RCF Crossover help

[teb335]

HI ,

have just been experimenting with the crossover option on the RCF AS705 sub using some test tones from the dbx website (ie that just play tones at set frequencies).

 

Noticed that even with the xover set at 80hz the 705 still played sounds upto 250hz, albeit a little quiter. Also noticed that on this xover setting 60hz tones were still coming thru the tops.

 

Does this mean the crossover is broken or am I missing the point ?

 

Thanks in advance.

[Brian]

A crossover has a property known as its 'slope' which will be expressed as xxdB per octave. xx is usually 6, 12, 18 or 24.

 

This means that for ever doubling or halving of the frequency the level drops by that amount. The crossover frequency is the frequency where the level drop starts to kick in.

 

So, in your case, the 80Hz signal will suffer hardly any drop. At 160Hz the level will have dropped, probably by 24dB, which is just a quieter signal but still very much there. At 250Hz the level will have dropped by around another 12dB. So you signal will be down around 36dB which is still quite audible.

[teb335]

Thanks very much for explaining Brian - was starting to panic that I had faulty gear.

 

I think what must have got me going is I'd previously been trying them with a driverack px, which seemed to cut the frequencies completely much closer to the xover point.

 

Sounds like ive got plenty of learning to do....but thanks again.