Why I Love Single Driver Loudspeakers...
Musical recordings sound best when they are presented from a coherent point source - as only a single driver co-axial loudspeaker can provide
Only a single driver loudspeaker can deliver an ultra high level of sonic coherence and musical purity. On the surface, they are as simple as their name: one audio driver in a cabinet. Delve deeper and you'll find doing single-drivers right presents one of audio's most difficult design challenges.
Engineering a mechanical device that faithfully converts electronic signals into audible sound waves covering the FULL audio spectrum, without the aid of a crossover or multiple drivers sharing the work is a huge challenge.
Even a single musical note is comprised of a fundamental tone along with tones of higher pitch that are present in every musical sound. The presence of these overtones and harmonics determine the quality of the musical sound, and are in a large part why a guitar sounds like a guitar and an oboe sounds like an oboe. Introduction of a crossover (or filter) in a multi-way speaker means that one driver reproduces the fundamental tone, while a second driver reproduces portions of the harmonics and overtones. Yet somehow all these tones and overtones need to come back together to create a cohesive sound as close as possible to the original guitar or oboe.
Crossovers and Issues with Time & Phase Accuracy
Crossovers are considered by many to be a necessary evil. Their insertion in the signal path does nothing to improve the integrity or quality of the audio signal. Rather, they do quite the opposite. With single-drivers, there's no crossover or filter between the amp and your speakers, so the signal driving your music is as pure as you can get. There's also no need to have two or more drivers involved, even to reproduce just a single musical note!
Given enough money, a good speaker designer using a crossover and multiple drivers can do a good job of bringing fundamental notes and overtones back together. The challenge is to produce state of the art, involving, and realistic sounding music at affordable price points. Discrepancies in time and phase add to musical clutter, and diminish overall tone and coherency, which ultimately compromise sound quality. This means that regardless of price, once a crossover is introduced into the signal path, no speaker will ever be quite as coherent or open as a single driver design.
Single Driver Advantages
Quality crossovers and tweeters cost a lot of money. A single driver approach means you get higher quality because your entire investment is channeled into one driver and a quality cabinet. Passive crossovers also rob power and musicality from the signal, often by 10dB or more. This loss means you need a larger amp to achieve a given listening volume. It also means that drivers must be pushed harder to produce your music. With single driver speakers, the amplifier to speaker interface is far purer and the speakers feature 93dB to 95dB sensitivity. This means realistic listening levels can often be achieved with just a few watts of power. So, in a typical listening environment a single driver speaker and ordinary amplifier are barely being taxed at normal listening levels, and have plenty of headroom to reproduce powerful and uncluttered crescendos, or high volume listening levels when called to do so.
Single Driver Challenges
If a speaker designer is restricted to off-the-shelf drivers or standard cabinet alignments, they are severely handicapped when it comes to designing a well balanced and natural sounding single driver loudspeaker. As a result, the market includes products that perform less than optimal at upper frequencies or lower frequencies, and in some cases both ends of the frequency spectrum.
Some single driver loudspeakers have been criticized for exhibiting a forward, sometime even peaky-sounding midrange. Because a single driver speaker is the sum of it's parts, proper application of cabinet design, cabinet materials, speaker design, and speaker materials are a must to engineer out these problems. A solution from a manufacturer committed to a single driver design - preferably with in-house cabinets and proprietary full range drivers will stand out as best.
For more information, please contact: AudioWise Canada