TDA7492P, questions about crossover, speakers, Li-ion batteries

Thread Starter

Thomas Geslin

Joined Jun 3, 2017
Hello everyone!

This is my first thread here, so let's get straight to the point! I'm building a portable bluetooth amp + speaker for a individual science project and i've been roaming for a few days on the internet but I still have some questions i can't solve on my configuration.

I chose for the amp the TDA-7492P with the following specs:

Power supply: 12V 3A (recommend) ; [9-20V]
Amplifier IC: TDA7492P-Stmielectronics
Sound Source: DCM8633 Bluetooth 4.0 module
Output mode: Stereo
Output power: 25W + 25W; THD=10% ; Vcc=18V; RL = 6ohms
Adaptive speaker: 20W/4ohms, 20W/6ohms, 20W/8ohms

and I have currently 2 speakers "full-range":

Visaton FRS8 -4 (from datasheet):
Impedance: 4 ohms
Rated Power: 30W
Maximum Power: 50W
Frequency Response: 100 - 20 000 Hz

Here are the dimensions of my prototype enclosure, after calculating online from the FRS8 datasheet:
28*10,5*17 cm or (11*4*6,5 in)


1) First, do you see anything weird in the choice of my components or does it seems ok for you? (can my amp drive my speakers correctly?)

2) In the first place, i was considering getting a FRS-8 and this 6 ohm tweeter but in the end, it costs more than the 2 drivers i already got.
Is it really bothering in terms of sound if I mount the 2 full range speakers (one on each channel) and no tweeter? What would you recommend?

3) If yes, what components and values should i look for a passive crossover?

4) I'm looking for a way to make a Li-ion battery to power my amp. Here's what i'm thinking of, any critic?

4x 3000mAh 3,7V Li-Ion (in serie)

5) What charging protection module should I buy?

Looking forward to read you all, thanks a lot!


P.S: any useful contribution will be listed in the "special thanks" in my final report ;)


Joined Jun 22, 2012
For battery power i would go with a 12V sla type, rated at 7Ah it maybe too big for you if you want it portable, if not good and easier to charge up, your speakers will cope ok, looking at crossovers choose ones that give you the range of your speakers,.

Thread Starter

Thomas Geslin

Joined Jun 3, 2017