Tannoy ACTIVE STUDIO MONITORS Bass Management, LFE Low Pass Filter, LFE Gain, Polarity, Phase

A C T I V E S T U D I O M O N I T O R S

Bass Management

Bass management (sometimes called bass redirection) is a very important and useful tool. With conventional studio monitors external electronics is required to achieve bass management. It is in general an absolute necessity if you want to make a multi-channel set-up in a small room.The bass management system is designed to subtract the bass contents of all main channels and reproduce this by the use of a subwoofer. iDP™ systems provide a number of possible crossover frequencies that can be determined by the user.

In a basic 2-channel or 5-channel set-up (e.g. ITU-775) a sub-woofer is not specified and is not required. But producing audio tracks to be played back on consumer equipment, one has to ensure that the mix will sound right in this situation. Many consumer set-ups contain a subwoofer, hence it is very important to check what the summing of the bass is like.

If the program material basically is out of phase, the bass will be cancelled when summed electrically. But this is not the case if the bass signals are reproduced by the main monitors and summed acoustically.

Important iDP™ parameters to consider when using Bass Management:-

LFE Low Pass Filter

Switches on/off a very steep (7th order) low pass filter at 120 Hz. When switched on, the LFE signal filters out content above 120 Hz. This filter should be switched on when a media encoder is not in use and switch it off when your signal is being played back through a decoder (Most media encoders - DTS, Dolby etc. - employ an anti-aliasing low-pass filter. Therefore in a production environment it is important use this filter when monitoring the LFE channel in order to access how the signal will sound after encoding / decoding (in a domestic or cinema environment).

LFE Gain

Range: 0 to +14dB

The LFE channel can be boosted by up to 18dB using this parameter.

Polarity

Range: 0 or 180º

If the Subwoofer is correctly placed, setting the Polarity parameter at 180º should result in a full Phase cancellation at the set cross over frequency. If this is not the case – the Phase parameter described below should be adjusted.

Phase

Range: 0 to 180º Phase Introduction

The integration of the TS112 iDP™ or TS212 iDP™subwoofer with the Precision iDP™ monitors requires on-site tuning for best results. Apart from level calibration and choosing a Bass Management Crossover

(X-over) frequency, the issue of phase alignment remains.

For this purpose, the subwoofer has a 0-180 degree phase adjustment (in 5 degree steps) and a Phase Reverse function. The optimal setting of these parameters will depend on several factors:

1.Room acoustics

2.Placement of monitors and listening position

3.Choice of crossover frequency

4.Whether the Precision 6 iDP™ or Precision 8 iDP™ Monitor is being used.

Phase settings are automatically saved and linked to the currently selected Crossover frequency. Phase settings are Global settings and are therefore are not saved with individual presets.

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