Hear music the way it was intended to be reproduced - part 1
by, 10-13-2011 at 08:18 PM (4719 Views)
I love music, any kind of music really. As a former recording/mixing engineer/producer for 8 years, and lifetime audio freak, I had the privilege to record, mix, and master a wide variety of music. In this introductory post, we will look at the most important quality of reproducing music called, "timbre". Over a series of posts, the goal is to calibrate your sound system to be the most accurate reproducer of music for your ultimate listening pleasure :-)
In Wikipedia’s definition of timbre, you will see, aside from the technical definition, “In psychoacoustics, timbre is also called tone quality and tone color.” Tone quality is critically important in the reproduction of recorded music.
If you have ever heard live music, (e.g. piano, acoustic guitar, horns, strings, drums, etc.) then you may remember how it sounded. You may also remember when you went home and listened to something similar on your stereo that it did not have the same “tone quality”. Why?
Well, it so happens that another group of folks were also wondering this and produced this outstanding short article on, “Relevant loudspeaker tests in studios in Hi-Fi dealers' demo rooms in the home etc.” Of very particular importance is the frequency response curve in Figure 5. We will come back to that a bit later.
From the article abstract, “The "sound" of a Hi-Fi set is to a great extent room dependent. Very often, the final result is determined by the room rather than by the actual equipment. Fortunately, these influences may readily be measured.”
What the article is describing is musical timbre or tone quality. Unfortunately, the reality is that the tone quality reproduced by your sound system is highly dependent on your listening room. Before becoming a recording engineer, I was in electronics engineering world and as a hobby, built a great deal of speakers, amplifiers and preamps (still do). I also got into room acoustics and managed to get my hands on this wonderful device that revolutionized audio measurement techniques.
The TEF stands for time, energy and frequency. Very quickly you could analyze a room in 3D and determine the rooms “tonal quality” for sound reproduction. Based on that, you could treat the room with “Tube Traps” for bass frequency tuning, absorption materials for dampening overly live rooms, and “diffuser panels” to prevent slap echoes, but not overly dampen the room. I bought every possible book on recording and control room design and room tuning. I will provide a resource list later for those interested.
I had the privilege to observe Chips Davis design and build two multi-million dollar recording studios and control rooms from scratch using his infamous Live End Dead End (LEDE) room design. I then went on to “treat” several recording studios, controls rooms, critical listening rooms at audio dealers, and several private critical listening rooms using the TEF computer and lessons I learned from Chips plus the reference books.
My point in saying all of this is to pass on to you my learning’s to benefit you in your quest for the most tonally accurate sound reproduction system you can achieve with your existing equipment. No, I am not going to suggest you rip up your room or spend thousands or tens of thousands of dollars on acoustical measurement equipment and room treatments. What I am suggesting is that with a few key considerations, and a few bucks, you can make dramatic improvements to the tonal quality of your existing sound system.
Let’s get back to timbre and that B&K article, specifically Figure 5, “Optimum curve for hi fi equipment measured in the actual listening room.” Figure 5 is the key to tonal quality. That curve is the frequency response measured at the listening position. If your sound system measures close to this curve, especially the roll-off, then congratulations, you have achieved tonal perfection! Once you have heard a sound system that is calibrated to this curve, then you will understand exactly what I mean. Everything sounds “right” and all of a sudden the depth soundstage magically appears.
There is good reason for this curve, affectionately called the B&K house curve. In the recording studio world, in the control room, there will most always be a set of speakers that are tuned or calibrated to the B&K house curve. Why? Because it most accurately reproduces instruments that sound tonally correct. I.e. it has the best timbre. Additionally, when mixing engineers move from one studio to the next and listen to their mix downs, with this curve, it will have the same tone quality it had in the previous studio. Consistency is the key.
My wife, who is not an audiophile and puts ups with my tape measures and swept sine waves once commented, “I was in the garage and even there it sounded like someone is playing the piano in our living room.” That is near perfect timbre.
So the first step in understanding whether your sound system is tonally correct or at least as best as it can be, is to measure the frequency response at the listening position in your listening room and compare it to the B&K house curve. In my next post, I will show you how to do that without breaking the bank.