Head-Fi.org › Forums › Equipment Forums › Sound Science › A basic question about measurements on headphones
New Posts  All Forums:Forum Nav:

A basic question about measurements on headphones

post #1 of 15
Thread Starter 

Hello !

 

I have some questions on headphones.

  1. I understand that they are particular type of "speakers", but for the loudspeakers drivers a full set of parameters are available.  For the drivers in HP nothing ... why ?  do not they have resonance freq, qts, impedance, ecc. ecc. as well ?
  2. I assume that the driver of an HP is a complex load, not purely resistive at all.  So why test HP amplifiers on purely resistive loads ?
  3. Most of the review are based on subjective listening tests.  Is this the only way to assess the performance of an HP ?I am a fan of instrumental tests so you can understand my confusion.  In particular i am convinced that some very important qualities of HPs like the so called "transparency" or the "innear detail" could be highlighted by the suitable instrumental test.
  4. I have seen in the web only graph like the following

 

 

is the freq response the only measurement of some value for HPs ??? (of course better than nothing, that is clear, but ... )

 

To conclude the ramblings, could measurements be useful to assess the quality of an headphone or an HP amp ?

Then I think that the amps should be tested with "real" loads and headphones with reference amps able to drive them properly.

Thank you very much for any advice.

Kind regards,

gino


Edited by ginetto61 - 3/29/13 at 2:16pm
post #2 of 15

1) Look at impedance plots. They show you the resonant frequency (peak usually roughly around 100 Hz).

2) Some amplifier measurements use real headphones as load. But I guess it's more convenient to use a resistor to for example test max output power.

3) Every person has a differently shaped head, outer ear, ear canal ... so you should always take a listen yourself before buying a headphone. Dummy head measurements give us a good idea of how the headphone sounds though.

 

For more detailed measurements go to build a graph or innerfidelity.

 

Yeah, I'd argue frequency response is the most important measurement.


Edited by xnor - 3/29/13 at 2:44pm
post #3 of 15
Thread Starter 

Thank you very much indeed for your kind and valuable reply.

I have just another question on drivers' parameters.

For a loudspeaker driver it is possible to measure the Qts.  This is a very telling parameter for me because it puts together, trivially speaking, the mass of the driver and the power of the magnet.

The lower the Qts the higher the "driving" power in relation to the mass of the driver.  It is something like the ratio weight/ horse power in cars.

I do not know if a Qts can also be determined for headphone drivers but I have noticed an important particular.

If we look at the the top of the line HPs we can see very big and probably powerful magnets and I think this is very good and sign of higher quality

 

This should be in some way reflected in some measurements.

Thank you very much for the links

I go to study

Kind regards,

gino

post #4 of 15

1. Speaker and Headphone manufacturers rarely provide driver parameters. Speaker and Headphone driver manufacturers probably do. Note that there are also probably more speaker driver direct vendors than headphone driver direct vendors. However, these might work for headphones (but not sure):

 

http://www.digikey.com/product-detail/en/CLF0381MP-1/102-1549-ND/1630863

http://www.digikey.com/product-detail/en/GF0401M/GF0401M-ND/304449

 

It is possible that some, if not most, headphone companies probably develop their drivers in house and do not offer them (or their parameters) to the public to develop their own headphones.

 

2. Some headphones (planar magnetic) do offer an almost purely resistive load. Some dynamic ones are probably better modeled as 3rd order RLC circuits (http://home.comcast.net/~tamivox/dave/speaker/graphs.html), but in some cases they may still be mostly resistive. As a side note, my understanding is that electrostats are almost purely capacitive (80 to 150 pF.) Like xnor said, some amps are characterized with headphone loads. Note however that headphone loads are all over the map even if we restrict ourselves to dynamic, BA, and planar magnetic. It is therefore difficult to arrive at a "typical" load that will suit every case. To simplify this problem, most amp manufacturers target low output impedances for their amp designs.

