Sources are where information comes from. In the case of audio, that means tuners, turntables, disc players, computers, iPods, tape decks, and pretty much any other device capable of playing analog or digital information. In my house at the moment I have a CD player, four iPods, a DVD player, a Blu-ray player, an iMac computer, a digital-to-analog converter, and an Apple TV. All are capable of playing music files, even though some were clearly not designed for that purpose. Who would have thought that a computer could be an audio source, let alone a high-end one?
Sources can be divided into two broad categories: analog and digital. Analog sources read audio information in its raw format, so to speak. Music is naturally analog -- that’s what comes from the recording microphone, and it’s the reason some argue that the best sources are still analog. Those would be turntables and, to a lesser extent, reel-to-reel tape players. The old cassette tape was analog, as was the 8-track tape cartridge. Digital Audio Tape (remember that?) is, of course, digital.
By far the most common and popular digital music machines are CD players. The Compact Disc came along in the early 1980s and popularized digital audio recordings by offering what was trumpeted as pure, natural sound. Early CD players and digital recordings were generally pretty awful and this eventually helped to revive the sales of turntables. In the long run, the CD came to dominate the music world.
Digital sources don’t read music per se, they read data in the form of binary code -- those zeros and ones you’ve heard about. Since our ears and brain can’t process digital information, what the player reads has to undergo conversion from digital to analog -- either inside the device (e.g., a CD player) doing the reading, or externally (by a dedicated DAC). The conversion is done by chips designed for the purpose. Aficionados of turntables will tell you that it’s in this conversion that the music from digital sources loses its soul.
Amplifiers work by amplifying input signals -- of course. But did you know that what leaves an amplifier is not what entered it? That’s because amplifiers aren’t linear, in the sense that they don’t represent a single progression, as you would get when using a lens to zoom in on something small. Instead, an amplifier duplicates the input signal as a much more powerful version of itself.
How amplifiers do this involves the movement of electrons from one side of a transistor or vacuum tube (the emitter) to the other (the collector) when certain electrical conditions are met. For reasons known only to the likes of Nelson Pass, this process boosts the voltage on the collector side of the transistor, and this is what drives loudspeakers.
That’s all well and fine, but what sorts of things do we need to consider when buying an amplifier?
First, let’s discuss some amplifier terminology. Then I want you to forget it all and focus on what’s important.
When you go into your local audio retailer, you may be confronted by salespeople who want to prove their importance by spouting all sorts of arcane specifications for Amplifier A that make sense only to people like . . . well, like me. But you don’t want to be like me. If you were like me, you’d be sitting in front of your iMac listening to Brahms and trying to figure out how to explain amplifier physics -- something that you "get" but have never had to explain to someone else.
OK, here come the terms: Power output refers to how many watts an amplifier produces -- a number that, in some amplifiers’ published specifications, should be taken with a grain of salt. If, say, Sony says its $399 receiver puts out 100Wpc, they’re talking about a theoretical maximum using a measurement system that no one likes and that many abuse. That 100W rating therefore tells you almost nothing. On the other hand, if an amplifier company such as Bryston says that its 4B SST² model puts out 300W, you can take that to the bank, secure in the knowledge that those 300W are not toxic assets.
An amplifier’s gain is how much an amplifier boosts the signal; that is, it’s the difference between the strength of the signal at the amp’s input and the signal strength at its output, measured in decibels (dB). Going back to that 4B SST²: given a 1V input signal, it offers 29dB of gain. In other words, that means it’s amplifying the input signal about 32 times -- quite a leap. That’d be like a turbocharger turning a Ford Focus into a locomotive.
Bandwidth, or power bandwidth, is the frequency range over which the amp operates. In the case of the 4B SST², its bandwidth is stated as being "less than 5Hz to over 100kHz," or from far below to way above the limits of human hearing.
Input impedance is the resistance (aka load) "seen" by the device connected to an amplifier’s input. An amplifier’s input impedance should always be many times higher than the output impedance of the device it’s connected to, to reduce any parasitic noise that might otherwise flow from a source component into an amplifier, and ensure that the strength of the source signal isn’t diminished by the amplifier’s circuitry.
An amplifier’s damping factor is its ability to prevent the drive-unit(s) of the speaker it’s connected to from making unwanted movements near the driver’s resonant frequency. Everything has a natural resonant frequency: You do, I do, so does my dog and my electric toothbrush. If you look at the specs for, say, the Scan-Speak Revelator 8" woofer, you find that its resonant frequency (fs) is 20.5Hz. In other words, if you were to run signals through that woofer near 20.5Hz, you’d find that the woofer wants to vibrate with the signal it’s being fed, and it wants to vibrate sympathetically with that signal because its natural resonant frequency is 20.5Hz. But it’s the job of an amplifier to make sure that the speaker doesn’t vibrate sympathetically. The higher the damping factor, the better the control. The 4B SST²’s damping factor is stated as being "over 500 at 20Hz."
Distortion is great if you’re a heavy-metal fan, but otherwise it’s not something we like in the reproduction of music. There are two primary kinds of distortion that amp makers refer to on their spec sheets: total harmonic distortion (THD) and intermodal distortion (IM). What’s important here is that you want to see exceedingly low numbers for both. Some say that a THD of less than 1% is inaudible. That must mean that the Bryston 4B SST²’s THD+N (I’ll get to the N) of 0.005% is so inaudible that you’d need a very expensive measuring device to even know it’s there. The N stands for noise, as in anything that isn’t audio signal but that leaches its way into the signal path. The 4B SST2’s level of noise is -110dB at 29dB gain. Put another way, the noise is as low as the dynamic capability of the CD is high, give or take.
