Headphones

Started by Bonehelm, June 10, 2007, 02:50:21 PM

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Ken B

Quote from: North Star on June 05, 2015, 07:18:14 PM
You're right! It isn't! It has nothing to do with 'subsidizing the rich'. Offering all people an equal opportunity to get an education, a job and to make money (some 50% of it for the society) is not the same thing as subsidizing the rich any more than scholarships for poor American kids are subsidies for the rich.
Nonsense. Scholarships for the poor are for ... The poor. Free tuition for Bill Gates Jr is for ... The rich.

Mirror Image

Good lord! Let's not turn this into a political discussion. Let's get back to discussing headphones. Leave it to Ken to derail a thread. ::)

Ken B

Quote from: Mirror Image on June 05, 2015, 08:48:25 PM
Good lord! Let's not turn this into a political discussion. Let's get back to discussing headphones. Leave it to Ken to derail a thread. ::)

As long as no-one suggests free headphones for the rich, I'm down with that.  >:D

My set at work are not great. I wonder though if I need closed not open ones, due to the presence of pesky co-workers.

Mirror Image

Quote from: Ken B on June 05, 2015, 08:53:59 PM
As long as no-one suggests free headphones for the rich, I'm down with that.  >:D

My set at work are not great. I wonder though if I need closed not open ones, due to the presence of pesky co-workers.

You would need closed-back headphones for a work environment, Ken. If you don't mind people being able to hear what you're listening to, then open-back headphones are the way to go. Personally, I wouldn't buy a pair of closed-back for the simple reason that I like headphones that breathe and that have a natural soundstage.

71 dB

Quote from: Ken B on June 05, 2015, 04:55:23 PM
Thanks.
You are welcome.

Quote from: Ken B on June 05, 2015, 04:55:23 PMFree university? How unfortunate. That means the average taxpayer subsidizes lawyers, actuaries, lasik surgeons, and the children of the rich. That this is seen as a good thing by many I attribute to tribalism -- we with degrees are superior beings -- and snobbery -- degrees produce superior beings. I prefer government spending to help the poor and those who fall between the cracks; I'm a cold unfeeling right-winger that way.
Well, we finns see this as the secret of our success. Poor people can be extremely talented, so for a nation it's wise to make it possible for those telanted people to get themselves educated. Rich people can pay taxes, they have monet, they are the fortunate ones.
Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

The new erato

Quote from: Ken B on June 05, 2015, 04:55:23 PM
Thanks.
Free university?
in Norway too

Quote from: Ken B on June 05, 2015, 04:55:23 PM
That means the average taxpayer subsidizes lawyers, actuaries, lasik surgeons, and the children of the rich.
That could be said of every state service. That's why we have a tax system with progressive taxes. You should try it. As an added bonus we have an educated work force with the highest labor participation in the world. 

chadfeldheimer

#826
Quote from: 71 dB on June 05, 2015, 01:00:55 PM
The trick is to use impedance reduction (=extension cable with resitors between signal and ground reducing the impedance seen by the phones) with low impedance phones. The output impedance of the headphone amp should be 1/8 of the impedance of the phones at most. 50 Ω cans need an amp with output impedance of 6 Ω or less.

Say your amp has an output impedance of 50 Ω. Using reduction resistors of 6.8 Ω gives effective output impedance:

50 Ω*6.8 Ω/(50 Ω+6.8 Ω) = 6 Ω.
Having a technical background too, I also thought about solving the problem in a similar way, but I don't think it is this simple. The 50ohms are the dc impedance of the phones, otherwise the impedance of the HD595 is highly frequency depended, having a peak of around 220ohms at 100Hz. If I would insert a resistor network I would dent the characteristics of the phones. Also putting a 6.8ohms resistor in parallel to the phones would mean quite an enormous load for the amplifier, which in this case could be overdriven at higher volume. Thereby also the effectiveness of the phones would decrease considerably, which however should not be such a problem, because the amplifier is mains supplied.

As for the amplifiers (Asus Xonar Essence One) output impedance I would assume it is very low, because there is an opamp-circuit used which naturally has a very low ohmic output, when not overdriven. However I did not find a specified value there.

Quote
It's good you are happy. It's damping factor thing. You blamed your Sennheiser cans when your headphone amp is to blame. The Sennheisers have all the detail when driven from low output impedance amp (e.g. Corda Jazz). My selfmade headphone adapter has an output impedance of 1 Ω + crossfeed at 6 different levels and my Sennheiser HD 598 produce insane amount of detail. There is no need to spend much money when you know what you are doing.  ;)
I do not blame the Sennheisers but rather the combination of Xonar Essence One and HD595. However I think the problem is not in the output impedance of the amplifier but in the high output voltage range it is designed for (7Vrms) with the goal to even drive high ohmic phones. With low ohmic phones you just use a very small part of that output voltage range and therefore the SNR gets limited.

