Speaker selector switches are the most common item bought from Amazon through this website (with over 1000 units sold). Therefore I thought it is high time to look a little deeper at the different speaker selectors and the features available. I also present a table (or 3) outlining the models, features, price and popularity of what readers have bought.
The main reason speaker selectors are used is to distribute sound to multiple speakers while protecting the amplifier from too much load (due to too many speakers).
Please note, speaker selector switches are designed for multi-room installs in a home or small low power installs (like an office or cafe). They are generally suited for low power (under 100 watts) amplifiers. They should be not be considered in a commercial install or for use with high output power amplifiers.
For a more detailed explanation of the issues regarding speaker load and impedance, see my article on connecting multiple speakers to your HiFi. For an explanation on using the various type of speaker selectors and how to wire them, see my article on wiring 4 speakers.
For a good overview on speaker impedance and how speaker selector switches help overcome the issues, watch the video (particularly the 2nd half) in Understanding Speaker Impedance.
Protecting the Amplifier with a Speaker Selector
There are two main technologies employed by a speaker selector to protect the amplifier from overloading due to a low load impedance:
- Series Resistor: this is used on lower cost speaker selector switches. It normally means there is a resistor (4-6 ohms) wired in series with the speakers. This gives the total circuit a minimum resistance which will protect the amplifier. However, this resistor gets hot at higher volume levels. That is why most speaker selectors using a series resistor for impedance “matching” have air vents in the chassis. Obviously there is some energy lost in these resistors as they produce the heat. Most speaker selector switches employing a series resistor have a “protection” or “impedance protection” switch. This switches the series resistor in and out of the circuit. When you are using more than one set of speakers at the same time, the “protection” switch should be activated. When only one set of speakers are being used, or you are using impedance matching volume controls, the series resistor can be switched out to allow “direct connection” with no losses.
- Impedance Matching Transformer: this is used on higher power and higher cost speaker selector switches. An impedance matching transformer inside the speaker selector multiples the impedance of each speaker which effectively keeps the total impedance around the same as any of the individual speakers (providing the speakers are the same impedance as each other). For example: a 4 zone speaker selector with an impedance matching transformer would multiple each of the 8 ohm speakers by four (making them appear as 32 ohms), and 4 lots of 32 ohm speakers in parallel makes a total impedance of 8 ohms. As one of the speaker selector promo says, they “maintain a safe operating load at the amplifier while distributing maximum power throughout your system“. There normally is not by-pass switch on a speaker selector with impedance matching transformers.
A few speaker selector switches connect the speakers in various series and parallel combinations to limit the overall impedance. These should only be used with 8 ohm speakers.
Some very budget speaker selector switches have no impedance protection what-so-ever. They are just a switch turning each speaker on or off. These are not recommended.
For a better understanding of how the different types of speaker selector switches work, see my Speaker Selector Switch Simulators. These show how each type helps with impedance, as well as how they distribute power to each speaker.
The Ins and Outs of a Speaker Selector
A speaker selector is normally known by how pairs (left and right) of speakers can be connected to it. Each pair of speakers is normally in a different room, or zone. Hence, a speaker selector might be a 4 zone, or a 6 zone speaker switch. Sometimes they are also referred to as 4 way or 6 way. This means they are capable of connecting 4 pairs or 6 pairs of speakers respectively. Be aware some manufacturers also confusingly use the word “channels” for the number of output pairs their speaker switch can connect to.
Some speaker selector switches connect to one stereo amplifier, allowing the speaker selector to connect the one amplifier to each speaker connected to it. This allows the same program (music etc) to be heard in every zone or room.
Other speaker selectors allow two different amplifiers to be connected to them. Then for each zone, you can select amplifier A or amplifier B. These speaker switches are marketed as having A/B inputs. Using two amplifiers with different programs allows each zone to select between the two programs available.
Other features often promoted for a speaker selector are:
Volume Controls: These allow the volume of each zone to be separately controlled at the unit.
Power Handling: This states the maximum power (RMS) per channel of the amplifier that should be used with the selector.
Labels: Some manufactures supply pre-printed labels that make your installation look professional.
Speaker Selector Types
There are 4 basic types of speaker selector switches sold by Amazon through this website:
- Simple Speaker Selector Switches: these simply switch between 2 or more sets of speakers (60% of units sold)
- Speaker Selector Switch with volume control: As well as switching between 2 or more zones, they have separate volume control for each zone (20% of units sold)
- Speaker Selector Switch with A/B amplifier input selection (0.5% of units sold).
- Speaker Selector Switch with volume controls and A/B selection (20% of units sold).
How Many Zones?
Speaker selector switches are also categorized by how many zones (or channels of speakers) they can switch. Readers of this website who have purchased speaker selectors from Amazon have mostly bought 4 zone selectors, but other configurations are also useful:
- 2 way selectors are useful when the speakers are only 4 ohms, as two sets of 4 ohm speakers is too much load for most amplifiers (13% of units sold).
- 4 way selectors are the most popular. These can be used for 2, 3 or 4 zones (66% of units sold).
- 5 way, 6 way, 8 way or 10 way speaker selector switches can be used to wire many speakers. With this many speakers, impedance protection is very important (21% of units sold).
The following tables list the speaker selector switches bought from Amazon through this website. I’ve added as much helpful information as possible including:
- the supplier/seller
- the model number and/or description of the product
- the maximum RMS power (watts) the unit can handle from each channel of the amplifier(s) connected to the selector switch.
- the average price of each product bought from Amazon
- the percentage of sales of each item in its class (2, 4 or 5+ zones) through this website
- a description of the impedance protection method used, warnings and features
- a link to download the manual, if I’ve been able to locate one
- a link to each item on Amazon – click on each picture to go to that item on Amazon for further information. Disclosure: If you buy through the Amazon links Geoff receives a small commission from each sale.
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