Specifications

2.64

Applications Manual

Revision 1.11Prism Sound dScope Series III

5.2.1.6 Frequency Response, Bass Redirection

dScope Configuration:

Frequency Response Track 43-48.dsc

Track Number:

43-48

Corresponding AP Test File:

N/A

Duration:

60 sec (each track)

Test Signal Description:

-20dBFS sweep, 20Hz to 20kHz

(Sub 20Hz to 120Hz)

Channels:

L (track 43), C (track 44), R (track 45), Ls (track 46), Rs

(track 47), Sub (track 48)

Description

This test verifies frequency response, bass management and downmix levels for all downmix modes.

Test 1 assumes that all speakers are "small", so removes the low frequencies from the main

channels, adds them to the signal from the Sub, and the Sub channel outputs the sum of these

signals.

Test 2 applies bass redirection in the case that some of the main channel loudspeakers are "large"

and capable of low frequency reproduction. In this case the low frequencies are filtered from the

"small" speakers, summed together with the signal from the Sub, and reproduced by the "Large"

speakers (usually left and right).

Note: Some DVD players implement a limited version of bass redirection called "Simplified bass

redirection". In this case, high-pass filters are not applied to the front channels, so their response

curves are flat and the bass from the front channels is not redirected to the subwoofer.

Method

Turn the Subwoofer ON, and set speakers to "small" where possible.

This method uses a sensed sweep from 20Hz to 20kHz to plot frequency responses for each of the

channels. For Test 1, the low frequencies are removed from the main channels and redirected to the

Sub: