Color accuracy measurement is absolute, which is the delta between actual vs expected.

The issue with audio frequency response is the target. There is no standard on what is the correct or right target. And different folks can have varying preference on the target. Should it be Harman (and there are multiple Harman targets), IEF, Diffused Field, etc? So calculating the deviation from a moving goalpost is difficult.

If you like fancy 3 D plots, there are CSD (Cum Spectral Delay) measurements with frequency and impulse. Looks cool. Here is an example from HD600, on SBAF forum.

https://www.superbestaudiofriends.org/index.php?threads/sennheiser-hd600-measurements-2019.7499/#post-247043

However, my personal take is that measurements are not very useful, for both headphones and amps. At first level, frequency measurements can be used to filter out headphones (v-shaped, neutral, bass boost, hot treble). But I can get that info from reviews easily. And then on the headphone technical performance, measurements do not tell me about soundstage, imaging, separation, layering, and dynamics (maybe CSD).

As for amp, SNR (SINAD) and THD are also kind of useless. They measure minute differences, which human cannot hear or detect. On the other hand, tube amps measure like crap, but sometimes (or often) they provide more enjoyable listening experience than the best measuring solid state amps.

Not sure what you are reading. That was exactly my statement: "Sony (consumer grade)".

I cannot comment on S2, since I haven't heard it.

However, Beats and Sony (consumer grade) headphones do not have good reputation and are not known as good match for audiophile sound. So associating S2 with Beats and Sony is not a compliment.

Define better?

For me, foam has better isolation. But foam expands and put a lot of pressure in the ear canal. So silicone is much more comfortable. I prefer silicone as comfort is more important to me.

Answer 1: No one would know what you will think. You can wait 1 more day and let us know.

Answer 2: HD560S needs 9 mW to support peaks/transients of 110 dB, 27 mW to 115 dB. Not difficult to meet. But will be marginal for dongle. Dongles typically don't list detailed specs. Apple dongle output 31 mW at 32 ohm; 3.6 mW at 300 ohm. It is around that 9mW at 150 ohm; it will not meet 27 mW at 150 ohm. So it will depend on how loud you listen and what type of music/recording (and dynamic range in the recording).

Also, if you care about audio quality, $10 dongles (including Apple dongle) do not sound as good, compared to better dongles and desktop setup.

Get a cat. The cat will teach your son how to do it right. One try, one bite, the cable should be permanently damaged.

Thanks for the correction. So I went ahead and looked up HD600 spec: https://www.sennheiser-hearing.com/en-US/p/hd-600/

• 97 dB/V sensitivity (not the 104 dB/V as stated by previous poster)
• 300 ohm impedance
• It requires 22 mW or 2.6V to reach 105 dB SPL.
• It requires 67 mW or 4.5V to reach 110 dB SPL.
• Etc

Apple dongle is 3.6mW or 1V at 300 ohm. No, Apple dongle is not sufficient, for most people listening to 75-80 dB with 30 dB dynamic range.

I believe Hifiman QC issue rate is higher than typical. But they are likely still low. Most likely it is less than a handful per hundred. No one knows for sure.

If you think Sundara is so great, then do RMA. Or return and buy another; that way you can always return again if you encounter another issue.

On the other hand, if you can get similar value and sound in another brand/model, go for that. You have better peace of mind.

I agree with you. There are so many misconception and just flat out wrong info, floating around on this forum.

Audiosciencereview measured Apple dongle and found that it has good SNR and THD. SNR and THD can be measured. But there are other even more critical factors, like how the device sounds.

People claim DAC and Amp are (or should be) transparent. So that every DAC and Amp should sound the same. Apple dongle is as good as any other DAC/Amp.

Look, Apple dongle is $9. If someone needs a dongle for their phone, just get it. But don't BS that this dongle is a great replacement for $100 entry level desktop DAC/Amp.

Every DAC and Amp I have tried sound different. Most are so close that I cannot say which is better or worse, just different. Apple dongle is no comparison vs >$30 dongles and also desktop DAC/Amp. Thin, lacks dynamics, less punchy, muted treble, less open/airy. And it lacks power. It is measured to have 31 mW at 32 ohms and 3.6 mW at 300 ohm. Not sufficient for some headphones, like Hifiman's Sundara. Not enough volume even at 100% volume; and sound is compressed (because it is clipping).

(Edit: Based on follow-up post below, updated calculations based on actual sensitivity and corrected for dB/V)

So I went ahead and looked up HD600 spec: https://www.sennheiser-hearing.com/en-US/p/hd-600/

• 97 dB/V sensitivity (not the 104 dB/V as stated by previous poster)
• 300 ohm impedance
• 1mW or 0.55mV to reach 85 dB SPL
• 3mW or 1V to reach 96 dB SPL

So your numbers do not the spec of the headphones.

In any case, the comment below doesn't change. Assuming your setup can output 85 dB peak, then if you listen to average SPL of 55 dB SPL or less, and assume the dynamic range in your music is 30 dB. Then you are good. Your peaks will only reach 85 dB SPL.

