Purpose of using same speakers for surround?


So, I'm wondering why I've heard it is best to have 4 identical speakers for fronts and surrounds? Since the rear (or surround) speakers are only giving out a limited amount of information to fill in details, I see no real reason that any reasonably competent speaker that reproduces down to 80hz wouldn't be just as effective?

In my case, I have been using matched Mirages across the front, with a pair of Pardigms for the rear. I keep thinking about wanting to get another set of Mirages for the rear, but unless there would be some marked improvement, I don't see the point?

Your thoughts would be appreciated.
baxter178
Vicdamone,

I'll do a little research and try to find out what the bookshelf size speakers from that family were. Obviously the speakers are older and harder to find, but that can work out in a huge price discount too (small budget).

That (using M series bookshelf speakers) was my original plan, but one keeps reading about same speakers all around for best sound (yes that's hard with towers), hence my post.

I honestly love what I have, since moving a Proceed amp3 to a stereo setup and adding a Rotel 1077, the Mirages came alive, not in an obnoxious brighter way, just much more detailed and open which I didn't expect with the amp3 being a nice piece to start with. Then replacing an old Yamaha receiver (used as a pre) with an NAD T175, and holy &^(-... I've seen the light of day!

One thing I have learned from the knowledge of the people on this site, is that it isn't the name on the pieces, but how the pieces you have work together. After years of wanting and waiting, I'm pretty damned happy right now :)

Now, if I can tweak it up just a bit more for minimal cost, by matching the rears, and possibly going to 7.1 I'll be good for a while.
If there are any members that would share with me the appropriate model #'s in the "M" series I should be looking for, it would be helpful :)
Thanks
So I emailed Mirage and got this for a reply:

"The original and former Mirage M Series models would have been engineered and designed from the former Canadian based Audio Products International (API) group which ceased to exist in or around 2006. Klipsch Group, Inc. USA acquired Energy, Mirage, Athena brands including all remaining replacement parts and limited product data for some of the older models (I have included some of the older PDF copies of any information I could still find for the older M7si and MC-2 models. There is no specific manual available for the former MC-2)."
"I am very sorry we would not be able to make any further recommendations to accommodate the expansion of your system using these older model speakers."

They say they can not offer any recommendations for the older speakers... I know there are members that claim to have sold Mirage in the past, perhaps one of you could help me out with model #'s that would timbre match my fronts?

Thanks
There's lots to consider for balancing things out to maximize the "team effort", which is a system. The more you do RIGHT, the better chances you have of attaining a quality effort, and great results.
Sure, you can get buy, and probabaly be just fine doing mix match. And, yes, the rears arent' as critical to the peformance of the system, as what's happening up front...you absolutely MUST match the front 3 speakers to produce a believeable, coherent soundstage with unifor tonality there. And this is the bulk of your pressentation.
Heck, I use two speakers, and sometimes not even a sub to watch on my big screen/receiver setup these days. But then I'm a bit lazy with all of this right now, and don't really care so much. I know..sad isn't it.
Still, if you want to add another properly balanced ingreadient to your mix, and keep the quality level of the system up, and be ambitious about it, you really should get the matching speakers ALL AROUND in the system, to maintain coherence and integrity, and so your soundstage has the potential to be transparant, and so you can just dissapear into the sound, and the gear gets out of the way of the playback chain.
What often happens is people end up listening to a collection of "gear", with limited fidelity potential and realism to the perforance of the audio. It can just end up being sound coming from different directions...and not really great sound, at that.
Think of it as taking the time to carefully spice a dish your cooking. Yes, you can be happy with just "ball parking" it. But heck, why not just throw anything in there, if better quality can't be had matching everything in the first place? Cause you're just not gunna end up with anything SPECIAL from the sytem, otherwise. Nothign you can't get from a better home theater in a box effort, if you just throw it together, really.
Just some thoughts
Avgoround,

Considering that I am extremely happy with my front 3 speakers (and how they perform with my other equipment), I don't believe I would be throwing some "gear" together by going with bookshelf speakers for the rear, so long as they have the same drivers as the fronts. This would give me a timbre match, or am I wrong here?

If I am incorrect in this understanding, please let me know. I do not profess to being up to date or overly indulged in electronics... that's why I come here to ask you guys that are more involved.

Also remembering that on 12-17 I posted this comment:

"I can now see a definite merit for same speakers if I were listening to classical music via MCH SACD... I am not. Clearly this would be ideal for those that do."

Thus, I believe the bookshelf speakers from the "M" series with the same drivers would achieve my goal. If I am incorrect in my assumption here guys, again, please let me know!

So, unless I get responses informing me I am wrong, and need the larger M7si for the rear (considering my use), what I really need is someone that knows the Mirage "M" series well enough to recommend a suitable bookshelf speaker from that series, so I can begin my search.