What de heck iz it?

radio spectrum

ESSB can mean two things. Extended Single Side Band or Enhanced Single Side Band.

Single side band refers to the most common mode of voice operations on the ham bands. It’s a whole long story explaining what that means so I’ll let Wikipedia do that.

Extended refers to having an audio passband and overall signal bandwidth 4kHz and wider. Basically guys can make a SSB signal sound like AM radio broadcast quality. In deference to other operators on the bands, I don’t operate that wide as the wider a station is, the more likely it is that they can interfere with another user. It also starts to really encroach on the concept of efficient sharing of the radio spectrum that is available. Narrower means that more people can operate in the same space.

Enhanced refers to doing what one can to enhance a more normal width signal of 3kHz or narrower. This is where I play around.

Basically if you spend a long time in a conversation with someone, it is to both of your benefits to sound as clean and as good as you can to make listening easier and more comfortable. With some knowledge and practice, audio processing of varying types can be applied very nicely to ham radio transmit audio.

There is one pre-requisite to all of this.  You must have a rig that will actually pass the bandwidth you desire to transmit or all the processing in the world won’t change your audio.  You have to have an idea of what you are trying to achieve and then the equipment you need to get there.

In my setup currently I have various microphones for different properties that they have and some ‘outboard’ audio processing gear that I connect my ‘audio chain’ through before the signal meets my transmitter. Audio chain refers to the signal path of equipment before it hits the microphone jack on the radio.

Equipment that I run or have run in my quest for experimentation with audio profiles for transmit.

  • CAD M177 - Low-end studio condenser microphone.  Excellent detail and natural response due to very high sensitivity is the strong suit for this one.
  • Studio style microphone boom - Makes moving around much simpler and clears off the desktop for other clutter.
  • Audix OM2 - Low-end hypercardiod (very narrow pickup pattern) dynamic microphone.  Looks like any vocal mic you have seen someone singing into on stage.  Excellent background noise reduction is the best property of this one.
  • Joe Meek 3Q - Low-end compact studio mic pre-amp and compressor.  Works very nicely on voice, but doesn’t have a noise gate so when dialed in, it can tend to bring in background noises that are distracting and unwanted.  Needs a gate paired with it.
  • Symetrix 528e - An all in one voice channel processor.  Contains a mic pre-amp, de-esser, downward expander (noise reduction), compressor (makes the level even and appear ‘louder’), three band fully parametric EQ to contour the frequency response.  I love this thing…it’s amazing.
  • Edirol FA-66 - Pro audio - firewire soundcard to use the computer and software based processing like the Voice Shaper software.  This worked very well but required the computer to be up and running with Windows to use my radios, so I sold it recently.

The biggest advantages to what I’m using over a plain ‘stock’ microphone are that I have a powerful EQ that allows me to clean up any issues in my own voice or the room noise where I’m operating.  This alone can transform the overall character of the audio drastically.

I also run a downward expander that is pretty much like an automatic volume knob that reacts quickly and smoothly, lowering the volume level or ‘gain’ of th e microphone between syllables.  This keeps everything quiet when I’m not actually talking and makes the signal sound a lot cleaner and more professional.  I can have family members having conversations nearby that will never be heard over the air….which can be a very good thing :-).

Next up is the compression.  Compression is the inside-out of the downward expander.  It too is an automatic leveling control but it is in effect WHILE I’m actually talking.  It ensures the signal level is uniform.  There are a few variables to configure, but the simplest explanation is, that it will close in the difference between a whisper and a shout.  Applied in a heavy handed manner, you would hear a whisper at the same volume level as a shout.  This makes the overall signal ‘feel’ louder and with SSB transmissions this is an incredibly powerful tool to make your signal more effective.

With all of the processing above, my voice signal can sound a bit too ‘dry’ or ‘dead’  like talking inside a fully packed closet full of clothing.  To space it out a tiny bit and make it once again feel natural, I also apply just a light bit of plate style reverb.  The tricky part there is to make it subtle so it sounds natural and not like you have your head inside a bathroom or a bucket while you are talking.

Is this for everyone?  No way.  There are lists of reasons why people despise this practice and you can surely have conversations with people with the microphone that came in your original radio’s box.

Is this fun to play around with?  You bet.  I worked as a sound engineer working in local clubs and touring around the country for about five years.  So for me, this was a natural progression once I got into the hobby.

My best advice is to listen to those who have already done all the leg work for you and make decisions on your approach and equipment based on that information.  It will save you lots of hassles.  The next best piece is to be sure to be able to monitor your actual transmit audio in some form or another as trusting a radio’s own monitor circuit seldom yields good results.  Do transmit for days into a dummy load talking to yourself and Do use a receiver with a wide enough bandwidth to hear your whole signal.  Above all else, have fun….if any part of this hobby gets under your skin, put it away for later or move on…we only do this for fun….right?

Some very helpful sites.

NU9N’s Site A very well done site discussing the radios and hardware available and the actual application of the processing.

W2IHY Julius Jones He sells some great gear for those who want things to ‘just work’ with their ham specific audio enhancement.  This can be a much better route for those less initiated or patient in learning the nuances of using processing gear.

Sweetwater Sound A great on line source for pro-audio equipment.

B&H Photo and Video Another great on line vendor of pro-audio equipment.

I have no interest in any of these vendors’ businesses other than the fact that they have provided me consistently excellent service over the course of many transactions.