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Sennheiser HD800S Review (Headphone)

ParadoxDelta

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Supposedly, V200 has more power than A90 with single ended output. If you encounter the same distortion at around the same level, I think you can eliminate the amplifier being issue.
I think it can be the driver. So I guess tame the eq a bit and see if that helps.
Thank you very much. I'm still curious: What is the expected behaviour of a headphone that gets more power than it can handle?
 

solderdude

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Then it will sound VERY, VERY loud and distorted.

HD800S can handle 12V continuous and will have no problems with short peaks reaching 16V
SPL will be well over 125dB SPL so safe to say you will never reach that in practice.
 

Jimbob54

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Your Topping A90 and an old Violectric V200

Just one more thing to check before you conclude its the headphones themselves. You're not getting digital clipping are you? Try increasing the size of the preamp reduction in your EQ set up, rule out illegal samples due to boosted peaks being your problem.
 

ParadoxDelta

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Alright I managed to take a closer look at the drivers and discovered tiny dents in the membrane around the inner circle under heavy bass load. I'm pretty sure they cause the distortion. I did a short video of the issue. The dents appear around 5s into the video (especially visible with slower video speed). Faulty driver or too much load?
 

solderdude

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It's likely to be audible.

Can't say how loud it is though. Most likely beyond the 104dB Amir tested it at. Looks like maximum excursion is reached.
Question. Does this happen on both drivers at approx. the same level ?
If that's the case then the drivers aren't faulty you are just hitting max excursion limits.
When you crank up the low bass really a lot you may have reached max excursion way before the power rating is exceeded.
 

maverickronin

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Alright I managed to take a closer look at the drivers and discovered tiny dents in the membrane around the inner circle under heavy bass load. I'm pretty sure they cause the distortion. I did a short video of the issue. The dents appear around 5s into the video (especially visible with slower video speed). Faulty driver or too much load?

Agreeing with @solderdude. That looks like maximum excursion to me.

Are you EQing up the bass a lot? Also, what were they playing in that video? Music, test signal, etc.
 

Jimbob54

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Alright I managed to take a closer look at the drivers and discovered tiny dents in the membrane around the inner circle under heavy bass load. I'm pretty sure they cause the distortion. I did a short video of the issue. The dents appear around 5s into the video (especially visible with slower video speed). Faulty driver or too much load?

Yup, like solderdude says, looks like the drivers are being pushed too hard. Try keeping the amp volume the same as what makes it do that now and see how many dB you have to dial back the bass EQ before it doesnt do that. Essentially the same issue as was found in the Focal Clear review here. I'm not going to torture myself by seeing if my HD800 do the same (my Clear did) .
 

ParadoxDelta

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It's likely to be audible.

Can't say how loud it is though. Most likely beyond the 104dB Amir tested it at. Looks like maximum excursion is reached.
Question. Does this happen on both drivers at approx. the same level ?
If that's the case then the drivers aren't faulty you are just hitting max excursion limits.
When you crank up the low bass really a lot you may have reached max excursion way before the power rating is exceeded.
Yes, they do. The right driver a little earlier than the left. The maximum volume depends on the kind of song I'm playing. Here I used Deadmau5 - Polaris since I can hear the issue with this song quite early and cut the tremble with a low-pass-filter for better audibility. This song normaly reaches peak at ~105dB before distorting (measured with my cheap volume level meter). I'm not using any EQ in this example. The more tremble and the less bass a song has, the louder it goes without distorting.
 

Jimbob54

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Yes, they do. The right driver a little earlier than the left. The maximum volume depends on the kind of song I'm playing. Here I used Deadmau5 - Polaris since I can hear the issue with this song quite early and cut the tremble with a low-pass-filter for better audibility. This song normaly reaches peak at ~105dB before distorting (measured with my cheap volume level meter). I'm not using any EQ in this example. The more tremble and the less bass a song has, the louder it goes without distorting.

Now, did you do the mod you mentioned or buy them as is? And if you did it did you test/ notice this pre mod?
 

ParadoxDelta

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Now, did you do the mod you mentioned or buy them as is? And if you did it did you test/ notice this pre mod?
I inserted the mod rings myself but the issue existed before that. The superdupont mod doesnt interfere with the driver. They try to imitate the dupont resonators of the HD800S. They are basically foam rings with a paper-bottom and you insert them in the middle of the protective frame (the driver has a hole in the middle).
 

solderdude

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105dB before distorting (measured with my cheap volume level meter)

Most likely peaks are exceeding the indicated levels by the meter.
You need to calibrate first.

When you don't have access to an oscilloscope a good way is to use the calibration method described by @Robbo99999 here.

Then we can figure out how loud you are really playing.
 

ParadoxDelta

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Most likely peaks are exceeding the indicated levels by the meter.
You need to calibrate first.

When you don't have access to an oscilloscope a good way is to use the calibration method described by @Robbo99999 here.

