Stereo Tool

Hi there,

I am sorry if this has been mentioned before, but as you can guess I am new here and this is my first post. I really need help with this!

I have been using Stereo Tool for around 2 years now, and really like what it does to the music (it makes music a lot more punchy and lively!!). I have recently got the RDS encoder working with my mini FM transmitter, along with the FM composite limiter too.

However, the mini FM transmitter has a built in stereo encoder, along with pre emphasis too, which means I have the FM composite limiter set around 100%, with the Pre Emphasis and the Stereo Encoder set to Off in Stereo Tool. If set it around 102%, the modulation is a lot tighter and isn't over modulated any more, but, because I don't need the stereo encoder on in Stereo Tool, this means the audio goes into mono. Unfortunately I can't switch off the Stereo Encoder or Pre Emphasis in the transmitter, as I would if I could.

So basically is there any way I can achieve tight modulation without using Stereo Tool's built in Stereo Encoder? To stop the audio from over modulating on FM I have to set the audio on the PC very quiet! If I switch on the Stereo Encoder in Stereo Tool, the 2 sort of fight with each other creating a phasey sort of sound.

Do I need to buy the full version of Stereo Tool as I only use the Free home version at the moment?

Thanks for reading
Jack

Hi..
Tight signal is because mpx clipper in stereo coder in Stereo Tool..in your transmitter is only stereo coder + pre-emphasis.
So, since you cannot turn off Stereo Coder / pre-emphasis in transmitter.. you can use "normal" output (L/R) from Stereo Tool and feed transmitter.. to get bit tighter mpx.. you can try to use Pre-emphasis for Normal output (0-30us).
Ofcourse you cannot have RDS from StereoTool this way.

I reccomend You to get transmitter with pure mpx input.
Also might be possible that yours already have it. You just need to find it. Except if it's build with "all-on-one-IC"

I suppose you just use the FM signal for yourself, "in house"? In that case tight modulation isn't that important. If you have listeners and want a tight modulation, you really need to get the stereo coder turned off - also, VERY bad things are probably happening to the RDS signal. (It's actually very surprising that you can get it to work at all).

Composite clipping is not possible without stereo coding - in the latest beta you'll see that the Composite button is grayed out when you disable stereo coding.

With a mono FM transmitter - even with the ultra-cheap (15 Euro / $ 20) battery powered ones with a reception range of around 50 meters - you should easily be able to beat nearly any FM station in loudness without overmodulating. (You do need a paid version for that, but you also need it for RDS).

Hi Hans and Bojcha

Thanks for your help.

Do you know any cheapy mono FM transmitter that will accept RDS and a modulated composite signal? A few I've tried have included Pre Emph and a built in 15kHz low pass limiter which was useless for RDS and just general messing around with. This one I have now does transmit RDS but it has built in Stereo Encoder (it lights up the Stereo beacon on the radio anyway) which you say needs to be done in Stereo Tool instead of in the mini FM transmitter (I can't switch it off unfortunately).

Thanks

I had one for a few years - battery powered, range of about 20-30 meters. Brand name was König. Cost about 15 euro at the time (I bought it when I wrote the stereo coder and RDS encoder, and both worked fine with it.)

Can you tell us the model or a link, because I'm looking for something and can not find something affordable with mpx input or at least that is cute.
Look on the website of Konig, but can not find. Tanks.

_________________
by GAP
"Less is More" (Bob Katz)

Sparky1010 this might be worth looking at:
eBay Link

It looks like a ripoff of the older Broadcast Warehouse 1 Watt PLL unit. Exacty the same layout. They also have the LCD for it too.

Clipper

Edit: Just noticed their site: http://store.rf-modules.com/category.php?id_category=37

Deleted post by DallasVickers

Welcome to the board. You can find affordable FM mono transmitter online, have a look to this to match the product with your existing model.
http://www.broadcastdepot.com/

Another thing you could try, if you know how to use soldering iron, is to crack open the transmitter and start poking around inside it. Alot of transmitter uses Rohm circuts BH1415 or BH1417. Not the best in the world, but their complete stereo transmitter circuts. On the output from pin 1-6 theres a mixer to create the mpx signal. Thats where you could put your own signal. If it aint Rohm based, there will most likely be some other circut that generates the mixed stereo encoded signal where you could insert a mpx signal.

I've been using this technice myself on BelkinTunecast transmitters and on 50$ chinese crappy transmitters.

Just be careful with the level out of the PC that runs stereotool, lover the output volume slider in windowz to something around 10 if you use the headphone output. Thats because the inserting of mpx happens after what-ever-kind-of limiter/agc that would be in the transmitter, and after any kind of leveladjustment. If oy dont do this, you might blow the transmitterpart in the box.

Even with this little hack, a TuneCast with external antenna easely blows atleast 50 meters further than it did and sound just as big as the top stations on the dail. You get controll of your own Pilot, RDS, and all the nice composite clipping and limiters thats in this nice tool starting with the letters Stereo...

Have fun

Edit: Pin 1 is an input, mpx mixed between pin 2 and 6.

Can you tell me what is the main roll mpx signal here and whatever you written here 1-6 pin to create the mpx signal and put own signal can you defined clearly???? because through mpx signal you can monitor on-air signal, compare more than one audio processors but how according to Mr. sparky1010 issues about "tight modulation without using Stereo Tool's built in Stereo Encoder? " can resolved.