The fact is that any good modern amplifier will have low distortion, a more than adequate damping factor, and enough gain to drive speakers with relative ease. Ah-ha, you say, but how do you know you’ve got a good amplifier?
The answer, again, is simple. I’ve said this before, about speakers, and I’ll say it again for amps: If you stick with a company that’s known for making amps, chances are high you’ll get a very good one. Who makes good amps? NAD, Anthem, Audio Research, Ayre Acoustics, Bryston, Bel Canto, Blue Circle, Boulder Amplifiers (better move further into the alphabet) . . . Hegel, Threshold, and Zandén, among others. The list is long, and you find out who’s on it by reading our reviews. As always, listen for yourself and make up your own mind.
OK, there’s a bit more to choosing an amp than that. As I mentioned in my speaker lesson, the sensitivity of your speakers may demand a more powerful amplifier to get performance that satisfies you. If your speakers have a low efficiency rating (circa 85dB), you’ll want a more powerful amplifier. On the contrary, very efficient speakers (90dB or higher) need little power to sound their best. Electrostatic speakers are power-hungry, so you’ll want to match them up with a beefy amp -- to be on the safe side, a couple of hundred watts into 8 ohms.
If you’ve made it this far, you might be wondering when I’m getting to the promised preamplifier section. Good news -- it’s right here.
All amplifiers have or need a preamp of some sort. Sometimes it’s an external box, sometimes it’s an internal gain stage, and sometimes it’s a full preamp that shares the same chassis with the power amp, in which case it’s called an integrated amplifier.
A preamplifier goes in the signal path after a source component and, as its name suggests, before the power amplifier. It does amplify the signal itself, but only a little bit. Basically, a preamp provides an intermediate stage between the low-level signal output of a source device and the relatively high level an amplifier prefers at its inputs. For completeness, a phono preamplifier will comprise a number of gain stages to boost the very-low-level electrical signals generated by a phono cartridge into something that even a preamp can work with.
Preamps are also sometimes called control amplifiers because, in addition to providing a little bit of gain, preamps offer such conveniences as volume controls and source selectors. In a volume control, the input signal is fed through a variable resistive path: when more resistance is applied to the signal, the signal is attenuated and the amplifier is fed a weaker signal, which results in less output from the speakers. Conversely, you increase the volume by decreasing the resistance; the amp gets more signal and the music gets louder.
Should you buy your preamp and amp from the same manufacturer? They prefer it if you do, but it’s not necessary. Companies like Bryston and Simaudio go to a lot of trouble to ensure that their amps and preamps have precisely the same sonic characteristics, and that can be important. But mixing and matching different brands can also result in excellent sound. The trick is to experiment -- or do what I do and buy an integrated amp. It’s so much simpler, and fewer cables, too.
We’ve covered speakers, power amplifiers, and preamplifiers. Next up will be sources. But if you’re sweet on CD players, you might not like what’s coming in Part Five.
. . . Colin Smith
colins@soundstagenetwork.com
Amplifiers are among the simplest of audio components: a signal enters, a more powerful copy is made, and it’s pushed out the back end. Of course, there’s way more to the story! Designing amplifiers is probably as much art as science, and as with loudspeakers, a good engineer can "voice" an amplifier to give it a particular sound. But while there are many ways to design an amplifier, all follow well-established design principles that define how they operate.
Class warfare
All amplifiers adhere to design parameters that fit within specified "classes," characterized as class A, class AB, class B, class D, etc. In the simplest terms, these classes identify how an amplifier goes about amplifying and how efficient it is in its operation.
Class-A amplifiers are characterized as having output stages that are always "on" in the sense that an individual output device -- a transistor or vacuum tube -- is responsible for amplifying the full amplitude of an incoming signal. So what is amplitude? Well, think of an ocean wave. A wave’s amplitude is its height above a fixed horizon plus its depth below, so a wave that rises and sinks 1.5' past a fixed horizon has an amplitude of 3'. Audio signals are waves, too, and their amplitude is measured as a voltage above (positive) and below (negative) a zero point (the horizon).
A class-A amplifier’s output device, then, is designed to stay on through the full signal amplitude -- from all the way positive to fully negative and back again. Another way of expressing this is to say that the class-A device remains on for a full 360-degree amplitude cycle because it’s responsible for amplifying both the positive (180 degrees "up") and negative (180 degrees "down") halves of the signal. The corollary of always being on is that, when the amplifier is powered up, a class-A device is never off.
This "always on" characteristic explains why class-A amplifiers tend to produce a lot of heat. A small room housing a big class-A amp is a hot place if there’s no air conditioning. In solid-state class-A amplifiers (ones that use transistors versus vacuum tubes) there are substantial heatsinks, which draw heat off of output transistors and prevent them from self-destructing. Interestingly, the heat coming off a class-A amp represents about 65% of the total energy it consumes. Put another way, class-A amps convert only 35% of the electricity they consume into audio output. As you might expect, because it wastes so much power a class-A amplifier needs a massive power supply to feed it. In a powerful class-A amplifier like the Pass Labs XA160.5, which produces 160W into an 8-ohm speaker load, the power transformer is huge and might account for almost half the amplifier’s 150-pound mass.
