[NineRedTools]

I'm using my DT770s, using Audacity, generating low-frequency tones from 20-50Hz. Turning the volume up to where the bass actually at a normal volume, it starts to produce a harsh clipping, rattling sound. These DT770s did this from when I first bought them brand new, on both sides (although, more-so on the left cup). So, how loud do headphones actually handle bass? I've never learned how loud bass should actually be. I'm not much of a basshead, but when listening to music with bass at louder volumes, it's hard to without EQing the bass down as it causes the bass to clip.
 
I'm using these headphones with a Schiit Magni 2 amp.

 

[ProtegeManiac]

  I'm using my DT770s, using Audacity, generating low-frequency tones from 20-50Hz. Turning the volume up to where the bass actually at a normal volume, it starts to produce a harsh clipping, rattling sound. These DT770s did this from when I first bought them brand new, on both sides (although, more-so on the left cup). So, how loud do headphones actually handle bass? I've never learned how loud bass should actually be. I'm not much of a basshead, but when listening to music with bass at louder volumes, it's hard to without EQing the bass down as it causes the bass to clip.
 
I'm using these headphones with a Schiit Magni 2 amp.

 

Normally clipping and distortion would partly be due to the amp, but given the Magni2, we can set that aside for now save for extreme situations.

 

The other half of that is the headphone (or speaker), whether  the driver or the enclosure. I'm much more familiar with speakers, and those are easier examples actually. Most speakers use ported enclosures, and the dimensions of the box can affect both response and dampening. Design a box too large with a port too aggressive for the drivers, and the box would hardly dampen the speaker excursion, with the port boosting the bass as well and making it worse.

 

As for the DT770, most of the bass boost AFAIK can be attributed to the sealed cup and partly to the earpads, and theoretically dampens the driver better (it's more of the isolation and the bass not leaking out that boosts the response). Bass clipping usually sounds more of a "thwack!!!" sound that feels like a finger flick on your eardrums, not necessarily rattling, which usually happens when the driver is out of control (see YouTube vids of cars with bass systems; mic on smartphones they use don't pick up the actual freqs but they show the sub and there are still audible clues to suggest when that is already happening). If that isn't the same sort of rattling it's possible the drivers aren't mounted properly; with open headphones the usual culprit is debris like hair, not anything in terms of THD.

 

[NineRedTools]

Normally clipping and distortion would partly be due to the amp, but given the Magni2, we can set that aside for now save for extreme situations.

The other half of that is the headphone (or speaker), whether  the driver or the enclosure. I'm much more familiar with speakers, and those are easier examples actually. Most speakers use ported enclosures, and the dimensions of the box can affect both response and dampening. Design a box too large with a port too aggressive for the drivers, and the box would hardly dampen the speaker excursion, with the port boosting the bass as well and making it worse.

As for the DT770, most of the bass boost AFAIK can be attributed to the sealed cup and partly to the earpads, and theoretically dampens the driver better (it's more of the isolation and the bass not leaking out that boosts the response). Bass clipping usually sounds more of a "thwack!!!" sound that feels like a finger flick on your eardrums, not necessarily rattling, which usually happens when the driver is out of control (see YouTube vids of cars with bass systems; mic on smartphones they use don't pick up the actual freqs but they show the sub and there are still audible clues to suggest when that is already happening). If that isn't the same sort of rattling it's possible the drivers aren't mounted properly; with open headphones the usual culprit is debris like hair, not anything in terms of THD.

The best way I can describe the sound is it sounds like a loud motorcycle or lawnmower engine in a way. Not the "Vrrrrr" noise, but more of a popping sound. The best way I can write the sound is like "TAKTAKTAKTAK". It's 'taks' at a rate of like 5-10 times a second

 

[billybob_jcv]

If you were to listen to a tone at 2000 Hz at the same volume that you hear the problem at 30 Hz, how loud would the 2000 Hz tone be? Is it so loud that it is painful? What about 10K Hz?

Humans do not perceive all frequencies at the same level. There is a concept called the "equal loudness contour" that maps the average human perception at different frequencies.




