[Orion] Re: Orion Digest, Vol 4, Issue 8

[roger]

Probably what brought this about was the fact that most all of the Ten Tec
gear that I have owned would go from low volume to intolerable loud volume
in the first 4 to 5 degrees of turn on the AF volume control. This is tough
on the ears at times when wearing earphones.  I have spent 30 years pulling
out the soldering iron and going to the parts house for parts to Modify
rigs, Now that I do not have the patience, eyesite or steadyness of hand
that I once had it makes software updates more attractive.
KO4O
----- Original Message -----
From: <orion-request at contesting.com>
To: <orion at contesting.com>
Sent: Tuesday, January 20, 2004 11:00
Subject: Orion Digest, Vol 4, Issue 8


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>    1. Orion audio gain controls (James C. Garland)
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> ----------------------------------------------------------------------
>
> Date: Tue, 20 Jan 2004 07:43:25 -0500
> From: "James C. Garland" <4cx250b at muohio.edu>
> To: orion at contesting.com, tentec at contesting.com
> Subject: [Orion] Orion audio gain controls
> Message-ID: <5.1.0.14.2.20040120070345.01d86a58 at admin.muohio.edu>
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> 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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> End of Orion Digest, Vol 4, Issue 8
> ***********************************
>