71 dB

Quote from: Mirror Image on June 05, 2015, 09:28:58 PM
Personally, I wouldn't buy a pair of closed-back for the simple reason that I like headphones that breathe and that have a natural soundstage.

Open cans leak more noise from the environment and that noise "augments" the soundstage. That's my theory. Technically I can't think of a reason why open cans would "breathe" more of have a more natural soundstage. Some people speculate open cans crossfeed themselves a bit acoustically leaking sound to the other ear making them sound more open, but that effect is much weaker than proper crossfeed.

The best headphones tend to be open. I think it's more of a design philosophy than a technical thing.
Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

mc ukrneal

Quote from: Mirror Image on June 05, 2015, 09:28:58 PM
You would need closed-back headphones for a work environment, Ken. If you don't mind people being able to hear what you're listening to, then open-back headphones are the way to go. Personally, I wouldn't buy a pair of closed-back for the simple reason that I like headphones that breathe and that have a natural soundstage.
I'd go for open for a totally different reason - I find they are generally more comfortable. In a work environment, I also prefer to hear the sounds around me if I need to (so no one sneaking up on me) and to wear smaller cans on the head.
Be kind to your fellow posters!!

71 dB

Quote from: chadfeldheimer on June 06, 2015, 01:33:39 AM
Having a technical background too, I also thought about solving the problem in a similar way, but I don't think it is this simple.

Believe me, it is this simple. It works in theory and it works in real life.

Quote from: chadfeldheimer on June 06, 2015, 01:33:39 AMThe 50ohms are the dc impedance of the phones, otherwise the impedance of the HD595 is highly frequency depended, having a peak of around 220ohms at 100Hz.

This is one reason you need as low output impedance as possible with such headphones. If the output impedance was zero, all the voltage would always be over the cans and the frequency dependent impedance of the cans wouldn't matter at all. If the output impedance is say 47 Ω, you have a frequency response error of

20*log10((220*50+220*47)/(220*50+50*47)) dB = 4.1 dB,

and that is a lot, about 5-10 times more than what is accebtable.

The impedance curve of my Sennheiser HD 598 is even more frequency dependent (varies between 60 Ω and 280 Ω). Having an output impedance of just 1 Ω in my headphone adapter takes care of this and the frequency response error is 0.1 dB.

Quote from: chadfeldheimer on June 06, 2015, 01:33:39 AMIf I would insert a resistor network I would dent the characteristics of the phones.
Yes, you would, to the better, what the phones are supposed to sound. Sennheiser says their phones are supposed to be driven from low impedancies.

Quote from: chadfeldheimer on June 06, 2015, 01:33:39 AMAlso putting a 6.8ohms resistor in parallel to the phones would mean quite an enormous load for the amplifier, which in this case could be overdriven at higher volume.
Possibly, if your amp is weak, but then again you are planning to use that amp with high impedance cans which tend to be insensitive.

The resistors cause large drop in sensitivity:

20*log10(6/(6+47)) = -18.9 dB, compared to 20*log10(50/(50+47)) = -5.8 dB. About 13 dB difference. In most cases this is no issue.

Since the output impedance of your amp is rather high, the load isn't much of a deal. You could short-circuit the terminals without problems, the current would not get that high.

Quote from: chadfeldheimer on June 06, 2015, 01:33:39 AMThereby also the effectiveness of the phones would decrease considerably, which however should not be such a problem, because the amplifier is mains supplied.

Yes, correct. We don't listen to sensitivity, we listen to sound quality. Almost always in audio high sensitivity means compromises in sound quality.

Quote from: chadfeldheimer on June 06, 2015, 01:33:39 AMAs for the amplifiers (Asus Xonar Essence One) output impedance I would assume it is very low, because there is an opamp-circuit used which naturally has a very low ohmic output, when not overdriven. However I did not find a specified value there.
I do not blame the Sennheisers but rather the combination of Xonar Essence One and HD595. However I think the problem is not in the low output impedance of the amplifier but in the high output voltage range it is designed for (7Vrms) with the goal to even drive high ohmic phones. With low ohmic phones you just use a very small part of that output voltage range and therefore the SNR gets limited.

I found this:

http://www.stereophile.com/content/asus-xonar-essence-one-muses-edition-da-processor150headphone-amplifier-measurements

It says the output impedance of your amp is 11.1 Ω. So, it's not very high nor is it very low. It's a bit too high for Sennheiser HD 595.

