I've bought from here before and have been happy with the service, so as I'm after a RDS module and stereo coder I thought I'd seek your valued opinions.

Here's the RDS module - http://www.enigma-shop.com/index.php?op ... der-module

I already have an old NRG pro3 coder somewhere but it's huge, so this caught my eye - http://www.enigma-shop.com/index.php?op ... -broadcast

My pro 3 seems to produce quite distorted sound on some tunes with high frequencies like cymbals etc (raspy type crackle audio), so as the coder at Enigma states a frequency response of upto 15 kHz, am i right in thinking this will prevent this distortion or am I mistaken?

Both good modules but remember you have to disable any pre-emphasis on your driver before plugging these in or it won't sound right! Maybe that's the cause of your distortion?

The 15KHz limit is defined by the FM standards and is to stop L-R channel interference, it might be another reason you're getting that noise if the filtering in your current encoder isn't done right.

The RDS module is a good RDS, based on the Pira Micro RDS (MRDS1322) chip.
However for synchronization (RDS/Stereocoder), this version of the RDS is not capable to filter the pilot from the stereo signal (MPX), you have to apply the 19khz pilot separately to the RDS.
The SPI stereocoder in the link doesn’t has a separate 19kHz pilot output.
So synchronization is a challenge.

Stereocoder 15kHz audio filtering.
According to the European Telecommunication Standard (ETS) and in accordance with CCIR Recommendation 450-1;
Both AF channels shall be equipped with a 15 kHz low-pass filter. The attenuation of these filters shall be at least 40 dB at 19 kHz, referred to 15 kHz. The stop-band attenuation above 19 kHz shall be > 30 dB

I don’t think that the stereocoder complies to this.