what specis (4 a sub)do i need to look for if buying new recevior (1 Viewer)

[David D. C.]

if i buy a new reciever what spec tell about what will be sent out to the subwoofer

 

[Selden Ball]

I'm not quite sure what you're asking, but...

I think the crossover frequency is what you need to look at. Modern receivers only have a "line level" subwoofer/LFE output. They have to be used with a powered subwoofer. Wattage isn't a consideration for that output.

The receiver's subwoofer/LFE output can be used to augment speakers that don't have very good low frequency response. Low frequencies below a "crossover frequency" get sent to the subwoofer and frequencies higher than the "crossover frequency" go to the speakers you designate as "small". "Large" speakers get the full range of sound.

Different receiver designs have different crossover frequencies. Some receivers give you a selection. Typical values might be 50, 100 or 120Hz. THX certified receivers crossover at 80Hz. Some speakers require higher crossover frequencies than that. You'll need to check the specs of the speakers you'll be using.

The crossover filter isn't a "brick wall", however. Your speakers should be able to produce some sound down to half the frequency of (that's one octave below) the crossover that you'll be using. THX requires that they be down 6dB (that's 1/4 the sound level) at 40Hz, for example.

Does this help?