Connecting CB Radio and Pro Audio --- How it's done

[Foxhunter]

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Here's a post asking about the use of Pro Audio studio equipment and use with basically a common CB radio.
11 Meter CB Radio / Sound and Microphone Audio Mixers / EQ Equalizers / Sound Processing / Studio Equipment / Broadcast Audio / HiFi High Fidelity / Special Effects



The main question in a nut shell is, "how is it actually done ?"


Assuming you've gone the distance already and spent some money on say a studio mixing board, a mic preamp, a high-quality microphone and mic boom, a footswitch----and jeez, what else ? Some of the following some of you might have at one point wondered also or even for a moment when surfing the web thought "I wonder if I could use that with my CB?". These are some basic questions from the average person who hasn't spent time around a recording studio. When I was a club bouncer, I did DJ some nights in a busy hip-hop nightclub, filling in for the regular DJ whenever he wanted to leave early with a girl usually etc. But that's the extent of my commercial audio experience---not all that much, but maybe a few nights more than most guys. What fun!



Physically hooking up your CB radio to a Mixer Equalizer


First and obviously, right away, the first thing that comes to mind for me is, "Hey, there's no audio Input/Output RCA jacks on my radio", from the factory at least. Of course we all know that, and yet I'm sure many have wondered------"how exactly do they do it ?"


What's a basic "shopping list" of things to get for accessories ?


The only "extra" jacks I have on a few of my better radios are for: Phones, CW key, PA, Record, and Frequency Counter


If indeed that's what's needed to be installed, to run a radio into a mixing board, what is typically done ? I'm assuming that's the case and I/O jacks are used, but certainly I don't see many shops offering this service. A little out of the ordinary.


Or, what type of adaptor is needed to run a mic straight to a mixer and/or EQ ? A mic with a 1/4-inch phone plug ? Then back out of the EQ and put the normal 4-pin on the end going into the radio ?


Is it done that way instead, via the mic and mic cables ?


Basically, what has to be "done" to the radio ? Also, "where" does it need to be done, what part of the audio signal chain internally (if) ?


Are Line-In/Line-Out (or Audio-In/Audio-Out) jacks installed on the radio and then commonly used to join the radio to the mixer ?


Or, is the link accomplished purely through the mic and mic cord ?


Does the mic go into the mixer or equalizer, get processed, then simply corded back and into the radio's mic jack ? That would be simple.


What is the typical "chain" component order ? (Ex. with a typical simple mobile setup: Radio--->Amplifier--->Meter---->Antenna)


Now here's another question, even if you do make a compatible connection from your radio into the mixer, adjust the sound audio to your liking, then what ?


How does your mixed or processed audio get reintroduced back into the chain again ? Does it go back into the radio, then get transmitted out and into the airwaves ?



Asking Questions, what about you ?


I really don't mind asking the basic questions and don't pretend to know more than I do. But really, everyone has their strong areas and weaker ones. But in this one ARENA particularly, most of the guys seem to be unacquainted with studio sound and putting CB "into the mix-er" (pun intended). And I ask the straightforward questions as to leave no basic stone unturned in a sense, although I'm sure there are even more questions to be posed maybe. There is someone near me who does this, but his lips are sealed. I know of two other CBRT members who are/were doing this type of thing, but they don't seem to be active lately or even for some time now.


It'd be nice to see some of this answered in layman's terms and not too vague. In the end I'm sure I could go to someone in the area and pay to have it done or explained, but it'd be nice to see a thread where some guys explain this subject clearly and in some detail. We have lengthy lengthy threads about Imax antennas and Palomar amplifiers and 102-whip antennas etc---what about real audio equipment ? Definitely all ears. And I could use some help from others asking some good questions too, besides just me.


73's and 5-over-9
Foxhunter 351 NJ


Here is a link to a semi-related thread on "Good Mic Audio" from a little while back for good reading and review. I just posted a new article excerpt there. Check it out!

Microphones: Vintage Studio Audio Broadcast Music Paging
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['Doc]

How about,
Mic to 'mixer' input, 'mixer' output to mic jack on radio. Adjust to suit taste.
- 'Doc

[Foxhunter]

How about,
Mic to 'mixer' input, 'mixer' output to mic jack on radio. Adjust to suit taste.
- 'Doc

Or, what type of adaptor is needed to run a mic straight to a mixer and/or EQ ? A mic with a 1/4-inch phone plug ? Then back out of the EQ and put the normal 4-pin on the end going into the radio ?

So Doc, that's kind of "too easy" or simplistic of an answer in less than 20 words, isn't it ? Thanks I appreciate the reply and input. I don't think any offense was intended, but I was kind of afraid I'd get short/vague/simplisitc answers when posting a thread on this subject.


No worries, I'll still ask the stupid questions, I don't mind. And if what's posted above is all that needs to be done, then I seriously have "overthought" it, and basically a 1st-grader could have told how it should be done.


Like Doc mentioned, as well as similarly what I quoted from my post above also, that's one scenario, sort of a simple one at that. But is that really "all there is to it" ? Boy I guess those studio guys are waaay overpaid.


I'd "assume" (you know what that "spells" out right?) that a "typical" 4-5-6-or-8 pin CB or Ham mic, that many of us are using, needs to be adapted over to 1/4-inch phone for EQ/Mixer input, or 3-pin XLR.


