Guest post by author Robert Wayne. This is Part 2 of Audio, the Quest for Individual Nirvana.
Speakers are the hardest part of the puzzle to get right, there are thousands of options and, in my experience, are the single most important piece of the audio system. You must make a number of important decisions at this time or it will cost you a lot of money over time and even more aggravation. Now is the time you have to be honest with yourself about what you want, what you can afford and ultimately what will fit best into your life.
The first serious decision you have to make is multi-channel or stereo, there are many ways of configuring a multichannel system, 5.1, 7.1, phantom center channel or even 3.1. We won’t get into the break down of all the possible configurations of multichannel and how they can be implemented in this article, but will address the subject in much greater detail as this saga unfolds. If you decide to go multi-channel many stereo speakers are no longer options because there is no complimenting center or surrounds, of course you could run the same speakers in all 5(or 7) channels but that may get expensive and create other headaches. Typically, I’d recommend using center channel designed to work with the stereo speakers and a complimenting surround speaker from the same manufacturer and the same line of speakers. To pull of multichannel properly voice matched speakers are imperative, trying to combine mismatched brands of speakers in a multichannel system will never yield great results. Personally, I am a stereo guy, I don’t like noises coming from behind me, I’ve experienced excellent multichannel systems and can enjoy them, but at the end of the day I want to come home and enjoy a simple two channel system. One more quick note about this before we continue, there seems to be a stigma associated with stereo’s that you can’t have a home theater and that is not the case. You can very easily have a 2.1 system or even just a basic two channel system with display to view movies. Due to the simplicity of using fewer components, your budget will go much further and allow you to buy higher quality components. A Phantom setup, does not employ a center channel, just a front left and right speaker, by using higher quality speakers it allows better imaging and in many cases a very strong, pronounced center image, when done right it will leave you speechless.
Picking the right speaker for you also means picking the right speaker for your room. Room and speaker interaction can vary greatly, if you have a smaller room a large speaker typically won’t work well and vice versa. Even if a speaker auditions well in a fancy audio salon it may not perform to the same level in your home. There are tricks that audio shops use to make speakers perform better, room treatment that go in corners, side, front and back walls, there are simple tweaks that you can mimic at home for very little money, but again, this will be the subject of an article to come. A common thing they do is to have splayed walls, this technique, including the ceiling, does offer better sound, but in most homes simply is not an option. When auditioning, pay attention to the room your in, it may give you a false sense of what you’ll be capable of getting at home.
Let’s talk about specs for a while, of course there are the physical dimensions of the speaker, they should be available on the manufacturers website and you should be able to see just how big they are before you buy them. I would never recommend buying a speaker without listening to it first, not only do you get to hear its “voice” but you get to see the finish, the actual size, the quality of its fit and finish, etc. Next is the weight, while not the most important spec, it’s worth noting roughly what the speaker weighs, after all you will have to move it around from time to time, set it up and live with it. If your single and weigh 100 lbs., you probably shouldn’t buy a speaker that weighs 800 lbs. and plan on moving it much. Shipping and handling can become troublesome with large and heavy speakers, so think about that before purchasing. Weather it is resale or you moving, it is a problem you have to deal with eventually. Lets move on to more interesting specs and what they mean in your life.
Frequency response, it is important to understand the human ear can hear from 20Hz to 20,000Hz, 20 being the lowest bass and 20,000 being the highest treble. There are exception, some humans can hear a little lower then 20Hz and some can hear higher then 20,000, and very few have perfect hearing across the entire bandwidth, there may be(and probably are) peaks and valleys in your hearing, unknown to you. It is also important to note that around the age of 30 it is common for hearing to drop off -1 dB above 10k and continue to drop slightly for the rest of your life. This explains why we have different preferences and what sounds good to one may not sound good to another. With that said, be your own judge, don’t let someone else tell you how something should sound to you, listen for yourself and see what you think. Regular CD, known as “redbook CD” only produces 20-20kHz, however, other high-rez digital formats, including SACD and DVD-audio are capable of greater bandwidth and records(vinyl) are capable of nearly limitless bandwidth(though any extreme is probably distortion). Many listeners prefer a speaker capable of higher then 20kHz because they claim the cut off is not abrupt and it is “smoother.” Same holds true to below 20Hz, it can’t be heard by most, but it can be felt, in particular in movies, extreme low frequency information adds a lot to the experience. Getting a true audiophile grade speaker with greater bandwidth on both ends then 20 and 20kHz at ±1 dB is typically very expensive. Many like to employ powered subwoofers to augment the bass, this will add a lot of cost effective bass, but integration is always an issue. I’ve only heard one or two systems in my life where the powered sub was dialed in properly, and they were with megabuck systems that had true full range speakers to compliment them. In short, unless you plan to listen to a format that offers extended frequency response don’t worry about going higher then 20kHz, and buy the lowest bass that you can afford, in a package that you life. Like all aspects of audio there are exceptions to this, and we will cover them in articles to come.
