Rerurn to Romy the Cat's Site


In the Forum: Didital Things
In the Thread: Revisiting DSP
Post Subject: It is NOT FM is Analog Signal Processing vs DSPPosted by Romy the Cat on: 5/19/2014
fiogf49gjkf0d
 steverino wrote:
FM is Analog Signal Processing vs DSP. The compression aspect is only really intrusive on orchestral works. Pop and jazz are already compressed and chamber music presents a more limited dynamic range if not limited contrast. But on the evidence most listeners have no problem with dynamic compression. To be fair, audio systems even with horns impose a noticeable lag on dynamic changes on top of those in the live performance where they are much smoother (and more differentiated by instrument) anyway

Well, first of all there is no such a thing as Analog Signal Processing in FM, there is no analog broadcasting anymore.  There is nothing wrong in DSP during FM and all stations nowadays send signal from studio to transmitter as digital stream. Again, there is nothing wrong with that. If a signal juts sliced by AD processor and then reconstructed on another side by DAC then it would be fine. The problem is that stations are trying to save money on bandwidth and digitally  compress own stream, that cause math more damage than extra 25 AD to DA straight conversions. There is many other things that they do that fuck up signal. For instance there are regulations that demands that HD Radio shall be synchronous with FM but they never are there are reasons for it). So, what the do is to select one steam and Master , another stream and Slave and they the yank the Slave steam arcos time domain each let say 1 second to assure that the signals are synchronous and if a person loses HDFM signal and his tuner automatically switches to FM then the user would not note it. Well, FM doe not loose signal in binary fashion, HD Radio does, so all station that broadcast in both HD Radio and FM do use HD Radio as master. So, any station that does dual broadcast has FM signal already compromised. I have written about it before. There are many other things but this is not FM thread.

I would like to note one more things. Compression is not inherent evil of FM, it is how digital limiters and compressor are used by station personal. Mostly they used very barbarically and this is the problem. I can only assure you that if we had playback music with dynamic range limited by FM dynamic range we would have much better music then what we have today. FM has 50dB dynamic range, not enough, right? Well, vinyl has 50-60dB and I did not hear people complaining too much about vinyl dynamic range. (Some special pressing vinyl might push 70dB however). The 16bit is 96dB capable but in reality it never goes over 60-65db. Mastering, the stupid one, kills everything. The High Resolution formats of cause are more  dymicly capable. The 24bit recording are effectively 144dB of dynamic range but there are no true 24bit possessors out there and practical range of microphone are 120dB, so the human ears. There are a LOT of compression if concert halls and  to get 80-90dB of dynamic range is practically impossible from the positions where the orchestral sections are properly mixed. So, generally the practical dynamic range would be 60-80dB. Trust me, if you hear live, unmixed, unlimited FM at 60dB it would be all that you need.

Rerurn to Romy the Cat's Site