Gee, I wonder what the impedance is at/going into the mixer ? Does an impedance matching device or line transformer need to be placed between the mic and the mixer ? Or, what about the mic/audio Line-Out of the EQ, going back into the radio ? What would be the impedance there in the line exiting the EQ ? Does another matcher need again to be placed there, to transform it back to typical CB mic impedance for the radio input ?


Maybe a EQ/Mixer has an adjustable impedance setting control, hopefully on both I/O sides, but I doubt both, but it's possible.


Or, using an external line impedance transformer, the mic impedance has to be stepped up/down going into the EQ/Mixer to make it happy, the audio gets processed, then exiting the mixer the impedance needs to be stepped up/down again, for the CB radio mic jack input to make the CB happy.


Where does a mic preamp enter into the scheme ? After the EQ, right before the radio correct ?


How does "keying" the mic affect the the system as a whole. Afterall, that's an awfully long sequence-chain all along before actually entering the CB mic jack, interupted by several components before finally entering the radio (sginal insertion loss etc).






For someone, anyone----for any of our CBRT Members here at all----seriously thinking about heavily investing in some basic Pro Audio gear (afterall none of it's cheap), some more detailed and explanitive answers would be nice.

Afterall-----It's not like I'm asking whether to go with an "Astatic 636 or a RoadKing 56" hand mic! It seems like those type posts always get the most answers and replies, doesn't it ? I'll give the thread a little time and see if anyone has something interesting and more to say. Thank you.



Foxhunter 351 NJ

[TwentyTwo-Zero]

You have the right idea, Foxhunter. The options as far as the mic, eq, mixer, noise gate, etc, you choose is personal preference. Wiring it up offers a couple different options. I prefer to utilize a balanced audio signal up to the point of injecting the signal into the radio. Others will use an unbalanced audio signal throughout. Both methods will work, but the balanced signal offers protection against hum and rf interference - the unbalanced signal doesn't. The mic you select will determine if you need to provide power to the element or not, so if it is required make sure the preamp/mixer you select has a phantom power option (most do). Here's a basic/generic setup: The microphone output is connected to the preamp input with a (balanced) XLR to XLR cable. The preamp output is connected to the mixer input with an XLR to XLR cable. The output of the mixer goes to the microphone input of the radio with an XLR to Foster plug. This is the point where you convert the balanced audio signal to unbalanced, and wire in your PTT switch. The audio + wire (pin 2 of XLR plug) is connected to the 'audio' pin of the Foster plug. The shield (pin 1 of XLR plug) and the audio - (pin 3 of XLR plug) get connected to the common (shield) pin of the Foster plug. Now, using a piece of single conductor shielded cable connect the shield to the common (shield) pin of the Foster plug and the center conductor to the 'ptt/transmit' pin of the Foster plug. Depending on the size of cable used you may/may not have to use a rat tail file (or dremel tool) to enlarge the opening in the Foster plug so your wires will fit through the strain relief. How you terminate the other end of the cable is up to you. You can solder a momentary N.O. switch directly to it, or put an inline jack on it so you can plug a hand or foot switch into it - lots of options here. If you want to add components to your setup simply add them to the daisy chain with another XLR cable. You can also use the TRS 1/4" (also a balanced signal) or the 1/4" mono (unbalanced) provisions if you want. You would follow the same procedure, but you wouldn't have a shield wire (pin 1 of XLR plug) terminating at the Foster plug. As far as what component goes where in the chain, I haven't seen any 'set in stone' order they should go in. If you use a seperate noise gate, I would put it inline last though. I'm sure I forgot something along the way...if I did maybe someone will mention it...

['Doc]

All well and good if you are dealing with producing 'quality' audio. But you're talking a typical CB radio and AM mode. 99% of that 'quality audio' is wasted. Is this going to be strictly for voice stuff? there goes probably another 1/2 of that remaining 1% of un-wasted quality. Remember, this is 6Khz signal bandwidth here. Oh, what the hell, double it, make it 12 Khz, that just means interfering with two other channels, big deal. If there's some particular need for it, that's one thing. Other wise it's just silliness. Be as silly as you like.
- 'Doc

[Darrin]

This thread would be a thread that a lot of others would also like to learn more about as you can tell that from the number of members who have opened this thread up to read more about it, but with Mr. know it all (Doc) that always seems to have to jump in most every thread and offer his negative attitude and personality that sems to put a holt on most threads through out the Forum as not many people want to get into a **Censored** match with Doc over something that he thinks is Silly stuff to him but maybe not to others. Even the ones that try to ignore his negative comments and try to carry on with the thread he still comes back with more negative Bull sh_t to where eventually the thread comes to a stop.

Yes Doc we get your point in the first Negative comment you have to make in most every thread through out the Forum so you don't have to keep coming back after every other reply with more of your negative Bull Sh_t tell eventually you ruin for the rest of us who may want to learn or know more about. I mean don't you have better things to do with your time beside troll around and express your negative personality in every thread and ruin it for others.

I mean look around the Forum and you will see that there is not a lot of threads that will have more than 6 replies to them when you know there would be more but in those Doc with his Mr. No everything and negative replies always seems to put a holt to what could be a good thread that others may want to know more about but know they don't have a chance with Mr. know it all that only thinks he knows everything but really knows about half of what he thinks he knows.

