do that I'm going to need to find a game that works well as a test.
So, if anyone here plays a lot of competitive games and can suggest any decent single-player FPS' that are broadly in line with whatever positional audio engines & SFX are used in games like CS, PUBG, CoD, Apex Legends, Valorant and other stuff people ask about a lot, please let me know. I probably have some things in my Steam library gathering dust.
Also, I suspect that the A-Bells may be the best gaming flathead under $20-ish, but I don't want to make that sort of claim without testing it in some actual games & comparing with some of my other flatheads to see if it makes a real difference.