Why do most software audio volume controls have linear tapers? I would have guesses that simulated log-taper controls would be standard. Jerry -- Engineering is the art of making what you want from things you can get.
Audio volume controls
Started by ●May 1, 2011
Reply by ●May 1, 20112011-05-01
Jerry Avins wrote:> Why do most software audio volume controls have linear tapers? I would > have guesses that simulated log-taper controls would be standard.Mixer controls are linear, volume controls are logarithmic. VLV
Reply by ●May 1, 20112011-05-01
On May 1, 3:56�pm, Vladimir Vassilevsky <nos...@nowhere.com> wrote:> Jerry Avins wrote: > > Why do most software audio volume controls have linear tapers? I would > > have guesses that simulated log-taper controls would be standard. > > Mixer controls are linear, volume controls are logarithmic. > > VLVSo do charging leds on a mobile. Hardy
Reply by ●May 1, 20112011-05-01
Jerry Avins <jya@ieee.org> wrote:> Why do most software audio volume controls have linear tapers? I would > have guesses that simulated log-taper controls would be standard.I remember learning about this a looong time ago, including the letter to identify them, though now I forget the letter. It might be a forgotten art by now. -- glen
Reply by ●May 1, 20112011-05-01
I noticed that when the first digitally controlled attenuator chips came out they had linear steps. I assumed at the time that it was simpler to lay out the chip that way. Another mystery (to me) is why radio manufacturers stopped using square-law tuning capacitors on AM radios. This happened around the time that transistor radios came on the scene. The old valve AM radios had nice, linear frequency calibrations whereas the consumer transistor AM radios around now have nasty little tuning capacitors with semi-circular vanes, causing the stations to be squeezed up at the high-frequency end of the dial on the AM band and spread out along the low-frequency end. Regards, John On 1/05/2011 1:36 PM, Jerry Avins wrote:> Why do most software audio volume controls have linear tapers? I would > have guesses that simulated log-taper controls would be standard. > > Jerry > -- > Engineering is the art of making what you want from things you can get.
Reply by ●May 1, 20112011-05-01
On 1.5.11 11:39 , John Monro wrote:> I noticed that when the first digitally controlled attenuator chips came > out they had linear steps. I assumed at the time that it was simpler to > lay out the chip that way.The first Japanese transistor sets had quasi-log audio potentiometers: there was two linear sections with an annoying knee joining them.> Another mystery (to me) is why radio manufacturers stopped using > square-law tuning capacitors on AM radios. This happened around the time > that transistor radios came on the scene.My guess is that the question is about space inside the box. The square-law capacitors need much more free space around the open capacitor than a cap with semi-circular rotor.> The old valve AM radios had nice, linear frequency calibrations whereas > the consumer transistor AM radios around now have nasty little tuning > capacitors with semi-circular vanes, causing the stations to be squeezed > up at the high-frequency end of the dial on the AM band and spread out > along the low-frequency end.An old venerable tube AM set was a PITA to linearize by twisting the outer vanes to make the stations sit correctly on the scale. If the scale is squeezed there is no reason to do the time-consuming linearity tuning of the oscillator section. -- Tauno Voipio, OH2UG (since 50 years)
Reply by ●May 1, 20112011-05-01
On May 1, 4:56�am, Tauno Voipio <tauno.voi...@notused.fi.invalid> wrote:> On 1.5.11 11:39 , John Monro wrote: > > > I noticed that when the first digitally controlled attenuator chips came > > out they had linear steps. I assumed at the time that it was simpler to > > lay out the chip that way. > > The first Japanese transistor sets had quasi-log audio potentiometers: > there was two linear sections with an annoying knee joining them. > > > Another mystery (to me) is why radio manufacturers stopped using > > square-law tuning capacitors on AM radios. This happened around the time > > that transistor radios came on the scene. > > My guess is that the question is about space inside the box. > The square-law capacitors need much more free space around > the open capacitor than a cap with semi-circular rotor.Yes.> > The old valve AM radios had nice, linear frequency calibrations whereas > > the consumer transistor AM radios around now have nasty little tuning > > capacitors with semi-circular vanes, causing the stations to be squeezed > > up at the high-frequency end of the dial on the AM band and spread out > > along the low-frequency end. > > An old venerable tube AM set was a PITA to linearize by twisting > the outer vanes to make the stations sit correctly on the scale. > If the scale is squeezed there is no reason to do the time-consuming > linearity tuning of the oscillator section.No. The outer vanes were adjusted to track the tuning of the RF amplifier and the LO. This was cheaper and more exact than the padder- cum-trimmer approach and not much more difficult to trim. Jerry -- Engineering is the art of making what you want from things you can get.