Take it for what it is worth but it would be nice if some of these threads could carry on to where others could learn more about instead of making it about 50% and stopping short of the full 100% because of Mr. negative. There is not a lot of interesting threads or any threads that have more than 6 replies to them and all those seem to have Mr. negative in them causing them to stop short of what could of been a great thread.

Cotton Mouth.

['Doc]

Cotton Mouth,
Thank you, I take that "Mr. Know It All" as a compliment. As for the negative comments, tell me that I'm always wrong. Did you ever stop to think that maybe one or two of them come from experience? If I'm mistaken, PLEASE prove it to me so that I can apologize and know better.
I'd also like to thank you for the "Mr.Negative". And if you'll do a little thinking about it, you can't have a 'positive' without a 'negative', or nothing happens at all. That's more of a compliment than you'll ever know.
I hope you feel better after that post, I do.
- 'Doc / "Mr. Know It All"/"Mr. Negative"

[BushHog]

With that said and done ,lets get back on topic guys.

[Foxhunter]

Thank you BushHog, unfortunately a problem was occurring already in this thread that I initially tried to ignore, and despite it I went to simply try continue on with the thread. I don't appreciate what appears to be sarcasm in the one first reply post and the mocking nature contained in the second from the same member. There's no need for any of it. End of line.

by W8MW (facetious)
Experimenting with different microphones is a waste of time and not good amateur practice. Too many things can go wrong. Your signal will become distorted, your rig's IMD will increase, you'll become too broad, you’ll sound like a wannabe disc jockey. Amateurs are not qualified to deal with frequency response curves of acoustic transducers, impedance matching,level control and wiring of low level audio circuits. Radio manufacturers know best. Plug in whatever mic came in the box, refer to the manual and be done with it.

Don’t get caught up in this frenzy for better sounding audio. Otherwise intelligent and sane people have this unnatural fixation on better, better, better. That’s silly. Stay with what you’ve got. Don’t sweat the small stuff like tinny sound, breath blasts, handling noise or thuds on make and break of PTT. Use the same philosophy that works in the corporate world where products are not built to be the best they can be, they’re built to be just good enough (JGE). As long as the other station understands what you’re saying, that’s good enough for ham radio.

Don't pay attention to audio reports from people on the air. Nobody out there listens with quality equipment or has educated judgment in evaluating transmit audio. All subjective reports are meaningless. Bell Labs’ Fletcher and Munson were wrong when they studied human response to audio signals in 1933. Telco networks are wrong today with all those stupid PESQ studies for perceptual evaluation of speech quality. Don’t make the same mistakes. Ignore what other people think about your signal. And by all means never attempt to judge it yourself.

That should just about cover it. Do you belive a word of it? I don’t.

73 Mike

Now here's one user, TwentyTwoZero, who's been the first to write something interesting and substantial, for those interested in this area/sector. He is one of 5 I can think of where the use of such equipment comes to mind. I also appreciate the two PM's I still have saved, on Yaesu VX-7R software and programming cables for me that he'd sent. Thank you, a valid post such as this is a very good start. I went and subdivided his post so that I could more easily see his main points made.

You have the right idea, Foxhunter. The options as far as the mic, eq, mixer, noise gate, etc, you choose is personal preference.

• Wiring it up offers a couple different options. I prefer to utilize a balanced audio signal up to the point of injecting the signal into the radio. Others will use an unbalanced audio signal throughout.
• Both methods will work, but the balanced signal offers protection against hum and rf interference - the unbalanced signal doesn't.
• The mic you select will determine if you need to provide power to the element or not, so if it is required make sure the preamp/mixer you select has a phantom power option (most do).
  
  
  
  Here's a basic/generic setup:
• The microphone output is connected to the preamp input with a (balanced) XLR to XLR cable.
• The preamp output is connected to the mixer input with an XLR to XLR cable.
• The output of the mixer goes to the microphone input of the radio with an XLR to Foster plug. This is the point where you convert the balanced audio signal to unbalanced, and wire in your PTT switch.
• The audio + wire (pin 2 of XLR plug) is connected to the 'audio' pin of the Foster plug.
• The shield (pin 1 of XLR plug) and the audio - (pin 3 of XLR plug) get connected to the common (shield) pin of the Foster plug.
• Now, using a piece of single conductor shielded cable connect the shield to the common (shield) pin of the Foster plug and the center conductor to the 'ptt/transmit' pin of the Foster plug.
• Depending on the size of cable used you may/may not have to use a rat tail file (or dremel tool) to enlarge the opening in the Foster plug so your wires will fit through the strain relief.
• How you terminate the other end of the cable is up to you. You can solder a momentary N.O. switch directly to it, or put an inline jack on it so you can plug a hand or foot switch into it - lots of options here.
• If you want to add components to your setup simply add them to the daisy chain with another XLR cable.
• You can also use the TRS 1/4" (also a balanced signal) or the 1/4" mono (unbalanced) provisions if you want. You would follow the same procedure, but you wouldn't have a shield wire (pin 1 of XLR plug) terminating at the Foster plug.
• As far as what component goes where in the chain, I haven't seen any 'set in stone' order they should go in.
• If you use a seperate noise gate, I would put it inline last though.

