פרוססורים לשידור

Audio processing features

Currently, Stereo Tool offers the following sound processing options:

Declipper

A unique filter only found in one other processor. It finds and restores clipping (distortion caused by too loud input levels) which is present in most music from the last two decades. See the Perfect Declipper site for more info.

Hiss removal filter

Stereo Tool contains a powerful hiss reduction filter that has almost no effect on the rest of the sound. Especially useful when playing older songs or when a lot of volume compression is used.

FM hiss removal filter

This is useful when the input signal comes from an FM transmitter, for example when re-broadcasting the sound from an FM station.

Automatic Gain Control (AGC)

This AGC keeps all the sounds below a defined level. Different from many traditional processors, the AGC in Stereo Tool is not peak level based but acts on how loud something sounds to human hearing.

10-band multiband compressor / limiter / clipper

If one song contains a lot of bass, and the next contains a lot of treble, this filter can make them sound equal. Older or bad quality recordings can be made to sound closer to the sound of modern CD's, which generally sounds much better on a wide range of playback equipment.

Phasing error (AZIMUTH) correction filter.

Old tape recordings and many cheap CDs often suffer from severe phasing errors. These phasing errors can make listening very unpleasant, and when the phasing error changes over time the sound can seem to "float" around you. It can also cause severe artifacts when converting the sound to mono or when playing it on a surround system. This filter automatically detects and repairs such errors. For FM transmissions this can reduce multipath distortion.

Stereo booster

This filter increases the existing stereo sound, unless it was already very loud, which makes the sound much fuller. It can be configured to not alter the total sound content.

Stereo to mono conversion

Converts stereo to mono without removing sounds that normally cancel out each other. So the mono sound still sounds just as full and powerful as the original stereo sound.

Bass booster

This filter increases the bass level without increasing the maximum amplitude of the bass.

Final limiter

The Stereo Tool Final Limiter can transparantly remove short spikes in the signal - so with nearly no effect on the sound.

Distortion masking Loudness filter

This filter can make sounds up to 12 dB louder, without causing higher amplitude peaks in the signal, with little effect on the sound. Especially useful for radio stations that want to sound loud.

Lowpass filter

The extremely steep phase linear lowpass filter can be used to cut off frequencies that cannot be broadcast (streaming audio, FM transmitter, AM transmitter).

FM transmitter features

Stereo Tool can generate an MPX signal, including stereo and RDS data, which can be sent to the FM transmitter using a good quality 192 kHz capable sound card. No separate hardware stereo coder or hardware RDS encoder is needed.

The following FM transmitter specific options are provided:

FM pre-emphasis filter

Pre-emphasizes the sound, which is needed for FM transmissions. All the audio processing steps will take the pre-emphasis into account, meaning that pre-emphasizing does not cause spikes in the signal, if the Final limter or Loudness is used.

Stereo Tool can output both the pre-emphasized and the de-emphasized sound.

FM stereo encoder

The software FM stereo encoder generates a high quality MPX signal including stereo information, which can be fed directly into a (mono) FM transmitter.

FM RDS encoder

The software RDS encoder enables broadcasting RDS texts without using a separate hardware RDS encoder.

Composite limiter

A composite limiter is available in Stereo Tool to squeeze out the last 0.5 dB of extra loudness with no effect on the quality. The stereo pilot tone and RDS signal are NOT affected by this filter, so the MPX signal that comes out complies perfectly to the standards.

ITU-R.BS-412 limiter

Mandatory for several European countries. The BS412 limiter in Stereo Tool has nearly no effect on the sound (no extra clipping, no pumping, no gain riding), but still keeps the output level extremely close to the allowed maximum.

ITU-R SM.1268 (Stokkemask) clipper

Mandatory for the Netherlands. Reduces extreme stereo separation, and can therefore also be used to reduce multipath distortion.

פרוססור שידור מקצועי מבוסס תוכנה.

Stereo Tool