Scanners vs. Professional Radios on P25 Audio Quality

[jlanfn]

Note: This thread is not about comparing analog and digital audio quality nor is it about your personal level of satisfaction with your scanner's digital audio quality. We already have plenty of discussion in those areas in the RR forums.

Now, on with my questions...

It seems that I have always heard/read that it is a known fact that all of the current and past digital scanners have vastly inferior P25 audio quality than professional P25 radios' audio quality.

1. How true is this?

2. Can anyone explain/summarize why this is true? I'm looking for technical differences between scanners and professional radios--shortcomings in scanners that cause poor P25 audio quality.

3. Why don't scanner manufacturers focus on making scanners with P25 audio quality that is at least on par with professional radios? Are they afraid of making scanners that are too large or too expensive?

-Thanks

 

[N9JIG]

We have a system radio on our statewide P25 digital system, and we are in a simulcast area of that system. The radio has crystal clear audio, and when we first got it it was kind of discomforting for me as I couldn't place where the voices were coming from since they didn't sound like they were coming from a radio.

Right next to it we have a BC996T scanner that monitors different talkgroups on the same system, while most of the time it works fine, it does choke occasionally due to the simulcast situation.

I think you hit it on the head, digital scanners are usually right about $500 since a good chunk of change has to go to the vocoder rights, a more robust one would make the scanner too expensive for most.

A scanner unfortunately has to be all things to all people, another word for this is compromise. Smaller speakers, less robust audio circuits and wide front ends tend to make scanners worse than professional radios which are geared toward a much smaller range of target frequencies. Scanners are often more sensitive than two-ways but less selective. The audio processing is worse, but often the scanner is a tenth the cost.

 

[af5rn]

The radio has crystal clear audio, and when we first got it it was kind of discomforting for me as I couldn't place where the voices were coming from since they didn't sound like they were coming from a radio.

LOL! That is such a good description of it! It took me a very long time to get used to the P25 system we used in the military. Everytime your radio started talking, you'd look around trying to figure out what you were hearing. By the time you figured it out, you had missed what had been said. It's almost like having to translate a foreign language in your head before understanding it. It's a very unnatural thing.

Audio quality is indeed better on professional equipment than on a scanner, but it still sucks. I am not a fan at all. I suspect P25 is a passing phase that will be obsolete in the near future as something better replaces it.

 

[n1das]

Note: This thread is not about comparing analog and digital audio quality nor is it about your personal level of satisfaction with your scanner's digital audio quality. We already have plenty of discussion in those areas in the RR forums.

Now, on with my questions...

It seems that I have always heard/read that it is a known fact that all of the current and past digital scanners have vastly inferior P25 audio quality than professional P25 radios' audio quality.

1. How true is this?

2. Can anyone explain/summarize why this is true? I'm looking for technical differences between scanners and professional radios--shortcomings in scanners that cause poor P25 audio quality.

3. Why don't scanner manufacturers focus on making scanners with P25 audio quality that is at least on par with professional radios? Are they afraid of making scanners that are too large or too expensive?

-Thanks

1. It is generally true, but as usual YMMV. I like my RadioShack Pro-96 (mfg'd by GRE) P25 audio much better than my Uniden BCD396T audio. I also have an early BC250D Uniden handheld, the first P25-capable scanner to hit the streets. I've previously owned two Icom IC-F70DT portables and the P25 receive audio quality was inferior to my RS Pro-96 audio although the F70DT portable cranked up a lot louder. OTOH, the P25 receive audio quality in my Kenwood TK-5210K3 P25 handheld blows away any scanner I own. Bottom line is YMMV.

2. Why the differences? It has to do with how the P25 decoding is implemented. In the early Uniden scanner models that require the P25 digital board option to be installed, the digital board does the decoding using the raw FM discriminator output. In the RadioShack Pro-96 handheld, the last IF stage goes straight into the DSP chip that does the decoding. The FM discriminator that normally recovers analog audio for analog reception is never involved because the DSP chip uses the IF signal directly. GRE is doing the decoding in the frequency domain while the digital option board in the early Unidens does the decoding in the time domain. Either way will work in theory. GRE does it the way Motorola supposedly does it in their P25 gear.

3. My complaints with receive audio from handheld scanners is that even though the audio quality is good, there is never enough audio output to be able to hear the radio noisy environments. I want receive audio from a handheld scanner to have some punch to it like the good commercial radios have. As far as the P25 audio quality goes in a scanner, it's close to what comes out of a real P25 radio. A lot of the differences have to do with the specs the radios were designed to. Scanners generally are consumer grade products while real P25 professional radios are commercial or professional grade. The real P25 professional radios are the best radios money can buy. One issue with scanners is cost and the other issue is demand for professional sounding audio in the scanner market isn't strong enough (yet).

 

[trace1]

I've had my Motorola XTS 3000 and BCD396T side-by-side and they actually sound rather comparable to each other.