Speakers are the most important part of any sound system. While the rest of the system deals with the sound as electrical signals, it is the speakers that turn those electrical signals into sound waves that our ears can hear. As such, the quality of the speakers has a lot to do with how good the system sounds. If the world's best sound system is run through cheap speakers, it sounds like garbage. On the other hand, an inexpensive system that is run through quality speakers sounds wonderful.
Many people use standmounted speakers in their homes as well. Almost any speaker system can be standmounted. There are a few exceptions, such as speakers too large to go on a stand, tower speaker designs, or public address system speakers, which are designed to be hung on a wall. Many speakers, especially those used for professional audio, are built for standmounting. However, even speakers that are not designed for standmounting can be adapted for use with stands.
Many people are nervous about buying used speakers, concerned about receiving damaged speakers. This is a valid concern. However, buying used speakers provides an opportunity to save a considerable amount of money when buying quality speakers for a home audio system. Before looking at speakers, it is helpful for a buyer to understand how they are designed and what the differences between different types of speakers are. This information is applicable to both new and used speakers. Buyers on the lookout for used standmount speakers need to consider their various features, such as construction, bass ports, and power capacity, to make a wise purchase.
Speaker System Design
Speakers that are mounted in a box are more correctly referred to as "speaker systems." The box, or cabinet, is an important part of the speaker as it helps in the creation of the sound. The type and weight of the material used affects the tonal quality, volume, and frequency response of the speaker system.
Most speaker systems for home audio are designed for use in stereo or two channel systems. That is because music is normally recorded in stereo, rather than the more complex 5.1 or 7.1 surround sound used for the cinema. The same principles apply to any speaker system, whether using two or eight. The only difference with these larger systems is having more speaker cabinets placed around the listener so that sound can be more directional.
One, Two, and Three Speaker Systems
Speaker systems can have anywhere from one to eight individual speakers mounted in them although two or three are the most popular. In speaker systems which have more than three speakers, the extra speakers double up on functions. Speaker systems are typically designed to produce a frequency range of 20Hz to 20,000Hz. 5.1 surround sound systems have subwoofers that can go lower than 20 Hz. The purpose of these subwoofers is to make the listener "feel" the music rather than just hear it.
Although there are speakers called "full-range" speakers, that is somewhat of a misnomer. To be full-range, a speaker would have to be able to reproduce the full spectrum of tones, from 20 to 20,000 Hz. While many speakers can in fact do this, the problem comes when they are trying to produce multiple frequencies at the same time. The more frequencies and the broader the range between them, the more difficulty a speaker has in producing them concurrently. Generally, there is somewhat of a compromise, with the extremes of the frequency range dropping off in volume.
Woofers and Tweeters
This is why most speaker systems have two or three speakers of different sizes mounted in them. The larger speakers produce lower frequency sounds and are called "woofers", while the smaller speakers produce higher frequency sounds and are called "tweeters".
Some speaker systems add a third "mid-range" speaker so that the frequency spectrum can be divided between three speakers instead of two. This provides the opportunity for the speaker system to more faithfully reproduce the sound, as each individual speaker in the system is responsible for a smaller frequency of sound.
Speaker Cabinet Construction
As mentioned earlier, the construction of the speaker cabinet affects the tonal quality of the speaker system. It does this in two ways. First of all, most speaker systems are sealed, meaning that air does not pass into or out of the cabinet. The cabinet is sized so that the air pressure inside of it acts as a spring, pushing the speaker cone back out after the magnet draws it in. This helps to create a crisp sound, which more accurately reproduces the original recording.
The second thing that the speaker cabinet does is reverberate. This means that it vibrates with the speaker sound, helping to produce the sound wave. Specifically, this reverberation helps with the creation of low frequency sounds. For this to work properly, the speaker cabinet needs to be made of wood or OSB, an engineered wood product. Cabinets that are made of other materials do not reverberate like wood does. Aluminium cabinets, which are used for some high quality bookshelf speakers, do not reverberate at all, and plastic, which is used for low cost speaker cabinets, does not reverberate properly, producing a "tinny" sound.
In the 1960s manufacturers started building speakers with "bass ports" in them. A bass port is a hole in the cabinet, through which sound from the back side of the speaker cone can come out. The frequencies of sound that are most likely to find its way out of the bass port are low frequencies. This invention of the bass port coincided with the beginning of rock music, which depends heavily on the bass beat and hence, the need for the bass port.
A "tuned bass port" is different than other bass ports in the way that it is designed. Sound travels at a fixed speed in normal air density, so engineers are able to calculate the diameter and depth of a port to match a particular frequency. Since each frequency needs its own depth, these speaker systems are created to provide the maximum possible volume level for specific bass tones. The difference in bass port tuning affects the type of sound reproduced by the speaker system:
Bass Port Frequency
Effect on Overall Sound
Most common bass port tuning; compromise position between the two frequencies mentioned below
Provides the best sound clarity of the various possible tunings; lowest notes receive the most amplification
Provides the most overall amplification of bass sound; however, it creates the most unclear or "muddiest" sound
One problem with bass ports is that the very thing that makes them work also reduces the quality of sound that they produce. A bass port allows the sound from the back side of the speaker cone to come out of the cabinet, effectively doubling the amount of bass sound the speaker system produces. However, this sound is out of phase with the sound that is coming off the front side of the speaker cone. Therefore, the sound is somewhat distorted, normally described as being "muddy".