I'm sure I forgot something along the way...if I did maybe someone will mention it...

Now, like anything interesting or fun to do that's a little technical, it doesn't sound like simple "plug-n-play". I'm going to save the above post to a draft for future reference. Looking around, there are many many types of mixing boards to choose from, and if someone was to go down this road, it looks like it might be worth doing some real reading and homework. Asking more experienced members, without fearing being ridiculed, would still be a very good idea for any member intersted in this subject, or really even any other.


I just briefly talked back and forth a couple of times with Sidewinder NJ on 27.025 a few minutes ago, and I wish I'd asked him (or could really) about what he's using. Afterall, he's one of the few REAL wideband AM audio 27mHZ stations out there, with literal "FM Broadcast quality" AM audio, truly. Do I think any of this is silly or a waste of time ? No, not at all.



Before making a few points or posing more questions on CB radio and Pro Audio, I'd like to make a few comments on why I myself, AND also MANY others, are interested in this field.

In some things and areas, some people like to experiment and try new things, or to do something different. Experimentation is in-part what the radio hobbies are all about. And it's also sometimes how new ideas or methods are introduced into the mainstream. To those who would view things in the light that things are "as good as it gets", should maybe stay content with enjoying the equipment they already own, along with the mentality and mindset that they already have. And that's fine. But there are people who enjoy doing something or owning & using something out-of-the-ordinary.


Another point that comes to mind is, perhaps some have stations consisting of multiple radios and multiple microphones. Others will find a good radio and a good mic, that works for them, and stick with them. On the other hand, maybe operators in this other multiple radio/mic category might need/want to adjust their audio chararteristics depending which radio/mic combination is being used at the moment. If a currently selected mic sounds good on my Hy-Gain 623 for instance, and I decide to suddenly change to a mic with a different sound, I might want to make adjustments to the sound quality using the mixer. Or instead I might want to use the same mic but switch between radios at intervals, for whatever reason I wish. Being able to alter the sound output beyond that of being stuck using only primitive "Mic Gain" or "SoundTracker" knobs, is a highly desireable capability to some. Someone interested in this sort of stationing would hope to see what others who are doing this type of thing have to say or recommend.



Why People Choose Better or "Alternative Quality" Products of any type

Similar examples in other areas:

• Cigars. They all "smoke" the same, but some would prefer to have one fine Cuban, versus a convenience store Black-and-Mild pack of 5.
• Wines or Beers. They all go down the same, but some would prefer say a good bottle or two of Corona or other quality beverage of choice, versus a whole 6-pack of Natural Light "Natties".
• Cars or Trucks. They ALL get you from point A to point B. But some would heavily invest in having a modified sports car or decked 4x4, rather than a simple commuter car. Know what I mean ?
• HiFi AM/FM/Audio/Video. A basic radio will pull in the music you want to hear, or TV the movies you want to see. Heck, go ahead and splurge and get one that's actual stereo. But for others, some might choose high-end HiFi radio equipment or elaborate HDTV Surround Sound Home Theatre systems. Some would view this level as needless, decadent or silly. And all the extra money spent as a waste. Still, for that extra top notch or two of quality, some would spend far more and think the results are still way worth it.
• Transmitting Radio Equipment. We can contact easily from even a basic decent radio. But some will like to utilize perhaps a full-function unit, or possibly even a fine old Tube rig such as a Tram or Browning. And speaking of older rigs, some would choose maybe even an older 23-channel radio. Not for everyone ? Certainly not. But for some they might have a preference in certain lower channels only anyway, such as 6 11 and 16. Once again, if someone is showing interest in something more, even with limited gains, let them ask questions and show interest.
  
  
  If it's "not for you", then sure, stick to what you have. And afterall----it is CB---so if you want voice your opinion , or if you really must then go ahead and "throw eggs" at others who might choose differently.

by KF3EG
I love it when people have more money than brains, 500 dollar Mic's IHY boxes, mixers, audio boards, computers.
What happened to communication audio? If one wants to sound like a FM broadcast station get a job as an anouncer in a broadcast station.
Buy the Mic that is made by the radio manufacture and set the audio up in the rig and use it. I forgot one would have to put their ego away and not keep up with Mr. Jones, sad.

CB Radio Wideband AM Audio

On the actual basics of improving transmitting sound quality (and it has been considered---read linked posts) the subject of bandwidth was brought up. It can and is done on both AM and SSB transmitting radios, no mystery there. There are station operators out there transmitting wideband AM, and some or utilizing ESSB extended single sideband. Some Amateur rigs may be better in this regard, or some would opt for real modification to an actual dedicated existing 11M rig.

And I've been wondering, and probably others too, is how is it exactly that certain CB transceivers have been modified to have increased audio bandwidth ? From the start, some radios have far better audio sections than others for a technician to work with in this regard, so I'm told. What exactly is done on a Cobra 29 or other radio, to achieve this result ?

Some are using Icoms etc on 11M or using something else better than a modified CB radio, that I know. Yet as many know also, not all Ham rigs have true AM, many are actually running at a reduced or surpressed carrier AM mode, not exactly the best for "true AM" afficianados.


