Which sounds better 2 way or 3 way speaker design

@ditusa wrote:

See here a two way monitor with attributes of a three and four way design.

Mike

+1

OP: There are a lot of variables involved here. As has been pointed to by several in this thread already it’s about the design goals and juggling different trade-offs, however pragmatically speaking design goals may take a backseat to what’s dictated by the physical outlay of the speakers and the kind of drivers that’s typically used; a 1" direct radiating dome tweeter only goes so low (i.e.: ~2kHz), and in a 2-way design an 8-10" woofer/midrange is about as far as it goes in size to sufficiently "meet" that dome tweeter above, and at the same time avoid severe beaming or break-up modes. The woofer/midrange in such designs will cover most of the voice fundamentals (both male and female), while harmonics are sitting much higher in the treble range of the tweeter. The downside is IMD and Doppler distortion with a single driver covering bass both LF and midrange, and coming down to it there’s also only so much such a driver pairing can do macro dynamically. The power response at the crossover usually isn’t great either, making more obvious there’s a driver division here. Introducing a dedicated and well-implemented midrange driver for a 3-way design (i.e.: where a direct radiating tweeter is used) to my ears tend to be an advantage, both in freeing the mids driver of LF and being given the opportunity for more woofer displacement, even if it means high-passing in the lower midrange area.

On the other hand, waveguide loading a fitting, relatively low fs 1" dome tweeter with a properly sized and designed waveguide can significantly lower the crossover point to the woofer/mids (fairly comfortably down to around 1kHz) while also providing for a smooth directivity pattern at the crossover, significantly lessening the influence of crossing over in the vital midrange area. This way a larger woofer/mids can also be used with up to about 12" in diameter, and with a higher sensitivity pro woofer the dome tweeter can be replaced with a compression driver, and now you suddenly have a high sensitivity 2-way design with smooth directivity characteristics at the XO and prodigious output capability. Depending on the specific pro woofer choice LF may be restricted and which then calls for augmentation down low with subs. This way we’re entering what’s effectively a 3-way design of a different type, and with the further opportunity to highpass the woofer/mids driver with even cleaner lower to central midrange to boot. To my ears such an effectively 3-way waveguide-loaded design choice has a lot going for it.

Many of the larger high output JBL designs with pro/studio origins (as referred to by poster @ditusa) adhere to above model being waveguide or horn-loaded 2-way designs with compression drivers and 12-15" woofers - sometimes augmented with a super tweeter above 10-15kHz, but which nonetheless doesn’t deter from the fact that they are basically 2-way designs. Myself I also prefer what is basically a 2-way high efficiency design variant crossed at just over 600Hz, though augmented in either end of the frequency range with subs and dedicated high eff. slot tweeters (i.e.: <85Hz and >11kKz). With only a single XO-point in most of the audio band that clears the power region and has neat power response, the augmented areas, and thus technically a 4-way setup, help in ways that doesn’t impede with but rather exacerbate the basic traits of a 2-way approach with a virtually unlimited macro dynamic envelope to boot. Being also that my speaker setup is configured actively, delay has been carefully implemented at the XO points, and having most of the fundamentals of the central midrange + harmonics covered by a single large format horn + compression driver element is a major advantage.

@sounds_real_audio wrote:

Not sure anyone knows what a two and a half way is

Come on..

@rauliruegas wrote:

Now, a woofer in a 2-way design usually crossover around 2khz and the most critical frequencies are handled by that woofer and it’s here where is developed that high IMD due that that woofer handled from around 40hz and up and that developed IMD puts a lot of " dust " in the midrange and in the HF because we have to remember that everywhere are developed harmonics that starts in the bass range.

+1

@toddalin wrote:

"Dedicated midrange driver" is typically an oxymoron and very few three-way systems will not put some of the midrange in the woofer and/or tweeter. You would need to run the driver from ~80Hz-~4kHz for it truly to be "dedicated" to the midrange.

