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The Crux of “Audiophile” Sound Quality

I’ve spent a bit of time in the DIY audio world; designing and building home theater speakers, and designing and installing car audio systems that strive for high levels of sound quality. I’ve designed and built countless sound quality-oriented subwoofer enclosures, tuned active and passive crossovers, and worked with some fantastic equipment. While not proclaiming that I’m an expert in all fiends – I’m still always learning from those who have far more experience than I – I’ve come to the realization that there’s a crux when designing an audio system. That is, a decisive point of difficulty. It’s probably not what you think though…

The Crux of “Audiophile” Sound Quality

 

Some people start working in mobile audio and give up after a few years of discovering just how much work it takes to make a car sound truly good. I’m not talking about Best Buy installed Kickers kind of good, but 3-way front active systems with a perfectly tuned sound stage and extensive ceiling, door, floor, and trunk sound treatment, and that’s just a start. Some people simply don’t want to go through that expense only to discover that the noise floor is still too low once you start driving. Still, that’s not the crux this article will focus on, as you can put together some incredible sounding systems on a modest budget, or you might have the budget to get the best parts money can buy. The thing that put this all together recently was my recent research and discussions with other experts on the topic of music and recordings.

One of the first things you’ll notice when upgrading your sound system is that everything sounds clearer. Highs sound crisper, bass sounds tighter and deeper, guitars sound more lifelike, and vocals sound clearer and more realistic. After that initial awe, a different reality sets in. The better you make your sound system, the worse some music sounds. Let me explain.

Compression

The first thing you’ll discover is compression. You may not have cared about this with your stock radio in your car or a cheap set of home speakers, but you’ll definitely start to care. You’ll find that some music simply sounds clearer than other music, and you’ll quickly learn that files such as MP3s are often compressed to the point of severe compromise. Compression is a method through which an audio file is reduced in size in order to make it more portable and less demanding on space, with a reduction in sound quality being the end result. MP3 and M4A files are one example of this. Unfortunately, they are by far the most common formats, and you are not very likely to buy a high bitrate in excess of 192KB/sec from the Amazon music store, to name one example. The lower the bitrate, the more of the sound quality is compromised. You won’t notice it with a cheap set of speakers as the quality won’t be high enough to reveal the detail you’ve lost during compression, but once you upgrade your sound system, you start to notice.

Mixing/Recording Quality

Another thing you’ll notice is that recording quality differs greatly between artists. Some recording studios simply can’t produce a good sound for whatever reason, be it equipment, lack of skill or talent, or what have you. There are some songs that you listen to and think “wow, this is just plain terrible,” while having the same instruments and same vocals sound vastly better in a different song. In fact, you can even find a big difference between albums from the same artists. There are some U2 songs that I simply can’t stand to listen to, while there are very few Matt Nathanson tracks that I don’t enjoy due to the quality of the recording. It’s something I hadn’t put much thought into when I was first starting out and learning about true sound quality, but something that became all too clear as I reached higher performance levels.

On a side note, trying to tune a crossover or equalizer around a poorly recorded or mixed track is a recipe for failure. You’ll spend an insurmountable amount of time, effort, and ultimately frustration trying to make a poorly recorded song sound good, and it will drive you crazy when every other song after that sounds “off.”

Mixing/Recording Styles – Bass & Dynamic Content

Dynamic Content

This is something that my friend Matt Borgardt brought to my attention more recently, and something that has explained why I’ve had such an annoying time trying to tune parts of my car’s system. To begin, there was a notable shift after about the year 1999, when recording artists began to record music…differently. One of those differences was related to dynamic content. To understand dynamic content, you have to understand crest factor. Before I go any further though, I do want to point out that this is not intended to be a blanket statement, but simply to point out a frequently occurring reality. A widely circulated article written by a JL Audio engineer with regard to amplifiers and clipping describes crest factor pretty well:

“Crest Factor” is the difference between the average level of the signal and its peak level. For example, a pure sine wave has a “crest factor” of 3dB, meaning that it’s peak level is 3dB higher than its average level. We all know that 3dB represents a power factor of 2, so another way to look at it is that the peak power of the signal is twice that of its average level. So, if we play a sine wave on our 100 watt amplifier, just below its clipping level, the average power (over time) the speaker is needing to dissipate is 50 watts…

Music has a significantly higher crest factor than sine waves or square waves. A highly dynamic recording (Sheffield Lab, Chesky, etc.) typically has a crest factor of 20dB or more, meaning that its average power is 100 times lower than its peak power. So, if we play our 100 watt amplifier just below clipping with the typical audiophile recording our speaker is only needing to dissipate 1 watt of average power over time.

