[Orion] RE: [TenTec] Orion audio gain controls

[Dick Green]

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 at muohio.edu] 
> Sent: Tuesday, January 20, 2004 7:43 AM
> To: orion at contesting.com; tentec at 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
> 
>