Reflected Sound as the Cause of All Car-Audio Evil

Is Reflected Sound Evil?

Ridiculous! 
Some argue that reflected sound is utterly undesirable within the car. They use this to support their thesis that speakers on "A" pillars are the only way to reproduce good sound. 
In my Low Stage Part 01 - Two Speakers post I addressed the issue of perceived height. I directly targeted the argument often made that real acoustic performance is only possible by using speakers mounted on the "A" pillars. Well, recently, it seems that the autosound competition circuit has been getting further addicted to the same Kool-Aid. This time, though, I would like to address the argument that speakers on the "A" pillars are superior because of their ability to deliver direct sound and that all other installation methods will fail due to their reflected sound character.
Unfortunately, the optimistic souls that make such argument miss centuries of empirical historic evidence and thousands of modern sound reproduction methods that would negate their argument.
To start, a vehicle is such a small enclosure that it would be a stretch to think that the reflected sound of even those speakers mounted on "A" pillars lack a substantial amount of reflected sound. Whether from the immediate surrounding boundaries like the windshield or windows, the signature sound of any car is very different from that of even small home rooms because of the large amplitude of the reflected energy present within vehicles. I remember auditioning a vehicle with pods for a set of Dynaudio tweeter and mid built onto the "A" pillars. The amount of energy that coupled to the surface of the near-side window was so large that getting anything to image was everything but impossible. And that says nothing about the poor tonal color created by the coupling. Perfectly great drivers were made mediocre. I happen to know Dynaudios very well and immediately sensed something was very wrong. In essence, the windshield pods' response was heavily influenced by their reflected energy, which is what creates the coupling I mentioned.

French Horns mostly do reflected sound

Then there is the issue that reflected sound is much more common that it gets credit for by detractors. For example, next time you go to listen to your local symphonic orchestra, pay attention to French Horns. French Horns are routinely played towards the back of the stage. Therefore, it is their reflected sound that we listen to when we audition any of the great orchestral works that we love so much.
It should therefore be noted that I have yet to hear complains from any professional musician about the quality of the sound of rear firing French Horns. Besides, I doubt anyone in car audio would claim to have better hearing than those who receive great incomes as compensation for their more than ten thousand hours of commitment to playing music. In fact, if such was the case and reflected sound was clearly objectionable, more than one of the many liberal orchestra conductors out there would have made immediate changes. But as it turns out, French Horns have a nice and pleasant characteristic sound. Could it be that their reflected energy is pleasing rather than objectionable?
Don't take me wrong, I have nothing against direct sound. My home speakers, which I designed presumably in a way I endorse, use direct sound as the core of their design. It is just that I also don't have anything against reflected sound either. In fact, I am comfortable with both. No threats to my self confidence here. Whether the direct sound is dominant or not, I am happy with whatever it is, so long as it sounds great.
Yes, I know that someone could argue that they can easily tell that French Horns are reflecting their acoustic energy. After all, they sound larger than they should, based strictly on their physical size. When reflected, sound waves seem to emanate from an array rather than a single point. In other words, their wave front is more parallel than concentric. But the same thing happens when waves originate from sources located afar. If it were not for the loss of energy as the wave travels, these long distance sources would present a parallel wave front. Moreover, aren't arrays used in plenty of direct sound applications? So what would the difference be between a reflected wave that now looks like that from an array and an actual wave resulting from an array?
In any case, outside of describing sound as seeming larger, it would be very difficult for someone to argue that their physiology has made them capable of differentiating between a concentric wave front and a parallel one. Let's remember that all circles are made up from tangential lines. If in doubt, check your Calculus books for a refresher.
Now let's go back in time to Dallas, Texas. Some time ago, James Feltenberger, the fabulous Dallas Symphony trumpeter, gave me the honor of listening to his fantastic trumpets played a few inches from my face. At the time, I anticipated getting my ears ripped off. After all James has quite the lungs and trumpets are often regarded as bright instruments. But to my surprise, I never reached anywhere near the threshold of pain. On the contrary, the sound was sweet and full-bodied.
What? Am I implying that trumpets are not bright? And what body am I talking about? Don't trumpets just have a thin metal pipe bent a few times? Well, yes and yes. Trumpets, at least when played by real musicians like James, are warm despite lacking a large wooden resonator like those from Violins or Cellos. It was clear that the direct energy coming from the front of the trumpet was far from being the only defining factor of the resulting sound. The rest of the metallic pipeline energized the room just as much, but in an omni-directional fashion.

MBL 101 Omnidirectional Speaker

So how is it that most sound systems don't reproduce trumpets as I am describing? Well, the answer may be that those systems are simply not transparent enough. But if in doubt, I can undeniably certify that James was not hiding any cheese-ball Bose speakers anywhere in the room as he played music for me. Sorry for offending cheese-balls. I digressed.
So, we have looked at the fact that professional musicians use reflected sound without much fuzz. We also explored how even small-body instruments like trumpets strongly energize space in an omni-directional fashion rather than a just a direct one. This explains why there is a large number of uber expensive home speakers that sport omni-directionality as their main feature. Enter the German made MBL 101. I am sure that more than one car guy missed this engineering beauty. And then there are plasma speakers which, besides being omni-directional, are also quite rare.
It is now time to look at the venue. There are generally two types of orchestral theaters: large and small. Their size generally depends on the era when they were built. Most small theaters were built after the middle ages. Since Baroque groups were made up from a few players and lacked percussion or grand pianos, there was a need for theaters that would amplify their music. So, the horse-shoe shaped theater was born.
Later as more and more Opera was enjoyed through out the old continent, these small horse shoe theaters served well to those attempting to transfer a broad range of the musical notes emanating from their mouth. It is generally accepted that these theaters project a beautiful sound. Whether talking about the European originals or their more modern copies built in say, Guanajuato, Mexico, I can attest to their great warm sound.

