Most people seem to think that a 3-way done well will have less compromises than a similarly well done 2-way but does this mean when the speakers are trying to run full range without a sub handling the bottom octave? Basically, what I'm wondering is, if I have a good subwoofer, should I look for a good 2-way or still look for a 3-way? Thoughts appreciated.
It is very possible to do 2-way plus subs. This assumes you make good choices. If you begin to mess around with narrow bandwidth devices like horns, 3-way plus subs might become an option to consider. If you use specialised drivers you could also force yourself to consider 3-way, and not necessarily for good reason.
How are you with a crossover, do you make the right acoustic choices as a part of it? Those choices should make the band decisions for you, otherwise your concerns might not count for much.
How are you with a crossover, do you make the right acoustic choices as a part of it? Those choices should make the band decisions for you, otherwise your concerns might not count for much.
Precise goals, venue, application, budget, potential constraints on size/placement of enclosures are interacting critical factors in the calculus of what is "best" for any particular system.
Short answer is
- there is no "best", virtually all systems contain some compromises ;
- yes, it is possible to obtain satisfactory results with less than a 3-way system plus "subs";
- some DIY Audio members - particularly at the "full-range" forum find that wide-band drivers operating over at least 7 octaves, plus woofers / subs are more than adequate for their needs.
Short answer is
- there is no "best", virtually all systems contain some compromises ;
- yes, it is possible to obtain satisfactory results with less than a 3-way system plus "subs";
- some DIY Audio members - particularly at the "full-range" forum find that wide-band drivers operating over at least 7 octaves, plus woofers / subs are more than adequate for their needs.
A well executed 3-way design uses a sealed midrange for excellent transient response over a more optimal operating range. Even modest size 3-ways produce stereo bass down to 40Hz.
Ear level is 36"-39". You will need to build a sturdy stand to lift the tweeter of 2-ways up to ear leavel. So why not put a woofer down there??
A pair of 8" (Sd=225cm^2) woofers is the common design if you want to keep modest panel dimensions.
-Simple baffles like Dennis Murphy all-Dayton TMWW.
-Beveled baffles all-SB TMWW build ($300drivers + $80 Xover)
SB Acoustics 3 ways
A single (Sd=530cm^2) 12" woofer will generate the most coherent bass wavefront plus superior sealed-box transients to -F3=37Hz with SB34NRX75-6 in 4cuft.
Ear level is 36"-39". You will need to build a sturdy stand to lift the tweeter of 2-ways up to ear leavel. So why not put a woofer down there??
A pair of 8" (Sd=225cm^2) woofers is the common design if you want to keep modest panel dimensions.
-Simple baffles like Dennis Murphy all-Dayton TMWW.
-Beveled baffles all-SB TMWW build ($300drivers + $80 Xover)
SB Acoustics 3 ways
A single (Sd=530cm^2) 12" woofer will generate the most coherent bass wavefront plus superior sealed-box transients to -F3=37Hz with SB34NRX75-6 in 4cuft.
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Well, to add a little more info, I built a sub as a work study project in anticipation for building my main speakers. I don't need to use the sub all the time and for a lot of music it would probably stay out of the equation but I have a MiniDSP 2x4HD and the sub so far and a pair of speakers that I am not happy with (PSB Imagine T towers) that I plan on replacing with a kit pair. I am new to crossovers so would prefer to stick with a well respected design. I have a few other threads that mention designs I have considered but I wanted some opinions on whether I should be looking for 2-way or 3-way.
To create the illusion of an audio point source from multiple drivers, all of the drivers at that frequency should be spaced no further than one-quarter wavelength of that frequency. With a 3-way cabinet it is easy to meet this goal with typical 100-200Hz crossovers between a good sealed midrange and woofer (34" - 17" separation). This crossover frequency range also allows the woofer to provide (variable) baffle step compensation. To meet this goal with a single far-spaced subwoofer requires a crossover frequency of ~80Hz-60Hz, which typically requires a ported midrange.
There are several advantages to a good full range 3-way design, especially when stereo music is the major use. Stereo bass maintains phase information which allows most listeners to hear location queues. Find a cabinet style which fits your room and wood working skills. Some wood shops offer CNC services.
There are several advantages to a good full range 3-way design, especially when stereo music is the major use. Stereo bass maintains phase information which allows most listeners to hear location queues. Find a cabinet style which fits your room and wood working skills. Some wood shops offer CNC services.
I went 3-way with a sub for my (very) small A/V room.
Main speakers -SEAS L18 bass, Morel EM1308 mid, SEAS 22 TAF/G treble. Exceptionally clear and open sound with top-notch vocals. Crossover is 860hz and 4KHz.
Sub has a rear firing Peerless 12" XXLS and a BK300 plate amp. This is a prototype and isn't finished yet, though it sounds good and gets well below 20hz.
Main speakers -SEAS L18 bass, Morel EM1308 mid, SEAS 22 TAF/G treble. Exceptionally clear and open sound with top-notch vocals. Crossover is 860hz and 4KHz.
Sub has a rear firing Peerless 12" XXLS and a BK300 plate amp. This is a prototype and isn't finished yet, though it sounds good and gets well below 20hz.
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That look awesome Zuhl! Finally someone is using dome upper mid.
I just finished optimizing crossover for 4 way with two domes per side.
One Hivi planar tweeter, two 2" dayton domes with face plates removed to form mtm as close to tweeter as possible, two 6" dayton midbass per side, and one 15" jamo woofer per side.
Passive for upper 3 ranges, active split at ~150 Hz and biamp. Boy does it sound good! And measures equally well. I use no eq now.
I just finished optimizing crossover for 4 way with two domes per side.
One Hivi planar tweeter, two 2" dayton domes with face plates removed to form mtm as close to tweeter as possible, two 6" dayton midbass per side, and one 15" jamo woofer per side.
Passive for upper 3 ranges, active split at ~150 Hz and biamp. Boy does it sound good! And measures equally well. I use no eq now.
You should use 2 or rather +4 subwoofers to get a real advantage over a pair of fullrange speakers, not just deeper bass and lower distortion.
The problem with 3-ways in your case is if the woofer is crossed over too low to give you any advantage over a 2-way, suppose the woofer is crossed at 100hz, not so helpful if you intend to cross to multiple subs in that region. You should look for xover at ~300Hz for the woofer.
a good 2-way will do just fine FR or not, atleast the ones ive built.
Its more about Vd or power handling and thats something you need to figure out so you dont choose an inadequate speaker.
For me, one 8" woofer per side when crossed over to subwoofers @ 80Hz is almost always enough.
So i plan to build a 2.5way just to always have enough headroom.
Rather than crossing to subs, let the main woofers run their range and use the subs to fill in the gaps, room wise and otherwise.
Zuhl - that gentle (first order?) roll off of the dome mid reminds me of the 'filler driver' concept (originally a B&O idea) - was that an influence? I've only seen it done with a cone mid before, is the filter complex?
Sorry for OT - please resume normal programming
The crossover is a simple 2nd order (electrical) but with some important differences. The mid high pass inductor is oversized and in series with a large resistor. This makes the curve more gentle but, more importantly, it adjusts the phase to match the bass. This is what allows the mid to be so open and detailed.
I don't obsess about roll offs. Getting the phase right is more important as this allows the speaker to sound coherent and integrated. Providing you're not making a drive unit operate outside of its comfort zone then a gentle roll off is fine.
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