Distortion in 3 inch speakers with TDA 2822 amp

Discussion in 'The Projects Forum' started by Vaibhav Shinde, Jan 13, 2014.

  1. Vaibhav Shinde

    Thread Starter New Member

    Jan 4, 2014
    8
    0
    Dear All,
    I have built up a small project of stereo amplifier using TDA 2822M. I am using regulated 5v power supply. And speaker has 4 Ω 10w configuration. I give input to circuit through mobile. Now, when I run circuit at low volumes it runs clean and fantastic. But as I increase volume through 47k POT from mid to high, my speakers starts distorting . And I cant get clear sound. Also bass is not that much good in speaker (Though it has rubber cone ring , just like sub woofer) . When bass effect comes in music, speaker volume goes down... please provide me solution. I want to build custom good bass speaker system for my laptop.Even I used some large 4ohm 10w speakers. But they are also showing same distortion at high volume.
    Please find circuit & speakers used by me in attachment.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,421
    3,357
    Try increasing C1 to 1000 - 4700μF.
     
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  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,741
    759
    USB 5V cannot supply enough power to produce the sound you are looking for.
    Max power is 2.5W at 100% amp efficiency.
     
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  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,773
    1,103
    You can't expect much bass from that circuit. The frequency response drops -3db at ~400Hz. You could try increasing C7 and C9.
     
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  5. crutschow

    Expert

    Mar 14, 2008
    12,991
    3,226
    According the the data sheet, in the stereo configuration the maximum power with a 5V supply into a 4Ω load is about 0.55W at 10% distortion. That's only enough to give a low volume level and little bass, so it's not surprising you are getting high distortion at higher volume levels.

    You could wire the amp as a single-channel with a bridge output connection to increase the maximum output power to about 1W, but that's still pretty low.

    The most you can get with a larger amp at 5V would be about 3W such as one of these.
     
  6. BobTPH

    Active Member

    Jun 5, 2013
    782
    114
    You also need an enclosure for the speaker to get any bass.

    Bob
     
  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
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    And you also need a speaker which can produce bass (low frequency) sound which a 3" speaker can not do.
     
  8. crutschow

    Expert

    Mar 14, 2008
    12,991
    3,226
    Well, they don't do go down to much below 60Hz but it is possible to get some bass from a 3" speaker if you drive it with enough power. :rolleyes:
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    I agree, Crutschow's link to a stereo 3W class-D digital amp module would be a good solution. It will produce a lot of sound from a +5v USB supply, and with pretty good sound quality.

    I used one in a recent project here;
    http://forum.allaboutcircuits.com/showthread.php?t=92589
    which was also running from a +5v regulated supply and driving stereo 4 ohm speakers.
     
  10. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    That's my point. That ain't bass. 60 Hz is just transformer hum.

    The spec on the Tang thing says 65 Hz is the free air resonance of the speaker.

    Thiele-Small Parameters

    • Resonant Frequency (Fs)65 Hz


    In an enclosure, the lower 3dB cutoff is significantly higher than the Fs frequency.
     
    Last edited: Jan 14, 2014
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