Originally Posted by Todeseng3l
The size of the woofers are almost irrelevant to this discussion, I don't care if they have eight 15" woofers. A smaller cone with greater capacity for excursion can produce the equivalent of a larger cone with less excursion.
Yes, however, more excursion equals more distortion, unfortunately. Many single driver subwoofers put out distortion in excess of 10%. That is why Legacy uses more large drivers (more piston area) as you go up their line. Simply put, More piston area = less excursion = lower distortion.
Cabinet size and design will have a greater impact on the low end frequency response of a speaker than the cone will. A subwoofer only has to accommodate low frequency ranges as opposed to the full spectrum of a loudspeaker that has to cater to a much broader frequency range, therefore a subwoofer can have an uncompromising design and contain generally a larger volume than a full range counterpart. Of course there are always exceptions (especially with speakers that have a significantly large footprint) but in the case of the Focus SE the cabinet is only about 15" deep and it is a ported design, this would be the first indication to me that during the enclosure design, compromises were made.
Have you heard the Focus SEs in your room? I would not call it a "compromised design", but rather an Optimized Design... Bill D. has been refining the Focus SE for almost 20 years! I can assure you that the bass reflex alignment and cabinet size is optimized for the drivers in the Focus SE.
Additionally, just because a stand alone subwoofer only has its one job, does not mean that a fullrange speaker cannot do an equally good job in producing bass. A fullrange speaker like the Focus SE has more woofers (4 per pair) dedicated to the 18-120 Hz range than most subwoofers on the market have. (Again, More piston area = less excursion = lower distortion).
And, the crossover in the Focus SE ensures that the frequency range the woofers handle is optimized for the drivers and the cabinet design, just like in a standalone subwoofer.
Regarding internal amplification, I can only make assumptions given that what I have requested (SPL/Frequency chart) is not available for these speakers. Unless the Focus SE have one of the most efficient woofer designs in the world (I already know the spec sheet says they are 95.4dB, again spec sheet info rarely translates to real world performance)...
I'm not convinced that is an accurate statement.... many reviews I read in Stereophile magazine test speaker sensitivity, and the results are usually very close to the manufacturers claim.... Also, I know Bill Dudleston personally, and he is not one to exaggerate, especially when it comes to speaker specs...
...it will take a lot of current to drive the woofers and the rest of the speaker to produce the output equivalent to a dedicated sub with a separate amp. To do so, you would basically be demanding that a single amplification source have the power/capacitance/drive etc. of two separate amplifiers....
Perhaps you are right - so just use monoblocks on the Focus SEs, as I know some people do! Emotiva makes a great monoblock called the XPR-1 for less than $1,500. It will put out 1,750 watts at 4 ohms - more than enough current, and plenty of headroom. The Focus SEs are even designed to accept bi-amping, if you so desire.
...Look at the AERIS, it has a 1000W internal amplifier dedicated to the low frequency woofers yet the low frequency response (18Hz) and max power handling (500w) are rated the same as the Focus SE. So how in the world are these two speakers going to produce the same output/frequency response (spec'd at 18Hz +/- 2dB) when the AERIS has 500W of headroom to drive 2 woofers + tweeter while with that same 500W the Focus SE has to drive 4 woofers + tweeter? It doesn't pan out....
It's funny that you would compare the woofer sections of the Aeris and the Focus SEs - mainly because they both use the same 12" Aura woofers! However, the bass alignments are different - the Aeris is a passive radiator design, while the Focus SE is ported. In case you are not aware, passive radiator designs require more power than ported designs to produce the same results, which I assume is why Bill D. designed the Aeris with 1,000 watts of built-in power for the woofer section. He really does know what he's doing when it comes to speaker design. :-)
With your logic, there would be no need for a subwoofer in a HT set-up with these speakers (since you repeatedly state they have a spec at 18Hz)....
You are correct - there is no NEED for a seperate subwoofer with the Focus SEs. However, I don't dispute that adding a sub or two (or four) will give you even better performance. In fact, I use seperate subs in my Focus SE based system! The advantages being even lower distortion, increased output, and evening out room modes. I endorse and recommend adding subs to almost any system!
...Like I said before, I don't expect any speaker (that I can afford) to be able to compete with a high-end sub (~$2k) in low end response/output. I am just trying to gauge how much of a compromise will be made if I don't include a dedicated sub with a Focus SE set-up....
Honestly, you really won't miss a subwoofer with Focus SE speakers. Adding sub(s) with them just makes the overall system even better.
...Really all we need to end this discussion is an SPL/Frequency graph, we can see what the output is at 18Hz and compare it to what a subwoofer would produce from which I can draw my own conclusions (which was why I posted here in the first place). I am just trying to make an informed decision as there are tons of competitors in this price range and this is a significant investment for me.
I'll see what I can do, but I have no way of making anechoic measurements, and I really don't want to lug my speakers and subs outside for ground-plane measurements. However, I can tell you from experience, that you will definitely NOT be disappointed with the Focus SEs and their bass performance. Perhaps BrolicBeast can chime in as he has recently gone through this same process and is currently running his Focus SE/Marquis system without subwoofers. He seems to be very satisfied (for now - a pair of dedicated subs are in his future :-) )
If you live within driving distance of Lancaster PA, I would like to invite you to visit my place to hear the Focus SEs for yourself. I hope you can make it!