Blog entry

The HD580 Response

Posted by admin on October 11, 2007

Here is a log-log plot of the Sennheiser HD580 response at the eardrum reference point, measured by Brian Moore on the Kemar dummy head, average of large and small ears. The HD580 has a nominal response of 104 dB SPL at eardrum given a 1 volt RMS sinusoidal input at 1khz. Some audiometric setups drive the HD580 in series with a 300 ohm resistor for a total load of 600 ohms, although its not clear to me that doing this is necessary.

[inline-center:2=HD580 Response]

Blog entry

Representation of a compressor's transfer function

Posted by admin on October 11, 2007

A simple definition of a compressors input/output function is a piecewise linear function with a knee-point or compression threshold, below which gain is constant, a compressed section with slope = 1/ratio, and a linear section (0 db gain) at high levels:

[inline-center:compmodel1.png=Compression Function (blue) and Linear Reference (purple)]

Blog entry

Collected Thoughts on the uOSC / PIC USB Firmware

Posted by admin on October 10, 2007

- I recommend we go to a "compact" OSC format where we use a blob to encode a section of binary data corresponding to the dio and adc registers, instead of separate register names and floating point values. This would free up at least 4kb for the float-table, and support 12-bit and bigger dense vectors, etc.

Blog entry

One Month in Paris

Posted by Aaron Einbond on October 2, 2007

Most people think what could I do, I think what shouldn't I do. What I should do perhaps is involved with the fact that I'm Jewish and what is known as Jewish paranoia. I don't feel comfortable enough to feel that everything is on my side and that it's going to work just the way I want it. --Morton Feldman

Blog entry

Cochlear Modeling Retrospective / Richard Lyon, EarClub

Posted by admin on October 1, 2007

This talk is primarily an overview of the history of Cochlear modeling. As such it progresses through a series of models from crude to refined; at the conclusion Lyon basically states that the model problem is "solved" (thus qualifying the "retrospective").

- Pitch is a primary cue for sound separation (ref 1912)
- Thomas Young (1800) "pitch is the period of recurrence of a sound"

Blog entry

SHRC Meeting 10/1/2007

Posted by admin on October 1, 2007

**Order of operations**

- Compressor -> Hearing Loss Simulator -> Listener

**HL Simulator**

- Frequency smearing effect is not included
- Hilbert approach needs long delay
- Transform; ear reference point to cochlea (ITU P.58 Telephone)
- Relevant publication:

Pages