|Bob Hodas on Proper Speaker Placement|
|Home Theater Feature Articles Audio Related Articles|
|Written by Bob Hodas|
|Thursday, 01 May 2003|
AV Education on RHT:
Bob Hodas on Proper Speaker Placement
When the esteemed editor of AudioRevolution.com, Bryan Southard, contacted me to write an ongoing column on acoustic advice for home audio systems for RevolutionHomeTheater.com, I replied, "No problem, I've analyzed more consumer level systems than I can remember." Southard then added in the challenge of writing my column from the perspective of a “do-it-yourselfer” who has made some significant investments in his gear but is tired of hearing that he needs to constantly invest more in gear to get better sound. We all know your room and your system setup is essential to the overall success of your sonics. In many cases, it is more than the gear you have purchased.
In a world where there are very few rules of thumb, in my upcoming features, I'm going to give you my professional guidance in solving some of your system problems on your own. This is going to require some intensive listening and a little legwork at times, but isn’t finding that last percentage of performance in your system part of the fun?
Ultimately, you are going to use your ears as your analyzer, as opposed to using a tool like I use in the Meyer Sound SIM System II. This article is aimed primarily at the "do-it-yourselfer," so the acoustic solutions are the least expensive options that I could think of and "some assembly is often required." I will also advise you on effective products that you can purchase from dealers.
Professionally, I am what the pro audio guys call a “room tuner.” I travel around the world, from Sony Studios in Tokyo to Abbey Road in London, helping audio professionals tune their sound systems in their rooms, using acoustic and electro-acoustic solutions. I also tune high-performance home theaters and audiophile listening rooms. Some of the more notable home clients include George Lucas, Shaq and Intel Chairman Andy Grove, as well as much smaller projects for both the editor and publisher of AudioRevolution.com. I do both a system consultation via remote, which starts at $900 per room, and on-site tuning and EQ, which ranges from $1,500 to $3,500 per session. For readers of RevolutionHomeTheater.com and AudioRevolution.com, my advice is, of course, free.
Setting Up Your Speakers
Before we can think about acoustic treatments, we need to optimize the speaker positions in your room. This is the single most important task you can accomplish to improve your system’s performance. It is very important that you become extremely familiar with the speakers you are going to use. You will also want to take a good look at the manufacturer's frequency response charts. Remember that these are anechoic measurements. As soon as you put your speaker in a room with boundaries (walls), the bass response will start to change significantly. Bass response will build up even more when you place the speaker against the wall or in a corner. However, the response charts are useful for knowing what the speaker’s limitations are. For example, bookshelf speakers can roll off dramatically after 125Hz, so you don't have to be too concerned about deep bass problems when positioning them. Using a wall or corner may even be to your benefit. You’ll also want to pay close attention to the recommended position for proper phase alignment. For some speakers, it's directly aligned with the tweeter. For others, it's a point between the woofer and tweeter. It depends on the design, so check the manufacturer's literature. Hopefully they cared enough about this when building your speakers. You want to make sure, when you position your speakers and listening position, that this alignment point intersects at your ear level.
For this month’s model, I am assuming that your room has four walls with equal spacing, i.e., the common rectangle rather than an “L” shape.