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 Question about Woofer Ohms and Watts

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TSvinothrao84
post Jun 30 2020, 05:13 PM, updated 4y ago

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I wanted to use car woofer as Home Hifi woofer and i wanted to get those 2.1 mini amplifier that can be found in Shopee. The sub output rated by the mini amp is 100w RMS. Not sure at what Ohm. It says able to support from 4ohm to 8ohm.

Question is, if i buy a car woofer that is rated at 300w RMS 4 ohm dual voice coil, does that mean if i connect the woofer to the amp via 8 ohm wiring, does the woofer cut in half power to 150w?

I mean can the 300w 4ohm DVC woofer connect to 100w amp via 8ohm woofer wiring?

Thanks.
BelaCHAN
post Jun 30 2020, 05:31 PM

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QUOTE(vinothrao84 @ Jun 30 2020, 05:13 PM)
I wanted to use car woofer as Home Hifi woofer and i wanted to get those 2.1 mini amplifier that can be found in Shopee. The sub output rated by the mini amp is 100w RMS. Not sure at what Ohm. It says able to support from 4ohm to 8ohm.


Thanks.
*
Assume at 8 Ohm.

At 4 ohm, its gonna be about 50 - 70Wrms,
assumming the RMS can be trusted =D
fireballs
post Jun 30 2020, 05:48 PM

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http://www.bcae1.com/spkrmlti.htm
TSvinothrao84
post Jun 30 2020, 06:08 PM

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QUOTE(BelaCHAN @ Jun 30 2020, 05:31 PM)
Assume at 8 Ohm.

At 4 ohm, its gonna be about 50 - 70Wrms,
assumming the RMS can be trusted =D
*
What about the woofer? Can i say its 150w 8ohm? That means the mini amp can still push using its 100w 8ohm?
TSvinothrao84
post Jun 30 2020, 06:10 PM

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QUOTE(fireballs @ Jun 30 2020, 05:48 PM)
Wow so complex. Haha

I just want to know about the final wattage from 300w 8ohm. Will it be 150w?
fireballs
post Jun 30 2020, 06:31 PM

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i suppose you are looking at this amp
https://www.lazada.com.my/products/tpa3116d...2981766493.html

go to the datasheet at https://www.ti.com/product/TPA3116D2#produc...tails##features

then you will see its
50+50W at 4ohm

means ngam your application. they mix two channel to form 100W

err what is a subwooffer speaker with dual voice coil?

This post has been edited by fireballs: Jun 30 2020, 06:31 PM
danielmckey
post Jun 30 2020, 06:36 PM

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You just need to match you subwoofer power with the amp. If your amp is more power than subwoofer. The sound will be distorted.
TSvinothrao84
post Jun 30 2020, 06:41 PM

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QUOTE(fireballs @ Jun 30 2020, 06:31 PM)
i suppose you are looking at this amp
https://www.lazada.com.my/products/tpa3116d...2981766493.html

go to the datasheet at https://www.ti.com/product/TPA3116D2#produc...tails##features

then you will see its
50+50W at 4ohm

means ngam your application. they mix two channel to form 100W

err what is a subwooffer speaker with dual voice coil?
*
Ohh that's great bro. I didn't know about the data sheet.
The woofer i looking at is either this.

Rockford Fosgate R2D4-12
KENWOOD KFC-W3514DVC

Do you know if they supported for Nobsound 2.1 50w x2 + 100w for woofer.

Thanks a lot.
TSvinothrao84
post Jun 30 2020, 06:44 PM

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QUOTE(danielmckey @ Jun 30 2020, 06:36 PM)
You just need to match you subwoofer power with the amp. If your amp is more power than subwoofer. The sound will be distorted.
*
The amp is rated 100w output and the woofer rated around 300w for 4ohm DVC. Do u think the amp can push the woofer? Should it be wiring at 8ohm or 2ohm?

Thanks.
danielmckey
post Jun 30 2020, 06:51 PM

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QUOTE(vinothrao84 @ Jun 30 2020, 06:44 PM)
The amp is rated 100w output and the woofer rated around 300w for 4ohm DVC. Do u think the amp can push the woofer? Should it be wiring at 8ohm or 2ohm?

