Originally Posted by lemonslush
They are running off your AV at the moment I assume?
I wonder how many more DB powering one with a DSI amp vs using the same wattage and going through a crossover. My guess is you would be getting a tad advantage with the woofers driving the amp
s and the CD
. Using the crossover it would need to split that signal and you would be loosing output in the process.
That said could you actually hear a difference? I wonder.
This AV stuff is hard to quantify I think. Subs are easy as you add more subs..it gets louder.(more db) but with speakers if your going from one efficient speaker to another. My hears have a hard time telling if ones better than the other. It may be a tad bit cleaner when pushed harder on one vs the other but for normal listening do you notice a difference? Maybe going from something like my klipsch to the 4722 with those dual 15" you would notice it.
What did you have previously JTR'S?
It's more complicated than that.
First- the damping factor and the latency is improved on the active design because the signal does not need to go through a crossover and there is less resistance as a result- this also allows a more direct amplifier to driver connection and provides a better damping factor. This is particularly important on class D amps, since one of their weaknesses is usually in this area especially with passive speakers or speakers that have a changing impedance and full range signal. The active amps work a little better driving a single driver direct, than they do driving a system of passive. This is one of the inherent advantages of active set ups.
Second - With active you get a serious bonus when pushing them hard. Something to consider is if one of the amps or channels is being driven into clipping, that clipping is confined to it's own band. Usually it's bass peaks and lower frequencies that cause this, and clipping is usually less audible in the bass frequencies and regions. That means if you start driving it hard and your woofers are clipping, your tweeter is not. So it still sounds clean for the most part. So you don't get the negative effect clipping has as much, or as early with an active system. I read on here or somewhere that active systems can be run 4db louder for the same subjective impairment compared to passive. This is equivalent to more than twice the power BTW. So dumping 800 watts to active (easily done) is like dumping 1600+ watts to passive so you get a little extra headroom, or better performance near the limits.
Third- Another cool thing from a design perspective is drivers of different sensitivities can be used. So basically the tweeter is never going to clip on the active off an amp that big because it's never going to get anywhere near the limitations of the amplifier. And the tweet being 8 ohms and pulling less power, while the woofers being 4 ohms and pulling more power- just makes sense really. It works well together in the active set up- but in the passive you'd want to consider the total impedance load of the speaker so you have less design choices or make more compromises.
Fourth- there is some really advanced stuff JBL does in the presets. There is a lot of EQ, shelf filters, delay, DSP, different kinds of crossovers, and such things available in those amps. That's why the settings are different for the active than they are the passive. The same speaker- for example 4722- does not use the same crossover or settings in the active as it does in the passive network. Neither is a carbon clone of the other. Considering there is more available with the active, I am assuming that's the one that most optimized, with the passive being a little more of a compromise due to the practical limitation of it's design. Most of the JBL presets seems to have EQ at certain bands, with vary levels of Q and boost, which I am assuming is to get them more flat. They also have specific delay settings, and in a lot of cases the crossover is a totally different slope, or centered at a different frequency. Considering the lengths JBL PRO goes through in designing and testing their products I have to believe these things are not random, or an accident. They are most likely deliberate to get the most performance possible, or provide the most accurate response.
Personally I'd probably end up with both the passive network (external) and the active and A/B them if I bought these speakers because for the small cost of the crossover it seems like it would be interesting and worth it just to compare. But my gut tells me the active has some small advantages because at least in theory it does to start out, and if I reverse engineer the designs it kind of jumps out that JBL PRO took full advantage of the powerful DSP in the DSi amps and did some specific things, which I believe was deliberate.