Is the 2.5 way speaker the ideal home speaker?

Usually higher tweeter points are achieved with 3-way systems which use a "true" midrange.

Best,

E

Or a small woofer like the Silverline Minuet Supreme. 3.5k crossover point giving way to a beautiful midrange. 

@helomeck.  I made that point early on and it is one of the best advantages. That is why I also like a simple two way design.  Nice post.  

I love my ProAc Studio 148, which I think qualify... 

"The two 6.5 inch units cover bass frequencies but each one has been mechanically tuned to cover mid frequencies. To improve dispersion the upper bass driver has a phase plug whilst the lower unit has a ProAc open weave cap."

So, just idle curiosity, but can a 2.5way have with multiple woofers--that is at least four or more total drivers--or is that a different beast all together? 

I have a pair of Wilson Benesch Vectors. My understanding of their 2.5 way system is 500hz for the woofer, 5khz for the tweeter, and a full range  “midrange”. Seems to work well. 

@tcutter

Yep, the Wilson Benesch Vector is a funky beast indeed!

Not only are they using no crossover on the midrange, they are using 1st order slopes on the tweeter and woofer, but wait! There’s more!

They are also porting the mid-range unit. Not unheard of, but rather rare. Only other speaker I can think of with similar dual-porting is from Sonus Faber.

I don’t think calling it a 2.5 way really does it justice since it really has only 2 filter sections, which would normally be for a 2-way speaker. It’s pretty miraculous they are able to do all of this and still maintain a comfortable impedance that they do.

In some ways, this reminds me of the famous Seas A25 speaker, now available as the A26 kit speakers.

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

Best,

E

@grannyring 

I made that point early on and it is one of the best advantages. That is why I also like a simple two way design.  Nice post.  

My apologies, I overlooked it.

@erik_squires 

I'm not sure I follow, @helomech -

Usually higher tweeter points are achieved with 3-way systems which use a "true" midrange.

That's why I stated, "well designed examples."

I know of quite a few 3-ways that are still crossed over to the tweeter rather low, often in the 2kHz range. Some 2-ways are crossed this low, but it often doesn't work so well IMO. There's no hard rules in any of this, but I rarely come across 3-ways that have the coherency of well designed 2-ways.

Hi Helo,

Interesting! Point me to a low crossover 3-way, please! :)

Though I think JA speakers does this. Their steep crossover slops let them push the tweeter lower than most.

Best,

E

^ Eric,

Revel F206 : 2.1kHz

Monitor Audio Silver 8: 2.7 kHz

Paradigm Monitor 11 v7: 2.2 kHz

Paradigm Persona 3: 2.4 kHz


The first 3 I auditioned extensively. I owned the Silver 8s for a year They all lacked some coherency IMO. 

Interesting! I always assumed otherwise. Especially with the Monitor Audio, that tweeter doesn't really have a lot of low end extension.

Definitely not how I would do a 3-way at all, but then hey, I'm not making the big bucks designing speakers.  It'd get a very lively, composite midrange and cross it over at 3-5kHz 

Best,

E

Eric,

The only 3-ways I currently own are Klipsch Heresy IIIs. I just looked up their crossover point, it's a rather high 5kHz. These speakers still lack coherency unless listening from a distance of 11' or more. I would guess that is most likely due to horn beaming, though the others I mentioned also benefit from such distance. I sit about 9' from the speakers in my main rig. Of all the 3-ways I've tried, none work for me in such proximity. I imagine a design like the Elac Adantes might work.

I tend to crossover at 2 kHz or slightly lower since I have only really made 2-ways so far, and don't have an issue with any coherency. One pair sits on my desktop. The near field listening is a real treat given my living room is an acoustic mess.

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

Thank you Erik.   Link you provided states that range of fundamental for woman voice is 165-225Hz  while I found this:
http://www.seaindia.in/blog/human-voice-frequency-range/

that states: 350Hz - 3kHz for fundamental frequency - about 15 times higher.  I don't doubt Wikipedia and just wonder.  Could this be that "typical" voice is in narrower range while soprano can get 15x (almost 3 octave) higher?   Perhaps it is "talking" (Wikipedia stated "speech") vs. "singing". 

