[Dan G.]

Some companies such as ACI offer center channel speakers with additional mid-range units (as compared to their main speakers).
An example would be the ELT home theater package, in which the center is a 3-way design with not only an additional driver, but a completely different driver (a 2.5" mid) than the other speakers in the package.

Now, much has been written about the benefits of a seamless front stage by matching identical speakers and or drivers across the front.

I assume there are also benefits to this additional non-matching driver in the center (perhaps to avoid any crossovers) in the critical vocal range?

My questions are:
1. why this non-matching driver complement in the center channel
2. where are the XO points in such a speaker as the ELT or ACI's other center channel speakers
3. Why don't the main speakers/satellites utilize this same 3 way design if it performs well.
4. In general, what is the sonic impact of having this different driver/XO in the center.  

Thanks!
Dan G.

[Mike Dzurko]

Some companies such as ACI offer center channel speakers with additional mid-range units (as compared to their main speakers).
An example would be the ELT home theater package, in which the center is a 3-way design with not only an additional driver, but a completely different driver (a 2.5" mid) than the other speakers in the package.

Now, much has been written about the benefits of a seamless front stage by matching identical speakers and or drivers across the front.

I assume there are also benefit ...

Dan:

I need to leave for school. But I'll get back to your excellent questions later today. Quick note: We don't necessarily add any "additional" midrange drivers in the center. The Essence-Veritas centers use the same mid-tweeter array as the matching Essence-Veritas Vs, Panormas, and Talismans. This is pretty much like having three identical speakers across the front . . .

[Mike Dzurko]

Dan:

Okay, time for the more detailed answers to your questions. First and foremost, I believe that a vertically aligned mid-tweeter array is absolutely essential for a good center. The laying on the side MTMs are just a marketing compromise. The radiation pattern is all wrong.  I also feel that lateral dispersion in a center is very important as often the listeners will be off to one side or other. This mandates a midrange that is not too large. In the case of the Essence and Veritas, it is 5 1/4".

Our first center was and is the Emerald. Been in the line for around 10 years. It is a wonderful little vertical 5 1'4" two-way. Can people lay it on the side? Sure, but it is a compromise. Face it, our rooms and systems often force compromises. The Essence and Veritas centers came from the Emerald design. They use the same woofer as a mid-range and flank a pair of 6 1/2" woofers to the sides to cut in from 300Hz on down. This yields a design of nearly unlimited dynamic range.

The Essence/Veritas centers are designed to be absolutely seamless with their matching vertical versions, the Panormas and the Talismans. They all share the same mid-tweeter array.

The ELT design is something similar but different. We didn't design the ELT, so I have less to say about it. This I will say, it does an amazing job, and has the dispersion pattern that is what I want. The ELT sats don't really need the midrange because the bass-mid is small enough to do a good job in the midrange. Could the ELT sats have been designed as three-ways? Sure, but it would have added greatly to cost and size without as much sonic benefit.

A couple of general observations regarding centers. They don't have to sound identical to the mains. In fact, even if they do, the difference in placement is likely to change this. Try this. With a regular two channel setup, sit off to one side. Play pink noise alternating between your left and right speakers. It will sound different. Why? Because you are more directly on-axis with one than the other.  It is important that the center have as close a tonal match as possible to the mains OVER a wide listening window.

Thanks for asking the questions Dan!