Back To Using Pro Audio Sound ---or--- PC Soundcard Audio Processing

And here's another question I've been mulling over. From people interested in this whole subject, what about the use of a PC Soundcard Interface, versus the traditional physical external mixer ?


I bought both the Rig Blaster Plus and the Ultimate Linking Interface, and have also purchased the International Radio VOX BOX. Because I've seriously considered the possible use of the PC and a processing program, instead of external audio equipment. This will/could be handy for many reasons, aside from the increased audio adjustment capabilities and also the watergating and the like. It's definitely taking it in a somewhat similar, but different route, direction.


Although I am fairly well-practiced with PC's, I've never yet attempted to interface any radio & PC programs as of yet. There's the patching, cording, linking and all to be considered. Introducing a PC directly into the middle of the station---*especially at increased power levels*---can also make things a bit more tricky, and the installation needs to be bulletproof. This months' CQ Magazine has a nice article review on the RigBlaster Duo, which I found was quite good reading. I believe that the two units I have that I mentioned above, either of them will basically do the same job, and link me to a PC combined with using soundcard programs.


"If" that's a good route and alternative, I don't know. The article I quoted in the "Microphones: Vintage Studio Audio Broadcast Music Paging" thread mentions a very good point. Often, the voice sound found while engaging in popular internet chat rooms (such as Paltalk) sounds very good, actually. The mics are dynamic and provide good tonality, have depth and bass. All by being run through the PC. It was a good example mentioned and really wonder what other interested persons viewing this thread have found, and/or think ?



These two other threads linked below are certainly interconnected and contain some useful posts

Custom Built Digital Audio CB Base Station *NICE*
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Microphones: Vintage Studio Audio Broadcast Music Paging
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by W4MGY
Forget about all this BS concerning Heil mikes, and W2IHY processors and other expensive audio toys just to a SSB radio sound like an FM station. Save yer Shekels. I use a good old fashioned D-104 mike on a TUG-9 stand on everything I use...Ten Tec Omni V, Collins S/Line, and KWM-380. The D-104 has a 3.3 meg resistor in parallel to the crystal mike cartridge to flatten out the response. The output coupling capacitor of the preamp is 10x the stock value. That's it. Watch the setting of the preamp's level control. The amp is not to make the mike louder, it is used as a voltage amp to match impedences between the mike and radio. You don't need any processing with this either. Simpe, cheap, and effective; this setup doesn't pick up induced hum, doen't have the proximity effects of dynamic mics, and the audio cuts theough the pileup like a knife. BTW, this is a great mike for ragchewing too.

Below, let me quote an exerpt I was reading from a thread on Eham months ago. It was from along a similar topic line, improving audio. Now as usual, you had your "nay-sayers" and scrooge "bah humbug" types getting in there and either politely begging to differ or outright ridiculing the notion. I think some good came from the conversation, although done with the usual Ham slant. I think at times, some good can come from the different approach and willness found among some on the 11M band as well, and from a willingness "to try".


********************************************************************************************************************************************************************************************************************************************

RE: Thoughts on the Selection of a Microphone
by KA7RRB

Let's examine Heil for a moment. I happen to own and use a Goldline Pro, which is intended for studio recordings not amateur radio and I use it through a Mackie 1202VLZ Pro studio mixer which likewise is intended for studio production. I bought this equipment because I produce television programming. I also have some $900 wireless microphones and one that cost $1795.


I have used all of these various microphones in combination with the Heil foot switch and had nothing but compliments. There is some credit due to my being able to properly adjust an audio mixer and preamplifier. With the Mackie, this is done visually with the amplifier turned off. Once the proper level has been established then and only then is the unit connected to a radio.


Viewing the waveform on a scope or soliciting comments from listeners allows some fine adjustment of the preamp, and I use the equalizer section of the mixer to make my voice sound the way I want it to sound. I have found that a very minute amount of reverb ... the level of echo you might get from a warm room, adds a lot to the tonal quality and intelligibility of the audio.


What I'm after in a television production is to make the audio sound as though the performance is taking place in your living room. With modern home theater systems, the attention we pay to audio has increased very dramatically from the day when television had mediocre picture quality and terrible audio.


Question: Why would an amateur radio operator not want to sound as though he were sitting next to you in your shack if that were possible?


The answer is obvious and I'll tell you plainly that nobody's OEM microphone is going to get you there including Bob Heil's OEM versions that currently ship with some of the newer radios. The missing ingredient in amateur radio is the digital mixer and a man who knows how to operate it. The Heil microphone I use most of the time has 40 ~ 18Khz response, which exceeds SSB bandwidth on both ends, but the quality I can impress on the audio bandwidth that does come through is worth the expense and time.


I do not like the Heil Goldline Pro without the Mackie mixer. The bare microphone sounds no better than OEM bare microphones.


What I hope I have done here is introduce some audio conscious hams to the idea that simply paying for an expensive microphone is not going to produce the sound you're seeking. The missing ingredient is a high quality mixer with a very low noise floor. I recommend Mackie because I have worked with that brand for years. Others have their preference. I think Mackie wins the noise floor competition hands down. Some dislike the distinctive midrange shading and low end shading Mackie is known for, but more gold records and more Emmy Award television programs have been produced with Mackie boards than any other, so I rest my case.


