Buying the Right Speakers on eBay

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Buying the Right Speakers on eBay

Buying speakers seems at first glance as if it would be a relatively straightforward proposition. However, a dazzling array of hundreds of different models and types for either home or car speakers will pop up, simply by typing the word 'speakers' into eBay,, so it is advisable to narrow down the search with select, targeted keywords when entering search parameters into the search box. The potential buyer can try the suggested related searches, or, if they are feeling adventurous, try alternative words, such as 'kitchen speakers' or 'bathroom speakers' to bring up models that are humidity-resistant.

By narrowing down the search parameters, what at first may result in a massive, even overwhelming number of possibilities becomes quickly far more manageable. If the search comes back with too few results, considering widening the search parameters.

When considering purchasing a pair of speakers from eBay, the buyer should be aware of just what kind of speakers, and for what kind of sound system, they will be connecting them to, before deciding on the final purchase.

Different Speaker Styles, Impedance and Power Ratings

Broadly speaking, speakers fall into several categories, namely automotive speakers and those used in the home, on a desktop PC or laptop, and those specifically designated for home entertainment systems.

Speaker Type

Impedance (Ohms)

Power Rating (Watts)




Home – General



Kitchen / Bathroom



PC / Laptop



Home Entertainment System




Please note that the above figures are estimates based on averages. If the user is in doubt, they should check with the manufacturer. As the above chart shows, there are significant differences between these five popular types of speaker. Generally speaking, speakers designed for one application are not always suitable for use in another. One good example of this is the required moisture resistance a kitchen or bath speaker should possess, thereby making a standard room speaker inadvisable in those conditions.

Car speakers, in particular, may look attractive as a substitute for living room speakers. A quick glance at their impedance, however, will show that, while in theory they could be connected to a home amplifier, in practise, as soon as the amplifier is turned up, it will quickly overload and most likely overheat, a potential safety risk. Because of the wide variety of car speakers available, it may be worth narrowing down the search, perhaps to include words such as ‘door’, or ‘subwoofer’, depending upon the application or desired feature.

As a general rule of thumb, home amplifiers are designed to run speakers of at least 4 ohms, while car amplifiers, because of the lower supply voltage – generally 12 volts – must run into a lower impedance to generate sufficient power.

Standard room speakers connected to a central sound system are generally rated between 30 to 150 watts, as home amplifiers tend to be similarly rated. It is perfectly okay to run 100-watt speakers from, say, a 30-watt amplifier, but running 30-watt speakers from a 100-watt amplifier will need some care. As volume is increased on an amplifier, speaker sound will generally be distorted. Prolonged use at these high volumes will undoubtedly damage the speakers and possibly the delicate output stages of the amplifier.

Kitchen and bathroom speakers are generally ceiling mounted and waterproof, and generally of much lower power, not normally a problem as they tend to be used at much lower ‘background’ levels than main living room speakers.

PC speakers are generally active. This means they have integral amplifiers in the boxes with the speakers. They can be powered by battery, but more often by a low-power mains adaptor, or even directly from the PC or laptop itself via a USB port. They are usually of much lower quality and power than domestic speakers, but, unless they are being used for extreme gaming, this is not typically a problem. In recent times, PC speakers have appeared on the market and are familiar to most home entertainment system owners. These speakers are advertised as ‘2.1’ or even ‘5.1’. The number before the decimal point refers to the number of main channels, while the number after the point refers to the number of background or bass speakers. Therefore, a ‘2.1’ system would be a stereo set with a single bass subwoofer, while a ‘5.1’ system would be front left, front right, front centre, rear left, rear right, with a single bass subwoofer.

Increasingly, home entertainment systems merge the roles of home vision and home audio in that a home entertainment system will give true cinema-quality sound, yet be able to adequately handle music from such sources as an iPod or iPhone via a docking system.

Multi-way Speakers

Speakers are often advertised as ‘2-way’, or ‘3-way’ and up. This refers to the actual number of drivers in each box. ‘Full-range’ is a single speaker that will handle all frequencies; ‘2-way’ is two speakers, one for handling the bass frequencies and the other for the middle and uppermost frequencies. ‘Three-way’ means one for bass, one for mid-range, and one for higher frequencies. Generally, the higher the number of ‘ways’ a speaker system has, the higher the sound quality.

Active or Passive

Active speakers do not have an impedance rating as they have integral amplifiers, often built right into the speaker boxes. Passive speakers are just that: they have no amplifiers and, hence, need an amplifier to power them.