 

3. Subjective test are IMO VERY IMPORTANT when honest and from experienced individuals, and most importantly from yourself. But FR, CSD, THD, IMD, sensitivity, impedance, and so forth are available for different headphones . Manufacturers of both headphones and speakers rarely furnish this information. Again, I'm making a distinction between speaker manufacturers, and speaker driver manufacturers.

 

If the goal of a high fidelity transducer is to be as linear as possible (to not introduce frequencies not originally contained in the source equipment,) then I agree with xnor that FR is probably the most important measurement. Finer details can probably be accessed through CSDs, THD/IMD/HD. Sensitivity and impedance might be useful to figure out proper amp driving requirements...

 

Hope this thoughts help.


Edited by ultrabike - 3/30/13 at 3:03am
post #5 of 15
Quote:
Originally Posted by ginetto61 View Post

Thank you very much indeed for your kind and valuable reply.

I have just another question on drivers' parameters.

For a loudspeaker driver it is possible to measure the Qts.  This is a very telling parameter for me because it puts together, trivially speaking, the mass of the driver and the power of the magnet.

The lower the Qts the higher the "driving" power in relation to the mass of the driver.  It is something like the ratio weight/ horse power in cars.

I do not know if a Qts can also be determined for headphone drivers but I have noticed an important particular.

If we look at the the top of the line HPs we can see very big and probably powerful magnets and I think this is very good and sign of higher quality

 

This should be in some way reflected in some measurements.

Thank you very much for the links

I go to study

Kind regards,

gino

 

That is probably a way kool Tesla frisbee... Not very high marks in Qts AFAIK:

 

Impedance to Qts: http://www.wavecor.com/Measuring_driver_Q-values.pdf

Check Beyer Tesla T1 impedance plot here: http://www.innerfidelity.com/images/BeyerdynamicT1.pdf

 

So, for the whole headphone I get the following from the above links... No guarantees here...

Re = 600 ohm

Fs = 100 Hz

Zmax = 1400 ohm

Z0 = sqrt(Re*Zmax) = 917 ohms

F1 = 30 Hz

F2 = 300 Hz

 

Therefore

Qms = 0.566

Qes = 0.424

Qts = 0.24

 

A bit over-damped in speaker world I think (0.5 Qts seems to correspond to critically damped while 0.707 seems to correspond to "maximally flat" blink.gif according to this dood: http://www.avsforum.com/t/1294235/infinite-baffle-subs-some-low-power-small-motor-some-higher-power-larger-motor#post_19574053)

 

If I go by the HD600 numbers (http://www.innerfidelity.com/images/SennheiserHD600.pdf):

Re = 300 ohm

Fs = 100 Hz

Zmax = 550 ohm

Z0 = 406 ohm

F1 = 40 Hz

F2 = 200 Hz

 

Therefore

Qms = 0.85

Qes = 1.01

Qts = 0.46

 

Still over-damped, but closer to critically damped.

 

In any case, I still feel FR should display most of the actual linear behavior of the headphone better.

 

These two headphones are open so probably somewhat low enclosure damping exists.


Edited by ultrabike - 3/30/13 at 3:47am
post #6 of 15
Thread Starter 

Hi to Everyone and thank you very much indeed for the very valuable input.

Of course freq response is absolutely fundamental. No doubts about that.

Maybe it is just me that i am obsessed with graphs and  figures.

But also i think engineers at Beyerdynamic and Sennheiser must be very obsessed. And in the end they design the units.

For instance, i was looking at the Inner fidelity distortion graphs.

I imagine that they have been obtained with a same reference amp, that anyway could be not optimized for low and high impedance HPs at the same level.

HPs are much more different one to another than speakers.  The impedance varies from 30 to 600 ohm ... this is a huge range indeed.

I think it is difficult to evaluate a Grado and a Senheiser with the same amp.

A high output impedance tube amp can have low control on the Grado and instead sound spectacular with 300 to 600 ohm HPs.

It is a very complex task.

Nevertheless I believe in tests, and FR and distortion tests but also square wave test would be valuable (with the amp also tested together with the HPs).

