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Subwoofer connection

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music_lover

Hi-

I have a Denon AVR-587 receiver and a Velodyne Vx-10 subwoofer. A few questions:

1. Which is better? Speaker level input of line level input?
2. If I have to connect using the "sub output" in the receiver, I see two inputs in the the sub-woofer (L and R (mono)). Wo which one should I be connecting the receiver output. (I don't find a seperate LFIN input in the sub).
3. What does the pahse 0 and 180 mean in the subwoofer?
4. Can I use a plain RCA cable, or should I buy the special sub-woofer cable?

Thanks!!

Follow Ups:

RE: Subwoofer connection - David Aiken 22:43:56 11/23/07 (2)
I've got a Denon AVR, the 2807, but I'm not familiar with your model, and I have no experience with Velodynes. My sub it a REL. However, given all that, what I'd say is:

1- If you're using an AVR and you are going to use it for movies also, I'd go for a digital connection between the DVD player and receiver in order to preserve the LFE channel in soundtracks and then I'd use the low level sub out from receiver to the sub. If the sub is being used in a 2 channel music only system, then I'd try both line and speaker level connections and go with which sounds best to you. For movie use, even if it's only a 2 channel setup, using a digital connection from the player to the receiver will preserve the LFE channel (the .1 channel) which will be stripped from the soundtrack if you use a 2 channel analog connection to the receiver. The only way to keep that LFE channel all the way through to the sub is to use the line level sub out on the receiver. You will still get a signal there if you use analog connections from the player to the receiver but some info will have been thrown away by the player in its downmix to stereo output so preserving the LFE channel requires the combination of digital output from player to receiver and sub channel out from receiver to sub. Make sure the player outputs 5.1 channel surround sound to the receiver and let the receiver handle the downmix if you're using fewer channels.

2-I'm guessing here but go with the R (mono). You're using a mono connection from the receiver and so you're going to want the sub to handle a mono signal. It sounds as if the sub 'assumes' it's getting stereo signals if you use the L connection. Read the manual if you've got one but that's what it looks like to me.

3- The phase setting helps you get the best integration with your main speakers. 0 and 180 degrees is a pretty coarse adjustment but it does work and it's also all I've got on my sub. If your receiver has an auto setup function and it calculates and sets the speaker distances in order to match the arrival times from each speaker, you won't need to worry about this on the sub. Set it to 0 degrees, run setup, and forget. If you have to do things manually, read the manual in order to get the best results.

4- You can use a plain interconnect. Sub cables come in longer lengths which can be handy if your sub is some distance from your receiver, and a longer cable will give you more flexibility on sub placement. Sub cables may be slightly better shielded too. I don't know if they have any other advantages.

David Aiken
- RE: Subwoofer connection - music_lover 09:38:34 11/25/07 (1)
  Thanks much. BTW, is it necessary that the sub should always be placed between the front left and right speakers?
  
  Thanks!
  - RE: Subwoofer connection - David Aiken 10:52:50 11/25/07 (0)
    No, but sub placement can be messy since differences in listening distance between the sub and speakers can affect arrival time and phase (many AV receivers compensate for this) and the sub's own internal circuitry can impose a further time lag (receivers which 'measure' the distance based on differences in arrival times of test tones from each speaker also compensate for this automatically since the sub delays the test tone also).
    
    The other issue is crossover frequency. The higher up mains cross over to subs, the more likely it is that you will perceive the sub as another source. There is evidence that crossover at 80 hz is OK on this point and this is a recommended crossover point for HT setups but lower is better/safer.
    
    In theory, if the crossover point is low enough so that localisation is not a problem and arrival time and phase are compensated for, it shouldn't matter where the sub is placed. You would then place the sub where it worked best in the room and there's been a huge amount written on that. A good place to start is always the particular manufacturer's recommendations.
    
    David Aiken

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