Electrostatic Vs Everything Else

Discussion in 'Headphones' started by Rotijon, Oct 6, 2015.

  1. UltraShock

    UltraShock Rando

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    For the record, I was using a SRM-1 MK2 or a Crown D75A paired with a SRD-7 Pro with the Lambda. Obviously the SR-X stems from a very different driver design :)
     
  2. Smitty

    Smitty Too good for bad vodka - Friend

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    I currently have a Woo WEE, but my BHSE is scheduled to arrive sometime late this year. Yggdrasil -> Rag -> Woo WEE -> SR-007a w/Spritzer mod is already a very good setup, it will be fun to see how it improves with a proper stat amp.
     
  3. briskly

    briskly Friend

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    I'm not so sure about that simulation. The notch around 3-4 kHz doesn't show up on your plate measurement or on Tyll's drum simulator measurement. The dip right below 6 kHz does show up on measurement. Still the best sort of headphone porn around.

    Interpreting the IR directly seems unwise. Any shift in the frequency response target makes the neat little burst signals not look like Delta functions anymore. Tyll's got an ear simulator, and it doesn't look like he applies correction onto the impulse for the filtering performed by the artificial ear. The headphones with the neatest IR tend to measure closer to flat at drum equivalent, with a minimum of peaking.

    http://www.innerfidelity.com/images/MrSpeakersMadDog2014.pdf
    http://www.innerfidelity.com/images/VSonicGR07.pdf
    http://www.innerfidelity.com/images/OppoPM1VelourPads.pdf
    http://www.innerfidelity.com/images/StaxSR007SZ31576.pdf

    I do realize the last is the electrostatic 007, but that mostly looks off because it has a peak in the upper treble, most of the spectrum is otherwise unequalized.
    Arnaud did some of that filtering on the square waves and impulse back at CS. On the 009, the adjustment makes the square waves look more square, and the IR settle a bit faster. Note the scale is not the same as Tyll's.[​IMG]
    http://www.changstar.com/index.php/topic,496.msg8527.html#msg8527
     
  4. ultrabike

    ultrabike Measurbator - Admin

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    I think Arnaud was working on ear pads and showing that it should be expected that different ear pads would exhibit different notch behavior. However, the point was not that there was such a notch-pad dependency. The point was that one is likely not going to get a nice smooth frequency independent "planar" wavefront in a headphone. Stat or no stat.

    Interpreting the IR directly from a set of measurements that apply compensation to the frequency is probably not ideal. I could say the exact same think about square waves.

    That said, some of our measurements here are not compensated. So the impulse response and the square waves are in agreement with the frequency response. I might be able to check the impulse response of my measurements...

    AFAIK compensation is bandlimited and can't do much to make things "faster". In fact, the compensated square waves by Arnaud IMO are not settling "faster". The difference is that the system went from overdamped to underdamped after compensation.
     
  5. briskly

    briskly Friend

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    Ah, crap. I realized right after I posted that is not 009. The variation still shows up in the bass and midrange depending on the earpad. And yeah, the planar wave doesn't seem to apply here with the uneven pressurization, I think.

    If you are only ever feeding it a noticeably bandlimited signal like music, which usually does not have strong signals above 10kHz, how fast does it need to be? And yeah, left channel of compensated 009 is more heavily damped as such, with the sloping DF/ID frequency corrected plot, but the IR does actually cross the zero line.
     
  6. ultrabike

    ultrabike Measurbator - Admin

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    Yes. after compensation things become fairly underdamped.

    I do have somewhat decent 009 measurements along with a lot of other measurements. Maybe even an HD800 and a bunch of HD600 like stuffs. If I can get access to the raw impulse response I could plot them. These would be from uncompensated measurements.

    As far as bandwidth, note that the mic will also roll off at some point. Most audio equipment is supposed to do pretty good in the audio frequency range, but not so hot in certain ultrasonic ranges. Which IMO really doesn't matter. I think when folks are talking about "speed" in a subjective context they are more than likely referring to a particular sound signature. Not how fast the diaphragm stops which start to turn into an ultrasonics discussion.
     
  7. UltraShock

    UltraShock Rando

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    I agree regaring "speed" when talking about sound signatures. It's definitely worth taking a given mic's frequency response into consideration when doing these as well!
     
  8. ultrabike

    ultrabike Measurbator - Admin

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    Measurement grade mics should be relatively flat (relative to what headphones do) in the audio range. I know there is all these talk about having to compensate your mic or else everything you do is shit. However, I don't think things are that far of in general from bass to upper mids.

    Compensating the mic will have a similar impact on the measurements as compensating for ear simulator. Though much smaller. Again, unless the mic is broken or something, usually the headphone may exhibit more variation than the mic itself. From what I've seen at least.

    Mics are bandlimited though. Very expensive ones probably less so, but still band limited.
     
  9. UltraShock

    UltraShock Rando

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    I agree entirely - you pretty much said everything I was hoping to imply.
    I was just hoping nobody is using like, vocal condenser mics to make measurements ;)
     
  10. ultrabike

    ultrabike Measurbator - Admin

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    LOL! I think the majority of measurement mics are omni-directional electret condenser mics. Which I think are also called electrostatic microphones. I think this is an area where electorstatic audio stuff has become main stream, and sort of cheap.