Class-B amplifiers feature output devices that conduct only during 180 degrees of amplitude so, unlike in a class-A amplifier, a class-B output device is off for half of the amplitude cycle. A class-B output stage is referred to as having a "push-pull" configuration, with the positive device "pushing" and the negative "pulling" the signal along. As a consequence, while a class-A amplifier can conceivably use a single output transistor or tube to amplify the full signal wave, class-B amplifiers require two output devices at a minimum, one positive and the other negative. Interestingly, though a class-B amp requires twice the number of output devices as a class A, because half the devices are off at any given time a class-B amp can be up to 78.5% efficient, a vast improvement over class A in that regard.
Between class A and B is class AB, a hybrid of the two designs that configures its output devices to be on between 51% and 99% of the time (50% being class B and 100% class A). My reference Simaudio i5.3 integrated amplifier is both a class A and class AB amplifier, with its first 5W of output being fully class A and the remainder of its 85W output being class AB. As expected, class-AB amplifiers are half way between class A and class B in electrical efficiency.
Class-D amplifiers are the coolest thing in amplifiers these days, and not just because they’re very energy efficient. These newer-tech amps are often erroneously called "digital amplifiers" but in fact they are fully analog devices in that the input signal is not digital. Class-D output devices get the digital moniker because like a digital audio signal they are either fully on (a digital "1") or fully off (a digital "0"). This mode of operation spawned a more accurate name for class D as "switching amplifiers," with the switch being a transition from fully on to fully off. But how can an amplifier produce an uninterrupted audio signal if it’s off half the time? The answer is that class-D amplifiers and their associated power supplies switch really, really fast.
ICEpower, a Bang & Olufsen subsidiary, is one of the big names in class-D design, with over 70 audio manufacturers using its amplification modules. ICEpower’s 250ASX2 module, a 250Wpc device that, power supply and all, is about the size of an average postal envelope, switches on and off between 90,000 and 600,000 times per second. Since class-D amplifiers don’t produce any heat when they’re off, class-D amps operate much more coolly and efficiently than other amplifier classes. In fact, class D can be more than 90% efficient, and because so little power is wasted as heat, class-D amps can get away with tiny heatsinks or even no heatsinks at all. They can also do quite well with power supplies that are a fraction of the size required in a class-A design. Smaller power supplies make for lighter amplifiers, so while a great-quality class-A amplifier with a couple of hundred watts of output per channel can weigh 60 to 260 pounds -- a majority of that being its power supply -- a comparable class-D amp might weigh five pounds.
Interestingly, the svelte nature of class-D amps seems to have led to a weighty problem for high-end-audio manufacturers. Traditionally, high-quality audio amps are heavy beasts, but class-D technology allows amplifiers to be small and light. Unfortunately, small and light translate to cheap for some consumers. Perhaps to address this stigma, manufacturers have resorted to making exceptionally heavy cases for their class-D modules, with the additional casework making up a lot of the weight differential. By way of example, Jeff Rowland’s ICEpower amplifiers feature casework that more resembles an aluminum tub than a traditional chassis. With walls about an inch thick all around, this casework is more fallout bunker than chassis, but it adds a lot of the heft that some buyers demand.
Thick cases aren’t just about weight, though, as some would argue that class-D amps need such housings because with their high-frequency switching comes high-frequency noise pollution that must be contained. This was the case during the technology’s early days, and it likely still is with some cheaper designs. But companies like NuForce have shown unequivocally that high-end sound can come from small, light amplifiers that give up very little but weight and heat dissipation to their more conventional cousins.
It’s actually the whole idea of switching on and off that some say qualitatively sets the different amplifier classes apart. According to their argument, class-A amps sound best because they never switch and therefore produce no switching noise. Class-B amps switch, but they do so far less frequently than class D, and some therefore believe them to be inherently superior to class D while remaining inferior to class A. Real-world experience reveals that there are no absolutes. The truth is that there are excellent amplifiers -- and real dogs -- in each performance class. As always, a product’s specification sheet should be a guide; what really matters is how an amplifier sounds to you.
Next Installment: "How Amplifiers Amplify and Just What the Heck Is a Preamp?"
. . . Colin Smith
colins@soundstagenetwork.com
I’m subbing for GoodSound! senior editor Colin Smith this month because he had to take a month off his audio duties to attend to more pressing matters. I’m fine with that -- I’m always happy to express my opinions about affordable high-performance audio, which is one of my passions. I love helping people find great, modestly priced gear that performs as well as, if not better than, equipment that costs much more.
The impetus for this article came easily: Today as I walked through a store, I spied a pair of speakers that looked attractive and seemed interesting. I stopped and listened. They sounded awful. Despite their good looks and interesting appearance, they were, for all intents and purposes, crap. I couldn’t help but think that Someone is going to get conned into buying these heaps just because of their looks, and will possibly think that this is how a good speaker is supposed to sound. How can I keep people from buying speakers like these, and steer them toward something that actually sounds good?
The best way to avoid buying crap audio gear is to know a lot about the subject. Know the market inside out by reading reviews and listening to as many products as you can. GoodSound! and the other SoundStage! Network publications are great places to find those reviews, and you’ll likely find a few stores in your area where you can audition gear.
You can go further: Learn about the underlying technology on which each category of component is based, and perhaps even conduct your own battery of tests. When I began getting seriously interested in loudspeakers, I learned all I could about speaker design and testing methodology. As a result, I know the parts that go into speakers, I understand how they work, individually and together, and I know how they can be tested to determine if they’re good or not. Do-it-yourselfers might go a step beyond this and try building their own components.
