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This is why I laugh at people using super expensive mics on CB and Ham

Onelasttime

Sr. Member
Aug 3, 2011
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Now do keep in mind that we are talking about using a mic that will match or exceed the audio bandwidth of the radio not what is best for use in a studio or recording music or voice overs! $20 mic vs $12,000.00 mic. Yes clearly you can hear a difference in this video but do keep in mind we are talking primarily about CB radio use and secondarily amateur radio use. This is why a cheap $20 or less electret condenser mic and some sort of eq/preamp can sound killer direct injected into a radio. This is why you do not need a $150, $250, $400, $700, $1200 mic for CB or Amateur radio! If going through the actual mic jack/connector through the audio signal path, amc and filtering will reduce the effect of anything you do. If you look at this through the filter of two way radio not recording studio you can really see how incredible that cheap $20 mic sounds for two way radio use only. I suspect that one could take the $20 mic apart and by swaping out cap values and types one could tune it a lot. No way a copper sputtered diaphragm is going to match a gold sputtered diaphragm or other exotic metal. Keep in mind how many radio's today have rather limited audio out of the box between 800-2500 and if you are lucky 250-3000. That would be the -3db down at each end.

 
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I know of a local ham operator who has an old cobra138 that he uses from time to time with an old Cobra Mic. That radio sounds to me at least, just as good as his ham equipment with all the enhancements. I think some guys just like having all the extra toys to play with.
 
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All about toys, and bragging how they direct inject outboard audio equipment.

Downsize is only a few I have heard actually got it to sound decent most sound garbled as if they trying to squeeze 5lb of chit into a 2 lb box.

But as long as they enjoy all the extra knobs to adjust and they are having fun is all that matters, to hell with what it sounds like on the air or all the splattering they are causing on the bands.
 
An expensive mic is the last thing you should buy to sound good. Once you get to a certain point and want to improve even more maybe its time to buy something of better quality. Some people never learn to use the audio gear or can't keep rf out if it. Their desire to constantly screw with knobs or make the watt meter swing keeps them sounding shitty and a $400 mic won't fix it. Unfortunately they make all of us with an external audio chain look bad to others.

One positive thing I have witnessed from a few people getting into wideband AM on the CB is that they had to start playing by the rules to get the good sound they wanted. Sure they are running wider audio bandwidth now but since they bought a modulation monitor or scope and have quit beating watts out of little amplifiers they actually occupy less bandwidth.
 
Fancy microphones with a stock tune is rarely beneficial.
Drastic radio modifications are needed to get the Heil PR781 to perform flawlessly on cb and export radios.
People's reactions to the perfect audio from a cheap Chinese radio are priceless.
Most folks should stick with whatever is most intelligible and call it good.
 
I'll disagree.

I agree that keeping RF out is important. But using a good mic has many benefits. There is a learning curve to using a preamp/compressor/eq/audio xformer that frankly is out of the comprehension of many operators. For those ops that firmly believe that yanking out the limiter and cranking up the mic gain is everything; there is little hope. But some break thru and get it right. When they do, they can sound superb w/o distortion or clipping limiters.

First off, you don't need an uppity mic. Any large diaphragm condenser will work fine, so will a decent dynamic or even a ribbon mic (more expensive/exotic/fragile - but can yield v.good results too). ~$100-$200/used would be more than sufficient.

What these mics offer in a limited and/or slightly expanded audio bandwidth modified radio is clarity, accuracy, and honesty. You can sound natural. Intelligibility is increased.

In comparison to your best base mics with crappy. distorted, and very noisy internal preamps, the difference is often dramatic when done right with a real mic. Many 'communication' or even hot mics do NOT have a flat freq response (anything but); they are peaky in certain parts of the usable range. Like I said, there is a learning curve to it.

Guarantee ya the next solar cycle will have more stations doing this than the last cycle. Some have gotten hip to it.

Laugh on . . .
 
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I think the first thing you need if you want to play with improving your audio is the ability to accurately monitor what you're transmitting, something like an SDR would give a good idea of what you're actually putting on the air. Then once you know where you are now you can choose your equipment to get you where you want to be. It may be a better mic or it may be something else, you won't know if you don't know what you sound like now.
 