Speaking of Qts it would be interesting to see a list of the values of different drivers.

For me the lower the Qts the better, always.

So when a see huge magnets i think it is a good thing (and usually are on more expensive units).

When I see people speaking of a dry bass I would call it control.  And the sound without control is just ... out of control actually.

Thanks a lot again for the helpful advice.

kind regards,

gino
 

post #7 of 15
Quote:
Originally Posted by ginetto61 View Post

I imagine that they have been obtained with a same reference amp, that anyway could be not optimized for low and high impedance HPs at the same level.

HPs are much more different one to another than speakers.  The impedance varies from 30 to 600 ohm ... this is a huge range indeed.

I think it is difficult to evaluate a Grado and a Senheiser with the same amp.

A high output impedance tube amp can have low control on the Grado and instead sound spectacular with 300 to 600 ohm HPs.

If the amp can drive low impedance HPs and has a high gain switch it is equally suitable for low and high impedance HPs.

A low output impedance amp works well with most headphones and is important for the measurements.

 

 

Quote:
Speaking of Qts it would be interesting to see a list of the values of different drivers.

For me the lower the Qts the better, always.

Qts is the total Q of the speaker only, but the calculations above are based on the "speaker" in its "enclosure". This is not to be confused with Qtc (total Q of the speaker in an enclosure including all system resistances).

 

For example Fs above should be the resonant frequency in free air. For loudspeaker measurements Rod Elliot writes:

Quote:
Any boundary closer than around 600mm (about 2ft) will affect the accuracy of the measurements

So the accuracy of above measurements is probably very low.

 

 

Anyway, using the formula above you are even "better" off with a 32 ohm DT880 and you also save over € 600. redface.gif


Edited by xnor - 3/30/13 at 7:33am
post #8 of 15
Quote:
Originally Posted by xnor View Post

If the amp can drive low impedance HPs and has a high gain switch it is equally suitable for low and high impedance HPs.

A low output impedance amp works well with most headphones and is important for the measurements.

 

Yes. As long as it can provide enough current and voltage to the load, and if the amp is not to compensate for any headphone FR aberrations (which a dedicated eq might do a better job at.)

 

Quote:
Originally Posted by xnor View Post

Qts is the total Q of the speaker only, but the calculations above are based on the "speaker" in its "enclosure". This is not to be confused with Qtc (total Q of the speaker in an enclosure including all system resistances).

 

For example Fs above should be the resonant frequency in free air. For loudspeaker measurements Rod Elliot writes:

So the accuracy of above measurements is probably very low.

 

 

Anyway, using the formula above you are even "better" off with a 32 ohm DT880 and you also save over € 600. redface.gif

 

Yes. It was a best effort deal there with the available information, if Qts info is a must.... Dunno if Tyll measured impedance with headphones coupled to the dummy head either. If not maybe the calculations are not too bad (but honestly not sure.) A measurement of impedance with the driver outside the enclosure would likely have to be made and compare results... 

 

I also think that a DT880 is a better phone than a T1, and an HD600 a better can than both. Performance is not just a function of the driver magnets. This is why I think Qtc might be a better metric (which I agree is not what I did there)... And headphone frequency response magnitude (+ CSDs to visualize some phase information) probably even better...


Edited by ultrabike - 3/30/13 at 1:04pm
post #9 of 15
Thread Starter 
Quote:

Originally Posted by xnor View Post

If the amp can drive low impedance HPs and has a high gain switch it is equally suitable for low and high impedance HPs.

A low output impedance amp works well with most headphones and is important for the measurements.

 

Thank you again ! I like very much this approach that allows the customer to choose his/her favourite HP.

 

 

Qts is the total Q of the speaker only, but the calculations above are based on the "speaker" in its "enclosure".

This is not to be confused with Qtc (total Q of the speaker in an enclosure including all system resistances).

For example Fs above should be the resonant frequency in free air. For loudspeaker measurements Rod Elliot writes:

So the accuracy of above measurements is probably very low.

