Originally Posted by MKtheater
I know we have discussed this before, but we really never figured out why. I want to know what the HE(specific ones) lack that the soundscapes or B&W, or whatever has. See, I believe one does not need to settle, they can have both.
I'll take a shot at this. There are considerations other than frequency domain performance when evaluating a speaker system.
The great majority of HE speakers use compression drivers for the mids and highs while typical direct radiators use some combination of cones, domes, planars/ribbons and ring radiators.
This is from the Pi Speakers Whitepaper (which I found very interesting and informative) that zheka likes to reference:
"An important requirement for the constant directivity crossover is top-octave compensation. As seen earlier, the power response of a compression driver falls off at 6dB/octave above mass-rolloff. In a typical 1” exit compression driver, this starts around 4kHz, so top-octave compensation generally adds about 12dB boost total."
What this tells me is that the typical compression driver will have poor spectral decay performance because of its high mass. A ribbon on the other hand is intrinsically low mass and will have far superior performance in this area:http://www.alconsaudio.com/site/cinema/pro-ribbon-vs-compression-driver.html
The waterfall plot of the Raal RAAL 70-20XR (along with a good dome) is shown about half way into this document on its use in the Ascend Sierra Tower:http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend%20Sierra%20Ribbon%20Tower.pdf
I could be wrong, but I believe spectral decay performance is a major factor why certain people prefer direct radiator designs vice HE designs. On average, their performance in this area is just better. You can listen at lower levels and still feel like you are not missing information. CD performance in this area may be improved by using extremely light and strong diaphragm materials (e.g. beryllium) but the cost becomes prohibitive unless the speaker is designed to a high price point. For example, I believe a TAD CD of this type goes for $2K for a single driver.
In addition, the CD in the great majority of cases is horn/waveguide loaded. I won't go into this subject except to say that the direct radiator adherents may also be basing their dislike of HE designs on hearing ones with poor horn/waveguide design. Wayne Parnham's paper does a good job of explaining why certain horn geometries sound the way they do. If you believe Earl Geddes, an oblate spheroid geometry and open cell foam placed in the mouth are required to achieve the best waveguide performance. Also, if a speaker uses a conventional horn design, the drivers will usually not be time aligned without the use of an active crossover (Danley's Synergy Horns excepted). This will distort the image somewhat especially in a folded horn design.
Every designer makes tradeoffs based on the requirements for the market segment and price point that he is targeting. Most HE designs are targeted for, or have their genesis from, professional sound reinforcement which imposes a set of requirements that a design must meet to function in that environment (high efficiency, high power handling, rugged construction). The home use market segment imposes a different set of requirements (low level clarity, imaging, aesthetics). The tradeoffs that a designer makes will be different in these markets.
Ultimately, each individual customer has his/her own set of threshold and objective requirements for an audio system. Any system that does not meet the threshold requirements will not make the cut. An example of this is that one person may enjoy movies with lots of special effects and be in the market for a HT theater system that can play at reference level or beyond. Any speaker that cannot meet this threshold requirement is rejected out of hand. Another person may be looking for a system for both HT and music, loves film scores and watches the majority of his movies with his spouse. This person's threshold requirement might be the ability to provide a satisfying listening experience at lower volumes.
The customer then rates the systems that meet the threshold requirements against the his/her objective requirements. The customer weights these objective requirements based on his/her sonic value system. This process will almost always be informal. A better approach would be to formalize the process and apply numerical weightings to these requirements and then score a system's ability to approach or exceed the objective requirements (i.e. perform a trade study).
So the statement that a good speaker is a good speaker for all applications is simply not true in a lot of cases. Using an extreme example, a formula 1 design and a top fuel dragster design may both be top performers, but they each would be completely inadequate in the other's domain.
In the end, what each person values sonically is different and will result in different system choices. If a person's system meets or exceeds their requirements and brings them enjoyment, more power to 'em.