When I was a teenager, I told my girlfriend that I loved her so much that I would die for her. She replied that if I died, her life would no longer be worth living. So if I lost my life pushing her out of the way of a moving trolley, my sacrifice would be meaningless!
What would she have me 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 Catch-22!
My uncle warned me that women would complicate my life.
I’m often asked to make audio assessments for members of The San Diego Music and Audio Guild. Maybe it’s because some big players in the industry have lauded my homemade speakers. Perhaps it’s because I’ve been president of the club for over 20 years and have experienced most every member’s system – and many at CES and other shows over the years.
Making audio assessments is another Catch-22 situation. 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 them it’s great when it’s not, I’d be compromising my sense of integrity!
So, I compliment only their system’s positive characteristics. Once done, it’s best to shut up, politely 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. This is tricky because he may have an emotional fortune invested in his equipment. But beer breaks down my defenses. In the end, I always end up revealing my true impressions. Maybe I should quit beer.
What eventually saved me from this dilemma was a frequency-spectrum analyzer. Now, rather than offer a poor appraisal, I’ll say, “Well, let’s take a look at the in-room frequency response.” Then I’ll take a reading on a pink noise source and share my results. Sometimes it reveals peak to null variations of over 18 dB.
"See Larry, that’s why your system sounds the way it does.”
By using this method, the device takes the rap and I’m off the hook (well worth the $1,500). That’s sometimes followed by a discussion of how measurements are meaningless (don’t try that with a cop who busted you for speeding).
For some members, accuracy is not an issue. On a first-time visit to one member’s home, I was impressed with the $250,000 floorstanding speakers in his large acoustic space. My heart sank, however, when I saw that he was feeding them with a pair of tube monoblocks. I knew the speakers were power hogs needing at least 500 watts per side, but the tube amps produced only 10 percent of that. They were connected via fat speaker cables each housing a big lump – like a python swallowing a sea turtle. That lump most likely held an inductor to roll off the high frequencies, which would tax the amps even more.
Predictably, the amps just couldn’t control the speakers properly, so the system sounded as though we were listening to the symphony in the foyer. Paco proudly told me he bought his system based entirely on one magazine’s “Recommended Components” list.
But he’s not detail-oriented. Paco's the type to measure once, cut twice, then buy more material. If he’d read the full equipment reviews, he’d have learned that audio writers are pretty good about addressing compatibility issues.
I didn’t engage my spectrum analyzer. Didn’t need to. The system had no deep bass, the mid-bass was as flabby as Paco’s waist, and the highs were as compromised as his hearing. But he loved the sound, and in the final analysis, that’s all that matters.
But some of the guys who 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 the others, most equipment these days is quite accurate.
If the system doesn’t sound good, it’s more often due to poor room acoustics than equipment. Many listening rooms are as reflective as the Hall of Mirrors in Versailles. "A 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."
The Hall of Mirrors at the Palace of Versailles near Paris, France. Courtesy of Wikimedia Commons/Myrabella.
There are exceptions. One member’s listening room had plaster walls, floor-to-ceiling windows, oak doors, a 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. When I sat down, he played a few small jazz groups and female vocals at low volumes. The soundtracks I enjoy at concert-hall volumes would have sounded terrible in that space, but his material sounded wonderful. The hard surfaces barely came into play. Note to self: check context before making judgements.
My house has a small living room quite unsuitable for audio. It’s actually more of a hallway to the bedrooms. My wife fell in love with the kitchen and the bathrooms, so she decided this was the house where my system should go. My uncle warned me that women would complicate my life.
I love my wife, so I made what I considered to be a huge compromise. She got control of the kitchen and bathrooms, and I got control of the garage and the living room. So the garage was converted to a motorcycle shop and the living room to an audio salon.
The next problem was, how to get big sound from my small listening room? That’s like trying to get expensive speakers for cheap. It can be done with resourcefulness, but it’s not easy.
My solution was to build the speakers myself (that story will follow this one in the next issue).
Once built, it was necessary for me to understand acoustics. I read everything I could find, and attended as many lectures as possible – both in person and online. I discovered that bass problems below 250 Hz can be solved electronically. Just find the peaks and reduce their amplitude by means of an equalizer. That usually reduces the nulls which typically appear on either side of the peaks as well. I do it in the digital domain as that offers much more control than passive EQ. It’s not a perfect solution, but it certainly beats 18 dB frequency response variations.
Some folks prefer passive bass EQ by means of using bass traps, or relocating the position of the speakers. But bass traps would need to be about eight feet thick to trap the lowest frequencies – which would extend halfway into my listening room. Furthermore, the best location for woofers is usually the worst location for mids and tweets, a Catch-22 for owners of tower speakers.
The solution is a system featuring separate subs and stand-mount monitors. That allows the owner to place the subs at the ideal location for bass, and the monitors at the best location for mids and highs. When implemented properly, this application is very effective.
As for those who insist that all drivers must be aligned, since when are the tympani aligned with the violins?
Analog audiophiles have balked at introducing electronic EQ into their systems believing it will somehow mess up the purity of their sound. What they don’t realize is that RIAA equalization is often far more radical than that required for room correction. Some of the best phono preamps actually use digital EQ, just like my equalizer.
Equalizers correct bass frequencies very effectively, but in my experience, in-room frequency anomalies above 250 Hz cannot be successfully equalized by electronic means. The phasing problems which result are too disturbing. They must be handled by means of acoustic room treatment. But how?
In June of 2013, The Home Entertainment Show in Irvine featured a lecture by acoustician Anthony Grimani from MSR Acoustics. I will forever be grateful to Mr. Grimani and T.H.E. Show for this opportunity. It opened my eyes. I was so impressed, I asked him to address our local audio club. He has a great curriculum vitae and travels around the world constantly, so it took several months before he could find some time to address the San Diego Music and Audio Guild (see header image).
His academic-quality lecture lasted for almost three 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.
Anthony Grimani gives a presentation at The Home Entertainment Show 2013.
My head was spinning. I’m no rocket surgeon and have neither the equipment, inclination, nor patience to engage in such a time-consuming and painful process. 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 his presentation, he added that after analyzing and treating many acoustic spaces for several decades, his company had discovered five consistencies in their results:
1. About 20 percent of typical clients’ walls need absorptive panels.
2. About 25 percent should be covered with diffractive panels.
3. The front wall between the stereo speakers responds best to diffraction.
4. Reflection points between the ears and the speakers must always be treated.
5. The closer the back wall is to the listener, the more it needs absorption.
Anthony works mostly with large spaces. In my experience with smaller ones, I would add these three rules:
6. Nearby corners (at the floor or ceiling) reflect sound like megaphones and should always be treated.
7. Flat surfaces like coffee tables add glare to the mid/high frequencies due to reflection and those surfaces should be damped or eliminated.
8. If the front wall is less than four feet behind the speakers, the soundstage can be made to sound deeper by damping the area behind (not between) the speakers.
As for damping materials, that’s a whole other subject which, in my opinion, even some acoustic product manufacturers don’t properly understand. It takes different materials to best absorb different frequencies.
Once the audiophile understands and acts on all this information, the only question remaining will be: how much will the spouse in your life require you to compromise your acoustics for the sake of aesthetics?
My uncle warned me that women would complicate my life.
This article was first published in Copper Issue 31, and is revised here.
0 comments