DROK® TDA7850 Car Amplifier Board 4*50W Treble Bass Adjustable DC/AC 12V HIFI 4-

[manmohan August 9, 2016 at 8:21 am Post count: 0]

#6946 Reply |

I brought DROK® TDA7850 Car Amplifier Board 4*50W Treble Bass Adjustable DC/AC 12V HIFI 4-Channel Output from Amazon UK. I used mp3 decoder (LSON MP3 FM Bluetooth decoder with 2.3inch display) board as input. Amp is powered from a 12V 5A transformer. I connected two 4inch car speaker from Focal (to the front speaker output of the apm). At high bass setting there is distortion. Audio output is clipped it seems. Audio output is broken at high bass setting and if the song played has good bass. Powering the MP3 decoder from separate 5v SMPS. Please help in finding the issue. Will powering the decoder from the amp solve the issue?

[DrokKeymaster August 10, 2016 at 2:32 am Post count: 2971]

#6959 Reply |

Dear manmohan，
Thank you for writing in.
Could you please tell us more details of your operation, such as the parameters of the car speakers?
How much are the power of the speakers and the frequency band,high frequency, intermediate frequency, low frequency or full frequency?
This product is for full frequency speaker.
The power and the frequency of the speaker make a great difference in the audio output.
For example, the output power of the amplifier is 4*50W, if you use two 10W speakers, the output power of the amplifier is too high for the speakers to afford, then there will be distortion during the high bass setting.
And please note that all the input audio signal must be low-level signal,i.e.pure signal, not the high-level signal which enlarged by other device.
Hope this can help you.
Best regards

[manmohan August 11, 2016 at 3:45 am Post count: 0]

#6975 Reply |

Let me explain about the input. I am using a LSON 2.3″ LCD Screen Decoders W/ Bluetooth / Radio / MP3 / Recording. Please check in following site “http://www.dx.com/p/lson-2-3-lcd-screen-decoders-w-bluetooth-radio-mp3-recording-1-x-cr2025-297535”. If I connect a headphone directly at the output of this device, the sound is very feeble. One cannot hear anything even at the highest volume. So I believe it is a pure audio source.
Now about the speaker. The speaker is Focal Auditor R100C. 60W. I have a FREQUENCY RESPONSE/IMPEDANCE plot, but I dont know how to attach a file. Please check the link fr technical details “http://www.focal.com/india/index.php?controller=attachment&id_attachment=4138” Please find the technical details that I got below

SPECIFICATIONS
Nominal power:-30W RMS
Maximum power:- 60W
Sensitivity(2,83V/1m):- 88dB
Nom. impedance:- 4 O
DC resistance:- 3.4 O
Flux density:- 0.96T

PARAMETERS
Fs:- 104.1Hz
Vas:- 1.73L
Qts:- 1.021
Qes:- 1.19
Qms:- 7.17
Re:- 3.4 O
Sd:- 55.42cm²
Cas:- 5.62E-08m5/N
Mas:- 189.51Kg/m4
Ras:- 17287.71 O.ac
Cms:- 4.02E-04m/N
Mms:- 5.82g
Rms:- 0.531Kg/s
Ces:- 513.94mF
Les:- 4.55mH
Res:- 21.33 O
BI:- 3.37N/A
SPL:- 84.00dB
f-3dans 30L:- 80Hz

[DrokKeymaster August 11, 2016 at 8:15 am Post count: 2971]

#6980 Reply |

Hello manmohan,
Thank you for your detailed information.
From the parameters of the speakers, the frequency of the speakers is 104.1Hz which means that the peakers are low frequency speakers.
This product is for full frequency speaker.
If you want to apply the this product to your car speaker,each of your car speaker box needs to connect a mid-high frequency speaker in parallel so that the car speaker can become a full-frequency speaker. The power of the a mid-high frequency speaker can be 10-20W.
And it is better that you can add a 10UF capacitance for the isolated coupling between the low-frequency speaker and the mid-high frequency speaker when they are connected in parallel
Or you can also just add a frequency divider so that you can connect any speakers with different frequency.
Hope this can help you.
Best regards

[Author]

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