6,5" vs 8" vs 12" What will play louder?

Cone area is king when all other variables are constant. 

Johnniz said:

Hi.

With a 120W RMS amp, 240w max, what would play the loudest from these 3 options:

12" 275W RMS Sensitivity: 92dB

8"  150W RMS Sensitivity: 90,2dB

6,5" 100W RMS Sensitivity: 88.8dB

I would make the enclosure per the manufacturers recommendations

I already have the 12" sub and the amp, but I think it is severely under powered.

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the enclosure is what matters so your enclosure and your sub positioning is bad if you arent getting good output. Sealed wont do sh*t, ported you need to build it according to your vehicle acoustics so get the enclosure game up. You always want the port firing to a solid wall to the rear as well.

When it comes to chasing the 'how loud' factor, then the laws of physics come into play but in simple terms, cone area and bigger box size will give you more bass.

You can go loud with sealed as well, but if your primary aim is efficiency with a single subwoofer, then go the largest driver with the biggest ported box you can accommodate in your trunk area and you will be grinning all the way home!

The ported enclosure also  makes the box more efficient and requires less power to get the required result.

DRBOOM said:

When it comes to chasing the 'how loud' factor, then the laws of physics come into play but in simple terms, cone area and bigger box size will give you more bass.

You can go loud with sealed as well, but if your primary aim is efficiency with a single subwoofer, then go the largest driver with the biggest ported box you can accommodate in your trunk area and you will be grinning all the way home!

The ported enclosure also  makes the box more efficient and requires less power to get the required result.

View attachment 5703

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bigger is not always louder, It really depends on the sub's parameters. I've shrunk boxes and gained all across the board in DBs while shrinking port area keeping the same tuning.  if you lose cone control with too big of a box you wont get that loud. There's a limit depending on the sub. Another thing is bandwidth and peakiness, bigger boxes will make a bigger peak in frequency response, when you RTA the setup you'll see the peak flatten out drastically as you shrink size to proper airspace for the sub and you can put more power to it and it'll still be just as loud but way better bandwidth.

120 rms watts is wayyyyy to little power for a sub. Hell I run that to my mids/highs.

Boomin_tahoe said:

120 rms watts is wayyyyy to little power for a sub. Hell I run that to my mids/highs.

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Figure impedance rise as well and that makes it more like 40 or 50watts to the sub  :banghead:

Johnniz said:

It was the amp that came with the sub unfortunately. I know it is not very powerful, but it is all I got at the moment.

It is this one: https://www.maxaudio.com.my/amplifier/6642-jbl-gt5-a402-gt-series-40w-rms-2-channel-car-amplifier.html

And the 12" I already got is: https://www.jbl.com.sg/car-subwoofers/GT5-1204BR.html

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You need an amp that is rated for at least 600w rms at 4 ohms to properly power that sub. 

Johnniz said:

Yeah, I know I need something more powerful to power it properly, just asking if it would be better to buy a cheap 6,5" or 8" rated 100-150W RMS, and if that would be louder than to power the 12" with the same amp?

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Nope, keep what you have and get a better amp. The JBL GT5 is a quite capable entry level sub if you put it in the right box with the right amp. 

Johnniz said:

Yeah, I know I need something more powerful to power it properly, just asking if it would be better to buy a cheap 6,5" or 8" rated 100-150W RMS, and if that would be louder than to power the 12" with the same amp?

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the 6.5 and 8 will be fully powered but you literally just gave up 70% to 55% cone area, not to mention any kind of Xmax as well so you are actually losing A FUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUCK ton of output by doing so.

only way the smaller sub would be louder is if the smaller sub was higher RMS rating like 500-750 RMS(and you are feeding the sub double its RMS ratings 1000-1500), stronger motor, higher excursion and inside a huge giant perfect efficient box. Meanwhile the bigger sub is cramped inside a box waaay too small for it and its on very little power. That would be the only situation where a 6.5 or 8 might beat a 12.

18's or nothing fam 

Uh oh dick taker is back....