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Posts by briskly

The decibel is defined by ratio of power. Double pressure or voltage represents 6 dB. 10 dB SPL roughly relates to a change of perceived loudness at 1 kHz by a factor of 2, but represents 10x power and ~3.16 the pressure.Units of dB SPL and dBV reference a ratio compared to a certain value, generally 20 micropascals and 1 Volt rms.   Reminiscent of JJ Johnston's old tube/transistor amp comparison. The story starts before 20 minutes in.  
I think the stated goal was for acoustic impedance matching and managing wave diffraction. I don't know the dimensions of the slits well enough to evaluate if any meaningful impedance difference is to be had from it. There was the disassembly of the LCD-3F a while back that makes it all a bit questionable whether Audeze can achieve their started goals.With the limited driver excursion and volume displacement through the wide slits that LCDs used in their stators, I find it...
These types of measurements include the frequency response of the ear canal and the diffraction of the outer ear. If you had noticed from my previous post, there was a measurement of a headphone's response from inside the headphone paired with the subjectively determined response of the same headphone.The sound input before entering the ear should still be flat.
Our goal in this case of equalizing by ear is get a response that seems flat. Diffuse field response is not intended, but that is the result these tend to follow.Loudness adjustments will be needed when done by ear, especially as dependent on level. The middle and inner ear have compression mechanisms that increase the input range of sound, and also affect the transfer response when active. This is the response of the loudspeaker in the listening room used in the Harman...
Neutral curve has a simple answer: headphone insertion gain matched to or approximately close to the subject's diffuse field transfer function. You would get that using reference noise and sweeps. The problem is that people tend not to like that, which is what inspires all this research. Harman takes the position that a downward sloping response, from room absorption and LF bumps, in speaker listening seem more natural to listeners, and thus should be reflected in headphones.
Some measurements here. Link.   Competent enough, besides the slightly too high output impedance for some crossover fitted IEMs, at 3 ohms. Measurements are pretty typical for the line.
I do not know of earphone studies in particular, but audible effects of phase and polarity are preferentially tested in anechoic chamber or with headphones. Not all instruments can be identified by polarity even over headphone, and typical recording techniques of multi-miking or anything more than a single instrument tend to make this more difficult to distinguish.
This was made from analysis of headphone measurement data from innerfidelity, and at the time there weren't many lower range Stax measured. You can always go over it yourself using the criterion established in the first post, and the Lambdas generally do well based on that, besides some minor quibble with the bass response.
Is there any particular reason to test a DAC using a 997 Hz sine instead of 1kHz? I figure that 48/96/192 kHz sampling rates are integer multiples of 1kHz, but what difference could we expect from that?
The reference plane in the human ear canal is defined as corresponding to the position in the canals where plugs would normally terminate in the ear. See here.This is around the second bend of the canals, where the cartilage makes way for the skull proper, as stated in the 711 simulation you linked. Hence the reference to the bony part of the ear canal. As to @speakerphone and distance to reference plane measurements, a snippet regarding insertion and reference plane...
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