Now you say the SNR was the problem. Well, this kind of SNR issues are well corrected with the parallel resistors I have been talking about. In this case where the output impedance is 11.1 Ω, the parallel resistors could be 12 Ω giving an effective output impedance of

11.1*12/(11.1+12) Ω = 5.8 Ω (damping factor criteria fulfilled)

This causes 4.9 dB attennuation meaning the noise floor drops down this much hopefully becoming unnoticed. If not, then smaller paraller resistors are needed (10 Ω...8.2 Ω...)

Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

chadfeldheimer

#830
Quote from: 71 dB on June 06, 2015, 02:50:38 AM
Believe me, it is this simple. It works in theory and it works in real life.
Sorry - I'm still sceptical.
Quote
This is one reason you need as low output impedance as possible with such headphones. If the output impedance was zero, all the voltage would always be over the cans and the frequency dependent impedance of the cans wouldn't matter at all. If the output impedance is say 47 Ω, you have a frequency response error of

20*log10((220*50+220*47)/(220*50+50*47)) dB = 4.1 dB,

and that is a lot, about 5-10 times more than what is accebtable.

The impedance curve of my Sennheiser HD 598 is even more frequency dependent (varies between 60 Ω and 280 Ω). Having an output impedance of just 1 Ω in my headphone adapter takes care of this and the frequency response error is 0.1 dB.
Yes, you would, to the better, what the phones are supposed to sound. Sennheiser says their phones are supposed to be driven from low impedancies.
Ok - seems you are right there, but having a 12times higher ohmic phone would also solve the problem. Besides the impedance of the DT880 changes much less with frequency than that of the HD595.
Quote
Possibly, if your amp is weak, but then again you are planning to use that amp with high impedance cans which tend to be insensitive.
Yes the sensitivity of the HD595 with 104dB is considerably higher than that of the DT880, which however has the same sensitivity for all versions 32, 250 or 600 ohms.
Quote
The resistors cause large drop in sensitivity:

20*log10(6/(6+47)) = -18.9 dB, compared to 20*log10(50/(50+47)) = -5.8 dB. About 13 dB difference. In most cases this is no issue.

Since the output impedance of your amp is rather high, the load isn't much of a deal. You could short-circuit the terminals without problems, the current would not get that high.
I would not be so sure about it. The maximum voltage range of the amplifier is 7Vrms. A full-scale signal would produce a RMS-current of 412mA through the 6 ohms load + 11 ohms amplifier output impedance which is pretty high imo.
Quote

We don't listen to sensitivity, we listen to sound quality. Almost always in audio high sensitivity means compromises in sound quality.

Yes - that would be more relevant for portables.
Quote

I found this:

http://www.stereophile.com/content/asus-xonar-essence-one-muses-edition-da-processor150headphone-amplifier-measurements

It says the output impedance of your amp is 11.1 Ω. So, it's not very high nor is it very low. It's a bit too high for Sennheiser HD 595.
Ok thanks for checking this. In fact I don't have the muses edition, but let's assume the output impedance is the same.
Quote
Now you say the SNR was the problem. Well, this kind of SNR issues are well corrected with the parallel resistors I have been talking about. In this case where the output impedance is 11.1 Ω, the parallel resistors could be 12 Ω giving an effective output impedance of

11.1*12/(11.1+12) Ω = 5.8 Ω (damping factor criteria fulfilled)

This causes 4.9 dB attennuation meaning the noise floor drops down this much hopefully becoming unnoticed. If not, then smaller paraller resistors are needed (10 Ω...8.2 Ω...)
4.9dB is not that much considering the fact, that switching from a 50ohms to a 600ohms phone would bring a SNR improvement of 10.7dB, because it increases with the driving voltage that rises with the sqaureroot of the impedance at fixed volume. To get the same SNR-improvement with an inserted parrallel resistor, this one would have to be considerably lower than 12ohms and a full-scale signal would produce a quite a high current, stressing the output drivers and the output resistors (I assume they used some for protecting against shorts, hopefully adequately dimensioned) of the amplifier. This seems to me the price for the simple solution.

Mirror Image

Quote from: 71 dB on June 06, 2015, 01:40:23 AM
Open cans leak more noise from the environment and that noise "augments" the soundstage. That's my theory. Technically I can't think of a reason why open cans would "breathe" more of have a more natural soundstage. Some people speculate open cans crossfeed themselves a bit acoustically leaking sound to the other ear making them sound more open, but that effect is much weaker than proper crossfeed.