Then we can figure out how loud you are really playing.
How do I calculate die maximum voltage the Topping A90 is able to deliver on my 300ohm HD800? I'm a little confused what to use per ear with balanced unbalanced and so on. The product info states 2x1000mw for balanced on 300ohm.
 
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Robbo99999

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How do I calculate die maximum voltage the Topping A90 is able to deliver on my 300ohm HD800? I'm a little confused what to use per ear with balanced unbalanced and so on. The product info states 2x1000mw for balanced on 300ohm.
If you were gonna be using my method, (take a look at my post that solderdude linked in his message to you)....if you're gonna use my method then you need to know how many volts your DAC outputs at 0dBFS and 100% Windows Volume, max volts of the DAC. Then for your Topping A90 headphone amp you'd need to research which of the Gain Settings is Unity Gain, and you'd set your A90 to max volume on Unity Gain setting. And then you'd follow the steps outlined in my post that solderdude linked.

(Actually, got me thinking, I'm not sure if I know for sure the max voltage output of my SoundblasterX G6 DAC, I did think it was 2V based on Amir's review, but now I'm not so sure, I'll ask over in the G6 thread. EDIT: G6 does output 2V at max, worked it out from the various DAC reviews, the dashboard in Amir's reviews is showing the max voltage)
 
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solderdude

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How do I calculate die maximum voltage the Topping A90 is able to deliver on my 300ohm HD800?

It's in the datasheet (as Vpp).
SE = 8.8V
Bal = 17V
Do note that the HD800 is NOT designed to handle 17V continuous but short peaks are allowed in music and this will not burn the voicecoil but calculated SPL would be 130dB SPL of which I am sure it will not do.
 

ParadoxDelta

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I switched to unbalanced connector for easier understanding.
When I have the Amp on High Gain and max volume, the distortion starts at Windows volume 83/100. Is there a way to convert this in dBfs? (in EqualizerAPO the distortion starts at -3dB when Windows volume is 100 wich might be the value, I suppose)

I also put some test tones in there (1000, 500, 100, 20Hz) and measured the voltage on the 2 membrane contacts of the left driver. The raw AC value here is 5,0V for each test tone just before the distortion starts. My test song is around 4V (3V-4.6V) with this setting. Are these measurement of any use or do I still have to integrate the resistance in the calculation?

When I set everything to max, the AC value for test tones is 8,3V wich comes close to the advertised 8.8V. Or am I on the wrong path?
 
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solderdude

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Play music which shows the distortion.
Set the volume to the level where it starts to distort.
Leave all volume controls at that position.
Now play a test tone (0dB) of 100Hz.
Measure the output voltage of the amp (the HD800 does not need to be connected)
Now you know what peak values are present in the offending recording and at what SPL this happens.

At 5V you are already hitting 119dB SPL

The used AC voltmeter should have a 2VAC range as well.
When it only has 200VAC (so not DC) as the lowest voltage range the readings are somewhat 'off'.
 

Tigi

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It's in the datasheet (as Vpp).
SE = 8.8V
Bal = 17V
Do note that the HD800 is NOT designed to handle 17V continuous but short peaks are allowed in music and this will not burn the voicecoil but calculated SPL would be 130dB SPL of which I am sure it will not do.

Just to avoid any confusion, the A90´s technical specification states the following figures concerning the maximum output level (high gain):
Vpp (peak-to-peak): 25V in SE mode and 49V in balanced mode.
The figures you mentioned (8,8V and 17,3V) are derived RMS voltage numbers (VRMS = Vpp/(2*sqrt(2))).
 

solderdude

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Correct. Vpp values from the datasheet calculated to Vrms.
As 350 ohm is virtualy no load to the A90 these are the values that can be reached.
 

ParadoxDelta

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Ok, just measuring the voltage seems far easier to me, than deriving it from the Amp specs. According to the linked tool, volume at 5V should hit 116dB. This, to me, would be a more reasonable clipping volume than the 105 dB that my sound level meter showed. Are these calculations based on the 102 dB at 1 Vrms spec somewhat reliable?
2021-05-21 12_27_12-Window.png
 

Robbo99999

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Ok, just measuring the voltage seems far easier to me, than deriving it from the Amp specs. According to the linked tool, volume at 5V should hit 116dB. This, to me, would be a more reasonable clipping volume than the 105 dB that my sound level meter showed. Are these calculations based on the 102 dB at 1 Vrms spec somewhat reliable? View attachment 131090
One relatively large variable could be the sensitivity of the headphone. For instance, my K702 has a sensitivity of 105dB/V according to the manufacturer, but when Oratory measured my headphone it's real sensitivity is 102.2dB/V, so a difference of 2.8dB. However, Oratory measured the sensitivity of an HD800s and he ended up with a very similar reading to what Amir got, which was close to the manufacturers spec if I recall rightly. If you think that variable of difference is larger or smaller than the accuracy of your sound meter then that's your decision.
 
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