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  1. mikeaj

    The Beyerdynamic DT880 Discussion thread

    Okay, so I have a question about the headband adjustment mechanism. On one side, it's become very loose and the system essentially doesn't grip onto the dots very well, sliding up and down too easily and often by accident.   Anybody had this happen or have any ideas on how to fix it? I figure...
  2. mikeaj

    An interesting page with the mathematics of Sampling

    The mathematics are covered in a DSP course and are clear and unambiguous.   This is the result with that perfect sinc (brickwall) filter. Keep in mind that the sinc filter has infinite support and is non-causal. The correct output now depends on values potentially infinitely in the future...
  3. mikeaj

    FiiO E11K &A3 Portable Amplifier Info/News Thread (Early Impressions)

    Sorry, I tried searching but didn't readily find the answers I was seeking, and I figure some of you may have a better perspective anyway. It's been a while and I'm out of the loop. Thanks.     Anybody know Can the E11K be used while charging? My understanding and recollection was that the...
  4. mikeaj

    Headphone frequency response - amplifier behavior question

    More likely a measurement artifact than anything else. How many runs for each source did you do?   I mean, you can also measure the electrical output of the amp while it is driving those headphones.
  5. mikeaj

    Fulla (by) Schiit - News, photos, thoughts, impressions, etc.

    So what's the channel tracking like? Technically this is the type of thing that wouldn't be that hard to get a decent ballpark estimate on via loopback testing via an audio editor or actually I think even the RMAA calibration, but a general impression is fine too. Any noticeable problems in...
  6. mikeaj

    Synergistic Research HOT device

      For methodological purposes, how about four tracks? Two with HOT and two without. That way there's repeatability and we can see if something in the test changes between two runs.   Or make it a ABXY by labeling A as with HOT, B as without, and X and Y being unknown, so people can try to...
  7. mikeaj

    What is headphone max output (mW)?

      The E17 is not capable of anything close to 1 W (1000 mW) output, so you couldn't have put that much into the headphones. The amount depends on the headphone impedance, volume setting, input level, etc., but suffice to say, it was not near the limit, whatever physically that really...
  8. mikeaj

    Some HOT Science From Synergistic Research

    I mean, seriously, if you designed and oversaw manufacturing of a great new product (much less one never been conceived before) and saw skeptics maligning it, wouldn't you explain how it works and part of the process? I mean, you would have to keep certain details under wraps, but resorting to...
  9. mikeaj

    limits of usb powered DAC/Amps ???

      Audio is not moving very quickly. If you look at where most of the money and engineering talent goes, it's not there (and most of it into the chipmakers, people doing the mass-market stuff). Recent technological breakthroughs don't really have much impact on what you can do with regards to...
  10. mikeaj

    Are there any benefits to SNR higher than 110 dB?

      Just in case this was a real question (at least in the first part), pink noise is a technical term for a specific type of noise, the kind having equal energy in every octave. So equal energy between 20 and 40 Hz as between 40 and 80 Hz and so on. This is as opposed to white noise (equal...
  11. mikeaj

    Confused about power output

    Listed specs may not be completely honest or really listed in ways that are completely comparable, but that's likely not the most relevant issue here.   The thing to realize is that these are maximum levels possible by the electronics. The vast majority of people on most of these devices on...
  12. mikeaj

    IEM FR vs Full size

    I don't know if I'd trust HeadRoom over design engineers at a manufacturer with respect to compensation curves for different headphone types.   IIRC it was Tyll who did most of their database of measurements for HeadRoom; when he left to do InnerFidelity, he does them now on a contract basis...
  13. mikeaj

    How Digital Audio works

      It's still coming from the real world and is continuous (not a true discontinuity), just sometimes with some ultrasonic content maybe.   If that doesn't fit into Nyquist frequency, it gets aliased down or filtered out somewhere in the A/D chain, in various parts (maybe both to some degree)...
  14. mikeaj

    Is It Really Worth 'Upgrading' Sennheiser HD 580/600/650 Cables?

    For what it's worth, I've tried all kinds of cable extensions and adapters and did a partial recable of a headphone that was breaking down. Usually it's the low-end where there's more room for things to be bad, right? Or do people say it really requires silver, cryotreating, or whatever else?
  15. mikeaj

    O2 AMP + ODAC

      No, that's not how it works. Just check the circuit diagram. The AC goes into half-bridge rectifiers into filters and 7812 / 7912 linear regulators to generate +12 V / -12 V rails. It's those +12 V and -12 V rails that charge the batteries and also power the electronics (the three op amps)...
  16. mikeaj

    What is an Audiophile, and what make headphones great?

    One thing to keep in mind about those audio recordings is that they're via a dummy head / simulator / mic / etc. That's the best way to do it, but gear aside, there are some limitations. Same caveats apply as to a headphone measurement site's data, like InnerFidelity's. The sound the mics pick...
  17. mikeaj

    Line level standard

    Redbook is 2V and a decent amount of home audio stuff is at 2V, but there are many, many exceptions. A large number of audiophile-targeted DACs go above 2V, some without any volume control. It's perhaps some part of a loudness arms race: louder usually sounds better when doing A/B comparisons...
  18. mikeaj


      Sure, 20 times more power than 0.05 mW is 1 mW. 20 times the value is 10*log10(20) = 13 dB more. So that's 90 + 13 = 103 dB SPL for 1 mW.
  19. mikeaj

    Do hard drives sound different?

    Yes, hard drives sound different. Listen for yourself.   As in, the drives themselves: the character and loudness of seek noise, vibrations, air whooshing.
  20. mikeaj

    How is DAC's resolving capability Measured?

    Output level (volume). Slight changes in volume impact how anybody hears details, balance of different things, and so on.   Or at least, that's the realistic, relevant, but maybe not that interesting response.   As for the usual measurables, it could be a number of things and a combination...
  21. mikeaj

    Headphone Ohms, whole headphone or just parts?

      The placement of the resistor wouldn't much matter so long as it's in series. Effect would be virtually the same.   The effect would not at all be like having headphones with the greater impedance. It would be more akin to increasing the amp's output impedance (reducing the damping factor...
  22. mikeaj

    (Efficiency or Sensitivity) Which is more demanding on amp's capability?

      The figure in dB/V is larger than the figure in dB/mW for pretty much all headphones, if that's what you're asking.   If you have 1 V input, if the load is 1000 ohms, then the power input will be 1 mW. If the load is less than 1000 ohms, like practically all headphones, the power will be...
  23. mikeaj

    (Efficiency or Sensitivity) Which is more demanding on amp's capability?

      What does that have to do with efficiency and sensitivity?     Or wait, are you just asking for a conversion between units for Sennheisers (which?) and the HiFiMAN HE-6? e.g. HD 800 @ 600 ohms, 102 dB SPL / 1 V -> 99.8 dB SPL / 1 mW? It's higher impedance and more sensitive so generally...
  24. mikeaj

    How does EQ exactly work?

    It's kind of difficult to go line-by-line understanding the first post because a couple key assumptions need to be addressed, so let's just go with some basics:   A decibel is a logarithmic unit to express a ratio. 3 dB is twice as much, whether it's the difference between 20 and 23 dB or...
  25. mikeaj

    What causes sound to be more puncy from the amp when you turn up the gain?

    Some people have made arguments in this case and others (without evidence, real justification that is pertinent) that the larger gain means a little less negative feedback (this part is true) and thus doesn't sound as ___________. Fill in the blank with some kind of certain quality.  ...