Has Anyone Ever Run TWO Identical Pairs of Speakers ?

I have two sets of speakers and the sound is superb. Key, IMHO, is that the speakers be of the same manufacturer as mine are Martin-Logan Motion 40's coupled with the 35XTi bookshelf speakers.  The 35's are on stands and are same height as 40's. I use two amplifiers. An NAD C 375BEE and a Parasound 2125 v2. 

There is no phase delay or issue with the sound that I have read others in this forum to fear. The reason I did it was because my basement listening room is large and two speakers with one amp did not fill the room out with sound. I also have a listening couch and a Bar in the same room, so I can point the speakers to where I want the sound to be most pleasing. It is my belief that if speaker manufacturers wanted to make the BEST speaker they ever made - without constraints - they would make two speakers that reacted as one. IMHO, the sound stage, imaging, clarity, etc. - everything sounds better when you have additional drivers and more power. 

Very bad idea. First of all you will only get an additional 3 dB out of it. Worse, you will permanently damage whatever imaging you have. You can split up woofers that way because the wavelengths they operate at are very long but, you can not do that with midranges and tweeters. At shorter wavelengths the speakers start speaking in two voices instead of one. Tweeters have to be no farther than 1/2 inch apart to speak in one voice up to 20 kHz. When you move them apart like you plan on doing you are listening to a choir instead of a single voice and you smear the image and detail.

Imaging is far better with four speakers than two. If your speakers are using identical technology (martin logan uses ribbon tweeters and both pair of speakers I use are of same impedence and sensitivity - 4 ohm and 92 db) then you are simply adding more speakers without disturbing the manufacturers musical aim/result. It is akin to setting up a for a concert with the need for more speakers and more power to push them because you have the space that will allow for it. You should be cautious about placing two differing  mfg amplifiers in the same system. I researched and found that the NAD 275BEE and the Parasound 2125 vs are pretty close to being identical in nature, especially in output. The Parasound is great for the 35XTi bookshelfs because it comes with a filter that I use to negate any frequency of 40Hz or lower from getting to the bookshelfs as the 35XTi's only go down to 50Hz. All of my speakers are bi-wired with AudioQuest 5 wire.

So, yes, mixing various brands of speakers together with different amps and wires and whatnot, will likely degrade the sound. But if you pay attention to specification detail and only mix like sounding manufacturers, the result will not have any of the negative issues others have brought up in this thread. 

Even with the same brand speakers, you are wrong. I agree with mijostyn on this one, and we don't agree on much. You REALLY need to A/B these configurations with a switch and dB meter. Trust me, you will not go back to multiple drivers spaced apart. It's so much clearer with only one set!

There is zero issues with the sound being lucid. You can hear all the instruments and distinguish them from one another. There is no muddiness or thing that makes you go ..mmm.

Not sure why I would need a dB meter. Both amps are 150 Watts per channel and both amps have gain levels (both L & R) to match the sound level with other amps in your system. 

With that being said, my bookshelf speakers sit approximately 3 feet behind the tower speakers. The Parasound is a bit brighter than the NAD, and that was not an accident. The NAD amp on it's own is a laid back amp, but the Parasound, with the 35Xti's, provides liveliness and excitement. 

It is easy to listen to one pair, then the other pair, and then both pairs together. If you were like everyone else, it is a no-brainer. Four speakers is "clearly" better than two. 

All I can definitely say is to my ears, a single pair of the F328Be’s are better than a single pair of the RT-2000p’s, but a DOUBLE pair of the RT-2000p’s are significantly better than a single pair of F328Be’s. When I run the math, $20,500 vs. $450 plus another $100 for an extra Polk CS-400 centre channel, it’s a no brained even a cave-man could figure out.

Stereo is defined as a sound directed from two or more speakers that seems to surround the listener and to come from more than one source; stereophonic sound. 

However, if you are a baby-boomer -  and I would say with fair certainty that many audiophile products are aimed at this demographic - then two speakers hooked up to one amplifier is, and has been, the status quo. 

Surround sound, believe it or not, was incorporated into the movie soundtrack "Tommy" in 1976. That was the beginning of what we all now know as five channel surround sound. However, as we all know, 5.1 did not make it to living rooms until mid-1990's at best. Personally, I did not have a 5.1 system until 2005.

My two amp; four speaker setup has nothing to do with 5.1 as I have a separate setup for TV watching. But many self described audiophiles use the two fronts for stereo if the amp allows for it. Quite plausible nowadays to not have two systems as the costs can be exorbitant. 

Speaker manufactures have generally stuck to the selling of two speakers due to the history of stereo, but by doing this, they do a disservice to those that have large listening rooms or simply have a want to fill a room with more sound than two speakers can provide. There is scant articles written about this for a reason, no manufacturer wants to sell you four speakers - they want to sell you two. Yes, there is an argument that relates to the loss of symmetry and the room acoustics become much more intertwined with the success of keeping the sound "as if it is coming from one source". But that is all part of the fun, IMHO. 

Every speaker manufacturer stair steps their product line. You generally have between 3-6 offerings, each stepped up in price. If a speaker manufacturer offers a specific technology (say ribbon tweeters) in their base product, and their top of the line speaker offers the same technology (most do), then it goes without saying that you may very well be better off buying four base speakers instead of two top of the line speakers from that manufacturer. In every case, you will spend less money to fill out sound in a large room. 

As it is, my two amplifiers each allow for 4 speaker hookup (4 speaker binder posts). Meaning, I could add four more speakers without adding anymore amplifiers. 8 speaker stereo - now that is unheard of!! - but one that the amplifier manufactures seem to have no issue with.

Thank you for this thread, vinyl_rules. Apparently, there are not many of us. I would never go back to two speakers and everyone who has listened along with me can attest to the sound of four vs. two in my system setup. If it sounds like a concert, and I am sitting front row, then my efforts are rewarded on a daily basis because I took a chance that no one else seems to understand. But you do! Good luck!

Now I have a problem: They sound so good that I guess I now need yet another pair for parts/backup!

Vinyl_rules - That is funny. Like me, I assume you are analytical and when a plan comes together, you worry about ensuring that the plan can thrive for a lifetime. Too good to lose! All your efforts will be lost without that crossover! lol :)

Similarly, when I built my bar in my basement some 10+ years ago, I found that the space between my cabinets - behind the bar - was perfect for a 37-inch TV. In 2010, 37-inch TV's were widely available. Over the scant years since then, I became worried that once my 37-inch kicked the bucket, I would not have a suitably-sized TV to fit in that space and so what should I do? Worry on a daily basis, or take the appropriate action to reduce my stress?

Of course, I went on craigslist and drove long distances to subsequently purchased 3 more 37-inch TV's. I think I have all of the great 1080p, 37-inch TV's from the 2010 era! - the Samsung red touch and the superior Panasonic TV's, of which I have two slightly different models. In any case, this led to alarm from my wife as I seemingly was on a mission to ensure I had cornered the 37-inch TV market many years later - after it's peak! She was mystified; I was feeling smug. 

Fast forward to a couple years ago when I realized that there were 40-inch TV's - that I believe they still make today - that would fit in that space due to the reduced bevel size around the TV, making a 40-inch real close to the size of bygone era 37-inch TV. That made me feel a bit ashamed that I did not see that coming, or that I have 3 TV's in storage that will likely never see that light of day.

That experience has pretty much stopped me from meddling in my own affairs. It provided me with a focus on enjoying what I put together and listening without a compelling voice in my head saying things like, "I wonder what it would sound like if...". I have found, for the time being, peace! lol :)