CDWG and Qsound question

BrunoB · « **on:** 12 Jan 2006, 12:24 pm »

I wonder how a speaker with a CDWG would reproduce Qsound effects such as in Roger Water's "Amused to Death"? Would it be stronger, would it be more stable regarding the listening position, .... ? Or may it would not be different from a non-CDWG setup.

Thanks,

Bruno

John Casler · « **Reply #1 on:** 12 Jan 2006, 03:51 pm »

Quote from: BrunoB

I wonder how a speaker with a CDWG would reproduce Qsound effects such as in Roger Water's "Amused to Death"? Would it be stronger, would it be more stable regarding the listening position, .... ? Or may it would not be different from a non-CDWG setup.

Thanks,

Bruno

Hi Bruno,

I tried it at the SHOW. I have a cut from Amused to Death on my reference cd.

Q-sound requires equal amplitude from both channels so the CDWG does not carry over much better, but it "IS" better than non-CDWG, but localization is just not as precise when you move out of sweet spot.

Bob Wilcox · « **Reply #2 on:** 13 Jan 2006, 01:50 am »

I find the localization of the effects in the sweet spot better than with the stock RM-40s. Very noticable tracks 1 and 8.

My room is fairly small. My listening position has a single recliner so there is not much lateral room in which to move around. It is also not tricked out like John's.

Bob

BrunoB · « **Reply #3 on:** 13 Jan 2006, 08:44 am »

John and Bob,

thank you for your input.

It is nice to read that the Qsound effect still works (and is better) with the CDWG. Up to now, the best effect I have heard is from Apogee Divas (line source). A not so good one was with a pair of B&W 802D's (may be the distance between the speakers was too high). One of my goal is to understand what factors are important for Q sound reproduction both on the speaker side and system setup (speaker positions, room acoustics).

Bruno

CornellAlum · « **Reply #4 on:** 13 Jan 2006, 02:16 pm »

Could someone explain to me or post a link that describes what Q sound is. I haven't the vaguest idea what you guys are talking about but I would like to try to understand.

D~

hoosier21 · « **Reply #5 on:** 13 Jan 2006, 02:32 pm »

http://www.qsound.com/2002/technology/main2.asp

very COOL stuff,

csero · « **Reply #6 on:** 13 Jan 2006, 03:05 pm »

Qsound is a transaural encoding, based on crosstalk cancellation. The problems in Qsound are:

-they use XTC on the recording side, not on the reproduction side, this way they encode the filter response in the record. An XTC filter can sound strange outside the intended sweetspot - as NYravers could hear it last year. This leads to the other problem...

-Qsound XTC filters calculated for the 60 deg point source stereo triangle. This is the worst possible XTC setup, as the filter can work efectively in the 700-2k range only, and even in this range the sweetspot is very small and very sensitive to speaker positioning, head position and individual HRTF differences. This is the reason it is used only for individual short therm or moving source effects only.

- XTC assume that the primary sound from the speakers are much louder than the room reflections or diffractions from the cabinets. Wide dispersion or strong edge diffractions reduce the effect further. Line sources, while reduce floor and ceiling bounce, somewhat wash the effect with multiple arrivals.

- off axis response of an XTC speaker pair is very different from the sweet spot response so wide dispersion or live room is not desirable.

ctviggen · « **Reply #7 on:** 13 Jan 2006, 04:11 pm »

How do you know all this stuff?

csero · « **Reply #8 on:** 13 Jan 2006, 04:36 pm »

I'm knee deep in various transaural methods and DSPs.

ctviggen · « **Reply #9 on:** 13 Jan 2006, 04:44 pm »

Ah, I see.