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I use my Seeeduino V4, DFPlayer mini, and this speaker module from AliExpress to create an automatic doorbell. The problem is that it seems that this speaker module's Yurobot amplifier is not powerful enough to create a noise-free loud sound. Also, the bundled speaker is 0.5 W, 8 Ω.

There is a volume selector on the speaker module. If it is selected to a value a bit higher than 0 then the sound's quality is quite high (click here to listen), but the volume is not enough by far for a doorbell, even though the DFPlayer's programmed volume is set to maximum.

But if I increase the amplifier's volume selector to something near maximum, I start hearing some very scary noises (please click here to listen).

How can I increase the volume without having hard-to-listen-to noises? Maybe I need to buy another, better amplifier?

ocrdu
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Starter
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3 Answers3

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The DFPlayer already has a 3 W amplifier on it, so you can connect a speaker directly to the DFPlayer. There is no need for an extra amplifier.

If you do connect an extra amplifier to the DPlayer, and turn the volume of the DFPlayer up too far, the input of the second amplifier will clip and it won't sound good.

Also, the output of the DFPlayer is probably from a class-D amplifier designed to be connected directly to a speaker; it won't play nice with other amplifiers.

You should try how the DFPlayer sounds when you connect a speaker directly to it. The 0.5 W speaker you have is not a good fit; it can't handle the power of the DFPlayer's amplifier.

A 3 W (or more), 8 Ω speaker would be good for this if you want to use the maximum power the DFPlayer can deliver. According to most publications on the interwebs a 2 W, 8 Ω speaker will also do, but I would be careful with turning the volume all the way up.

Note that the DFPlayer can pull a fair bit of current (about 25 mA in standby, and in the order of 200 mA when playing) and it needs a power supply that can deliver that.

ocrdu
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Interesting! The wattage rating of the speaker does not affect its loudness, the efficiency does at a given wattage. Wattage is the maximum amount of power you can drive the speaker with, that does not indicate the source can provide more or less. The SPL (SPL stands for sound pressure level and is also commonly referred to as efficiency and sensitivity. This parameter represents how loud a speaker is. A higher SPL equates to a louder speaker). To get more volume out of a speaker you have to put more power in. Ohm's Law explained this. The impedance (AC Resistance) of the speaker varies with frequency but typically a nominal number such as 8 ohms is used. Looking at Ohm's law the only way to get more power is to lower the impedance or increase the voltage with voltage being the most popular as well as the easiest. Putting more power into a speaker then it is rated at will eventually destroy it as well as distort the sound. This may not be noticeable to the human ear at low amounts but it is there. Also the sound coming out is directly related to the signal going in. Clipping is a common occurrence when the amplifier is being over driven ie. it is asked to put out a higher voltage then it is capable of. There is an old saying garbage in garbage out. That includes the components as well. To solve your problem you probably need an amplifier capable of doing what you want and a speaker that will at a minimum handel the worse case power you will send it.

Gil
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i was experiencing the same phenomen in my project , and got to this page in my research . I am using a tda 2003 amplifier and the speaker is a intercom that i modify so changing the speaker is out of question also the amplifier is a good and versatile . The problem is in the gain setting of the amplifier . I was using a 220ohm resistance on the gain setting . going back an forth i was getting better sound with low gains. i hooked up a potetiometer in the place of the resistance to fine tune the gain aand at 8 ohms i get the sound that i want.

paulyvon97
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