But not everyone wants to go to such lengths to inform themselves about something they want to buy; most just want to go to the store, buy something, and feel confident that they’re bringing home a good product. In short, they want to avoid buying crap.
The easiest way for me to steer someone straight is to single out by product type some brands that I know produce good stereo products throughout their lines, and that rarely if ever sell something that I would consider crap. Knowing these brand names can at least steer shoppers in the right direction. (Note that I’m limiting this to two-channel components; perhaps a similar article on home-theater equipment will surface in the future.)
There are many great speaker brands on the market, and my list is far from exhaustive -- it’s unavoidable that I’ve omitted some good brands. But when it comes to building good-quality, affordable, high-performance speakers, the brands I’m most familiar with and can easily recommend shopping for are: Paradigm, PSB, Axiom Audio, Aperion Audio, Polk Audio, Definitive Technology, Ascend Acoustics, KEF, B&W, Amphion, Monitor Audio, and Focus Audio. Not every speaker from every one of these brands will suit your needs or your budget, but I’m confident that if you find a model from one of them that you feel is suitable, you can be confident that it won’t be crap.
The number of electronics manufacturers providing high-quality, affordable preamplifiers, power amplifiers, and integrated amplifiers is far smaller, but I feel comfortable recommending certain brands for their general high quality, affordability, and established track records spanning years, sometimes decades. NAD, Anthem, Cambridge Audio, Rotel and Arcam are the staples in these regards; their product lines are vast and varied, and their products’ performance ranges from good to outstanding. The prices of another brand are quite a bit higher, but if people can stretch their budget that far, I like to recommend Bryston. Their entry-level gear costs quite a bit more than the entry-level products of the four other brands listed, but Bryston has long been my benchmark for cost-no-object-type build quality and performance for what can still be considered a reasonable price. And they back their components to a degree few other manufacturers do -- most Bryston products come with a 20-year warranty. For many, this means that they can be considered very long-term purchases.
Recommending a digital source these days is difficult: CD is on the way out, and computers streaming digital music files are in, as are other digital source components, such as the Apple iPod and media players like Logitech’s Squeezeboxes. Because the options in this area are so varied, it’s difficult to recommend specific brands, but I can give you some direction.
If you still want to play CDs, some of the best affordable players I’ve come across are from NAD and Cambridge. In fact, I now use NAD’s C 565BEE, and find it superb. If you’re going to use your computer as a source, I’ll first address the topic of file formats, which is as important as the playback equipment. I don’t recommend playing low-resolution MP3 files; the format is lossy and compressed, which results in inferior sound. Instead, use a lossless format like WAV, FLAC, AIFF, or Apple Lossless, all of which support CD-quality resolution or better. I also highly recommend buying a top-notch soundcard with a high-quality digital-to-analog section -- or, better yet, an external DAC that can support higher sampling rates such as 24-bit/96kHz, or even 24/192. Don’t rely on the cheap stock soundcards that come with most computers -- they’re usually crap, which is what we’re trying to avoid using. I don’t know the market of optional soundcards well enough to recommend brands, but I do know DACs. High Resolution Technologies makes a series of inexpensive DACs they call Music Streamers that seem very good. And Simaudio is now bringing the performance of their cost-no-object digital sources within reach of GoodSound! readers -- Colin Smith reviewed their Moon 300D DAC and loved it. It’s worth saying that most CD players, while not DACs per se, can be used as DACs because they have digital inputs. Lotsa options.
Though there’s a lot of talk these days about the vinyl resurgence, I think its scope has been exaggerated by the media and by some wishful thinkers. Still, there are no doubt plenty of people today who want to play LPs, old and new. If I were shopping for an affordable turntable right now, I’d first look to three well-established brands: Pro-Ject, Thorens, and Rega. More than likely, any of their models will come with a tonearm, but you’ll have to supply your own phono cartridge.
Finally, cables: interconnects, speaker wire, power cords. A longtime audiophile favorite is DH Labs, and for good reason: Their Silver Sonic brand offers a wide range of cables (speaker, interconnect, power) that are very fairly priced for the quality. Even if you buy DHL’s most expensive stuff, it’s still a good deal compared to what many audiophile-grade cables cost. And if you’re thinking of getting audiophile-grade power cords, I like Essential Sound Products (ESP) for their good quality and reasonable prices. Last but not least, here’s a name not well known to audiophiles, but whose cables I’ve found superb: Supra, a brand of Jenving Technology, based in Sweden. Check out their extensive catalog to see all the products they make. I’m using a Supra HDMI cable now, and it’s outstanding.
I can’t guarantee that any system assembled from the product lines of the companies listed here will be your ticket to sonic nirvana. Building a great audio system is more than just hooking up some components -- there’s a certain synergy involved. But I’m confident that if you do buy products made by these companies, they won’t be crap, and that you’ll greatly increase your odds of building a very good stereo system. Take these lists of brands, go shopping, listen for yourself, and see if you don’t agree.
. . . Doug Schneider
das@soundstagenetwork.com
Shopping for loudspeakers can be a daunting experience. More often than not, audio shops will display speakers in a listening room where the ones you’re interested in will be among many other pairs, and few of those will be optimally positioned for proper audition. Then there’s the question of electronics. Does it matter if an inexpensive speaker is hooked up to electronics that are far more expensive than the gear you have at home? And what of specifications and materials? How important are these elements?
The answer is that everything matters to a certain degree. But even before we consider these things, the central issue is why you want to replace your existing speakers. What is it about them that you like and don’t like? Are they simply worn out? Do they lack bass, treble, or midrange? Knowing what it is about your old speakers that has you thinking of new ones is important to finding a satisfying replacement pair. With those factors in mind, let’s look at some technical parameters.
