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I agree, the vast majority of audiophiles choose passive xo, because it's good enough for them. But there is more to be had with active/DSP, so its pursuit is valid, imo.
I've had many great sounding combos with passive speakers and an amplifier, yet at least in the budget realm, quite a few people think for $300 the JBL LSR305 sounds much better than $200 passive speakers and a $100 amp, so maybe for those non-critical budget applications it makes more sense?Steve
Elac website says they will be available July 5.
Another argument for two channel! I'm all for the simplest solution. Life's too short for surround!
Perhaps the next wave of innovation will be in the area of driver design. If you can design both drivers in a 2 way so that the FR is very flat and one driver naturally rolls off as the other one naturally comes in then you wouldn't need any crossover at all and the SQ wouldn't be hurt by passive or active components. You could physically line up the voice coils to control phase issues. It would be optimum if both drivers were of equal efficiency. Waveguides could help with directivity in the upper frequency region.
But with that scenario, the energy to their voice coils that was outside the desired passband would be heating the coils and needlessly lowering the thermal compression threshold. This would apply particularly to the mid and high drivers in a three way and the high driver in a two way. You really don't want to be sending all that energy to a high driver, even if it isn't responding audibly (to the unwanted low frequencies).
Yeah, but wouldn't this be like two single drivers integrated into one system. Bass/midbass driver would be designed for, let's say 60hz > 650hz rolling off gradually. Treble driver 750hz >18000hz. Just run them free range. I don't understand how the voice coils would heat up in this design.
Considering the treble unit only, if it was being fed full bandwidth, but reproducing only from 750Hz up, where does that energy from 20Hz to 750Hz go? It's wasted as heat in the voice coil and contributing to too-early thermal compression due to the rising resistance in the voice coil due to that heat. Not such a big deal in a bass/mid driver, although the characteristic that would lead to a 650Hz rolloff are in conflict with what is needed for fast transient response times. Then you have the myriad problems associated with low order crossovers, even without the crossovers, such as the need to be precisely aligned in the vertical axis of dispersion in order to hear the intended frequency response, due to both drivers being so active over the few octaves they have in common, etc.The only current examples of successful designs like this involve a very well behaved widerange driver running free with a tweeter supplementing the highest octave or two only, but crossed over—except for the French (those French!) PHY http://www.phy-hp.com/ which utilize a piezoelectric tweeter as an HF unit. Piezzos are naturally bandwidth limited by nature and *can* be used without any crossover—but even they can benefit:http://www.frugal-phile.com/piezo-XO.html
Ah I see. How about if you over engineer and have a voice coil that can handle the heat?
Yeah, but wouldn't this be like two single drivers integrated into one speaker. Bass/midbass driver would be designed for, let's say 60hz > 650hz rolling off gradually. Treble driver 750hz >18000hz. Just run them free range. I don't understand how the voice coils would heat up in this design. No crossover parts whatsoever. Bi amp them.
Sorry, my reference to the DCX may have confused things. My DCX will be used solely to control the subs. The only DAC in the signal path to my mains is my Auralic Vega. I had been trying not sidetrack the thread's discussion of active speakers in general by detailing my personal system, but...To start with, my music is stored on a NAS which connects to a Mac Mini via Ethernet. On the Mac Mini, I run Roon for music browsing and HQPlayer to apply the driver EQ correction and upsample to the native sampling rate of my DAC. The HQPlayer-processed digital output is fed by the Mac Mini to my DAC over USB. The analog output of my DAC is then sent to my Bent TAP-X passive pre-amp, which has two simultaneously driven outputs. One pre-amp output is sent to the active gain-stage equipped, analog, line-level crossover (a Pass XVR-1), then the Pass XA30.5 amps, and finally to my 2-way speakers. When I get my subwoofers finished, the second output of the pre-amp will route to the DCX, which will then control the full array of subwoofers.So yes, the DCX imposes an extra ADC/DAC, but only to the subwoofer signal path, not the mains.A few misc notes...The mains path is fully differential from end to end. The subwoofer path is fully differential except for the DCX, which is impedance balanced, but not truly differential.HQPlayer's unique polysinc reconstruction filters are viewed by many to be superior to those found in almost any DAC, thus the choice to upsample to the DAC's native DSD128 sampling rate on the Mac rather than rely on the DAC's reconstruction filter to do it. (HQPlayer is also the only software or hardware that I know of that can apply EQ correction to a DSD audio stream.)To clarify for the sake of multiple other posts, an active speaker system is one that has the cross-over implemented before the amplification stages, when the signal voltage is at line-level. A passive speaker system has the crossover implemented after the amplification stages, when the signal voltage is at speaker-level. The active/passive distinction does not depend on whether the line-level crossover is digital or analog, or whether the amplification is internal or external to the speaker.Again, it's unfortunate that "active" is used in audio both to distinguish between powered vs. unpowered components (or more precisely the presence of a powered gain stage), and systems using line-level vs speaker-level crossovers. For example, there are many "powered monitors" out there that are not "active" in the sense of having a line-level crossover.... they simply have a built-in amp that still feeds an internal speaker level crossover.Hope that helps.We now return to lusting after Josh's JBL M2s... oh wait, I mean Andrew Jones's discussion of active speaker benefits!
