So you have a set of wired speakers you want to make Bluetooth compatible? It can be a pretty straightforward project that will save you on a set of comparable Bluetooth speakers.
Here are the steps to add Bluetooth functionality to a normal speaker:
There are a number of reasons you might want to hook up your speakers for Bluetooth. Enabling Bluetooth allows you to stream audio from any Bluetooth capable device. This means you can watch videos on your laptop with your speaker, or you can play DJ on your phone.
To make your speakers Bluetooth capable, you will need a Bluetooth receiver. A Bluetooth receiver takes a wireless Bluetooth audio signal and converts it to a line-level electrical audio signal. A line-level signal is a low voltage signal that is resistant to noise. This is the same signal you will get out of a preamp, laptop, or cellphone.
Apart from headphone speakers, a line-level signal is not sufficient to drive a speaker. Line level signals are designed to transport a sound signal using a minimal amount of power. A line-level signal is meant to be boosted before passing through your speakers.
Bluetooth receivers are generally fairly inexpensive. In general, you can get a good quality Bluetooth receiver for $10-30. Generally speaking, a Bluetooth receiver will have a female aux jack and female RCA connections. You can also find Bluetooth receivers, usually designed for car audio systems, that will only have a male aux output.
Depending on your speakers and the Bluetooth receiver you get, you will need to get (or make) certain cables to hook them together. Sometimes, these cables will be easy to find. However certain set-ups will require you to improvise.
For the most part, a Bluetooth receiver will have female stereo aux and RCA outputs. If you chose to get a car adapter, however, it will come with a male stereo aux output. In general, the aux outputs are intended for computer speakers whereas the RCA outputs are intended for home audio speakers.
Powered speakers have their own external power supply. Powered speakers use this power supply to add voltage and current to the line-level signal. Because of this, you can plug a Bluetooth receiver directly into a set of powered speakers.
Alternatively, if you want to add a Bluetooth audio channel to your powered speaker system, you will want to hook your speakers up to a preamp’s output channel, and plug the Bluetooth into one of the audio input channels of the preamp and use the other channels for your other audio devices.
A preamp is also a good way to add volume control to powered speakers that don’t have one. If your powered speakers do not have their own volume control, it is highly recommended that you get a preamp. Otherwise, your Bluetooth device will be the volume control, and you will need to remember to set it to the appropriate volume before you listen every time.
Passive speakers do not have their own power supply. With passive speakers, you need to amplify the line level signal with an amplifier or A/V receiver. If you are using a power amplifier, you can hook the Bluetooth receiver directly into any open audio input channel.
If you have an A/V receiver, ideally, you should hook the Bluetooth receiver into the HT Bypass or Direct In channel. The HT Bypass or Direct In channel skips the preamp stage so that your A/V receiver doesn’t control the volume, gain, or EQ settings. This is because the Bluetooth device effectively acts as a preamp.
If your A/V receiver doesn’t have an HT Bypass or Direct In, you can still hook it up to an empty audio channel. This will likely make the audio very low when your Bluetooth device is at a normal volume. Use the Bluetooth device to control the volume so that you don’t disrupt the volume settings for your other devices.
Where you may run into trouble is with the speakers themselves. Speakers generally come with one of three kinds of connections. The easiest to hook up to a Bluetooth device with be RCA, since most Bluetooth receivers have RCA outputs and therefore only require standard RCA cables to plug in.
If you are using a car audio Bluetooth receiver, you will need to get a converter cable. You will need to find a cable with a female aux connection on one side. If you have speakers with an RCA connection, finding an aux female to left and right male RCA cables is usually not too difficult. However, if your speaker has speaker clips or uses banana plugs, it may be more complicated.
A final speaker connection you may encounter is a banana plug. Like with speaker clips, banana plugs have designated positive and negative plugs. Whereas most connections combine positive and negative connections into one plug, banana plugs have separate plugs for positive and negative. Thus, if you find an RCA to banana plug connection, it will have one RCA plug per every two banana plugs.
Another kind of connection you might run into is speaker clips. Rather than a standard plug, speaker clips have spring-loaded terminals that accept bare wire. Just like banana plugs, speaker clips have separate positive and negative terminals.
Although you can find RCA to speaker wire cables, they are not very difficult to make yourself. Simply take a standard RCA cable and cut off the plug on one side. Strip off a small amount of the outer tubing to expose the two wires inside. Strip a small amount of tubing off of each wire and plug one into the positive terminal and one into the negative terminal.
Ideally, these internal wires will be color-coded in accordance with the speaker clips. However, if they are unlabelled, it should not make too much of a difference, since audio signals are alternating current.
The most complicated conversion you may need to make is between a stereo aux connection and speaker clips. Whereas RCA connections are single-channel, having only one positive and one negative wire per plug, stereo aux connections combine two channels in a single plug.
The positive signals in a stereo aux connection are grounded by a single negative signal. Thus, if you strip a stereo aux cable, you will find three wires inside: left, right, and ground. Usually, these will be labeled red for right, white for left, and the ground wire will either be black or may be unwrapped.
Since the left and right channels of a stereo aux cable share a ground, you will need to split the ground. Get two lengths of small gauge wire and attach them to the ground wire and solder the three wires at a single point. Hook up the left channel to the positive terminal on one speaker and the right channel to the positive speaker of the other speaker. Then hook up one of each of the ground extensions to the negative terminal of each speaker.
Once you have connected your Bluetooth receiver to your speakers, you have finished the hard part. Now you will need to pair your device with the Bluetooth receiver. First, turn on your Bluetooth receiver. If you have powered speakers, plug them in after turning on your Bluetooth receiver.
Next, set your Bluetooth receiver to pair. Finally, turn Bluetooth on on your device and find your Bluetooth receiver and pair. At this point, you should be able to broadcast audio to your speakers. Happy listening!