AVS › AVS Forum › Audio › Subwoofers, Bass, and Transducers › Help with sub integration
New Posts  All Forums:Forum Nav:

Help with sub integration

post #1 of 16
4/18/12 at 8:54am
Thread Starter 
I am trying to integrate my subwoofer (SVS SB12-NSD) with my LR towers (Monitor Audio GX200). This is for music.

I have been running a lot of tests, and changed the L/R and sub locations a number of times. Best compromise I found so far for the sub xover is around 100-110Hz, phase to -180.

I don't believe my receiver (Yamaha RX-A1000) equalizes the sub signal, so xover frequency / phase it is.

No matter what I change, REW shows a couple of deep 'valleys'. The first one is centred around 50Hz, and a much narrower one around 150Hz.

The room is about 15x18ft, 8ft high, but it's open at both ends. At this stage I don't have any sound treatment in place, except for a lot of furniture.



A few questions... Would adding a second sub help filling these gaps? How high would you safely push the sub xover? Does the sub need to be facing the listening point? Would you trust REW of YPAO when it come to the sub gain? I am asking because there seems to be quite a difference of opinions between the two.
Reply
Reply

AVS Top Picks

post #2 of 16
4/19/12 at 7:59am
Thread Starter 
Anyone?
Reply
Reply
post #3 of 16
4/19/12 at 8:31am
Have you tried crossing them over at 60 or 70Hz not sure why you are crossing them over so high bass above 80Hz starts to have localization
What is it exactly that sounds off to you?
Have you tried a different seat for your test the 50Hz dip may get better or it could be the room ?
Need more info room layout, where are you setting and how are your mains relative to your seat?
Reply
Reply
post #4 of 16
4/19/12 at 9:54am
Thread Starter 
Quote:
Originally Posted by oztech View Post

Have you tried crossing them over at 60 or 70Hz not sure why you are crossing them over so high bass above 80Hz starts to have localization

Hi, thanks for replying. I have tried many combinations of sub location, and crossover. At 60 and 80 Hz the 50 Hz null is even more pronounced. Same happens at 40 Hz crossover.

Quote:
What is it exactly that sounds off to you?

Bass sounds a little 'boomy' if I set the xover anywhere under 90-100Hz. Other than than, I was hoping that REW, along with the experience of the people in this forum, would be a better judge of what is off than my ears.

If I just use the towers without the sub, bass is less boomy, but then I miss the LF extension.

Quote:
Have you tried a different seat for your test the 50Hz dip may get better or it could be the room ?

I don't have a lot of room to play with the seating unfortunately. I could turn the whole setup 90 degrees (set the TV against the wall where the bookshelf is now), but there are some drawbacks I can see with that.

Quote:
Need more info room layout, where are you setting and how are your mains relative to your seat?

I'm attaching a sketch, hope it's legible.



I am sure the opening on the left side does not help. I was thinking maybe a second sub (placed on the other side) could help filling some of the gap. I that a silly notion?
Reply
Reply
post #5 of 16
4/19/12 at 10:19am
I would try a wider spead with your towers and toe them in a bit. I would also try the sub in either one of the front corners or the rear corner. Once you try this then set the Xover in the AVR to 80hz and the LPF of LFE to 120hz and either disable the xover on the sub amp or turn it to the highest possible value, I would then flip between 0 and 180 degree phasing and see which one is louder and sounds better.
Reply
Reply
post #6 of 16
4/19/12 at 11:42am
Quote:
Originally Posted by flickhtguru View Post

I would try a wider spead with your towers and toe them in a bit. I would also try the sub in either one of the front corners or the rear corner. Once you try this then set the Xover in the AVR to 80hz and the LPF of LFE to 120hz and either disable the xover on the sub amp or turn it to the highest possible value, I would then flip between 0 and 180 degree phasing and see which one is louder and sounds better.

This and try both corners making sure you experiment with 1 to 2 foot increments don't laugh 1 foot out from the corner and 1 foot closer to one wall got rid of a nasty dip in my old Velodyne but it did give me a peak at 35Hz but I used a notch filter in the AVR to tame it.
Reply
Reply
post #7 of 16
4/20/12 at 8:15am
Thread Starter 
Quote:
Originally Posted by flickhtguru View Post

I would try a wider spead with your towers and toe them in a bit. I would also try the sub in either one of the front corners or the rear corner. Once you try this then set the Xover in the AVR to 80hz and the LPF of LFE to 120hz and either disable the xover on the sub amp or turn it to the highest possible value, I would then flip between 0 and 180 degree phasing and see which one is louder and sounds better.

