Sub Frequency & Phase, help please

[Nick_Shepherd]

What do these do, and how best do I set it?

Alumni 9 Sub manual says if LFE is selected, then the amp will deal with the frequency?

What shuld phase be set to? (dont know what it does!)

Have phone lead from old amp to sub.

Thanks!

 

[Anonymous]

The sub specialises in reproducing frequencies below a certain value - say 120 Hz.

Your main speakers may however go down to 70Hz, meaning both your sub and main speakers are reproducing the sounds where they overlap.

This may mean the sound is overpowering or boomy when noises at these frequencies occur. Therefore you can set your amp to control which frequencies to send to the sub by setting a value where your main speakers run out avoiding this overlap.

Phase refers to whether the sub if firing at the same time as the main speakers - i.e. the cones moving back and forth. A rule of thumb is vary the phase switch and settle for the position in which the bass is least noticeable - more noticeable suggests you are detecting the bass more on its own because it is not quite in snyc with the main speakers; you should still detect the bass but it should seem more as though it is coming from the main speakers as though they go that low themselves.

These are simplistic answers but I hope they help you with the basic ideas (no pun intended).

 

[Nick_Shepherd]

thanks shreddy. that dose help. is it right that by selecting LFEon the sub, the ampcontrils the frequency?

 

[Anonymous]

Yes, LFE is the name of the '.1' channel on a 5.1 surround soundtrack (low frequency effect).

Although your sub may have its own frequency filter and controls, it will be bypassed if you connect it via the rca (phono) from your av amp as the amp will control the frequencies allowed to go to the sub and other speakers.

The reason subs also have on board frequency settings is if you connect them up using speaker level i.e. treating it as a conventional speaker; the sub then gets the whole signal which its own filter then is set to allow only relevant frequencies through.

 

[Nick_Shepherd]

thanks again shreddy. most helpful!

So if connecting with phono, i dont worry about frequency setting, but, do i need to adjust phase or is it all over ridden?

 

[Anonymous]

The frequency setting on your sub will make no difference as the circuitry is not engaged when using the lfe method; although some people will tell you to turn the sub's frequency knob all the way up (depending on the sub's design).

However phase is still adjustable. You need to experiment with this once you are used to the system. Adjust it so bass is deep and tight but not boomy. If there is too much boom the phase can be used to curb it although I'm afraid it is not a simple immediate right or wrong setting.