Hi Level v Low Level Connections

nwhitta

Active Member
I am little confused about the merits of connecting a subwoofer by its high level connection or its blow level connection.

I know that REL recommend using the high level connection from the speaker out connection on the back of the amplifier as this ensures the subwoofer receives exactly the same signal as the main speakers.

Many people on this forum prefer to use the low level connection from the LFE channel on the AV receiver. If the crossover is set at 80Hz, this relieves the main speakers of the burden of low frequency reproduction which can improve sound quality (and allow higher volume). I can understand that the LFE connection can be effective when playing DVDs recorded with an 5.1 sound utilising the LFE channel.

However my question is, does this LFE connection also work when playing two channel stereo CDs or, if I connected the subwoofer via the low level connection only, would I then lose all programme material below 80Hz?
 

Neil Davidson

Well-known Member
AVForums Sponsor
The crossover on most receivers will be designed so that all data below the crossover point is sent to the sub, not just the LFE channel. As a result you will not lose any information and will benefit as you describe in your post.

Neil
 

Nimby

Distinguished Member
Could a sub be connected simultaneously to both LFE on the AV receiver and Pre-out on a separate stereo preamp?

Many subs have two phono input sockets so it is physically possible to make the connections.

Any potential dangers from floating voltages or double earthing problems?
 

nwhitta

Active Member
ceenhad said:
The crossover on most receivers will be designed so that all data below the crossover point is sent to the sub, not just the LFE channel. As a result you will not lose any information and will benefit as you describe in your post.

Neil
Thanks Neil,
Will this also apply when using Pure Direct mode on my Denon 2805 receiver?
 

Neil Davidson

Well-known Member
AVForums Sponsor
When you use direct mode on any receiver you bypass all of the careful setup correction that you have applied to the system in order to get "unprocessed" sound from the system.

I can assure that this almost always actually decreases the sound quality (unless the system has been very badly configured) and so should be avoided.

Neil
 

Neil Davidson

Well-known Member
AVForums Sponsor
Nimby said:
Could a sub be connected simultaneously to both LFE on the AV receiver and Pre-out on a separate stereo preamp?

Many subs have two phono input sockets so it is physically possible to make the connections.

Any potential dangers from floating voltages or double earthing problems?
Never actually tried this but as long as the components are on the same ring and you ensure that one is switched off fully before switching the other on I don't see any problems.

Switching both on together would almost certainly be a bad idea though ;)

Neil
 

Knyght_byte

Novice Member
ceenhad said:
When you use direct mode on any receiver you bypass all of the careful setup correction that you have applied to the system in order to get "unprocessed" sound from the system.

I can assure that this almost always actually decreases the sound quality (unless the system has been very badly configured) and so should be avoided.

Neil

doesnt on my 3803...lol

the Pure Direct mode works a treat, but then i do use full range floorstanders carefully sited for stereo as well as movies....
(well, when i didnt have my GR10's i used them set up like that anyhow...lol..atm the S6's are sited somewhat closer to a wall...heh..the GR10s take precedence!)
 

Cable Monkey

Novice Member
ceenhad said:
When you use direct mode on any receiver you bypass all of the careful setup correction that you have applied to the system in order to get "unprocessed" sound from the system.

I can assure that this almost always actually decreases the sound quality (unless the system has been very badly configured) and so should be avoided.

Neil
Different recievers work different ways and you cannot say that with any confidence about any setup other than your own. There would be very specific circumstances when a direct mode or pure direct mode is used, almost always with music. It would be for stereo where no intervention should be required or multichannel music where you might set up your parameters on the player itself. Both of these should (and in my case does) result in an improvement in quality, though that can be quite subtle. If not you are either not using the direct mode appropriately or you have an amp (like a 2805) that removes bass management in pure direct mode thus disconnecting your sub. Also while I understand what ceenhad was getting at he actually had it juxtaposed. Pure direct is the removal of any processing at the amp, it simply becomes a straight through amp, what goes in simply comes out uniformly XdB's louder.
 

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