Impedance is probably the most misunderstood aspect of a speaker. Most know it is a measure of resistance, measured in ohms, but what does that mean in your life? Potentially a lot, mass produced speakers over the last 30 years have an impedance measuring from around 1.3-24 ohms, while that is not a huge range, in the world of ohms and home audio they are light years apart. Most modern speakers are in the 3.5-8 ohm range which is much easier to manage. The impedance of a speaker has nothing to do with it’s sound, even the most experienced listener cannot discern a 4 ohm speaker from an 8 ohm speaker by listening. Impedance is important when it comes to matching an amplifier with a speaker, as a general rule solid state amps produce more power at lower ohm ratings, though going too low can be extremely dangerous and tube amps operate better at higher ohms, again not going to an extreme. Most main stream amps and speakers will operate safely in the 4 to 8 range. So don’t base your speaker purchase exclusively on its impedance, that has more to do with amplifier matching to your speaker. There will be an article about amplifiers in the next few weeks and we will touch on this in more detail then. In the mean time don’t get too hung up on this as a spec, it’s much harder to find a speaker that will make you happy then an amp that will work well with it.
Recommended power is usually a broad range of power the manufacturer recommends to power the speaker safely, it is typically measured in watts. However, watts are not all comparable, current, measured in amps needs to be taken into consideration. Also if the amp is class A or class AB or any of the newer circuit designs that are become popular, like ICE or class D. Use this as a broad outline, but don’t base the purchase on this spec, there are very few speakers that present an impossible situation, and this has little to do with it, it is usually a tough combination of impedance and sensitivity that creates the problem.
Sensitivity is how efficient the speaker is, it is usually, again there are exceptions to the rule, measured in dB at 1 watt/ 1 meter using 2.83 volts. Some speakers have different dispersion and are measured at 2,3 or even 4 meters or using higher voltage which makes the speaker seem more efficient then it really is. Most speakers range from the low 80’s to the mid-low 100’s, with the bulk of speakers falling somewhere in the middle. Sensitivity as a whole, much like impedance will have no impact on the sound, per se. Though to achieve high efficiency there are some common designs used that will give a distinct sonic signature; more recently there have been some developments that many manufacturers utilize and have been able to make high 90’s to low 100 decibel efficient speakers. While you shouldn’t base your decision solely on efficiency, it is important to pay attention to because, the impedance and the sensitivity will dictate what type of amplifier will work best and how much power is required.
Due to the length of this article, there will be a series of speaker articles breaking down the 4 major types of speakers, for now I will just mention them quickly. There are conventional dynamic/cone speakers, they use woofers and tweeters and are the most common type of speaker, they come in many configurations, from line arrays(with lots and lot’s of drivers) to simpler two way speakers(just two separate drivers) and many things in between. Moving on, there are planner magnetic/ribbon speakers, these are much less common and very unusual to someone who has never seen them, they are typically tall, wide panels that are fairly thin, some are full planner, while others, usually the more expensive models, use a ribbon tweeter. The most common example of this type of speaker come from a company called Magnepan. A cousin to planner magnetic speakers are what are known as Electrostatic speakers, most often simply called electrostats. These vary greatly from all other speakers in that they have a transformer and need to be plugged into the wall, in addition to having speaker wire connected to them from an amplifier. These range in size greatly from smaller electrostats from Quad, to gigantic speakers from Sound Lab, the most common electrostat manufacturer is Martin Logan. They vary greatly in size, shape, appearance and price. The last unique type of speaker are horns, while not a completely unique technology like the other’s they are unique enough to have their own category. Most are hybrids, they use horn tweeters/mids and dynamic/cone drivers for bass. A horn in itself is a conventional speaker(in simple terms) that uses a horn to increase the overall efficiency of the driving element. I think the most classic example of this is from a company called Avantgarde, though a more common example would be from Klipsch. The reason I feel that horns deserve their own category is that they are clearly unique in appearance and due to their efficiency present a very unique situation when it comes to powering them.
Creating a rewarding audio system is a complex task, and is not something to be rushed into, I realized as I was writing this article that it is difficult to sum up the aspects of even one component in a single article. Before you start purchasing, wait for a few more in this series, or if you have an specific question please post them below. Our next installment will focus on amplifiers, the synergy between the speakers and the amplifier is absolutely crucial and having an understanding of amplifiers will help make your speaker decision much easier.
Part 2 is now posted: Does it come with the amp?
04.26.2008 | Filed under: Cleaning