Specifications that should attract some attention are a speaker’s sensitivity rating, given in decibels; its power-handling capabilities, expressed in watts; and its impedance, represented in ohms. Sensitivity is a consideration if a speaker will be driven by a lower-powered amplifier -- let’s say of 50Wpc or less. The lower a speaker’s sensitivity, the more power it requires to achieve a given sound-pressure level. A speaker of 84dB sensitivity will therefore need more power to produce a given output than a speaker of 94dB sensitivity. While the 10dB difference might not seem like much, they’re a world apart. A 94dB speaker can be driven by low-power tube amps that might produce 10Wpc. Cranked up to its maximum volume, that same amp would get very little sound out of the 84dB speaker. The lesson here, then, is to match speaker sensitivity to the amplifier they’ll work with. A lower-powered amplifier needs a more sensitive speaker, while an insensitive speaker needs more power.
Impedance is to alternating current what resistance is to direct current, and while a lower sensitivity number means a speaker needs more power for a given output level, a lower impedance number also means the speaker will demand more current from the amplifier. This explains why some amplifier designs can double their output power into a lower-impedance speaker, say 100W into 8 ohms but 200W into 4 ohms. This is because a 4-ohm speaker presents half the electrical resistance to an incoming signal than an 8-ohm speaker. The power boost isn’t always double, and it depends largely on an amplifier’s ability to deliver more current into lower impedances, but generally speaking a 4-ohm speaker will get more power out of an amplifier than an 8-ohm model. Not incidentally, the vast majority of loudspeakers will be either 4- or 8-ohm impedance. Lesser amplifiers may have trouble driving impedances below 4 ohms because they can’t supply enough current. Try to stick with speakers with at least 4-ohm impedance or higher.
Power-handling capability isn’t much of a factor in most cases because most speakers can handle the 50Wpc to 100Wpc power output that the majority of amplifiers produce these days. Take care with physically small speakers, though, as they generally won’t do well with a super-high-powered amp: a number of speakers get fried because the amp they’re connected to is too powerful for them. This would be a good time to point out that most integrated amplifiers or receivers don’t have to be turned up all the way to achieve maximum output; many get there at about the one o’clock position on a rotary volume dial. Note that a lower-sensitivity speaker will probably have a minimum amplifier power rating. That minimum number often seems low to me, and I’d never recommend hooking up a speaker with a minimum recommended power level to an amp of that output. So if the speaker says “minimum 20W amplifier power,” think 40W. A speaker can also be damaged by too little amplifier power, whereby the amplifier is overdriven and distortion from the amp damages the speaker’s drivers, most notably the tweeter.
Armed with new knowledge of speaker specifications, you might feel ready to head to the audio shop, but let’s not rush into things. Since the store you visit likely won’t have your amp and audio source connected to the speakers you want to hear, we have to know something about the sonic character of your equipment and of the equipment the store uses for demos. The first step should be to call the shop and find out what equipment they’re using and whether you can bring yours in for the speaker try-outs. Bringing your own gear isn’t always feasible, but you can mitigate the disadvantages of not using your own equipment by reading some reviews.
That may sound a little self-serving coming from an audio reviewer, but an experienced reviewer will have heard a lot of equipment and can offer a clear assessment of a product’s merits. Pay attention to the audio adjectives the reviewer uses, and look for a speaker that offsets or even accentuates the characteristics those adjectives describe.
If a particular amplifier is known to produce deep, prodigious bass, for example, you should avoid a speaker that has loose, tubby or overblown bass, because the speaker will ruin the amp’s good intentions. An etched amplifier will probably put too much emphasis on the treble, so pairing a sparkling tweeter with it might sound like fingernails on a blackboard. But an amp that’s a little light in the bass might work well with a speaker that overemphasizes it a little, while a dull tweeter could tame that etched amp.
Knowing a thing or two about the equipment you’ll hear, then, can go a long way to improving the odds that the new speaker will work for you at home. So if the audition amp is known to have a forward midrange and that’s what you hear from the speakers, one possibility is that the speaker is fairly neutral, as it’s not altering the sound coming from the amp. If your amp has no midrange issues, the speaker probably won’t bring any into the mix.
Now you can head to the store. When you get there, remember who’s boss. You don’t need anyone telling you what sounds good -- figuring that out is your job. Salespeople might be inclined to steer you away from the speaker you want for something with a better profit margin, perhaps on the thin justification that it has better design or materials. But stick to your guns and listen to the speakers you want to hear, not the ones they might want you to buy. But be sure to listen to alternatives while you’re there. Just make sure that you listen to your speaker’s direct competitors, not something that costs twice as much.
Make sure that the salesperson moves the speakers you want to hear into a reasonable listening position that mimics yours as closely as possible. Speakers that are 9' apart in the store won’t sound the same when they’re 6' apart in your home. You should also make sure the speakers are as close to the front wall in the store’s listening room as they’ll be in your setup. Putting a smaller speaker too far out might make it sound thin and could be a salesperson’s attempt to slide you into buying something bigger and more expensive than you want. As for cables, in my experience most audio shops don’t use exotic speaker cable in their audition rooms, but if the cable costs more than the speaker, get them to swap it for something reasonable.
