TRX-2 speaker jack low audio output

[Anderegg]

Yikes...I heard P2 on the TRX series have adequate volume while Phase 1 and analog are low, is this accurate? My transition to TRX2's will come only when my county transitions to P2.

I run a Whistler WS1098 into my PC, and REQUIRE a ground loop isolator ($10) for it to work properly. The WS1098 speaker jack output at 15 matches the level of my old PRO197's with their volume knob white notches pointed straight up, mid volume I believe?

Paul

 

[Ubbe]

There are at least no difference in volume between Digital DMR and analog in a TRX-2.

/Ubbe

 

[SOFA_KING]

The TRX-2 External Speaker jack on the back of the scanner (not the front headphone jack) is a straight connection to the audio amplifier. No additional resistors are added to the circuit. When you plug in a MONO (two conductor) jack, the internal speaker is disconnected. This is as simple as it gets. Headphone jacks are usually STEREO and have resistors to match headphones, as well as protect against damaging your hearing if you accidentally have the volume turned up high.

The audio amplifier specification on the TRX-2 is only 500mW (half Watt) at 8 Ohms, and may not drive external speakers rated for high wattage hard enough to move enough "air", which is what speakers do. The internal speaker is rated at 8 Ohms, and can handle up to 1.5 Watts (three times the amplifier output). This is just overhead, and has nothing to do with any "extra" volume although, a 1.5 Watt rated speaker would probably move more air than a 15 Watt rated speaker. High wattage speakers want to be driven harder.

Speaker "efficiency" has everything to do with actual "volume". In the days when specifications were important enough to be printed, we would look for the highest SPL (sound pressure level) dB output at rated impedance (8 Ohms in this case) with 1 Watt as the reference amplifier output. The greater the dB level, the louder the speaker. Not all speakers are the same. Some deliver, and some don't. And playing games with 2 or 4 Ohm speakers to obtain higher volume only jeopardizes blowing out the scanner audio amplifier (not a good idea).

Given the low output of the TRX-2 amplifier, looking for a "good sounding" speaker with the highest SPL dB output is the answer to getting sufficient volume. Using the excellent AGC feature (especially on digital signals) will smooth out the vast variances in system/operator misuse. That is one great thing Whistler has over Uniden (AGC that actually works...and works very well). As far as Audio Boost, I use it for primary channels that I want to be a "cut above" the other channels. It works well for that.

Stick with 8 Ohm external speakers, and try lower wattage ratings to (hopefully) produce more efficiency in output volume. If you can compare dB ratings for 1 Watt SPL, go with the highest dB number you can. That is what you need to get the volume.

Phil

 

[bjizzle]

There are at least no difference in volume between Digital DMR and analog in a TRX-2.

/Ubbe

I think it's the modulation on their end. I only pick up one dmr signal and it is rare that it comes through all P25 and NXDN in these parts.

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[Ubbe]

I haven't looked inside the TRX-2 but since 20 years back the IC small power loudspeaker amplifiers have internal protection for overheat, excessive current and shortcircuits.

Don't know what Whistler uses but I have worked for Motorola for more than 30 years and never encountered or heard in the shop of an blown amplifier due to using the wrong speaker or a shortcircuit. The audio amplifiers final stage in M radios where often done with transistors that had a current limit protection circuit to keep the current within the transistors specification and where impossible to blow. The times there where no speaker audio it most of the times where a blown speaker coil or a smd capacitor gone short circuit or a leaky el-lyt capacitor.

/Ubbe

 

[Skypilot007]

I wish the scanner manufactures would stop providing inferior products to their customers by short cutting their designs and put a real audio output circuit in these scanners. 500mW or even 1 watt is pathetic. 3- 5 watts would work in most applications and make most of the available speakers happy.

Audio output from GRE/Whistler and Uniden has been extremely poor for a long time and they have done nothing about it. Not enough power and poor audio filtering equals crap scanner audio. As much as these scanners cost now it is very disappointing to hear audio that sounds like some sort of Chinese made toy. Portables included.

 

[n4jri]

I wish the scanner manufactures would stop providing inferior products to their customers by short cutting their designs and put a real audio output circuit in these scanners. 500mW or even 1 watt is pathetic. 3- 5 watts would work in most applications and make most of the available speakers happy.



Audio output from GRE/Whistler and Uniden has been extremely poor for a long time and they have done nothing about it. Not enough power and poor audio filtering equals crap scanner audio. As much as these scanners cost now it is very disappointing to hear audio that sounds like some sort of Chinese made toy. Portables included.

I've also been disappointed in the output of the PSR600 & it's various clones. Audio can make the display flicker like there's some sort of grounding problem--or other Kirchoff type issue. Amplified speakers work well in producing solid audio while keeping the radios internal audio at low drive. Escort makes an amplified speaker for its radar detectors that is very small with good output power, and keeps even the air band sounding nice and crisp. Also VERY compact. Bought mine a couple years ago on Amazon.

73/Allen (N4JRI)


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