Thanks.
*

fireballs
post Jun 30 2020, 06:57 PM

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https://rockfordfosgate.com/products/details/r2d4-12/
https://manual.kenwood.com/en_contents/atta...load/1000005943


your amplifier price not bad.
https://www.lazada.com.my/products/tpa3116-...1890454052.html

from datasheet should best suited to 2ohm for the 100W max.
https://www.ti.com/product/TPA3116D2#produc...ls##description

so your choice of dual voice coil sub is correct.
one subwoofer is sufficient.

This post has been edited by fireballs: Jun 30 2020, 07:02 PM
TSvinothrao84
post Jun 30 2020, 07:24 PM

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QUOTE(fireballs @ Jun 30 2020, 06:57 PM)
https://rockfordfosgate.com/products/details/r2d4-12/
https://manual.kenwood.com/en_contents/atta...load/1000005943
your amplifier price not bad.
https://www.lazada.com.my/products/tpa3116-...1890454052.html

from datasheet should best suited to 2ohm for the 100W max.
https://www.ti.com/product/TPA3116D2#produc...ls##description

so your choice of dual voice coil sub is correct. 
one subwoofer is sufficient.
*
Thanks for the helpful response bro.

But I'm little confused here. U mentioned 2 ohm.
So that means i need to set subwoofer wiring as 2 ohm? Will the woofer wattage increase coz of 2ohm?
And the 100w from the mini amp will output 2ohm or 4ohm?

Thanks.

fireballs
post Jun 30 2020, 08:13 PM

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QUOTE(vinothrao84 @ Jun 30 2020, 07:24 PM)
Thanks for the helpful response bro.

But I'm little confused here. U mentioned 2 ohm.
So that means i need to set subwoofer wiring as 2 ohm? Will the woofer wattage increase coz of 2ohm?
And the 100w from the mini amp will output 2ohm or 4ohm?

Thanks.
*
2ohm means its easier to push, less resistance.
to get your full 100W, you need low ohm and high voltage.
if you use the standard 12V, most likely you wont get full 100W.
recommend to use 24vdc.

TSvinothrao84
post Jun 30 2020, 10:52 PM

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QUOTE(fireballs @ Jun 30 2020, 08:13 PM)
2ohm means its easier to push, less resistance.
to get your full 100W, you need low ohm and high voltage.
if you use the standard 12V, most likely you wont get full 100W.
recommend to use 24vdc.
*
I just purchased 24v 5a adapter. But I'm just wondering, the sub output is max 100w at 4ohm. So if i wired the woofer at 2ohm, then the woofer surely needs more than 100w right? Please correct me if I'm wrong.

Thanks.
Oldskolboyz
post Jul 2 2020, 10:19 PM

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QUOTE(vinothrao84 @ Jun 30 2020, 05:13 PM)
I wanted to use car woofer as Home Hifi woofer and i wanted to get those 2.1 mini amplifier that can be found in Shopee. The sub output rated by the mini amp is 100w RMS. Not sure at what Ohm. It says able to support from 4ohm to 8ohm.

Question is, if i buy a car woofer that is rated at 300w RMS 4 ohm dual voice coil, does that mean if i connect the woofer to the amp via 8 ohm wiring, does the woofer cut in half power to 150w?

I mean can the 300w 4ohm DVC woofer connect to 100w amp via 8ohm woofer wiring?

Thanks.
*
Sub.. 300w RMS @ 4 Ohm DVC mean 150w RMS @ 4 Ohm for each VC..
Amp.. Max 100w RMS @ 4 Ohm equal to 50w RMS @ 8 Ohm.. if output rate 4 Ohm to 8 Ohm mean not stable to run below 4 Ohm..

Based on the above Sub Spec.. You required 600w RMS @ 4 Ohm amp or stable amp can run 300w RMS @ 2 Ohm.. Coz what ever wiring you use, sub pwr still maintain @ 150w RMS per VC either run at 2 or 8 Ohm.. Only amp pwr output can be increased or decreased depend wiring..

 

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