If you are looking to control your audio with arduino, here’s it is. It uses TDA7419 chip which has a lot of features for controlling your audio. It has 4 input selector, bass control, mid control, treble control, loudness control and a built-in 7 band spectrum analyzer.Continue reading “Arduino controlled bass mid treble and input selector with tda7419”
Build this simple 2 band tone control Circuit using transistor with complete schematic and layout you can download.Continue reading “Simple but effective 2 Band Tone Control Circuit using transistor”
A good way to protect your speaker from overloading is by using a limiter circuit. This circuit protects your speaker by limiting the input signal to the amplifier by a certain level.
This circuit uses an IC from New Japan Radio Inc. It is NJM2761 which is specially designed for limiting audio signals. It is designed for powered speaker system to protect the speaker from overloading.Continue reading “Audio Limiter Circuit”
Here’s a 3 band tone control with subwoofer output circuit. Take note that the main output are full range. This is not a 2.1 crossover circuit. It is powered with single power supply so you can use a battery or a simple ac/dc power supply.
Here’s a simple circuit you can build for your own low power home audio project. It only uses a NPN transistor rather than the most conventional OPAMP versions. It is simple and easy to build using an universal board. It can be powered by 9v or 12v single power supply.
Here’s a simple circuit you can use to boost more bass from your music. It can be powered by 9V battery or a 12V DC adapter. Take note that this is just basically a 1 band tone control with +- 17dB range at 60Hz bass frequency. You need it to connect before the amplifier input. This can’t be connected directly to speaker. The output of this circuit will be connected to the input of your amplifier and the input of this circuit will be connected to your audio source(i.e. mp3 player).
Here’s a simple electronic stereo audio selector switch that can be used for arduino. You can directly connect the pin 1, 16, 3 and 18 to arduino for selecting the source. This pin can accept as low as 2V for logic high according to its datasheet so no need for level shifter.
If you are looking for a mic preamp with bass and treble control, you may consider this one. I designed it for my future mixer build. I am planning to build one someday when I am not too busy.
ABOUT THE CIRCUIT
The circuit is only on design stage, not yet done any prototype but it is working on my simulation. This is an improved version of the preamp on my audio mixer design I posted.
The rolloff on the 10k-20kHz range is caused by the capacitor C8. This is done to make sure the system will not allow any radio frequency to pass especially AM radio signals. If you want that roll-off to be more aggressive, you can increase it. Treble frequency is set by C3 and C4 while C2 is for setting the bass frequency. Increasing those capacitor values will decrease the frequency. For instance you want the bass to have more boost on the lower end frequency, just increase the value of C2.
Gain is set by R1, if you want more gain, increase R1 value. Potentiometer used are 100k, using 50k or lower will decrease the boost and cut range by around 3dB.
All range: bass and treble at 0%, 50% and 100%
Bass control (0%-100% at 10% increment)
Treble control (0%-100% at 10% increment)
Here’s an improve tone control with 12dB boost on 80Hz for better super bass experience.
About the Circuit
The circuit is made up of 2 opamps TL072. This can be changed to other general purpose opamps like LM358. First stage opamp gain is set to 1, if you need more gain, you will need to decrease R2. If you want to use it for Mic, use 1k for R2.
Take note that there is no capacitor in series with the output, this is only for simulation, in reality you will need to add capacitor at the output to cancel out the DC offset on the output.
Want more Bass?
This circuit can already deliver +12dB boost at 80Hz but if that is not enough for you, you may want to decrease value of R3 and R4 for higher bass boost. Decreasing it to 3.3k will give you a bass boost of around 17dB at 80Hz! That would be too much and take note that you may need more power for that.
Flat response ( bass and treble set to 50%)
there is roll off at both ends but it is only around -1dB which is fine. The roll off on the 20kHz is intended to reduce AM interference. This can be reduced by reducing C7 value. While the roll off at the lower end is needed to reduce subwoofer excessive movement. For music listening, the 20Hz to around 50Hz frequency is not important because almost no instrument is playing on that range of frequency. You can further decrease that roll off at 20Hz by decreasing value of C1.
100% Bass and Treble
0% Bass and 0% Treble Vs Set to both maximum
Please do take note that the simulation part numbering is not the same on the PCB part numbering. In example R1 on the simetrix simulation file is not the same R1 on the PCB file.
For PCB design, I used only single layer PCB so it will be easy to build for anyone. But in order to do this, I needed to add some 0 ohm resistors as jumpers. Just use wires for these 0 ohm resistors, these are R13, R14 and R20 on the schematic.
3D Render from Kicad Software
You can download the kicad project file and simetrix simulation file here:
In case you want to connect your audio mixer or electronic piano or any other line level audio equipments to your computer or laptop for recording, here is a simple USB audio interface circuit that does the job. It is based of PCM29XX IC from TI. This is used in many analog audio mixers with usb interface such as the Behringer Xenyx USB mixer series.
About USB audio interface circuit
This circuit is USB powered. The IC has 16bit delta sigma ADC and DAC and capable of up to 48kHz sampling rate. it has stereo line level input and outputs.The crystal needed is 12MHz.
Quick PCB design
Here is a simple PCB layout that I designed using kicad software.
Want to have a copy of the Kicad design? Just like my facebook page and send me a message. thanks for visiting… 🙂
Since I needed this circuit for my recording may piano and guitar covers, I built my own using universal PCB. This is what I used on my guitar and piano covers on my youtube channel here.
There’s no need for drivers, it installs automatically when you plug it in. It has 16bit ADC/DAC with up to 48kHz sampling which is good enough for recording. 16bit/48kHz might not sound great but it is actually good. This chip is used by Behringer on some of their Xenyx USB mixer and also on their cheap usb audio interface. The audio quality is not the best but it is better than those cheap USB sound card on the market. This is good enough for recording for you youtube content.
Here is the actual video of my prototype in action.
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USB audio interface Parts list
|C1||1u||16V electrolytic capacitor|
|C3||4.7u||16V electrolytic capacitor|
|C4||4.7u||16V electrolytic capacitor|
|C5||1u||16V electrolytic capacitor|
|C6||1u||16V electrolytic capacitor|
|C7||1u||16V electrolytic capacitor|
|C8||1u||16V electrolytic capacitor|
|C9||1u||16V electrolytic capacitor|
|C10||1u||16V electrolytic capacitor|
|C11||4.7u||16V electrolytic capacitor|
|C12||4.7u||16V electrolytic capacitor|
|J2||Input||3pin JST connector|
|J3||output||3pin JST connector|
|R1||2.2 ohms||Resistor SMD or 1/4W or 1/8W|
|R2||1M||Resistor SMD or 1/4W or 1/8W|
|R3||1M||Resistor SMD or 1/4W or 1/8W|
|R4||1.5k||Resistor SMD or 1/4W or 1/8W|
|R5||22 ohms||Resistor SMD or 1/4W or 1/8W|
|R6||22 ohms||Resistor SMD or 1/4W or 1/8W|
|R7||1M||Resistor SMD or 1/4W or 1/8W|
|R8||1M||Resistor SMD or 1/4W or 1/8W|
|R9||1M||Resistor SMD or 1/4W or 1/8W|
|R10||220 ohms||Resistor SMD or 1/4W or 1/8W|
|U1||PCM2902C||USB interface IC|
The parts list does not include input and output connectors, you may opt to use RCA or phone jack connector.
I am planning to build an improve version of this device and sell it online so stay tuned! Subscribe to my youtube channel and facebook page to keep you updated! 🙂