7Hz Salnotes Zero IEM Review

[MayaTlab]

Do you know how exactly the preference rating scores are calculated by any chance?

It's in the Harman articles, which I believe you have access to.
"A Statistical Model That Predicts Listeners’ Preference Ratings of In-Ear Headphones: Part 2 – Development and Validation of the Model"
"A Statistical Model that Predicts Listeners’ Preference Ratings of Around-Ear and On-Ear Headphones"
It's a bit different between in-ears and around ears.

 

[markanini]

More enlightning than reading polarizing opinions online: Find out how much Harmans model aligns your individual preference. Rank the IEMs you have owned first. Lookup their Harman score after. For headphones the preference model will follow your personal ranking an estimated ~80% of the time, for IEMs likely less.

 

[IAtaman]

It's in the Harman articles, which I believe you have access to.
"A Statistical Model That Predicts Listeners’ Preference Ratings of In-Ear Headphones: Part 2 – Development and Validation of the Model"
"A Statistical Model that Predicts Listeners’ Preference Ratings of Around-Ear and On-Ear Headphones"
It's a bit different between in-ears and around ears.

It turns out, I do

The scores for the Stealth and HD800S come directly from oratory1990:

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

I looked at it in detail, there are 2 independent variables that affect the preference rating, the std-dev of error curve, and absolute value of the slope of the regression line of the error curve, both of which negatively contribute to preference score.

Looking at the error histograms of both headphones, clearly Stealth has a lot smaller std dev so is the clear winner in that metric. For the absolute slope, HD800S is almost flat while Stealth has slightly larger slope which somehow closes the gap for the std dev score it seems.

When you are training a neural network, it produces these weights and sometimes if the model is small, you expect these weights to have a sense, a meaning of sort. They usually don't yet the model works anyway. This feels like that a bit to me - the deviations from the curve are wildly different but predicted preferences are very similar.

So maybe the preference is not so much about matching the target at every turn. Maybe then it might not be a good idea to look at deviations from the target curve and claim those deviations point to an objectively lower preference? Because, if my understanding is not wrong, it looks like even if a headphone is deviating from the target curve, and doing that in a balanced way that keeps the slope of regression line flat, predicted preference of that headphone might not be very low afterall.

 

[alumnicesar]

So maybe the preference is not so much about matching the target at every turn. Maybe then it might not be a good idea to look at deviations from the target curve and claim those deviations point to an objectively lower preference? Because, if my understanding is not wrong, it looks like even if a headphone is deviating from the target curve, if it is doing that in a balanced way that keeps the slope of regression line flat, predicted preference of that headphone might not be very low afterall.

ah so i was somewhat right. So the slope is much more important than we think

 

[isostasy]

Anyone have experience with the fit of these compared to the Tangzu Wan'er, which has a tiny shell and shallow fit which won't stay in my ears?

 

[Oso Polar]

The target thinks the extra 3 dB bass boost is objectively incorrect and scores accordingly.

Interesting. After reading this review I actually ordered Zero 2 because of this extra bass they are supposed to have compared to this first version that seems a bit lacking in the bass area. Just received them today and first impression is they still don't have enough bass.

 

[markanini]

Interesting. After reading this review I actually ordered Zero 2 because of this extra bass they are supposed to have compared to this first version that seems a bit lacking in the bass area. Just received them today and first impression is they still don't have enough bass.

You are sure you are getting good seal though?

 

[Oso Polar]

You are sure you are getting good seal though?

Apparently not. Changed the default red eartips to yellow (the biggest available) and the sound changed completely. IMHO they sound pretty balanced now, I don't find bass excessive (but at this point I used them for less than an hour). Also, bass extends pretty deep, it goes much lower compared to TRUTHEAR x Crinacle Zero. Note that this is about Zero: 2, not the first version of Zero (which this topic is supposed to be, I admit).

 

[carlcamper]

Apparently not. Changed the default red eartips to yellow (the biggest available) and the sound changed completely. IMHO they sound pretty balanced now, I don't find bass excessive (but at this point I used them for less than an hour). Also, bass extends pretty deep, it goes much lower compared to TRUTHEAR x Crinacle Zero. Note that this is about Zero: 2, not the first version of Zero (which this topic is supposed to be, I admit).

