5.1 or 7.1 in Hometheater..
 

Actually 7.2, (I have 2 JL F113 subs and an AVR and Amp that can handle the added speakers.)

My theater is 80% Movies, anyone have an opinion if I should move to 7.2 from 5.2, even though most sound tracks are 5.1 lossless?

My primary front row is in the precise spot for 5.1 now, so should I add side speakers for improvement?

Is there improvement??

Thanks.

There is a definite improvement when done right; but you already knew I would say that. ;)

The Dolby production definition for the LFE channel is 10dB of headroom, 3Hz-120Hz, above 5 large full range directional loudspeakers. Adding multiple properly sited subs lowers the noise floor and lowers distortion in the bass. But there is only 1 LFE channel in production, defined as the .1 channel. Regardless of number of subs, the system is .1. 2 LFE subs in the system is still 5.1 with 2 subs.

There are multiple ways to fill the sound field in a theatre. Depending on size or room and location of seating, there is no reason do do anything beyond 5.1. As you correctly pointed out, mastering is done in 5.1.

Going to 7 speakers can help to solve room size/shape issues. However in many instances, doing 5.1 with 7 speakers is more effective than 7.1. In that case speaker placement is quite critical but the rewards are worth the effort. This virtual 5.1 is sometimes used on mastering stages as well.

Should you add 2 more speakers? Depends on the room. So too does the placement of the speakers.

agee with metaphacts- i prefer 5 channels propely done. Only 7 channels in a really big room with multiple locations to help "fill it in".

I went to 7 channels only because I had extra speakers and extra amp blades. I noticed not one whit of improvement. :(

Theater set up is highly misunderstood. For ideal set up guidance one should read the Dolby Production Standards as well as make yourself familiar with the International Telecommunications Union (ITU)-R BS 775 protocol.

Then you need to pay as much attention to center and surround placement as you do fronts.

Certainly the system had to sound different after adding 2 speakers and reconfiguring surround channels, delays, and gains. Any preferences?

Bill, it may be a testimony to how crappy I set it up with 5.1, but honestly, it is barely different, if at all. Just a very little ambient sound from the rears. Like I said, I did it as a lark since I had the gear. Mind you, I think it sounds good, just not better than what I had.

I didn't have room for two speakers on my back wall due to configuration so I did a 6.1 setup with WS350 in-walls for my 3 surround speakers. I honestly don't think it is much if any improvement over standard 5.1, and given that most multi-channel music and the majority of the uncompressed blu-ray soundtracks are 5.1 anyway I would recommend focusing on optimizing your 5.1 sound over doing 7.1 unless you have a very large room. Great 5.1 > marginal 7.1 IMO.

What does 7.1 do to 5.1 sacd music. Rear speakers silent??
Sides only?

When I was running SACD mine played the side surrounds and the rears were silent.