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Crossover Frequency Question

sjp1966

Novice Member
I am looking at the manual of my Harman Kardon Amp and it says the following.

The available choices at which point low-frequency information will be sent to the subwoofer (or to the Front Left/Right speakers in case subwoofer is set to OFF), rather than to the speaker channel, are 40Hz, 60Hz, 80Hz, 100Hz, 120Hz and 200Hz. Pick the choice that is identical to the information
for the speakers, or if an exact match is not possible, pick the closest choice that is ABOVE the speaker’s lowfrequency limit to avoid the creation
of a low-frequency “hole” where your system will have no bass information.


I have KEF Q4 front and rear speakers and it states that :

Crossover frequency 250 Hz - 2.8kHz

At the moment my AMP is set to 60Hz, but i read this as i need to set my AMP to 200Hz, is this correct or am i reading this totally wrong?

regards
 

Cable Monkey

Novice Member
You are reading it wrong. The crossover point from a bass management point of view is the frequencies directed to a sub rather than your speakers. The crossover in your speakers is the electronics that splits your signal between the woofer and tweeter in the speaker itself.
Do you have a sub?
 
A

alphabet

Guest
As your manual states "pick the closest choice that is ABOVE the speaker’s lowfrequency limit"

That means above the lowest frequency that you speaker can reproduce, which in this case is 42Hz. The frequency you refer to is the frequency at which the speaker crossover send signals to the midrange driver(from 250Hz to 2.8KHz) That means that signals below 250Hz is sent to the woofer and signals 2.8KHz and above are sent to the tweeter.

You can experiment with the LFE crossover between 60 and 100Hz with your front speakers set to large and then the same with the speakers set to small until you find the sound you like.

The Q4s don't play really low, but your sub will fill the gap perfectly.
 
J

Jake James

Guest
Hi sjp1966

The 250 - 2.8 is the speakers crossover freq. not the lowest freq that the speaker will go down to (which is what you need).

below is data from the kef website. the bit in bold is the bit you need.

Frequency response at 15° horizontally off axis ±3 dB ......42 Hz - 27 kHz
Crossover frequency ................................................250 Hz - 2.8kHz

i.e. set your amps crossover to either 40Hz or 60Hz (have a play)

regards

JJ
 
42hz is the point were it has lost -3db output but it might start to drop about 80hz so best let the sub do 80hz and below
 

sjp1966

Novice Member
Cable Monkey said:
You are reading it wrong. The crossover point from a bass management point of view is the frequencies directed to a sub rather than your speakers. The crossover in your speakers is the electronics that splits your signal between the woofer and tweeter in the speaker itself.
Do you have a sub?
HI, Thanks for the reply.

Yes i have a sub, the set up is 2 pairs of KEF Q4 (fronts and rears) a Q6c Centre and a PSW2500 Sub
 

sjp1966

Novice Member
alphabet said:
As your manual states "pick the closest choice that is ABOVE the speaker’s lowfrequency limit"

That means above the lowest frequency that you speaker can reproduce, which in this case is 42Hz. The frequency you refer to is the frequency at which the speaker crossover send signals to the midrange driver(from 250Hz to 2.8KHz) That means that signals below 250Hz is sent to the woofer and signals 2.8KHz and above are sent to the tweeter.

You can experiment with the LFE crossover between 60 and 100Hz with your front speakers set to large and then the same with the speakers set to small until you find the sound you like.

The Q4s don't play really low, but your sub will fill the gap perfectly.
Ok, so if i play between 60 and 100hz on the crossover my Q4's will take "some" of the bass? is that right? i will give that a try.
 

sjp1966

Novice Member
Jake James said:
i.e. set your amps crossover to either 40Hz or 60Hz (have a play)

regards

JJ
I thought i was reading it wrong :), yes i shall have a play, i think ive sussed the levels of th eother speakers its the sub im working on now.
 
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