P25 audio quality

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fmalloy

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Ok after this post I am going to shut up about this until my 436HP arrives next Tuesday, but I've watched numerous YouTube videos of 436HP P25 audio recordings and they are absolutely awful! They all sound robotic and underwater, and the people talking sound like they shoved a huge wad of cotton in their mouths. Any interference causes choppy dropouts, whereas analog you got some hiss or static, but it was intelligible. On most of these recordings I can't even understand what the dispatchers/units are saying!

It sounds like computer text-to-speech from the 1990s. Stephen Hawking's speech synthesizer comes to mind.

Now, MP3 and other digital audio clearly sounds fantastic with the right compression level and sampling, so it's possible to have clear audio.

Sorry for venting, but P25 digital absolutely sucks. I don't know if it's the standard, the level of digital data compression, or what but it's awful. Not sure if it's Uniden decoding or signal processing or the standard, but if I was a LO I'd be pissed. Intelligible, clear audio dialog can mean the difference between life and death.
 

ofd8001

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A few years ago our fire department, along with all other governmental entities here in Louisville migrated fromt an analog conventional system to a trunked digital system.

There was a significant difference in the audio and it took getting used to the new sound. Without a doubt there is a difference in the two. And unless the system techs have done their fine tuning, sometimes background noises can lead to some funny sounds.

I think if you give it some time, you'll become accustomed to the different sound and won't give it a second thought.
 

stingray327

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Ok after this post I am going to shut up about this until my 436HP arrives next Tuesday, but I've watched numerous YouTube videos of 436HP P25 audio recordings and they are absolutely awful! They all sound robotic and underwater, and the people talking sound like they shoved a huge wad of cotton in their mouths. Any interference causes choppy dropouts, whereas analog you got some hiss or static, but it was intelligible. On most of these recordings I can't even understand what the dispatchers/units are saying!

It sounds like computer text-to-speech from the 1990s. Stephen Hawking's speech synthesizer comes to mind.

Now, MP3 and other digital audio clearly sounds fantastic with the right compression level and sampling, so it's possible to have clear audio.

Sorry for venting, but P25 digital absolutely sucks. I don't know if it's the standard, the level of digital data compression, or what but it's awful. Not sure if it's Uniden decoding or signal processing or the standard, but if I was a LO I'd be pissed. Intelligible, clear audio dialog can mean the difference between life and death.
My 436 sounds fine most of the time. Sometimes I hear signal break up. What I am really concerned about is that if this radio is picking up everything or is it missing or blind to some signals. I know certain channels have alot of traffic so it would seem those channels would always be on. I will even switch it down to one favorite list to see and it is still too quiet. I don't know I expected more traffic before the agency changed over that channel was always hopping. Now it seems dead but sometimes active.
 

budevans

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Ok after this post I am going to shut up about this until my 436HP arrives next Tuesday, but I've watched numerous YouTube videos of 436HP P25 audio recordings and they are absolutely awful! They all sound robotic and underwater, and the people talking sound like they shoved a huge wad of cotton in their mouths. Any interference causes choppy dropouts, whereas analog you got some hiss or static, but it was intelligible. On most of these recordings I can't even understand what the dispatchers/units are saying!

It sounds like computer text-to-speech from the 1990s. Stephen Hawking's speech synthesizer comes to mind.

Now, MP3 and other digital audio clearly sounds fantastic with the right compression level and sampling, so it's possible to have clear audio.

Sorry for venting, but P25 digital absolutely sucks. I don't know if it's the standard, the level of digital data compression, or what but it's awful. Not sure if it's Uniden decoding or signal processing or the standard, but if I was a LO I'd be pissed. Intelligible, clear audio dialog can mean the difference between life and death.
Not all P25 radio's sound the same. I have a GRE 500 and a Uniden 436. I monitor five P25 Simulcast systems plus several Moto Type II systems with P25 CAI.
Overall the GRE 500 sounds like conventional full quieting analog FM. Clear and very natural sounding voices. GRE just got P25 voice right.

So why did I buy a Uniden 436? One of the P25 Simulcast systems gives my 500 fits. One day it's crystal clear, the next garbled or no decode at all. So I took a chance and bought the 436 in early December. In the last month the 436 has handled that system with no issues.

Yes the 436's P25 audio is no match for the 500's, but the 436 can monitor that one system that the 500 can't. Plus it has capabilities that the 500 doesn't. So it's more future proof (a.k.a. Phase II capable) than the 500.

