Spuriae

For an effective comparison, you would need to find a recording of your headphones and compare them to a recording of the other headphones. A comparison with listening on your headphones directly only works if you listen to the other headphones directly too. Keep in mind this still isn't a perfect comparison - for instance, if your headphones have less treble than usual, they could make a recording of a headphone with too much treble sound unnaturally good - but it's much better than working off a single recording alone.

The sound of any headphone (including an IEM) is partially determined by the way the wearer's body acoustically interacts with the device, and is not purely a function of the device itself. This is why frequency response curves for the same headphone taken from different test rigs often look different. This means not only that the recording from a microphone can vary from what you hear, but that different people (with different ear structures) will often hear different things from the same headphones. For instance check out this measurement from Harman comparing headphone frequency responses on different people and test microphones: Similarly, Crinacle has a good piece on how IEM sound is affected by the listener's ear canal: https://crinacle.com/2020/04/08/graphs-101-how-to-read-headphone-measurements/ (and that's with a standardized inner ear simulator; real humans will vary even more!). Another factor: in the video, the IEM is mounted to what appears to be an IEC60318 inner ear simulator rather than directly to a microphone. This simulator is designed to mimic the frequency response of a human ear for more accurate measurements at the "eardrum" microphone; however, if you're listening to the recording on headphones, your actual ear will also have this response... in effect, the recording playback as perceived by the listener will contain the ear resonance twice, which affects the treble in large and unpredictable ways. In other words, the listening demo is a good way to compare headphones, but not a good way to know in absolute terms how a headphone sounds. For instance, if you listen to a demo of a headphone you're familiar with, it shouldn't sound like it does in real life, but you can it as a reference point to better determine how a headphone you haven't listened to yet might sound, relative to that familiar headphone.

Are you looking for a headset or just the headphones? Will this be for gaming, on the go, etc.? Does it need to be closed-back, or is open back an option? Not knowing much about your use case, consider the HyperX Clouds for $35, which are probably the best all-around conventional closed-backs at the $35 price point. The Koss offerings that @Skipple mentioned (and the similar KSC75 ear hook from the same family) are probably the best-sounding headphones within your budget, but if you don't have any other headphones I think the quality of life/durability/comfort advantage on the Clouds is worth the tradeoff in sound quality.

Open backs are roughly as loud on the outside as closed-back headphones taken off your head and rotated to have the cups facing outwards. You can try that with your current headphones to get an idea of whether it's too much sound leakage. FWIW I've had roommates with open backs and it has never been an issue.

Small (e.g. wristband-sized) wearable tactile transducers exist and do work, so it definitely doesn't need to be a whole body thing. I was curious if the limitation was the headphone's poor coupling to the skin or a loudness limitation, so I tried again with the HE400SE at 15Hz (and with earplugs in). At 600mW input, the headphones started to perceptibly vibrate, with the 15Hz tone somewhat audible through the earplugs. At 2.5W input (any higher caused scary-sounding clipping noises), the headphones were vibrating in an appreciable bass-enhancing way. I could somewhat feel puffs of air coming off the drivers, but most of the effect was vibrations in the housing coming through the pads. The 15Hz tone was also very much audible through the earplugs, so easily hearing damage territory without the earplugs. Feeling tactile bass with normal headphones is possible, but not under any reasonable listening conditions, and is also a bad idea.

I was skeptical, so I tested it. After all, tactile transducers exist; why can't the same effect be obtained in normal headphones, right? You're absolutely correct. I was wrong. There is no meaningful haptic effect. Even with the drivers full-on physically clipping I felt nothing tactile. While I was able to hear below 20Hz as a distinct tone, it would probably never be audible with other sounds playing at the same time.

A frequency response spec given only as a range between two frequencies is completely meaningless, since you can technically produce any range of frequencies with almost any device – it's the loudness at that frequency that really matters. For instance, Airpods can technically produce bass down to 20Hz, but bass they produce at 20Hz is too quiet to be meaningful. It wouldn't be a lie to spec their lower range to 20Hz, or 5Hz, or whatever arbitrarily high or low number; it just wouldn't tell you anything about how they sound. Being able to produce frequencies beyond the conventional audible range has some benefits; you can feel lower frequency as haptics and can perceive higher frequencies are improved timing accuracy. Practically speaking, however, it's rare for these qualities to be relevant or even audible in everyday music listening, given how many other factors have a greater effect.

Most motherboards actually output the most power at around 80Ω due to a 75Ω output resistor. Impedance as almost no correlation with difficulty to drive in practice, and efficiency/sensitivity is the spec that really matters. In general motherboards can get most headphones loud enough, but the sound quality will be reduced due to the motherboard's high output impedance.

How are you measuring the impedance? Impedance should vary based on frequency. If you're doing a resistance measurement, the capacitor acts like an open circuit with a DC input so you're essentially measuring the resistance of the wire in the woofer. 6Ω (resistance) on an 8Ω (nominal impedance) woofer is normal.