Same experience, I had to change to foam ear tips, then the bass became excellent

 

[therobin]

I had Blessing 2 for two years as my main IEM. Then when the Truthear Zero Red was reviewed here, I bought a set along with the 7zh Zero. I had all three side by side for about 2 months.

I preferred the sound of the 7zh zero right away but I was having second thoughts about them due the eartip fit. The only eartips that worked for me was the yellow set and didn't feel as secure I would have liked. So I ordered the Spinfit CP145 to replace it (The irony of IEMs so cheap: the third party eartips are 50% the cost of the IEM itself). They are similar in measurement to the stock yellows tips but have a 4.5mm hole felt and felt more secure in my ear. They are much easier to physically fit on on the bore of the IEM as well. After spending those 2 months with them, I sold the Blessing 2 and Zero Red and was happy to keep the 7zh Zero with the spinfits.

Now that I see this review, I am not surprised at all at how well it performs on the bench. This confirms I made the right choice selling and pocketing the cash for the other two. It just a big win-win-win for me. Win for comfort, win for sound and a big win for my wallet even with the cost of the additional eartips (still less than the Zero Reds).

My only complaint now is the cable. I would like it to be a little softer and more flexible. It is also a bit too short for me. The Turthear Zero Red cable was the perfect to me in length and softness/flexibility. Does anyone know if Truthear sell their cable separately or a place to order affordable IEM cables?

 

[IAtaman]

Anyone have experience with the fit of these compared to the Tangzu Wan'er, which has a tiny shell and shallow fit which won't stay in my ears?

I personally like Wan'er better as it fits me fine while I struggle with this Zero. Here are two images to help you compare.

 

[Dunring]

Got a bunch of stuff in, the short summary after trying them all back to back:
7hz X Crinacle Zero thin male vocals, not as good as the others
7hz X Crinacle Zero 2: Excellent vocals and treble, bass is less resolving
ZiiGaat NUO: Best, most detailed bass I've heard in an IEM, male vocals can be a little hot but not shouty.
Truthear Zero Blue: Terrific all around, vocals, piano, violin all great.
Moondrop Chu 2: Female vocals have less presence, least resolving, but much more fun for gaming than expected. Good all around except less impact for vocals. Casual listening fun.

Nuo best for EDM and Hip Hop by a mile.
Zero 2: Hands down the best if low bass detail not your deal breaker.
Truthear Zero Blue: All around performance, can't go wrong.

Out of all of them, I'm keeping the 7hz X Crinacle Zero:2 I don't have that many bass heavy songs, and everything else sounds so good, more resolving than the Zero blue. Going to keep the Ziigaat also, the bass blows everything away with quality and just the right quantity. I wish all headphones and IEMs had bass this good.

 

[ooheadsoo]

My zero 2 arrived today. This is my kind of bass. I usually find that bass “detail” and bass quantity are usually inverse quality due to masking. The zero 2 strikes the right balance for me. I did need to use the yellow tips, as expected from experience.

I like how light the plastic housings are. Alloy iems look nice and feel nice in the hand, but not so great hanging from my ears.

 

[CedarX]

I personally like Wan'er better as it fits me fine while I struggle with this Zero.

Triggered a question…
So we have the Harman target to maximize user FR preference.
For IEMs, is there a similar “shape target” to maximize user fit preference (tradeoff between comfort and “audio-friendly” fit)?

 

[Berwhale]

Triggered a question…
So we have the Harman target to maximize user FR preference.
For IEMs, is there a similar “shape target” to maximize user fit preference (tradeoff between comfort and “audio-friendly” fit)?

I think there is far too much variation in ear structure for a target shape to be useful. I found this paper discussing ear morphology from a forensic science perspective which has some nice illustrations showing just how different we all are... https://ejfs.springeropen.com/articles/10.1186/s41935-019-0111-0

 

[a2Thompson]

It turns out, I do


I looked at it in detail, there are 2 independent variables that affect the preference rating, the std-dev of error curve, and absolute value of the slope of the regression line of the error curve, both of which negatively contribute to preference score.

Looking at the error histograms of both headphones, clearly Stealth has a lot smaller std dev so is the clear winner in that metric. For the absolute slope, HD800S is almost flat while Stealth has slightly larger slope which somehow closes the gap for the std dev score it seems.