One other comment regarding the 436's audio. My local Fire Department has Harris P25 radio's, for mutual aid purposes. The P25 audio from the 436 is a virtual match for the P25 audio from the Harris radio's. So much for professional radio's sounding better.
 

fmalloy

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Thanks for the thoughtful replies.

I think capturing and decoding digital audio over radio susceptible to multipath and other issues must be very challenging. With analog, if there's interference, weak signal, etc. you get noisy audio, but you get audio. With digital, you drop too many bits you get...nothing.

As I say, I need to wait for the radio to arrive and see how it does with the P25 SVRCS here in the Bay Area. My 346XT received my local city's transmissions just fine.
 

SCPD

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Sorry for venting, but P25 digital absolutely sucks. I don't know if it's the standard, the level of digital data compression, or what but it's awful. Not sure if it's Uniden decoding or signal processing or the standard, but if I was a LO I'd be pissed. Intelligible, clear audio dialog can mean the difference between life and death.
It is not venting .. it is the truth. P25 does sound like **** that I have been able to tell. Personally .. we have an Edacs system and it is going away in a year being replaced with .. wait for it, a P25 system. I am going to miss the nice clean audio.

The only thing, you will probably get used to it, everyone else has.
 

Johnnydollar2

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P25 audio Quality

I've done a 180 on this subject. My old Pro96 did sound too much underwater* or like Donald Duck under water at times. Especially when the AGC was on. You get used to it after awhile. I was longing for the old Analog days too. But I've purchased a WS1080 and now like the P25 digital better. It's much more smooth and lifelike to my ears than the Pro96 duck sound. The TDMA talkgroups are LOUD and clear so much so you can hear the people breathing in the mic. I also have a lot of Analog traffic still in my area. Now after hearing the two compared with a much better digital voice decoder on the WS1080, I prefer digital to analog. Analog has too much drift and scratchiness to it, especially a frequency a county away, it's low and scratchy. I also wouldn't go by those Youtube videos too much as most of those are done with cheap Cameras with very inadequate mics the size of a button. I know the one's I did for my WS1080 didn't really do it justice as the sound is much better in person. I was pleasantly surprised by the WS1080 sound. A vote for Digital.
 

MrAntiDigital

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Welcome to digital.
Simply put, a plain and simple answer has been given here (quote above). Whether it is the background noise affecting it, the weather itself affecting it, it's garbled sound on a good day, or a firefighter or police officer who's message wasn't received when they needed it, it all adds up to the new and exciting world of Digital Radios.
 

ofd8001

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I've got about 40 years of fire service under my belt. At first there were only simplex channels in use. Then we went to an analog repeater system. Just a few years ago our community migrated to a P25 trunked digital system.

My opinion is that the new digital system is the best thing to happen for our public safety communications over those 40 years. Yes there have been distorted transmissions on the P25 system. But there were distorted transmissions on the simplex system and repeater system too - probably even more. I don't think there is a perfect voice communications medium out there - even face to face communications have to be repeated occasionally.

"What does P25 buy you?" P25 a technical solution to congestion in the frequency spectrum. This technology was to "tighten up" the band width of frequencies so that the spectrum could be divided a little more efficiently resulting in additional frequencies being available for use.

If you look at the cell phone industry, they initially started out as analog, but found that going to a digital standard proved to be more efficient. The same principle applies to public safety communications.
 

MrAntiDigital

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I've got about 40 years of fire service under my belt. At first there were only simplex channels in use. Then we went to an analog repeater system. Just a few years ago our community migrated to a P25 trunked digital system.

My opinion is that the new digital system is the best thing to happen for our public safety communications over those 40 years. Yes there have been distorted transmissions on the P25 system. But there were distorted transmissions on the simplex system and repeater system too - probably even more. I don't think there is a perfect voice communications medium out there - even face to face communications have to be repeated occasionally.

"What does P25 buy you?" P25 a technical solution to congestion in the frequency spectrum. This technology was to "tighten up" the band width of frequencies so that the spectrum could be divided a little more efficiently resulting in additional frequencies being available for use.

If you look at the cell phone industry, they initially started out as analog, but found that going to a digital standard proved to be more efficient. The same principle applies to public safety communications.
"OFD8001", interesting that you say that. I too have over 40 years of fire service under my belt, as both a volunteer firefighter, career firefighter, and a boss of a shift of career firefighters. As you state, I also have worked with analog and repeater systems. However our opinions are quite different regarding digital radio systems.

