db slope

[cheglie]

When in the crossover settings on my UMC-200 I notice there are two slope options of 12db or 24db.  All speakers are set to 12 db except the sub which is set at 24db.  Question is, when would one set the subwoofer to 24db vs 12db?  I leave mine at 24db because that is the default, but I don't understand why?  I started wondering if I could benefit from this mysterious 12db setting?

[aud]

You want to leave it at 24dB, as you're doing. Greatly simplified reason for doing this, is the fact that you want to get the higher frequencies out of the subwoofer 's frequency range much more aggressively because of distortion and localization problems, of that subwoofer.

Slope is dB per octave.

[Gary Cook]

What aud said, plus it depends on how close to the upper limit of the sub woofers effective frequency range you haves the cross over set. If you have the cross over set close to the upper limit of the sub woofers frequency range then you would want to have a faster slope (i.e. 24 db). But conversely, if you have the cross over set a long way below the upper limit of the sub woofers frequency range then you could have a slower slope (i.e. 12 db).

There's no right or wrong, it's very much dependant on the hardware, what other settings you have selected and a large dose of personal preference.


Cheers
Gary

[aud]

Thanks, Gary.

[Chuck Elliot]

Keep in mind that this is dependent of a number of things.

One is what are the mains doing at the desired crossover frequency?

If the main speaker's natural roll-off is starting to come into play, then the new roll-off will be greater than the 12dB set on the UMC-200 and a 24dB on the sub MAY match better.

[cheglie]

Jun 27, 2014 18:24:57 GMT -5 Gary Cook said:

What aud said, plus it depends on how close to the upper limit of the sub woofers effective frequency range you haves the cross over set. If you have the cross over set close to the upper limit of the sub woofers frequency range then you would want to have a faster slope (i.e. 24 db). But conversely, if you have the cross over set a long way below the upper limit of the sub woofers frequency range then you could have a slower slope (i.e. 12 db).

There's no right or wrong, it's very much dependant on the hardware, what other settings you have selected and a large dose of personal preference.


Cheers
Gary

I set the crossover for the mains at 70 and the center and surrounds at 80.  You can see my speaker set-up in my profile.

[Gary Cook]

Jun 29, 2014 19:42:30 GMT -5 cheglie said:

Jun 27, 2014 18:24:57 GMT -5 Gary Cook said:

What aud said, plus it depends on how close to the upper limit of the sub woofers effective frequency range you haves the cross over set. If you have the cross over set close to the upper limit of the sub woofers frequency range then you would want to have a faster slope (i.e. 24 db). But conversely, if you have the cross over set a long way below the upper limit of the sub woofers frequency range then you could have a slower slope (i.e. 12 db).

There's no right or wrong, it's very much dependant on the hardware, what other settings you have selected and a large dose of personal preference

I set the crossover for the mains at 70 and the center and surrounds at 80.  You can see my speaker set-up in my profile.

Some comments, not in any particular order;
* There is some logic in having the L, C & R plus surrounds cross overs set the same, plus I prefer the resulting sound. Give it a try.
* I like to have a cross over not above 80/90 hz as I find the sound becomes directional above that frequency.
* The Power Sound Audio XV15se has a -3db point at 200 hz, so plenty of scope for it to have a 12 db slope.
* Focal Chorus 726V have a -3db point at 49 hz. Not so much slope room there (to 80 hz).
* Personally I'd go for an common 80 hz cross over with a 24 db slope. Then have a play from there.


Cheers
Gary

[cheglie]

Thank you for the replies.

I set crossover for the mains to 80hz in the beggining, I typically use this as my starting point.  Actually with my past sub I was using, a Boston Acoustics 10", it worked out quite well.  When I changed to the PSA it seemed like it was easier to locate the sub's location.  I place my sub "near-field" next to sofa, close to a corner (my front wall has a large window that seems to rob the bass when the sub is placed close).  Anyway, by lowering the crossover to 70hz I felt it helped to make the sub a bit more invisible.  I also moved my mains closer to the front wall to get more bass out of them and this seemed to help decrease localization of the sub as well.  The PSA definately makes it's presence known!  Sometimes I wonder if it is more a feeling (vibration) from the sub rather than sound that increases "localization"?

Slope will stay at 24db.  When I try 12db the difference is very small and quite frankly both sound great!