 

I am pretty sure that the Qts is specific of the driver, the transducer alone.

and actually it is found among the other transducer parameters

This of course does not take into account the enclosure

Usually for loudspeaker transducers the lower the Qts the higher the quality and the price

 

Anyway, using the formula above you are even "better" off with a 32 ohm DT880 and you also save over € 600. redface.gif

 

I do not understand if you are speaking of the Qts or the Qtc (?). 

and this is for me a huge surprise because i was pretty sure that the more expensive HPs have also the better transducers.

And the better the transducer should mean the better sound (with a same amp at least)

I believe transducers are the key

i do not think that Sennheiser has design the new transducer for the HD800 just for a marketing purpose, maybe i am wrong ?

 

 

Looking at the transducer of the T1 it looks really impressive as well. I have not seen that one in the DT880 anyway

I would be surprise that the transducer in the dt880 would perform better.  Also from a commercial point of view this does not make sense.

I think tha the T1 is the better headphone in the end.  Maybe it needs the right amp to fly.

Of all the tests, after the freq response test, I would like to test more the distortion characteristics of the HPs.

Like original test procedure ad so on.

Anyway thank you very much indeed.

Kind regards,

gino

 

 

 

 


Edited by ginetto61 - 3/31/13 at 2:44am
post #10 of 15
Quote:
Originally Posted by ginetto61 View Post

Looking at the transducer of the T1 it looks really impressive as well. I have not seen that one in the DT880 anyway

I would be surprise that the transducer in the dt880 would perform better.  Also from a commercial point of view this does not make sense.

I think tha the T1 is the better headphone in the end.  Maybe it needs the right amp to fly.

 

Well, it is not the only overpriced and underperforming "flagship" headphone released recently. If you compare the measurements, the results are rather mixed. The DT880 has a much cleaner impulse response and CSD, and it also has lower and more consistent distortion (except with loud bass, which is a weak point of the DT series); it also seems to be less prone to weird QC issues (wildly varying FR measurements, channel imbalance, huge distortion peaks at random frequencies, etc.). On the other hand, the T1 is more efficient, can handle higher power and SPL, distorts less with loud bass, and may have a better sound stage because of the angled drivers. But it is not very impressive at four times the price.


Edited by stv014 - 3/31/13 at 4:15am
post #11 of 15
Thread Starter 
Quote:
Originally Posted by stv014 View Post

 

Well, it is not the only overpriced and underperforming "flagship" headphone released recently. If you compare the measurements, the results are rather mixed.

The DT880 has a much cleaner impulse response and CSD, and it also has lower and more consistent distortion (except with loud bass, which is a weak point of the DT series); it also seems to be less prone to weird QC issues (wildly varying FR measurements, channel imbalance, huge distortion peaks at random frequencies, etc.).

On the other hand, the T1 is more efficient, can handle higher power and SPL, distorts less with loud bass, and may have a better sound stage because of the angled drivers. But it is not very impressive at four times the price.

 

Thanks a lot for the interesting and valuable advice.  Now this is surprising but also very intriguing.

Maybe a good headphone must not be extremely expensive

Presently I have just low to mid quality units:

  • Beyer dt990 250 ohm,
  • Akg K242 and an old k280,
  • JVC 900,
  • Grado sr200, and
  • some cheap low impedance HPs.

i am listening with a Fiio e9 now but I am thinking to a better amp (I would be set on the Schiit Asgard 2 but the heat and the hum from the transformer concern me)

I think that the Beyer should be best of the lot but comparison tests are just at the beginning

I would be grateful if you could give me your opinion.

of course i am looking only for a nice result and not fatiguing results.  I am listening also to movie on headphone so reproduction of voices is of extreme importance to me.

