Sub-woofer settings

[jman74]

Cross-over: reciever manual says 120HZ should I drop to 80HZ? What does this do exactly?


Multiplex seeting on reciever:both main and sub or just sub only?

Bypass on back of Sub: Turn to max? What does this do?

Auot switch on back of sub: off or on?

 

[Halon451]

Cross-over: reciever manual says 120HZ should I drop to 80HZ? What does this do exactly?


Multiplex seeting on reciever:both main and sub or just sub only?

Bypass on back of Sub: Turn to max? What does this do?

Auot switch on back of sub: off or on?

Generally speaking, the crossover setting on your receiver is dependent on the frequency response of your speakers. THX recommends a setting of 80 Hz, which is where I have mine set - but that is because all of my speakers' lower frequency response is just a bit below that, it is not based on some arbitrary THX recommendation. The point here is to cross over the lower frequencies that the speakers cannot reproduce to the sub, which is designed to handle them.

What kind of speakers are you using? Do you know the specs? Not sure how to answer your second question without knowing more info: I have mine set to 'sub only'. I'm using bookshelf-type speakers, so I don't want LFE going to either of those. My sub is a beast that is built to pound the bejeesus out of my room by itself.

The bypass on the sub is part of your sub's built-in crossover. Since you are utilizing the receiver's crossover, you should set it to its max setting, or 'bypass', whichever it has. This reduces the potential for what's called 'cascading filters', which could lead to significant phasing issues.

The Auto switch is merely a power save feature. Setting it to 'Auto' will allow it to turn off or go into standby mode when no signal is detected. The 'on' setting will mean that it remains on, whether a signal is present or not - of course as long as the main power switch is turned on.

Hope that helps.

 

[MDS]

Main+sub or just sub

The LFE always goes to the subwoofer if one is present.

Main+sub (LFE+MAIN, Both, Double Bass - are terms used by other receivers for the same feature) means that the LFE will go to the sub, bass below the xover for channels set to Small will go to the sub, AND bass below the xover from the mains (which are set to Large) will go to the sub. That is why it is 'double bass' - the mains are playing the bass from the front channels and the sub is playing the bass from the front channels too.

Sub only means only the bass from the channels set to Small go to the subwoofer (and the LFE which always goes to the sub). So if you set the mains to Large they would play a full frequency range including low bass but none of that bass would go to the sub. This is the 'normal' case that most people use because unless your mains truly are full range (can go as low as 20 Hz) it's better to set them to Small and send the bass to the sub.

 

[jman74]

Generally speaking, the crossover setting on your receiver is dependent on the frequency response of your speakers. THX recommends a setting of 80 Hz, which is where I have mine set - but that is because all of my speakers' lower frequency response is just a bit below that, it is not based on some arbitrary THX recommendation. The point here is to cross over the lower frequencies that the speakers cannot reproduce to the sub, which is designed to handle them.

What kind of speakers are you using? Do you know the specs? Not sure how to answer your second question without knowing more info: I have mine set to 'sub only'. I'm using bookshelf-type speakers, so I don't want LFE going to either of those. My sub is a beast that is built to pound the bejeesus out of my room by itself.

The bypass on the sub is part of your sub's built-in crossover. Since you are utilizing the receiver's crossover, you should set it to its max setting, or 'bypass', whichever it has. This reduces the potential for what's called 'cascading filters', which could lead to significant phasing issues.

The Auto switch is merely a power save feature. Setting it to 'Auto' will allow it to turn off or go into standby mode when no signal is detected. The 'on' setting will mean that it remains on, whether a signal is present or not - of course as long as the main power switch is turned on.

Hope that helps.

Thanks for the info. Polk spker manual said 120HZ...is that high?

 

[jman74]

The LFE always goes to the subwoofer if one is present.

Main+sub (LFE+MAIN, Both, Double Bass - are terms used by other receivers for the same feature) means that the LFE will go to the sub, bass below the xover for channels set to Small will go to the sub, AND bass below the xover from the mains (which are set to Large) will go to the sub. That is why it is 'double bass' - the mains are playing the bass from the front channels and the sub is playing the bass from the front channels too.

Sub only means only the bass from the channels set to Small go to the subwoofer (and the LFE which always goes to the sub). So if you set the mains to Large they would play a full frequency range including low bass but none of that bass would go to the sub. This is the 'normal' case that most people use because unless your mains truly are full range (can go as low as 20 Hz) it's better to set them to Small and send the bass to the sub.

what is LFE?

 

[evilkat]

LFE = Low Frequency Effects

In this case, this is the signal the receiver sends to your sub with subwoofer audio data.

 

[head_unit]

LFE = Low Frequency Effects

In this case, this is the signal the receiver sends to your sub with subwoofer audio data.

Well not quite (as evilkat probably knows). In a 5.1 channel mix there is generally bass in ALL channels. The LFE channel carries EXTRA bass, a kind of stupid* holdover idea going all the way back to the movie "Earthquake" where they had a dedicated track that was basically vibration noise feeding a subwoofer array to shake the movie theater.
(*I say "stupid" because it just makes for more complication).

There was a listening study done and presented to the Audio Engineering Society which showed that if your crossover was at or below 80 Hz, you could not tell where the subwoofer was in the room.

But if your Polks recommend 120 Hz, they are probably too small to handle any low bass. Best to set it there, and hope your subwoofer can play that high. (We could be more helpful if you published specific model numbers).

Keep the subwoofer in front, and play around with the crossover and speaker/sub positions to see what sounds best.