If you want good sound then get a good mixer first. It will improve the quality of any microphone input passing through it and give you fine control over how you sound. Listen to yourself in the headphones. If it sounds good it is good. All that remains is to match the drive level to your transceiver preamp circuit and you have a winner.

[BREAK/REPLIES]


Speaking as an individual who expresses interest in speech recognition software, it sould be obvious to you why absolute accuracy is mandatory for that particular purpose.


I am a television producer. Part of my job is to insure that the audio is as pure and clean as the HDTV video feed we produce to go along with it.


Amateur radio has suffered long years of poor quality audio for many of the same reasons your home television suffered through 50 years of poor audio. The people who manufacture the equipment made a business decision that they could "get away" with selling a product that produced marginal audio quality and so they did. During the early years of single side band, it was not widely adopted because of the almost universal "Donald Duck" sound quality which grated on the ears of hams of the day who had grown up in the hobby listening to more or less high fidelity AM. SSB was quite a step backward.


There is no valid reason why anyone should be forced to endure poor audio quality from amateur radio transmissions. Reasonably priced equipment now exists to adjust the input level from a standard NAB XLR 600 ohm microphone so that it matches the input drive requirement of all modern transceivers. In the not too distant past it was fairly common to find high Z microphones in use on amateur radio transceivers. Today nearly every new radio is designed to accept 600 ohm balanced input microphones. As it happens, the output from modern digital mixers is also 600 ohms and so this delightful turn of events now removes the final excuse for bad audio.


The only missing ingredient is for amateur transceivers in the $2500+ price category to include an XLR input/output mixer with a 5 band EQ as an integral part of the radio, thus eliminating the need for an external mixer.


Americans have adopted the "half @ssed" approach to living. We make no attempt at quality any longer in this country, and that mind set is reflected in the fact that so many were so willing for so many years to accept audio quality not fit for a dog.


In my view, it is "good engineering practice" to insure that the stability and purity of your audio signal is as well managed as the RF portion of your signal. It requires very little additional effort to do it properly.


Good audio is a pleasure to hear. Bad audio requires needless labor and tires the listener quickly. Home theater systems have proven conclusively that if consumers are given a choice between good audio and bad audio they will choose good audio 100% of the time.


What makes you think that given the same choice in amateur radio anyone would knowingly and deliberately opt for poor audio quality when good audio quality is so simple to accomplish? Don't get on the air and talk about your audio, simply insure that the quality is up to broadcast standards and enjoy the compliments.

Hmmmm . . . I think he's on to something !




Is this all really silly or useless ? Not just for Amateur use but even for an 11M rig, stock or modified ? I don't think so. But what do others, who have something useful to contribute, or who are genuinely interested or have yet to comment think ?


I'd REALLY hope to see some others post here, who are genuinely interested in the topic of using: CB radio and Pro Audio gear, Wideband AM or Wideband Audio, PC Sound Cards and Interface devices, and other alternative methods for running extra-quality audio via their CB Citizens Band radio, or perhaps even an Amateur rig.


Foxhunter 351 NJ

[Hazelnut 7201]

Thank you Mr. Foxhunter, I admire what you are doing and the time and research you have put into this topic.

I have been trying different things all year to improve my audio, mostly quietly by myself because I have not seen anyone else that has my same goal in mind. I want a mobile that is easy to listen to, not interested in the “squash mud duck “thing or “Who’s got the loudest radio?”. Just something that is easy to listen to on any mobile with a junk speaker. I am not interested in going “wide band”, very few would get it anyway, but I would like to use all of the 300 to 3000 Hz that is available. The higher frequencies do a better job of getting through, but can be very annoying to listen to and most mobile speakers do a fantastic job of amplifying the annoyance factor of a mic/radio transmitting only in the top half of the frequency range.

I know that my goals are not as ambitious as yours and many others who are involved in improved audio/HiFi audio/Pro sound audio or what ever you want to call it. I am more interested in a Stock Class audio where as I am not modifying the radio, just the audio signal going into the radio. I would like to use the full audio spectrum available.

I have played around with a couple of equalizers and can get good response from them on the bench. But, when I take them mobile I can’t get rid of a ground loop “buz”.

I am interested in good technical information, please let me do my own time management study or economic assessment.

[3strucking]

thanks fox hunter for taking the time to post info that many of us are interested in. I want to have the best sounding audio that I can have in both my mobile and base station setups. There is a guy in Florida that goes by bass master that I hear often, and he has the best sounding station that I have heard so far. The quality of his audio sounds like you are listening to a fm station, as a matter of fact he sounds better than alot of them. Please continue posting on this subject as I would like all the info that I can get.

[Century21]

Good info Fox. Im also interested somewhat in it. Getting the am dj quality sound out of a cb with out spending 5000 dollars on the radio. Im going to be making the necessary mods to the cobra 2000 to achieve this soon. And I will end up using a foot switch to key the mic. Im going to run the regular mic cable out of the radio into a hobby box and the foot switch out of that down to the floor. and a 1/4 inch plug and any matching stuff i need to make to make sure everything matches up propperly. I have a little mic amp i built about 10 years ago for a couple bux if it needs more audio out of the mixer or what ever i use. I also already have boom mics and stuff. Just gotta do it as i have the time. And right now is not a good time hahah. I used to be the one with the over modulated radio bleeding on my microwave dinners, but for the past few years ive been trying to achieve understandable audio and still be at a good volume in the recieve radio. I have a sadelta cm-40 compression type mic. ( old mic ) . and i keep it half way bewteen 0 and 1 ( barely cracked ) it also has a tone adjustment on the bottom. IT seems to make the audio a little deeper sounding. But i want more! So im gonna start workin on it soon.
Im gonna take the output from a recieving radio, and record it on the pc as I change things.

