Posted by Guest on 11/09/06 00:37

--
This post is Sponsored by: www.overheadsoft.com

http://www.linkreferral.com/cgi-bin/linkreferal/adwel.cgi?oldrefid=20013
"Randy Yates" <yates@ieee.org> wrote in message
news:m3mz71blqo.fsf@ieee.org...
> Jim Gilliland <usemylastname@cheerful.com> writes:
>
>> Guest wrote:
>>> Jim Gilliland wrote:
>>>> Guest wrote:
>>>>
>>>>> I have read over the last few years about HDMI/DVI cables being all
>>>>> the same regardless of build quality because "ones and zeros are
>>>>> ones and zeros. It either works or it does not." This type of
>>>>> reasoning makes sense on it's face, but then I recalled having a
>>>>> Monster Cable optical cable and then an Acoustic Research optical
>>>>> cable and I noticed a very big difference in sound quality. The AR
>>>>> outperformed the Monster to a very larger degree.
>>
>>>> Really? Can you describe the difference between the sound of the two
>>>> cables?
>>> Yes. The Monster sounded flat (some people may love that) and lower
>>> in volume. It lacked detail, kick and bass. The AR had kick,
>>> clarity, bass and it was louder. It gave the music and surround
>>> sound true impact.
>>
>> And to what do you attribute this difference in sound? How do you
>> suppose the cable altered the bit stream to cause the audible
>> difference that you believe you heard?
>>
>> I'm not sure how to interpret words like "kick" and "impact", but
>> words like "louder" and "bass" have a fairly specific meaning. In
>> order to impact the volume of a digital signal, some fairly simple
>> arithmetic needs to take place. In order to impact just the low
>> frequency portion of the signal, some rather more sophisticated
>> arithmetic must take place.
>>
>> Apparently, one (or perhaps both!) of your cables is able to do some
>> fairly sophisticated digital processing - changing the bitstream in
>> such a way that the values carried by each 16-bit word were modified
>> to create more or less bass.
>>
>> Changing the bass characteristics of the music would require that your
>> cable change each successive 16-bit word in exactly the right
>> direction (some values increased, some decreased, some left unchanged)
>> in exactly the right sequence over an extended period of time. And it
>> would have to do all that without losing any of the signal bits
>> (pre-emphasis and so on), nor mixing up any of the interleaved samples
>> for the right and left channels.
>
> Jim,
>
> You forgot to mention that this feat would also require scaling the
> convolution sum (from the bass FIR filter) appropriately with the
> right number of guard bits and the right requantization back to the
> native data path width, possibly utilizing psychoacoustic noise-shaping.
>
>> I think this is an amazing discovery! You shouldn't be telling us
>> about it here - you should be documenting your discovery and sending
>> it to the Patent Office! Imagine that a simple piece of fiber can do
>> processing that we thought required a sophisticated DSP integrated
>> circuit. What a wonderful world we live in!
>
> Indeed.

Make jokes or try it for yourselves.

[Back to original message]