Oh my goodness it’s true! I mistyped it! It is 70db and you were right my bad. Yeah I could imagine at low levels THD+N could be high then. I am sorry, I was thrown off by the tone rather than content

Legitimately, thank you for helping me better understand real world listening level distortion.

Edit: I am wrong! See below

here’s a calculator, let’s try. https://reference-audio-analyzer.pro/en/splfull.php#gsc.tab=0

Enter 100db/mW sensitivity, 300ohm, and 0.0001 mW load on amp gives 60db. 66db at 4microwatt, 72db at 16microwatt. By 70db, the THD+N of the apple dongle is audible transparent. If you’re listening less than that and can pick up noise over background sounds on your open back hd650s, then you can surely justify spending more than $9 on an amp.

Remember we’re talking about THD+N of 0.05% which is 66db below the fundamental measured. You’re not gonna hear that at 70db signal with open back headphones.

It’s a ~6db change for double output power (as I hope you found by using the calculator!) 10db is a doubling of perceived volume. Please read the link, I think it would bridge this gap. Instead, you assumed that I don’t understand logs lol. This won’t go much further, but I do encourage you to at least read it. Fun talking with you.

https://physics.stackexchange.com/questions/366774/twice-the-audio-source-3-6-or-10-db-spl

Not once did I mention mV. I haven’t confused them. Double the spl is 6db additional. You might be confused about perceived volume vs power.

Aha I did misunderstand. Going from the spec of 100db at 1mW, it would be 52db at 15microwatts. I still think that’s acceptable, maybe you don’t. Certainly on the threshold of audibility and at low spl.

Correct it please. I got the 30db from your post, you said you often listen at those levels. If you listen higher, it uses much more power and we’re back to being far away from audibility of THD+N.

Hearing is significantly less discerning at low SPL. If you’re listening at 30db on open back headphones, I promise you will not notice 0.05% THD+N. In fact, I’d imagine it’s starting to get hard to hear the signal at 30db over the environmental noise. The room I’m in currently is 45db of background sound.

If 1microwatt is 30db, 16microwatts would be 42db, and still below the audibility threshold of THD+N, and your signal is still likely lower than environmental sounds so THD+N is likely not top of mind.

Lastly, your baseless condescension isn’t appreciated

Edit: typo, thanks for pointing it out in a non condescending way /s

And in those edge cases where you can audibly hear the distortion and noise, it would be worth getting a lower noise source. For all other cases it doesn’t matter

The effects of the device are measurable, and it is calculable if the device will provide a sufficiently low distortion signal. Nobody is listening to music on a hd600 at 10µW, yet there’s endless, baseless discussion in this thread of how much (immeasurably) better their not-ultra-high-sensitive headphones are sounding from whatever amp.

The apple dongle’s THD+N at 10 μW into 33ohm is at or below the audibility threshold.

https://www.audiosciencereview.com/forum/index.php?threads/review-apple-vs-google-usb-c-headphone-adapters.5541/

Wow that sounds interesting! I would like to know the size of the effect. Are there frequency response and distortion graphs of the 770 with the apple dongle and with the element 3 (or literally any other headphones with an apple dongle vs anything else)?