JL Audio E6450 owner manual Input Section, Amplifier Controls, Filter Controls

INPUT SECTION

The e6450’s input section allows you to send signal to the amplifier section through the use of two, four or six inputs and offers two distinct input connection options.These are:

1)Three pairs of traditional RCA type connections designed to accept input from source units with line level outputs.

2)An eight-pin connector designed to accept input from amplified sources such as factory source units or source units not equipped with line level outputs. Channels 5 & 6 of the e6450 do not have discrete inputs on this connector. However, signal from channels 1 & 2 and channels 3 & 4 can be summed and sent to channels 5 & 6 when “SUM” is selected with the “Input Mode” switch in the Channel 5 & 6 Controls section.

If you wish to send six discrete channels into the e6450, simply use all six inputs and set the “Input Mode” switch in the “Channel 5 & 6 Controls” section to “Discrete”.This will most commonly be accomplished by using the six RCA type connections (it is possible to use the eight-pin connector with amplified signals for input into channels 1, 2, 3 & 4 and RCA type connections for input into channels 5

&6, however, most source units with a dedicated subwoofer output will also have at least one pair of full range outputs).

If you wish to feed all six channels by using only four channels of full-range input, set the “Input

Mode” switch in the “Channel 5 & 6 Controls” section to “SUM” and use only the inputs to channels 1, 2, 3 & 4.

If you wish to feed all six channels by using two channels of full-range input and two channels of low- frequency input (subwoofer output from the source unit), set the “Input Mode” switch in the “Channel 5

&6 Controls” section to “Discrete”. It will be necessary to split the full-range signals with

y-adaptors and feed these signals into the inputs to channels 1, 2, 3 & 4.The dedicated subwoofer signal should be sent to channels 5 & 6.

If you wish to use only two channels of input to deliver signal to all six amplifier channels, it will be necessary to split the two signals with y-adaptors and feed these signals into the inputs to channels 1, 2, 3 & 4. Set the “Input Mode” switch in the “Channel 5 & 6 Controls” section to “SUM” and use only the inputs to channels 1, 2, 3 & 4.

The same input connection option does not need to be used for each channel pair.The “Input Sens.” adjustment is independent for each channel pair and must be adjusted based on input level and the impedance of the load on that pair of channels. Specific “Input Sens.” adjustment information is given in Appendix A (page 12).

AMPLIFIER CONTROLS

Input Sensitivity

These controls, labeled “Input Sens.”,can be

used to match the source unit's output voltage(s) to each input stage of the e6450 for maximum clean output. Rotating an “Input Sens.” control clockwise will result in higher sensitivity (louder for a given input voltage). Rotating an “Input Sens.” control counter-clockwise will result in lower sensitivity (quieter for a given input voltage.)

To properly set the amplifier for maximum clean output, please refer to Appendix A (page 12) in this manual. After using this procedure, you can then adjust any or all “Input Sens.” levels downward if this is required to achieve the desired system balance.

Do not increase any “Input Sens.” setting for any channel(s) of any amplifier in the system beyond the maximum level established during the procedure outlined in Appendix A (page 12). Doing so will result in audible distortion and possible speaker damage.

Filter Controls

Most speakers are not designed to reproduce the full range of frequencies audible by the human ear. For this reason, most speaker systems are comprised of multiple speakers, each dedicated to reproducing a specific frequency range. Filters are used to select which frequency range is sent to each section of a speaker system.The division of frequency ranges to different speakers can be done with passive filters (coils and/or capacitors between the amplifier outputs and the speakers), which are acceptable and commonly used for filtering between mids and tweeters. Filtering between subwoofer systems and satellite speaker systems is best done with active filters, which cut off frequency content at the input to the amplifier. Active filters are more stable than passive filters and do not introduce extraneous resistance, which can degrade subwoofer performance.

The active filter built into each channel of the e6450 can be used to eliminate potentially harmful and/or undesired frequencies from making their way through the amplifier sections to the speaker(s).This serves to improve tonal balance and to avoid distortion and possible speaker failure. Correct use of these filters can substantially increase the longevity and fidelity of your audio system.

1)“Filter Mode” Control: The e6450 employs a 12dB per octave filter for each pair of channels (one filter for channels 1&2, another filter for channels 3&4 and another filter for channels 5&6). Each of these filters can be configured independently into one of two filter types or defeated completely by way of the three-position “Filter Mode” switches:

“Off”: Defeats the filter completely, allowing the full range of frequencies present at the inputs to feed the amplifier.This is useful for systems utilizing outboard crossovers or requiring full-range reproduction from one, two or all of the e6450’s channel pairs.

“LP” (Low-Pass): Configures the filter to attenuate frequencies above the selected filter frequency at a rate of 12dB per octave.This is useful for connection of subwoofer(s) to one, two or all of the e6450’s channel pairs in a bi-amplified system. “HP” (High-Pass): Configures the filter to attenuate frequencies below the selected filter frequency at a rate of 12dB per octave.This is useful for connection of component speakers to one, two or all of the e6450’s channel pairs in a bi-amplified system.

2)“Filter Freq. (Hz)” The filter frequency markings surrounding this rotary control are for reference purposes and are generally accurate to within 1/3 octave or better. If you would like to select the filter cutoff frequency with a higher level of precision, consult the chart in Appendix B (page 13).

Tuning Hint: If you are using the e6450 to drive a subwoofer system (“LP” mode), a component satellite speaker system (“HP” mode) or both,

100 Hz is a good baseline “Filter Freq. (Hz)” setting. After properly adjusting the “Input Sens.”, as outlined in Appendix A (page 12), you can fine tune the “Filter Freq. (Hz)” control to achieve the desired system frequency response.

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