Thanks a lot again

Kind regards,

gino


Edited by ginetto61 - 3/31/13 at 5:33am
post #12 of 15

The more I think about it, the more I believe my Qts exercise there was futile... I learned something so it was probably not all for nothing biggrin.gif

 

All these Q-things (Qts, Qc, Qtips, and so forth) should all be already lumped into the overall SPL impulse response measurement of a headphone. All those parameters are probably more useful in speaker development than in headphone characterization. From the impulse response (+ possibly some compensation due to HRTF or so) one can derive FR magnitude/phase, CSD, step response, square wave thingys, and other stuff. If a headphone performs poorly in SPL FR and distortion measurements, it more than likely will suck regardless of price.

 

I actually used to own the DT990 250 ohms, and felt it was quite a bit bright. No channel imbalances, no huge distortion issues, or wild frequency peaks though. Just too much energy in the tremble region that resulted in some fatigue after a while (it's fine if equalized though.) So I went for some HD558 which I ended up liking quite a bit more.

 

There are some very good, but expensive headphones though. Stax 007/009 electrostatic headphones tend to perform very good in distortion numbers. HD800 headphones also seem to do very good in distortion numbers relative to other dynamic headphones. I don't feel that their transducer technology is all just marketing mumble jumbo. Note however that ring radiators are not exactly a new thing. Just probably not as applied to headphones as other types of transducers. The Stax and the HD800 also seem to have fairly good SPL FR performance numbers. Stax headphones however have specific amplification requirements. HD800 might be driven by more conventional amps, but they still have relatively high impedance numbers. None of these headphones are portable.

 

Has far as the Asgard having hum problems, my understanding is that this could be due to ground loop problems. Schiit recommends to use a 3 to 2 prong adapter in such cases (http://schiit.com/ownersmanual/asgard_manual_1.0.pdf). As far as heat, well it seems this amp is class A. A Schiit Magni is class AB and might be cooler (http://schiit.com/cart/index.php?main_page=product_info&cPath=0&products_id=13).


Edited by ultrabike - 3/31/13 at 3:44pm
post #13 of 15
Thread Starter 
Quote:

Originally Posted by ultrabike View Post

The more I think about it, the more I believe my Qts exercise there was futile... I learned something so it was probably not all for nothing biggrin.gif

All these Q-things (Qts, Qc, Qtips, and so forth) should all be already lumped into the overall SPL impulse response measurement of a headphone. All those parameters are probably more useful in speaker development than in headphone characterization. From the impulse response (+ possibly some compensation due to HRTF or so) one can derive FR magnitude/phase, CSD, step response, square wave thingys, and other stuff.

If a headphone performs poorly in SPL FR and distortion measurements, it more than likely will suck regardless of price.

 

Hello ! actually you are perfectly right.  We can treat the HP as a black box and just see its test performances.

I would add the square wave test to the list even if as many say it is not a "natural" signal

Nevertheless it is a very demanding test that can tell something about the dynamic behaviour of the driver

I have never seen, for instance, the response to SW of a Stax. I am pretty sure it should be just amazing

What is intriguing is that also cheap headphone can have nice results in the lab, and i suspect also at the listening.

The problem is to spot them but i have to read a lot this forum because something very interesting often shows up.

 

I actually used to own the DT990 250 ohms, and felt it was quite a bit bright.

No channel imbalances, no huge distortion issues, or wild frequency peaks though.

Just too much energy in the tremble region that resulted in some fatigue after a while (it's fine if equalized though.)

 

I have just start using them with a Fiio e9.  They are well built, robust

i think the break-in will take a while 

I do not like the felt over the transducer

For me the Grado solution is hugely better and i suspect it improves the transparency

Problem is that i would not want to damage the Beyer but i will try to remove the felt ... maybe i will get even more highs but i am sure the sound will improve

Every layer between the transducer and the ear decreases transparency

I tested this on two cheap JVC and one AKG.  Always better sound

 

So I went for some HD558 which I ended up liking quite a bit more.

 

I like Senn very much.  They are controlled and clean

To add some warm it is possible to select the right amp, or maybe even a solid core cable as a extension cord can work.

 

There are some very good, but expensive headphones though.

