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Discussion Starter · #1 ·
My home theater is 19ft * 13 ft, with two rows of seating. The first row is about 12 ft from the screen and the second row is about 17 ft. I'm runnig 5.1 audio now with a single pair of bi/di-poles on the side walls, but the plan is to add a second identical pair on the rear walls when I eventually move up to 7.1.


I had originally installed the surround speakers mid-way between the two rows of seats. However, having the surround speakers a little in front of youw as distracting when seated in the rear row. So I moved them back so that they are in line with the back row. This substantially improved the sound at the rear row.


My problem now is that if I optimise the surround level for the rear row the level is too low for viewers seated in the front row. I haven't measured the difference yet but I'm guessing it is about 3 db.


Basically what I'm thinking of doing is adding a second pair or speakers on the side wall, wired in parallel with the existing pair and placing them in-line with the front row. I'm pretty confident my power amp is up to the job as it puts out 250W per channel.


I think I'd get good sound at the front row in this configuration. However, viewers in the rear row will hear some of the surround still coming from in-front of them. Although the amplitude of this sound would be about 3db lower than that coming from the speakers in line with them.


Has anyone out there done something similar and did you find it worthwhile?


Many thanks


Kurt
 

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You can add four side surrounds, or use tripoles at the sides, or go with the 7.1 design.
 

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1) Wattage has nothing to do with whether an amp can handle a parallel load - you'll drop the resistance in half, so an 8 ohm speaker becomes a 4 ohm which most receivers won't drive, but most quality dedicated amps will. If you're running 4 ohm speakers, you'll be down to 2 ohms, which almost nothing will drive.


2) Are these direct speakers, dipoles, tripoles...?
 

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Discussion Starter · #4 ·
The surround speakers are the Velocity Surrounds made by Phase Technology. They can be configured to run in either a bi-polar or a di-polar configuration. Current'y I'm running them bi-polar.


The surround speakers are rated at 8ohms each. My amp is a dedicated power amp which I had custom built. I'll contact the designer and ask him if it will have any problem driving a 4 ohm load. I would be absolutely amazed if it had the slightest problem with it. Of course, I could always run them in series which would put a met 16 ohms load on the amp if that was a problem, given that I've got wattage to spare.


My idea is to have 2 pairs of these speakers for regular 5.1 duty and to add a third pair when I go to 7.1. Fortunately they're very economically priced so the extra cost is not much of an issue.


Kurt
 

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Kurt, I'm wondering why if you are considering adding two speakers now, why not just go to 7.1? Is it that your current receiver/processor is 5.1 only, no 6.1/7.1 capability? I've been through something similar, moving my side speakers rearward from their original position for better sound in the back row in my 5.1 configuration. A few weeks ago I installed two rear speakers and went to 7.1. What I found was that with the 7.1 configuration, it sounded better in the front row with the side speakers moved forward about 30 inches from where they were previously. With the rear speakers filling in more, it felt less enveloping in the front, like all the surround sounds were located behind the listener (which they were of course). Moving the sides up so they were just behind the front row improved things greatly. With the rear speakers active, it is much less noticable in the back row that the side surrounds are actually forward of the listening position. It's much better balanced now.


In a nutshell, what I'm saying is that you may find that with your rear speakers in place, you won't need two pairs of side surrounds to get a balanced and enveloping surround effect in both rows. If you can, I'd suggest trying that first.
 

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Discussion Starter · #6 ·
My existing pre-amp only does 5.1, not 7.1. I'm holding off upgrading it until such time as DVI/HMDI switching is available in a decently proced pre-amp. My guess is that it will be another couple of years before that upgrade takes place.


In addition, the vast majority of source material is still only in 5.1, although 7.1 is becoming more popular at least for new bloackbuster movies. As a result I figured that even when I moved to 7.1, my 5.1 issues would still remain.


Kurt
 

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PAP is correct. If your speakers are 4ohms and your power source is 8ohms, you'll probably fry your amp quickly if you run speakers in parallel. However, you could possibly run them in series, thus creating an 8ohm load. What happens is an 8ohm amp driving 4ohm speakers has twice the current passing through it. Heat builds and the amp is damaged or destroyed. There are receivers and amps that can handle a 4ohm load. For example, I have an HK7200 that can handle a 4ohm load.
 

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Quote:
Originally posted by ktoolsie


The surround speakers are rated at 8ohms each. My amp is a dedicated power amp which I had custom built. I'll contact the designer and ask him if it will have any problem driving a 4 ohm load.


Kurt
Hey Kurt;


Yeah, your power amp will have no problem with 4ohm. It sounds expensive, so I would contact the designer anyways to make sure all is clear. In the past I've run cheaper amps at about 3.5 ohm (in actuality) for years, most of the time with the volume cranked & had absolutely no problems.
 

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Quote:
Originally posted by ktoolsie


The surround speakers are rated at 8ohms each. My amp is a dedicated power amp which I had custom built. I'll contact the designer and ask him if it will have any problem driving a 4 ohm load. I would be absolutely amazed if it had the slightest problem with it. Of course, I could always run them in series which would put a met 16 ohms load on the amp if that was a problem, given that I've got wattage to spare.


Kurt
OK, I missed that post...It was late.
 

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Discussion Starter · #11 ·
My surrounds were pretty high about 3 feet above ear-level for the rear row and almost 4ft above ear-level for the front row.


When I moved them rearwards to be in line with the back row I dropped the height about 6 inches.


Kurt
 
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