BCD436HP/BCD536HP: Level Volume Audio Level Help

[AB8E]

OK Question:

I have to have a separate, volume level boost/cut for the audio on my BCD436 & 536HP's..

The reason is because you have different people with very different voice's and audio levels.
You have little ladies at dispatch and big loud state troopers at the same time.
So I turn the volume up in order to hear the low audio voices then the loud audio blows up as distortion.

Is there anyway Uniden can add something like that in the next update or maybe an add-on for additional price?

Or would that be complete additional circuitry that would need to be added to the next generations of the Home Patrol Product Line ?

 

[jonwienke]

AGC is supposed to solve that, but is mostly non-functional. It could probably be fixed via firmware but Uniden doesn't seem interested in doing so.

 

[AB8E]

This is what I have to use in order to make it happen.
I listen to Radio Reference based scanner transmissions and it's pretty obvious that no one cares
but is a real pain to listen specially with headphones.
Uniden could use it as a marketing strategy for internet feeds if nothing else.

 

[ofd8001]

This syndrome isn't confined to just scanning. It happens on "regular" system radios too. Folks talk in low voices or hold their microphones too far away. Then you got those who get a little louder than needed.

 

[AB8E]

Your right... It has since forever caused problems when you want to monitor on about everything. I'm just saying that a manufacture needs to step up and make this happen.

 

[W8RMH]

This occurs on the actual two-way radios as well and has gotten worse with the advent of digital. It's all about the lack of proper training on how to talk into and hold a radio.

 

[AB8E]

Yes...The different voices, too close, one louder than others, also the microphones have
different sensitivity also.
I actually have the problem solved but I have to have this additional system in place.
So I run this systems audio output into a bluetooth transmitter then TX to a bluetooth rx speaker so I can listen to my scanner at smooth volume levels.

 

[majoco]

You have to remember that a lot of 'professional' systems have audio levelling circuits to fix that exact problem - if you want to fix it yourself you will have to do the same. RF AGC in your receiver won't fix it at all. Also audio levels will change depending upon the mode, AM, FM or NFM will all vary in audio recovery.

 

[Ubbe]

The BCDx36HP already have automatic audio level control but it is set to work very subtle and we have not been given access to change the parameters, as we can on some older Uniden scanners. The DSP are an advanced chip and everything is in place to correct the issue with different audio levels, Attack-Decay-Release-Level settings and even bass/treble, but Uniden have decided to not have it user accessable.

/Ubbe

 

[jonwienke]

RF AGC in your receiver won't fix it at all.

x36 scanners have separate on/off toggles for digital and analog audio AGC. They just don't do much.

 

[AB8E]

The BCDx36HP already have automatic audio level control but it is set to work very subtle and we have not been given access to change the parameters, as we can on some older Uniden scanners. The DSP are an advanced chip and everything is in place to correct the issue with different audio levels, Attack-Decay-Release-Level settings and even bass/treble, but Uniden have decided to not have it user accessable.

/Ubbe

This is what I am bringing to Unidens attention.
We want the ability to control the overall audio level to be able to monitor better and use there products as a scanner feed so it will sound better and be easier to control.
Right now We have to take a $5-6 hundred product and add another 2-3 hundred $$ to do this.
Why... $$$$
Surely there will be a scanner manufacture to take this idea an run with it..
Maybe not Uniden.... Maybe one of there competitors will do this.
We Need this !!!

 

[KR4BD]

Many years ago, I had a similar problem with wildly varying audio levels with my home stereo system, particularly with CD playback. Some CDs have very high audio levels and others had exceptionally low levels. It was a real pain to constantly get up to adjust the volume so you could just be able to hear some low level CDs or LOWER the audio to prevent my windows from being blown out on the loud ones. I searched the internet and found a GREAT product for about $40. Now ALL my CDs have the same level of loudness. It was made by Brookline Technologies (Model 301E Volume Stabilizer). Now I can sit in my LazyBoy for hours while my CD player spits out multi CDs with stable, level audio levels coming from the speakers. It’s a black box — a bit bigger than a pack of cigarettes. It connects between the CD player “line output” and the tuner/amplifier.

Maybe something like this could be adapted for scanner use.

 

[AB8E]

Many years ago, I had a similar problem with wildly varying audio levels with my home stereo system, particularly with CD playback. Some CDs have very high audio levels and others had exceptionally low levels. It was a real pain to constantly get up to adjust the volume so you could just be able to hear some low level CDs or lower the audio to prevent my windows from being blown out on the loud ones. I searched the internet and found a GREAT product for about $40. Now ALL my CDs have the same level of loudness. It’s called a Phono Pre Amp with RIAA EQ (Volumn Stabilizer). It was distributed by a firm called Applied Research and Technology (ART). It’s a small black box that connects and adjusts the stereo line levels between the CD player and Tuner/Amplifier. It works great. Now I can sit (and stay) in my lazy boy while my MultiCD player chews through various CDs —all with equal sound levels!