[lucas]

Nice work, 10/10...kinda kicking my butt now for selling off all my pro audio gear, as i got out of deejaying/remixing/live sound .. BUT never the less here's a little some thing i have been working on. when i sold all my gear, i kept one part that i figured what the hell might come in handy later on, that was my sound blaster Audigy gold card. with super low legacy support. what does this mean in a nut shell. Lets see what i have done.

Items that i used.
one cobra 21LTD Classic
one Realistic cheap cb mic
one pyramid phase 3 REGULATED power supply
2 - 3.5 MM phone jack.
One spare or kick around the house 4 pin plug (for the radio)
one computer with one sound blaster audigy card (any card should work as long as you can hear your self through your computer speakers when talking into the mic)

The workings:

wire up the mic as you would for a 4 pin cobra setup MINUS the white wire. heres what i did, took the white wire coming off the mics element and solder on the 3.5 mm phone plug also i wiring the ground of the 3.5mm plug to the ground of the 4 pin going into the radio. Then took another 3.5mm plug and run that one from the line level output of my sound card and wired the left side + to the original mic element input on the radio and also wired the ground of the 3.5mm plug to well the ground. after finshing this, i went into my sound card options and selected "listen to this device" under the record tab, and microphone options. (this is only if your running windows 7 as im not sure about vista)(xp allows stereo mix listing). Made sure my levels where down on my computer, muted every thing else execpt the mic, went to my cb meters and set my modulation to where it should be and put it in REF mode. went back to the computer and started to raise the volume, watching that i DONT over modulate my radio. had a buddy down the road listen as i checked it out, all is good.

NOW the fun. because my sound card supports extremely low legacey when i talk in to my mic it has as no more then half a second delay. your probley woundering, if he's using a mic input on his sound card and line out on his sound card, it shouldn't have a delay. Wrong, because im using a plug in (software plug in that is) to allow me to use DSP (digital sound processor) on all my inputs of my sound card , what this means is i can use echo, reverb, flanger, phaser, EQS ect ect, or a noise toy (not that i rathar want to but can).


OH and forgot on real good one, makes on hell of a power mic to
I'v used this setup for a few weeks now and seem to work pretty good.
i hope this makes sense, it's one of those things that is kinda hard to explain in writing, something like this looks much better on drawing

[Lost Ram]

thanks fox hunter for taking the time to post info that many of us are interested in. I want to have the best sounding audio that I can have in both my mobile and base station setups. There is a guy in Florida that goes by bass master that I hear often, and he has the best sounding station that I have heard so far. The quality of his audio sounds like you are listening to a fm station, as a matter of fact he sounds better than alot of them. Please continue posting on this subject as I would like all the info that I can get.

Hello Sir, You are correct that Bass Master sounds SO GOOD!!!!!! I have talked to him several time but can not have a real conversation with all the skip going. If anyone is interested in buying a mic that sounds better the the D104 PM me for info'. I run mine in the low compression mode as everyone says that makes it the best. Everyone instantly Asked me what I did to my audio!!!!! Its sounds superb!!!!

[edited by 231 / PM sent]

[camogreen]

In case anyone is still interested or reading this thread check out [Please login or register to view this link] for almost all you need to know about good audio.

Mac

[420Snowman]

Bump, this is a good thread, old or not, I am looking to HiFi my station too


Snowman

[Red Warrior]

I have pro studio software and a professional mike that I have interfaced to both a Galaxy 95T and a Kenwood 570D.

I believe the biggest problem is the limited bandwidth of CB radio inhibits high fidelity audio. The receivers for CB radio are designed to be narrow banded and even if the transmitter puts a lot of audio on the air the receiver does not have the ability to reproduce it.

My 2 cents....

[Slim Pickins]

Thank You to everyone who posted here. I believe I have learned something that I could potentially use in the future here. Although, I will not claim to understand everything I have read here after the first reading.

73s
Paul

[Foxhunter]

Well likewise with AM/FM broadcast radios, received bandwidth is something that's stalled broadcast AM Hi-Def type stereo from becoming prevalent. It's just that so many AM/FM radios aren't built to hear AM as station engineers would like, because most existing radios aren't designed to be capable enough.


While admittedly the audio in the average CB is a little tight/restricted, nearly anyone can still immediately recognize and hear a station with super audio & bass. It might not be fully passed by the audio circuits, but we can still gladly hear someone who has crystal clear modulation, nice warmth and bass to their voice. Actually sounding life-like, instead of having the hissy scratchy audio of a 1930's phonograph like most CB's. So even with a stock CB, we can hear the difference how a real super audio station can sound, and it's big. Let me tell anyone this-----if I hear 20 stations all clamoring in DX land, and there's a single station who has awesome audio----they instantly stand out from the crowd and it's the station people want to talk to. Time and time again.


