> > I think you want a delay independent of frequency. Not so easy with R-C. >R-C and R-L circuitry ofcourse. Shall I draw a circuit for you? One that works perfectly well for 100Hz - 22kHz ?> > What is "deviation factor"? Deviation from what? >I meant cheap components, the ones that say they are 2kOhm but in fact they are 1,7kOhm. This is the deviation I meant. Perhaps I shoud have used another word.
Stereo expansion algorithm
Started by ●July 6, 2004
Reply by ●July 7, 20042004-07-07
Reply by ●July 7, 20042004-07-07
Rob Vermeulen wrote:>>I think you want a delay independent of frequency. Not so easy with R-C. >> > > R-C and R-L circuitry ofcourse. Shall I draw a circuit for you? One that > works perfectly well for 100Hz - 22kHz ?The canonical pure delay is an L-C approximation to a transmission line. I know how to build one. Even though perfection is relative, your R-C/L-C version with a bandwidth of nearly eight octaves sounds interesting. Please show me the circuit.>>What is "deviation factor"? Deviation from what? >> > > > I meant cheap components, the ones that say they are 2kOhm but in fact they > are 1,7kOhm. This is the deviation I meant. > Perhaps I shoud have used another word.I think the word you want is "tolerance". Sometimes I call it "slop". Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●July 7, 20042004-07-07
"Rob Vermeulen" <rvermeulen@arbor-audio-antispam-.com> wrote in message news:10enq0ugf2k6pb4@corp.supernews.com...> > > > > I think you want a delay independent of frequency. Not so easy with R-C. > > > R-C and R-L circuitry ofcourse. Shall I draw a circuit for you? One that > works perfectly well for 100Hz - 22kHz ?I'd like to see a practical analog circuit that could delay a signal by say 20ms independent of frequency over the audio range (or at least 100Hz-22kHz).
Reply by ●July 7, 20042004-07-07
My TV has a stereo expansion mode. After listening to it a bit, I'm fairly sure it uses the algorithm Stephan describes. I'm remember one time I was listening to a musical performance and found the mix to be very bad--I could barely hear the lead vocal and the background vocals and accompaniment music were way too loud. When I turned off the "wide" mode, it sounded much better balanced. Reduction in volume of center-panned lead vocals would be a natural consequence of this algorithm. "Stephan M. Bernsee" <spam@dspdimension.com> wrote in message news:42c34ef.0407062041.46392b4a@posting.google.com...> No typo. You subtract the center part of the stereo image from both > the left and right channels. This will emphasize anything that is not > present in both channels, therefore making the stereo image appear > "wider". It is true that the overall signal level drops if you have a > mono signal, but I guess you could just switch the algorithm off in > that case. Checking for mono is fairly easy, for example by making > sure fabs(left-right) is always below a certain threshold. > > --smb > > Jerry Avins <jya@ieee.org> wrote in messagenews:<40eb15e6$0$3088$61fed72c@news.rcn.com>...> > Stephan M. Bernsee wrote: > > > float mono = (left+right)*.5; > > > left -= amount * mono; > > > right -= amount * mono; > > > > > > For 0. < amount <= 1. > > > > > > That's basically all there is to it. > > > > Typo? right += amount * mono; ? > > > > > > --smb > > > > > > > > > jbek@altavista.net (Jesper B. Kristensen) wrote in messagenews:<71e1e102.0407060151.1dc86912@posting.google.com>...> > > > > >>Hi, > > >> > > >>Can anybody point me in the direction of a decent 'stereo expansion' > > >>algorithm (by this I mean the sort of thing commonly found in e.g. > > >>TVs, that makes a normal stereo image sound wider than it actually > > >>is)? > > >> > > >>Thanks, > > >>Jesper > > > > Jerry
Reply by ●July 7, 20042004-07-07
Jon Harris wrote:> "Rob Vermeulen" <rvermeulen@arbor-audio-antispam-.com> wrote in message > news:10enq0ugf2k6pb4@corp.supernews.com... > >>>I think you want a delay independent of frequency. Not so easy with R-C. >>> >> >>R-C and R-L circuitry ofcourse. Shall I draw a circuit for you? One that >>works perfectly well for 100Hz - 22kHz ? > > > I'd like to see a practical analog circuit that could delay a signal by say 20ms > independent of frequency over the audio range (or at least 100Hz-22kHz).Western Electric had one on display at the 1939 Worlds Fair with about a 10 ms delay. They were standard (but expensive) simulated long lines used to test and exercise equipment to be used in the field. (Remember that the long-distance record, established years before, was New York to Denver without repeaters. Thorough understanding and adjustment of line parameters were needed for that.) At the fair, it was connected to a headset at one end and a microphone at the other. The visitor's challenge was to speak coherently into the microphone while wearing the headset. Few could manage it. The demonstrator told me that it consisted of cascaded pi sections with m-derived end sections. It made no sense to me at the time, but I remembered the words. "Now I are one." Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
