active speakers, Paradise? Trouble in paradise?

10K input impedance is accepted as the appropriate value. Generally a minimum of 10:1 contrast between input and output impedance is desired.

Raising the impedance well above 10K is not going to improve things - in fact it will likely result in greater sensitivity to micro-currents (ground loops, stay EMF etc.) which will make things worse in some situations. Although many active speakers use XLR balanced inputs and if these are well designed and properly balanced with respect to ground then ground loops and EMF/RF induced noise is already minimized significantly compared to RCA.

There are many extremely good manufacturers to choose from

ATC
PMC
Barefoot
Adam
Meridian
Genelec

They all vary a little in presntation - the first three are extremely dynamic, the last three are a bit smoother and warmer or more polished. All are outstanding if you get one of their top models and select according to your taste.

Yes the Event Opal raised many eyebrows when they came out. Lots of power. Great value - kind of a Genelec knock-off for about about 40% lower price.

IMHO though audiophiles will be most rewarded by getting into a three way active - like Adam Tensor, larger PMC's, larger ATC's or Barefoot MM27. Expensive unfortunately but impressive - hell yes!

I would add that far too many people have room acoustic issues and a high end active studio monitor is going to give them some grief. Unless you are prepared to go down the road of acoustic treatments to get the room closer to ideal then it is hardly worth getting a speaker that is as linear and as accurate as is technically possible with modern technology. One may be better served by getting some audio furniture (nice aesthetics) than investing in technology that clarifies all the warts in the recording and your room.

I’m having a hard time discerning any diffs from filters used in active x overs, and passive x overs… apart from this one thing.

An active line level crossover can use much steeper slopes than a passive kind. The line level signal is much less affected by the sonic characteristics of the capacitor used. The phase of the signal can also be adjusted optimally. There is no need for padding resistors to try to match the sensitivities of the drivers to the lowest common denominator (the least sensitive driver in the passive design). There are no awkward phase angles that may give an amplifier a tough load (high current demand due to complex low impedance).

There really is no contest. Active is just a far better way to skin the cat of distributing the audio signal between different transducers.

Marty,

Agreed. I was referring to the majority of conventional two ways. Omni's being a rather a minority.

Nearfield is indeed 2 to 6 feet. It is an important consideration in many designs as most two-way speakers run a 6 inch woofer up to 3 or 4KHZ. This makes them ONLY suitable for nearfield because already above 1KHz the woofer is starting to beam (i.e. changing from a floodlight dispersion pattern to a spot dispersion pattern). When you sit in the far field it is very important to have a speaker with even dispersion as the room reflections play a much bigger role in what your hear from the mid range and a "spot" presentation will not sound natural at all.

Very few nearfield designs have wide dispersion - you can check this very easily by looking at the X-over frequency. Any design with a X-over at 2 KHz or below (between mid/bass and tweeter) will ensure wide even dispersion.

More farfield designs have wide even dispersion but again you may want to check the X-over frequencies to be sure. (For example B&W make many farfield three way designs with a tweeter X-Over close to 4 KHz and this design will require careful messing around with toe-in/out to get the right mid range balance at the listener and even then the sweetspot on these designs is ALWAYS narrow because of the way upper mid range behaves like a spot light. A good flood light B&W design was their Silver Signature)

That pretty much settles it for me then.

Please note that my comments on nearfield two ways is not limited to active speakers at all.

Bob,

In order to disperse evenly and widelythe driver needs to be smaller in diameter than the wavelength of the sound being produced. In order to produce upper midrange frequencies at decent volumes (for farfield applications) it requires the use of a small but extremely robust (expensive) driver (a good size for upper midrange is 3 inch and as I have mentioned a 6 inch mid/bass is simply too large without beaming).

Less expensive to build speakers that beam

This is kind of a "dirty secret" among speaker makers - they know darn well what they are doing when they X-over a 1 inch tweeter with a 6 inch mid/bass woofer at 3 to 4 KHz. Basically they are compromising on sound quality at farfield positions in order to cheaply achieve teh necessary SPL levels (as most 1" tweeters can't cope with the needed SPL levels at 2 KHz).

Marty,

The Ohm design deserves a whole discussion in itself. I do not believe that they are immune from the laws of physics - and a large radiating surface is still going to beam - but by changing the orientation of the cone the beaming will occur towards the ceiling and in the direction of the cone movement (which still yields a reduced dispersion in the horizontal plane at higher frequencies)

My Genelec 8020B have a 4 inch mid/woofer and are crossed over at 3 KHz.

The dispersion is nice and even but the woofer is small and Genelec provide plots (which you can find on line)

Digital EQ is wonderful and there is a huge amount of hype and marketing for auto-EQ equipment (hook up a microphone and press a button and presto your sound is "optimized") but it is important to recognize the limitations. First and foremost it is always better to improve room acoustics, speaker and listening positions. After as much acceptable acoustic improvements have been made then it falls to EQ (with digital EQ being the most flexible). Below 100 Hz the wavelengths are 10 feet or longer. These frequencies are a reasonable target for notch filtering as you can remove nasty room modal resonant peaks and have an effect on nearly the entire room because the wavelengths are long enough.

Above 100 Hz my recommendation is not to use any sharp EQ. I am fully on board with any broad treble of bass tilt adjustments to suit your tastes and room general issues but nothing else (for example a room with a tile floor will probably be too bright unless you turn down the treble a wee bit)! The issue is that at 1000 Hz you have wavelengths of the order of 1 foot - this means that you have a peak and a trough of a sound wave over a distance of a mere 6 inches. This makes it impractical to have any meaningful effect on the room at all (the benefit may be fine for one microphone position but detrimental for another). All you can do is correct a little for problems with the recording itself or the equipment itself (and, as with the room, it is first and foremost better to get equipment that works for you without needing tweaks)

In any case room EQ is an important topic but a separate issue from active vs passive speakers as it can be applied to both.

As Doug and several others have mentioned - ridding yourself of the passive X-over and the limitations of passive filtering of high power signals is perhaps the biggest advantage of "active". For the same reasons that single driver speakers sound so lively and clear (but have limited frequency response), active speakers (or at least well designed ones) all share a lively dynamic sound as if a veil has been removed. I believe this is because of the removal of the crossover. Passive crossovers rob some life from the music over quite a wide region - up to a couple of octaves. These passive crossover issues have manifested themselves in the need for massive monoblock amplifiers to breathe life back into the music. (If we look at Active speakers then we find the amplifiers are rather modest in size for the equivalent power output)

Focal Twin 6 are another active design that are extremely good & very popular - I agree that they would be very good as a home stereo and would make a great surround setup too.