ahrensjt said:
I am in the "research" phase of upgrading my home audio. I am extensively auditioning speakers, particularly omni-directional designs.
Along the way I noticed a funny thing:
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- Some mfgrs (Gallo Reference/Due, Elac 608/609) propagate ONLY HIGH FREQUENCIES omni-directionally... mid/woofers are direct
I am not familiar with the Elac, but the Gallo speakers are basicly omni at all frequencies, even if not perfectly so. The midranges may be direct radiators, but the baffle width is narrow relative the radiated frequencies from the midrange, therefor most of the bandwidth of the 4" midranges is going to radiate in an omnipolar pattern.
(I think Mirage is in the middle with Mid / Tweeter as Omni, and Woofer as direct)
The bass frequencies are huge in wavelength relative to the cabinet dimensions, therefor bass will always radiate in an omnipolar pattern unless a dipolar bass radiator is used.
But I would be curious to hear from others' perspectives:
- are there technical/scientific grounds as to the "correct" omni design (high freq, low freq, or both)?
- what design is your personal preference and why (assuming an omni speaker)?
Omnipolar[or speakers approaching this behaviour] pattern speakers can sound the most realistic in my experience, but they do this by way of additional coloration of the original recording [as compared to a linear response direct radiator with a well treated room ] and they require a symmetrical room placement and sufficient distances from the walls in order to achieve this effect. This type of speaker requires you to arrange the environment around them if you want the specific advantages that they can produce. If you get a very hiqh quality omni-polar speaker, you can have the best of both worlds: hang diffusors and/or acoustic absorbers at the side and rear points of 1st reflection and it will not longer exhibit the omni-polar sound qualities, but instead sound like a direct raditor system. Remove the panels at will when you want to use the immersive spatial effects. The best of both worlds is possible with this option.
As an additional note of relevance, a speaker with wider and smoother off axis radiation pattern will sound better as compared to one with a non-smooth off axis response if both are used in average untreated rooms. All speakers have considerable off axis response, and if the off axis response that is reflected around the room is not similar to the on axis response, the human auditory perception system detects this difference as a sound quality decrease according to credible perceptual research.
-Chris
