Klipsch ACT-3 ABM, ACT-3 User Manual

acurusacurus

by Mondial

Advanced Bass Management upgrade

for the ACT 3

Contents

Introduction ............................................................................................................................................. 2

Features ................................................................................................................................................... 2

Section 1: Speaker Settings....................................................................................................................... 3

General Operation ................................................................................................................................3

Section 2: Crossover Settings ................................................................................................................... 4

Section 3: Dolby Digital........................................................................................................................... 4

Quick Setup Guide: Stereo Mode.............................................................................................................. 5

Quick Setup Guide: Dolby Digital (Pro-Logic).......................................................................................... 6

ACT-3 Advanced Bass Management System

Introduction

The Advanced Bass Management upgrade option for the ACT-3 surround sound processor provides even more flexible Bass Management, for those systems that require it. As Dolby is a company that licenses its technologies for components that are sold to a broad spectrum of consumers, it is essential that there remain compatibility within the products that they approve. In the case of Bass Management, this compatibility refers to a speaker’s ability to handle a full range signal without damage.

Dolby Digital contains an extra, .1, or LFE channel, which is a limited bandwidth (20Hz-120Hz) channel. Dolby recommends that this channel only contain information below 80Hz whenever possible. A system can have a subwoofer that only reproduces the LFE channel, or the subwoofer can reproduce the LFE channel, as well as bass from other channels in the system, that may not be as adept at reproducing lower frequencies. The function of Bass Management is to redirect these low frequencies, when necessary, to speakers that are better designed to handle them, such as the subwoofer. Within this document, LFE refers to the .1 channel provided by a Dolby Digital soundtrack. Subwoofer will refer to the subwoofer output as a whole, whether it contains just the LFE channel or a downmix of information from other speakers as well.

We understand that not all speakers are capable of reproducing a full range signal, however we also understand that most speakers that will be present in a high end system will be capable of handling a full range signal without any detrimental effects. This was the concept of Configuration 0 in the original ACT-3 Bass Management options. Configuration 0 allows you to run a full range signal to each speaker, while also sending this signal to the subwoofer to be reproduced. Once the subwoofer’s crossover is properly set to blend with the five main speakers, the resulting sound is the most complete and full sound you will obtain from a system leaving virtually no frequencies unheard.

Although ideal in most cases, the inability to make adjustments to the original Bass Management scheme limits its flexibility and compatibility in certain situations. Systems that do not contain subwoofers, contain passive subwoofers that do not have crossovers, or contain a center and/or rear speakers that are small and unable to handle a full range signal are not able to offer the best sound the ACT-3 has to offer. These Bass Management advancements are ideal for these situations. As we offer this as an after-market upgrade to the existing system, we also have the ability to offer some features that we feel are necessary, such as the ability to optimize the system by mode, instead of just by the type of speakers in the system.

Features

• Adjustable low pass and high pass filters with low crossover points for larger speakers

• Automatic optimization depending on mode

• Separate Bass Mode setting for Stereo

• Subwoofer output can be defined as LFE only, or LFE plus a downmix of all channels for

use as a “true subwoofer”

• Subwoofer output can be full range, or low pass filtered

• LFE summer for 5.0 DTS soundtracks

• Digital Input Memorization

Section 1: Speaker Settings General Operation

The Bass Management system is accessed in the same manner as the previous system was. You must be in the “Test Setup” mode, before you can make adjustments to the Bass Management options. With the new system, you have the ability to have separate settings for Stereo listening and the surround modes (Dolby Digital, and Pro-Logic). The Bass Management system is not utilized during DTS (as is suggested by DTS) , or DSP mode operation allowing full range signals to all channels. The separate settings include high pass/low pass filters, as well as the usual level adjustments. In Stereo and Pro-Logic, the subwoofer will always be available(previously, using a Bass Configuration where the subwoofer was LFE only, eliminated the subwoofer in Stereo and Pro-Logic) . Setting the Subwoofer to NO lowers the volume to 0.

While in the desired mode, press the Test button, and then press the B.Modes button to access the adjustments. Select the desired speaker by pressing the corresponding button in the speaker selection grid in the middle of the remote. (See Above)

For each of the five main speakers you will have the choice of No Crossover, or With Crossover. Selecting No Crossover sends a full range signal to that set of speakers. Selecting With Crossover sends the signal for that channel through a high pass filter, of which the crossover frequency is selectable. Press the LVL DN key to set the speaker up for a crossover. The speakers are automatically set up in pairs. For example, if you change the Left Front speaker to With Crossover, when you access the Right Front speaker it will already be set to With Crossover.

The Subwoofer can be set to either YES, or NO. The LVL DN button corresponds to YES. Different subwoofer settings will have different effects on the overall Bass Management settings, especially in Dolby Digital. A subwoofer setting of NO, in Dolby Digital, requires that the LFE channel be distributed to the Large speakers in the system. When the LFE channel is rerouted to another channel in the system, the channel it is rerouted to requires attenuation according to Dolby standards. This is done to accommodate for the worst case scenario in which you have a 0dB Full Scale signal in both the LFE channel, as well as the channel the signal is rerouted to. If the system were to avoid attenuating the channel, an overload would occur in the DSP chip which could result in the damage of your amplifiers and/or loudspeakers. We have limited the attenuation to the minimum amount necessary.

There is essentially no down side to this attenuation other than the loss of overall gain. However, it is not always necessary to reproduce the LFE channel. The LFE channel in Dolby Digital normally contains no extra information. Its presence is merely to augment the bass response for speakers which cannot necessarily handle a full range (20 Hz – 20 kHz) signal.

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