Bringing music you’re familiar with to the audition is definitely a best practice. Chances are good that the speakers you’re going to hear will alter the sound of a given recording, so you want to make sure you like the results. You also want to make sure you actually hear a difference! There’s not much point in buying new speakers that aren’t any better than what you’re replacing. And while you’re listening, don’t rush or be rushed. Sometimes changes will smack you in the forehead; other times you’ll have to listen for a while to pick out subtle differences. The slight changes are no less significant than the obvious ones, so don’t abandon your audition of a particular speaker if it isn’t wowing you after 30 seconds.
At this point you’re on your own with your particular likes and dislikes. Again, the only thing that matters is that you like what the speaker is doing. The salesperson’s input is largely irrelevant. All you really want to hear from them is that you can try the speakers at home and return them if they don’t work for you. Some dealers might shy away from a good return policy to avoid accommodating buyer’s remorse, but if you take your sweet time selecting a speaker and show the salesperson you’re sincere, things may go your way.
Once you have your new speakers at home, prepare for some disappointment. Speakers are mechanical devices, and they require some break-in to sound their best. No serious speaker manufacturer claims that hundreds of hours are necessary to achieve optimal performance, and some say you’ll need as few as five hours. But my experience is that it doesn’t take long. A pair of speakers I’m reviewing now sounded shouty and bloated just a few hours ago when they were fresh from the box, but half a day’s worth of mid- to high-volume music has settled them in nicely.
This lesson wouldn’t be complete without a mention of online speaker sales from companies like Axiom and Aperion. It’s pretty hard to audition speakers that you can’t find in a local brick-and-mortar store, but direct sellers should definitely be contenders -- you’ll simply have to rely more heavily on reviews.
The difference between your Paradigms and PSBs, and your Aperions and Axioms, is that the former were founded well before the Internet became a way to sell directly to consumers, so those companies have developed extensive dealer networks and a huge base of customers who expect to find their latest wares at the local audio shop. The way these companies distribute their products, then, has no effect on their quality of design or performance. The advantage of direct sellers is that you can audition their products in your home, with your equipment. You can also have speakers from two or more companies in your home at the same time, competing head to head for your business. Just be aware that the speakers you don’t want to keep might have to go back at your expense, and packing and shipping speakers can be a real pain!
Next month in Audio 101 Part Three, we’ll discuss the ins and outs of amplifiers.
. . . Colin Smith
colins@soundstagenetwork.com
It drives me crazy when I read articles that use technical terms as though the whole world knows what they mean. Just what does a car do when it understeers? Beats the heck out of me, but you won’t find a road test that doesn’t mention it. And as it turns out, we’re hardly blameless in this regard.
In hindsight it should have been obvious that GoodSound! attracts both budget-minded audiophiles and people who are new to the hobby or who just want to assemble a decent audio system. And it’s the latter group we’ve been letting down.
As educators, we have a responsibility to make sure our readers understand what we’re talking about. So starting now and over the coming months, this column will be dedicated to explaining commonly used audio terms that appear in our reviews. We’ll also go into the weeds and talk about what we think are important considerations in assembling an audio system. While not meant to be exhaustive, this series of columns will arm you with enough information to see through salesperson bafflegab and make informed buying decisions.
Loudspeakers
The single most important parts of any audio system are its speakers. Choosing the right speaker can ratchet up the enjoyment factor, while a poor choice can ruin a system’s sound. The good news is that if you stick with speaker makers that are both engineering- and listening-driven, you’ll be hard pressed to find a real dud. But before we discuss how to match speakers to electronics and your room, let’s get some basic terminology on the books.
The drivers
The number of ways (two-way, three-way, 3.5-way, etc.) refers to the number of frequency segments -- divided by crossover points -- found in a given speaker. A two-way will feature a woofer(s) and a tweeter, and a three-way will add a midrange. A 3.5-way will probably have a tweeter, a midrange, and two woofers, one to handle the full bass spectrum and the other for the very lowest frequencies.
Driver (aka transducer): the dynamic component of a loudspeaker that vibrates in sympathy to an incoming electrical signal. There are three main types of driver: woofer, midrange, and tweeter. These are usually in the form of a cone (woofer, midrange) or a dome (tweeter).
Woofer: the largest single driver found in any speaker. A woofer is designed to produce bass frequencies, and its diameter is usually indicative of the bass energy and depth of frequency it can reproduce. This means that the bigger the woofer, the lower and louder the bass, all other things being equal. A subwoofer reproduces frequencies at the bottom of the bass range, usually down to the 20Hz level, where bass is felt rather than heard.
Midrange: the middle-sized speaker that’s most often associated with reproducing tones in the midband frequencies, such as those making up the human voice. A typical midrange might be 2" to 6.5" in diameter and cover from 300Hz to 3000Hz.
Woofer and midrange drivers can be made from a variety of materials that must be both light and stiff. Light materials are easier to start and stop, and stiffness is necessary to reproduce frequencies with low distortion. Common woofer and midrange cone materials are polypropylene, treated paper, and even carbon fiber. Many speaker makers use a polypropylene composite cone with other materials, such as ceramics or glass fiber, added to improve performance.
Tweeter: the smallest driver, designed to reproduce the highest frequencies, from perhaps 2000Hz to 40,000Hz, beyond the limit of human hearing. Tweeters may be hard domed (made of metal), soft domed (made of fabric), or ribbons (a folded metal ribbon).
Tweeters may be made of materials like aluminum, titanium, silk, beryllium, or diamond. The latter two are generally considered to be the best materials for tweeters, but they are expensive and hard to work with. Many speaker makers coat metal-dome tweeters with another metal, such as gold over aluminum, in order to tweak performance.
