Question concerning db sensitivity

Assuming equal box size, the less efficient speaker will usually have deeper bass, or better bass transient response, or some combination thereof.

Peaks in the frequency response are more audible than dips, and the process of smoothing out a driver's frequency response by bringing down the peaks via equalzation in the crossover network inherently lowers the system's efficiency.

Cones that are heaviliy damped tend to sound smoother than lighter, less well damped cones. The heavier cones usually sound smoother, but may also sound less lively and detailed - so it's often a trade-off.

I would disagree with this statement: "In general, the higher the db sensitivity of a given speaker, the more you sacrifice in terms of sound." It's more complicated than that. There are trade-offs made either way, and which is the most desirable set of trade-offs depends on the specific application as well as - gasp - individual preference.

I believe that there are fairly large variations from one person to another in our tolerance for different types distortion, so you might not be bothered by the midrange forwardness that is driving me nuts while I'm oblivious to the power compression that ruins it for you.

Duke

Jmcgrogan2 wrote: "Generally, there are no generalizations in the audio hobby."

LOL! That's great! I presume you did that on purpose.

There's a great deal of truth in that statement. One can find exceptions to most of the generalizations (and if I'd have said "to all of the generalizations", I'd have been over-generalizing!).

It is the high efficiency speakers that are smooth that are the most exciting. It is the low efficiency speakers with great dynamics that are most exciting. It is the box speakers that sound boxless, the horn speakers that sound hornless, and the planar speakers that can do deep bass and don't beam that are the most exciting. Seek out the innovative exceptions - they're out there!

Duke

Nearfield monitors are typically not prosound equivalents of high-end speakers. Natural sound is not necessarily a high priority for a nearfield monitor.

Main monitors on the other hand do place a high emphasis on sound quality. While it's true many studios use B&W or ATC speakers (the ATC midrange is short-horn loaded), TAD monitors are still in use in many studios. Genelecs use waveguides, which are a type of horn.

Horn loading of some type is more common than you may realize.

The coaxial units in speakers by Gradient, Tannoy, KEF, Pioneer (Model One, S-1EX and S-2EX), and others use the midbass driver's cone as a horn or waveguide for the tweeter. I'm presently learning more about this format, and have a coaxial-based speaker or two under development.

In many cases, the device or cabinet feature called a "waveguide" could just as well be called a "wide-pattern conical horn". Examples of such waveguide speakers include models by Amphion, Genelec, YGA, GedLee, SP Technology, Emerald Physics, and yours truly.

Finally, many modern horns are very low in coloration compared with earlier generation horns. Tractrix, hyperbolic, Le Cleac'h, oblate spherioid, bispherioidal, elliptical, quadratic, whatever the Oris is - these are some examples. Johnk, do you know what type of profile the Oris uses?

Once upon a time I administered a blind listening test involving a modern horn-type speaker. One of the listeners owned electrostats. In his notes, this listener commented that he suspected the speaker was an electrostat. I have demonstrated modern "waveguide" (wide-pattern conical horn) designs to literally hundreds of people, and not one has commented that he or she heard any cupped-hands or other horn-like colorations, and often I've specifically asked.

Duke

Shadorne,

Very interesting site, thanks for the link. I've used that ATC midrange driver and agree that it is a very high quality unit. It doesn't really fit in with my present speaker design paradigm so I'm not using it any longer, but in my opinion its among the very best direct-radiator moving coil midranges in production today.

The article points out something that's often overlooked regarding the fabled ATC dome midrange - once it has been equalized, its efficiency is down to about 90 dB.

The article on waveguides is also quite informative. A large-radius lip at the mouth is indeed desireable, and any round horn or waveguide will have on-axis anomalies (in particular a hole) that's related to the dimensions, lip radius, and microphone distance. Whether the on-axis anomalies are audible depends on several factors, but I prefer to sidestep the issue by listening off axis.

I like a narrower pattern than what the author recommends. He seems to like 110 to 150 degrees, presumably in pursuit of a wide sweet spot. In my experience a 90 degree pattern will give you a very wide sweet spot provided you use a lot of toe-in, and also there is less pattern-width discrepancy in the top end when the tweeter does start to become directional.

The author takes the position that a direct radiator is superior to a compression driver because it has smoother response. I'll concede that its easier to get smooth-sounding response from a waveguide-loaded direct radiator, but it can be done with a compression driver as well (the ear is insentitive to narrow-band peaks and dips as long as they average out over a fairly short interval). And the compression driver will almost always have higher efficiency and better dynamic characteristics, which may or may not be desirable in a particular applicaiton (you don't want a big mismatch in power compression charactersitics between the woofer and tweeter). Having built prototype systems using both approaches I prefer the compression driver, but suitable ones are rare and even then they aren't easy to work with.

One of these days I'd like to see how a two-way with waveguide-loaded tweeter compares side-by-side with something like an ATC SCM-50.

Duke