Connecting Pre-outs (1 Viewer)

[Dave Nibeck]

Posted in another thread with no response. Maybe someone here can help.

Have a Denon 4802 set up with 6.1 speakers. Looking to add a sub to the rear. The amp has 2 sets of pre-outs for the rear.

Does the speaker size (in setup) dictate what info gets sent to the pre-outs?

Can I use a Y adapter to combine the left surround with left rear surround and Y on the right to feed left and right to the sub? Is it possible this setup could damage my receiver?

 

[ThomasW]

The choice of speaker size determines the low frequency cutoff point of the effects speakers.

No DON'T use a "Y", the rear outputs are not designed to be summed.

If you want a rear sub just run a "Y" off the front sub output.

 

[Selden Ball]

Dave,
When adding a sub to augment your rear speakers, set them to be "large". Then a crossover network can be used to direct the frequencies to the appropriate speakers.
You'll have to do some shopping to find the right sub. Just any model won't have the features you need. I'll leave it to others to recommend specific brands and models: this is long enough already
Some subs include the connections necessary for adding them to a pair of existing speakers. Those designs include both left and right audio inputs, either line-level RCAs or speaker-level binding posts or both. They also include L&R outputs which are intended to feed either an amp or your speakers. People argue over which (line level or speaker level) works best.
Most of these subs also include an adjustable crossover network so that the low frequencies go to the sub and only the higher frequencies are passed on to the other speakers. Some include just the low-pass filter, augmenting the bass of the other speakers. Some subs depend on the use of an external crossover network to direct the frequencies appropriately.
Don't forget that with multiple sources of low frequencies in a rectangular room, you will also have to compensate for the interference patterns they'll generate. The dimensions of your room are the same as the wavelengths of some low frequencies. This causes peaks and nulls: places in the room where certain low frequencies add together and are very loud, others where they cancel. The pattern is more complicated as you add more low frequency sources.
I hope this helps a little.