Why do digital scanners sound terrible

[car55]

Why do digital scanners sound terrible. I have used digital scanners and listen to many online police and fire who are on digital radio system it sounds terrible .

When I listen to analog systems I feel like I'm in heaven it so clear and much better natural voice.

Here is the complaints of digital radio system.

1.Voices sound harsh and muffled.
2.Voices sound very artificial ( lacks that natural voice)



Just listen to LAPD live LAPD - Citywide Dispatch and Hot Shots/Code 3 Live Scanner Audio Feed or Phoenix police live Maricopa County, Arizona (AZ) Live Police, Fire, and EMS Scanners on RadioReference.com you will see what I mean.



It obvious this does not happen to radio they use or they would never switch to digital.



Also prone to come in digitized.

Prone to chopping speech some times or systems that are simulcast ( because of timing decoding on more one tower site) Radio the department uses does not happen.

It big problem with Phoenix police and city Atlanta police and fire Fulton County, Georgia (GA) Live Police, Fire, and EMS Scanners on RadioReference.com

Well it is obvious this must be problem with scanners or the department would never switch to digital.


Not sure why this is the case or if it going get better in future for scanner users.

 

[loumaag]

Topic moved

This topic was moved to the general scanning forum. It is obviously about scanners and therefore does not belong in the Commercial and Professional radio section of the site.

 

[rak313]

Why do digital scanners sound terrible. ....

Well it is obvious this must be problem with scanners or the department would never switch to digital.


Not sure why this is the case or if it going get better in future for scanner users.

This thread http://forums.radioreference.com/ge...898-p25-simulcast-multipath-interference.html was devoted to this topic.

It will not answer your question - though.

Truth is - no one has a offered any definitive answers - although there are many theories. The consensus was scanners likely don't have I/Q decoders and have trouble decoding the modulation used in P25 (presumably resulting in higher bit error rates -but that was not the case in the live example links you provided). A second issue is the imbe decoder is patented. So it was suggested that maybe a software version of the imbe decoder was being used that was inferior.

These are both speculations - no one from Uniden or GRE responded.

Realize that P25 is only 9600 bps and of that - only 4400 bps are used for voice, and the imbe voice vocoder is old technology. Cell phones - who's voice quality is not all that great - (can) use much higher (14400bps) bit rate voice and has better performing vocoders.

This still doesn't address your question - that surely the subscriber radios aren't this bad or they would never have adopted by the police departments. There may be other political pressures at work here - e.g. Homeland Security money - that has strings requiring upgrade to P25.

I listened to the links you provided - and it sounded a bit tinny - but otherwise very copy-able. I have been listening to a software radio version of P25 decoder - and I would characterize it as less than what I would like to have for voice - but similar to analog. (but it is not a scanner)

 

[car55]

When you listen to analog system it like day and night the voice sound more natural and not harsh or muffled.

You have to move to small town or country has most cities have moved to digital now.

Here is older analog system in South Carolina 154.740, 154.025 and 154.400 listen to live feed here Lancaster County Sheriff's Office Live Scanner Audio Feed

You see what I mean .

Now listen to above feeds LAPD , Phoenix police , city of Atlanta police and fire.


You are saying the problem may be the scanners don't have I/Q decoders.

 

[wx5uif]

I used to think the digital sounding voice was just with scanners. However, my best friend is LEO and his agency just switched to digital. You can hear some of the digital artifact and muffled sounding in both his mobile radio and his hand held.

 

[Dude111]

Truth is - no one has a offered any definitive answers - although there are many theories.

I have the definate reason!

DIGITAL IS GARBAGE AND UNRELIABLE!!!!

Analogue has always been THE BEST as far as video/audio goes!

 

[AuntEnvy]

Funny you mention this

Although my area hasn't switched over yet, I have begun getting into the digital/trunked realm in surrounding counties. And yesterday afternoon I was checking out the abilities of the PSR800 and I said to myself, are you kidding me with this stuff?? How can this be "enjoyable"? I'd almost rather have static than the diginoise/scrambled voice nonsense.

I'm sure it's the scanner's deficiencies in "decoding" etc. They surely can't be experiencing this type of problem with their municipal radios.

If this is the future then I guess it's going to be a gloomy one.

 

[bfperez]

I think it's the codec/vocoder and the limited bandwidth available. The receiver and how it decodes also plays a part.

Short version-I hate the sound of P25/Astro IMBE. I haven't heard P25 Phase II, so I don't know how that sounds.

I sarcastically refer to digital voice, esp. P25 and Astro IMBE as 'soulless' because I have a lot of trouble discerning the person talking.

On the analog systems, I've gotten to the point where in some cases I know which PD's TG I'm on due to the tone of voice and inflections, something I've never been able to really pick up from Nellis AFB P25, SNACC Astro IMBE, etc. and was kind of able to with LV Metro's OpenSky patches to VHF.

Everyone sounds the same, and at least in the P25 world the 'rendering' of background noise is the most unnatural, bizarre collection of tones I've ever heard.

