dt770 DT 770's drivers rattle under relatively extreme conditions.

[D1Wolfgang]

I've had these DT 770's for about 2 months now after some incredible suggestions. I love em. They sound great, look great, and work well. 
But, I noticed that during some bass heavy songs - or when I bass boost with EQ - My (primarily) right driver rattled. It seems like it went away under regular use with a little blowing in the earcup. I tested the bass and my AMP with https://www.szynalski.com/tone-generator/ and https://www.audiocheck.net/soundtests_headphones.php. At normal (100% windows, 50% amp) levels I don't get an issue but as I increase the volume on my amp (closer to 100% windows, 75% to 100% on my amp) I hear crazy distortion and rattling. I assume that's normal and that my amp just can't power my 250 OHM's that high. It's the FX Audio DAC-X6. I have no issue with distortion at those levels since I'll never need it that high, but I want to know if this is normal and ok for my setup or if it's dangerous. If I continue to experience rattling, is there anything I can do besides RMAing them? 
Thanks a ton for any help or input I hope this can help other people with this issue. 

[Spuriae]

Check the inside of your DT770 for loose hair.

[just_dave]

Check for hairs inside the drivers.

Stop using bass EQs because that's how you will destroy things.

Also dont use tone generators, that will destroy things.

Audiophile tip: windows volume ALWAYS 100%

[D1Wolfgang]

2 hours ago, thicc_boi said:

Check for hairs inside the drivers.

Stop using bass EQs because that's how you will destroy things.

Also dont use tone generators, that will destroy things.

Audiophile tip: windows volume ALWAYS 100%

Yeah, I wasn't sure if i could break anything like that. Thanks. I always have Window to 100% just for ease of only my amp knob changing stuff. 

I'll check for hairs.

By the way, do you really think bass eq's are that bad? It's just Peace Eq's default bass boost setting.

[just_dave]

1 hour ago, D1Wolfgang said:

Yeah, I wasn't sure if i could break anything like that. Thanks. I always have Window to 100% just for ease of only my amp knob changing stuff. 

I'll check for hairs.

By the way, do you really think bass eq's are that bad? It's just Peace Eq's default bass boost setting.

If you EQ the bass up (+), then you are pushing more power into the driver at those frequencies. Bass as you probably know has HUUUUUUUUUUUUUUUUUUUUUUUUGEEEEEEEEEEEEEEEEEEEEEEEEE wavelengths, this means the driver moves A LOT.

This puts a lot of stress on the surround (the flexy thing that makes the cone move back and forth) and eventually can tear it, crack it or make the driver jump out of it's movement range and lock it out.

The correct way to do EQs is to keep the boosted part at 0dB and lower the things you dont want down.

Now, for a moment turn off all the stupid EQ shit, play some normally bassy song like Aero Dynamik by Kraftwerk and listen.

Using black magic and physics, you can calculate that the FX Audio X6 is very well capable of blowing up the DT770.

Thats why you hear distortion when you crank it all the way.

The drivers are designed to handle 100mW while the X6 puts out over 200mW at full power @250R.

But, if you listen at 110dB SPL, you should see a doctor, because that's not normal.

 

 

 

[just_dave]

Also, this is the more correct way to do EQ

 

[D1Wolfgang]

7 minutes ago, thicc_boi said:

The correct way to do EQs is to keep the boosted part at 0dB and lower the things you dont want down.

Aight. I see what you're saying.

8 minutes ago, thicc_boi said:

Now, for a moment try to be a sentient being and turn all off the stupid EQ shit off, play some normally bassy song like Aero Dynamik by Kraftwerk.

Ok, lets try to imagine I'm not an audio professional and I just follow guides from the internet.

 

Thanks for your help. Imma link some images. I think I understand what you were saying. The V is a no, the Decreasing one is a yes? And how about the eq I got from that huge headphone eq reddit thread? 

 

[D1Wolfgang]

Just now, thicc_boi said:

Also, this is the more correct way to do EQ

 

lol thanks. in that case ignore my questions about how to do it. still tho... how come so many people have guides on boosting bass like the first thing? 

[just_dave]

19 minutes ago, D1Wolfgang said:

lol thanks. in that case ignore my questions about how to do it. still tho... how come so many people have guides on boosting bass like the first thing? 

You can do it, but it's bad for your case since you have nearly blown your headphones up.

Also, its usually preffered to not EQ your headphones and just enjoy them the way they are.

[D1Wolfgang]

Just now, thicc_boi said:

You can do it, but it's bad for your case since you have nearly blown your headphones up.

 

keyword: nearly. No damage done  I learned a lesson 

[pas008]

2 hours ago, thicc_boi said:

Check for hairs inside the drivers.

Stop using bass EQs because that's how you will destroy things.

Also dont use tone generators, that will destroy things.

Audiophile tip: windows volume ALWAYS 100%

agreed

but if its another analog signal being amped like using onboard card with amp then you would be amping that noise wouldnt you?

