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WTB: VU Meters
On Thu, 7 Feb 2008 09:19:52 -0000, "David Looser"
wrote: "Eeyore" wrote in message ... "Dave Plowman (News)" wrote: Don Pearce wrote: Don't forget 1 - 2 - 3 - TEST - 5 - 6 - 7 where TEST would correspond to 0VU on a VU meter. [Sharp intake of breath] What a VU should read at 'zero level' is the source of many a debate. ;-) Is it ? It reads '0' with a 1.228 V input and loads the circuit with 7.5 kohms. A 1.228V rms sinewave to be precise. What voltage of a non-sinewave signal corresponds to 0VU is another thing entirely. All that matters is that all true VU meters read the same. David. Oops, when I said 0VU, what I meant was 0dBu. 0VU is +4dBu. So a sine wave that shows 0 on a VU meter will read 4dB above the TEST level on a PPM. So a 0VU sine wave will read Almost + 6 on a Nordic PPM (IEC 60268-10/1) 5 on a BBC PPM (IEC 60268-10/11a) +4 on an EBU PPM (IEC 60268-10/11b) d -- Pearce Consulting http://www.pearce.uk.com That 7.5kOhms shunted across an audio circuit whose Zs is below 600 Ohms ... is that a pure DC load or Impedance? Surely there is the germanium bridge's effect which corrupts audio awfully. So a unity-gain AF buffer has to be used to drive the VU package. Regarding the examples given above, on steady-state signals, why are Nordic PPMs nearly 2dB more sensitive, ie, reading 2dBs higher, than needles in BBC or DIN/EBU counterparts? I wonder what is their max allowed peak level? Is it 7 perhaps? Does their driver 'law' expand meter levels above peak 4 (0dBu) or is Nordic line-up level lower? Jim |
WTB: VU Meters
On Fri, 08 Feb 2008 18:04:50 GMT, "jim Gregory"
wrote: On Thu, 7 Feb 2008 09:19:52 -0000, "David Looser" wrote: "Eeyore" wrote in message ... "Dave Plowman (News)" wrote: Don Pearce wrote: Don't forget 1 - 2 - 3 - TEST - 5 - 6 - 7 where TEST would correspond to 0VU on a VU meter. [Sharp intake of breath] What a VU should read at 'zero level' is the source of many a debate. ;-) Is it ? It reads '0' with a 1.228 V input and loads the circuit with 7.5 kohms. A 1.228V rms sinewave to be precise. What voltage of a non-sinewave signal corresponds to 0VU is another thing entirely. All that matters is that all true VU meters read the same. David. Oops, when I said 0VU, what I meant was 0dBu. 0VU is +4dBu. So a sine wave that shows 0 on a VU meter will read 4dB above the TEST level on a PPM. So a 0VU sine wave will read Almost + 6 on a Nordic PPM (IEC 60268-10/1) 5 on a BBC PPM (IEC 60268-10/11a) +4 on an EBU PPM (IEC 60268-10/11b) d -- Pearce Consulting http://www.pearce.uk.com That 7.5kOhms shunted across an audio circuit whose Zs is below 600 Ohms ... is that a pure DC load or Impedance? Surely there is the germanium bridge's effect which corrupts audio awfully. So a unity-gain AF buffer has to be used to drive the VU package. Regarding the examples given above, on steady-state signals, why are Nordic PPMs nearly 2dB more sensitive, ie, reading 2dBs higher, than needles in BBC or DIN/EBU counterparts? I wonder what is their max allowed peak level? Is it 7 perhaps? Does their driver 'law' expand meter levels above peak 4 (0dBu) or is Nordic line-up level lower? Jim When I said that a Nordic reads almost +6, I mean the needle is at 4, but there isn't a mark there, so what you see is the needle a bit below the 6 mark. The actual calibration marks a Nordic: -36 -30 -24 -18 -12 -6 TEST +6 +9 BBC: 1 2 3 4 5 6 7 EBU -12 -8 -4 TEST +4 +8 +12 So the Nordic PPM has a far wider range than the BBC or EBU. Goodness only knows why they do that, I can't imagine any kind of reason why I might want to know that a signal is peaking at -36. The Nordic PPM also has a much faster dynamic response than the BBC and EBU, which are specified identically. d -- Pearce Consulting http://www.pearce.uk.com |
WTB: VU Meters
