Question concerning db sensitivity

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

Johnk,

Horns are used in studios.....usualy on the wall a set of compresion horns with BR bass will be in use.

I agree the horns are almost exclusively used for main monitors which are mainly used to impress clients at high SPL's.

I was trying to say that most nearfields for mixing and mastering do not use horns and that even for main monitors(the big soffit mounted beasts) there has been a significant shift away from horns ( a process that only begain in the 70's). Older studios may still have horns in place. Horns have not been entirely displaced from the studio.

Duke oris is tactrix, your right about wave guides I see many monitors using shallow guides. The only time I heard the cuped hand sound is from a old edison theater horn that I installed a 2in driver in sounds fun loud very very directional but does have the cupped hand sound but its a primitive horn designed to make the most out of edison cylinders.Not hifi just so folks in back could hear the talkies.Could these myths about modern horn sound come from so long ago? I just dont hear this honk, cupped hands etc that folks say modern horns produce and since I have built and tried so many types designs transducers think I would of run into it;)

Duke,

Good point. Waveguide loaded mid ranges and tweeters are widely used everywhere even in nearfields. I draw a large distinction between these designs and traditional "compression" horns ....but like most things in this hobby many designs share some physical similarities.

Here is a good independent article on this subject (Ralph at AERONet). Waveguide Mid range Design

There are more details and a discussion of waveguide versus compression horns on this website (for those seriously interested...I realize details can tend to make most people's eyes glaze over in a hobby which is largely intended to be just a fun pastime).

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