Well, after running the external proc for a couple of weeks, now, I'm getting the hang of what this thing can do and what it shouldn't do. I must say I'm quite pleased with the reports I'm getting.
One of the things I've discovered, is the value of the expansion and noise gate ability. In fact I've come to think it's critical for a good signal. To explain this, however, I've got to dive into the settings I'm using, and the working philosophy behind them.
Remember that the goal here is raising the average RF power levels by several DB without adding any undue distortion. Understand what I mean, here. I'm not the audio purist in ham radio some operators are. I'm willing to deal with a bit of added distortion to a certain point, so long as I get the advantages of the increased audio level/RF level.
So, here's a quick overview.
- Whatever mic I'm using. (Usually a Hiel pro-set 6 headset.)
- Gemini mix console with EQ to bring things to line level
- The Behringer Composer Pro-XL MDX2600
- Optimus 10 band EQ set to pass 100-3000Hz with a 3db push at ~2100Hz.
- Pyle breakout box with a pad to distribute the audio to a second console for recording conversations and to bring the audio back to microphone levels for the radio.
The 2600 Pro is a a broadband Noise Gate/ Compressor / Limiter/ De-esser and is the star of this show.... It is a Stereo unit. but I'm not using it that way. I have the two channels, left and right, running in series, each one running independently. . In other words, the audio comes out of the mixer and runs to the left channel as the first stage of level control.
This first stage (which if you like to think of it as such, is the left channel) is set up with a full-on noise gate which opens up at seeing anything on the inputs above about 15db down. This keeps stray noises from being broadcast and helps keep the radio's vox control in line. Once it gets over that threshold, it goes directly to the compressor, with about a four to one ratio.... a slow attack and a slow release. The De-Esser is set fairly loose, only acting if it sees a very serious peak of higher frequency content. Remember, I'm trying to keep the audio bright with the input EQ leaning very heavy on 2100Hz, , but at the same time you need to keep it under some modicum of bandwidth control. So, the I have the De esser acting in peak mode, which over-rides the slower settings.
The second stage is the right channel. I'm running the audio directly out of the left channel output to the right channel input, with the system set in "dual Mono" mode. The two channels' level controls operate independently, one from the other. This "side", I have set as a pure peak limiter, with the rise and fall times set very fast indeed, including perhaps 8db worth of noise gating here. This helps provide a bit of definition between words.
This setup theoretically would allow me to run twice the compression... but that's not the purpose here. Rather, doing it this way allows me to run two separate compression and expansion curves.... the first fairly slow AGC/Noise gate and the second very fast peak limiter/expander.
The purpose of the peak limiter is obvious.... it's maintaining very tight control over any peaks directed at the radio. With the expanders (noise gates) disabled, my peak to average ratio on my air is about 2 or three DB... no more. (If you're looking at a VU meter, that would be the difference between 80% and 100% Or if you like we're talking about less than a half an S-Unit of received signal between the room ambience and my voice.) That would mean, absent the noise limiting, that I'd be picking up massive amounts of unwanted signal from the room. Echoes, fan noise, etc. I also have employed the de-esser here as well, which seems to help in keeping the bandwidth inside the 2800 Hz wide skirt. (100-2900)
But here's the secret: As long as my normal speech is above the threshold of the noise gates, the audio goes directly to as close to zero DB as no matter. Below that level, the noise is unheard, as is the echo, my breathing, and so on. No wasted watts, no clutter on the signal.
I'm getting amazing reports and I am busting through pileups with little effort, even on those occasions I've run with with RF power levels reduced. From this, I learn two things;
- With the power on full, I'm getting an average power I'd never be able to achieve without the external processor.
- Even at lower RF power settings, I'm being heard, apparently due to the distinctive nature of the audio.
Both of these factors make a huge difference between my being heard or simply being buried in the noise. And, being heard is the whole point.
No comments:
Post a Comment