EDM transmitters

[stanward]

Everyone, thank you for your responses. I want to know, what level you are all adjusting the Audio L&R pots?

If you are looking at the pots from the outside of the enclosure, at what position are they?

Mines are pointing at 12'o clock (supposedly half way).

[jeffl]

From the EDM team today on the EDM Yahoo group. Maybe this will help some people.


"It is amazing how often we still get people complaining about audio
distortion with their EDM units. Most of these complaints come from
people who failed to read their operating manual carefully.
Please " After trying it your way - Try reading the instruction manual"

If your audio source is not fitted with two RCA jacks, you are most
probably dealing with high level audio which may overdrive the EDM's
audio inputs.
This may (and often do) produce severe distortion or, like some
incorrectly call it "static"

We recommend one of the following or similar products normally available
at various electronics stores.

http://www.radioshack.com/product/index.jsp?productId=2102975
<http://www.radioshack.com/product/index.jsp?productId=2102975> or

http://www.dealextreme.com/p/3-5mm-to-rca-stereo-audio-cable-with-volume
-controller-2650
<http://www.dealextreme.com/p/3-5mm-to-rca-stereo-audio-cable-with-volum
e-controller-2650>

EDM Team"

[Greg Young]

stanward wrote:

Wait, the green audio out jack is a line-level. So that couldn't cause the distortion.

I also changed the audio cables, etc. Same sound. Also, the sound quality is the same as my Whole House Transmitter, which is terrible.

Hi Stan:

Yes mine is directly connected to the pc's sound card line level out.

That being said, I forgot to check the pc's audio output levels this year (I totally forgot I had changed them for some digital hf work I was doing over the summer). I didn't bother to listen on a radio, figuring nothing had changed from previous years.

On opening night my sister said "your left outside speaker is shot. I heard static from time to time".

The speakers are fed from a receiver tuned to 104.9, the freq. I transmit on. I checked the pc speakers which sounded great, but sure enough when I listened on a portable FM radio, I heard the "static" which was actually was distorted audio on the peaks of the audio.

I opened pc audio control panel, and dropped the audio level about 1 or 2 dB (estimated), and its been fine ever since.

Since both transmitters have poor sounding audio, I think you just identified your issue - too much audio coming out of the line level output of your sound card!

Go into your audio control panel, make sure you are in the playback section (as opposed to recording), and drop the audio level of the wave/mp3 by lowering the sldier a notch, or two. Then take another listen.

Ideally you should listen while you make th change. If it's the audio, as it seems to be, you will hear a marked difference!

Good luck, and let us know how you make out....

Greg

BTW folks, you can vary the level of the "line-out" from a soundcard. Some think you can't because it's "line level", but you can adjust line level. I do it when I run different audio gear hooked up to the PC, as some require less than others. I just have to remember not to forget to recheck the levels!

[Greg Young]

stanward wrote:

Everyone, thank you for your responses. I want to know, what level you are all adjusting the Audio L&R pots?

If you are looking at the pots from the outside of the enclosure, at what position are they?

Mines are pointing at 12'o clock (supposedly half way).

Those are set at the factory for a standard line level input. I would suggest you vary the levels coming out from the pc, and leave those pots in the transmitter where they were factory set.

[Guest Don Gillespie]

Greg Young wrote:

stanward wrote:

Wait, the green audio out jack is a line-level. So that couldn't cause the distortion.

I also changed the audio cables, etc. Same sound. Also, the sound quality is the same as my Whole House Transmitter, which is terrible.

Hi Stan:

Yes mine is directly connected to the pc's sound card line level out.

That being said, I forgot to check the pc's audio output levels this year (I totally forgot I had changed them for some digital hf work I was doing over the summer). I didn't bother to listen on a radio, figuring nothing had changed from previous years.

On opening night my sister said "your left outside speaker is shot. I heard static from time to time".

The speakers are fed from a receiver tuned to 104.9, the freq. I transmit on. I checked the pc speakers which sounded great, but sure enough when I listened on a portable FM radio, I heard the "static" which was actually was distorted audio on the peaks of the audio.

I opened pc audio control panel, and dropped the audio level about 1 or 2 dB (estimated), and its been fine ever since.

Since both transmitters have poor sounding audio, I think you just identified your issue - too much audio coming out of the line level output of your sound card!

Go into your audio control panel, make sure you are in the playback section (as opposed to recording), and drop the audio level of the wave/mp3 by lowering the sldier a notch, or two. Then take another listen.

Ideally you should listen while you make th change. If it's the audio, as it seems to be, you will hear a marked difference!

Good luck, and let us know how you make out....

Greg

BTW folks, you can vary the level of the "line-out" from a soundcard. Some think you can't because it's "line level", but you can adjust line level. I do it when I run different audio gear hooked up to the PC, as some require less than others. I just have to remember not to forget to recheck the levels!