Crinacle ranks the SRH840A above the LCD2C. Rather than being 4x as good in general, it's more accurate to say that most of the differences above ~$200 tier are more a matter of different preferences and tradeoffs than strictly being better. For what it's worth, if I could only own one and they were the same price, I'd rather have the HD600 than the LCD2C. The LCD2C is better in some ways and worse in others, and I value the HD600's advantages more. You may feel differently, and that's entirely valid. If anything, it's a good reminder that trying out headphones in person before making a purchasing decision is the best approach, whenever practical.

Rereading the first post, I don't think they have actually listened with the Dawn Pro yet, and are only comparing the motherboard and phone to the Chord Mojo. I wonder if louder listening levels and different comparison headphones being available in-store compared to the home environment is also contributing to the higher perceived bass. This is true for amplifiers which clip, but the motherboard doesn't clip. If OP is fine with the motherboard below 50% volume, the output is limited by the digital volume setting and they genuinely have enough headroom for their content. For amplifiers that don't clip, the main takeaway is the need for additional volume headroom – that derating from the peak to the average loudness is necessary. Even then, the peak levels they mention are misleading – virtually all commercially popular music has less than 15dB difference between peak and RMS level. The example used in the article (Black Arthur's Bounce) is an outlier and even then "only" has a -25dBfs RMS level. Personally, I usually use 15dB derating as a rule of thumb for "loud enough", and like to leave an extra 15dB headroom for EQ. Clipping a driver from too much power can certainly damage it, but how does limiting the driver's power via signal clipping damage it?

To be fair the 2018 Sundara isn't supposed to have more bass than the HD560S. Power-wise, here's an approximate comparison: Source V into 32Ω (Vrms) Power into 40Ω, at 32Ω voltage (mW) Sundara max SPL (dBSPL) FiiO KA3 SE 2.05 113.6 110.5 FiiO KA3 Balanced 2.75 204.4 113.1 Moondrop Dawn 3.5mm 1.6 69.2 108.4 Moondrop Dawn 4.4mm 2.1 119.2 110.7 Generic ALC1220 Motherboard 0.6 9.7 99.9 LG V50 Quad ES9218P 0.34 3.1 94.9 Sensitivity/Impedance measurements for Sundara taken from ASR. KA3 measurements from 7AudioLab. Moondrop Dawn measurements from 7AudioLab. There should be no difference between the output power of the standalone 3.5mm and 4.4mm versions of the Dawn and the combined Dawn Pro, because they use basically the same output circuit. This is supported by the 4.4mm Dawn's measured output power almost perfectly matching the spec on the Dawn Pro. ALC1220 Motherboard numbers based on Realtek datasheet. The ALC1220 and ALC4080 are interchangeable power-wise since they should share the same analog section. LG V50 based on my own measurements just now. They are close to ASR's measurements of the G7.

The vast majority of desktop motherboards have 75Ω outputs, so they actually deliver slightly more power into 80Ω than into 32Ω, all else being equal.

Normally your use case would be ripe for something like the M50X wireless or K371 wireless, since those are meant to be studio headphones with added bluetooth. But in this particular circumstance I'd probably go with a Bose QC35, if the market for those is reasonable where you are. The XM3/XM4/QC45 are also good options. There are a couple of factors here that favor ANC headphones: Isolation is useful Long hair is likely to breach the headphones' seal which completely changes the bass response of closed-back headphones; feedback ANC microphones correct for this effect Latency isn't an issue The downsides of ANC still remain: Worse mid and treble timbre (but not necessarily wideband frequency response) due to imperfect correction signals Possible "cabin pressure" discomfort depending on the person Poor perceived soundstage due to internal microphones "correcting" the listener's pinna response Only sound good with ANC on I think the QC35 is a slightly better fit than the other consumer ANC headphones because: It is close to Harman neutral, with the exception of grainy high treble above ~7kHz The bass correction on the Sonys is underdamped, which means they have more rolloff and unexpected midbass peaking if the seal is compromised (though still not as bad as most passive closed-backs) At least in the US, the Bose models are cheaper Better controls (IMO) The Sony models still have a couple of upsides worth considering: For most people the Bose is more comfortable due to the reduced clamp force, but the higher clamp force on the Sonys may be a positive for someone with a small head if too little clamp force is an issue with other headphones More consistent high treble, though the bass is boosted and the mids are subdued compared to neutral (though not extreme by any means) Weaker at the hinges but otherwise difficult to damage in a cosmetically obvious way, whereas the Bose metal cups are prone to purely cosmetic denting Better-looking (IMO) Overall, I don't think any of the headphones listed above are bad choices, and it really comes down to weighing the benefits of each vs your local pricing.

Which studio headphones are you looking to match the sound of, or are you more interested in a certain neutral reference curve? Are ANC, latency, or passive isolation important? Will she be wearing the headphones over long hair and/or glasses?