Surrounds too different from fronts?

[nm2285]

Well I've been enjoying a 2.1 config for years and finally decided that I'm going to upgrade to surround sound. However, I'm going to do it cheaply.

My mains are my design and use the Peerless 850122 6.5" driver and the Vifa XT19 ring radiating tweeter:
http://www.d-s-t.com/link/peerless/data/850122.htm
http://www.tymphany.com/datasheet/printview.php?id=111

I'm going to build another speaker for the center channel out of those two drivers. Then for the surrounds, I'm planning on 3 boxes on the walls (for a 6.1 setup) with only 1 of these in each:
http://www.timn8er.com/Aurasound%20NS3.htm

It's a well reviewd driver and for surround duty (which mostly will be used for movies, very little for music) I think it will work nicely. The beauty of it is that I probably don't need any kind of crossover in it. It's about as simple and cheap as it gets.

Anyone see any problems with using a design so drastically different for the surrounds assuming multi-channel music wont be a huge deal?

[MrPorterhouse]

The fact that its drastically different from your front soundstage isn't such a concern, but what is a concern is the response of your surrounds. While its true that surrounds don't carry a lot of impact, and its also true that you can set your crossover to 100Hz to help, you still can't get away from some of today's agressive surround sound tracks. There are some movies that demand a quality speaker, or at least in order to take full advantage of the surround experience, you'll appreciate a full surround speaker.

I don't know how that driver will extend when put in a box, so if you can get extension down to 65Hz, then you'll be good to go. Even if you select a 100Hz crossover, then frequencies at and below the crossover will still be called upon by that speaker, and the more capable your speaker is, the more natural the rolloff and easier to blend. Considering the capability of your mains, you might want some capable surrounds as well.

[JCD]

My $0.02.. will it make a difference? Yep. Consider scenes where a plane/spaceship pans from the back to the front. That transition is not going to be exactly seamless.

Is it the end of the world? no. And for the cost of the driver's you're looking at (as well as the terminal cup, plywood, etc), I'd give it a try.

An alternative I've found (but haven't tried/heard) is from Zaph. It does have a crossover though, but seems to be pretty minimal.

JCD

[nm2285]

Thanks for the replies. Yeah I understand about the lower frequencies being missing. I'm hoping maybe they'll extend to 80hz or so (I havent worked it out yet) and I think that would be acceptable.

Seemless? sure as wont be, but I would need a significantly large surround speaker to match with my fronts. i have neither the space nor money for that.

i've seen the design by zaph and read on diyaudio forums that some people prefer the NS3 driver. Its about double the cost, but theres no need for a crossover so its a good trade-off.

[JCD]

I can't wait to see how they turn out.

I love projects like this -- fairly simple, fairly inexpensive, potentially great results.

Sometime when I have time ( ) I want to get more serious about learning the details about speaker design instead of the generalalities that I've got now.

JCD

[nm2285]

Unfortunately I probably won't get started on them for quite some time (don't have the tools at school!), but of course i have to plan ahead.

I was thinking about venting the box to get a little more lows out of it. Any idea if that will affect the performance of the higher frequencies?