    Bias voltage I think is more like 48V though. Not 600 something hairy volts.
     
  11. briskly

    briskly Friend

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    Underdamped? The adjusted square wave rings much less after compensation, not something removing damping from an oscillator does.

    To get closer back to the topic, I preferred the 009 over the other Stax, but I still thought it sounded like a bottle of bleach: clean, lifeless, and without energy. Now I happens to also think that the 009 doesn't have enough general treble, and that my HD 600 has more treble energy and presence,
     
  12. ultrabike

    ultrabike Measurbator - Admin

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  13. briskly

    briskly Friend

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    The "before" was applying frequency correction to the square wave directly by mistake, takes out the upper frequencies that would give you the corners. You see something like that with the corrected Audezes which are closer to flat at drum, the square wave is overdamped, particularly to DF.

    [​IMG]
     
  14. ultrabike

    ultrabike Measurbator - Admin

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    I think I better understand what's going on. The problem is that the compensation had to be inverted before it could be applied.

    The correction is a subtraction. But in dB. So it's a division. One would have to invert the correction to make it a multiplication. Then one would take the IFFT of the inverted correction and convolve it directly with the square wave to get the compensated results.

    Anyhow, here are the impulse responses, from top to bottom for the SR009, HD600, and HD800:

    Impulse_SR009_HD600_HD800.png

    The impulse responses do not need compensation to reflect on the frequency response previously reported, since the frequency response reported was not compensated. I could smooth out the curves (equivalent to valid interpolation), but I'm kind of tired right now. Long day.

    To obtain square waves one could just convolve an ideal square wave with the above IR.
     
    Last edited: Nov 10, 2015
  15. Rotijon

    Rotijon Friend

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    Was the spritzer mod particularly tricky to implement? Im thinking of doing that but am abit apprehensive of opening them up.
     
  16. Smitty

    Smitty Too good for bad vodka - Friend

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    I bought mine already modded, but it's not that hard. The official directions can be found here: link

    Boils down to take out the screws holding the cup together, apply bluetack, reassemble.
     
  17. Rotijon

    Rotijon Friend

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    This is probably a very dumb question, and im hoping a knowledgeable builder can answer. This is coming from the perspective of a complete newb and noob.

    What is it about Electrostatic Amps especially the KG ones that makes them so damn expensive. Looking at the BOM cost, it does not seem far off when compared to the nice dynamic/ortho amps.

    The assembly does not look too difficult, at least when i open up the case and look.

    And yet they are easily double or triple the prices of equivalent dynamic amps. Lets not even look at the T2/BHSE/Nanotube types.
     
    Last edited: Dec 28, 2015
  18. shipsupt

    shipsupt Admin

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    So which Gilmore amp are you talking about? From which builder? Prices vary for different reasons... We need a little more of a specific example to respond.
     
  19. Rotijon

    Rotijon Friend

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    Just in general. The ones for sale at least.

    I get that different builders use different parts and thus have different price range, but on average electrostatic amps just seem to be a level above in price.

    A normal T2 or Circlotron will set you back at least 12-15k and this is using normal parts and not those exp riken, black gate etc.

    The most prominent one for me now is the kgsshv Carbon. People are quoting 4K plus to birgir's 4.6k and looking at the board, they don't look 4.6k to me. I mean it's really like 4 boards plus a torodial in a box.

    Though to be fair, birgir said that his parts cost 30-40% more due to taxes in his country.

    And since the schematics are free, I don't think we're paying for rnd either.

    Are people just charging using mjolnir audio and normal electrostatic amp prices as a benchmark or is there some expensive as hell component or process I'm missing?
     
  20. shipsupt

    shipsupt Admin

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    There's no unobtainium in the new amps as far as I know, so the cost is a combination of the actual parts cost, some cost for the labor, and a little mark up for profit. The amount of profit that can be added is driven by the market, but you certainly can't ask these guys to build for "cost".

    Most the builders I'm aware of building good Gimore designs are not making a killing, and most dump the "profit" into prototyping whatever the next latest and greatest is. Go ahead and grab the BOM and total up the parts cost; the information is openly available. Then you can decide if the difference of what they are charging is worth their time, experience, and getting a realible amp delivered.

    Having built several KGSShv's while living in Europe I can second Birgir's comments on taxes, figure 20-40% higher for parts cost vs. the USA. Many would say these are simple amps, but hard cost can clear $2000 easily depending on the parts selected, shipping cost of seperate components, choice of chassis and attenuator. That's not incuding any labor cost.

    I support the guys who do quality builds to get paid a little for doing good work. I don't like seeing some flippers selling off builds they baught for more than they paid just because the market will support it... but hey, it's a free market, right?

    The beauty is that the designs are readily available for free along with great internet support. If you want to build it as cheap as it can be done, the best way is to grab a iron and DIY! It's very rewarding.
     

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