We may be considered Brothers as firefighters but when it comes to radios, I think we've both attended two different schools. You must remember the fads of Lime Green colored fire trucks because somebody said there was better visibility at night. Or how about the big push for "positive pressure ventilation". Those ideas also seemed to pass on with the latest fashions. After some of the reports regarding digital radios, we could be seeing a cooling trend in that too. According to some of the reports I'm getting here, some fire departments are now giving that second thoughts before making the move.

I recently read a thread on Nycfire.net in the radio section regarding digital radios. One post is from a FDNY Lt., another from a long time FDNY Supervising Dispatcher, and another is from a firefighter who was at the LODD of two firefighters and the permanent disability of another, partly to blame on the communications on the fireground using digital radios.

Of course I respect you for your time in the fire service. The heat and smoke is the same in your part of the country, as it is in mine. With that said, I think as a Brother Firefighter, you can understand exactly what I am talking about.
 

jonwienke

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My experience is that P25 digital is generally better quality audio than analog FM, especially narrowband analog FM. I listen to both on a daily basis.
 

SCPD

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My experience is that P25 digital is generally better quality audio than analog FM, especially narrowband analog FM. I listen to both on a daily basis.
I just want just once for someone that says P25 sounds so great to cough up some evidence of that. Upload a file .. but I think we all know that can be faked, so that is not even definitive proof.

From my experiences P25 sounds like crap compared to analog. I think it is cause they are just used to it .. but to someone that is new to it and has an open mind .. tells it as it is, it sucks.

I spoke to one of my friends a long time repeater technician .. his words much like my thoughts "any digital format is going to sound like **** compared to analog". I agree .. I have yet to see any proof otherwise.
 

jonwienke

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I listen to Washington County MD and Morgan County WV. Both are adjacent to the county where I reside. Morgan uses the WV-SIRN P25 system, and Washington uses VHF analog FM. Morgan is much clearer; less hiss, static, fades, dropouts, etc.

I can post files recorded by my 436HP, but it sounds like you'd persist in your opinions despite any evidence to the contrary.

I bought my scanner less than a year ago, so it's not a matter of being used to anything.

Should I believe you, or my lying ears???
 

kayn1n32008

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Morgan uses the WV-SIRN P25 system, and Washington uses VHF analog FM. Morgan is much clearer; less hiss, static, fades, dropouts, etc.
This is what I found with one of the companies I do work for. They went from conventional analogue to trunked DMR. While DMR is not P-25, I concur with listening to digital vs analogue. When a digital system is properly engineered, built to adequately cover the intended coverage area, and DSP/AGC is properly set up, the clean, uniform digital audio is much easier to listen to than hiss, static, and wildly varying audio levels of an analogue system.

Should I believe you, or my lying ears???

You have to remember, edmscan lives with in the engineered coverage of a 4 site, 800MHz simulcast, mixed mode EDACS wide system. edmscan IS correct, the EDACS system sounds VERY good on analogue, with in the engineered coverage area, I do listen to it as well. Heck I have been multiple kilometres away from any of the transmitters and I have been able to receive the system with out an antenna.

The other side of listening to P-25... Actual subscriber radios will always sound better than scanners.


Sent from my iPad using Tapatalk
 

SCPD

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Listen to my feed for a while for a direct comparison: Wauconda Police and Quad 3 Fire

800 MHz simulcast P25 on the left, VHF analog on the right.
Thanks .. I did listen and the right side is far better. I think those that prefer the P25 side are just used to it. There is nothing else to be said. And yes .. don't think my opinion will ever change until they actually do something to improve the audio quality.
 

ofd8001

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.. don't think my opinion will ever change until they actually do something to improve the audio quality.
The following is worth mentioning. Some scanners have trouble decoding simulcast digital systems, depending upon where the scanner is with respect to transmitters. When this happens, the audio sounds garbled or choppy.

Before I retired, I had a Uniden 996XT in my fire department vehicle, which was equipped with a mobile radio on our P25 system. In many places the audio was pristine on the mobile radio, but was horribly garbled on the scanner.

Scanners are made to be within purchasing reach of consumers. Public safety radios, given the importance, are made to get the job done with price being secondary. Thus public safety radios have "innards" that are much better at decoding simulcast systems.

So if you are judging the quality of P25 audio based on listening to a scanner, that may not be a fair test.
 
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