I have to agree that liner taper on the Orion audio control isn't the right
approach. It's difficult to crank the volume down to a low level without
cutting it off completely, and takes too long to increase it. Audio taper
would be much better.
73, Dick WC1M
> -----Original Message-----
> From: James C. Garland [mailto:4cx250b@muohio.edu]
> Sent: Tuesday, January 20, 2004 7:43 AM
> To: orion@contesting.com; tentec@contesting.com
> Subject: [TenTec] Orion audio gain controls
>
>
> Hi Gang,
> I notice that the Orion uses a linear taper on its volume encoders,
> rather than an audio taper, which is the convention used in
> virtually all
> other radios, audio systems, TVs, etc. As a reminder, an audio taper
> compensates for the logarithmic response of the human ear.
> It gives an
> extra boost to the volume when the control is first turned,
> and then a
> progressively smaller boost as it is rotated further. The
> effect is to make
> the actual perceived volume appear to coincide with the knob
> rotation.
> Thus, with an audio taper, turning the control, say 45
> degrees, changes the
> _perceived_ audio volume by the same amount, no matter
> whether the starting
> volume is low or high..
>
> By contrast, with a linear taper, the control seems to have
> very little
> effect when first turned, and then progressively greater
> effect at higher
> volumes. With the Orion, turning the control the first 90
> degrees (1/4
> revolution) from zero audio produces very little increase in
> volume. Although some may prefer this audio "bandspread" at
> low settings,
> for most users it is a nuisance, since it makes it difficult
> to quickly
> turn the volume up or down. The accepted convention is that
> a 300 degree
> turn of the volume contral spans the range of zero to maximum
> audio. (With
> encoder volume controls, which lack a mechanical stop, this is often
> increased to 360 degrees.) For the Orion, the span is 540
> degrees ( 1.5
> full revolutions), which I believe to be excessive. When this
> unusally
> large span is added to the linear taper, it makes the audio
> encoders seem
> very unresponsive.
>
> It is a bit more difficult to implement an audio taper wihen a volume
> control is a rotary encoder instead of a potentiometer, since
> an encoder
> has inherently a linear output (a constant number of pulses
> per degree of
> rotation.). However, doing so is common practice. For
> example, the radio
> in my Infiniti FX-45 uses an encoder for the volume control.
> The first
> quarter turn (90 degrees) raises the volume to a comfortable
> listening
> level. The next quarter turn increases it to a loud volume,
> and the next
> quarter turn blasts your socks off. This audio taper is
> accomplished in the
> radio's firmware, which essentially duplicates the response of a
> conventional audio potentiometer.
>
> I believe that implementing an audio taper in the Orion
> volume controls
> would make the radio seem more natural to use. It would also
> make it easier
> to turn the volume up or down quickly. Admittedly, this is
> not a big issue,
> but I think making the needed firmware change would be one step in
> addressing some of the "fit and finish" issues of the Orion,
> vis-a-vis its
> Japanese competitors.
>
> 73,
> Jim Garland W8ZR
>
>
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