Matching low frequency response on both channels
Jan 19, 2020 at 5:42 PM Thread Starter Post #1 of 50

carmatic

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Hello people, this has been something which has been bothering me ever since I have started using personal music systems many years ago

I like to listen to bass-heavy music, and I find it extremely uncomfortable when I can hear that one of the channels gives out more bass than the other, it is a slightly nauseating experience... For instance, on my current pair of Etymotic ER3XR's , I have managed to detect it with a desktop mic: https://www.head-fi.org/threads/if-...-thread-for-you.538615/page-932#post-15121217 , and for sure it is not a problem with my own hearing... I used to own ER-4 earphones which come with Etymotic's matching, but the matching only goes down to 100hz, and I have had similar bass mismatch experiences with those

Are there headphones or earphones out there which match down into the bass region? Or is this a problem which it seems only I am bothered about?
 
Jan 20, 2020 at 1:33 AM Post #2 of 50
I've never experienced a bass mismatch that didn't relate to the degree of seal for either a closed headphone or IEM. IEMs in particular really must seal very well in the ear canal or bass just vanishes. I do mess with IEMs to get the seal right, sometimes it works better than others. But when both ears fully seal, I've never noticed a mismatch, even with much cheaper units.

If it's really a problem with one channel, you should be able to swap hearphones/ears and the problem will follow the earphone.
 
Jan 20, 2020 at 2:36 AM Post #3 of 50
If it's really a problem with one channel, you should be able to swap hearphones/ears and the problem will follow the earphone.
thats the advantage of the Etymotic ER series , the drivers are symmetrical and detachable so you could swap the drivers around... thats how I became aware that it's not a problem with my own hearing
but I have since started using a software, Room Equalizer Wizard, which does frequency sweeps and records the response from a mic, and I could get the mismatch on my current pair of ER3 IEM's on a graph... as long as the eartip can fit on the micrphone, I could do the same test on any other IEM, but the biggest variable is how the insertion of the earpiece affects the transmission of sound, I will have to take the average of many readings over many insertions to get a clean result
 
Jan 20, 2020 at 9:54 AM Post #4 of 50
I EQed one channel to get an imbalance similar to what you measured and not only does it not bother me, I have a real hard time telling it's there. What I notice is how the level changes when I switch the EQ ON and OFF. But I don't notice the imbalance by itself on any music I tried(did it with ER4SR and IE80 set to max bass).
As you noticed doing measurements, you can expect that many people will create their own imbalance with the way they insert their IEMs. Yet, few people really bother going beyond finding comfort and a reasonable seal. That should tell you how atypical your reaction is.

About finding IEMs with great matching, I'm afraid that for something that small at such a low frequency, you'll have to rely on luck. It's probably not in the QC list of any manufacturer. I have a few IEMs with good looking low end match, but those just have imbalance somewhere else:slight_frown:.
 
Jan 20, 2020 at 10:24 AM Post #5 of 50
thats the advantage of the Etymotic ER series , the drivers are symmetrical and detachable so you could swap the drivers around... thats how I became aware that it's not a problem with my own hearing
but I have since started using a software, Room Equalizer Wizard, which does frequency sweeps and records the response from a mic, and I could get the mismatch on my current pair of ER3 IEM's on a graph... as long as the eartip can fit on the micrphone, I could do the same test on any other IEM, but the biggest variable is how the insertion of the earpiece affects the transmission of sound, I will have to take the average of many readings over many insertions to get a clean result
What did Etymotic Support say when you contacted them about this?
 
Jan 20, 2020 at 10:40 AM Post #6 of 50
Ety's matching is like +/-1dB from 100Hz to 10Khz for the ER4 series. I think the rest doesn't even have that tight a channel matching requirement.
 
Jan 20, 2020 at 10:46 AM Post #7 of 50
Ety's matching is like +/-1dB from 100Hz to 10Khz for the ER4 series. I think the rest doesn't even have that tight a channel matching requirement.
Well, their FR spec is nonsense to begin with (FR with no tolerance is meaningless). But if it's really that bad I'd be in their face first, then looking for better phones second. I have little experience with Ety, but what I do have was not impressive. Every time I look at their models I can't find one I'd buy for one reason or another.
 
Jul 31, 2020 at 1:58 AM Post #8 of 50
I am pretty sure that it's not my own hearing that's at fault because I've bought another pair of detachable IEM's , the Audio Technica ATH-E70 , they have a more complex shape but they still fit just as well both ways, and the bass is lacking on the right channel earpiece

Needless to say, I'm in the market for another pair of IEM's , but I'm not spending any money until I can find a pair which is guaranteed to match down into the low frequencies
 
Jul 31, 2020 at 2:20 AM Post #9 of 50
What did Etymotic Support say when you contacted them about this?
the response has always been the same, that there is no defect , which technically is correct according to their matching standards which doesn't cover below 100hz
 
Aug 3, 2020 at 11:56 AM Post #10 of 50
so I was in the shop just now and I saw a pair of JH Audio IEM's , they have a bass adjustment knob on each side... could this be the solution?
 
Aug 3, 2020 at 12:52 PM Post #11 of 50
Manufacturing tolerances on headphones are usually around +/-3dB. But I would imagine better manufacturers at least try to match the left and right in a single set. I'd bet you got stuck with a set near the outside of their tolerances. If I'm reading your measurement right, the difference is 2dB. That isn't a lot. I think it's highly unlikely that the right side is always lower, even with different manufacturers and models.
 
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Aug 3, 2020 at 3:48 PM Post #12 of 50
Manufacturing tolerances on headphones are usually around +/-3dB. But I would imagine better manufacturers at least try to match the left and right in a single set. I'd bet you got stuck with a set near the outside of their tolerances. If I'm reading your measurement right, the difference is 2dB. That isn't a lot. I think it's highly unlikely that the right side is always lower, even with different manufacturers and models.
Thanks for your reply, in this case the sample size was only 2 and the odds are 50/50 that it's the right hand side again, besides the Etymotic drivers are not side-specific, it just which end of the cable the drivers happen to be attached to when they were being packed

I find it very confusing that I seem to be the only person in the world who is bothered by low frequency mismatch between drivers, surely I can't be the only one who has a problem? My stopgap measure so far, as long as I am on my Windows computer, is to install Equalizer APO to digitally reduce the 30-60 hz region on one channel by ~1.5 dB but it's never going to be perfect as long as I do it by ear
 
Aug 3, 2020 at 4:12 PM Post #13 of 50
I think people don’t think it’s a big deal because it’s a very small imbalance in a narrow range. Under most music, it would be inaudible. You must listen to bass heavy music. It could be that one driver handles bass better than the other, not that one is attenuated.
 
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Aug 3, 2020 at 9:21 PM Post #14 of 50
Are there headphones or earphones out there which match down into the bass region? Or is this a problem which it seems only I am bothered about?
If you want to be sure about your next purchases, using measurements to compare channel balance is a good measure to know what are you getting into.
 
Aug 3, 2020 at 9:23 PM Post #15 of 50
The problem is that the difference he is talking about is less than the manufacturing tolerances of mid range cans. He could find a model he likes, but the copy he ends up with might be slightly off. I think the only solution is to buy somewhere that you can return them for exchange until you find a set that is "just right". It's like the Princess and the Pea.
 

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