I appreciate your comment about "not laser like" start of beaming phenomena - my tweeters might already provide wider dispersion where large midrange speaker starts to beam.

Be careful reading that. There is a significant difference between the fundamental and the range. The fundamentals are the bottom, pure note. But the range is far higher.

Erik,  Paradigm Studio 60 v2, I had before, was sold at about $1k.  It usually means that manufacturer sell them for $500.  In my company cost of materials is about 30% of the cost of the product.  That would imply $170-200  for three speakers, box, xover etc.  I did not like sound of the metal dome tweeter and found it to be one of the cheapest Vifa tweeters available.  It is very tempting to build speaker using the best drivers available, including underhung motors etc.  Unfortunately I already attempted to replace this Vifa tweeter and to redesign xover with high quality components.  The purchase of Hyperion speakers was direct result of this attempt.  Perhaps I'll learn more and try again one day.

Erik, they stated "fundamental" . For harmonics they claim 17kHz (hard to believe).

I found that high "C" for soprano is about 1kHz, but they can produce "whistle tone" (or falsetto) at D7 or 2349.3 Hz and this is the highest voice human being can produce - hence 3kHz is not even possible.

I am very happy with my Advent Heritage speakers which are a 2.5 way design. This is for two main reasons - they were a little over a hundred dollars including the refoam kit and they sound great. Also they come in a cabinet that is solid pecan front and back. Also they are fairly efficient. Lovely bass extension and nicely detailed treble. It did take several hours to replace the surrounds on all 4 drivers but so worth it. Currently powering them with Kenwood M1/C1 set at 105 wpc. 

It’s been a while since I posted but this discussion is good. In 2004 I bought on an Audiogon auction the Soliloquy 6.3 2.5 way speakers designed by Phil Jones. An excellent review can be found here including crossover specs: https://www.thefreelibrary.com/Soliloquy+Model+6.3+loudspeakers-a097823139  I’ve changed every component of my rig, currently Butler TDB2250, Krell KBL and Denon DVD-3910 and the Soliloquy’s have allowed me to hear the changes. I vote that when done right the 2.5 ways are wonderful.

Boss302

@kijanki

I think the bottom line is that if a driver is crossed over close to 4kHz, it’s covering most of a human’s vocal capability that falls within the most sensitive range of our hearing ability. It keeps the crossover away from the meat of the music. Even if harmonics do extend as far as 17kHz, many folks have trouble hearing freqs beyond 8kHz.

Helo - 

I can't disagree with you in terms of the voice, but I will say, I just haven't found the upper crossover point to be a really clear indicator of performance either way. 

Most of the human voice in singing operates from 80 for very low bass male voice to around 1500 which is above natural female vocals to maybe someone trying to hit an extreme note to impress.
Everything that Erik has quoted throughout this thread is correct.
A couple of things that I thought of reading through the thread.
**Crossing a tweeter low: sometimes its a no brainer, the mid has a dip or peak and you need the tweeter to cover that range for a smooth frequency transfer... Other times, I have listened to the mid and the tweeter both at a given frequency and thought the tweeter sounded better and chose to cross lower for that reason.
The rule of thumb for how low you can cross a tweeter is 2x its resonance at 12db per octave. This can be broken depending on tweeter, but it is a good general rule to follow.
For me an optimal in theory speaker would be a 3 way crossed somewhere around 80 on bottom and 2200 to 3k on top. This keeps the deep bass off the mid which really helps keep it clean and it also keeps the crossover out of any critical vocal region. Of course finding perfect parts to put into practice are not always so easy.
Erik, you’ve done a great job with this thread. Getting folks to understand a 2.5 way vs a 3 way isn’t always easy.
Tim

This has been a great thread for me to understand a little bit better about something I enjoy. Thanks Eric for the thread and Tim with your long term experience in speaker building for all your supporting information.