"Don Pearce" wrote in message ... On Fri, 08 Feb 2008 18:04:50 GMT, "jim Gregory" wrote: On Thu, 7 Feb 2008 09:19:52 -0000, "David Looser" wrote: "Eeyore" wrote in message ... "Dave Plowman (News)" wrote: Don Pearce wrote: Don't forget 1 - 2 - 3 - TEST - 5 - 6 - 7 where TEST would correspond to 0VU on a VU meter. [Sharp intake of breath] What a VU should read at 'zero level' is the source of many a debate. ;-) Is it ? It reads '0' with a 1.228 V input and loads the circuit with 7.5 kohms. A 1.228V rms sinewave to be precise. What voltage of a non-sinewave signal corresponds to 0VU is another thing entirely. All that matters is that all true VU meters read the same. David. Oops, when I said 0VU, what I meant was 0dBu. 0VU is +4dBu. So a sine wave that shows 0 on a VU meter will read 4dB above the TEST level on a PPM. So a 0VU sine wave will read Almost + 6 on a Nordic PPM (IEC 60268-10/1) 5 on a BBC PPM (IEC 60268-10/11a) +4 on an EBU PPM (IEC 60268-10/11b) d -- Pearce Consulting http://www.pearce.uk.com That 7.5kOhms shunted across an audio circuit whose Zs is below 600 Ohms ... is that a pure DC load or Impedance? Surely there is the germanium bridge's effect which corrupts audio awfully. So a unity-gain AF buffer has to be used to drive the VU package. Regarding the examples given above, on steady-state signals, why are Nordic PPMs nearly 2dB more sensitive, ie, reading 2dBs higher, than needles in BBC or DIN/EBU counterparts? I wonder what is their max allowed peak level? Is it 7 perhaps? Does their driver 'law' expand meter levels above peak 4 (0dBu) or is Nordic line-up level lower? Jim When I said that a Nordic reads almost +6, I mean the needle is at 4, but there isn't a mark there, so what you see is the needle a bit below the 6 mark. The actual calibration marks a Nordic: -36 -30 -24 -18 -12 -6 TEST +6 +9 BBC: 1 2 3 4 5 6 7 EBU -12 -8 -4 TEST +4 +8 +12 So the Nordic PPM has a far wider range than the BBC or EBU. Goodness only knows why they do that, I can't imagine any kind of reason why I might want to know that a signal is peaking at -36. The Nordic PPM also has a much faster dynamic response than the BBC and EBU, which are specified identically. d -- Pearce Consulting http://www.pearce.uk.com So, what we deduce from that is, in the case of a Nordic PPM, its TEST mark lies between -6 and +6 marks and is therefore 0dBu. What's so new? Assuming curve law in driver amp is correctly set up, who needs to know what source or passage is regularly achieving only about -33dB below line-up? Do you have a pic of that maverick scale? Jim |
WTB: VU Meters
-- Iain Aural perception is a skill that requires study and careful development over along period of time. Few have it as a natural gift. "jim Gregory" wrote in message ... "Don Pearce" wrote in message ... On Fri, 08 Feb 2008 18:04:50 GMT, "jim Gregory" wrote: On Thu, 7 Feb 2008 09:19:52 -0000, "David Looser" wrote: "Eeyore" wrote in message ... "Dave Plowman (News)" wrote: Don Pearce wrote: Don't forget 1 - 2 - 3 - TEST - 5 - 6 - 7 where TEST would correspond to 0VU on a VU meter. [Sharp intake of breath] What a VU should read at 'zero level' is the source of many a debate. ;-) Is it ? It reads '0' with a 1.228 V input and loads the circuit with 7.5 kohms. A 1.228V rms sinewave to be precise. What voltage of a non-sinewave signal corresponds to 0VU is another thing entirely. All that matters is that all true VU meters read the same. David. Oops, when I said 0VU, what I meant was 0dBu. 0VU is +4dBu. So a sine wave that shows 0 on a VU meter will read 4dB above the TEST level on a PPM. So a 0VU sine wave will read Almost + 6 on a Nordic PPM (IEC 60268-10/1) 5 on a BBC PPM (IEC 60268-10/11a) +4 on an EBU PPM (IEC 60268-10/11b) d -- Pearce Consulting http://www.pearce.uk.com That 7.5kOhms shunted across an audio circuit whose Zs is below 600 Ohms ... is that a pure DC load or Impedance? Surely there