Low freq. from small drivers? Is it possible

>Here is the frequency response of the Ultimate Monitor from >Karl Schuemann

The specs don't tell you enough to be useful.

1. They don't tell you about distortion. The mid-ranges used in my speakers are good for .3% THD @ 96dB/1 meter in their operating range with an increase to 1% at the tweeter cross over frequency where they're 6dB down and distortion should be less. Run at lower frequencies they'll have horrible distortion at much lower output levels - maybe 10% at 70dB one you reach 30Hz. This is especially bad at low frequencies where tight spacing of the equal loudness curves makes the harmonics sound louder than the fundamentals. IM distortion is even more of a problem.

2. They don't tell you what the maximum output level is at those frequencies. Using a pair of 6.5" scan speak mid-bass units (Sd = 145 cm^2, xmax = 5mm) in a sealed box the linear limits are about

88dB @ 35Hz
94dB @ 50Hz
100dB @ 71Hz

3. They don't tell you what the off-axis response looks like. At reasonable listening distances you're picking up more sound from the reverberant field than direct sound. The shape of the off-axis curves has a _huge_ effect on what you hear.

4. The don't quantify thermal compression. This is especially important where you start equalizing. The BOMB is a Linkwitz Transform which allows you to change the F3 point and Q of a speaker thus getting you lower bass extension and less group delay at higher frequencies. Low group delay means "fast bass." The problem is that your power requirements go up. The extra power increases voice coil heating and therefore resistance. That means more thermal compression and changes in the cross-over response with output level than you'd have in a speaker without equalization.

I'm sure the Ultimate Monitors are exceptional speakers although they can't break the laws of physics. If you want natural sounding bass at realistic output levels you need a 3-way or sub-woofers, the later being better because high and low frequency transducers interact with the room differently and therefore work best with different placement.

This question in analogous to asking whether it's possible to produce high horsepower from a small displacement piston engine. The answer is yes, but it's much easier, more efficient and less performance compromised if you produced the same horsepower with a larger displacement engine. Small cones in small cabinets can produce deep bass, but larger cones in larger cabinets can do it more easily. Multiple small cones in a large cabinet is a good combination, but it tends to be more expensive and complicated than an equivalent single large cone. Every design choice presents a set of compromises. None of the choices is inherently better than the others, they simply present a different set of compromises.

Onhwy61...A better analogy would be trying for high torque at low rpm from a small displacement engine. The small engine might produce lots of horsepower, but you won't win many drag races.

Drew,,,
I'm just curious as to any speaker which is in the same price range that lists all those specifications that you say are missing on the Karl Schuemann site.
I have been searching and Wilson Watt at $20K plus does not,
Sonus Faber Stradavari does not, Von Schweikert does not,
Kharma does not. In fact, Karl gives a huge amount of information of how his speakers spec and perform.

Before pointing fingers and saying that "The specs don't
tell you enough to be useful", do your homework please.

cheers,
Michael

Eldartford, what you describe is virtually impossible, whereas I recognize that you can get deep bass from relatively small cones.