[Elecraft] K3 : SSB modulation

[Jim Brown]

On Thu, 19 Aug 2010 23:16:38 +0200, Laurent HAAS - F6FVY wrote:

>We spent time on various available settings (mic gain, compressor 
level, 
>etc), with no luck, excepted a very distorted and awful audio to 
roughly 
>reach the same level, which is not acceptable.

Hi Guys, 

I regularly get reports of having very good sounding, very competitive 
contest audio. 

My method is VERY simple. 

1) I set TXEQ to roll off (reduce the strength of) the three lowest 
frequency bands to the lowest setting (-16dB). 

2) I set Mic Gain as described in the K3 manual. 

3) I set Compression for 10dB on peaks as indicated on the CMP meter. 

4) I have another contester with good ears (usually the Locust, K6VVA) 
listen to me with his receiver set for wide audio bandwidth (that is, a 
wide filter), and tweak TXEQ based on what he tells me. Some mics and 
voices may sound better with a LITTLE boost (3-4 dB) in the highest 
bands (#7, #8), and some may sound better with some CUT in the 4th band 
(to reduce lows). 

An important part of contest audio is playback of messages from the 
computer. Computer sound cards can produce very nasty, muddy audio with 
no punch if they are overdriven (too much mic gain for the recording) 
and too much playback level. 

When recording messages, make sure that you are not overloading the 
sound card or producing digital distortion by setting mic gain too high. 
When recording messages, plug headphones into the computer and listen to 
the audio you have recorded. Does it sound clean? If not, turn down the 
mic gain until it does.  

When playing back messages, set the playback gain fairly low, set the K3 
Line Input to about 10, and gradually turn up the playback gain of the 
computer until ALC and Compression, as indicated on the K3 meters, 
matches your live mic. 

Hope this helps.

73, Jim Brown K9YC