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AVR300 sub xover frequency and spkr sizes

Discussion in 'Arcam Owners' Forum' started by Remboy, Jan 9, 2005.

  1. Remboy

    Remboy
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    Hi

    Have just purchased a sub for my system and wonder if anyone could clear up some confusuion as to how the combination of settings affects the output from the AVR300. I am finding setting up the sub far harder than any other part of my surround sound set up. I will still be using stereo direct for music so the sub will be for movies only. I am aiming for bass "extension" not more bass, providing a seamless improvement to my pre sub set up.

    I currently have fronts, rears and centre set to Large since a previous post by Andy Dutton suggested leaving these 5 speakers set to Large would maximise sound quality (as opposed to bass loudness). Am I right in believeing that with these settings ONLY the LFE signal will be sent to the sub, i.e. no bass redirection from the other 5 speakers regardless of where the sub xover freqency is set? In which case the setting of the sub xover frequency will have no effect on main 5 speakers, only the point at which the sub comes in?

    I saw in another thread that the specs for Dolby state that only frequencies up to 120Hz are included in LFE so if the sub xover frequency is set below 120Hz, any information in the LFE channel between the sub xover frequency and 120Hz would be "lost"?

    If I am right about the above (which is quite probably not the case!) would the optimum set up be Large setting for all 5 speakers and 120Hz setting for sub xover frequency?

    Thanks for any help - the number of possible combinations of settings on sub and AVR300 is a bit bewildering without advice on a decent starting point to begin experimenting from!
     
  2. RaceTripper

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    If you are using the Sub only for movies, then set xover to bypass and use the AVR300 crossover setting. Setting the AVR xover to 80Hz is a good starting point. You should not use both xovers to manage bass.

    Any speakers set to large will not be redirected to the Sub. If you bypass the sub's xover (as per above) it will correctly handle all the LFE sent to it without filtering.

    Whether or not you set any speakers to small for sub redirection depends on how well the speakers handle lower bass and the quality of the sub. If your speakers have good bass response, setting them to large is a good starting point. Otherwise, set them to small to start.

    If you allow the sub to handle the low bass for speakers, the AVR300 amps for those channels won't have to work as hard and will give you some more room for handling the dynamics of movie audio. OTOH: setting them to large may sound better.

    The best bet is to try different scenarios and see what sounds and works best for you. But the most important part is to get the sub correctly positioned, and set the gain and phase of the sub for the best response and integration with your other speakers. This is the hard part. Then experiment with using or not using bass redirection for the speakers.

    As an example...
    Previously I had a set of Dynaudio speakers with a Dynaudio Sub30A, and set them all to large. They range in lower bass reponse betwen 28Hz (for the mains) to 45Hz (for center/surr). I recently upgraded my sub to the Dynaudio Sub500 which is vastly better. I have now set my speakers to small and set the AVR300 xover to 60Hz so that the speakers do now get redirected. This seems to work well for my setup where with the previous sub it didn't so much. But in my case the Sub500 integrates extremely well with my 7 speakers.

    But mileage varies, so you just have to try it for yourself. Salt and pepper to taste...
     
  3. Remboy

    Remboy
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    Thanks for the reply Dean

    I have the xover on the sub bypassed already. I'll set the xover on AVR300 to 80Hz and speakers are all set to large (all 5 hanndle frequencies down to about 40Hz). Does this mean that information below 80Hz will not be redirected from the 5 channels to the sub? The sub only gets LFE, right?

    What about LFE information which is above 80Hz - will this be sent to the fronts or simply filtered away and "lost"?

    Very grateful for your help as this is rather confusing and I know from previous threads that you've had to go through these hoops as well! Cheers.
     
  4. RaceTripper

    RaceTripper
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    If your speakers are set to large, all freqs are sent to them and none to the sub, which then only gets the LFE channel. Redirection only happens for speakers set to small.

    The xover setting in the AVR300 does not apply to the LFE channel (only speakers set to small), so the Sub always gets the entire LFE channel without rolloff, regardless of the AVR xover setting, as long as the sub's xover is bypassed. So if all speakers are set to large, the AVR xover setting is irrelevant since nothing is getting filtered -- it's only for speaker redirection.
     
  5. Remboy

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    That's great, I think I finally understand! Thanks for your help Dean..will go play!
     

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