User manual RANE HOME THX REV 1.5

[. . . ] 1. 5 This document is Copyright 1995 by Lucasfilm Ltd THX and Home THX are Registered Trademarks of Lucasfilm Ltd Dolby Stereo, Dolby Pro Logic, and Dolby AC-3 are trademarks of Dolby Laboratories Licensing Corporation 1 Home THX Equalization Manual Rev. 1. 5 Table of Contents Introduction and Background: Why Room Equalization?3 Test Equipment Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 The Home THX Equalizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] These position differences can cause frequencies common to all the speakers to arrive at different times at the listening position, and partially cancel or reinforce themselves. At this point use the Center Channel EQ to adjust the response at the splice. DO NOT use the Subwoofer EQ . 1. 10) Confirm Subwoofer Splice: Left and Right Channel Next, in the Stereo or Bypass mode play both the Left and Right Pink Noise from "Wow!"; Chapters 8 & 10. Adjust both the Left and Right Chan12 Home THX Equalization Manual Rev. 1. 5 nel splices to the Subwoofer channel by using your Left and Right Channel EQs. Remember, if the relative levels are off, use your Home THX Controller to adjust the levels. Use only the Left, Center, or Right EQ controls to adjust for uneven frequency response at the Subwoofer splice point. If a dip remains at the Subwoofer splice point even after drastic EQ, check for correct loudspeaker polarity. Subwoofers or LCR speakers connected out of phase can cause a "suck-out" at the crossover point. Subwoofers offset from the LCR plane by a large distance or multiple Subwoofers can do the same. If you are using a single Subwoofer and have a large offset, reverse the polarity of the Subwoofer signal. If multiple and offset Subwoofers are used, you should attempt to smooth the response by reversing the polarity of the Subwoofer furthest from the LCR speakers, or by repositioning the offset Subwoofer. 1. 11) LISTEN!When you have completed your room equalization, play the circulating pink noise from "Wow!" (Chapter 7). Each front channel, Left, Center, and Right, should tonally sound very similar within the listening area. If the circulating noise sounds very different, go back and re-measure any offending screen channel. The reference channel for any timbre comparison is the CENTER CHANNEL. Correct EQ with Subwoofer Splice 80 76 72 68 64 60 25 40 63 100 160 250 400 630 1000 1600 2500 4000 6300 10000 16000 dB SPL Frequency Hz Fig 7 Please Note: The above curve represents atypical room EQ. Since rooms vary greatlyyou should not expect every equalized room RTA to look like the above illustration. With difficult rooms, acceptable tolerances can be up to ±3 dB. Your system is now correctly equalized. 13 Home THX Equalization Manual Rev. 1. 5 SECTION 2: Room Analysis with a Conventional RTA This method of room analysis was written tomimic the spatial and temporal averaging of the R-2 THX Audio Analyzer. The procedures for choosing microphone positions and the techniques for equalization are identical with both types of instruments. 2. 1) Define The Listening Area: The first step in correctly equalizing a Home THX Audio System is to identify the listening area. The equalized response of the system will be averaged over this area to provide a balanced sound field for all listeners. [. . . ] It gives you The following table of contents outlines the varian appreciation of what you are missing when you ous chapters on the WOW!Side 1: Alignment Test Signals: Chapter 1: WOW!; This is a remarkable thematic montage of Chapter 5: Input Level Calibration Tone; various George Lucas films, with fast, tight editing This 1 kHz tone is recorded at 0 dB (Dolby to emphasize interest and excitement. All of the reference level), and can be used to calibrate the soundtracks are essentially unchanged with one input level of your THX controller. Adjust the level exception: a new musical score was commisso that the meter on the controller reads sioned to tie the entire piece together. [. . . ]