Two way vs. Three way Speakers


In terms of sound what are the differences good and bad between two way and three way speakers. I have been researching and collecting information about a diy speaker project - for example looking at the SEAS Thor design (three way) vs something like the Proac 2.5 clone which is a two way. Still reading about other options too. Best speaker I ever owned was Maggies through the 80's that sadly were not child friendly. Currently have 2 way - Paradigm monitor. Looking for accuracy, detail, clean sound (great mids and highs)that is true to recordings - for cds through modded Jolida (warmer) and MF amp. Thanks for any discussion and thoughts on this.
ladavid
Midrange is no problem for two ways , it is bass. If you have a small room or listen to music that doesn't need to be played very loudly then two way is ideal. Three way can play louder with more bass but the midrange can suffer by being divided between two drivers. For large rooms or high DB's three way is better , but is inherently harder to design properly and more expensive. Subwoofers can give 2 ways the bass of three ways and are a good compromise. All the above is , of course , speaking in general terms. Each speaker has it's own virtues and faults.

A simple 2-way with really good drivers and crossover put in a properly designed box can be absolutely stellar.  As stanwal menionted, you're most likely to give up deep bass from a good 2-way, because anything larger than an 8" woofer tends to cause other issues.  Bass output is relative to the room, and can always be augmented by a subwoofer (or two). 

A 2-way is simpler to design, and less costly to buy good parts for, so when shopping at a price point that's worth keeping in mind, but it really depends on what you're preferences are and what the specific speakers are.  I'd personally rather buy a well made smaller 2-way to get stellar mids and highs, then add a sub if necessary, than to give up that critical clarity permanently just so I get more bass output from a larger 3-way.  Just my preference. 

Like virtually any engineered product, there are an endless series of tradeoff decisions to make when designing a speaker and deciding on 2-way versus 3-way (or more!)  As others have noted, transitioning from one driver to another affects the sound quality in that frequency range.  The ear is particularly sensitive in the bandwidth in which most instruments (including voice) have their fundamental range -- roughly just under 100 Hz up to about 3,500 Hz. Some speaker manufacturers try to avoid switching drivers in this range.  However, if you try to use a large driver (to preserve bass) you'll end up with beaming in the upper range of this band. Using a smaller driver addresses this issue, but makes bass response more difficult. 

And these trade-offs go on and on in lots of other areas. Ultimately, all you can do is audition lots of speakers and see which make and model best lines up with your own preferences. 

Or, you could do what I did and end up with a set of Ohms. They use one driver for bass up to around 8 kHz and only cross over to a tweeter at that frequency. But, they have their own compromises since they have a semi-omni radiation pattern, which some love and others don't.  

So, the advice you get here may give you some interesting candidates to check out but ultimately you should ignore the rigid advice others give and just buy what sounds good to you. 

I have three systems. One has two-way speakers. The other two have three-way speakers. They all sound good.