It's also worth pointing out that some real background noise seems to be necessary to really understand what's being said-it seems to form a sort of baseline that's missing when a digital conversation is either silence or an almost disembodied voice

 

[mikewazowski]

I sarcastically refer to digital voice, esp. P25 and Astro IMBE as 'soulless' because I have a lot of trouble discerning the person talking.

Just for reference, there's no difference between P25 and Astro IMBE. They're one and the same.

 

[rak313]

...You are saying the problem may be the scanners don't have I/Q decoders.

This was the conclusion of those responding to the thread - but no proof that the scanners don't have I/Q decoding.

But that does not address what you are complaining about - that digital P25 does not sound as good as analog. It was addressing the inability of the consumer digital scanners to receive the P25 simulcast systems without garbled R2D2 like sounds, pops, chirps, etc., presumably due to high bit error rates.

For what its worth - i listened to the radio ref feed for my county Onondaga County, New York (NY) Live Police, Fire, and EMS Scanners on RadioReference.com - while simultaneously listening to it on my software defined radio P25 receive (about a 2-3 sec time difference), and I noticed on several occasions - the radio ref feed would pick up mid sentence - missing 1-2 seconds of what was said. Also - the radio ref feed has a lot more treble.

 

[AuntEnvy]

I can relate

I think it's the codec/vocoder and the limited bandwidth available. The receiver and how it decodes also plays a part.

Short version-I hate the sound of P25/Astro IMBE. I haven't heard P25 Phase II, so I don't know how that sounds.

I sarcastically refer to digital voice, esp. P25 and Astro IMBE as 'soulless' because I have a lot of trouble discerning the person talking.

On the analog systems, I've gotten to the point where in some cases I know which PD's TG I'm on due to the tone of voice and inflections, something I've never been able to really pick up from Nellis AFB P25, SNACC Astro IMBE, etc. and was kind of able to with LV Metro's OpenSky patches to VHF.

Everyone sounds the same, and at least in the P25 world the 'rendering' of background noise is the most unnatural, bizarre collection of tones I've ever heard.

It's also worth pointing out that some real background noise seems to be necessary to really understand what's being said-it seems to form a sort of baseline that's missing when a digital conversation is either silence or an almost disembodied voice

I definitely understand what you mean by this perez. It's somewhat distressing.

It's akin to what I wrote a while back about the "automated dispatch" system that Indianapolis is using. It's almost unlistenable and a little bit creepy.

Seems to me it would sacrifice crucial response time, not to mention completely unnecessary. What is the point of taking a call, then "feeding it"(?) to a computer system so it can do what the dispatcher would be doing...??

It's all getting way too complicated- for no reason!

 

[AZScanner]

Digital radio is like the little girl with the curl. When she was good, she was very good, and when she was bad she was TERRIBLE.

Each part of a digital transmission is basically an all or nothing proposition, and a $500 digital scanner is simply NOT going to have the same robust error correction and dedicated hardware that a $5000 professional radio is going to have. It just can't. There are times when my old BC796 sounds so clean and clear on our DTRS and then there are other times when you can't understand jack ***** coming out of the speaker. That's not to say that digital public safety radio isn't reliable. It is actually in some cases more reliable than analog, as the Phoenix Fire department discovered during extensive testing.

Like it or not it's here to stay. Let's just be thankful you can monitor it on a $20 RTL dongle instead of strictly being the domain of $500 scanners that sound awful half the time.

-AZ

 

[W8RMH]

Seems to me it would sacrifice crucial response time, not to mention completely unnecessary. What is the point of taking a call, then "feeding it"(?) to a computer system so it can do what the dispatcher would be doing...??

The automated system can dispatch up to 20 calls simultaneously. A dispatcher can only dispatch one call at a time.

If they have 4 calls it may take up to 4 minutes just to dispatch the calls.

The automated system would dispatch all four at the same time.

Benefits of Automated Dispatching

By separating the act of speaking the dispatch from the dispatcher, and through a variety of fire station alerting technologies, Locution Systems’ CADVoice® fire station alerting system offers the following benefits:

* Faster response times
* Ability to handle higher call volumes without adding staff
* Reduced call stacking
* Reduced stress for 911 dispatchers and first responders
* Reduced employee turnover at the communications center due to reduced dispatcher stress

 

[KD2EE]

Each part of a digital transmission is basically an all or nothing proposition, and a $500 digital scanner is simply NOT going to have the same robust error correction and dedicated hardware that a $5000 professional radio is going to have. It just can't.

That's the thing, though, right? Either the scanner got enough of the packet to decode it, or it didn't. Based on the fact that we're hearing audio, I have to assume that there may be a large bit error rate, but the packet is being received within the limitations of the decoder, and the decoder is decoding what it was meant to. The one plausible thing that someone said is that the decoder may be incomplete because the true decoder is patented, but I think the main issue just has to be that there isn't enough data there in the first place. Remember that field units rarely have any understanding of the underlying technology. I've seen cops with radios with broken antennas or wrong antennas, and all sorts of people using HTs from inside their cars/ambulances. When you're in those conditions, analog sounds terrible too.

