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CB RADIO MICROPHONE AUDIO PERFORMANCE
- Thread starter TonyV225
- Start date
Now thats funny...
Actually it's not.
When I see threads on CW, digital modes etc, I just pass them by because I'm indifferent to those operations and I don't try to belittle those who are interested.
When the subject of wide audio comes up, people who admittedly have no interest in either AM or eSSB, still feel the need to chime in and diminish the whole idea.
So I think it's jealousy, but what do you call it? Something compels them to make negative remarks on issues that they aren't interested in and which doesn't effect them.
Hi-Fi and communications grade audio each have their place. I'll use the rack 90% of the time and as soon as I hit a pileup I grab the D-104 on the fly. What sounds the most pleasant to the ear in respect to Hi-Fi is usually the absolute worse frequency response for being copied through noise. Surprisingly I find it would take about a 10 db increase in signal to bring the Hi-Fi audio up to the same level of copy through noise as the simple D-104 does on AM.
Another issue with Hi-Fi is people tend to underestimate the amount of EQing it actually takes to make things sound right through the typical receiver. Much distortion is caused in the lower frequencies due to improper EQ settings. In fact, most EQ units do not even have enough range to clean up the 250 to 300 cycle range. That's right where most receivers start to roll off. When you try to boost the low end below this point, it's the range that distorts the fastest.
That makes everything sound muffled and nearly every word seems to contain bass that is exaggerated. With mics that have good bass response, it's not uncommon to have to cut the 250 to 300 cycle band by as much as 20 to 30 db before you can boost anything below 100 cycles by 10 db. If you can do this, then when you say words that contain lots of bass, it can sound thunderous through a receiver with a good speaker and decent response. It's also just as clean as the best AM broadcast signals without any distortion or breath pops.
That will take care of the low end which incidentally does not consume more spectrum bandwidth like extending the treble can quickly do. This is where many operators run into being bad neighbors on the band. You can get that full sound without needing to consume 4 times the bandwidth of a normal signal. Just bringing the treble up to around 5 KHz. makes a huge improvement in fidelity without taking out a ton of spectrum.
Extend the bass about 3 times lower but only extend the treble about 50% higher. The treble requires very sharp filtering to remove everything above the desired cutoff frequency. Simple filters may only attenuate a few db at the cutoff frequency when we want brick wall filtering at 20 db or more and a very sharp cutoff. These requirements are well beyond the range of most analog EQ units on both the high and low end of the spectrum.
That's not to say a typical EQ with a 12 to 15 db range and wide bandpass skirts won't make big improvements. It just means you may have to realize the limitations of the equipment and cut the frequency response to a practical point in order to remove distortion in the low end and unnecessary consumption of spectrum. If you can only make a 12 db cut at 250 cycles, you probably won't be able to boost anything below that point and will be lucky to keep it flat before distortion sets in.
Another issue with Hi-Fi is people tend to underestimate the amount of EQing it actually takes to make things sound right through the typical receiver. Much distortion is caused in the lower frequencies due to improper EQ settings. In fact, most EQ units do not even have enough range to clean up the 250 to 300 cycle range. That's right where most receivers start to roll off. When you try to boost the low end below this point, it's the range that distorts the fastest.
That makes everything sound muffled and nearly every word seems to contain bass that is exaggerated. With mics that have good bass response, it's not uncommon to have to cut the 250 to 300 cycle band by as much as 20 to 30 db before you can boost anything below 100 cycles by 10 db. If you can do this, then when you say words that contain lots of bass, it can sound thunderous through a receiver with a good speaker and decent response. It's also just as clean as the best AM broadcast signals without any distortion or breath pops.
That will take care of the low end which incidentally does not consume more spectrum bandwidth like extending the treble can quickly do. This is where many operators run into being bad neighbors on the band. You can get that full sound without needing to consume 4 times the bandwidth of a normal signal. Just bringing the treble up to around 5 KHz. makes a huge improvement in fidelity without taking out a ton of spectrum.
Extend the bass about 3 times lower but only extend the treble about 50% higher. The treble requires very sharp filtering to remove everything above the desired cutoff frequency. Simple filters may only attenuate a few db at the cutoff frequency when we want brick wall filtering at 20 db or more and a very sharp cutoff. These requirements are well beyond the range of most analog EQ units on both the high and low end of the spectrum.
That's not to say a typical EQ with a 12 to 15 db range and wide bandpass skirts won't make big improvements. It just means you may have to realize the limitations of the equipment and cut the frequency response to a practical point in order to remove distortion in the low end and unnecessary consumption of spectrum. If you can only make a 12 db cut at 250 cycles, you probably won't be able to boost anything below that point and will be lucky to keep it flat before distortion sets in.
Because when engaged in a QSO and someone with 15-20 KHz bandwidth parks his ass 5 KHz away and starts jabbering away he QRM's the on-going QSO and most often has the attitude that you should get a radio with better filters when in fact he would be inside the passband of a 500Hz CW filter at that point.
Please see above reason this is not true. It is far from jealousy.
You are right. It is a problem fueled by a bad attitude however the bad attitude is with the wide operator that parks close to an on-going QSO and does not give a damn about QRMing it. Heard it many times and experienced it many times as well. Remember something, I AM one of the operators that likes to have a wider than normal audio bandwidth but on AM mainly but I do not encroach on other stations because I know how wide my station is and I DO give a damn about QRMing someone. As for the laziness aspect, I fail to even comprehend that one. There is no effort in buying a piece of equipment and plugging it in. That is about all that is required to enhance most radios. W2IHY has everything you need for virtually plug and play. No effort (or knowledge) required.
