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Is the 2.5 way speaker the ideal home speaker?

Time for what I hope is another fun thread. 

One type of speaker which is actually pretty common but which gets little press / attention here on audiogon is the 2.5 way. 

A 2.5 way speaker is almost a 3-way, but it isn't. It is a speaker with 3 drivers, but instead of a tweeter, midrange and woofer (TMW) it lacks a true midrange. The "midrange" is really a mid-woofer, that shares bass duties with the woofer. Often these two drivers are identical, though in the Focal Profile 918 the midwoofer and woofer were actually different drivers with the same nominal diameter (6"). 

The Monitor Audio 200 is a current example of the concept, but I am sure there are many others. It's also quite popular in kit form. One of the most high-end kits I know of is the Ophelia based on a ScanSpeak Be tweeter and 6" Revelator mid-woofers. I haven't heard them, but I am in eternal love with those mid-woofers. I believe the original plans come from the German speaker building magazine Klan Ton. 

However many other kits are also available

But regardless of kit, or store purchased, are you a 2.5 way fan? Why or why not? 

Best,


Erik 
erik_squires
erik_squires OP
16,714 posts
 
Let me get a little more basic. Typically when you read about a "crossover point" in a speaker, you are actually talking about 2 filters:

A low pass
A high pass

So a 2-way speaker has a crossover point of 3 kHz. That means there’s a high pass filter that goes to the tweeter tuned to 3 kHz, and a low pass filter that goes to the mid-woofer that is also tuned to 3 kHz. I should point out that reality is even messier than this, but let's stay away from that.

A 3-way speaker has 2 crossover points (say 300 Hz and 3kHz) and 4 filter sections.

1 - HP to the tweeter
2 - HP and LP to the midrange
1 - LP to the woofer.

This adds up to 4 sections.

A 2.5 way also has 2 crossover points, but is missing 1 filter section:

1 - HP to the tweeter
1 - LP to the upper woofer
1 - LP to the lower woofer

That missing HP filter allows the upper woofer to play all the bass.
kijanki's avatar
kijanki
4,452 posts
 
It is Beaming and not Banding - sorry.  Please read "Speaker horizontal directivity" in the link I provided.
twoleftears's avatar
twoleftears
5,320 posts
 

Skeptical: 3 drivers are cheaper than 4.

Positive: only dealing with 2 different makes/models of driver, easier to integrate overall sound; no double "hand-off" from the mid-range.

erik_squires OP
16,714 posts
 
Hi Kijanki!

You say beaming is a disadvantage? I disagree! :)  A speaker with tight dispersion can sound better in the sweet spot, especially with an acoustically messy room. 

It all depends on your listening style and location. 

Some of Magico's smaller speakers are very wide dispersion. Great stereo imaging no matter where, but the trade off is they need a lot of room or great room acoustics. 

Best,


E

cedargrover
302 posts
 
Hi Erik,

Are there challenges in designing a crossover for a 2.5 way given that a large portion of the frequency range (bass) is shared by two identical drivers, but another large portion (midrange) is handled by just one driver?  I was thinking in terms of level matching due to that transition from two drivers to one driver.  

Thanks!
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