Very good post , helped to clarify things I kinda , sorta knew .
I'll give you a joke I just heard on the local jazz station .
Announcer was interviewing a local retired trumpet player who still does some sub and gigs around the Twin Cities .
The dude had once played for Lawrence Welk , both of them rolled off the names of some pretty good musicians who played for the bubble man over the years . DJ kinda beat around the bush as to why so many good players
played the corn ball . Trumpet man said , "you have to be a hell of a musician to play that bad all the time "  !

Well I am a huge 2.5 way fan. My fav are the Wilson Benesch. As suggested they use the same size midrange as woofer and work very hard to create a woofer that is as fast as the mid range so there is no loss of coherence. The woofer does woof and the mid because it is 7" can go down to 500hz. I think unlike many 2.5 way speakers the WB's midrange goes all the way up to 5000 kHz and this covers almost the entire midrange with male voices and cellos sounding very full and rich.

@timlub

Everything that Erik has quoted throughout this thread is correct.

Thank you kindly.

@marqmike

This has been a great thread for me to understand a little bit better about something I enjoy. Thanks Eric for the thread

Glad to be of service! What makes these threads interesting is the wide variety of experience and expertise everyone brings to them.

Best,

Erik

As a DIY speaker builder, I've logged many hours building & tweaking crossovers, and one big compromise of a 3-way design is the HP filter you have to put on the midrange.  This is, at the very least a large capacitor to roll off at ~350 Hz, plus a large inductor too for a 2nd order.  These components are now in the signal path of your crucial midrange frequencies, and they're also affecting the phase alignment of the midrange with the tweeter.  You may also need to invert the polarity of the mid driver (or not)... it just depends on other parts of the design.    The 2.5-way design has fewer crossover components in the way of the midrange, and has more low end capability than just a 2-way.  There still will be some phasey issues between the 2 woofers as the lower woofer rolls in to align with the upper woofer.   I admire the idea, but I've never built or owned a 2.5 way design.

@microlab
If you properly account for the resistance of a coil and use quality parts, I’ve not seen a problem with crossing at 350 hz. A simple cap will typically run between 50 and 150 mic’s. An inductor can certainly add phasing problems... using an inductor and porting can cause real phase issues in a woofer, but with proper crossover point selection, using driver compensation and quality parts, most issues can be avoided. I would highly recommend that when you can to just avoid using 12/12 slopes, that will normally stop the need of having to reverse polarity. 6/12 or 12/18 butterworth are both more phase coherent than 12/12 anyway. If you need to run 12/12, choose linkwitz slopes.

Bump start this thread as I have just come across it

My take on 2.5 ways is that the benefits are only if using roughly 5.5" driver size. Plus points- covering 400hz and below is covered by the surface area of 2 drivers. So baritone vocal range can be surprisingly good with 2.5ways. Also as 2 drivers share bass duties the top midbass driver has less work to do (no bsc) compared to a 2 way and mids will benefit. Still, a 3 way is better in this respect.
Also cab size is kept compact. I dont like the term ’WAF’ but a small footprint with good bass output is attractive.
One disadvantage is a sometimes boomy bass which requires bringing the speakers out into the room. Which kind of defeats the purpose of compact and room friendly. This is due to the 6db gain from the bottom woofer. Typical room gain adds around 2db lift at lower frequencies, so the baffle step compensation of adding .5 woofer can often be too much.
Hence surprised we dont see more sealed design 2.5 ways imo.

