12DB-24DB Slope?

[Patthehat033 10+ year member]

Hey,

I have a RF T5002 and it has a 12db-24db slope on it. I have read some websites and I am still kind of confused how this works.

It says it increases/decreases 12db or 24db (depending on which one I have it set on) per octave. But what frequency is it basing that off of?

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[trumpet 5,000+ posts]

The crossover filters are to protect your speakers and to keep bass at the subwoofer and not have the subwoofer playing vocals. If you have a low pass crossover of 100 Hz on your subwoofer that means at 100 Hz the level is reduced 3 dB. With a slope of -12 dB, at one octave higher, or 200 Hz, the level is down another 12 dB for a total of -15 dB. You would almost never use a 100 Hz 12 dB/octave slope on a subwoofer because you can still hear a lot more than just bass with a slope that shallow.

 

[bubbagumper6 5,000+ posts]

The difference between 12db/octave and 24db/octave is simply the slope at which the response curve falls off.

In this image the crossover frequency is somewhere around 60Hz and the slope of the line to the left of it is what you're changing. The higher the number the faster it will fall. (Image borrowed from Basic Car Audio Electronics)

(Also note the response pictured is a high pass filter, your low pass filter works the same way but it's mirrored horizontally)

 

[Patthehat033 10+ year member]

The crossover filters are to protect your speakers and to keep bass at the subwoofer and not have the subwoofer playing vocals. If you have a low pass crossover of 100 Hz on your subwoofer that means at 100 Hz the level is reduced 3 dB. With a slope of -12 dB, at one octave higher, or 200 Hz, the level is down another 12 dB for a total of -15 dB. You would almost never use a 100 Hz 12 dB/octave slope on a subwoofer because you can still hear a lot more than just bass with a slope that shallow.

Okay that makes sense! But then if say we had the x-over at 100hz, would the db level increase as the hz got lower?

 

[Patthehat033 10+ year member]

The difference between 12db/octave and 24db/octave is simply the slope at which the response curve falls off.
In this image the crossover frequency is somewhere around 60Hz and the slope of the line to the left of it is what you're changing. The higher the number the faster it will fall. (Image borrowed from Basic Car Audio Electronics)

(Also note the response pictured is a high pass filter, your low pass filter works the same way but it's mirrored horizontally)

This is a high pass crossover correct? Because you said the x-over frequency was 60hz, but the maximum power in the image is at like 1000hz.

 

[ahole-ic]

This is a high pass crossover correct? Because you said the x-over frequency was 60hz, but the maximum power in the image is at like 1000hz.

It is a high pass but maximum power is with the "enhanced Q crossover" at 100hz.

 

[bubbagumper6 5,000+ posts]

This is a high pass crossover correct? Because you said the x-over frequency was 60hz, but the maximum power in the image is at like 1000hz.

Yes...

(Also note the response pictured is a high pass filter, your low pass filter works the same way but it's mirrored horizontally)

 

[Patthehat033 10+ year member]

It is a high pass but maximum power is with the "enhanced Q crossover" at 100hz.

Thanks for pointing that out to me. What type of crossover is on most modern amplifiers? Or is there no way to really tell?