Modern commercial recordings typically exhibit crest factors of around 10dB, meaning that the average power is 10 times lower than the peak power. So, our 100 watt amp just below clipping would deliver an average power over time of 10 watts that the speaker has to dissipate.

As the author of this quote pointed out, modern commercial recordings have crest factors of around 10db. However, highly dynamic recordings have a crest factor of 20db or more. I would argue that some modern recordings have crest factors of under 10db. If I had to paint a visual picture of this scenario, the less dynamic the content and lower the crest factor, the more blurry the picture looks, and the more dynamic the content and higher the crest factor, the sharper and more detailed the picture looks. This is not meant to be confused with clarity, however, but it is meant to point out a difference in music. When every component is played at the same amplitude, it starts to sound like one big blur of sounds. If our reference point was 86dB, then just about every bit of a non-dynamic track will be played at or very close to 86db.

A cheaper set of speakers would not have been capable of reproducing that dynamic content, so you would have simulated a lower dynamic content and lower crest factor simply as a function of the deficiencies in the speakers you were using. You wouldn’t have noticed the difference between music simply because your speakers weren’t capable of reproducing those differences.

Bass

Similar to the previous point, there was also a shift in bass notes in commercial recordings after the year 1999. Again, this is not intended to be taken as a blanket statement, but as a frequently occurring reality. The fact of the matter is that bass has changed over the years. What we may write off as mere differences in genres are actually differences in recording and mixing of tracks. Take classic rock for example, and you’ll find quick, tight, and accurate bass beats, with modest presentation of acoustic and electric bass. Fast forward to modern rock, and you’ll find an entirely different type of bass. Starting in around 1999, recording studios began altering bass notes, making them larger, longer, and deeper. In some instances, the actual tones have also been altered. I refer to this as synthetic bass, and the degree to which bass is synthesized varies greatly between artists and genres of modern music. Rap/hip-hop, dubstep, and other electronic music uses synthetic bass notes, but you’ll also find synthesized bass notes in genres such as rock, pop, country, and their varieties, just to  name a few. A personal note of mine is that it has become increasingly more difficult to separate the snappy kick of the bass drum from the thump of the synthesized bass note in some modern music.

The difference between synthesized and non-synthesized bass notes is nearly imperceptible with cheap speakers simply because, similar to the point regarding dynamic content, they are incapable of accurately reproducing the differences. With a cheap set of speakers, just about everything sounds like a thump or a boom. Furthermore, this plays heavily into the way a system is designed. One of the first things I have always asked a person before making a recommendation for a subwoofer and enclosure is what type of music they listen to. While I was not always aware of the differences between historical time periods, I was aware of the differences in bass styles and the genres in which they are found. A heavier coned subwoofer such as the Dayton HO 10 may be perfectly suitable for modern music in a sealed or vented alignment, but one could definitely tell an undeniable difference between a Dayton HO 10 and an Image Dynamics IDQ1- V.3 subwoofer in classic rock, classical, or any other music where a far larger frequency band is needed.

 

The crux, in conclusion

The challenge you have to consider is, how far do you want to take your quest for sound quality? The more detailed you make your speakers, the bigger the differences between highly compressed and minimally compressed music will be, the bigger the difference between excellent and poor recordings will be, the bigger the difference between dynamic and non-dynamic content will be, and the bigger the difference between natural and synthetic bass will be. Furthermore, once you’ve heard those differences and heard what music should sound like, you may not be able to go back. Many who have gone down this road will admit that they’ve simply stopped listening to certain artists or certain albums simply because of the way they are recorded. Some modern rock has such little dynamic content that it all sounds like one big blur; almost akin to white noise during some parts of the track. The exact opposite could be said of Billy Idol or Jethro Tull. There are songs I used to love, but avoid listening to simply because of details I never heard before and wish I hadn’t heard. With some effort, you can find a less heavily compressed version of a favorite MP3 file, but you can’t “un-synthesize” bass, and you can’t go back in time in the recording studio and smack the staff for doing such a terrible job of recording.

As you explore the area of true audiophile grade sound quality, be prepared to hate songs you currently love, and pick up some new tracks and artists you may have never heard of before, but be careful how far you go, because once you’ve heard what music is supposed to sound like, it’s almost impossible to go back.

– XTR

 

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