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Simple Acoustics,
Complicated Spouses

Issue 31

When I was a teenager, I told a girl that I loved her so much that I would die for her. She replied that if I died, she’d no longer find life worth living. So if I lost my life pushing her out of the way of a moving trolley, my sacrifice would be meaningless! What was I supposed to do, jump out of the way and let her take the hit? That would kill my sense of integrity and then I’d find life meaningless. What a dilemma!

My uncle warned me that women would complicate my life. Can’t live with them, can’t die without them.

That’s how I feel when I’m asked to assess someone’s audio system. If I’m honest and say that I don’t like the sound, the audiophile may feel that my life is no longer worth living. If on the other hand, I tell him it’s great when it’s not, it would be a meaningless statement which would kill my sense of integrity! It’s a no-win situation!

I’m often asked to provide audio assessments for members of our audio club. Perhaps it’s because some big players in the industry have lauded my home-made speakers. Maybe it’s because I’ve been President of our local audio club for 15 years and have experienced most every member’s system. Or maybe it’s because they know I’m not good at obfuscation.

Politely, I try to compliment only their system’s positive characteristics. Once done, it’s best to shut up, ask for a beer, and steer the discussion towards hops and barley. Invariably however, after a few glasses, the audiophile will ask what I really think. I always end up betraying my feelings. Maybe I should stop drinking.

My frequency-spectrum analyzer is my savior. If I don’t like the sound, I take a reading and point to the graph indicating the in-room frequency response. It’s not unusual to find bass peaks as high as 20 db, or giant black holes in the midbass. Then the readings can take the rap and I’m off the hook. That’s often followed by a discussion of how measurements are meaningless.  (Try explaining that to a speed cop.)

In one grand home, I was pleased to discover some accurate floorstanding speakers in a large audio room. That’s where my pleasure ended. The amps were some exotic design with a giant single output tube per channel. (My tube is bigger than yours!) The SETs were connected to cables which resembled a Boa Constrictor swallowing a sea turtle. Those lumps choked the sound as surely as the turtle choked the snake. Or was it the other way around?

I knew the speakers were a demanding load and that the amp couldn’t control them properly.  Jerry bought his system entirely on the basis of the “Recommended Components” list. He’s not a big reader. He’s the type who measures once, cuts twice, then buys more material—but he really should have read the full equipment reviews. Audio writers are usually pretty good about addressing compatibility issues.

I didn’t engage my spectrum analyzer. Didn’t need to.  The high frequencies were as compromised as Jerry’s hearing. He loved the sound and that’s all that mattered.

But many of the guys that call me don’t love their sound. Most of the time, it’s not due to the equipment. With the exception of some exotic designs, which seem to focus on maximizing one characteristic at the cost of all others, most equipment these days is soundly (!) designed and executed. If doesn’t sound good, it’s more often a result of poor room acoustics than equipment. Many of their listening rooms are as reflective as the Hall of Mirrors in Versailles.  Your canary can’t fly in a hall of mirrors and your system can’t sing there, I tell them. The reflections will totally confuse your cerebral processing center and cause it to crash.

However, like everything else, there are exceptions. One member’s listening room had plaster walls, a ceiling-to-floor window, oak door, tile floor, and a large marble coffee table right in front of the listening position. He claimed he loved the sound, so I deduced that this guy couldn’t hear either. I was wrong.

When it was time to audition, he moved his listening chair in front of the coffee table and close to the speakers for nearfield listening. He played small jazz groups and female vocals at low volumes. Big orchestral works at the volumes I prefer would have been a disaster in that room, but his material sounded wonderful. The hard surfaces added ambiance. Note to self: Check context before making assessments.

My house has a large garage, but a small living room unsuitable for audio. My wife fell in love with the kitchen and the bathrooms, so she decided we were moving in. My uncle warned me that women would complicate my life. I love my wife, so I made what I considered to be a huge sacrifice. In return, the garage was dedicated to motorcycles.

But how do I get big sound from a small listening room? That’s like asking how to get expensive speakers for cheap. It can be done but it’s not easy. My solution was to do the homework and build the speakers myself (but that’s a story for another time). As it’s always necessary to do the homework, I read everything I could on acoustics, and attended as many lectures as possible — both in person and on-line.

I discovered that bass problems can be solved electronically. Find the peak and reduce its amplitude by means of a parametric equalizer. I do it in the digital domain to keep artifacts at a minimum.  It’s not a perfect solution, but it beats 20 db peaks.

Nulls (black holes or dips) in the bass response are sometimes curable through relocation of the speakers, but not without compromising other factors of the sound. Subwoofers are best when using that method. Fortunately, our ears are much less sensitive to nulls than peaks, so I ignore them like the “news”.

Some audiophiles have baulked at introducing EQ into their systems believing it will somehow mess up the purity of the sound.  Most don’t realize that their phono pre-amp applies a more radical EQ curve than that needed for most bass correction.

I also learned that midrange and high frequencies cannot be successfully equalized by electronic means. It must be done with room treatment. But how?

One year, I heard a lecture by Anthony Grimani at The Home Entertainment Show in Irvine.  I was so impressed, I asked him to address our local audio club. Anthony has a great curriculum vitae  and constantly travels around the world, so it took a year before he could find some time, but he provided the solution to my big sound/small room conundrum.

His lecture lasted for almost 3 hours with lots of graphs, equations, and photos of concert halls, studios and home theaters. He explained how all his measurements were made, how the solutions were computed and implemented, and how they were tweaked to taste afterwards.  My head was spinning. I have neither the equipment, inclination, nor patience to engage in such a time consuming and painful process. I’m no rocket surgeon. When I looked around, it appeared that the rest of the audience weren’t rocket surgeons either.

Anthony must have sensed our qualms. Just before he closed, he added that after analyzing and treating many spaces for several decades, his company had discovered five consistencies in their results:
1.  About 20% of their clients’ walls usually needed absorptive panels.
2.  About 25% had to be covered with diffractive panels.
3.  Reflective points always needed to be covered.
4.  The front wall between stereo speakers responded best to diffraction.
5.  The area behind the listening position always needed absorption, especially if it was close to the back wall.

That formula was simple enough for me to understand, and I trust you’ll understand it as well.  The only question remaining is:  how much will the woman in your life complicate it?

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