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My front speakers have dual 10' woofers and my surround have dual 6.5' woofers. Should i set the reciever to route all the bass to the subwoofer? or set it as to where ,the subwoofer only play the bass from the lfe channel. or the last option, route bass from center and surround to subwoofer? what is the best option?
 

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Fronts set to large, surrounds to small, sub either LFE or plus (plus is LFE and front bass, this will give you bass with sources that are stereo/aren't X.1 encoded)


I would only set the fronts to small if your receiver has a very low x-over point available (like 50hz or so) otherwise you are wasting the potential of your mains.
 

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My mains have dual sealed subs that have textbook roll off below about 45 Hz (-3dB at 40 Hz). My sub is a Rythmik Audio 12" servo sub in a sealed box.


It seemed logical to me to set the mains to large even though the Rythmik is very good in that last octave. However in the room the smoothest and flattest curve with the sub was with the mains set to small.


Repositioning the sub and trying various crossover points brought be back to the large setting. It is not as smooth but to my ear, it sounds a bit more balanced across the seating area, not just the sweet spot.


With almost all two channel orchestral and other acoustic music, setting the mains to large sounds best.



So my suggestion is that you try several combinations and listen to each for an extended period. Then take what sounds best.


Of course you can do measurements which if nothing else help to train the ear, but in the end it's all in your head.
 

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Quote:
Originally Posted by trekguy /forum/post/0


My mains have dual sealed subs that have textbook roll off below about 45 Hz (-3dB at 40 Hz). My sub is a Rythmik Audio 12" servo sub in a sealed box.


It seemed logical to me to set the mains to large even though the Rythmik is very good in that last octave. However in the room the smoothest and flattest curve with the sub was with the mains set to small.


Repositioning the sub and trying various crossover points brought be back to the large setting. It is not as smooth but to my ear, it sounds a bit more balanced across the seating area, not just the sweet spot.


With almost all two channel orchestral and other acoustic music, setting the mains to large sounds best.



So my suggestion is that you try several combinations and listen to each for an extended period. Then take what sounds best.


Of course you can do measurements which if nothing else help to train the ear, but in the end it's all in your head.

I have seen your measurement results in another post. There seems to be a small dip at the xover frequency and I am wondering if you have tried using delay time adjustment on the receiver menu and if that would help at all. Delay time adjustment has similar effect as the phase adjustment control. A lot of times, the dip is caused by a phase misalignment between the front speakers and sub at the xover frequency. By putting the subwoofer distance a couple of feet farther (closer) than the physical distance would put a phase lead (lag) on the sub and it may help to phase align the two.


Brian

Rythmik Audio
 

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Brian-


Thank you. As it happens I saw your earlier post about this and two days ago I moved the sub forward about 18" and re-balanced the trim. I think I hear a change, but have not measured yet, nor have I tried changing any other settings.


Clearly I need to set aside some time to explore differernt settings and take measurements. Who knew that subwoofer setup could turn into such a challenge?


I have been thinking about a second sub in hope of a better curve across the seating area, but I will try more placement and settings options first.
 

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Quote:
Originally Posted by Volenti /forum/post/0


Fronts set to large, surrounds to small, sub either LFE or plus (plus is LFE and front bass, this will give you bass with sources that are stereo/aren't X.1 encoded)


I would only set the fronts to small if your receiver has a very low x-over point available (like 50hz or so) otherwise you are wasting the potential of your mains.

Can you explain a bit more on how LFE plus works, in particular how the stereo bass is sent to sub? Here is what I can see as the problem. Normally, when we set the speaker to small, there are Linkwitz Riley filters on both sub and front speakers (2nd order on front and 4th order on sub). The L-R filter mandates a 4th order on both sides of the xover, and the reason it uses only 2nd on front is it "assumes" there is a naturnal 2nd order roll-off on the front with corner frequency "close" to the xover frequency (vented box violate this rule). The reason why we use L-R 4th order is it improves phase alignment at the xover point. Now if there is no filtering on the front speaker, we need 1) a 6th roll-off on the sub to achieve similar phase alignment as L-R filter, 2) as there is no filtering on the front, there is no certainty on the actual roll-off frequency of front speakers, the xover frequency on the sub needs to be adjustable as well, and 3) to ensure smooth integration, there needs to be another phase adjustment on the sub, other than the delay time control (because the delay time control is already used by the LFE signal to control it is relative timing respect to other channels).


Brian


Rythmik Audio
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by Rythmik /forum/post/0


I have seen your measurement results in another post. There seems to be a small dip at the xover frequency and I am wondering if you have tried using delay time adjustment on the receiver menu and if that would help at all. Delay time adjustment has similar effect as the phase adjustment control. A lot of times, the dip is caused by a phase misalignment between the front speakers and sub at the xover frequency. By putting the subwoofer distance a couple of feet farther (closer) than the physical distance would put a phase lead (lag) on the sub and it may help to phase align the two.


Brian

Rythmik Audio

ya i measure everything with a measuring tape and i've set it in the receiver. right now the sub is set to play all bass from all channel with a xover at 80hz. i just found out that the best phase in my room is 180 instead of 0. but i think i still get dips(i think thats what you call it). around 40-50hz the subwoofer gets reallly loud to the point things on the wall start rattling.60hz range still barely noticeable. this is testing with the avia lfe bass sweep.
 

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Quote:
Originally Posted by Rythmik /forum/post/0


Now if there is no filtering on the front speaker, we need 1) a 6th roll-off on the sub to achieve similar phase alignment as L-R filter, 2) as there is no filtering on the front, there is no certainty on the actual roll-off frequency of front speakers, the xover frequency on the sub needs to be adjustable as well, and 3) to ensure smooth integration, there needs to be another phase adjustment on the sub, other than the delay time control (because the delay time control is already used by the LFE signal to control it is relative timing respect to other channels).


Brian


Rythmik Audio

Regarding 1), I use the Subwoofer amplifier LP filter (adjustable) in addition to the receiver's filter (also adjustable on my specific receiver). This approximates a 6th order filter.


Regarding 2), you can measure the FR of the front speakers with certainty. You would be surprised how little bass is cut to the mains with the small speaker settings.


Regarding 3), the LFE is not controlled by distance settings. Total combined bass that is sent to the subwoofer is controlled by the subwoofer distance setting. You only need a second phase control if you use dual subwoofers and you need to adjust the relative phase of both subwoofers so you get a phase match.
 
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