The cabinet
Acoustic suspension (aka sealed box): an air-tight speaker enclosure. Generally, proponents of a sealed-box design tout the speaker’s ability to respond quickly to inputs, resulting in what might be described as a "fast" speaker or one that "transitions" between frequencies or energy levels quickly. On average, an acoustic-suspension speaker will achieve its speed at the expense of low-bass reproduction.
Bass reflex (aka ported enclosure): a box that, through an open port, allows the driver’s back wave to reinforce bass response. Ports may be mounted on the front, back, or bottom of an enclosure. Where there are two or more ports there’s usually more than one woofer in use, and each woofer may be housed in its own sub-enclosure inside the speaker.
As with woofers, size matters when it comes to speaker cabinets. Generally speaking, the larger the cabinet, the deeper the bass the speaker can reproduce. Floorstanding speakers therefore tend to be better with bass than stand-mounted speakers.
Another term often seen in speaker reviews is baffle. The baffle is the front face of the speaker cabinet, on (or through) which the drivers are mounted. A baffle should be stiff and sturdy, as its goal is to allow the drivers to vibrate without losing their energy to the cabinet.
The crossover
Think of a speaker’s crossover as the acoustic equivalent of a railroad junction. As its name implies, a crossover is designed to shunt certain frequencies to the type of driver designed to reproduce them. Crossovers are necessary in multi-driver speakers because sending the wrong frequencies to a certain driver type, such as heavy bass to a tweeter, will tend to damage that driver. Crossovers use three primary components: resistors, capacitors, and inductors. Through various electrical principles, these components filter out certain frequencies and allow others to pass through.
Binding posts
Many people have asked me what "five-way binding posts" are. Well, they are the terminals that speaker cable is attached to at the back of a speaker. Binding posts have a central stem, and over that stem is a nut that can be tightened to hold cable in place. As for the "five ways," the cable can be attached as bare wire through a hole in the post, accessible from the top (first way) or bottom (second way). A spade connector can also be used between the nut and the stem from the top (third way) or bottom (fourth way). Finally, a banana connector can be inserted into a hole in the nut (fifth way). Posts are usually made of gold-plated brass, which is used for its good electrical connectivity and its strength. Some manufacturers use pure copper, but it’s softer than brass and can break under strain. The same goes for silver.
Next month I’ll talk about shopping for speakers and matching speakers to components.
. . . Colin Smith
colins@soundstagenetwork.com
Your correspondent recently found himself in London’s Canary Wharf, where billions are made and lost every day and where a host of British motorcar companies recently showed off their wares. They wouldn’t let me drive them, but these British cats sure know how to set up a car stereo. Here are my favorites:
Naim: Bentley’s Continental GT is a favorite of the rapper set, and not just because it comes factory equipped with major bling. British audio icon Naim was commissioned to create an entertainment system worthy of a Bentley, and it delivered! The GT’s stereo uses an 1100W, 13.2-channel amplifier and a DSP processor featuring eight modes and a dynamic EQ that alters tone controls to compensate for ambient noise. The cabin has 13 drivers and two subwoofers situated throughout. And the sound? I don’t know if car audio gets any better. The good news is that the audio system is free . . . with the purchase of any $182,500 GT (USD).
Bang & Olufsen: Aston Martin’s new Rapide is a design masterpiece, so it seems fitting that Bang & Olufsen, a company known for industrial design, set up the car’s hi-fi. Featuring 1000W of ICEpower amplification, 15 speakers, and high-def seat-back video screens, the Rapide has an entertainment system that puts most home theaters to shame. Cool features include what I hoped were Q-inspired laser cannons, though they turned out to be two B&O Acoustic Lens tweeters that rise from the dash. There’s also a DSP system that senses how many people are in the car and where they’re seated. Perhaps the most gee-whiz feature is that the system lets the driver focus the sound in the front, in the rear, or just around the driver. The latter effect is the most amazing DSP I’ve ever heard, and it makes the passenger-side speakers feel a heck of a lot closer. Yours to enjoy for a paltry $215,000.
Bowers & Wilkins: British speaker maker Bowers & Wilkins (B&W) plays a big part in separating the new Jaguar from its competition. The XJ sport sedan can be fitted with a 1200W multichannel amp, 20 B&W speakers, two 8" backseat video monitors with touchscreen remote (natch), an Audyssey MuItEQ system, and a (surprisingly small) 30GB hard drive to store tunes. Though not quite on the same level as in the higher-end cars, the B&W system was massively ahead of, say, the audio that comes with a BMW 5 Series. A relative bargain at $2200, plus $72,500 for the car.
. . . Colin Smith
colins@soundstagenetwork.com
The SoundStage! Network’s extensive coverage of High End 2010 in Munich, Germany wasn’t entirely devoted to uber-expensive audio. Here are five low-cost gems worth getting excited about:
Furutech’s cleverly named Le Mans 24-bit all-in-one DAC-60Wpc integrated amplifier is first on my list. Considering that it’s adorned with Furutech’s acclaimed RCA, XLR and speaker connectors, if this shapely product sounds half as good as it looks the Japanese manufacturer will have a hard time keeping up with demand. Could the $1800 Le Mans be the killer budget component of 2010?