The best headphones tend to be open. I think it's more of a design philosophy than a technical thing.

Ah, but when you go hear a live concert can you hear the noise around you, can you not? This creates a more natural listening experience. I never have liked closed headphones and it is my belief that the soundstage is wider. This is especially evident when I listen to classical music. If I were to listen to the pop music you listen to, then it wouldn't matter what kind of headphones I used as most pop records sound like crap to begin with.

Ken B

Quote from: The new erato on June 06, 2015, 01:28:18 AM
in Norway too
That could be said of every state service. That's why we have a tax system with progressive taxes. You should try it. As an added bonus we have an educated work force with the highest labor participation in the world.

Actually no. It is not true of every state service. It is not true of a guaranteed income implemented by a progressive negative tax.

71 dB

Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AM
Sorry - I'm still sceptical.
What exactly are you sceptical about? You haven't demonstrated errors in my calculations (please do so if you find any). What I am speaking about is based on my own experiences with these parallel resistors, my insight of the issue. It takes 2 resistors, a headphone extension cable and 5 minutes with a soldering iron to verify my words.

Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AMOk - seems you are right there, but having a 12times higher ohmic phone would also solve the problem. Besides the impedance of the DT880 changes much less with frequency than that of the HD595.
Your solution is probably very effective (nothing wrong about it!) but my solution costs maybe 1 % of your solution. Those who are not interested in saving money can pass my suggestions.

Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AMYes the sensitivity of the HD595 with 104dB is considerably higher than that of the DT880, which however has the same sensitivity for all versions 32, 250 or 600 ohms.
Beyerdynamics seems to give the sensitivity of 96 dB/mW @ 500 Hz. Voltage sensitivity of course is not the same. 1 Vrms means 31 mW to 32 Ω, 4 mW to 250 Ω and barely 2 mW to 600 Ω meaning 32 Ω version is almost 13 dB louder with the same voltage as 600 Ω version.

I believe the sensitivity of 50 Ω HD595 is 112 dB/1 Vrms => 112 dB/20 mW = 99 dB/mW, which is only 3 dB more than DT880, but where HD595 gives 92 dB/0.1 Vrms, 600 Ω DT880 gives "only" 78 dB/0.1 Vrms! 

Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AMI would not be so sure about it. The maximum voltage range of the amplifier is 7Vrms. A full-scale signal would produce a RMS-current of 412mA through the 6 ohms load + 11 ohms amplifier output impedance which is pretty high imo.

First of all, you damage your hearing long before the amperes cause problems. Secondly, music is dynamic signal, especially classical music. the average power is less than 1 % of the peak power. The resistors don't mind if you heat them up 1 ms every now and then.

The 6.8 Ω parallel resistors were suggested for 47 Ω output impedance. Since the output impedance is 11.1 Ω, I revised the resistors to 12 Ω. Theoretically 7 V would mean 337 mA and about 3.3 V over the phones (117 dB). Nobody in their right mind turns the volume that high when listening to sensitive cans.  ::)

Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AMYes - that would be more relevant for portables.
Portable devices need low impedance phones, typically 32 Ω. 

Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AMOk thanks for checking this. In fact I don't have the muses edition, but let's assume the output impedance is the same.

Oh, not exactly the same device. I'm sure 11.1 Ω applies to your amp too. It's the same assembly line making these models.


Quote from: chadfeldheimer on June 06, 2015, 06:13:09 AM4.9dB is not that much considering the fact, that switching from a 50ohms to a 600ohms phone would bring a SNR improvement of 21,5 dB. To get the same SNR-improvement with an inserted  parrallel resistor, this one would have to be roughly 1/12 of the amplifiers output impedance - so around 1 ohms. In that case a full-scale signal would produce a RMS-current of 583mA through the 1 ohms load + 11 ohms amplifier output impedance would be flowing, stressing the output drivers and the output resistors (I assume they used some for protecting against shorts, hopefully adequately dimensioned) of the amplifier. This seems to me the price for the simple solution.
I don't follow your calculations (how did you get 21.5 dB?) or what you mean about SNR. Do you hear noise caused by the amp when you listen to HD595? Now, how many decibels does this noise exceed threshold of hearing?

Above I calculated that 50 Ω HD595 is 14 dB louder than 600 Ω edition of DT880. Now, there is source impedance attenuation of 1.7 dB for HD595 and 0.2 dB for DT880 meaning HD595 is 12.5 dB louder than DT880 when driven from your amp. If you used the 12 Ω parallel resistors with HD595, the source impedance attenuation is 6.6 dB meaning it would be 7.6 dB louder than DT880 directly.
Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

71 dB

Quote from: Mirror Image on June 06, 2015, 06:20:20 AM
Ah, but when you go hear a live concert can you hear the noise around you, can you not? This creates a more natural listening experience. I never have liked closed headphones and it is my belief that the soundstage is wider. This is especially evident when I listen to classical music. If I were to listen to the pop music you listen to, then it wouldn't matter what kind of headphones I used as most pop records sound like crap to begin with.