Perhaps something like this could be adapted to a scanner?

Yes notice my photos in the beginning of this thread. I have the same thing connected to my system.
But this is in addition to spending 5-6 hundred $$ then having to spend more $$ to make it work correctly.
Then if you have the bcd436hp & you want to take it as an HT and have to drag along all this stuff..
What I'm saying Someone ( Scanner manufacture ) fix it and i will pay for it..
It's there make it happen..

 

[KR4BD]

Please check my edited version...not the one you copied. I originally cited my phone pre-amp (another black box!). That unit does nothing for volume stabilization.

 

[ScannerSK]

It's possible to slightly overdrive the input on one of the amplification stages in the audio section (the final stage would work best) to even out the audio. The loudest audio would come across just a little distorted (however still very tolerable) while the weaker sounds would be increased in volume to more evenly match the loudest sounds in amplitude.

I looked around inside the 436 a little to locate the amplification sections. One section is covered in epoxy which does not help. The other stages of amplification appear to be on a side of the board that cannot be accessed while the scanner is running (due to two boards being sandwiched together while running). I did not locate the precise IC that is being used as the main/final audio amplifier to drive the speaker. A little more time doing continuity testing and researching the various chips in more detail would certaily locate it (unless it is in the section covered in epoxy). If a person located this, it's just a matter of looking at the datasheet (if available) to determine the audio input pin and then increasing the signal into the input (typically by slightly lowering the series resistance across an existing resistor feeding into the input or slightly increasing the series capacitance across an existing capacitor feeding into the input thereby allowing more signal into the input to be amplified).

Without a service manual it takes more time than I had this evening however it might be worth looking at again down the road. It would be nice to have the sound more even in volume when one person is talking loud and another person talking soft on the same talkgroup. AGC makes basically no difference and is at best a "dead feature" that does not work and in my opinion is "false advertising" by Uniden.

Shawn

 

[Ubbe]

When I measure the RF sensitivity from my 536 it becomes very evident that the analog AGC is working as it should when adjusting the modulation level of the test tone and listening to the background noise at low RF levels. It's nothing wrong with it, it just needs to widen the parameters a bit. My BCT15 have access to those parameters in the user menu and does an excellent job to keep the audio level constant that are noticable if there suddenly are some high modulated signalling tones being heard.

The HP1 and HP2 are easy to access its service mode to alter the AGC parameters as there are only two buttons on the scanner, hold one down at start up and hold the other one down when the start screen comes up. There's probably a way to access that service mode even on the x36 scanners but for some reason Uniden wants to keep it a secret and doesn't let us know how to tailor our scanners to fit our personal taste.

It's a big difference compared to older scanners like the BC780 which has a huge variation in audio levels while scanning the same channels as the scanners with AGC features.

I don't have Bill Cheeks books but I would have thought that he had made a modification to insert some sort of a AGC/compressor circuit with a FET transistor to any scanners audio line before its volume control.

/Ubbe

 

[jonwienke]

I looked around inside the 436 a little to locate the amplification sections. One section is covered in epoxy which does not help. The other stages of amplification appear to be on a side of the board that cannot be accessed while the scanner is running (due to two boards being sandwiched together while running).

Tracing connections by visual inspection is a waste of time. The circuit boards (at least the front one) are multilayered sandwiches with 6 layers of connection traces. Look at the very bottom of the display board, and you can see each layer numbered at varying depths in the board.

 

[jim202]

All this conversation is doing is to point to the VERY POOR ability of the radio technicians to adjust the equipment correctly. Having been in this portion of the public safety communications for a really long time, I have been inside many dispatch centers around the country. I have seen first hand the poor work some of the supporting radio techs are doing with both the radios out in the field and the adjustments of the dispatch consoles.

I have pointed out to the radio shop owners of the poor, sloppy work their radio techs are doing. The owner's attitude is so what. They are looking for the call from the dispatch center so they can charge for a service call that they have created. The dispatch center manager gets to frustrated about these calls. My suggestion to them is to find another radio shop that cares and does good work. Problem is the radio shops in some parts of the country are far away and few to be found. So your stuck in the middle of a problem that is hard to resolve.

My suggestion is to stop paying the bill for the service call until the problem is resolved.

I know this isn't the solution to the comments in this thread, but I felt that you should have some feedback on the other side of the fence. This in some cases, is not an easy problem to solve with the audio levels all over the place between radios and different dispatch consoles.