What's the best 7" & 8" woofers available?

Another Zobel question. The thread is changing direction
here, but since we're on it, and it's interesting, here goes. If we put a Zobel network on the woofer to flatten the reactance spike in the very lowest usable register,
wouldn't this decreased reactance now allow a higher signal
current to flow, meaning that the low end flat response is extended? The limiting factor of the flat response at this point is now the "X-max" total linear cone travel AND the
mechanical cone mass/damping factor (classic mass/spring/
damper system), NOT the electrical damping. If this is true,
shouldn't we look for woofers with high moving mass, long
long X-max (P-to-P), and "tight" non-compliant surrounds?

Rbj..Stehno may know your answer..i can't help you..your question is a good one for madisound.com chat page..over there you'll get very accurate answers..i'm green on the tech stuff..i just ask alot of questions to the designers about certain drivers qualities and then i choose from my top picks..the xover and speaker design i leave up to the designer..i tell him to use premium parts..choosing the "best" drivers is barely half the equation..the easiest part..the many xover options is not an easy task..i'm glad i found a designer with all the measurements for the drivers i like

Rbj. Your question is a very observant one. If you have followed my threads on the single driver subject, you will know that I have been using a network like the one you describe for my own speakers. Yes, the network does lower the impedance spike at the resonant freq. and allows the amp to control the woofer more comfortably at lower freq.s, thereby extending useable bass response and reducing phase shift. However, trying to use long Xmax with a tight cone suspension merely raises the Fs of the driver and takes you away from your goal of lower bass response. The method I used to get good results was to use a network, and tune a transmission line to a freq. half that of the driver Fs. This allows the T-line to handle the output of the lowest freq.s at a higher SPL than the cone would produce, and with shorter excursions. In my particular system, I achieved a full octave deeper bass before rolloff, with this method. In my network without the capacitor, the high freq.s in a single driver system are also improved similarly, with an extension to the high end gained by reducing the gradual impedance rise that is commensurate with rising frequencies. T-line tuning is a bitch, and has some problems like comb filter effects, but they can be minimized with some work. I think that if more people employed a design like this, you would see more single driver systems being accepted as true full range systems. The nominal impedance value of the driver is slightly lowered so an amp with some flexibility in this area is required. Good question.

Thank you TWL. I surmise that current "state of the art"
is bottlenecked at the woofer itself. I am unaware of any
audiophile-quality woofer with an X-max of , say, 30cm.,
regardless of cone material, power handling, etc. I acknowledge that there are several methods, some sucessful,
such as you described above, to extend the bass. Until a
better woofer becomes available, I think I'll comb more thoroughly through the responses of others here, and at other sites. Another thread topic could be the pro/cons
of using, say, two 8" woofers vs one 12", comparing total
cone area, X-max, air displacement, total voice coil winding,etc. (physical ability to create sound waves).
Something like comparing one large intake valve to two
smaller valves, in an engine.

Bob,

There are currently 8 select audiophiles who are involved in building the latest dual mono version of the pre-amp that I mentioned. It will have DACT controllers, Jensen caps, the works. The cost will come in at around $1000 and the wait is 4-6 months. If you are interested in getting one, you'll have to be willing to annie up the money without hearing it first. Let me know if you are interested, becuase after all the parts, chassis, etc.. are ordered, that will be it for this small build.

I will be selling my little pre-amp for around $600 after this deluxe version is finished, so there is another option for you too. It will be sold with a guarantee that it will sonically crush any other pre-amp under $3000, and hold it's own against ANY pre-amp period in terms of detail retrieval and harmonic preservation. There will be no guarantees on the amount of bass, or treble sweetness though, because these things can be colorations of certain circuits and tubes. I also think that the $8500.00 Blowtorch pre-amp may have a little better bass preservation than my little pre-amp (based on my study of it's design). We are talking about a $7900 difference in price though!