Stax 007/009 electrostatic headphones tend to perform very good in distortion numbers.

HD800 headphones also seem to do very good in distortion numbers relative to other dynamic headphones. I don't feel that their transducer technology is all just marketing mumble jumbo. Note however that ring radiators are not exactly a new thing. Just probably not as applied to headphones as other types of transducers.

The Stax and the HD800 also seem to have fairly good SPL FR performance numbers. Stax headphones however have specific amplification requirements. HD800 might be driven by more conventional amps, but they still have relatively high impedance numbers. None of these headphones are portable.

 

You are talking about the very top HPs.  I listen to the Stax and it is a very different experience

They were the Omega do not the number.  Initially they seem lean and a little bright

But then it is easy to understand that it is just that the distortion is very very low.

I did not try the HD800.  Too expensive for me anyway, but extremely attracting.

 

Has far as the Asgard having hum problems, my understanding is that this could be due to ground loop problems.

Schiit recommends to use a 3 to 2 prong adapter in such cases (http://schiit.com/ownersmanual/asgard_manual_1.0.pdf).

As far as heat, well it seems this amp is class A.

 

I am very very interested in the Asgard 2 and i have the opportunity to buy one

What i read it is confusing at least.  Spectacular sound but also remarkable problems

I understand that it is better with 100-300 ohm HPs, so it should be work fine with the dt990 250 ohm

 

A Schiit Magni is class AB and might be cooler (http://schiit.com/cart/index.php?main_page=product_info&cPath=0&products_id=13).

 

This is also very very interesting. And it could be the best choice for me (i am not looking for extreme performance just a good rendition of voices because i have to follow dialogues in English during movies and tv serials.  Yes, I am trying to improve my level.  Not that easy I am afraid.) 

i will wait a little and read further reviews expecially on the Magni

Thank you sincerely again for your kind and very valuable advice

My best regards,

gino

 

 

 

 

 

 

 

 

 

 

 

 

 

post #14 of 15

Here are some Stax square waveys biggrin.gif:

 

http://www.innerfidelity.com/images/StaxSR009.pdf

http://www.innerfidelity.com/images/StaxSR404LtdSSL0670.pdf

http://www.innerfidelity.com/images/StaxSR507SE11049.pdf

http://www.innerfidelity.com/images/StaxSR007.pdf

http://www.innerfidelity.com/images/StaxLambdaSBsnA19858.pdf

 

... Not so good one here:

 

http://www.innerfidelity.com/images/StaxSRSigma07381.pdf

 

The TOTL latest models typically exhibit low distortion, but their FR is definitively not perfect. An equalizer can be used to good results with them since an equalizer can fix moderate FR issues as long as non-linear distortion is not fugly (same could be said about the HD-800.)

 

As far as square waves, they can only excite the headphone through their fundamental, and their odd harmonics. An impulse is a more powerful signal for linear system characterization purposes (what a headphone should strive to be.)

 

A square wave response results in a steady state signal, and should not be confused with the step response (transient signal.) The step resoponse is basically the running integral of the impulse response. The step response is sometimes used to check damping stuff, but I guess one can best approach a step with a long period square wave (large enough period to allow the headphone to come to complete "rest".) Anyhow, integration of the impulse response yields the step response anyway. Furthermore, convolving a square wave with the impulse response yields square wave results if such are desired. So... impulse response (and/or its Fourier Transform also known as the Frequency Response) is a good thing to have.

 

As far as cables is concerned, I don't concern myself too much with them. If you want to tame some FR issue, might as well dive down to equalizer territory.

 

BTW, the Schiit Asgard 2 is supposed to have < 2 ohms of output impedance:

http://schiit.com/cart/index.php?main_page=product_info&cPath=0&products_id=16

So it should play nice with most headphones north of 16 ohms.

 

The Schiit Magni is advertised to have an output impedance < 0.1:

http://schiit.com/cart/index.php?main_page=product_info&cPath=0&products_id=13

Which if true should make it compatible with even the most demanding IEMs...

