Home Patrol Terrible Sound in Car

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OldDrunk

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I installed the HP1 in my car and connected it to the car's speakers using the auxiliary input. I had to use the headphone output on the HP1 to do it. My car does not have a line-level input. The sound is totally unacceptable. It's garbled and there is a lot of hissing to the point that it is almost unintelligible. Now, up until now, I had an old analog scanner connected to the car's audio in the exactly same way, using the exact same cable. The sound quality from this old scanner was MUCH better than from the HP1. It was loud and clear, with almost no hissing. So I went ahead and purchased an FM transmitter and connected it to the HP1. This improved the sound only a little bit. The audio is still very poor quality, with a lot of hissing, and is really not usable.

How do you guys have your HP1 connected to the car's audio? Any suggestions on how I can improve the sound quality?
 

Ensnared

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Garbled & Hissing

I installed the HP1 in my car and connected it to the car's speakers using the auxiliary input. I had to use the headphone output on the HP1 to do it. My car does not have a line-level input. The sound is totally unacceptable. It's garbled and there is a lot of hissing to the point that it is almost unintelligible. Now, up until now, I had an old analog scanner connected to the car's audio in the exactly same way, using the exact same cable. The sound quality from this old scanner was MUCH better than from the HP1. It was loud and clear, with almost no hissing. So I went ahead and purchased an FM transmitter and connected it to the HP1. This improved the sound only a little bit. The audio is still very poor quality, with a lot of hissing, and is really not usable.

How do you guys have your HP1 connected to the car's audio? Any suggestions on how I can improve the sound quality?
Let me ask you this question. Can you hear the NOAA on the radio? Does it come in clear?

I channel my radio through the auxiliary port on my Kenwood stereo all of the time.

What system are you trying to monitor, location?

I don't know whether you need to adjust your squelch setting. Do you know whether the frequencies you're monitoring are analog or digital? Garbled speech, when it is digital, can be two main things: a) dropped signals with robot-sounding transmissions, similar in ways to encryption; b) encryption being used.

If always use NOAA to check my analog reception.
 
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JMSuiter

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You may want to try using a ground loop isolator. Amazon I think sells one that you can use for 1/8" (headphone jack) outfits. Of course, before you invest in this option, you'll want to check what the last poster suggested, as your problem may be in reception, not connection. If the main issue you're having is with hissing, it's likely a connection problem. Unplug you're scanner from the car speakers and see if you're still having issues. If not, then you may need the isolator. Another troubleshoot, unplug the power to the scanner, but leave the sound plugged into the car speakers. If this clears it up, this is also a ground issue. If in any of these setups, you're still having issues, then it is a reception problem and you need to follow Ensnared's suggestions.
 

OldDrunk

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Thanks guys. I am sure the problem was not with reception. Also, it's not only the digital channels that sounded bad, but the analog also. So I went ahead an purchased the ground loop isolator. It did make a big difference. The audio went from totally unacceptable to borderline acceptable. Some channels are better than others, with the analog usually being better than digital. However, comparing the audio from just the analog channels to my old Yupiteru MVT-8000, the Yupiteru still sounded much better. The only times I had difficulty understanding the audio was always due to reception. What gives? Why does the audio from a 20 year old scanner sound so much better?
 

rwier

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......... Why does the audio from a 20 year old scanner sound so much better?
Unrelated to any specific device (clock radio, home stereo, scanner, megaphone, television, etc.), I believe a relationship exists between the quality of sound and the weight of the magnet/s used in the speaker assemblies. Wouldn't be surprised if the magnet/s in the old scanner are 2-4 times as heavy as the one/s in the new scanner. This belief is just from experience, as I know nothing about actual electronic circuitry.
 

