Logic 7

[Ed Kreamer]

Esteemed Colleagues:

I currently use an H/K AVR 354 as my main system. As most are aware, the unit features Dolby PL II, DTS Axis 6, and Logic 7 processing, as well as AV processing and 2 channel. I've had the unit about 6 years now and like it very much. When listening to CD's in multichannel I've noticed that the Logic 7 seems to alter the spectral balance of the recording. (note; I listen mainly to orchestral classical music ) When using the Dolby PLx II, there is no change in timbral accuracy, at least as far as far as my aged hearing will allow. I've compared both to 2 channel and found this to be the case, that PLx II is closer to the sound of 2 channel. Has anyone here found this to be the case as well? I wonder if my receiver is malfunctioning and unfortunately no one in the Puget Sound region seems to carry H/K stuff, so that I can compare.

[Don C]

I think that Pro logic limits encoding and decoding of the rear channels to 7Khz or less. So if the changes you hear are above that frequency maybe that explains it.

[hsosdrum]

I've noticed the same thing with my Lexicon DC1, so I would say that it is not being caused by a malfunction of your HK receiver. The spectral balance seems altered throughout the frequency spectrum on all recordings when compared with the stereo mode, but I notice the largest difference from around 150Hz on down. I'm guessing that the Logic 7 circuit and attendant multi-channel presentation seem to remove a lot of the inter-channel phase cancellations that are typical in two-channel reproduction, probably due to their altering (or eliminating) some of the comb filtering that's inevitable when you stuff a bunch of different sounds through just two speakers.

I base the preceding conclusion on the fact that with the recordings I make of my own drums in my own studio (a total of nine microphone feeds), from around 100Hz on up the recording's spectral balance when played through Logic 7 sounds much closer to the instrument's actual spectral balance than it does when the same recording is played on the same system through two-channel stereo. (And if I turn my subwoofer down about 8dB from its normal level the balance is closer all the way down to around 30Hz in Logic 7 than it is in stereo.) The spectral balance just plain sounds more "right" in Logic 7 than in stereo. I can't speak to whether or not the difference in spatial presentation is more accurate in Logic 7 because I never get to hear how my drums sound from the listener's perspective (since I'm always the one playing them). Logic 7 does a more accurate job of recreating the player's perspective than plain stereo does, but in my recordings I'm trying to achieve more of a listener's perspective than a player's perspective. (BTW, my recordings seem to succeed pretty well in presenting the listener's perspective when played in stereo on many different systems, I'm happy to say.)

Of course, you're free to listen in whatever mode sounds best to you—there's no absolute right or wrong, only what you like best. I do all my listening in Logic 7 since I much prefer its multi-channel presentation to plain-Jane 2-channel stereo.

YMMV.

[BMWCCA]

In the cars we sell with Logic7, the only change is to basically create a surround effect. Makes the news broadcasts sound like they're coming from the bottom of a trash-can and gives the music a little sensation of larger room size.