 

 

 

[just_dave]

1 minute ago, pas008 said:

agreed

but if its another analog signal being amped like using onboard card with amp then you would be amping that noise wouldnt you?

 

 

 

Depends.

If you have a DAC (or an onboard card), those will have some noise floor. But your amplifier has also noise floor.

If you play full blast from your dac, you can turn the volume knob on your amplifier down, which will minimize the noise coming from the amplifier. That is usually greater than the DAC noise floor, so you want the DAC to be as loud as possible and just control it on the amplifier.

The biggest problem with windows volume control is that it cuts the bit depth (which gives the sound amplitude in digital to analog conversion), effectively lowering the quality of the digital files.

Imagine that a 16 bit 44Khz file played at 60% will be like 12 or 14 bit, therefore reduced quality. This reduced bit depth introduces the quantization noise. The higher the bit depth, the lower the quant. noise.

 

[just_dave]

9 minutes ago, D1Wolfgang said:

keyword: nearly. No damage done  I learned a lesson 

well you dont know for sure

[D1Wolfgang]

1 minute ago, thicc_boi said:

well you dont know for sure

at normal volume it sounds fine. Any tips on what I should listen for? 

[just_dave]

1 minute ago, D1Wolfgang said:

at normal volume it sounds fine. Any tips on what I should listen for? 

ok. Have you messed with the FX Audio X6 on the inside?

[D1Wolfgang]

Just now, thicc_boi said:

ok. Have you messed with the FX Audio X6 on the inside?

Not at all. 

[just_dave]

Just now, D1Wolfgang said:

Not at all. 

You can get yourself different op-amps and improve the sound quality for just a few bucks, here are some useful links.

Dont do the trick that makes the amp even louder though, youll blow your head off.

https://www.reddit.com/r/headphones/comments/af5sxm/fx_audio_dacx6_op_amp_rolling/

[D1Wolfgang]

7 minutes ago, thicc_boi said:

You can get yourself different op-amps and improve the sound quality for just a few bucks, here are some useful links.

Dont do the trick that makes the amp even louder though, youll blow your head off.

https://www.reddit.com/r/headphones/comments/af5sxm/fx_audio_dacx6_op_amp_rolling/

I meant I didn't think it was broken, because it sounded fine and was wondering if I should listen for anything specific to tell if it's broken.

[just_dave]

Just now, D1Wolfgang said:

I meant I didn't think it was broken, because it sounded fine and was wondering if I should listen for anything specific to tell if it's broken.

Aero Dynamik

 

[just_dave]

Also, try the iPad Pro commerical. The intro has a lot of bass.

[Spuriae]

5 hours ago, thicc_boi said:

Check for hairs inside the drivers.

Stop using bass EQs because that's how you will destroy things.

Also dont use tone generators, that will destroy things.

Audiophile tip: windows volume ALWAYS 100%

Digital Bass EQ cannot destroy anything that would not have been destroyed under other normal conditions; digital output cannot exceed full-scale. Early clipping distortion, yes; destruction, no.

 

What's wrong with tone generators?

 

Windows volume usually 100%, but there are plenty of exceptions. Compared to many analog volume controls (resistor noise) and some digital ones (limited precision), 32 bit software volume control sometimes comes out looking pretty good.

 

3 hours ago, thicc_boi said:

Using black magic and physics, you can calculate that the FX Audio X6 is very well capable of blowing up the DT770.

Thats why you hear distortion when you crank it all the way.

The drivers are designed to handle 100mW while the X6 puts out over 200mW at full power @250R.

The X6 can't output 200mW at 250Ω; it doesn't have enough voltage headroom. 100mW into 250Ω requires 5Vrms swing, which is impossible on a 12V input linear supply. It can only manage this power level on lower impedance loads where it can supply more current. The headphones can handle more than that 100mW number anyhow; it's really more of a guideline to avoiding clipping.

 

2 hours ago, thicc_boi said:

Depends.

If you have a DAC (or an onboard card), those will have some noise floor. But your amplifier has also noise floor.

If you play full blast from your dac, you can turn the volume knob on your amplifier down, which will minimize the noise coming from the amplifier. That is usually greater than the DAC noise floor, so you want the DAC to be as loud as possible and just control it on the amplifier.

The biggest problem with windows volume control is that it cuts the bit depth (which gives the sound amplitude in digital to analog conversion), effectively lowering the quality of the digital files.

Imagine that a 16 bit 44Khz file played at 60% will be like 12 or 14 bit, therefore reduced quality. This reduced bit depth introduces the quantization noise. The higher the bit depth, the lower the quant. noise.

 

In almost all amplifiers, the volume knob precedes the amplification stage. Turning this down increases the Johnson noise of the amplifier (and degrades channel balance).

 

Audio DACs produced today are delta-sigma and do not have this kind of quantization noise due to heavy oversampling. If you're using 32 bit words the 16 bit file is really a 32 bit signal with 16 0's following the initial data. Reducing the volume shifts the values down but does not reduce dynamic range. Floating point rounding errors are the only significant drawback in this case, and these are usually dwarfed by other noise sources.