I think at this point there are a few routes someone can take in the general direction of having a focus on super audio. You can get several pieces of separate-component outboard "pro audio" type gear, and custom process the signal before going into the radio. Headway can be made going this route, but some of the audio is still lost by dumping the sound into bottleneck stock audio circuitry inside the CB.


One could also somewhat similarly go the W2IHY route and buy an EQ made for altering your miked sound. It can sound good, but something again is lost-in-translation within the CB circuitry.


Or an option is a buying one of the legendary tube boatanchor rigs so that you might have a wide TX and "tube sound".

Some would also try the setup some of the west coast guys are running with Motormouth's type product, but you're limited to base-only use and the Pro Tools program cost is expensive and radio-computer interface is clearly not for everyone.


Down in this neck of the woods, someone has been busy at work modifying nearly bypassing the radio audio circuits themselves and changing the way (and where) the radio modulates. It's the most life-like sound anyone can hear and the radio's that have been done this way sound "perfect". Purely natural tones with broadcast FM quality, gated quiet background in between words etc.


I personally think there's a lot of "smoke-screening" going on out there, and basically few will tell you fully and honestly how it's done. Many who get really really decent sounding stations do not want everyone else to sound just like them. In a nutshell, many of the truly best sounding stations heard out there, are using specially modified radios to get the stunning results that they do. All-the-while there are still others who try and accomplish it with multiple chains of add-on pro-audio gear or software etc (or any combination thereof). If you know the right person and have the money, you can have a beautiful realistic sounding radio and that's basically it. It can have other pro-audio goodies added on and inline for further processing, but it's mainly the radio needing building and modification.


Others will endlessly search and try all sorts of microphones and mike accessories or modifications etc etc on and on, and while coming closer to the goal, they'll unfortunately never actually fully achieve the desired results they're striving for.

[str8stroke]

good stuff to read. wish i had the time & money to get some of those "big station" sounds!

[nutcracker]

Excellant post, I will be hooking some rack gear up to a uniden washinton here this winter to see what its all about. I know the limited frequency range of the cb will definitely hold back the audio that could be produced, but it will make a difference. Even if the receiving station is on a stock cobra 29 the audio quality will still be there. I am running a stock receiver uniden 68, and even though it is not very widebanded, when a station running an old transmitter or rack gear it sounds beautiful.
All the audio gear can make you sound great, even better if the receiving station is equipped. But the best audio I have ever heard was from an old retired bc transmitter brought down to the ham bands, it is very hard to be the old heavy metal transmitters as far as quality goes.

[madsage]

Have any of you guys messed with any of the Virtual Studio stuff?

There is Virtual Studio called REAPER that is fully functional with a 5 second startup screen pitching you to buy.
But can be used indefinatly, also there are TONS of VST plugins available for it. So no need to spend money on studio rack equiptment, your radio wont beable to utilize most of its ability anyways. 'the way i see it, for what its worth'

That being said, compressors and noise gates and parabolic EQ's, AND your PC sound card are your friend.
Most **Censored** AC97 chips built onto your motherboard are capable 48100khz digital signal processors.
You can step up to ASIO supported cards and easily process at 91000khz if you like. However 48100khz is more than enough for even the widest bandwith for a CB radio.

Here is screen shot of my 1024x768 REAPER Virtual Studio. I'm using an old 12" LCD and micro PC with PentiumM/512m ram winXP and a SBLive card that fits in nicely with my radio gear.

BTW, tehre are 100's of free VST processor plugins on the net. Here is just a couple in this picture for example with reaper. While each track is meant for recording and mixing, You can plugin an effect to each track and passthrough from mic in to audio out. With a Larger LCD and desktop a guy can really get carried away. Dont over process your signal tho. Usualy a compressor and EQ is enough. There are tube effects and echo and reverb. The works. All free for you to download. and mess with. If anybody needs help, just ask.



933Arizona
in the stickers


[Please login or register to view this link]


The wave patern represented in the Visualizer Plugin in this screen shot, came from a Sing-Along Miley Cyrus Karaoke Toy my daughter broke and was headed to the garbage. =]
As you can see, You dont even need a fancy mic.

[DixieEcho82]

This is a good thread......keep it going. The guy on here that has the radios with the killer paint schemes has an EQ on his cobra 2000 i think. I have been wondering about this. I have an old JVC stereo EQ im not using anymore and will be following this. Speaking of good audio....has anyone ever heard "Bassmaster" out of florida ? Now that is good audio. This guy sounds better than a broadcast FM station everytime I hear him. Again guys GOOD THREAD!!

[madsage]

Lucas,

Obviously you were able to patch into the radio mic IN, right from audio card OUT?
Is this a straight wire job? Also is there another pre-amp from the power-mic? the impedance should not be correct. Was wondering how you over came this.

Thanks for the idea of using a stereo jack for IN/OUT/GRND. I just picked a switching one up at radio trash. should be able to wire it so 'out' passes to 'in' when the jack is unpluged.

933Arizona

[Night Crawler]

Obviously you were able to patch into the radio mic IN, right from audio card OUT?

If it's coming from the audio card the microphone amplifier stage in the radio should be bypassed and the output of the audio card should run directly to the modulator to get the best frequency response.