Whistle blowing.(multi-channel speakers)

It seems that the entertainment industry is more interested in selling you a multi-channel speaker system than they are in divulging details about how center channel speakers actually work. Practically all modern center channels use the popular MTM topology (mid-tweeter-mid) with a pair of woofers flanking a tweeter in a horizontal array using a short, wide cabinet that looks 'right' when sitting atop a large screen television.

One larger manufacturer's website, for example, points out that its center-channel speakers use the same drivers as its main LR speakers, and implies that this will make for good matching. While there's nothing outrightly "deceptive" about this text, it should be noted that most of this manufacturer's dedicated center-channel speakers uses a horizontally arrayed MTM layout. Not just some, but most of them.

So what? Well the hidden story here is that the popular horizontally arrayed MTM (mid-tweeter-mid) center channel speaker has a certain performance deficiency that the manufacturer doesn't mention. Drivers in any multi-way system which are located side-by-side exhibit different horizontal and vertical off-axis lobing near their crossover point where both are contributing to overall sound pressure.

Most multi-way speakers are vertically arrayed (tweeter above or below the midrange) because this crossover area lobing then occurs in the vertical plane (up and down) instead of being radiated horizontally into your listening area. indeed the "D'Appolito" array, a vertical MTM, was originally developed to improve directivity in the horizontal plane.

This manufacturer doesn't mention directivity at all in his write-up. There is no discussion of multiple listeners, no mention that off-axis signals in the horizontal plane are important too, no mention that timbre differences are audible noticeable off-axis when an MTM speaker is rotated between vertical and horizontal radiation, no mention that one of their good sounding small vertically aligned 2-way models would probably work as well (or better) ... and probably may also use the same drivers as the center channel.

I fully understand that sales are important and that good sales floor and customer training is an important part of good business practice and that most manufacturers are held hostage by what the "competition does." But I also think that suppression of the operating characteristics of horizontally arrayed MTM center channel speakers, is an industry embarrassment. Furthermore it seems to be intentional.

Even those manufacturers with high performance center channels don't boast about their speakers or even call attention to them in respect to directivity. Perhaps that's because most of those companies also sell horizontally arrayed center speakers.