Re: Flat Audio - Motorola
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Even in Flat audio mode, the TX side begins to hard rolloff at about 2600 hz.?? At 3000 you're down 3db and it drops quickly from there.? No external filters are needed.?? It's flat from 20-2600.
Andy WJ9J
I've discovered that the RKR1225 / Specta series radio RSS setting allows you to select "post" or "pre" limiting for the TX audio path for flat inputs on the accessory port.?
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Not familiar with the spectrum radios. Where is the cap? In series with the TX audio input to the transmitter?
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Also worth noting, and I've found a ton of conflicting information on the site regarding flat TX audio with these radios, you must use pin 5 on the accessory port for TX audio if you expect to have flat audio. Pin 2 is commonly suggested to be used for speech or normal audio from a controller. However, the audio out of the transmitter is pre-emph'd regardless of the "TX Flat Audio Input" setting. I mistakenly thought that setting it to post (not "pre) meant no pre-emphassis on any TX input on the accessory port. This is not the case. If you use pin 2 it's Pre-emph'd period!.?
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I've moved over to using pin 5 with the RSS External Accessory menu item "TX Flat Audio Input" set to "pre". Not seeing any overshoot or excessive deviation at higher frequencies. I'll double-check again today.
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Thanks for your suggestion!
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Jim? ??
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