Frequency Response

Speakers are often marketed and advertised by their frequency response. For a home speaker system, this might be ‘70–18,500 Hz +/- 3 dB’, for example. This means that the speaker’s response will be to within 3 dB (decibels) of ‘flat’ between 70 and 18,500 Hz. Careful attention should be paid to the number that follows the ‘+/-’ sign as, using this example, 3dB is marks the halfway point of the volume, whereas 6 dB would mark a quarter of the volume, as dB measurements are in a logarithmic scale. When looking for a speaker system that will play modern dance music, for example, the potential buyers should always look for the lowest possible frequency at the lower end, with the highest frequency as high as possible. As a rule, the human ear cannot hear much past 20,000 Hz.

Speaker Ratings

The industry standard of power is the ‘RMS’ rating. This stands for ‘Root Mean Square’ and generally means that, if an amplifier has a given output of X watts RMS, then the user can safely connect speakers of the same, or higher, RMS rating.

However, advertisers, in the quest for ever-increasing numbers have devised another rating, that of ‘PMPO’. This stands for ‘Peak Music Power Output’. In theory, this is the peak maximum power a speaker will handle, but, in reality, this is only for a few milliseconds before it overheats, often with disastrous consequences. PMPO is largely meaningless, and the buyer should examine the product specifications closely to see what the actual RMS rating is. If the RMS is not quoted, but PMPO is, then the buyers should divide that PMPO by a factor of between 10 to 100.

As an example, a speaker might have an RMS value of 5 watts or less, while it may be marketed as ‘50 watts (PMPO)’. Turning up the volume on a 50-watt (RMS) amplifier when connected to a pair of 50-watt PMPO (5-watt RMS) speakers would very likely blow both the speakers and the amplifier.

As a quick test, the potential buyer should consider the size of the magnet at the rear of the speaker, particularly on models of car speaker that have no cases. A speaker rated at 100 watts RMS should have a magnet of at least 150 mm diameter, with a magnet thickness of roughly 70 mm. Do not hesitate to contact the seller to ask for verification of the magnet size if it is not evident in the information or photograph(s) in the listing.

Speaker Impedance

As previously stated, living room speakers are generally rated between 4 and 8 ohms, while car speakers have a much lower rating. As a rule, the lower the impedance of a speaker, the more power it will draw from the amplifier when the volume is increased. This generally makes the amplifier run hot. Back in the 1960s and ’70s, certain manufacturers designed amplifiers that would quite happily run speakers at 4 ohms. Connecting a pair of 8-ohm speakers to such an amplifier would not damage it in the slightest, but the user might notice that the sound level is lower, therefore, increasing the volume slightly might be warranted.

How to Buy the Right Speakers on eBay

With so many speakers available for purchase on eBay,, it is not uncommon to feel a bit discouraged or overwhelmed. Pay attention as to whether the speakers you are considering are in fact new and would thereby be accompanied by a desirable twelve-month manufacturer’s warranty, or whether they have been pre-owned and are not protected by any manufacturer’s guarantee. If they are second-hand, carefully look at the photos to note any possible, evident damage.

It is always a good idea to check the seller’s eBay ratings and review the comments that have been posted by previous buyers, and verify whether or not the seller has a satisfactory returns policy. This is because, while a set of speakers may look visually appealing, with no apparent damage, upon initial inspection, if the speakers are used and have been overloaded at some point, you won’t be able to test this until you plug them into your amplifier. It’s best to ensure ahead of time that a seller will accept them back if they prove faulty for your own peace of mind.


With some understanding of speaker terminology and specifications, any buyer will feel a great deal more comfortable when it comes to purchasing speakers online through eBay.. A buyer should not be hesitant to shop around and become familiar with the various features and specifications of the types of speakers desired in order to ensure complete satisfaction with the eventual purchase.

If careful attention is paid to the speaker’s ratings, that is, the total amount of power it will handle, the RMS (not PMPO) rating, the speaker’s impedance, its frequency response and the number of ‘ways’ it is, then the purchaser can be confident of making an informed decision the first time round.

It’s easy to overlook whether the buyer needs active vs. passive speakers. When faced with the line output of a computer or television, then a buyer should choose active speakers. If the user already has a music system with its own amplifiers built in, then the speakers they should consider purchasing are passive speakers..

One final important but often overlooked detail is whether the physical size of the proposed speakers will comfortably fit in in their future home.

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