True, referring to a midrange driver as "dedicated" is with most any speaker design incorrect, and that’s even without taking into consideration the harmonics which are somewhat higher in nature and are said to extend an octave or two beyond ~4kHz.

However having a high efficiency woofer section with prodigious displacement area that’s high-passed steeply below ~80Hz bodes well for covering the lower range of the midrange, not least considering that it’s effectively freed of LF and in all but the most insane SPL situations will see virtually no visible excursion. That’s something very few speaker designs can make a claim to do.

@rwwear wrote:

Don’t dismiss 4 ways.

+1

There are different approaches to a 4-way (or any other -way) design, of course, but as I have outlined earlier I prefer what’s essentially an augmented, high efficiency 2-way system based on a large format horn/compression driver crossed over to a 15" direct radiating woofer (or two of them) in the 600-650Hz region (horn-loading is arguably even better here, but its upper end range is limited and thus creates new challenges for the mids/tweeter meeting it). Large pro woofers provide critical displacement area, high motor force and headroom in the important power region while having limited dispersion (and excursion) due to their cone size, and coupled to a large, fitting horn/CD will match the directivity pattern at the XO (where the horn will still control directivity) for good power response here and a much smoother perceived transition. Also important is that a large, 2" exit horn/CD provides for much better energy and physicality its lower region crossing over to the woofers compared to smaller exit horns, which is why the midrange from such a large format horn/CD + woofer(s) combo truly excels in most every parameter with its coherent, unforced, and uncluttered clarity and presence. Well implemented, think the 3" ATC midrange dome or larger panel speakers on steroids.

Such a 2-way design, depending on the specific 2" exit compression driver with its 3 or 4" voice coil/diaphragm, will typically need augmentation in the upper octave, but fortunately blending in a dedicated, high eff. super tweeter at or slightly above 10kHz isn’t a critical XO-region - what matters is integrating such tweeters properly. Same goes with the lower end of the woofer section; high-passed in the 80-100Hz region and augmented with subs they’re virtually freed og LF and visible cone excursion and will perform even better (with 6-10dB more headroom) from the upper bass on up, not to mention match the horn section above more seamlessly. If configured actively the best integration can be had with elaborate delay settings etc.

Choosing or having the crossover region(s) more or less chosen, depending on ones design preference, is a compromise in every variation. The challenge is how to work around them and take advantage of a given approach and the drivers/horns used. A driver covering the entire midrange fundamentals from LF on up in an unassisted 2-way system is a good outset, at least in theory and a limited practical context, but the woofer/midrange used will need to be fairly small (i.e.: 6-8") to extend high enough in its upper range, and this again presents challenges (not to mention being counterproductive) for its abilities into LF territory, in addition to IMD and Doppler distortion acting both as a non-highpassed woofer and midrange. Neither the woofer/mids or typical 1" direct radiating dome tweeter can be expected to perform their best in the upper and lower end respectively, macro dynamics are limited and headroom is more or less nonexistent. I’ve heard quite a few very good such 2-way speakers though, and in smaller to moderate spacings at no more than moderate SPL’s can be fine performers. A friend of mine is using a pair of great sounding and subs augmented Stage Accompany M57 speakers with dual 12" high eff. woofers and a high eff. ribbon type midrange/tweeter in an MTM config. crossed at 1.5kHz, all actively. So, 2-way main speakers as well (i.e.: a 3-way system w/subs), but very different to the previous, low eff. 2-way solution mentioned for a variety of reasons. A high eff. 12" woofer can be an excellent central to lower midrange driver, but exhibits more "character" in its upper range compared to a 2" exit large horn/CD solution (that I use) in the same region, which is audible in particular with piano and the lower range of violin. Conversely the ribbon driver extends higher than the large horn combo, which then needs super tweeter assistance for what amounts to a 4-way system in total (also subs-augmented). And on it goes; different solutions, different strengths/challenges.