Not if Anthem has anything to say about it. The electronics sister to Canadian loudspeaker powerhouse Paradigm, Anthem has slowly expanded its product line from top-of-the-line A/V processors to include power amps and an integrated two-channel amplifier that wowed our Philip Beaudette. Now Anthem is combining its processing and amplification expertise into one box in the form of the MRX A/V receiver series. Expected to retail for around $2000, the MRX 500 is the first of a planned family of receivers fitted with HDMI 1.4 and, astonishingly at this price point, Anthem Room Correction, the most advanced room-correction system I’ve ever experienced. Other receiver makers must be losing sleep.
Remember Boston Acoustics? Like so many other venerable speaker brands, Boston went off the rails for a while. But if the company’s new RS 334 floorstander is any indication, Boston is back, baby. Tall, slim, and packed with five drivers, the $2100-per-pair RS 334 should appeal to the lifestyle crowd as much as audiophiles looking for a diminutive but full-sounding speaker. But whether the Boston Acoustics brand can still attract a customer willing to spend $2000 on speakers remains to be seen.
Pro-Ject’s Box series started out with a couple of inexpensive phono preamps, but it has multiplied like atomic rabbits into a family of 30-some products. Want a small receiver, DAC, CD player, power amp, or even a turntable speed controller? Pro-Ject has a Box for you -- all from about $100 to $700.
Elac is a terrible name but a good loudspeaker brand. Granted, some of its designs have the aesthetic of a German disco circa 1989, but the stand-mount BS 182 exudes class and refinement. Coming in at about $1300 a pair, the BS 182 features Elac’s proprietary JET Ill ribbon tweeter and a bottom-mounted port that fires into a base plate. In practical terms, putting the port on the bottom allows for more placement flexibility than a rear-ported enclosure. Design-wise, the bottom port means the lovely front baffle isn’t blighted by a big hole. It would be great to see Elac come to North America, where it could be the next Amphion.
. . . Colin Smith
colins@soundstagenetwork.com
Stagnant industries die. Innovators set the pace and map the future. We've always known that at GoodSound!, the Web's preeminent site for everyman audio reviews, opinion, and news. We -- meaning the SoundStage! Network, under whose umbrella Goodsound! operates -- were among the first specialty-audio publications on the Web, and we're now the biggest and most established of them all.
A few things have always set GoodSound!, as well as the larger SoundStage! Network, apart from other audio publications. Foremost among these is that we care about the content we produce. Our writers have more than a passing familiarity with the rules of English grammar, and we employ professional proofreaders and copy editors to ensure the readability of our content. We also offer more coverage of the affordable end of the audio spectrum than anyone else, because that's where our readers spend their money. We know that you have options when it comes to review sites, and we want to reward your choice with content that's accurate and relevant.
Readers familiar with our Soundstage! Network sister publications will have noticed that we're in the process of reinventing ourselves once again. We’re pushing the envelope with image-based content, and we're carefully massaging how we write reviews to keep them snappy and current. GoodSound! is the latest family member to undergo this transformation, and the site you're viewing represents the coolest, baddest, and most relevant home entertainment site on the Web, bar none.
That's right -- I said "home entertainment." As much as we're a bunch of die-hard two-channel audio guys, we recognize that home entertainment convergence isn't coming; it's a reality. As I write this, I'm streaming audio from a PC upstairs through my wireless home network to another computer connected to my main two-channel system. I'm controlling all of this from an Apple iPhone linked to the same network. I could be doing the same with HD video content from my laptop to any number of video-streaming devices capable of connecting to my plasma TV. As gee-whiz as this setup might seem now, in a couple of years it will seem quaint. These technologies are so new that we can't yet imagine where the limits may lie. But we're darn sure going to find out.
As keen as we are to highlight this brave new world to our readers, we have no intention of abandoning or even circumscribing our coverage of good old-fashioned two-channel-audio reviews. But as products and the home entertainment environment evolve, we'll be seeing a lot of crossover that will blur the lines between what we used to think of as stereo, multi-room audio, and home theater. The distinctions can be hard to make now, and in just a couple of years there may be none.
Join us on this voyage of discovery. We can't say where the future will take us, but we know that as audio has progressed over the past 15 years, we've never deviated from our central mission. Count on us to help you navigate the maze of products and technology coming our way, and as always, rely on this site to learn where to find really good sound!
. . . Colin Smith
colins@soundstagenetwork.com
At least once a week, I’m asked by a reader to recommend an electronic component, a cable, a loudspeaker -- or all three at once. Being asked such questions is gratifying; it tells me that people are reading my reviews and take my assessments seriously enough to want my advice. But while that advice is freely given, it isn’t something I dispense without serious consideration.
I’ve taken a lot of time to assemble my own system, not least because new review products come along and cause me to defer any purchase a bit longer by giving me more choices. That was the case with my search for a reference loudspeaker, which took me about two years to complete. Part of the problem I faced was an embarrassment of riches: there are so many great speakers being made today that it seemed an impossible task to choose just one.
When choosing a new component for my system, I do as most readers do: ask others for advice, scan the market for what’s available, and, ultimately, rely on my own counsel. In the last, I’m fortunate in having already reviewed a lot of the products. In addition to those things, I factor in the company’s reputation, and the expertise of the people who designed and made the product.
Certain industries attract romantic dreamers -- airlines and car manufactures come to mind -- who have more capital than business sense. Audio is no exception. Dozens of companies have come and gone in less time than the average product cycle at such stalwart firms as Bryston, Paradigm, and McIntosh. Keeping that in mind, I tend to shy away from companies whose product lines have little or no depth, that are very new, or that seem to be selling their products at prices that can lead only to financial ruin. After all, bankrupt companies don’t honor warranties -- and they make selling their gear in the used market that much more difficult.