Axiom Home Page Forums General Discussion Home Theater QS8's and M2i's arrived!

My QS8's and M2i's arrived today!

I've got the QS8's mounted (VERY easy, thanks for the tips guys!)

Wow! MUCH better than my old Polk LS f/x surrounds! Not only do I hear more effects, the sound is much fuller. Sweet!

The M2i's are much bigger than I was imagining! I can't wait to get them hooked up, but I'm still waiting for my speaker cable to arrive. (I ordered 100' of 13ga white speaker cable from Accessories4Less)

Yeah!!!! My 7.1 system is FINISHED! (now just need a TV/FP and a new DVD player!)

Are the M2 visually bigger than the QS8. Still a toss up for me for 4 x M2 or 2 x QS8?

thx for any info

Craig, while you're waiting for the back surround cable hook up the M2s as mains and let us know if they blow away the M60s.

They're about the same size. The M2i's are taller, yet the QS8's are a bit wider. The QS8's seem heavier too.

is there a lot of material available in 7.1?....ron

Ron - there actually is no such thing as "7.1" since the back channel is mono which is really "6.1". What vendors have done is give you the capability to have two back channels instead of one to spread the effect over a larger area if your room demands it. I have a 7 channel amp, but only use a single back channel due to my room layout, but it works just fine (plus one less channel to drive).

To answer your original question, I believe the software for 6.1 really got kicked off with the Star Wars I which has a Dolby Digital EX track (matrixed). DTS also has 6.1 which can be either matrixed or discrete and I believe is called DTS ES. In any case, more and more titles seem to be coming out with 6.1 and there are several available today.

The way the matrixed version works is just like Pro Logic - in other words the center channel info is encoded (or simulated) using the info on the surround channels, just like it does for the center front off the front left and right. The DTS ES discrete channel is a separate channel and is consistent with the DTS philosophy of using discrete channels.

Some equipment allows you to auto-decode (if the flag is set correctly on the DVD), turn it on all the time, or shut it off. Auto-decode works fine if the proper flag is set on the DVD - which some DD EX titles do not implement correctly based upon problems with some equipment in the early days - doesn't appear to have been an issue with DTS ES however. Some folks turn it on and leave it on all the time as again, it works the same as pro logic in the fronts and will light up the back channels from info on the surrounds.

My experience has been that in most cases, you can tell the difference with 6.1 material, especially if the sound engineers worked to put meaningful info on the channel. Also, depending on your room size (and available DSP modes on your preamp), it can fill the room more with effects. I personally only use it when there is specific 6.1 material - e.g. set it to auto decode but have to invoke it manually on DVDs with the DD EX flag not set correctly.

Cheers,

Doug

What is the current consensus regarding the benefits of having two back surround channels versus just one?

This puzzles me-- I've got an H/K AVR-525, and it has 7.1 analog inputs, and discreet amps for the back surrounds. This would indicate to me that some "true" 7.1 (maybe not yet, I suppose) is/should be available. Does Logic 7 provide for this, or is that a matrixing thingie?

I think it's just a future-proofing feature.

Yep, I've got the 525 too, the 7.1 is future proofing, though the internal decoders won't support what ever the future may hold. You can run in virtual 7.1 which will send the same rear center output of 6.1 into two rear speakers.

Logic7 is a matrixing thingie. 2 channel to 7 I believe

I remember seeing a big long-winded post by somebody on AVS or HT forum describing the science of it. He may have been blowing hot air, but he did say that studies have been done (though they were older - back to the to the 70/80s) that concluded that ears don't process sound the same way from the rear as they do from the front (that evolution thing). According to the 'experts' 2 rear speakers (spread apart a bit) created a more effective sound field. At least that is an extremely condensed version, and I don't recall the exact argument for it. So take it for what it's worth.

I would assume one of the reasons for discrete amps for the back surrounds is to allow for calibrating the speaker level based upon where it is positioned in the room. Otherwise, you could theoretically run two speakers off the same back surround channel.

Even though I only use one of the two available on my AVR, both have individual speaker gain adjustments to allow for room dynamics and weird speaker placements. If I had a wider room I'd probably get another QS8 and go for it just to impress my friends :-) However having two speakers about 2 feet apart wouldn't seem to provide any additional soundstage for the back at this time - so one is fine for now...

Cheers,

Doug

Scott's(sidvicious)recollection is about right. For some strange psychoacoustic reason, it's been shown that on some occasions when only a single rear center surround speaker is used, a "reversal" occurs in which a sound that should be directly in back appears to come from directly in front. Using two separated back surrounds avoids this possibility.

Ken, the 7th amp isn't really just for future-proofing. For example, on your 525 you can program the 6th and 7th amps to power speakers in another room instead of back surrounds. Also, although a 6th amp can be used to power two back surround speakers(there's no "real" 7th channel involved, and except for some special processors the 7th speaker gets the same signal as the 6th), using the 7th amp makes for an easier load, especially if the two back surrounds would be low impedance speakers being driven in parallel by the 6th amp.