Receive Audio Quality and Control

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w2zs

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Audio Quality and Control

Most scanners and ham radios have mediocre speakers and audio amps. For example my 2 ICOM HF Ham rigs have 3 watt audio amps with 10% Total Harmonic distortion (10% THD). With speakers facing upward, the resulting audio can leave a lot to be desired. Many scanners have the same configuration. I wanted to see if I could improve the quality, readability and flexibility of my radios audio, after all radio is all about sound! With a bit of advice from Bob Heil (Heil sound makes both pro and amateur radio audio equipment), the following is what I came up with.

I already owned a pair of good quality bookshelf speakers so I connected them to the radio’s speaker out. Just having the speakers, facing you at ear level, was a significant improvement. This is the lowest cost way to improve your audio. One problem is that you’re still using the mediocre audio amp built into the radio. Another problem is add in a couple more speakers for 2 scanners and the desk is getting pretty crowded. How if your rig has a line out (line level out) you can bypass the internal amp and get some real flexibility with multiple radios to boot and you only need 2 speakers. Hams may have to wire up a DIN plug to get to line level audio.

First you’re going to need an audio mixer, I picked a Behringer Q1202, but there are lots of models to pick from. They look more complicated than they really are. Check out YouTube for how to use a mixer. Second you’re going to want a pair of Powered Studio Monitors. Studio monitors because their built in amps and speakers are matched to produce a very flat, very low distortion audio, at least 10 times better THD than the one likely built into your radio and many times the output power too. I chose PreSonus Eris Series E5 speakers because they are RF shielded, as a ham, an important consideration.

How connect the line out (probably a 1/8 plug) from your radio to one of the channels of your mixer (1/4 plug). Connect your speakers to the mixer (1/4 plug for the mixer to whatever kind of connector your speaker uses. You’re ready to listen.

The beauty of this set up is not just better quality audio, the mixer provides great flexibility for those of us with multiple radios. I usually listen to HF audio on my right side speaker and scanner on the left, but you can easily have 2 audio streams on one speaker, at different volumes if you like, or both speakers on one stream, well actually any combination you can think of can be produced.

Unbalanced, Balanced TRS, TS, and XLR what does it all mean. The audio we all use in home system is moved around on unbalanced 2 wire connections. “Pro” audio prefers to us a balanced 3 wire system, 2 for the signal 1 for ground. Balanced helps eliminate hum, so if you’re a ham I suggest you use studio monitors that accept the 3 wire system to avoid RFI. If you’re just hooking up receivers unbalanced 2 wire is fine. TS is shorthand for Tip and Sleeve 2 wire connector. TRS is shorthand for Tip Ring and Sleeve 3 wire connectors, Both TS and TRS are 1/4 plugs.. XLR is another type of 3 wire connector common on "pro" audio gear.

Sites I found helpful: Zzound.com and sweetwater.com, both carry tons of audio equipment, new (sometimes used too) plus info on how it all works.
 

Chance

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Thank you for the excellent post. I started getting the idea about using a mixer and it's great to see a post confirming my line of thinking and giving me a few other ideas.

Chance
 
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