Is the 2.5 way speaker the ideal home speaker?

Although I own 30 year old, 3 way Thiel 3 way speakers (CS2) and still enjoy them very much, when friends have asked me what speakers to buy in recent years, I recommended Spendor...the A5 (now discontinued) and the D7 (current).  Both are 2.5 way speakers and both owners love them.  I do too.  What’s not to love?

At the end of the day, it’s about what sounds good to you, regardless  of speaker design or price (assuming you can afford it?)

The Spendor’s also pair quite well with Linn and Naim gear, which my friends and I all own.  It’s a classic combination, which certainly make a difference, along with the room.

Erik, Few questions.

1. Isn’t crossing at 2kHz or lower in the range of female voice, that has fundamentals between 350Hz and 3kHz?

2. Isn’t crossing below 2kHz to close to resonance of most tweeters? I’ve read recommendation to keep crossover frequency at least 1-2 octaves above tweeter’s resonance.

3. Break-up modes for typical woofer might be around 5kHz. Isn’t cutting at 2kHz too close - especially for 6dB/octave? In comparison my 3-way speakers cut at 230Hz and 3kHz - outside of "sensitive" zone.

Also, I agree with you that small sweet spot, caused by beaming, might be advantage in acoustically bad rooms, but that’s only if you listen alone. For me wide sweet spot is very important. If I’m not mistaken beaming for 6.5" drivers starts around 1.5kHz. Crossing at 2kHz or lower might help but you need tweeter with very low resonance frequency. I’m not sure what it is, since I don’t design speakers but suspect that it is around 1kHz. My speakers should beam (6.5" midrange) but they have wide sweet spot. Perhaps weird design of the midrange makes a difference (ferrofluid instead of spider web suspension and the wide flat disk instead of dust cap)

http://www.hyperionsound.com/Images/HPS-938.jpg

1. Isn’t crossing at 2kHz or lower in the range of female voice, that has fundamentals between 350Hz and 3kHz?

I refer you to wikipedia on this:

https://en.wikipedia.org/wiki/Voice_frequency

2. Isn’t crossing below 2kHz to close to resonance of most tweeters? I’ve read recommendation to keep crossover frequency at least 1-2 octaves above tweeter’s resonance.

It's at the bottom end of most tweeters, yes. Usually the rule of thumb is to be 2-3x the resonance. What really matters though is not the resonance but distortion and excursion. That is, overwhelming the tweeter. So your choice in tweeter, as well as the slope and knee point matter.  The ring-radiator I use in my desktop speakers is the "deep chamber" version with significantly lower usable crossover point than the normal variety.  The Mundorf AMT I use in my living room has awesome power handling, distortion and a relatively low resonance point.

The crossover also matters. A tweeter may be able to safely be crossed at 2kHz using a fourth order (24 dB/octave) filter, but 5 kHz using a first order filter (6 dB/octave). You see this with the Joseph Audio speakers discussed in other threads. With a fast drop off they push the tweeter lower than average. 

3. Break-up modes for typical woofer might be around 5kHz. Isn’t cutting at 2kHz too close - especially for 6dB/octave? In comparison my 3-way speakers cut at 230Hz and 3kHz - outside of "sensitive" zone.

This really depends on the driver and crossover, and what exactly you mean by a "woofer" or "mid-woofer." The combination of slope, and filters used in the woofer may help push the usable range up. 

Also, I agree with you that small sweet spot, caused by beaming, might be advantage in acoustically bad rooms, but that’s only if you listen alone. For me wide sweet spot is very important. If I’m not mistaken beaming for 6.5" drivers starts around 1.5kHz.

Even if a 6.5" starts beaming, it is not like a LASER. It doesn't switch from omni-directional to flash light at 1.5 kHz. It just gets narrower as it goes up. If your tweeter's dispersion matches you will still have very nice sound off axis, as the entire speaker will seem to diminish, and not just one particular range.  I do not think that a 6" mid-woofer in a 2 or 2.5 way is a terrible idea at all, or that you will have a pin-point sweet spot, but it can give you added clarity when you are constrained in where you put them.

There are many designers who push the idea that crossovers are bad. Either you want no crossover, or 1st order, or you want the crossover completely out of the vocal range, etc. I'm not really with them. Personally ( and I do not insist that you agree with me ) I have not heard a problem with a well implemented crossover in the 1-3kHz range.  I have also not fallen in love with Thiel or Vandersteen or any other perfect time aligned speaker. 

I'm happy to have learned that at least on this subject, Joseph Audio agrees with me, and none of their fans mention any sort of discontinuity in the vocal ranges. 

Best,

E

@kijanki - This is probably not for you, but here is a very different type of speaker that has a lot of fans. The Seas A26. 2-way with a 10" mid-woofer and single capacitor crossover (6db/Octave):

https://www.madisoundspeakerstore.com/2-way-speaker-kits/seas-a26-10-2-way-kit-pair-based-on-the-cla...

You might investigate it and see why people like it so much. :) 

There is no low-pass because the woofer is so very well behaved. 

Best,

E