Subwoofer crossover versus receiver crossover

[ultrafast]

Hi all,

I've recently been upgrading my system a little and with the bewildering set of options I have now I would greatly appreciate some advice.

Until now I had the following setup. Denon AVR 2308Ci receiver hooked up to my Quad 22L front speakers and Polk Audio RTi 8 rear speakers, supplemented with a Hsu VTF-1 sub via the Sub out connection. This setup was great for movies, but for music I always felt that I was not making the best of my front speakers and the bass was a bit boomy. For this reason I just installed an Emotiva XPA-3 amplifier via the Pre-out connections on the Denon for the front speakers. After quite some playing around I discovered that the best sound could be had from putting the Denon on "pure direct" mode, but unfortunately this cut out the sub completely. In the other modes the sound wasn't as crisp and the midrange sounded a tad muted. To fix this I wired in the subwoofer using the speaker level cables and turned on its crossover at about 60Hz and set the receiver to have the front speakers as "large" and disabled the subwoofer output.

This seems like an acceptable compromise so far, but I am wondering how this reacts with the LFE channel on Blu-Ray discs and if the speaker signal suffers any from being passed through the extra stage. If indeed there are drawbacks to this method, what would you recommend instead to make best use of these components?

Thanks so much for your help!

 

[j_garcia]

You don't have to use direct to set your mains to large and still have the sub in the mix. Likely you are getting boom because you have too many speakers that playing down to frequencies that are localizable and conflicting due to locations. If properly crossed over, the sub should handle the majority of the bass, however a VTF-1 seems like it is insufficient of a sub compared to the rest of your speakers.

If you haven't calibrated the system to see if/where you have humps or dips in response, then you can't really set the crossover properly the way you have it configured. Basically, without knowing where your sub overlaps with your mains, you don't know what you are getting. I would use the receiver's crossover with it set as low as possible so that you don't have any overlap bass between the sub and the mains, but it may be that you simply need a better sub to get the most out of your setup.

In this configuration, you don't have an LFE channel; that information is simply sent to the R & L mains AND the sub. Using the receiver's x-over does not preclude you from using Direct mode in certain instances as well, to temporarily set your speakers to large, but you would also need to be playing a multichannel signal that has an LFE channel for the sub to receive signal (such as movies, SACD, DVD-A, etc...). Stereo signals are just that: no LFE.

 

[AVRat]

The 2308 has a 2-channel direct setup that can be configured differently than say full system usage, see pg 28, 29. The unit also should use the sub in "pure direct" mode if the system is configured to do so in general, see the table on pg 61. You didn't say what x-over point you're using but 60hz or 80 hz should work fine.