12db or 24db octave?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=26360
Printed Date: May 29, 2024 at 5:43 AM
Topic: 12db or 24db octave?
Posted By: kure
Subject: 12db or 24db octave?
Date Posted: February 12, 2004 at 4:49 PM
whats the difference i saw a RF puch amp 100 x 4 watts rms thats 12db HP/LP crossover and a RF Power 110 x 4 watts rms thats 24db Hp/LP crossover is the 24db better , louder etc???? https://www.etronics.com/product.asp?stk_code=roc801x&store=&catid=306 https://www.etronics.com/product.asp?stk_code=roc851x&store=&catid=306
Replies:
Posted By: mark241
Date Posted: February 12, 2004 at 5:07 PM
what it means is that the slope of the crossover is steep than the 12 db. For each consecutive octave up or down depending on if it is set on high or low pass you will lose 12 db or 24 db depending on which one you buy. The 12 db is less abrupt than the 24db. Frequencies after (low pass) the crossover setting will be a little louder with the 12 db than with the 24. I hope this helps a bit.
Posted By: forbidden
Date Posted: February 12, 2004 at 5:15 PM
There is usually a couple of differences in these amps, one is warranty for us in Canada, 1yr. vs. 2 yr. The second difference is the power supplies, the Power series amp has a larger power supply to handle difficult loads with more precision and capabilities. A 24db slope on the crossover is usually referred to as a brick wall filter, nothing gets by it that is not supposed to. Sound does not end magically at the crossover point, it is rolled of gradually, either at 12db per octave in this case or 24 db per octave. Imagine that you are doing stopping tests in a car. Car one takes 200 feet to stop from 100mph. Car two takes 150 feet to stop from 100 mph. Both cars do the same speed, both cars are identical, the only difference is the braking system, one can stop quicker than the other from the same point in which the brakes are applied. In this case the brakes are the crossover and as the sound is rolled off above or below the crossover point, which is the stopping line from 100mph. One of the guys, probably Dyohn will post up the tech side of it, but I'll let you get the basic understandings from this. I personally use 24db slopes on all of my systems designed for sq.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: DYohn
Date Posted: February 12, 2004 at 5:29 PM
Hey Rob. Here's my technical input on this one; You said it!  No need for anything else.
Posted By: kure
Date Posted: February 12, 2004 at 8:12 PM
so go with the 24db then?
Posted By: forbidden
Date Posted: February 12, 2004 at 8:15 PM
That would be a good move!
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Top Secret, I can tell you but then my wife will kill me.
Posted By: TDean
Date Posted: February 12, 2004 at 8:34 PM
A 12 db slope will let more upper bass content pass through. A sub that fires directly into the listening environment is most likely to benefit from a 24 db/octave slope.
Posted By: kure
Date Posted: February 12, 2004 at 9:39 PM
yeh but that amp will be playin midrange an highs no bass a jbl600 will play bass so in that case will it make a big difference the 12db slope is cheaper
Posted By: kure
Date Posted: February 12, 2004 at 9:42 PM
and is teh difference in SQ noticable
Posted By: TDean
Date Posted: February 12, 2004 at 11:06 PM
If you use a 24db for hp filters, it will limit bass and you can play increased volume with less distortion.
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