If you still love Etymotic ER4, this is the thread for you...
May 25, 2019 at 5:30 PM
Isn't a volume knob just a series impedance? That means it adjusts the amplitude of the signal across all frequencies equally. Then simply turning up the volume would compensate for any additional impedance.
hopefully you won't encounter an amp working that way as it would have undesirable and hard to predict consequences. in practice the attenuation will occur somewhere else in the amp design, and in a more stable way than just adding high resistance in series at the output(even a voltage divider would be better). imagine your amp showing 5000ohm at the output after you've set the listening level you want. I wouldn't purchase that amp!

May 25, 2019 at 6:01 PM
Yeah I was wondering about volume changes, I am not sure how volume knobs are calibrated with respecte to the Harman curve. If the volume knob adjusts all frequencies equally, then middle frequencies would overpower lower and higher frequencies (in general) as the volume is increased due to the Harman curve nonlinearity (since the human ear's sensitivity is not equal at all frequencies). This would be very interesting to test as well!

Etymotic and audio in general is one of the reasons I studied EE, even today is is still such a rich topic to make discoveries.
I'm guessing you mean equal loudness contour(the ex Fletcher-Munson curve) instead of Harman curve. a volume knob will attenuate everything equally. well, nothing is perfect, but it's not too hard to get resistors that are mainly just that, so the frequency of the signal won't matter until very high frequencies.
I would personally like a volume knob that makes me feel like the amount of subs and trebles remain fairly stable subjectively at all levels, but to have that we would need to first estimate our own curves as they may differ in some ways compared to human average(or not). and then we would need to know the sensi of the IEM/headphone we're using each time, to calibrate what voltage is equivalent to... maybe a reference of 60dB SPL. so it's pretty impractical but not impossible.

May 26, 2019 at 2:01 AM
So is there anyone who has heard the ER2SE and the ER3SE and could compare? The XRs are all too muddy for me.

May 26, 2019 at 2:03 AM
So is there anyone who has heard the ER2SE and the ER3SE and could compare? The XRs are all too muddy for me.
Get the 2se then.

May 26, 2019 at 2:28 AM
Get the 2se then.
That's not much to go on, do you mean the dynamic driver is clearer than the BA or are you referring to a hypothetical like midtone harmonics? To clarify, I tried the er4xr and returned them for having muddled bass. I have hf3 which I preferred, and er4p before that.

Last edited:
May 26, 2019 at 2:56 AM
Just checked my tracking, my ER2SE has arrived at local post office. Will get it tomorrow, excited

May 26, 2019 at 2:58 AM
That's not much to go on, do you mean the dynamic driver is clearer than the BA or are you referring to a hypothetical like midtone harmonics?
Simply the tuning and frequency response.
Or you can get 3se with PTOS adapter.

May 26, 2019 at 3:08 AM
Would you care to describe the difference between the 3se and the 2se in words? Others were asking as well.

May 26, 2019 at 3:16 AM
Would you care to describe the difference between the 3se and the 2se in words? Others were asking as well.
I don't have er3se but I had er4se er4xr and have er2se, hf5 with and without ptos adapter.
I understand that you are comfortable with flat bass. So basically er2se still has flat bass of all the "s" models. Highs on er2se is more than hf5 stock, and less than er4sr. It's similar to er3se. But er3se has rolled off highs on stock. You need resistor in series to bring up the highs. Otherwise it's similar to hf5 stock. Other than that er2 is dynamic driver and according to measurements it has much lower distortion especially at normal listening volume. With low output impedance amplifier it sounds clean transparent and smooth, er4 will sound in comparison a little dirty in the highs.

Summing it up.
Stock: er2se has more highs than er3se.
If er3se has resistor adapter like ptos, er3se will have more highs and less lows.

May 26, 2019 at 3:34 AM
I don't have er3se but I had er4se er4xr and have er2se, hf5 with and without ptos adapter.
I understand that you are comfortable with flat bass. So basically er2se still has flat bass of all the "s" models. Highs on er2se is more than hf5 stock, and less than er4sr. It's similar to er3se. But er3se has rolled off highs on stock. You need resistor in series to bring up the highs. Otherwise it's similar to hf5 stock. Other than that er2 is dynamic driver and according to measurements it has much lower distortion especially at normal listening volume. With low output impedance amplifier it sounds clean transparent and smooth, er4 will sound in comparison a little dirty in the highs.

Summing it up.
Stock: er2se has more highs than er3se.
If er3se has resistor adapter like ptos, er3se will have more highs and less lows.

So you don't currently have the er4se or er4xr anymore? I'm asking because it's really hard to compare from memory. If you still have them then I have a few questions to ask you. Bass wise between the Er3se vs er2se, which is tighter/better? What about highs? Which has cleaner highs. No I'm not asking which has more of it.

Last edited:
May 26, 2019 at 3:39 AM
So you don't currently have the er4se or er4xr anymore? I'm asking because it's really hard to compare from memory. If you still have them then I would like to ask you this question. Bass wise between the Er3se vs er2se, which is tighter/better? What about highs?
I had compared hf5 + ptos adapter to er4sr. They are really really close. Also I said above mostly according to measurements. So it's objective and consistent. Hf5 + ptos/er4sr is brighter than er2se. Er3se is less bright than hf5 + ptos/er4sr. er3se is similar to er4p/hf5
er2se has more top end than er3se but somehow less 4-6khz. But er2se just sounds well rounded and complete.
er3se + ptos will be very similar or probably little brighter than er4sr, which is brighter than er2se.

May 26, 2019 at 3:47 AM
SIMPLY
BASS ER2SE is better extended and more dynamic.
HIGHS ER2SE is cleaner and more extented than ER3SE stock

May 26, 2019 at 7:37 AM
SIMPLY
BASS ER2SE is better extended and more dynamic.
HIGHS ER2SE is cleaner and more extented than ER3SE stock
I had compared hf5 + ptos adapter to er4sr. They are really really close. Also I said above mostly according to measurements. So it's objective and consistent. Hf5 + ptos/er4sr is brighter than er2se. Er3se is less bright than hf5 + ptos/er4sr. er3se is similar to er4p/hf5
er2se has more top end than er3se but somehow less 4-6khz. But er2se just sounds well rounded and complete.
er3se + ptos will be very similar or probably little brighter than er4sr, which is brighter than er2se.
I am confused by the adapters. I have a Er3se with adapter but was thinking of trying the Er4sr. Is this a waste of money? Is the difference between the two only in treble measurement and the Er4sr is not more refined or cleaner or has a better quality in some way? I am asking about a quality other than measurement. What would I hear differently between the Er3se/adapter and Er4sr?

Last edited:
May 26, 2019 at 7:48 AM
I am asking about a quality other than measurement. What would I hear differently between the Er3se/adapter and Er4sr?

If we were able to precisely tell a person the immeasurable difference between any headphones, that would be amazing.

May 26, 2019 at 8:29 AM
I just ordered the ER2XR on Amazon. According to them it will be here in 1-2 days. I will try that against the ER2SR and the ER4XR shortly and relate my own views/comparison.