Perfectly said, CK.
I have made some enhancements to my CB radio to open up the TX bandwidth so I can sound fuller with my audio. But I'll never run anything really wide-banded for the reason CK mentioned... I am respectful of other people's conversations and I don't want to run something that could possibly interfere.
Besides, when it's all said and done, it's a CB radio. In today's world of DSP and selectable filters, you can buy an HF rig that could do much better than a CB radio anyhow. It's like trying to make a Cadillac out of a Yugo. I understand doing some simple mods, like maybe changing out a couple of cap values in the mic audio circuit and using a studio mic, but all of the audio processing and EQ's is a little over the top for me, especially on a CB radio in the CB and the freeband. I love how MMM sounds, but I can't be within 2 channels of him, he wipes out my receive and I have a double conversion RX chassis CB with a Channel Guard filter installed.
Ultimately, if people want to do that sort of thing, it is their right and their radio. And I get that. But in light of that you have to be more aware of the band and what's going on around you a few channels up or down. Sadly, some people just don't care.
~Cheers~
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Let's be honest. 90% of radios sound pretty shitty. Overdriven flat topping carrier pinching muddafukkas.
So your 10k plus and 10k minus. Is anyone else really using channels 5 or 7? If they are they must live pretty close ir full of shit. Same can be said about channels 27 and 29.
Now on 80 maybe it should be a little narrower..but not much. That ssb will just move closer. Perhaps it's showing off at a 20k audio, but am can an should sound good. And 11m is the ONLY place you can do it.
359 nailed it. The fact you can't order a hifi rig from AES is reason enough for me. You always can sound better. Why waste your money on the latest rice box if you can make your yard sale cobra sound better. I love the fact I hear more and more good sounding stations. Guess it's easier to bitch then pickup an iron.
So your 10k plus and 10k minus. Is anyone else really using channels 5 or 7? If they are they must live pretty close ir full of shit. Same can be said about channels 27 and 29.
Now on 80 maybe it should be a little narrower..but not much. That ssb will just move closer. Perhaps it's showing off at a 20k audio, but am can an should sound good. And 11m is the ONLY place you can do it.
359 nailed it. The fact you can't order a hifi rig from AES is reason enough for me. You always can sound better. Why waste your money on the latest rice box if you can make your yard sale cobra sound better. I love the fact I hear more and more good sounding stations. Guess it's easier to bitch then pickup an iron.
I can tell you why 90% of the CB's out there sound bad. It's because most CB'ers are either uneducated, or ignorant. The average CB'er wants LOUD. Most don't care about audio quality, they simply want to be LOUD. Hence the pinched off, clipped, nasty nasally sounding stuff out there.
I can totally appreciate a good sounding station on AM or SSB. But 10k on either side? That's like trying to turn AM into FM!
Here's the other side.... you cannot truly appreciate that kind of hi-fi audio until you get a radio that can receive it properly. The average CB radio does not have the proper filters to "accept" and process the transmit of widebanded hi-fi radios. The filters on a CB have narrow bandwidths for a reason. This is especially true in the newer radios. MMM sounds AMAZING on my Tram D201, but on my Madison he sounds nothing like he does on the Tram. Why? The older radios didn't employ the filtering that the new radios have now.
Moral of the story? A properly tuned/aligned radio with a couple small mods to to open up TX bandwidth and a good microphone will sound damn near as good as someone pounding out 20khz of bandwidth. Because unless everyone goes out and mods the RX in their radios to accommodate all that bandwidth, it's really not going to sound much different.
~Cheers~
I can totally appreciate a good sounding station on AM or SSB. But 10k on either side? That's like trying to turn AM into FM!
Here's the other side.... you cannot truly appreciate that kind of hi-fi audio until you get a radio that can receive it properly. The average CB radio does not have the proper filters to "accept" and process the transmit of widebanded hi-fi radios. The filters on a CB have narrow bandwidths for a reason. This is especially true in the newer radios. MMM sounds AMAZING on my Tram D201, but on my Madison he sounds nothing like he does on the Tram. Why? The older radios didn't employ the filtering that the new radios have now.
Moral of the story? A properly tuned/aligned radio with a couple small mods to to open up TX bandwidth and a good microphone will sound damn near as good as someone pounding out 20khz of bandwidth. Because unless everyone goes out and mods the RX in their radios to accommodate all that bandwidth, it's really not going to sound much different.
~Cheers~
Exit is spot on we have tro take into consideration of the radios filtering, If a radio wasnt filtered you would be getting hammered from all adjacent channels and you would be ripping your hair out or tossing your radio out the window in frustration from the jumbled garbled mess you would be hearing. I guess as they say very seldome can you have your cake and eat it to we have to take the bad with the good and and often have to sacrifice one thing for the other.
So you deliberately operate in a manner that massively reduces the distance you can talk (the wider the bandwidth the less distance per watt your signal will go) and that very very few people can get the full benefit of? Mad.
"But you sound like a broadcast station" said nobody ever at the other end listening on their CB through the crappy internal speaker they come with.
I got a Flex 6500 recently. Its quite interesting listening to ESSB. It sounds utterly shite until you open the RX bandwidth right out. What is also interesting is looking at the waterfall and seeing just how many other signals it stomps over because it isn't just the 10-20kHz of bandwidth you intentionally use, its double that or if you're overdriving, even more because your transmitted signal doesn't have a vertical wall to it, rather it tapers off gradually.