What this graph says is that in order for a human to perceive a ~40 dB SPL tone at 2000 Hz with the same loudness at 20 Hz, the 20 Hz tone has to be at ~100 dB. That's a huge difference.

This is why trying to measure frequency response by ear is a complete waste of time. You really need to do it the way reviewers like Tyll do it - using an instrumented & mic'd head in an anechoic chamber.

It would not surprise me if you are driving the headphones into distortion by trying to get a pure 20 Hz tone to the same level as a 2000 Hz tone. I just hope you haven't already damaged your drivers.

 

[NineRedTools]

If you were to listen to a tone at 2000 Hz at the same volume that you hear the problem at 30 Hz, how loud would the 2000 Hz tone be? Is it so loud that it is painful? What about 10K Hz?

Humans do not perceive all frequencies at the same level. There is a concept called the "equal loudness contour" that maps the average human perception at different frequencies.




What this graph says is that in order for a human to perceive a ~40 dB SPL tone at 2000 Hz with the same loudness at 20 Hz, the 20 Hz tone has to be at ~100 dB. That's a huge difference.

This is why trying to measure frequency response by ear is a complete waste of time. You really need to do it the way reviewers like Tyll do it - using an instrumented & mic'd head in an anechoic chamber.

It would not surprise me if you are driving the headphones into distortion by trying to get a pure 20 Hz tone to the same level as a 2000 Hz tone. I just hope you haven't already damaged your drivers.

I won't be able to test this for a while as I'm not home, but I don't turn my amp all the way up and turn the sound on. I start it and slowly turn the sound up, and it eventually makes the aforementioned "TAKTAKTAK" sound

 

[ProtegeManiac]

If you were to listen to a tone at 2000 Hz at the same volume that you hear the problem at 30 Hz, how loud would the 2000 Hz tone be? Is it so loud that it is painful? What about 10K Hz?

Humans do not perceive all frequencies at the same level. There is a concept called the "equal loudness contour" that maps the average human perception at different frequencies.

 

I forgot that part - @NineRedTools I assumed you had it on at a level where you can hear the bass on music and then ran the test tone and then going up slightly. At around what part of the dial (based on clock position) did you have it when you ran the test tone vs when you're listening?

 

[NineRedTools]

I forgot that part - @NineRedTools I assumed you had it on at a level where you can hear the bass on music and then ran the test tone and then going up slightly. At around what part of the dial (based on clock position) did you have it when you ran the test tone vs when you're listening?

On the schiit magni, about a 2:00 position maybe. I usually listen at 12:00

 

[ProtegeManiac]

On the schiit magni, about a 2:00 position maybe. I usually listen at 12:00

 
You're basically listening at beyond the normal loudness setting you can take and possibly well into audible distortion; if you did this with music at best you may just not notice it as much since there a lot of other sounds going on.
 
Have you tested it at 12:00 to see if it still distorts with the test tones?

 

[NineRedTools]

You're basically listening at beyond the normal loudness setting you can take and possibly well into audible distortion; if you did this with music at best you may just not notice it as much since there a lot of other sounds going on.

Have you tested it at 12:00 to see if it still distorts with the test tones?

Yes. It doesn't distort at 12. Only once I get it louder. But this cleared things up for me

 

[cel4145]

One common misconception is that just because the dial on an amplifier (headphones or speaker) can go up to a certain point as a max, that does not mean that the amp or the speakers/headphone will not distort long before reaching that point on the dial, depending on (a) the input signal into the amp, (b) the impedance and sensitivity of the speakers/headphones, and/or (c) the volume dial setup (the hardware being used and the gain structure).

 

[ProtegeManiac]

One common misconception is that just because the dial on an amplifier (headphones or speaker) can go up to a certain point as a max, that does not mean that the amp or the speakers/headphone will not distort long before reaching that point on the dial, depending on (a) the input signal into the amp, (b) the impedance and sensitivity of the speakers/headphones, and/or (c) the volume dial setup (the hardware being used and the gain structure).

 
Yep, it may even be distorting before his own limit, but as far as his ears with that system is concerned, 12:00 was his threshold for "audible" distortion vis a vis ambient noise (or it's really just too loud past it).