I think it is helpful to think of speaker design as largely being an evolutionary process based upon consumer demand. There is a reason why large Altec Lansings and Klipsch K-horns gave way to acoustic suspension like the AR3a and KLH to Advent and then to the predominant design of the day-narrow baffled deep floor standers that are ported and either 3 way or 2.5. 
There is a reason too why the outlier designs like planars, wide baffles, open baffles, time arrays, plasmatrons, you name it remain outliers. 
It is largely a matter of being able to deliver the most-looked-for audio attributes for an average consumer's room with an average consumers choice of amplification at a reasonable cost. It is a matter of survival of the fittest. The companies that thrive innovate and evolve and their research and development over time begins to converge on a common solution to these consumer wants. 
In the Preamp/Amp forum someone asked about amplification for the Spendor D7.2 and I tried to help but unwittingly derailed the thread a big when I compared and contrasted the D7.2 with the DeVore O/93's. I own both. I was thinking of this very concept while describing what makes the Spendors so attractive. They do the imaging, soundstage, and midrange things exceedingly well. Most but not all present-day audiophiles want these attributes. Standmounts do these things exceedingly well too at the expense of bass and authority. But again, my main point is that the DeVore O/93's play to a whole different suit of priorities that for better or worse, are sought after by a minority of high-end listeners. I happen to prefer the DeVores but for variety I love the Spendors too. 

Hi. Newbie here. I've been reading this thread with interest and wondered if it might be helpful to briefly summarize the basic rationale behind a 2.5-way design.

It's really a question of performance versus cost. Multiple woofers deliver more bass output than a single woofer. If those woofers are relatively small -- say, 6.5-inch or less -- they should also deliver reasonably good sound in the midrange. However, if they are all operating in unison up to the crossover point with the tweeter, there will be anomalies in the midrange stemming from the physical separation of the woofers. So only one woofer (usually the one closest to the tweeter) is allowed to operate that high; the other (there could be more than one, although I can't think of any examples) is rolled off at a much lower frequency.

A 3-way design should preferable, at least in theory, but it requires an additional type of driver and a more complex crossover network, and both of those increase the cost.

A 3-way design should preferable, at least in theory, but it requires an additional type of driver and a more complex crossover network, and both of those increase the cost.

and often degrades transparency.

I'm not sure I follow, @helomech -

Usually higher tweeter points are achieved with 3-way systems which use a "true" midrange.

It's just my experience that 3-ways often lack the transparency of a good 2-way, I can only guess it's due to the additional crossover components. A good example is the 2-way Maggie .7s vs the 3-way 1.7s. The latter is less resolving.

@helomech

That's interesting, usually three way speakers are considered ideal due to the midrange covering the entire human voice and much of the piano without the crossover involved.

I wonder if your hearing more bass boominess from 3 way designs?

@helomech

That's interesting, usually three way speakers are considered ideal due to the midrange covering the entire human voice and much of the piano without the crossover involved.

I wonder if your hearing more bass boominess from 3 way designs?
 

Yes, some 3-ways have a single driver covering most of the midrange (though many still crossover to the mid around 2kHz, largely negating that advantage) , but even though the crossover point may not be smack in the middle of the midband, it still requires a more complex crossover with additional components in the signal path. The whole signal path of the midwoofer need be considered when it comes to signal purity, not just the crossover points.   

I can't tolerate much bass boom, so no, that's not the issue. I have a room that can accommodate very large floorstanders. I prefer large 2-way standmounts with subs to augment the bass.

Another issue I find with many 3-ways is their small and/or recessed vocals. A vocalist simply won't sound as full and present through a 3" cone as they will via a 7+" cone, nevermind the beaming argument. This is why some designers, B&W for example, refuse use small mid cones. 

I understand the theory behind the proclaimed advantages of 3-ways. It's just that in many cases, my ears cannot detect a practical advantage outside of maximum loudness capability. They can play louder before compression kicks in, or before complex music trips them up, but it comes at the cost of lower resolution at moderate volumes. That's been my experience. 

Two-and-a-half-way fan here!  I've had a few in the past and currently have a pair (JBL Studio 590's).  I think the advantages of the design mainly fall in the value factor.  And I'm all about the value! :)

To my ears, my 2.5-way Spendor D7’s sound swell. They have fairly sophisticated rear ports, but I still need to bring them out into the room (which is a large room) or I get a little too much bass. That said, I supplement with REL S/5 to get the bass in the 20-30 Hz range, but I dial it way back on the sub crossover (to about 35 Hz) and volume (just about 5 clicks of 40 I think).


