In short, HDX is a little more refined than SDX and is our choice for critical listening. But let's compare the lines in more detail, starting first with how they are similar.
At a quick glance, many speaker brands may look alike, but it's our attention to design detail and build quality that sets HTD apart. Our SDX and HDX lines of in-wall and in-ceiling speakers demonstrate this philosophy. Note the smooth roll-off surrounding each moving driver - no sharp edges on the baffle means clearer audio; note the quality of components used on the crossover on the back of each speaker and the oversized magnets for faster response. Both lines are built for high power handling which means they will not distort at volume levels higher than most people will ever listen.
Unique to HTD, all of our in-wall and in-ceiling speakers come with two grille options that you can add after installation - choose from a completely trimless design that is held in place with neodymium magnets, or a grille that is firmly pressed into place revealing a modest trim similar to can lighting.
So how are they different?
Our SDX (Standard Definition) line of speakers offer great quality and produce a very nice sound, similar to speakers you might find at Best Buy only at a fraction of the cost because we sell our brand direct. We designed this line with polypropylene cones, a silk dome (not just a fabric "soft" dome) tweeter, and a nice crossover.
The SDX product line was primarily designed for general listening applications, such as whole house audio and background/ambient music. The SDX line is sometimes compared to the Polk RC series and includes a few additional features that Polk does not offer in this line. This includes a+/-3dB switch for the tweeter which allows the speaker to be slightly customized for your room or when matching the sound to other speakers in the room.
Our HDX (High Definition) line is more comparable to a custom-install brand, such as Niles or Speakercraft, and was designed more specifically for critical listening applications. This includes home theater/surround sound rooms and dedicated listening rooms. The HDX line includes aluminum woofers, anodized aluminum tweeters, and a 2nd order crossover. The lighter weight and stiffness of the aluminum drivers allows for a quicker, more accurate response. The tweeter provides all of the crispness of other high quality metal dome tweeters without ringing or harshness. The HDX line produces a cleaner, more detailed and more accurate reproduction of sound than the SDX line.
HDX speakers are also more flexible in their application. In addition to a +/-3dB switch on the tweeter, HDX also includes a +/-3dB switch on the woofer giving the listener even more flexibility for adjusting the tone to accommodate room anomalies or the listener's personal taste. With its aluminum components and powder coated grilles, the HDX line is also well-suited for high moisture environments, such as bathrooms and covered patios. As a result, we took the extra steps of gel-coating the electrical components on the crossovers and adding stainless steel mounting hardware to make them truly weather-resistant.
Both the HDX and SDX lines come ready for easy installation and can be painted to match any decor. All HTD speakers include a 30-day guarantee and 5-year warranty.