 

Not shilling products here, just letting you know that Schiit does seem to have a fairy good reputation...


Edited by ultrabike - 4/1/13 at 3:26am
post #15 of 15
Thread Starter 
Quote:

Originally Posted by ultrabike View Post
Here are some Stax square waveys biggrin.gif:

http://www.innerfidelity.com/images/StaxSR009.pdf

http://www.innerfidelity.com/images/StaxSR404LtdSSL0670.pdf

http://www.innerfidelity.com/images/StaxSR507SE11049.pdf

http://www.innerfidelity.com/images/StaxSR007.pdf

http://www.innerfidelity.com/images/StaxLambdaSBsnA19858.pdf

 

Hello and thank you very much indeed

i am not an expert but the graphs look very good indeed

Strange that often distortion is lower at 100dB compared to 90dB ... rolleyes.gif

By the way at least for some models is very low indeed.  eek.gif  Good thing i suppose

 

... Not so good one here:

http://www.innerfidelity.com/images/StaxSRSigma07381.pdf

The TOTL latest models typically exhibit low distortion, but their FR is definitively not perfect.

An equalizer can be used to good results with them since an equalizer can fix moderate FR issues as long as non-linear distortion is not fugly (same could be said about the HD-800.)

 

Interesting option indeed.  As I usually listen through a windows PC i wonder if there are any Equalizer software. But i think a mic is also needed to see peaks and holes in the FR

But very interesting indeed.

 

As far as square waves, they can only excite the headphone through their fundamental, and their odd harmonics.

An impulse is a more powerful signal for linear system characterization purposes (what a headphone should strive to be.)

A square wave response results in a steady state signal, and should not be confused with the step response (transient signal.)

The step resoponse is basically the running integral of the impulse response. The step response is sometimes used to check damping stuff, but I guess one can best approach a step with a long period square wave (large enough period to allow the headphone to come to complete "rest".)

Anyhow, integration of the impulse response yields the step response anyway.

Furthermore, convolving a square wave with the impulse response yields square wave results if such are desired.

So... impulse response (and/or its Fourier Transform also known as the Frequency Response) is a good thing to have.

 

this is also extremely interesting but too difficult for me to understand.

I understand that the "ripple" in the impulse test should be limited.  The damping should be high

 

As far as cables is concerned, I don't concern myself too much with them.

If you want to tame some FR issue, might as well dive down to equalizer territory.

 

I see.  Let's cable out of the discussion then.

 

BTW, the Schiit Asgard 2 is supposed to have < 2 ohms of output impedance:

http://schiit.com/cart/index.php?main_page=product_info&cPath=0&products_id=16

So it should play nice with most headphones north of 16 ohms.

 

I see. But i read some comments about problems with low impedance HPs.  Maybe the noise is an electric issue.

The all lot of comments are very disorienting.  Some extremely positive actually

For instance if the Company says that a power cord without ground tames the grounding issue why not provide one with the unit ?

Maybe this could solve the hum issue i read about

The hot is unavoidable for the class A operation.  Take it or leave it.

But if the sound is very good i think that once solved the hum/noise problem the doubts will vanish.

 

The Schiit Magni is advertised to have an output impedance < 0.1:

http://schiit.com/cart/index.php?main_page=product_info&cPath=0&products_id=13

Which if true should make it compatible with even the most demanding IEMs...

 

this is a very interesting product but difficult to buy in Europe I think

At its price it is a bargain i guess. 

 

Not shilling products here, just letting you know that Schiit does seem to have a fairy good reputation...

 

Actually i read very positive comments on the sound of all these units.  So the design is basically very good indeed.

They are really under the radar for an upgrade of my system

I have to check the Magni better rolleyes.gif

Thanks a lot and kind regards,

ginoregular_smile%20.gif

 

 

 

 

 

 

 

 

 


Edited by ginetto61 - 4/1/13 at 10:54am
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Sound Science
Head-Fi.org › Forums › Equipment Forums › Sound Science › A basic question about measurements on headphones