is the germanium bridge's effect which corrupts audio awfully. So a unity-gain AF buffer has to be used to drive the VU package. Regarding the examples given above, on steady-state signals, why are Nordic PPMs nearly 2dB more sensitive, ie, reading 2dBs higher, than needles in BBC or DIN/EBU counterparts? I wonder what is their max allowed peak level? Is it 7 perhaps? Does their driver 'law' expand meter levels above peak 4 (0dBu) or is Nordic line-up level lower? Jim When I said that a Nordic reads almost +6, I mean the needle is at 4, but there isn't a mark there, so what you see is the needle a bit below the 6 mark. The actual calibration marks a Nordic: -36 -30 -24 -18 -12 -6 TEST +6 +9 BBC: 1 2 3 4 5 6 7 EBU -12 -8 -4 TEST +4 +8 +12 So the Nordic PPM has a far wider range than the BBC or EBU. Goodness only knows why they do that, I can't imagine any kind of reason why I might want to know that a signal is peaking at -36. The Nordic PPM also has a much faster dynamic response than the BBC and EBU, which are specified identically. d -- Pearce Consulting http://www.pearce.uk.com So, what we deduce from that is, in the case of a Nordic PPM, its TEST mark lies between -6 and +6 marks and is therefore 0dBu. What's so new? Assuming curve law in driver amp is correctly set up, who needs to know what source or passage is regularly achieving only about -33dB below line-up? Do you have a pic of that maverick scale? Jim Hello Jim, You can see a comparison of the scales on a page taken from the Tonmeister study material, at: http://www.tonmeister.ca/main/textbook/node757.html Iain |
WTB: VU Meters
On Sun, 10 Feb 2008 20:07:12 +0200, "Iain Churches"
wrote: So, what we deduce from that is, in the case of a Nordic PPM, its TEST mark lies between -6 and +6 marks and is therefore 0dBu. What's so new? Assuming curve law in driver amp is correctly set up, who needs to know what source or passage is regularly achieving only about -33dB below line-up? Do you have a pic of that maverick scale? Jim Hello Jim, You can see a comparison of the scales on a page taken from the Tonmeister study material, at: http://www.tonmeister.ca/main/textbook/node757.html Iain That appears to have yet another (minor) variant of the Nordic scale. There are just too many. d -- Pearce Consulting http://www.pearce.uk.com |
WTB: VU Meters
"Don Pearce" wrote in message ... On Sun, 10 Feb 2008 20:07:12 +0200, "Iain Churches" wrote: So, what we deduce from that is, in the case of a Nordic PPM, its TEST mark lies between -6 and +6 marks and is therefore 0dBu. What's so new? Assuming curve law in driver amp is correctly set up, who needs to know what source or passage is regularly achieving only about -33dB below line-up? Do you have a pic of that maverick scale? Jim Hello Jim, You can see a comparison of the scales on a page taken from the Tonmeister study material, at: http://www.tonmeister.ca/main/textbook/node757.html Iain That appears to have yet another (minor) variant of the Nordic scale. There are just too many. d -- Pearce Consulting http://www.pearce.uk.com I see in Nordic PPMs [categorised in the tabulated columns of fig.10.18 in the PDF Iain linked us to], there are... also finer, 3 dB incremental marks as well as the sequence of coarser, 6dB graduations. And they come in other designs? What a pallaver! Give me the BBC or EBU types anyday. Jim |
WTB: VU Meters
jim Gregory wrote: So, what we deduce from that is, in the case of a Nordic PPM, its TEST mark lies between -6 and +6 marks and is therefore 0dBu. What's so new? Assuming curve law in driver amp is correctly set up, who needs to know what source or passage is regularly achieving only about -33dB below line-up? Do you have a pic of that maverick scale? Here are some comparisons. http://www.tonmeister.ca/main/textbook/node757.html Graham |
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