Well, the best way to have a live concert experience is to go to a live concert. Headphone listening is by default "unnatural", but it can be made pretty natural using good phones, crossfeed and low enough output impedance to drive the phones accurately.

A small fraction of my listening is "pop music". I agree with you most pop records sound like (complete) crap, but the best ones can sound spectacular.
Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

chadfeldheimer

Quote from: 71 dB on June 06, 2015, 09:45:26 AM
What exactly are you sceptical about? You haven't demonstrated errors in my calculations (please do so if you find any). What I am speaking about is based on my own experiences with these parallel resistors, my insight of the issue. It takes 2 resistors, a headphone extension cable and 5 minutes with a soldering iron to verify my words.
Thank you for the detailed answer. To keep it short: I'm just a bit sceptical about the fact, that most of the amplifiers output power is used for heating resistors and not to get transformed into soundwaves. Also the Amplifier is optimized for high ohmic phones.

71 dB

Quote from: chadfeldheimer on June 06, 2015, 10:57:25 AM
Thank you for the detailed answer. To keep it short: I'm just a bit sceptical about the fact, that most of the amplifiers output power is used for heating resistors and not to get transformed into soundwaves.

You are welcome.  :)

As long as there is enough power to waste this doesn't matter. Did you know that typical hifi loudspeakers use only 0.1 % of the power to produce sound and the rest 99.9 % goes to heating the voice coils etc.?

In practise "heating resistors" is not that dramatic as you would imagine because the signal levels are rather low on "safe" listening levels. I use 0.6 W precision (1 %) resistors and I can't feel them heating up at all even if I play music insanely loud.

Quote from: chadfeldheimer on June 06, 2015, 10:57:25 AMAlso the Amplifier is optimized for high ohmic phones.

So it seems, at least it should be capble of driving high impedance phones well. I didn't get 100 % clarity of what your problem using HD 595 with it was, but I can say:

- Damping factor criteria is not fulfilled without 12 Ω (or smaller) parallel resistors.
- Frequency response error is 1.3 dB without paraller resistors and 0.7 dB with 12 Ω paraller resistors.
- In case you suffered from amp noise, the parallel resistors would reduce the noise by 4.9 dB

Perhaps my suggestion sounds too cheap and not stylish or cool enough to you? This is not snakeoil. This is rational engineering based on scientific facts. That's why it works.
Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

merlin

Been enjoying the exchange of information very much.  You guys are definitely the experts!

Wondering if there is a commercial crossfeed appliance available for listening to my cd/sacd player through headphones?

BTW, my Bryston BHA-1 claims it has 2 ohms output impedance, so according to what I have been reading on this thread, that should be perfect for my headphones???  Or are there other variable to consider?

71 dB

Quote from: merlin on June 06, 2015, 12:35:13 PM
Been enjoying the exchange of information very much.  You guys are definitely the experts!

Nice! Thanks!

Quote from: merlin on June 06, 2015, 12:35:13 PMWondering if there is a commercial crossfeed appliance available for listening to my cd/sacd player through headphones?

Unfortunately there aren't much such appliances to my knowledge. Some headphone amps have crossfeed, but that's pretty much it. People make their own crossfeeders, which is a fun hobby imo.  :)

Here are nice step-by-step instructions how to make a crossfeeder: http://www.rock-grotto.co.uk/x-feed.htm
Here is another: http://www.instructables.com/id/Cheap-Acoustic-Simulator-Crossfeed-for-Headphone/?ALLSTEPS

Quote from: merlin on June 06, 2015, 12:35:13 PMBTW, my Bryston BHA-1 claims it has 2 ohms output impedance, so according to what I have been reading on this thread, that should be perfect for my headphones???  Or are there other variable to consider?

Your Bryston should drive any phones (sorry, what do you use/have Merlin?) without problems.
Spatial distortion is a serious problem deteriorating headphone listening.
Crossfeeders reduce spatial distortion and make the sound more natural
and less tiresome in headphone listening.

My Sound Cloud page <-- NEW Jan. 2024 "Harpeggiator"

merlin

Thanks for the links, but building one of those is far beyond my skills. :-[

I have been using a very old Sony MDR-V6, and am about to replace it with a Fostex TH900.