On the other hand, if you are at 65 dB SPL average, with 30dB dynamic range in your source, then your peaks should be at 95 dB SPL. And if your device can drive to 85 dB, then some of the peaks will be clipped. It can be hard to tell when music is slightly clipped. Like 90-95% of the sound is there. It will sound slightly compressed (less dynamic) because the max levels are cut off.

95% of the headphones have no issue with power with most amps. So people will say power is BS and there is no such thing as lack of power. But there are outliers. Some people listen to loud music. Some music recordings have high dynamics. And some headphones do require Watts of power (e.g. Susvara, HE6se).

Don't confuse average with peak. There are easily 20-30 dB of dynamic range in the music. And can be more for audiophile recordings. If you are listening to peak SPL 75dB, then your average SPL is like 45dB, which is very unlikely.

Most people are listening to 65-85 dB average, with peak SPL reaching 105-115 dB. That is why power calculators defaults at 110dB.

https://www.audeze.com/blogs/technology-and-innovation/sensitivity-impedance-and-amplifier-power

https://nwavguy.blogspot.com/2011/09/more-power.html

No, Apple dongle is not sufficient. 97 dB at 300 ohm requires 20mW to reach 110 dB SPL (for peaks and transients), or 7mW to 105 dB SPL (in the very best case where someone listen to low volume and compressed music).

Apple dongle is measured to be 3.6 mW at 300 ohm. This is 2x short for 105 dB and 5x short at 110 dB.

EQ is to fix the tonality to your preference.

Oratory EQ is drive toward Harman target. Maybe Harman target is not your liking.

However, to say no EQ is always the best is not valid argument either. All your headphones have different tonality. So you cannot say every single one has perfect tonality.

There are quite a bit of discussions online regarding 660S and 700 drivers. Some say 660S is based on 700, but that doesn't mean it is the same driver. Others made measurements and say they have similar impedance and phase response, but then they don't sound alike at all.

https://www.stereophile.com/content/sennheiser-hd-660-s-over-ear-open-headphones

I guess at end of the day, it is how they sound that matters, regardless of their driver design. Let us know your verdict when you have thoroughly compared them.

Larger numbers always better. Just like computer CPU megahertz (or gigahertz). And camera megapixels. Everyone needs that 108 megapixel camera in cellphone to take photos to post on Instagram to be viewed on small phone screen.

Is that APM (Apple Airpods Max) in the background? Blasphemy. Putting that in the same photo as HD660S. Just joking.

I'm listening to my HD660S right now. I normally listen to Alternative and Pop. Right now, listening to this Egyptian Electro-Shaabi or Mahraganat song It is in Arabic, so I don't understand it. The bass really comes thru on HD660S.

https://www.youtube.com/watch?v=I_nvzVDZVWI

Nice, look like art pieces in a museum.

If you want large soundstage, but ok with lean mids and recessed vocals. Try Hifiman Sundara and Edition Xs.

If you want forward vocals, excellent imaging and separation, but ok with smaller soundstage, then try HD660s. Note that imaging and separation are related, but those are not the same as soundatage.

I don’t have motion sickness. I do feel the cabin pressure of ANC headphones. I stopped using ANC 20 years ago. I use IEM when I need to block out sound. And I have Apple AirPods Pro and Shure Aonic with ANC, but I don’t use ANC fearure.

I believe your headphones do not have removable cables. You can buy extension cable cheaply. That would be my suggestion.

For DT 770 Pro, I would not spend money on dac/amp. Unless you think dac/amp can be used in near future when you upgrade headphones.

Op, I believe you enjoy the open soundstage of HE6se V2. Newer Hifimans have more open and larger soundstage. If you really like soundstage, you should try those out.

It is a balance between presence and soundstage. Some headphones like Sennheiser HD6x0 series have forward and present mids/vocals, but small soundstage. Other headphones like newer Hifimans have open and soundstage, but mids/vocals sound lean and recessed.

HE6se V2 is in between. It's vocals are reasonably forward, and soundstage is also average. Nothing wrong with that. Good balance for forwardness and soundstage.

And bass is just separate attribute that really stand out on HE6se V2. Punchy and impactful.

Not all velour is same. Sennheiser velour has short felt and light. I like it. I have tried other velour on Beyer DT700 Pro. Very thick and heavy. Hot and sweaty.

Grats!

Any reason you got 400 Pro over 560S? They are sonically the same. Different logo and cables.

I don't have Drop THX AAA 789. I do have its little single-ended brother Drop THX AAA One. Still under warranty. Fingers crossed it will continue to work well.

Here is my take. The issue is entire consumer market. Most consumers buy products for value (cheaper the better). Besides a small minority, most are not willing to pay more for quality.

The result is that manufacturers and merchant just focus on building the cheapest product. $250-$300 for THX AAA 789 was a greate deal. I am sure there wereshort cuts. Such as using cheaper components, reduced quality control, reduced testing, etc. And result is likely slightly higher failure rate. Hard to say what that failure rate is. Is it 1/100, 1/1000, etc?

And there is no guarantee that cheap product will fail prematurely. Or high-end premium product won't fail. So on average, most consumer still wins with the value products.

Cool, enjoy your Sundara.

Great soundstage. Good imaging/separation.

But sound is dry and analytical. And vocals is just passable and recessed. I had Sundara for close to 1 year. Then upgraded.