Well problem is 100 Hz first crossover and two woofers which go with it and they can do approximately 0 dB at that frequency all together, port can extend to their - 6, additional +3 when it's unified wave (45 Hz and under and in between partially summing up to +3 gradual from 75 Hz) so you do what you can and that's 80 Hz crossover (high pass on mains) and don't need or want their port reinforcement anymore so you might as well plug them and at least it's not a problem with F5 to do that. It's fine to stay 2.1 and more so use second and other subs firing opposite ways and creating equal pressure chamber. You can't stress them out but that doesn't mean they won't sound good as it is, anyway you can't do anything about how low first crossover in them is set.
Another problem of F5 is relatively low efficiency (quote 85 db/W really more 82). You see every advantage in one way is disatvant in another. Harder the cone is it will behave more linear (Xmax Lin) but it will also be heavier and there for for their cone diameter less sensitive. E DBR62 is great example of a job greatly done and even took him (A. J.) a lot of work in cuple iterations to get there especially regarding the enclosure with similar 6.5" woffer's staying in really affordable category.
If you want example of maxi bookshelf's done almost to previously described In affordable category take a look at Wharfedale Linton's 85 (A. E.) or less affordable but still somewhat that in flor standing one's at Polk R700 (if you can find them anymore).
I'm currently very happy with these speakers and I've only had them for a year and a half.
I studied them carefully and listened to them before I pulled the trigger.
I paid 350 Euros 6 years old speakers back then.
I believe Andrew Jones lowered the crossover so low because he had to balance what he had so he had to make some compromises, and that was at the expense of the cabinets and crossovers. In my book this is a plus,it doesn't intrude on that sensitive vocal area 100-2000hz range.
Wharfdale Linton 85 is great speaker but 3 times the money of mine little tower's...
Mine has two 5,25 while Linton has one 8 inch?
I guess same output?
Same aramid fiber cone's,25 mm soft dome.
More or less similar curves, the only difference is that 8 inch is crossed at 630hz?
Is that too much?
Also I believe F5 has little better frequency response without the grille.
Linton
F5 directivity
Linton directivity plot
Mostly I just need a boost in the low end around 40-110 without raising that sensitive area above 100 Hertz and muddy the voices and instruments that have fundamental notes above that area.
I listen to a variety of music and I haven't noticed that there's much below 40hz that's audible.
Anyway I feel like I I steal output from the speaker if I crossed them at 100hz.
Robbing them dinamics that 4 drivers has and I only have one Active 8 inch woofer and that is not enough for 20 M³.
I have enough power for them.(120W at 8 Ohms.
The reason why they are so inefficient 83-4db is because they have only 30 liters of internal volume dividend 10 for middle driver and 20 liters lower chamber volume for 2 woofers.
So they have a very low volume of the box, but I have to move them at least 40 cm from wall,otherwise I get to much reinforcement.
Another part is impedance that is very high. This is what Polish magazine had to say about that:
"On the other hand, this results in low sensitivity, and therefore low pressure at a fixed voltage at the terminals. At the standard 2.83 V, the characteristic oscillates around about 83 dB, which would be a poor result for a 4-ohm speaker, but formally for an 8-ohm speaker (due to the 6-ohm minimum at 100 Hz), and in practice even for a 12-ohm speaker, it is a good result, because considering the efficiency at 1 W, this result is comparable to about 87 dB in a 4-ohm speaker sensitivity measurement. The manufacturer declares an impedance of 6 Ω, missing a good opportunity to boast at least 8 Ω, which a large group of customers are looking for.
The fact is, however, that the F6 will not "extract" the maximum power from many amplifiers, and playing much quieter with a certain gain knob position will give the impression of a speaker that plays "weakly" or even requires more effort from the amplifier - which is completely beside the point of the phenomenon from the electrical side.
The processing characteristics are well-balanced, very stable (minor changes outside the main axis), even nicer than with the FS U5 Slim (where the treble level was lowered); the wide band of 36 Hz - 20 kHz can be fit into a narrow path of +/- 2 dB, which even the manufacturer does not boast about (stating the band of 39 Hz - 20 kHz without tolerance); a drop of -6 dB in relation to the average level is noted at 33 Hz - this result is all the more valuable because it was obtained in the room.
I tried Dirac on them since they are obviously design with idea more headroom then more sensitivity, but I didn't like the outcome.
Dirac is so agresive.....
The best setup so far is far from corners and one small sub in the corner behind the left speaker.... any help is welcome.
Il try middle position and post some pictures of measurements.