Most people who buy speakers with bass ports are more interested in the bass boost that they provide than they are in accurate reproduction of sound. For these people, buying speakers with a bass port provides an advantage. However, for others, such as those who are listening to classical music, the bass port reduces the sound quality.
Speaker Power Capacity
Speakers are rated by the maximum continuous power that they can receive without sustaining damage. This is measured in watts of power. An easy mistake to make is to buy speakers that are not rated for as much wattage as the amplifier is capable of producing. As long as the volume level on the amplifier is kept low, this is not a problem. However, when the volume level is turned up past the rating of the speakers, they can become damaged. For this reason it is always a good idea to buy speakers that are of at least as high a wattage rating as the amplifier. There is no problem with having speakers that have a higher power rating than the amplifier.
The most common way that speakers are damaged is damage to the coil, which is attached to the back side of the cone. This coil is a stiff paper tube the diameter of the central dome in the speaker. It has very fine wire wrapped around it, which functions like an electromagnet when the electrical sound wave passes through it. The coil sits inside the magnet, causing the coil's magnetic field and the speaker magnet's magnetic field to oppose one another. This moves the coil, which in turn moves the speaker cone, producing sound. If too many watts of power are put through the coil, it moves too far, hitting the back of the speaker magnet.
As already mentioned, almost any speaker can be standmounted. There are two basic types of stands. The more common style is what is used for professional audio. This is a tripod stand with a single central pole for the speaker to attach to. The advantage of these speaker stands is that they are collapsible for easy movement. These stands require a socket mounted into or onto the bottom of the speaker cabinet for the central pole to set into.
Many speaker systems already have this socket built into the bottom centre of the speaker cabinet. If a speaker system does not have this socket, one can be added. There are both flush mounted sockets and surface mounted ones. The surface mounted ones bolt onto the outside of the box without any more holes than those required for the screws. Once installed, the speaker systems can only be used on stands, as they can no longer sit on the floor. The flush mounted ones allow the speaker to sit on the floor after installation but require a hole be cut into the bottom of the cabinet.
When installing flush mounted speaker stand sockets, the lower speaker in the cabinet should be removed. There is a high risk of damaging this speaker while cutting the hole for the socket. The hole is most easily cut with a hole saw that is slightly larger than the diameter of the socket. There is also another type of speaker stand, and it does not require any sort of socket for the central pole. These are of a contemporary style, manufactured of either wood or metal. The stand provides a platform at the top for the speaker to sit on. This type of stand looks something like a contemporary plant stand.
Checking a Speaker for Damage
When buying used speakers, it is always a good idea to check them for damage upon arrival. As already stated, the most likely form of damage comes from putting too much power through the speaker system and "overdriving" it. This produces an effect in the speaker that is easy to detect. To check for overdriving, remove the speaker grille to expose the speaker cone. Use one hand with fingers spread out to gently press the speaker cone in and out. Pressure should not be applied to the dome in the centre of the speaker but rather all around the speaker with the fingertips. Listen carefully to the speaker as this is being done. If a rubbing sound is heard, the speaker has been overdriven. If no sound is heard, the speaker has not received this type of damage.
Check the Sound
The second thing to check is to ensure that sound is coming out of each of the speakers in the speaker system. This can be done by connecting the speaker and listening to it. If unsure whether one of the speakers is working or not, the easiest way to tell is to lightly touch the speaker cone. If no vibration is felt, then the speaker is not working.
If a speaker is suspected of not working, it can be checked with a multimeter. Speakers are four or eight ohms although those used in speaker systems are usually eight ohms. Disconnect the wires connected to the speaker and connect a multimeter across the terminals to read it. A speaker that is blown measures infinite ohms across the terminals, while one that is good measures either four or eight ohms. Usually, the impedance of the speaker, which is how many ohms of resistance it has, is normally marked on the back of the magnet housing.
Buying Used Standmount Speakers on eBay
There is quite a variety of standmount speakers on the market, from different manufacturers. Many current and vintage models can be found on eBay. To find speakers for home audio, simply type the word "speakers" into the search bar at the top of all eBay pages. To be more specific, you could type "standmount speakers". Once the listing appears, use the category filters to eliminate unwanted speaker types and narrow the selection to "used standmount speakers".
When buying used speakers on eBay, it is a good idea to ask the seller for more pictures to be able to carefully inspect the speaker from all angles. Be sure that the seller can guarantee that they will not be dead on arrival. By eBay's definition, used equipment must be working. Also, be sure to carefully read through the product description and ask the seller any questions you have and ensure they have a return policy in case the speakers do not work or are damaged.
While it is reasonable to take some precautions when buying used standmount speakers, there is no reason to avoid them just because they are used. While used speakers may have some scratches on the cabinets, they should function just as good as new ones. When selecting used standmount speakers, it is important to verify that they match the home audio system they are to be connected to. Specifically, this means verifying that they are designed to accept as much power as the amplifier is putting out. Otherwise, there is a risk of damaging the speaker or even totally destroying it by putting too much power through it.
It is easy to check used speakers to verify that they are good. Before connecting them to an amplifier, gently move the speaker cones in and out by hand, listening for any rubbing noise. A rubbing sound would indicate that the speakers had been overdriven and are damaged. If there is no rubbing sound and the speaker produces sound when connected to the amplifier, it is a good speaker, regardless of its age. Thanks to eBay's extensive listing, finding used standmount speakers is quick and simple.