Haven’t yet ventured into room treatments and I know there’ll be hell to pay from my better half if I ever show up with some gawd-ugly looking foam treatments for the walls but if I know myself eventually I’ll go there and risk the wrath ...

So... at the risk of complicating things further and having my head handed to me, can I throw another newbie question into the mix?  
If I used a 2.5way + a sub w a high-pass filter ,removing everything below maybe 80hz that goes to the mains, would that help not only dig deeper (since the 2 mains woofs are only 5.25"-ers) but also clean up the mid-bass, since that driver would be relieved of the larger excursions needed to produce the lowest bass and could (just like in a 2-way w that sub) create cleaner/more "present" mids? That would keep the cabinet relatively small/narrow compared to a big 3-way, even if the sub takes up room, (And in my case it would keep upgrade cost down, since I already own a sub w a variable high-pass filter.)  The specific 2.5 I'm looking at is the Elac Carina FS247.4 if anyone has direct knowledge of it.) Thanks for your thoughts. 

Hey @mmmikeymike 

 

That's a fine idea.  I suggest you plug your main speakers though.  It will further reduce excursion, and may make integrating with the sub easier.

Thanks Eric, and thanks for this thread - I'm learning (a lot) along w you here! The Carinas don't come w fitted plugs, and I've never actually plugged ports before. Any suggestions on what material to use, since I'll be making them myself as far as I can see.

Always years behind, or not active originally, but a great topic.

Lucky to buy (trade/scrounge) used original Raidho D2s back in 2016. They replaced Dyne Sapphires (3 way and much larger).

For a 2.5 way (150 and 3k) with two tiny 4.5" mid/woofers, and using the DSPeaker Anti-Mode 2.0 (for room/bass correction and to tame the Raidho's built in hump) they play nice and smoothly down to 30Hz in our 20 x 17 room, but they sure don't do rock concert loud (low 90s peaks tops, or popping!). Fabulous fast tight clean and rich sound with those blessed sealed ribbon tweeters.

Still I like having three SVS sealed subs passed low (35, 40, and 45 for now) and not easily audible with most music which I like.

But if I'm going to run three subs, they could very easily do more than they are, and consequently relieve the D2s of that really deep bass output. Plus that should also benefit the mid-range and yield a bit more dynamics (I know I shouldn't ask for more volume...but it's so nice).

The W4S integrated makes the D2s sing, but I have not been able to successfully split the pre-out line-level signal to subs and DSPeaker unit (which could easily high pass the D2s however blended best). It yields mono and I'm stuck. I need to think harder on this.

Great thread Erik, and gentlemanly conduct on your part at all times. I'd have groaned inside a few times...  :-)

 

@mmmikeymike - Clean sports socks. :)  You don't have to overstuff the whole port.  If you can roll up a sock and shove it in, that's enough.

@musicaddict  Raise that crossover frequency, if you can!! Most find the reduction in distortion of the mains totally worth it.

@erik_squires Thanks for the suggestion, especially since like most men, I have a small pile of unmatched socks that lost their mates somewhere in the laundry process and I keep thinking the other half will reappear someday. If I like the outcome, once my Carinas arrive and I play w them a bit, I'll probably try to fashion something more permanent, since I picture eventually trying to fish a balled-up sock out of the speaker guts without damaging anything -that's just how my universe works LOL. Will do some digging to see if cork or foam or what might work for a custom fit. 

I'll probably try to fashion something more permanent, since I picture eventually trying to fish a balled-up sock out of the speaker guts without damaging anything

@mmmikeymike 

Hahah, don't do that!! You don't need to shove it in far.  Shoving the sock in deeper does not help.  Just so the majority of air is prevented from moving freely from the inside to the outside, and you can easily pinch it with your fingers to pull it out.  Really really helps to be able to measure the system and adjust EQ accordingly after plugging.