 

[ofd8001]

As a public safety responder, I love our digital system, which is a simulcast system. To me the voice is much more clear than our analog system was. I would not want to revert to analog. Yeah there are some of my colleagues elsewhere who may have experienced problems, but I'm just not seeing them happen with our system.

(The only weird thing is the milli-second delay as the voice is being digitized. I can stand next to someone who is transmitting as in counting from 1 to 5. When he gets to "five", my radio is hearing the "one".)

As a scanner listener, I hate our simulcast digital system. That's because of the garble occuring when my scanner is receving multiple sites and has a nervous breakdown trying to make sense of what it is hearing.

But as noted above, that's the difference between a real costly portable radio and a semi costly scanner. Just because a system may sound poorly on a scanner, that doesn't mean the actual users of a system are hearing things just as poorly.

 

[AuntEnvy]

I suppose some of that makes sense

The automated system can dispatch up to 20 calls simultaneously. A dispatcher can only dispatch one call at a time.

If they have 4 calls it may take up to 4 minutes just to dispatch the calls.

The automated system would dispatch all four at the same time.

Benefits of Automated Dispatching

By separating the act of speaking the dispatch from the dispatcher, and through a variety of fire station alerting technologies, Locution Systems’ CADVoice® fire station alerting system offers the following benefits:

* Faster response times
* Ability to handle higher call volumes without adding staff
* Reduced call stacking
* Reduced stress for 911 dispatchers and first responders
* Reduced employee turnover at the communications center due to reduced dispatcher stress

But I still don't see that it saves that much time or "reduces stress" without the computer actually answering the call.

It sounds more like a sales pitch, basically unproven, using society's "poor me" excuses and lawsuit-happy/workmen's comp/insurance scare tactics.

If certain people can't handle stress, those aren't the jobs for them, plain and simple. No different than any other employs.

 

[AuntEnvy]

Ahh, but alas...

Like it or not it's here to stay. Let's just be thankful you can monitor it on a $20 RTL dongle instead of strictly being the domain of $500 scanners that sound awful half the time.


The $20 RTL dongle...

 

[car55]

Digital radio is like the little girl with the curl. When she was good, she was very good, and when she was bad she was TERRIBLE.

Each part of a digital transmission is basically an all or nothing proposition, and a $500 digital scanner is simply NOT going to have the same robust error correction and dedicated hardware that a $5000 professional radio is going to have. It just can't. There are times when my old BC796 sounds so clean and clear on our DTRS and then there are other times when you can't understand jack ***** coming out of the speaker. That's not to say that digital public safety radio isn't reliable. It is actually in some cases more reliable than analog, as the Phoenix Fire department discovered during extensive testing.

Like it or not it's here to stay. Let's just be thankful you can monitor it on a $20 RTL dongle instead of strictly being the domain of $500 scanners that sound awful half the time.

-AZ

That is just one problem scanner users have because if there are errors it comes in digitized.

But problem I was getting at is voice sound harsh , muffled and very artificial ( lacks that natural voice) this has nothing do with errors but seem the way the scanner understands the digital stream than converting it back to analog.

I have new smart phone and it does not sound any thing like my scanner NOT harsh , muffled or artificial voice . In the past digital cell phones where terrible.

No public safety would go to digital radio system if voice sounded worse than analog .

These seems be problem with scanners the way they understands the digital stream than converting it back to analog.

 

[pepsima1]

Well you can't even buy a cheap scanner really anymore. All of the stock of cheap scanners are dwindlwing because there are no new companies making any of the scanner lines right now. Uniden is still making the bcd396xt/996xt but they are pretty much junk anyways but thats pretty much all we got right now. Digital has been pretty crappy but they say that there are some newer firmwares out there right now, but some still have troubles. GRE is out of business for the time being. All of their models are selling for high prices on ebay and amazon and they are not worth the hijacked prices.

Just move over to the commerical side and buy a nice Motorola handheld and program it yourself and learn. But you might pay double or triple for a nice radio and you have to spend the time researching and figuring out on how to program them. Worth the time I do say so. They sound so awesome and thats the way a radio should sound. Just my 1 cent of opinion.

 

[car55]

As a scanner listener, I hate our simulcast digital system. That's because of the garble occuring when my scanner is receving multiple sites and has a nervous breakdown trying to make sense of what it is hearing.

But as noted above, that's the difference between a real costly portable radio and a semi costly scanner. Just because a system may sound poorly on a scanner, that doesn't mean the actual users of a system are hearing things just as poorly.

It not so much some of these are coming in garble in case of LAPD - Citywide Dispatch and Hot Shots/Code 3 Live Scanner Audio Feed But it sounds muffled and very artificial voice.

When you listen to Lancaster County Sheriff's Office Live Scanner Audio Feed the voice sounds more natural .

That what I was trying to explain.