N0UDG

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I installed the HP1 in my car and connected it to the car's speakers using the auxiliary input. I had to use the headphone output on the HP1 to do it. My car does not have a line-level input. The sound is totally unacceptable. It's garbled and there is a lot of hissing to the point that it is almost unintelligible. Now, up until now, I had an old analog scanner connected to the car's audio in the exactly same way, using the exact same cable. The sound quality from this old scanner was MUCH better than from the HP1. It was loud and clear, with almost no hissing. So I went ahead and purchased an FM transmitter and connected it to the HP1. This improved the sound only a little bit. The audio is still very poor quality, with a lot of hissing, and is really not usable.

How do you guys have your HP1 connected to the car's audio? Any suggestions on how I can improve the sound quality?
Some possibilities: (I will try not to repeat the good suggestions that the others have already given)

1. Is the cable you are using to connect the HP-1 to your Aux Input of your car a stereo cable?
Many scanner speaker outputs are Mono but the headphone and Line-Out are usually stereo.

2. Did you try the "Line Out" from your HP-1 to your Aux Input, just to see if it would work?

3. When you connected your "Headphone Out" of your HP-1 did you try adjusting the volume of the HP-1?

4. Have you checked your car's owner's manual for any adjustments or approved uses for your Aux Input?

5. What inputs were recommend for your FM transmitter (speaker out, headphone out, line out)?
If your car has an extendable antenna did you extend it?

6. Distortion & hiss can be a sign of overload (assuming your antenna, coaxial cable & connectors are still good). Radio Shack does sell a audio "Attenuation cable" but all the ones I have seen are mono so you will need two mono to stereo adapters to use it.

However, since you can turn the volume up and down I would think that should have took care of this problem, so I would hold off on the "attenuation cable" as having a low probability of helping at this point.

The suggestion to have you HP-1 on battery power and not hooked to the car power (just to try it out to see if it helps) is a good suggestion.
 

Gcom

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Several persons have reported having problem with external speakers connected to the Home Patrol . Check the forums. It appears it was designed to only drive headsets. I have experimented with amplified speakers and even the auxillary amp input on my car. It always has distortion. Some have reported having better luck running through a ground loop isolator(RadioShack) Ground loops are not typically a desirable circuit in audio applications. Guess it was for power saving. I can neither use my HP-1 at work in a IT enviroment or mobile due to it's low volume . Only at home.
 

N0UDG

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Several persons have reported having problem with external speakers connected to the Home Patrol . Check the forums. It appears it was designed to only drive headsets. I have experimented with amplified speakers and even the auxillary amp input on my car. It always has distortion. Some have reported having better luck running through a ground loop isolator(RadioShack) Ground loops are not typically a desirable circuit in audio applications. Guess it was for power saving. I can neither use my HP-1 at work in a IT enviroment or mobile due to it's low volume . Only at home.
This does appear to be the case, however, the HP-1 does have a "Line out" which my 396T, 396 XT or my new 436HP do not have. With that said I do not think the "Line out" can be used successfully to drive an external speaker amplified or not. Indeed, some people have claimed that they have used the headphone out of the HP-1 and an external amplified speaker with success. I know of a lot of people who were not so successfully.

I think all of the portable radios usually only have a "headphone out" which is a very weak audio amplifier (often measured in mW) with dropping resistors added to protect your hearing. So, in a way it does save Uniden money; money from a lawsuit from people who have had their hearing permanently damaged but I do not think it saves them money from a manufacturing standpoint.

Because the "headphone amplifier" is so weak if you turn it up much it will distort before you can get enough output to successfully drive some external devices properly. At least this has been my experience.
 

JamesO

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Might read this as well - http://forums.radioreference.com/uniden-scanners/284238-bcd536hp-external-speaker-connection-considerations-precautions.html

Seems that the audio amp design and output configuration varies and is important on how external speakers, amplified speakers, amplifiers, sound cars, Bluetooth A2DP devices are connected.

Some of the issue is the stereo connection that some of the jacks have, some it has to do with the Amp design, some it has to do with ground loops.

