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Archive for januari, 2011


Sing along

No, I am not going to talk about the usual response I get from wife, daughter and son when I can´t help myself and sing along to a catching piece. But there is a common denominator here with what this entry is about.

Been to a hifi shop lately? See any speakers there? Ok, lots, I thought so.

A fair share of all speakers on the market employ some form of reflex function to enhance the bottom end. This function is a so called Helmholtz resonator. A cavity, open in one or both ends will resonate at a fundamental frequency plus its harmonics , related to the volume of air in this cavity.

Air has mass, approximately 1,2kg´s per cubic meter. Not insignificant. After the onset of the first tone, transient etc. the resononant cavity will at first resist to change its state, then it will gradually follow. Once the tone disappears the air in the cavity is now mass in motion and will resist stopping, gradually decaying as acoustic energy (kinetic energy in air molecules)  is converted to heat.

Back to the hifi shop, in this environment you listen to a creation of your liking, but would you believe this is the worst possible place to do it in?  Why is this so?

As the target speakers play out the remaining sets of speakers will wake up and their reflex ports and speaker drivers will come alive. What happens is that you may get either an increase or decrease in the rooms acoustics that will color the listening experience severely.  It will also impair the rooms response to impulses.

One pair plays and all the others sing along.


Une affair de gout

”Une affair de gout” , this is what the French say about matters of taste

There is a bit of a buzz out there surrounding directional or omnidirectional loudspeakers. Which are best?

The reply is neither. But, why?

In Earo´s white paper “nearly a complete case for the horn”, it is explained why audio reproduction can never be more than an illusion of a reality. Even so, a very good and satisfying illusion at times.

So then, we could conclude that us audiophiles strive to maximize satisfaction. Just like watching a movie, eating a skillfully prepared meal, visiting a gallery or just watching a star speckled night sky. A sensory tickling.

Already as early as in mid 1970´s Earo worked on omni-directional designs and even sold a few of them.  Omni-directional horns are rare but not new, more than 60 years ago Michelson designed a backloaded, single driver horn employing a diffuser for omni-directionality. Earo ´s work on speakers began with omni-directional single driver horns more than two years ago and a release is planned for later part of 2011.

But let me just establish where we stand here. Omni-directional speakers, regardless of type of design can not be more accurate than a directional loudspeaker. Omni-directionality implies that energy is projected in all spatial directions in the room. This will excite nodes more than a directional speaker would (with exception of dipoles) and increase the influence of room reflections that add and contribute to the perception. This will happen in a relatively larger extent than when using directional speakers. Since it is all an illusion, it is neither good nor bad. Omni-directionality will make use of the listening rooms acoustic properties to a significantly larger degree than a directional one will. This puts a lot of the success in the hands of the owner of the room in question. This does not make matters easier, instead it complicates them.

As for our hearing mechanism, the absolutely most significant part is the arrival of the auditory clues in the first and direct sound. Both types of speakers can fulfill this criteria if designed and set up properly. What happens next is more a matter of taste, does the coloring of the room acoustics please you or is the opportunity to enjoy reproduction in more places in the room important?

In physics, it is commonplace to accept a fact (based on Heisenbergs uncertainty principle) you measure with increased resolution in one domain you lose the ability to do so in another. Similar things go on here, the tradeoff is for increased spatial distribution, accuracy becomes less. The point is, there is no free lunch. You want a broad image in the room? Ok, but you lose the accuracy of the sweet spot.

I have seen marketing material that go at length to argue the superior musicality of omni-directional loudspeakers. How can one argue taste I wonder? Some even claim this principle to be the only correct one for reproduction. No one at Earo would ever make such claims as we don’t believe this can be true. We do believe that an omni-directional speaker system, designed under the same principles as we base all our products on, can give an outstanding musical experience. That´s it, an experience.

Never will we claim that omni-directional speakers more accurately reproduce what the recording and mastering engineers heard as long as they use directional speakers for mastering.

In principle all recorded material is mastered using both near and farfield directional loudspeakers. A recording engineer, with some level of sanity, would not let the room influence this process.




today the website was finally cleaned up after a bit premature publishing before T.H.E Las Vegas Show

New version white paper is soon available