Cd frequency responce ?

[woody]

I know that some clasical music records have a lot of content
below 20hz. When cd's are produced are these subsonics also
included?

[Hi-Q]

I would be interested to know what orchestral instrument produces a fundamental tone lower than 20 Hz

[kevinkr]

Beyond the obvious large pipe organ (16Hz) here is a list - I will admit I was somewhat surprised. More instruments on this list than I would have ever expected.. (Ignoring the midi stuff.)

http://www.contrabass.com/pages/frequency.html

There is no inherent lower limit on the LF response of a cd, but practically speaking most players don't go too much below 10 - 20Hz, and the rest depends heavily on microphones and studio hardware. Usable 16Hz shouldn't be a problem with most players, but speakers that can reproduce those frequencies cleanly are relatively large and expensive. IMO most LFE HT subwoofers generate multiple harmonics of the fundamental which probably isn't a good thing. In the case of a 16Hz organ note I think you are hearing the 2nd harmonic, but you can feel the fundamental if present.

[AndrewT]

I seem to recall that the low frequency limit for CD is an octave or more above the DVD standard.

Can anyone refer us to the Philips' CD standard?

[Hi-Q]

http://en.wikipedia.org/wiki/Red_Book_(audio_CD_standard)

Red Book is the official CD specification as listed above.
Les

[AndrewT]

http://en.wikipedia.org/wiki/Red_Boo...CD_standard%29
says 20Hz lower limit, but can Wikipedia be relied on?

[Hi-Q]

In theory I suppose you can take a CD down to 0Hz, the sampling rate limits the top end to around 22kHz. I did find the following whilst surfing on sonicflare.com

"The CDs themselves are normally cut at 10Hz unless you master them not to. Though , I have never seen any mastering software that allows audio below this either, not that I have looked a lot be be honest. However, most pre-amps and other audio gear also cut at approx 10 Hz either due to that they are designed to do this to prevent damage to loudspeakers (DC kill speakers) or that they contain caps in the audio path that makes it impossible for frequencies below 4Hz to pass.
So, in essence, specially mastered CDs,CD players and amps are needed to feed this bass beast."

Other sites visited all give the response 20Hz - 20kHz.
The opening thread referred to classical records, I assume Vinyl medium, these are usually rolled off much sooner due to reproduction constraints, for example turntable rumble.

[kevinkr]

I missed the reference to LPs, but due to arm/cartridge resonances and tracking issues with large groove modulations I would doubt any LP is cut with significant signal content below 20Hz.

[Hi-Q]

Yep, those were the words I was looking for

[Speedskater]

The upper frequency is a limit because the Nyquist police won't let us go any higher. I think that the 20 Hz low frequency is a specification not a limit. We could put a sub 1 Hz signal (maybe an almost DC signal) on a CD or a WAV file. But then, what do we do with it?