Brahma power requirements

[vhspowerhouse 10+ year member]

I apologize if this has already been asked, but I could find nothing on it. I am looking at the brahma and the power for full excursion with various box sizes (on the power handling chart they provide). My question is would a smaller box with more power be louder than a larger box with less power. They have a 2.1 cuft i think box for a 12 only needing 500w to reach full excursion! Seems to me if it is at full excursion in both scenarios it should be just as loud in both.

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[slick rick 10+ year member]

im looking at these #'s also. might want to throw a brahma on my jbl600.1 anyway if you get a brahma i gotta hear it!

 

[killcrap 10+ year member]

http://www.adireaudio.com/Files/BrahmaPowerHandling.pdf

 

[hoss 5,000+ posts]

a smaller box is going to be louder, but the SQ will be diminished. the smaller box will also give you a hump in the response of the woofer.

 

[squeak9798 5,000+ posts]

a smaller box is going to be louder, but the SQ will be diminished. the smaller box will also give you a hump in the response of the woofer.

And the larger box will have better low frequency extension.

 

[derek33 10+ year member]

http://www.adireaudio.com/Files/BrahmaPowerHandling.pdf

It sais if the box is around 6 ft^3, you only need around 400 watts to reach full excursion. What if you had a box around that size (6ft^3) and you put more watts into it... would it blow or damage the woofer?

 

[audiolife 5,000+ posts]

lol it would be clacking from bottoming out which would be rather hard on its suspension

 

[vhspowerhouse 10+ year member]

Can you explain why the smaller box would be louder please?

 

[slick rick 10+ year member]

i believe he means due to the peak in output in the higher bass (like above 50hz) it will appear louder. i say go big with less power and get some nasty low end and just get a good set of components.

 

[hoss 5,000+ posts]

as your box size decreases your Qtc increases. when you Qtc increases the dampening effect of the box on the woofer decreases, so the woofer has less resistance to fight against it.

also, this higher Q increases the roll off slope of the low end raising your F3.

for instance, take a woofer in a sealed enclosure with a Q of 0.7(ideal for car applications), this will give us a reference peak SPL to base off of. this Qtc wil also yield us a roll off slope of roughly 10.6Db/octave on the low end, yielding an F3 of 35Hz(remember, this is all based on an unspecified woofer)

take that woofer and put it in a box with a Qtc of 0.9 and the results are as follows: .69Db increase in output, 11.95Db/octave roll off, and an F3 of 39Hz.

same woofer with a 1.0 allignment gives: 1.25Db gain in output, 12.08Db/octave roll off, and an F3 of 43Hz

and to illustrate an extreme, the same woofer in a Qtc allignment of 1.5 gives: 4Db increase in output, a 13.96Db/octave slope, and an F3 of 64Hz.

box size is a compromise of several things, as you can see. smaller boxes boost your power handling a bit, and give better SPL output, but they compromise your SQ at the same time. larger boxes are going to sound better, and yield better low end response, but they are going to have slightly diminished output.

 

[eric77 10+ year member]

a smaller box is going to be louder, but the SQ will be diminished. the smaller box will also give you a hump in the response of the woofer.

I thought larger boxes were ussually louder and smaller boxes had better sq.

 

[vhspowerhouse 10+ year member]

Thanks for the info. So would such a low power/large box application be any better/worse/same for say an idmax? I love massive low end, and have 8's in the doors for 50 up and a 5 1/4 component set. I just want VIOLENT, clean lows.

 

[hoss 5,000+ posts]

I thought larger boxes were ussually louder and smaller boxes had better sq.

larger ported boxes are louder than smaller ported boxes, but sealed works the other way around. SQ with a ported box usually occurs with a moderate sized box, and is more dependent on the tuning freq used.

sealed boxes however, work as described--small sealed yields better output and diminshed Sq and a higher F3, larger boxes yields better Sq, less output, and better low end response

 

[hoss 5,000+ posts]

Thanks for the info. So would such a low power/large box application be any better/worse/same for say an idmax? I love massive low end, and have 8's in the doors for 50 up and a 5 1/4 component set. I just want VIOLENT, clean lows.

no prob, i like to help when im able to //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

it would be about the same for an idmax, your best bet would be to find one of the online calculators designed to calculate the Qtc and find an allignment that works best for you. most car stereos aim for an allignment around .707, but anything from about .6 to .707 would be good for SQ.

however, if you want violent lows, i would suggest a well designed vented enclosure //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif . i have always had good luck with them, been able to shake my steering column at 20Hz //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[vhspowerhouse 10+ year member]

What frequency might you suggest aming for as far as tuning a ported box. I want it to sound good up to 50hz and go ungodly low. Box tuning and qts are still new to me so I don't have a great grasp on them.