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Aiming Component Speakers

Aiming Component Speakers

What is a real example of consulting with me about mobile audio systems? I spoke with a gentleman today about his sound system plans regarding a set of Focal Utopia No.7 3-way components. He had questions.

Where to install and aim the mid-range speakers and tweeters?

Is my head unit, a Sony RSX-GS9 with time alignment, as good as a separate DSP?

My follow-up e-mail, with some emphasis for SEO and clarity in your browser:

If you can’t play it loudly, well-balanced, for a long time reliably then what’s the point?

Aiming Component Speakers

Mid and tweeter placement and aiming in a 3-way active configuration:
– When we have full control over the High Pass and Low Pass filters, meaning both the crossing frequency and the slope, there is no need to aim the midbass woofer or the mid-range speaker. Our guide is the following chart:

Loudspeaker Dispersion Chart

Looking at the half-circle diagrams from left to right, this is showing the relationship between the wavelength of sound at a particular frequency in relation to the diameter of the speaker cone.

Green = sound spreading as widely as possible away from the front and back of the cone

Red = sound spreading mostly straight away from the center of the cone. This would be like the laser pointer you mentioned as a tool for aiming A-pillar speaker pods.

Putting it another way

Green = if you were holding the 6.5″ woofer in your hand, while it was playing bandwidth limited pink noise centered at 500 Hz, it should sound very similar or the same whether it is aimed directly at your face or if it’s aimed off to one side of your head.

With 3-way components the ideal approach with our crossover filters is to focus on the left column of frequencies. Our crossover type to begin the DSP setup is Linkwitz-Riley, 4th order(LR4). There is no overlap or underlap. More on that later.

  • 6.5″ woofer Low Pass Filter frequency ~ 500 Hz.
  • 3″ mid-range speaker Low Pass Filter frequency = 1,130 Hz.

How does this look in the DSP?

  • 6.5″ LPF 500 Hz
  • 3″ HPF 500 Hz
  • 3″ LPF 1,130 Hz
  • 1″ tweeter HPF 1,130 Hz

What’s a problem with this? This plan violates the rule of keeping the system reliable. The tweeters will likely sound distorted and soon they will break before you hit volume 42 of 50. A better starting point:

  • 6.5″ HPF 100 Hz
  • 6.5″ LPF 500 Hz
  • 3″ HPF 500 Hz
  • 3″ LPF 3,000 Hz
  • 1″ tweeter HPF 3,000 Hz

Why do we start with a Linkwitz-Riley 4th order crossover, and the mating speakers have the same crossing frequency? Electrically this results in a flat transition between woofer and mid-range, and flat between mid-range and tweeter. Predictability is what we’re after.

Simulation of the electrical response of the LR4 crossover with a 3 kHz LPF and a 3 kHZ HPF

Does this look like a difficult approach to planning your component speaker installation? Aiming component speakers doesn’t need to be a mystery. Leave your questions in the comments below.

Barry Schanz
Barry Schanz Enterprises, LLC
dba Rubyserv

Mastering Mobile Audio Systems Begins With a Plan

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