Thanks to weeks of research on this site, I built a BoomBox out of one of these TDA7492 amp. Always wanted something nice to take camping and to the beach.
Short Version: How much sound quality (if any) am I leaving on the table powering it from only 12v, instead of 18v?
Long Version:
Using mostly spare parts from around the house, I pieced together one of those Suitcase Boom Boxes. .
- 12v SLA 8aH battery
- pair of 4-ohm Kicker 6.75" 2-way coax speakers.
- XR1075 BBE tone/volume control Circuit Board
I'm really really pleased with the outcome. Even somewhat surprised at how nice it sounds. The audio input signals are wired/tied together in mono, and the speaker outputs are left wired in stereo (separate L and R)
I see some posts where people add a 18v or 24v DC->DC Boost converter to up their 12v source to a higher voltage. I realize the amp can easily handle the higher voltage, and might even prefer it.. but... would I benefit from doing the same? Would adding a 12v->18v boost converter to my 12v SLA power source make a noticeable improvement in sound quality? Already the power/volume seems quite good, so I'm not sure I'm worried about volume, but I'd really like to maximize quality. Of course, being a battery -powered setup, battery life is important too, but adding another 12v SLA would not be hard if I needed to.
Thanks
Shane.
Short Version: How much sound quality (if any) am I leaving on the table powering it from only 12v, instead of 18v?
Long Version:
Using mostly spare parts from around the house, I pieced together one of those Suitcase Boom Boxes. .
- 12v SLA 8aH battery
- pair of 4-ohm Kicker 6.75" 2-way coax speakers.
- XR1075 BBE tone/volume control Circuit Board
I'm really really pleased with the outcome. Even somewhat surprised at how nice it sounds. The audio input signals are wired/tied together in mono, and the speaker outputs are left wired in stereo (separate L and R)
I see some posts where people add a 18v or 24v DC->DC Boost converter to up their 12v source to a higher voltage. I realize the amp can easily handle the higher voltage, and might even prefer it.. but... would I benefit from doing the same? Would adding a 12v->18v boost converter to my 12v SLA power source make a noticeable improvement in sound quality? Already the power/volume seems quite good, so I'm not sure I'm worried about volume, but I'd really like to maximize quality. Of course, being a battery -powered setup, battery life is important too, but adding another 12v SLA would not be hard if I needed to.
Thanks
Shane.
It will play louder and with more punch on bass with higher voltage. At sustained high volumes though, you have to check if your current draw is sufficient, otherwise the transients will be better at higher voltage. I prefer 19v laptop smps to 12v smps for my class D amps. 18v is similar to 19v so there will be an audible improvement.
Check out the TDA7498 ($11 on Aliexpress), it can handle up to 32v - but 24v sounds more improved than 19v. Great amp.
Check out the TDA7498 ($11 on Aliexpress), it can handle up to 32v - but 24v sounds more improved than 19v. Great amp.
With the same input amplitude at the same fixed gain, they will sound exactly the same at 12V or 18V for the case that your output-amplitude is hitting the supply rails.
Higher voltages gives you higher undistorted output with higher input amplitude.
Higher voltages gives you higher undistorted output with higher input amplitude.
Thanks guys.. that's kinda what I was expecting. If I understand right, the 12v is really only a limitation at higher volumes. At low to mid volumes, I should not notice any difference in sound quality.
Depends on the speakers SPL and impedance. With 90dB/W, a speaker is twice as loud as an 80dB/W one at the same input power. Beside this, 4R speakers gives you more output than an 8R one at low voltages. (+3dB)
Nope. +10dB is twice as loud. +3dB is twice the power.
For being twice as loud out needs 10x times power.
For being twice as loud out needs 10x times power.
Ok sound loudness perception by the human ear. The 10dB is an approximate rule of thumb. This is a psychoacoustic based value and we should stick with with SPL.
Last edited:
"sound loudness perception by the human ear" is what i need outside. 🙂
Last weekend we had a ride by bike with a "small" sound-system, 122dB SPLmax is not enough.. 😵
Last weekend we had a ride by bike with a "small" sound-system, 122dB SPLmax is not enough.. 😵
- Status
- Not open for further replies.