Why Do Most Designs Favor 'Cheaper' Tweeters

[2MuchRiceMakesMeSick]

After looking at many designs it has become apparent that many favor 'cheaper' tweeters then the mid, or mid bass. This is seems backwards since the tweeter covers most of the spectrum (~4k to 20k).

Here is just a few of many examples
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In car audio, usually the cheaper tweeters are awful sounding. So why not use higher range tweeters?

[Cal Weldon]

Remember or look up what octaves are before you say most of the spectrum.
Most music is between 100 Hz and 4Khz.
The midrange is the critical part as your ear is most sensitive to realism, or lack of, in that area.

[speaker dave]

And a lot of cheap tweeters perform quite well.

I look for two things in a tweeter: smooth top end, and clean low distortion sound when swept down towards resonance. The first you will see in published response curves. The second you can easily hear by ear.

After those two items, much of the sound of a tweeter is down to the mounting of it. If you flush it in smoothly to a cabinet with clean edges and no reflective surfaces, then a cheap tweeter can sound quite good.

More tweeters have their performance messed up by bad mounting than bad design.

David S.

[planet10]

Originally Posted by 2MuchRiceMakesMeSick

since the tweeter covers most of the spectrum (~4k to 20k).

This premise is incorrect. When we talk of frequency range, because of how we hear, we need to talk in octaves, a logarithmic scale.

4-20k is just over 2 octaves, leaving just under 8 octaves (20-4k) left to cover, althou in most cases even 7 octaves (40-4k) would be a good goal for a 2-way.

If one considers the typical distribution of energy in the music, 300 Hz is about the 1/2 way point, and a very suitable place to XO.

dave

[AndrewT]

Part of the cheap tweeter philosophy may have to do with the assumption that the tweeters only have to handle very low power and thus need only a small proportion of the resources.

[rob g]

Part of it is down to how you use them.
In a typical passive design the loudspeaker designer will cross the tweeter over at around 2.5-3khz. Plenty of more affordable tweeters cope with that well enough, even if they can be bettered.

With some of the more exotic designs like the Linkwitz Orion the designer has gone for a low crossover point. This requires a really well behaved tweeter, the majority of tweeters that can cope with this are pretty expensive.

It is the law of diminishing returns in many cases. The benefits of expensive tweeters against the best mid price or even budget designs are relatively small.

Music lives in the midrange but you shouldn't mess that up with harsh lower treble.

[DDF]

Originally Posted by speaker dave

And a lot of cheap tweeters perform quite well.

I look for two things in a tweeter: smooth top end, and clean low distortion sound when swept down towards resonance. The first you will see in published response curves. The second you can easily hear by ear.

After those two items, much of the sound of a tweeter is down to the mounting of it. If you flush it in smoothly to a cabinet with clean edges and no reflective surfaces, then a cheap tweeter can sound quite good.

More tweeters have their performance messed up by bad mounting than bad design.

David S.

I think alot of it also comes down to dispersion in the top octaves as well. The D26NC is the shockingly best tweeter I have ever measured on axis taken as a whole (distortion and response flatness) but it had a very limited dispersion in the top end, and to me sounds a bit overly "dead".

[DrDyna]

I've fallen in love with the B&G Neo 3 PDR lately, I suppose on the grand scheme of things it's not especially expensive.

There are some exceptional tweeters, like the Heil AMT that are worth every cent of their chunky price tag, but I've found that most of the tweeters I like are in the 60-80 dollar range.

[gedlee]

IMO it is the defacto standard 1" dome tweeter that is the limiting factor in most loudspeakers. While it may only cover a "few" octaves, these are the critical octaves in that this is where nature has made our hearing most accute. It turns out that getting beyond the "1" tweeter standard " moves the design into a whole new realm that gets complex and expensive. So quite simply the "standard" is inexpensive, easy to use and "acceptable" for most. But it is, as I said, the factor that limits performance. Every 1" dome speaker that I listen to has that same "something is missing" or "TOOOO much!" sound quality.

But I agree with Dave, mounting is usually done wrong and makes a big difference.

[Conrad Hoffman]

So Earl, I'm curious, what do you think of Morel MDT-28s? Too much or too much missing? I used to use Peerless but feel they come up short in too many areas. I've got some Dynaudio D-28s that will go into an MTM with some Focals, assuming I ever get around to it. Thoughts?