Recent content by charleski

  1. charleski

    Ultimate closed back (portable-ish) when using eq

    The only area you'll really run into problems is with pipe resonances, which will generally produce a narrow major error (either peak or dip) in the 5-10kHz region. You shouldn't be attempting to EQ these anyway, as they're non-minimum-phase and you need to learn to identify them. If your...
  2. charleski

    Ultimate closed back (portable-ish) when using eq

    No. This is why it’s essential to measure with the EQ applied and adjust the EQ so that the difference between measurements is very small. The differences in acoustic impedance (of both headphone and fixture) make it hard to develop a transfer function that can translate across variations in...
  3. charleski

    Lawton Chambers for TH610!

    You're just needlessly introducing confounding factors. Take one pair of headphones and test them with the stock cups, then switch to one of the Lawtons and retest the same pair. If you're having problems with 'weird EARS resonances' from 3kHz up then plot multiple sweeps with independent...
  4. charleski

    Lawton Chambers for TH610!

    It looks like there's quite a lot of inter-unit variation. Maybe it would be more instructive to test the same pair with stock and custom enclosures (it might be an idea to do multiple measurements, reseating inbetween, to check the precison of your setup).
  5. charleski

    Ultimate closed back (portable-ish) when using eq

    Unfortunately, if you are EQing based on measurements of other headphones, then you aren't really matching them to the target. Measurements from oratory, for instance, will get you reasonably close to the target, but there's sufficient variation between units, pads, fitting, etc that you're...
  6. charleski

    A testimonial about "EMI meters"

    I think the horrifyingly dangerous effects of EMI were covered quite comprehensively in Better Call Saul:
  7. charleski

    Review and Measurements of Schiit Yggdrasil V2 DAC

    Still a lot of modulation of the noise floor (over 5 times higher with 20kHz signal compared to 1kHz). Pity.
  8. charleski

    Do I need to clean my LP's?

    I had to laugh at the bit where he celebrates the amount of time this machine saves him. You probably already know the obvious snarky digital riposte, so I’ll resist making it. :) But it’s a bit disappointing that even a high-end washer like this still leaves clearly audible surface noise...
  9. charleski

    The ear can repair hair cells according to a new non-replicated study.

    It’s important to note that the authors here are describing a naturally-occurring repair process that is, presumably, already at work. There’s a wide gap between this and finding a therapy that will correct or even prevent noise-induced hearing damage. But it does suggest a possible pathway...
  10. charleski

    TANCHJIM Space Portable Headphone Adapter Review

    I recommend skipping the marketing fluff at the start and just looking at the data specs. Per Table 3-9 the fast roll-off filter on a 44.1kHz signal is down 0.01dB at 19.999kHz and -3dB at 21.256kHz, then -110dB at 24.123kHz. Not quite as good at the best offerings from ESS or AKM, but...
  11. charleski

    TANCHJIM Space Portable Headphone Adapter Review

    You can find plots for the filters provided in the datasheet: https://statics.cirrus.com/pubs/proDatasheet/CS43131_DS1155F2.pdf#page141 It’s basically linear or minimum phase and proper or poor attenuation.
  12. charleski

    Trying to understand DAC accuracy.

    I'd recommend chapter two of Ken Pohlman's book. For a large signal, the quantisation error becomes uniformly distributed and can be treated as noise. This leads to the 6.02n+1.76dB signal-to-error equation. But for small signals, the error becomes correlated with the signal and thus is better...
  13. charleski

    TANCHJIM Space Portable Headphone Adapter Review

    Is the USB receiver chip asynchronous or isochronous? This can be tested on a PC with the Thesycon dumper. The chief reason I went with the dongle I currently use (JCally AP90) is that it runs an asynchronous interface. The Tempotec Sonata I used previously is very good, but its isochronous...
  14. charleski

    RPI4 Streamer and Peachtree Pre DAC

    The big problem here is that it’s not showing up in lsusb. Step 1 would be to make sure the Peachtree is actually working properly. Does it work if you connect it via USB to a PC? Try using a different cable, or setting it to USB 1 mode.
  15. charleski

    Driving headphones

    One which is used in a lot of headphone amps is the TI 6120. https://www.ti.com/lit/gpn/tpa6120a2
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