MIC STUDIO SOUND GURU NEEDED

[darticus]

We need info from the guru on our site on how to add studio sound to our CBs. I have a Shure SM57 mic and through a mixer or sound effects device should give me some great sound. Is there someone that can give some suggestion on how to do this. Want to use on my Galaxy 2547. Thanks Ron

[k3cfc]

Originally Posted by darticus

We need info from the guru on our site on how to add studio sound to our CBs. I have a Shure SM57 mic and through a mixer or sound effects device should give me some great sound. Is there someone that can give some suggestion on how to do this. Want to use on my Galaxy 2547. Thanks Ron

I take it you DID NOT read my last email.

K3CFC

[prcguy]

Stock CB mics usually have a lot of mid range peak and an SM57 will sound very bland without some equalization. A Shure SM57 is fairly flat across much of the voice range with a little rise above 2Kc and a peak around 6Kc, which will not be heard on many if any CBs..

Probably the easiest way to make it sound good on a CB is a W2IHY equalizer which is designed to interface with radios and is not very prone to RFI. Do a search on eBay, the 8 band version can sometimes be had for about $75.
prcguy

[prcguy]

After thinking about this for a few minutes I'll take back my recommendation of the W2IHY box and here is why.

On several amateur radios I've interfaced some fairly expensive condenser recording mics from Groove Tubes, a Heil PR-40, Shure SM-58, an expensive ribbon mic and some other mics I can't remember using a W2IHY box, some outboard recording mic preamps, compressor/limiters, etc. I also used a high quality receiver with wide IF for setup and a recording engineer friend who knows my voice and was patient enough to tweak everything in.

Depending on who I was talking to and what kind of radio they had I got lots of different comments ranging from fantastic to way too bassy if they had a narrow receive filter that did not allow the high frequency content to pass through their radio. Its interesting the well known late night radio host Art Bell commented on my radio sound and said I had finally arrived, which was a nice complement.

In the end, a stock Shure 526T amplified CB microphone with no outboard gear got the most consistent complements from everyone. You can spend a lot of money and time and probably learn a lot about audio equipment setup but I would recommend buying a Shure 526T and be done with it. They also sound exactly the same on every radio and I have used them on probably a dozen or more HF radios.
prcguy

Originally Posted by prcguy

Stock CB mics usually have a lot of mid range peak and an SM57 will sound very bland without some equalization. A Shure SM57 is fairly flat across much of the voice range with a little rise above 2Kc and a peak around 6Kc, which will not be heard on many if any CBs..

Probably the easiest way to make it sound good on a CB is a W2IHY equalizer which is designed to interface with radios and is not very prone to RFI. Do a search on eBay, the 8 band version can sometimes be had for about $75.
prcguy

[darticus]

I have the SM57 so that would be what I would like to try first. I'm thinking mic to equalizer to sounds effects to radio. But how would it be wired to a 4 pin galaxy or 4 pin cobra radio plug. If there are only 2 wires coming out of the effects unit or eq? Thanks Ron

[darticus]

What email??? Send again! Ron

Originally Posted by k3cfc

I take it you DID NOT read my last email.

K3CFC

[WJYSTV62]

Please don't use sound effects. They just add distortion and annoy people. Echo does not make you more legible, it reduces your articulation. Distortion wastes power. I highly recommend the gentle use of compression and peak limiting. CB radios are not designed (they legally cannot be) for very high average modulation without distortion. CB is AM and in AM modulation is everything. A higher average modulation helps cut through the clutter.
Equalization can be helpful but it isn't everything. The audio bandwidth of CB is small and that microphone can do a lot more. It has a rise in the response intended to improve articulation but it is arguably in the wrong frequency range. A lot of bass is a waste of power. On the receiving end it's unlikely they will hear anything below 300Hz either due to the speaker or the circuitry or both. There's no point in transmitting anything there and many radios filter that out inside anyway. A more narrow bandwidth equals more power for the remaining frequencies but reduces articulation.
Be sure the radio is properly tuned up. If you look at the CB spectrum on an analyzer you'll quickly see dozens of people trying to talk to each other and not one of them is on frequency.
Many modern CBs are designed for their stock electret condenser mics. That poses a problem when connecting to a dynamic mic or to a mixer. If there's DC on the mic wires, and there may be, you can permanently damage a dynamic mic like the SM57. It's important to know exactly how to interface to the radio. A multi-pin connector is used for connections for the mic and for the push-to-talk switch. You'll have to know which pin is which. Remember if you add a mic and mixer you will also have to add a key.