# What is Amp Crossover Frequency Control for?



## c627627 (Apr 11, 2008)

Here's what is says in the manual but I don't get it:

Crossover frequency control knob (FREQUENCY)
The frequency band of the treble and the bass played back on the front and rear speakers is adjusted. Setting range: 50 Hz to 250 Hz


For example here's what the manual says about Bass boost knob: The bass boost circuit is employed to play back the deep bass on the front and rear speakers.

I deciphered that one to mean that if speaker sound is distorted due to excessive power, turn the Bass boost down.


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## c627627 (Apr 11, 2008)

*bump*


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## MadMaxSE-L (Oct 19, 2006)

Ok, well first of all let me tell you to leave the bass boost know turned *all the way down* - you probably don't need it if the rest of your system is tuned correctly...

2ndly, do a search on here for "crossover" and see what you come up with; you should find more than enough info to help answer your question.

-Matt


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## Nitin (May 28, 2008)

hi guys my first reply on the forum - been a lurker here for a while - so i hope that this reply isnt too much of nonsense

well basically the crossover would restrict the frequencies that a speaker plays - lower frequencies are supposed to be played back by speakers that are capable of playing back those lower frequencies - so you restrict the frequencies that are played back by adjusting the control to limit exactly what the speaker plays - the frequency you set it at is not exactly a total cutoff point - ie if you set a low pass of 80hz on your sub - that doesnt mean that it wont play frequencies that are higher than 80hz - what it means that these are reduced according to what is known as the slope - for example if the slope is 12db's per octave then at a low pass of 80hz you will still hear between 80hz and 160 hz at a reducing rate but 160hz itself is down by 12db's and then 320hz would be down by 24db's but its still being played by that speaker - but the odds are you wont hear those frequencies anyway cos a drop of 3db's will halve the measured level that you hear it by (perceived halving of any sound would be at around 10db's lower)

a bass boost is a different animal altogether - it will increase a particular frequency (normally 45/50hz) by whatever you turn the control knob up to so its a form of equalizer for low frequency - the problem with using too much of this bass boost is that at the frequency it works at for every 3db you increase by you are making the amp work twice as hard for that frequency as opposed to all the other frequencies the amp is going to play - so each time you add 3db's you strain the amp at that point - so generally that is how it is with equalizers too which is why most people say with equalizers it is better to cut rather than to boost a particular frequency so as to not make an amp work too hard at a particular frequency 

hope that some of this stuff makes sense


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## c627627 (Apr 11, 2008)

It makes sense mathematically. 

The manual states similar technical explanations but then the manual offers this practical comment for the definition of bass boost: _"if speaker sound is distorted due to excessive power, turn the Bass boost down._"

However, it does not offer any practical follow up like that when talking about Amp Crossover Frequency Control knob.


These are my components: Pioneer TSD-1720C 


This is my amp with those controls: Panasonic CY-PA2003U


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## gijoe (Mar 25, 2008)

Search for "passive" and "active." If you are using those comps with the passive crossovers that were included you don't have to worry about the crossover on the amp so much. The passive crossovers will figure this out for you. You could set the amp to 80-100 just so those freqs don't ever go to the passives and end up just turning into heat. Others are more knowledgeable. Try searching some keys words.


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