Electronics (Audio - Home)

Buying Home Audio Equipment: Decoding the JargonThere is a multitude of home audio equipment available on Ebay, and some of it is a whole lot cheaper than what you can buy in a shop; the question is: is what I'm buying a great deal or a lemon?This can be said of any purchase on Ebay, but with electronic equipment the quality of your purchase can vary astronomically.The thing is, you don't need to be an electronic expert to know how to make sure your purchase is worth it.GenerallyAny audio equipment you buy will have an element of risk associated with it's quality, however there are some very basic rules to follow when buying any item, and I've noticed these rules are even more applicable when buying electronic equipment:1. Obviously check the seller's feedback rating. Ebay provide us with this service for a reason: it stops you from being ripped off! If the seller has no rating but has a lot of items listed then it's likely they've newly registered to get away from their bad rating. This may not be so, but remember: you're always taking a gamble if your seller has no credibility.2. Check the item location. Especially with electronics there are a lot of international sellers, some of which are genuine some of which are not. The reason for a large amount of international sellers is that there is a lot of cheap electronic equipment available internationally. Some sellers will use this to make a big profit for themselves and a big saving for you, but others will exploit this and allow you to send your money internationally, then just disappear. If you are buying from an international seller, I stress the first point even more: credibility ratings are extremely important.3. Check the postage cost. I know many people (including myself!) who have fallen for the temptation of a cheap piece of audio equipment and just simply forgot to check how much the postage is. Even for domestically posted items there are many sellers out there who charge over a hundred dollars for a very small item. If you're in doubt about how much an item should cost spend an extra 10 minutes looking up postage costs for Australia Post.4. Get insurance!!! Electronic items are fragile, and require careful handling. It's a sad fact that our postal service does not always take care of items, even if they have "fragile" written all over them. I was home once when an Australia Post van pulled up in my driveway, and I saw them get a set of speakers for me from out of the back of the van: the box was upside down, extremely dented, and balanced on an angle with other boxes lying all around it! Needless to say, my speakers were extremely damaged - they looked like someone had taken at them with a hammer! LuckilyI had postal insurance and the seller posted me out a new set quick-smart. Any credible seller will usually offer the option of postage insurance - take it. Don't risk hundreds of dollars of equipment to save a few bucks.AmplifiersSome people don't know this, but if you're buying a set of speakers (for say, your home entertainment system)the most important thingis yourneed for a goodamplifier (or AV receiver as they're commonly referred as). This is just a "middle man" that: usually has a radio receiver (in some caseshigh definition), a pre-amp that takes in all of your audio and visual signals and routes them to their proper place and a built in multi-channel amplifier that decodes and sends your sound to each of your speakers (these days usually 5.1, 6.1 or 7.1 surround sound).There are lots of cheap amplifiers on Ebay, but amany of them are absolute rubbish. The first thing to note is that if you're buying a "brand name" amplifier then you're generally going to get a good buy - brands such as Sony, Yamaha, Kenwood, Rotel, Marantz and a few others have a reputation to hold up. However, there are some "brands" sold on ebay that sound like brands you know, but have a letter different here or there. This is why whenever buying audio equipment you must look at the specs.For an AV receiver don't just look at one specification - look at all of them as a package, because really, an AV receiver is like one big audio-visualhead manager, and needs to be good at every function. Power power power!!!For many people, all they consider is how "powerful" their AV receiver is - i.e. if it has 100 watts per channel it must be twice as good than another with50 watts per channel... not so. Whilst power is important, for an amplifier to produce twice as much sound output it requires 10 times as much power. So a 100watt channel is twice as good as a 10watt channel. To get twice as good asa 50watt channel you would need 500watts. So whilst power is a consideration, it's nowhere near the most important, as most amplifiers are similar when it comes to power of sound.And be very very very careful that when you're looking at the power of your amp it is being measured in RMS and NOT in PMPO. All you need to know in relation to this is that PMPO (Peak Music Power Output) is a marketing angle that cheap audio manufactorers invented. The term PMPO has never been defined in any industry standard, but there is one consistency with it: it's always misleading. Only refer to the RMS - the continuous power your amp is capable of putting out.So what is more important than the amount of sound my AV receiver can pump out?Easy: the quality of that sound! This is where you need to look at the specs of Distortion and Signal-to-Noise Ratio. The lower the distortion on your amp is the better the sound is. You may havea 150wpc output, but a distortion of 0.5% you're far worse off than 100wpc output and a distortion of 0.01%. Distortion is measured in THD (Total Harmonic Distortion) and will alway be a very small number. The general rule here is: the smaller the better. Compare the THD on various similar items and see what each product offers. Personally, I wouldn't be an amplifier wih a THD of more than 0.1%, and ideally would want lower than that - but that all depends on your budget.Signal-to-Noise Ratio is the ratio of sound to background noise. This is the opposite of THD: the higher your SNR is the better. SNR in modern amplifiers is generally pretty good, and usually meets expectations even in ordinary amps, but remember that a SNR level of 75db is much more desirable than one with 50db.So Which One Do I Buy?..That all depends on your budget. Just remember to take into account all of the specifications, and be particularly wary of any brand you've never heard of. SpeakersMuch of the buying advice for Amplifiers applies to speakers as well.Once again, check all of the specs for your speaker before you buy. Make sure that the power output of each speaker (remember: RMS not PMPO!!!) corresponds with the capabilities of your Amplifier, otherwise you could be wasting your money.Most speakers on Ebay are decent quality, but again, if you're looking for the best of the best, always go with brands you know.Also remember to buy the amount of speakers that correspond with your amplifier: if you have a 5.1ch amp, you will want five speakers and a sub-woofer. If you buy a 7.1ch amp, you will want seven speakers and a sub-woofer. Simple as that.One final thing to consider when buying speakers: the number of drivers on each speaker. A towe speaker (the big standing ones) will generally have at least 1 bass driver, 1 midrange driver and 1 tweeter - but will usually have more of one or the other. A bass driver gives you the low sounds, midrange gives you the middle sounds and a tweeter gives you high sounds. If your prospective speaker only has midrange and tweeters (some do...) then you're missing out on a whole range of sound! Note though that the other speakers in your set will not always have all three types, and this is okay - so as long as your main speakers are capable of giving you what you want!The Full MontyIt goes without saying, but I'll say it anyway: when you're buying a fullhi-fi package just look at the specs of each item individually.Good luck!Well, I hope you get a good buy - as I said, there are many good deals available on ebay. So good luck and happy bidding!!!