Reply by ●May 1, 20112011-05-01
Jerry Avins wrote:> On May 1, 4:56 am, Tauno Voipio<tauno.voi...@notused.fi.invalid> > wrote: >> On 1.5.11 11:39 , John Monro wrote: >> >>> I noticed that when the first digitally controlled attenuator chips came >>> out they had linear steps. I assumed at the time that it was simpler to >>> lay out the chip that way. >> >> The first Japanese transistor sets had quasi-log audio potentiometers: >> there was two linear sections with an annoying knee joining them. >> >>> Another mystery (to me) is why radio manufacturers stopped using >>> square-law tuning capacitors on AM radios. This happened around the time >>> that transistor radios came on the scene. >> >> My guess is that the question is about space inside the box. >> The square-law capacitors need much more free space around >> the open capacitor than a cap with semi-circular rotor. > > Yes. > >>> The old valve AM radios had nice, linear frequency calibrations whereas >>> the consumer transistor AM radios around now have nasty little tuning >>> capacitors with semi-circular vanes, causing the stations to be squeezed >>> up at the high-frequency end of the dial on the AM band and spread out >>> along the low-frequency end. >> >> An old venerable tube AM set was a PITA to linearize by twisting >> the outer vanes to make the stations sit correctly on the scale. >> If the scale is squeezed there is no reason to do the time-consuming >> linearity tuning of the oscillator section. > > No. The outer vanes were adjusted to track the tuning of the RF > amplifier and the LO. This was cheaper and more exact than the padder- > cum-trimmer approach and not much more difficult to trim. > > Jerry >Elderly "sanity check". IIRC :) Did not mechanical multi blade capacitors have 'notches' in some blades? A half-century ago, I wasn't interested in any linearity between "dial markings" and "dial rotation".
Reply by ●May 1, 20112011-05-01
On 1.5.11 6:29 , Jerry Avins wrote:> On May 1, 4:56 am, Tauno Voipio<tauno.voi...@notused.fi.invalid> > wrote: >> On 1.5.11 11:39 , John Monro wrote: >> >>> I noticed that when the first digitally controlled attenuator chips came >>> out they had linear steps. I assumed at the time that it was simpler to >>> lay out the chip that way. >> >> The first Japanese transistor sets had quasi-log audio potentiometers: >> there was two linear sections with an annoying knee joining them. >> >>> Another mystery (to me) is why radio manufacturers stopped using >>> square-law tuning capacitors on AM radios. This happened around the time >>> that transistor radios came on the scene. >> >> My guess is that the question is about space inside the box. >> The square-law capacitors need much more free space around >> the open capacitor than a cap with semi-circular rotor. > > Yes. > >>> The old valve AM radios had nice, linear frequency calibrations whereas >>> the consumer transistor AM radios around now have nasty little tuning >>> capacitors with semi-circular vanes, causing the stations to be squeezed >>> up at the high-frequency end of the dial on the AM band and spread out >>> along the low-frequency end. >> >> An old venerable tube AM set was a PITA to linearize by twisting >> the outer vanes to make the stations sit correctly on the scale. >> If the scale is squeezed there is no reason to do the time-consuming >> linearity tuning of the oscillator section. > > No. The outer vanes were adjusted to track the tuning of the RF > amplifier and the LO. This was cheaper and more exact than the padder- > cum-trimmer approach and not much more difficult to trim. > > Jerry > -- > Engineering is the art of making what you want from things you can > get.It was for both. The oscillator side outer vanes were twisted to set the linearity, and the antenna section vanes (and maybe RF amplifier section) vanes were twisted to make the tracking. The fromt end tuning was quite broad in parctice, so the linearization was more important. It was still usual to have some of the padding capacitor in series with the oscillator section. -- Been there, done that Tauno Voipio
Reply by ●May 1, 20112011-05-01
On May 1, 3:48�pm, Richard Owlett <rowl...@pcnetinc.com> wrote:> Jerry Avins wrote: > > On May 1, 4:56 am, Tauno Voipio<tauno.voi...@notused.fi.invalid> > > wrote: > >> On 1.5.11 11:39 , John Monro wrote: > > >>> I noticed that when the first digitally controlled attenuator chips came > >>> out they had linear steps. I assumed at the time that it was simpler to > >>> lay out the chip that way. > > >> The first Japanese transistor sets had quasi-log audio potentiometers: > >> there was two linear sections with an annoying knee joining them. > > >>> Another mystery (to me) is why radio manufacturers stopped using > >>> square-law tuning capacitors on AM radios. This happened around the time > >>> that transistor radios came on the scene. > > >> My guess is that the question is about space inside the box. > >> The square-law capacitors need much more free space around > >> the open capacitor than a cap with semi-circular rotor. > > > Yes. > > >>> The old valve AM radios had nice, linear frequency calibrations whereas > >>> the consumer transistor AM radios around now have nasty little tuning > >>> capacitors with semi-circular vanes, causing the stations to be squeezed > >>> up at the high-frequency end of the dial on the AM band and spread out > >>> along the low-frequency end. > > >> An old venerable tube AM set was a PITA to linearize by twisting > >> the outer vanes to make the stations sit correctly on the scale. > >> If the scale is squeezed there is no reason to do the time-consuming > >> linearity tuning of the oscillator section. > > > No. The outer vanes were adjusted to track the tuning of the RF > > amplifier and the LO. This was cheaper and more exact than the padder- > > cum-trimmer approach and not much more difficult to trim. > > > Jerry > > Elderly "sanity check". IIRC :) > � �Did not mechanical multi blade capacitors have 'notches' in > � �some blades?Yes. Bending the individual pieces was how the capacitance was varied from the production standard.> A half-century ago, I wasn't interested in any linearity between > "dial markings" and "dial rotation".Except for communications receivers, approximate linearity was all anyone asked for. Jerry
