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Old 29th August 2008, 03:59 PM   #11
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rabbitz

Thanks again for chiming in.

The general topic (not thought and stated clearly up front) is if your amp is capable of 7.1, how many speakers should you sensibly use?

Better (best) clarity is also my aim.
I’m also skipping the centre.

Is the 4.1 you settled on:

Front L R
Back L R

Or

Front L R
Side L R

Ie what angle are the back two from you, the listener?

Also, how close tonally need the back or side speakers be to the front?

(do you have a link or post the reflects your current views?)
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Old 29th August 2008, 04:22 PM   #12
rabbitz is offline rabbitz  Australia
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otto88

Unfortunately I have a wall directly behind the viewing area and an awkward side wall arrangement which limits the rear speakers that can be used.

I place a priority on atmoshere from rear speakers more than direct sound so needed an arrangement that would hide the location of the speakers.... a sort of pseudo null as they are hidden by the sofa.... to create a more diffused pattern.

The end result was side firing with a slight tilt backwards. The centre rear when it was there fired up to the ceiling. Most of the sound I hear is reflected sound but is still able to provide location and steering when required. See the pic even though the quality of the shot is not real good. You never know they are there so very SAF. A lot have had great success with rears that fire upwards.

I had a visitor from Tassy who has never heard a HT system (or has hardly ever been to the movies from the reaction). I played the scene from Top Gun after the flameout when the F-14 goes into a flat spin. The steering and effect was very real and she freaked out... mission accomplished.

It's hard to say what works best as each room, furnishings are different but you just have to experiment. I think if you use side LR then I think the rear LR are required.

I needed clear dialogue as my hearing is not as good as what it was especially when other action is happening, good soundstage LR and front to back, good steering and atmoshere and the final result is very good and satisfying with 4.1.

I've read a big mistake is to have the front LR too far apart as they should be next to the screen to be convincing as the soundstage has to lock to the screen.

BTW... Kendal has finished your speaker but has lost your phone number so he can't let your know.
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Old 29th August 2008, 04:37 PM   #13
rabbitz is offline rabbitz  Australia
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The 4.1 is
front LR
rear LR
with sub out of sight and fires sideways into a wall

I was joking about the topic as I got lost rambling on.

I think it's important to use the same mid-woofer or similar throughout. The fronts of course are the most important and I would use at least the same brand / type for the rears (for say 300Hz - 3kHz) but can be much smaller as these are normally set to small. All my 4 are set to small and I let the sub handle the LFE channel.

The speakers in the pic next the the screen are the front LR and are only 5" 2-ways.... SEAS 27TTFC / Peerless 850488.... plenty of go, clear, good dialogue and only handle from 90Hz up.

You can see the angle of the rears in previous post and as I can't see them from the seated position, I can't locate them acoustically as well.

One other thing.... I only have to cater for an audience of 2 (plus 1 dog) so it makes it very easy as there is no off-axis. As soon as off-axis comes into it, it's a whole new game.
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Old 30th August 2008, 04:25 AM   #14
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rabbitz

You’ve confirmed my loose hunches:

> atmosphere from rear speakers
> as each room, furnishings are different but you just have to experiment.
> I think if you use side LR then I think the rear LR are required
> you never know they are there so very SAF
> my hearing is not as good as what it was especially when other action is happening
ditto

and one thing I hadn’t thought of, which its better to know about up front:
> a big mistake is to have the front LR too far apart

(Thanks very much for the news re Kendal too!)
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Old 30th August 2008, 04:39 AM   #15
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rabbitz

this surprised me

> it's important to use the same mid-woofer or similar throughout.

As clear dialogue is more important to me than general action/ background, and intelligibility is most concentrated in the range 2 – 4 Khz, I’d guessed that it's much more important to use the same *tweeters throughout.

I have two pairs of the same tweeters, but none of the same mid-woofers. (And my (2nd hand or bought on special) mid-woofers are too $$ to get extras) so thought matching the fronts and sides tweeters would give “enough” matching.
. . .
Though the front intended mid-woofers are mag cone, and the intended sides metal cones, maybe that’s close enough . .

> The fronts of course are the most important, and I would use at least the same brand / type for the rears (for say 300 Hz – 3 kHz) but can be much smaller as these are normally set to small.

I thought if the rear channel(s) are mostly effects, matching there is much less important than matching fronts and sides – no?

> I only have to cater for an audience of 2 (plus 1 dog) so it makes it very easy as there is no off-axis. As soon as off-axis comes into it, it's a whole new game.

Lucky you, my tribe can get big, but that’s another issue

Cheers
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Old 30th August 2008, 05:19 AM   #16
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In the Loudspeaker Design Cookbook, there is a HT speaker design and he's used the same mid-woofer throughout but uses different tweeters on the rears due to the cost and comments that they are of similar type so the timbre would be similar. There's also a good section on HT speakers in general and dedicates a lot time to rear speakers.

The point is, when a sound starts at the front as a "WOOOOSH" you don't want it to turn into "wiiiish" when it hits the back speakers. I think the majority of the energy would be coming from the mid-woofer rather that the tweeter. As long as the mid-woofer has a similar tonal sound, close enough as it's HT after all and not stereo music. At one point I had some Vifa TC mid-woofers at the back and tonally worked quite fine with the Peerless on the fronts. The rears do not have the priority of the fronts and are along for the ride only.

Important to lock the sound to the screen as you don't want a car screeching to a halt at the left side of the screen having the sound coming from 1m to the left. It's very impressive on demos with a wide soundstage but not very convincing. A woman talking with a 3m wide mouth is not appealing.

Have a look at the THX spec and work backwards. Also some good info on the Dolby site.

With a tribe.... that's easy. You grab the best spot (plus remote) and shout "Movie's about to start" and they can scramble. Kids don't give a rats about the sound as they are taken by the visuals.
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Old 30th August 2008, 08:12 AM   #17
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Lots of wisdom there

Cheers
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