The first mic i used when I started dabbling in this was a shure sv100. It was a $20 karaoke mic and was a definite improvement over the typical cb microphone. I still use that mic on one of my rigs with no external gear. It sounded better to me than the mc-60 did so I put the shure on the mc-60 base.

An akg condenser replaced the shure for a few years and now I use a pr40. A person needs to consider the environment they use the mic in before buying one. The main reason for switching to the heil was the rejection off the back and sides. The condenser picked up every noise in the shack.

Monitoring yourself is a big one. Listening to yourself in real time helps but to really fine tune I to listen to a good recording of my demodulated audio. An rea modulation monitor works well for that. Don't forget the dummy load. :whistle:
 
Although it is currently not hooked up, I have been told many times that my old Heath DX-60B transmitter which is quite wide, sounds superb with my Seinheisser MD-421 microphone. I was given the mic many years ago after it fell off stage and no longer worked. All it was was a broken wire inside. The MD-421 has a five position rotary switch on the end by the XLR connector that selects the degree of bass roll-off. It works great for either punching thru the noise or for nice wideband rag chewing. I increased the series pass capacitors values in the modulator stage and that was it other than the microphone. I hope to hook it all back up again in time for this winter.


MD-421 frequency response showing the five different roll-off settings.
730536d1520606528-md421-ii-five-position-bass-roll-off-switch-what-frequencies-does-cut-md421-ii-frequency.jpg
 
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Brings up another interesting point - Carloid versus Omnidirectional.

Where do you want to go today? Only your voice, or something that picks up everything around you - including but not limited to, your shoe...

When at home, all alone - with you and your microphone...

Carloid OR Omni is the way...

Carloid - for "Heavens To Megatroids" Emarassing you with Jetsons' playing in the background for the kids'...

Omni - for the moments of "itchin' in the Kitchen" when you and your cat, is where it's at...

First decide pickup pattern.

Second - find Element / Diaphragm mix that brings out the "Hellmans" in your voice...

(Hellmans? Oh, sorry...)

Food_Channel=Off
No_Picnic = On.
Ham = On + 5
Mayo = Hold

Then decide whether to...

Open bandwidth of mic Amp internally in radio - widen bandpass thru to Final (Class D or Low-level)

Buy Pre-amp Mic-amp and fiddle with it until you find the right bandpass that matches voice to radio - coupled the best...

A little of both...

Welcome to the Forum.

:+> Andy <+:
 
First off the word is "cardioid" not "carloid" and I can see no reason why anyone would want an omnidirectional microphone for communications use. Sound quality and frequency response are what counts and that can be the same with either an omnidirectional microphone or a cardioid microphone. I want my voice to be heard not the fan in my amp or the television in the living room or the microwave running in the kitchen or the washer running in the porch. This is the polar plot of the Seinheisser MD-421 as well as the frequency response. The plot is symetrical down the middle. It just looks odd because of the bass notes being depicted on the left while the highs are on the right.

md421-ii_freq_response.jpg
 
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First off the word is "cardioid" not "carloid" and I can see no reason why anyone would want an omnidirectional microphone for communications use. Sound quality and frequency response are what counts and that can be the same with either an omnidirectional microphone or a cardioid microphone. I want my voice to be heard not the fan in my amp or the television in the living room or the microwave running in the kitchen or the washer running in the porch. This is the polar plot of the Seinheisser MD-421 as well as the frequency response. The plot is symetrical down the middle. It just looks odd because of the bass notes being depicted on the left while the highs are on the right.

md421-ii_freq_response.jpg

I agree with most of that. My point was that you do not need a super expensive mic for 2 way radio communication. The real problem is one of finding an affordable mic no matter if it is dynamic or electret that does what needs doing! LOL Obviously background noise is a very real issue in communication. The mic is not to blame nor it's pattern for noise in the background that is about setting up your shack correctly. It ultimately comes down to knowing your gear and your environment and setting things up to work best for you. I do not watch tv while I am on the radio and I do not attempt to listen to 5 radio's at once and a scanner and I do not have toddlers running around when I am on the radio either.

The one downside to all the EV com mics I own is that you have to eat the mic to be heard and that is almost as bad as the other extreme.
 

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