Greg let me get this straight I am running my shows through my PC I have my EDM hooked up to the headphone jack on my PC,my stereo receiver is hooked up to the back of my PC, should I be hooking my EDM up the the audio source on the back of my computer? I too am experiencing static when listening to my shows but not all the time. I read the manual about four times and maybe I am not reading it right, I am not that computer savy enough to get by I guess.

[Greg Young]

Don I would definitely recommend hooking the line level out from your soundcard to the inputs on your EDM. You can get a ministereo plug to dual RCA jacks cord from R Shack.

As to the hooking up receiver you have 2 basic options:

1) you could get a Y audio connector to split the audio output of your pc's soundcard to feed both the receiver and the EDM, but you risk ground loops, and other sources of noise/interference with that type of arrangement. My Ramsey 100B seems fairly immune to any hum/noise, etc, but I notice my EDM is much more prone to that if care is not taken in how it is connected, and where it is located.

OR

2) you could do what I do.. have the receiver tuned to your EDM's frequency, and get the signal that way. My receiver is located elsewhere in the house (close to the outside speakers to avoid long runs of speaker wire), which moves its electronics away from the pc and EDM/Ramsey 100B. Bottom line is no noise/interference from close positioning/interconnection of different pieces of electronics.

I started out with the option 1 when I first started using a transmitter, but after one season switched to option 2, which I have stayed with ever since.

Greg

[stanward]

Hi Greg,

Thanks for your responses. I tried to make the volume louder by adjusting the PC's sound level, but that created more distortion.

Can I adjust the EDM Audio L&R pots instead to make it louder?

Currently, I have my PC sound level at 50, which the highest is 100. So I'm hoping half way is a safe level.

Greg Young wrote:

Those are set at the factory for a standard line level input. I would suggest you vary the levels coming out from the pc, and leave those pots in the transmitter where they were factory set.

[Guest Don Gillespie]

Greg Young wrote:

Don I would definitely recommend hooking the line level out from your soundcard to the inputs on your EDM. You can get a ministereo plug to dual RCA jacks cord from R Shack. this I have

As to the hooking up receiver you have 2 basic options:

1) you could get a Y audio connector to split the audio output of your pc's soundcard to feed both the receiver and the EDM, but you risk ground loops, and other sources of noise/interference with that type of arrangement. My Ramsey 100B seems fairly immune to any hum/noise, etc, but I notice my EDM is much more prone to that if care is not taken in how it is connected, and where it is located.

OR

2) you could do what I do.. have the receiver tuned to your EDM's frequency, and get the signal that way. My receiver is located elsewhere in the house (close to the outside speakers to avoid long runs of speaker wire), which moves its electronics away from the pc and EDM/Ramsey 100B. Bottom line is no noise/interference from close positioning/interconnection of different pieces of electronics. my receiver is very close to my PC a couple of feet on a shelf in the office will try to see if it can pick up the frequency and eliminate the plug to the headphone jack

I started out with the option 1 when I first started using a transmitter, but after one season switched to option 2, which I have stayed with ever since.

Greg

thanks Greg

[Greg Young]

stanward wrote:

Hi Greg,

Thanks for your responses. I tried to make the volume louder by adjusting the PC's sound level, but that created more distortion.

Can I adjust the EDM Audio L&R pots instead to make it louder?

Currently, I have my PC sound level at 50, which the highest is 100. So I'm hoping half way is a safe level.

Greg Young wrote:

Those are set at the factory for a standard line level input. I would suggest you vary the levels coming out from the pc, and leave those pots in the transmitter where they were factory set.

Stan if you do that, it will also increase the distortion. It doesn't matter if you increase the input audio level via inputs in the transmitter, or via the audio generator (a pc in this case). Too high a level will cause distortion either way.

To minimize hum, etc while maximizing volume out what you could do is to leave the pc's output volume a little high, and then decrease the audio input using both pots in the transmitter.

That being said, those levels should have been set to standard at the factory and should not need to be adjusted. I recommend those not be adjusted, without using proper test equipment (a signal generator/oscilloscope in this case) to see what audio levels are going into, and what the rf looks like coming out from your transmitter.

When you input too high a level of audio into a FM transmitter, in addition to the audible audio distortion, you risk over deviating the output signal which causes "clipping", and a signal that potentially will cause interference to signals on adjacent frequencies, and/or result in radio frequency interference to other electronic devices in your immediate locality.

I run my pc's audio output level at the 5th "notch" on a scale of 7 "notches" that XP shows in the audio control panel, which is a little more than 50%. That will vary somewhat depending on your specific soundcard, pc setup, etc

[taybrynn]

I would use line out on the computer (not headphone out) and adjust the volume on the computer, not on the EDM. If you invest in something like Breakaway audio enhancer (the $30 version) ... it has an FM mode which enhances the sound even further.

[Faluzure]

Thanks for this guys. I'm a newbie doing research and I think i'll go with the EDM rather than that WH that's on Light-o-Rama's website.

[taybrynn]

there is no comparison ... the WH is garbage by comparison