Quote from: firev1 on March 04, 2013, 05:17:31 PM

I know its not fair to compare but are full-range's generally 'faster' than the Seas coax? I would love to go active anytime but I have no expertise on building speakers so hopefully will learn with time.

I would not categorize the Seas as "fast". Low efficiency designs never are. It's all about compromise. I'll say much more later when I get back home about pluses and minuses. Even active has minuses. The Fostex is almost stat fast. But with much more impact and punch.

Something about low efficiency designs I've heard (< 90 db/w) don't really lend themselves to low volume listening. Like I've felt the need to turn them up, don't know if it's from lack of resolution or what, but it could be the speed thing.

You guys talk like it's exclusive to speakers.   

True, always felt that my current speakers have no dynamics at low volumes. It would be interesting indeed to hear the demerits of active crossovers. I tend to listen pretty loud in the living hall though when no one is around occasionally(80db average for short periods). The only thing in my experience that I can listen at really low volumes and be satisfied with is the HD800 as I have no particularly efficient speakers.

Some random related thoughts:

• Could rubber speaker surrounds rob the drivers of ability to reproduce soft sounds? I've noted high-efficiency drivers tend to use foam or paper surrounds. Foam or paper surrounds are of course less durable than rubber.
• Is it that the arc-welding amps lose that purity of tone, or is it because arc-welding amps tend to be used with low efficiency (but usually) very accurate speakers with complex crossover networks which rob the sound of its purity. I know we are getting into BS audiophile terms now, but there's really no way of how to put this. I tend to notice that transducers without crossovers have a purer tone. For example, the ER-4S has a certain purity to the sound compared to the UERM, even though the ER-4S is more colored.
• There always seems to be something in the way when there is a passive crossover in the signal path. Passive crossovers (2nd order) consist of at least one sizable capacitor and inductor. There are usually additional caps and inductors for baffle-step correction, and another set of RLC components parallel to the driver for impedance correction. Considering how a SE tube amp maybe has one small interstage cap and one output transformer (and well designed SS amps sometimes have no reactive components) - we seem to be adding a lot of extra shit between the driver and output of a amp.
• The backloaded horn concept is interesting. This Madisound BK-16 kit does not need baffle correction (or any crossover components). Baffle correction is needed for speakers placed away from wall boundaries because higher frequencies bounce off the speaker baffle. The wider the baffle, the lower the frequency where the higher frequencies started to get augmented. In other words, baffle correction circuitry in the speaker lowers efficiency (it essentially is a treble shelf filter to push down the treble past a certain frequency.) The BK-16 takes the backwave (opposite phase signal) and pipes it through a transmission line/horn (tuned for bass and low mids). But the time the sound reaches the mouth of the horn, the signal is in phase with that of the driver. Hence, we are actually making the backwave of the driver contribute quite a lot (rather than have the energy of the backwave be absorbed in the stuffing materials or only partially using the energy of the backwave to augment low bass, as in a ported bass enclosure.)
• The BK-16 kit sounds good excellent at low volumes. Been staying up a night listening at low volumes (on the first floor - bedrooms are on second floor) and wondering WTF do headphones cost do much and how headphones are such a fricking waste... Don't be surprised if I cancel my Electra order and sell my Jades so I can get a Leviathan.

I have been very curious about the Fostex BK-16 for quite a while. It is a very decently price kit, and very well regarded. I'm even more curious now. I'm holding back quite a bit for several reasons, but those Fostex BK-16 seem like pure win. Sorry if my questions are too noobish but do these through a narrow sweet spot? paired with a sub (and perhaps super tweeters) would there be any problems in using these for home theater applications (perhaps 4 channel)?

The sweet spot was wider than anticipated. I think the single driver concept works well. The qualifier is that polar / power response of the BK-16 kit is horrible. The drivers, because of their size, beam high frequencies. The mouth of the horns play back bass to lower mid frequencies. But think of it as customized EQ. Move your head down for moar bass. Move your head up for less bass. Angle speakers outward for treble roll-off... LOL.

I would highly recommend for home theatre, but not a cinema simulator in your home. These are certainly not high SPL speakers - too much distortion for a 6" trying to carry such a wide-range. I think you would like it more with super tweeters. For me, it's on the edge. I could easily enjoy it without supertweeters; but I'm not that deaf, at least not yet, so I do plan on getting super tweeters. Maybe in 5 more years.

As far as subwoofer integration, the point of the the BK-16 is NOT to cross anything over or put any extraneous crap in the signal path so it maintains its "purity of tone" as much as possible. I would implement a subwoofer REL style:

• Let BK-16 do its thing and play full range without any crossovers in the way.
• Take a second set of outputs from the amp feeding the BK-16, pad those outputs to line-level, and input into a subwoofer x-over / amp. This really helps the sub integrate with the speakers.
• Cross the subwoofer over anywhere from 28-38Hz with a 12db/octave rolloff. With room gain, the sub should go up to 40-50Hz where it should meet up with the speakers

The supertweeter should be added with one cap in series. Some start the rolloff higher than 20kHz. 0.47uF for example.

BTW, for my living room (TV room) I plan on building the BK-16's little brother: http://www.madisoundspeakerstore.com/full-range-speaker-kits/fostex-bk-12m-folded-horn-kit-pair/


P.S.


BTW, come on over.
Luis came over this evening and was enamored with its sound. We should get a group buy for discount going.