Choosing amplifier board for Subwoofer

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Hi guys,

I am a DIY enthousiast and i was planning to build a subwoofer from scratch!
I am planning to build a subwoofer starting from a single 8 or 4 Ohm (not sure which one yet) rated around 100W RMS 200W peak driver.

I already own a laptop power supply (19V, 6.3A) and i would like to use this, with or without a step-up/step-down converter.

I was already scrolling through all topics and noticed some trends:
-TPA 3116 boards provide not even 50W RMS mono for 8 ohm speakers, so this will not be sufficient(?)

-TDA7498 seems to be an option. Although i am confused how much power this will give mono for an 8 ohm driver. Aliexpress/Ebay all say 150W but a lot of people seem to disagree on this? Would this be a suitable option for my driver choice? I would be thinking of using the following items:
TDA7498 150W Subwoofer amplifier board Mono Audio Bass Digital power amplifier-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
and a voltage converter:
150W Boost Converter DC to DC 10 32V to 12 35V Step Up Voltage Charger Module-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group


-IRS2092S seem to be a good option too and people seem to have good experience with them. However, does this not provide too much output power? i.e. AIYIMA L15DSMD IRS2092S 250W Class D Digital Mono Amplifier Board-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group and adding the aforementioned voltage converter

Furthermore, i was also wondering if you normally use any other components in your subwoofer design: low pass filters/horn protection circuits/seperate ground circuits? All tips are welcome!

I hope you can help me and thank you in advance!

Disclaimer: i am an electronics noob :D
 
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This laptop PSU is 120W.
From 19V supply at 4 ohm load you can receive about 30-35W with T.H.D. below 1% from class D amplifier in bridge mode.
If you use DC-DC step up converter, you loose at least 10-15% for the converter itself! So, you can use about 100W after the DC-DC!
Class D amps have efficiency about 85-90%, so from that laptop PSU plus DC-DC step-up, you can receive no more than 90W of continuous R.M.S. audio power!
For 90W at 8 ohm load, you need about 36V for BTL amplifier.
For 90W at 4 ohm load, you need about 30V for BTL amplifier.
 
Why do you want to use and 8Ohm driver?

If you get a dual coil sub woofer driver, you can run it with a stereo board or 2 mono's which makes life a lot easier/cheaper.
A dual coil 4 ohm woofer has 2, 2ohm coils; which you feed very nice with 2 mono tpa3116 boards or a stereo dual chip board. @19V you will get 2x60W is 120W clean to the sub. With 24V it will be 2x100W.

Have a look at the spec.sheets of the different chips to get an idea how much power you will get.

IRS2092S needs a dual power supply and will not run from a laptop power supply.
 
Why do you want to use and 8Ohm driver?
I don't specifically want to use an 8 ohm driver, but the 4 and 8 ohm drivers seems to be better available (in the Netherlands).

If you get a dual coil sub woofer driver, you can run it with a stereo board or 2 mono's which makes life a lot easier/cheaper.
A dual coil 4 ohm woofer has 2, 2ohm coils; which you feed very nice with 2 mono tpa3116 boards or a stereo dual chip board. @19V you will get 2x60W is 120W clean to the sub. With 24V it will be 2x100W.

Would you have any recommendations for a DVC 4 ohm subwoofer? it is not necessary that my current laptop power supply is sufficient.
 
In general the bigger the woofer, the lower they go. Have a look at car subwoofers as you will find the dual coil mostly there and an other advantage of them is that most do fine in a small box as space in cars is limited.


IMO Sealed sounds best, then 4th order bandpass, bass reflex, 6th order. In home the low end will be boosted by the room gain; a sub with a flat lower end curve will sound boomy indoors.
 
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