need an explanation

[hargenoff 10+ year member]

i know this might sound cheezy or stupid, but this is what the site is for is to learn right!!! anyway...the gains on my 4-channel amplifier read 30hz and 4khz and since there is a 2 sets of these i assume one powers the fronts and one powers the rear. the power rating on the amp is 4x80 set at 4 ohms, and is powering a set of mbquarts that are about 60-130 watts, in the front and Boston Acoustics that are about 100 watts in the rear. here is the question...what does the 30hz and 4khz mean? Does the 30hz mean a lower pass frequency or vice versa? What about the 4khz? How do I control them to get good SQ out of all my speakers w/o blowing them? It seems everytime I try to adjust them it gets louder, but more of a high pitch sound, louder vocals w/o much bass help explain what 30 hz and 4khz does for the speakers?

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[unrealii 10+ year member]

Those adjustments are the cut off frequencies. 30Hz is a very low frequency, something which a subwoofer would be producing. 4kHz is for the tweeters, or at least that is where my tweeters start at. I'm not very good at explaining, I'm sure someone else can explain it better.

 

[hargenoff 10+ year member]

that helps a little. anybody else explain more in depth?

 

[iceteebone 5,000+ posts]

i'll give it a try i guess. on your amp there should be a setting for high pass. that means that any frequency below what that is set at will not be heard. if you set it at 50 hz. anything under 50 won't be heard. that's why when you turned it up all you heard were vocals. depending on the size of your speakers i would set it at 80-100 hz. anything lower would be to low for your speakers. 30 hz. is subwoofer range.

 

[hargenoff 10+ year member]

so does this mean I want my speakers in the front (w/tweeters) set at higher Hz to hear more vocals and my rear speakers to be set at a lower Hz to get more bass out of them?

 

[helotaxi 5,000+ posts]

so does this mean I want my speakers in the front (w/tweeters) set at higher Hz to hear more vocals and my rear speakers to be set at a lower Hz to get more bass out of them?

You want to keep really low frequencies from getting to speakers intended to play higher frequency sounds. The low notes can damage the speakers. This goes not just for your front speakers, but your rear ones as well. Setting the cutoff higher doesn't add to the highs, it just gets rid of the lows. 80-120 Hz is about where you want to set them. Any lower and you will risk damaging the speakers and any higher and you will be missing the midbass in the music. Your rear speakers are not going to give you real bass. If you want solid low bass you will need a sub.

 

[hargenoff 10+ year member]

ok cool....one more thing and i think i got this thing figured out......my amp has three different settings I can use to power the speakers Hp Lp and Full Range. So does this mean I want to keep the front speakers at Hp and the rear at Lp? or do I keep both set at Full Range? and keep the gains set between 80-120hz? Or am I just way off course in my understanding?

 

[helotaxi 5,000+ posts]

You want both your front and rear set to HP or High Pass. This is a filter that gets rid of the frequencies below the cutoff. The "gain" does not have a freq range, what you are looking at is the selector knob for the filter frequency for the High or Low pass filter. If the gain has any markings on it at all it will be in voltage with the higher numbe requalling a lower gain setting.