Mies Van Der Rohe's Barcelona Pavilion

Then orchestras begun to get massive. 19th century composers started to pump up the dynamic range while blasting the sound to 10. To accomplish this, they needed lots of violins and flutes. They also added quite a bit of percussion and big Pianos. So, theaters had to get bigger. And since architecture had also changed, theaters where no longer built as horse-shoes with balconies heavily decorated in golden stuff; a la Donald Trump.
Instead, do you remember Mies Van Der Rohe's Barcelona pavilion and the whole Bauhaus architectural style? Big open spaces, large concrete surfaces and lots of metal created the look that has influenced most modern music halls since.

Royal Festival Hall, London, UK

While in England, I spent quite a bit of time doing critical listening as a wondering member of the audience at the Royal Festival Hall in London. Let me tell you, the warmth of the old theaters disappears as soon as yo step into one of these newer beasts. But by no means does it mean that the new sound houses are bad; many are fantastic. The good ones sound very open and fast. They are simply not as warm as Baroque venues.
The main difference comes from the fact that in post medieval theaters direct sound takes a second seat to reflected sound (pun intended).
While warmth happens within modern theaters for listeners located at the very back of the balcony section, old theater magic happens for all listeners. Baroque theaters seem to use the whole theater in a similar fashion to how a guitar uses its resonant box. The sound is amplified and its color changes. I think that it is almost impossible, without any comparative reference, to judge exactly how much of the resulting sound comes from reflected energy and how much from direct sound.

Sample 1:

Sample 2:

Listen to these two sound samples here. They were captured by recording a gunshot inside the San Carlo Opera House in Naples, Italy, at two different seats. For sample one, the microphone was positioned a few feet from the stage. For the second sample, the microphone was positioned inside the most prestigious of locations within this very well loved Opera hall: the royal box. The theater is known for its incredibly sweet acoustics. Plenty of Operas have been enjoyed by audiences for centuries.
Without listening to sample one, would you be able to certify whether the dominant energy is direct or reflected? Look at the charts. Reflected energy is, as a matter of fact, what dominates the impulse graph.
Only after directly comparing both samples would most audiences note the difference in decay and distribution in energy. This means that without any preconceptions or the ability to change seats, royal guests would have experienced a much richer and musically engaging acoustic presentation that left nothing to complain about.
Evidence corroborates this statement. For centuries, no one has complained about the lack of direct sound present in these acoustic venues. Which means that either direct sound is not all that it is claimed to be or that millions of people who listened to real music, in ways we only read about today, were wrong. After all, what would they know, right? Without modern MP3 players they surely missed the best sound possible, right? ... Not.

Veritas Waveguide

To finalize, I will call on the obvious. For those in the car audio industry, do any of you remember Waveguides? Well, with the exception of the Illusion ones, all other were purveyors of more than 99% reflected sound at the very least. From the moment that the dome energizes the compression slits within the motor, to the time when sound waves crash onto the elbow walls inside the throat area, there is just nothing direct about their sound. Yet, tens of thousands of waveguides were sold without resulting on any reflected sound complains. As for the performance outcomes, there were at least hundreds if not thousands of installations achieving great sound.
Again, I have nothing against direct sound. It is just that within the car environment, where reflected sound is so dominant, I argue that great results could be achieved by dampening direct sound and letting reflected sound do its magic unobstructed. In a way, that is exactly what the designers of compression drivers attempted to do. It is also a technique I have used in enough circumstances as to trust it to be a viable alternative in the quest for best sound. Moreover, I am not the only one. Chris Owen was in fact the person who introduced me to this technique. Then there was Dick Olsher from Stereophile Magazine who at a Consumer Electronics Show demonstrated speakers that fired backwards rather than directly at the audience.
Here, I would like to remind all experts of what the later Richard Feynman would say "Science is the belief in the ignorance of experts". In other words, to be real scientists, let's not fear changing our minds just because of preconceptions. If a new scientific test results in a new theory you happen to disagree with, just as Einstein distrusted Quantum mechanics, the problem may be within you and not withing the test; again just as history placed Einstein on the wrong side of the particle theory debate.

Double Slit Electron Experiment

Talking about Quantum theory, let's wrap this up. It all comes down to the fact that we are listening to waves and not particles. To see what this means, read about the Thomas Young's Double Slit Electron Experiment that so baffled physicists about a century ago. When electrons (particles) pass through double slot openings, the expected particle behavior fails. Instead, they behave as waves; perhaps because they are energy fields, if you take the position of string theorists. In any case, this Quantum Physics experiment shows the difference between particles and waves; a difference that many audio experts seem to completely miss. In their minds, sound wave behave as particles. Yes, it's crazy...