[Derkoli]

6 hours ago, D1Wolfgang said:

lol thanks. in that case ignore my questions about how to do it. still tho... how come so many people have guides on boosting bass like the first thing? 

Some people love bass. I like bass digging deep and being balanced with the rest of the frequency range, but not louder/higher Db as the rest of the frequency range. Bass boosting will NOT destroy anything, unless you feed the driver more power than it can handle. Feeding a driver with power handling of 15W with a 10W amplifier with extreme bass boosting applied wont break anything. Granted the amplifier and driver might get warm, but this is normal.

TL;DR: Bass boosting is 100% fine, EQ everything you want. Just dont apply so much bass that distortion starts to happen, Distortion doesnt break anything but isnt very fun to listen to.

[just_dave]

8 hours ago, Nimrodor said:

The X6 can't output 200mW at 250Ω; it doesn't have enough voltage headroom. 100mW into 250Ω requires 5Vrms swing, which is impossible on a 12V input linear supply. It can only manage this power level on lower impedance loads where it can supply more current. The headphones can handle more than that 100mW number anyhow; it's really more of a guideline to avoiding clipping.

What?  The official specs list 180mW/300R and 450mW/100R.

That is around 6.7Vrms at 100R and over 7Vrms at 300R, 7.3Vrms at 600R.

The DT770 is rated for 5Vrms/100mW/107dB SPL

If he is pushing them over the limit, not wonder he's got rattling and distortion.

9 hours ago, Nimrodor said:

amplification stage. Turning this down increases the Johnson noise of the amplifier (and degrades channel balance).

Channel balance maybe, Johnson resistor noise? Not a chance.

I was repairing a vintage HK 6500 amplifier once.

It had a 100K volume pot and fully bipolar preamp w/tone control stage.

The more i turned the knob up (and increased the input impedance), the higher the noise output from the preamp was.

I have a Magni 2 Uber, fully bipolar headphone amp, and even on low gain with IEMs, the more you turn the amp up, the more noise you get.

6 hours ago, Derkoli said:

Just dont apply so much bass that distortion starts to happen, Distortion doesnt break anything but isnt very fun to listen to.

Yes, but in his case, if he pushes more bass power it's bad since the amp can damage the headphones already. Pushing more frequencies which can easily break stuff is no good

 

9 hours ago, Nimrodor said:

Audio DACs produced today are delta-sigma and do not have this kind of quantization noise due to heavy oversampling. If you're using 32 bit words the 16 bit file is really a 32 bit signal with 16 0's following the initial data. Reducing the volume shifts the values down but does not reduce dynamic range. Floating point rounding errors are the only significant drawback in this case.

Yeah youre probably righy my dac knowledge is old school.

 

Also, i blew up 60W speaker with 70W of music with basically no bass at all.

[D1Wolfgang]

Thank you all. I've taken away that digital apps can't break the headphones with EQ, however, if I boost my AMP to 100%, which is not necessary, my drivers could damage themselves.

7 hours ago, Derkoli said:

Just dont apply so much bass that distortion starts to happen, Distortion doesnt break anything but isnt very fun to listen to.

I see what you mean with the Bass evening out with the rest of the music - which I enjoy, but i also like some louder bass too. Something I can feel. 

Thanks for the help! I love learning about new topics. I feel I'm pretty well versed in PC hardware, but I like learning about audio now  

[Spuriae]

9 hours ago, thicc_boi said:

What?  The official specs list 180mW/300R and 450mW/100R.

That is around 6.7Vrms at 100R and over 7Vrms at 300R, 7.3Vrms at 600R

Those are almost definitely false or manipulated in some way. 7.3Vrms is physically impossible using their parts. Most likely they are summing the outputs of both channels when giving their power output spec, not using a standard test signal for power measurements, or simply don't care about lying.

 

Measurements show that the voltage swing is limited to what would be expected for a 12V device.

9 hours ago, thicc_boi said:

Channel balance maybe, Johnson resistor noise? Not a chance.

Model a pot in series with a 0Ω output source and calculate the resistor noise. At full volume the network's effective impedance is 0.

12 hours ago, thicc_boi said:

I was repairing a vintage HK 6500 amplifier once.

It had a 100K volume pot and fully bipolar preamp w/tone control stage.

The more i turned the knob up (and increased the input impedance), the higher the noise output from the preamp was.

I have a Magni 2 Uber, fully bipolar headphone amp, and even on low gain with IEMs, the more you turn the amp up, the more noise you get.

The noise was higher even with no signal being played?

 

Raising the volume also doesn't strictly increase input impedance; it depends on the input device's input impedance. For instance, if there is a 10kΩ impedance looking into the BJT's base, then input impedance is lower at full volume (10kΩ||100kΩ) than at half (50kΩ+50kΩ||10kΩ).