Seems to me that Uniden needs to write some form of Technical Bulletins and./or Application Note for connecting external speakers, amplified speakers, line amplifiers, sound cards and USB audio from the newer model scanners. This documentation should be broken down by scanner model number and explain how the outputs are wired, mono or stereo, the Amp design and specs/impedance requirements.

^ UPMan/,Uniden hint, hint, hint.

Best if it comes directly from the source rather than having one of the forum members backwards engineer this. A set of Technical Bulletins/Application Note for products might even help out Customer Service and head off a lot of workload. Just come up with a standardized format and likely you can use this same template across the products lines. I have some ideas if anyone is interested.
 
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JMSuiter

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OldDrunk said:
Thanks guys. I am sure the problem was not with reception. Also, it's not only the digital channels that sounded bad, but the analog also. So I went ahead an purchased the ground loop isolator. It did make a big difference. The audio went from totally unacceptable to borderline acceptable. Some channels are better than others, with the analog usually being better than digital. However, comparing the audio from just the analog channels to my old Yupiteru MVT-8000, the Yupiteru still sounded much better. The only times I had difficulty understanding the audio was always due to reception. What gives? Why does the audio from a 20 year old scanner sound so much better?
Not sure on why the older unit seems to work better, but the reason the isolator worked better on the analog is because the digital needs a higher signal quality to begin with.
 

OldDrunk

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Some possibilities: (I will try not to repeat the good suggestions that the others have already given)

1. Is the cable you are using to connect the HP-1 to your Aux Input of your car a stereo cable?
Many scanner speaker outputs are Mono but the headphone and Line-Out are usually stereo.

Yes, it is a stereo cable. I also tried to use a mono cable with a mono to stereo adapter in order to get the sound to come out of all four speakers, with the same result.


2. Did you try the "Line Out" from your HP-1 to your Aux Input, just to see if it would work?

I could not try this initially because the line-out on the HP-1 is a 2.5mm plug, while the Aux input in the car is a 3.5mm plug. I also did not think it would work because I assumed that the line-out does not provide any power, so it could not drive the speakers. However, I had nothing to lose, and since I tried everything else, I went ahead and bought a 2.5mm to 3.5mm stereo adapter. I then used it to connect the line-out from the HP-1 to the same Aux port in the car. It worked! I tried this without the ground loop isolator, and there was no hissing. The audio was loud and clear (as clear as can be on a digital channel). I can't say that I have an audio issue now, since the sound is as clear as that from the HP-1 speaker. And as I said, I no longer need the ground loop isolator which I was using with the headphone out to Aux in.


3. When you connected your "Headphone Out" of your HP-1 did you try adjusting the volume of the HP-1?

I tried adjusting the volume high and low, with no improvement.


4. Have you checked your car's owner's manual for any adjustments or approved uses for your Aux Input?

I did, and there were no instructions regarding the Aux input.


5. What inputs were recommend for your FM transmitter (speaker out, headphone out, line out)?
If your car has an extendable antenna did you extend it?

I stopped using the FM transmitter since the ground loop isolator greatly improved the sound quality.


6. Distortion & hiss can be a sign of overload (assuming your antenna, coaxial cable & connectors are still good). Radio Shack does sell a audio "Attenuation cable" but all the ones I have seen are mono so you will need two mono to stereo adapters to use it.

I don't think this is the problem. It looks like most of the issue was caused by a ground loop.

However, since you can turn the volume up and down I would think that should have took care of this problem, so I would hold off on the "attenuation cable" as having a low probability of helping at this point.

The suggestion to have you HP-1 on battery power and not hooked to the car power (just to try it out to see if it helps) is a good suggestion.
I tried running the HP-1 on battery power and plugged into the cigarette lighter. That made absolutely no difference.
 

SCPD

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hey

Areyou using the speaker jack the bigger hole or the smaller jack on the Hp-1?
If you are using the speaker jack,thats your problem !(judging by what you said YES)
Use the tiny jack that provides a set level to car stereos.
I forget if you need a stereo to mono jack adapter in there but I think so!it will look stupid ,so get a right angle adapter.
 
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