When you are training a neural network, it produces these weights and sometimes if the model is small, you expect these weights to have a sense, a meaning of sort. They usually don't yet the model works anyway. This feels like that a bit to me - the deviations from the curve are wildly different but predicted preferences are very similar.

So maybe the preference is not so much about matching the target at every turn. Maybe then it might not be a good idea to look at deviations from the target curve and claim those deviations point to an objectively lower preference? Because, if my understanding is not wrong, it looks like even if a headphone is deviating from the target curve, and doing that in a balanced way that keeps the slope of regression line flat, predicted preference of that headphone might not be very low afterall.

So then the question becomes: what is the actual users preference for either: a lower s.d. of the error curve OR a flatter error regression line? That has probably not been tested.

 

[snackiac]

Figured these were too cheap to not try, and wow they do sound great! Nice fit too, and I have ears that don't fit a lot of IEMs well.

 

[IAtaman]

So then the question becomes: what is the actual users preference for either: a lower s.d. of the error curve OR a flatter error regression line? That has probably not been tested.

Preference rating calculation equation is the result of a regression analysis done on the preference data. The weighting of the std-dev and absolute slope is about equal in the equation that calculates the score.

 

[isostasy]

Triggered a question…
So we have the Harman target to maximize user FR preference.
For IEMs, is there a similar “shape target” to maximize user fit preference (tradeoff between comfort and “audio-friendly” fit)?

I would guess thinner nozzle and smaller body would maximize wide compatibility as this would fit people with small ear canals and people with bigger canals just use bigger tips. Most of the fit complaints I've seen recently on this forum are to do with nozzles being too wide.

I use the Etymotic ER2XR mostly which is tiny (not designed to fit the outer ear at all) with a ~2-3mm nozzle, smaller than any ear canal, so you pick the tips that fit and it won't fall out. Every non-Etymotic earphone I've ever tried doesn't stay sealed in my ear for more than 3 seconds and falls out fully after a few minutes. I think Etymotics could be universally preferred if it weren't for the fact that the deep insertion is uncomfortable for a proportion of people, which becomes a deal breaker rather than a small annoyance.

For me, based on the picture above (thanks @IAtaman ) I'm thinking the Zero could fit better because the nozzle goes off at more of an angle and has a smooth inner face which could allow more adjustment, whilst the Wan'er has that moulded wing which could be pushing it out of my ear.

I'm tempted to save up for the Sennheiser IE200 just because I would like a shallow-insertion IEM and I've heard it fits so well due to being so small, instead of paying the same equivalent amount on trying different cheap IEMs.

 

[CedarX]

I would guess thinner nozzle and smaller body would maximize wide compatibility as this would fit people with small ear canals and people with bigger canals just use bigger tips. Most of the fit complaints I've seen recently on this forum are to do with nozzles being too wide.

I use the Etymotic ER2XR mostly which is tiny (not designed to fit the outer ear at all) with a ~2-3mm nozzle, smaller than any ear canal, so you pick the tips that fit and it won't fall out. Every non-Etymotic earphone I've ever tried doesn't stay sealed in my ear for more than 3 seconds and falls out fully after a few minutes. I think Etymotics could be universally preferred if it weren't for the fact that the deep insertion is uncomfortable for a proportion of people, which becomes a deal breaker rather than a small annoyance.

For me, based on the picture above (thanks @IAtaman ) I'm thinking the Zero could fit better because the nozzle goes off at more of an angle and has a smooth inner face which could allow more adjustment, whilst the Wan'er has that moulded wing which could be pushing it out of my ear.

I'm tempted to save up for the Sennheiser IE200 just because I would like a shallow-insertion IEM and I've heard it fits so well due to being so small, instead of paying the same equivalent amount on trying different cheap IEMs.

I have an ER2SE and ER4XR and like them. I appreciate the isolation and have no problem with the (very!) deep insertion: I read somewhere that by seating very deep they provide a perfect seal and 'some' additional bone conduction effect, which is why their lack of measured bass is less a problem than one could think. But I agree, deep insertion is an absolute no for many! I also have some IEMs where the body just interfere too much with my concha and I can't "forget them"...

I think evaluating the "fit" is as important as the FR for an IEM (less important for a HP in my opinion...)

Should we start a fund for Amir to buy a 3D-scanner and publish a simple 3D model or multi-plans view of each IEM being reviewed?