User manual RANE HOME THX REV 1.5

[. . . ] 1. 5 Home THX® Audio System Room Equalization Manual Rev. 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] 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. Measure and analyze as described in Section 1. 4. 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. A smooth curve, without radical peaks or dips, is what is desired. 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. [. . . ] Adjust the level exception: a new musical score was commisso that the meter on the controller reads sioned to tie the entire piece together. 0 dB(reference level) when this signal is provides a short and complete movie going playing. experience, and shows off all of the potential of the Home THX Audio System. contains a Chapter 6: Pink Noise, Left & Right, In-Phase, wide variety of sounds, from very quiet passages, -10 dB; to loud, explosive ones; there are sounds panThis signal is comprised of broad band noise ning between Left and Right, and from front to and can be used to adjust the Center output level, back; there is soft dialog buried in the midst of or check the phase of the Left, Right, and Center competing, loud sound effects; there are power- speakers, as well as the Subwoofers. [. . . ]