Guest Contribution — True Sound: Full-Range or Crossover?

by Audiophilia on January 23, 2014 · 5 comments

in Loudspeakers

Jack Stokes enjoys writing about the finer points of speakers and will never pass up the chance to debate the merits of different designs. Having grown up in apartments, he could never enjoy his music without his neighbours complaining and had to move to the country in order enjoy it the way he likes it most: loud.

The Basics:

The method of producing true sound has been debated since the genesis of hi-fi speakers. Each company and party claims to have the best combination of materials and technology for producing the most accurate representation of the music. However, both sides do have their merits and downsides. In order to establish a baseline of terms and concepts, I want to address the basic terms and ideas behind full-range and crossover speakers.

Full-Range:

The typical computer speaker bought from a box store today tout “full-range” drivers, but in the world of hi-fi these are paltry claims similar to saying house cat and a tiger are the same thing: a cat. When I say “Full-Range” I’m talking about one speaker driver delivering the full range of sound, ~60Hz to ~8 kHz, with as little distortion as possible.

The only exception to this would be the inclusion of a super tweeter to handle the frequencies above 8 kHz such as cymbals or flutes; more for adding that extra sparkle to the music rather than a main component.

Crossover:

To keep things more simple when discussing crossover, I will be referencing passive crossover, we could go into active, digital, and mechanical, but that would become a book. Passive crossover speakers typically have the components built into the cabinet and are frequency and impedance specific. These inductors and capacitors limit the frequencies going to each speaker (Limits high frequencies to the sub and low frequencies to the tweeter) protecting them from being overloaded.

The idea behind passive crossover is to ensure that each speaker is only responsible for the frequencies it can handle the best.

The Comparison:

Both methods of producing sound are vying for the same goal: true sound (producing music as close as possible to the original sound). Full-range advocates will decry crossover as an unnecessary “fixing” of the sound. The parsing of the frequencies into individual speakers creates a black and white environment; eliminating the grey area where mid-range meets tweeter and subwoofer meets mid. In an attempt to fix this, there have been 4 orders of crossover created to better control the frequencies handled by each speaker and “stitching” the speakers together.

However, just like skin, two speakers cannot be stitched together perfectly without leaving a scar in the sound. The control that a fourth order crossover gives the user can reduce the scar; however achieving critical alignment is rarely achieved. The goal of crossover is to accurately represent the frequency with the correct tool and limit the amount of distortion by “closing” the sound and reducing the coloring of the music by the speaker.

Full-range drivers take an almost opposite approach to producing true sound. One full range driver delivers the sound without parsing the sound into different frequency ranges. Whereas crossovers create a black and white environment, full range speakers can be considered grey.

They seamlessly produce the full range of frequencies and reduce the coloring of the music through cabinet design and cone material. In order to achieve the appropriate timing for each wavelength, full-range speakers typically have to be placed in the cabinet and also in the room appropriately. This is a fine-tuning operation, but requires less effort and expertise than a fourth order crossover.

Verdict:

I’m a big fan of full-range drivers with the tweeter addition for that extra sparkle. I own a pair of Zu Druid Loudspeakers and wouldn’t trade them in for the world. Some would argue that this is technically a crossover since there is an acoustic crossing point between the super tweeter and full-range driver, but I would argue that it’s an attribute, not a function of the technology within the speaker. I think the most accurate representation of music is produced when there are a minimal amount of processes the current has to go through before reaching the driver.

Crossovers parse it too much and create unneeded complications when getting up in the third or fourth orders without ensuring that the additional control will replicate clearer music. The crossover points suited for our ears aren’t the best points for the speakers so implementing them in the ranges we can hear, distorts the music and when you try to reduce these points of interruption, more speakers have to be added to the setup further increasing the cost of the setup. Finally, crossovers, especially passive crossovers, require extra power reducing the efficiency of the speakers and contribute to distortion at high levels of power.

{ 5 comments… read them below or add one }

admin 01.23.14 at 2:35 pm

Thanks for the to-the-point guest contribution, Jack. Much appreciated.

I’ve heard Zu products during some recent shows. I count myself as a fan. And, for the price point, there’s not much better.

Cheers, Anthony

admin 01.23.14 at 2:39 pm

If one approaches the mysterium that are crossovers as pure science, trouble can follow. The best crossovers I’ve ‘never’ heard are tuned by engineers with great ears and/or a great team.

Cheers, a

Gary 01.24.14 at 5:00 pm

I own a pair of Zu Definition 4s (I have never heard the Druids), and I echo your comments.

Michael Levy 01.27.14 at 11:59 am

Designing a speaker strictly by a particular theoretical approach, I have found, is like planning everything you will do and see on a foreign vacation, to a country you have never seen, from home. You will get a very limited view.
I have been designing speakers professionally since 1980, and the process never fails to teach me a lesson every time I design a new product. In this case, I hate to say, my experience and theory say that you may have missed the mark. If you want to understand a little of my design philosophy, there are a series of articles in the Audiophilia archives under the name “Designing an Audiophile Loudspeaker” I stopped writing the articles when the next one was to be titled, “listening”. In the articles I did state that theory would like a design that is as close being one full range driver as possible, and listening mostly confirmed that statement. But listening and theory show that the drivers should be well withing a wavelength at their crossover frequency in their center to center distance in order to minimize interference patterns in the output. Also, there is the Doppler distortion that is incurred when a driver is too full range. The crossover itself must be tuned using both the finest equipment and the best ears because no driver has a linear impedance, frequency response, or phase curve. In the end it was listening that required the most work for my new design, and resulted in the most important innovations. It was listening that finally chose the drivers, the crossover shape and frequency, and the cabinet tuning. They are presently in beta testing. Marty Appel’s latest reviews in Audiophilia were made using them as his reference. I will be putting on a few more beta testers before releasing the final product for sale and review. At which point, Anthony has requested a pair.

Jack Stokes 01.27.14 at 3:47 pm

Anthony, I appreciate the opportunity to write for Audiophilia. I do agree with your point, the best crossovers are ‘never’ heard; it’s getting to that point that is difficult.

Michael, I really appreciate your in-depth comment. I can’t say I have as much experience as you do and I really enjoyed reading your the part series that you mentioned. I’m curious, how much reduction to interference patterns and Doppler distortion can you attribute to cabinet design and/or crossover? Would a full-range driver with excellent cabinet design perform better than a crossover with less optimized cabinet design?

As I read through your comment, I agree that I may have missed the mark a little bit. The idea of one theory being ‘better’ than the other is misleading. Like you said in your comment, “It was listening that finally chose the drivers…”, and listening is a purely subjective measurement. I really enjoy the debate and innovation in loudspeakers that comes from the healthy (healthy in my mind) competition/debate between crossover and full-range designs. I think it can be considered like chocolate, some people prefer milk chocolate, others dark, but they are both representations of the same idea ‘chocolate’ presented in different manners.

Leave a Comment

You can use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>