Actually the speakers are already ~15deg toed in, sorry the sketch does not show that. I'll play some more with the positioning of the sub, for instance I never tried using the opposite corner.

I am confused about your next sentence. I understand about the AVR xover frequency, and the sub xover was always set at maximum in all my testing (followed the Yamaha manual). How do I setup the "LPF of LFE", is that another AVR setting?

If it comes down to keeping the xover at 110Hz, are there any drawbacks for the sub's health, or any other implications?
Reply
Reply
post #8 of 16
4/20/12 at 8:19am
Thread Starter 
Quote:
Originally Posted by oztech View Post

This and try both corners making sure you experiment with 1 to 2 foot increments don't laugh 1 foot out from the corner and 1 foot closer to one wall got rid of a nasty dip in my old Velodyne but it did give me a peak at 35Hz but I used a notch filter in the AVR to tame it.

Will do. I don't believe that my RX-A1000 has sub equalization. It's sure one of the things I'll look for in picking my next receiver.
Reply
Reply
post #9 of 16
4/20/12 at 1:34pm
Quote:
Originally Posted by BarracudaDelGato View Post

Actually the speakers are already ~15deg toed in, sorry the sketch does not show that. I'll play some more with the positioning of the sub, for instance I never tried using the opposite corner.

I am confused about your next sentence. I understand about the AVR xover frequency, and the sub xover was always set at maximum in all my testing (followed the Yamaha manual). How do I setup the "LPF of LFE", is that another AVR setting?

If it comes down to keeping the xover at 110Hz, are there any drawbacks for the sub's health, or any other implications?

Ok... Well then play with the Front L&R speading them farther apart or moving them closer together and play with the angle of toe in or toe out or straight on.... Alot of eq freq response has to do with the room itself and the placement of the speakers and subs.

In Onkyo receivers there is a setting calle LPF of LFE (Low Pass Filter of the Low Frequency Effects channel) you want that set to 120hz to ensure that all audio from that .1 channel is being output by the sub, maybe yammy doesn't have a selectable setting.

No there aren't any physical drawbacks to the sub as far as damage or anything like that is concerned with a 110hz xover.
Reply
Reply
post #10 of 16
4/23/12 at 8:15am
Adding a second sub may help but if the second sub fills in at 150 hz, that's a pretty high frequency and it may result in localized bass.

I guess you don't have another receiver to try?
Reply
Reply
post #11 of 16
4/23/12 at 8:30am
Quote:
Originally Posted by BarracudaDelGato View Post

I am trying to integrate my subwoofer (SVS SB12-NSD) with my LR towers (Monitor Audio GX200). This is for music.

I have been running a lot of tests, and changed the L/R and sub locations a number of times. Best compromise I found so far for the sub xover is around 100-110Hz, phase to -180.

I don't believe my receiver (Yamaha RX-A1000) equalizes the sub signal, so xover frequency / phase it is.

No matter what I change, REW shows a couple of deep 'valleys'. The first one is centred around 50Hz, and a much narrower one around 150Hz.

The room is about 15x18ft, 8ft high, but it's open at both ends. At this stage I don't have any sound treatment in place, except for a lot of furniture.



A few questions... Would adding a second sub help filling these gaps? How high would you safely push the sub xover? Does the sub need to be facing the listening point? Would you trust REW of YPAO when it come to the sub gain? I am asking because there seems to be quite a difference of opinions between the two.

It does look like a room issue unfortunately. Seems like the best way to address is multiple subs and/or room treatment. EQ is not gonna help that dip you can't boost through that big a dip. 3-6db is about all the boost you can reasonably apply and your way beyond that.

Since you have REW something you might try:

We are going to emulate multiple subs by using your mains. Lower your crossover point on your mains to their -3db point. Hopefully this will get your crossover closer to the dip. Now, Adjust the phase using the Distance setting for the subwoofer on the AVR. Hopefully the avr allows you to adjust this setting while playing a test tone from REW. Here's how: play a sine wave(low gain) centered at the lowest crossover frequency your mains will support with the signal generator in REW. Adjust the distance setting for the subwoofer in the AVR up and down for the max spl you can get. Caution: Only play the sine wave for a few seconds and give a couple minutes rest in-between they are tough on voice coils.

If the AVR won't pass audio when setting the distance for the sub its waaaay more tedious, so just adjust in 1' increments and measure the spl after each.
Reply
Reply
post #12 of 16
4/23/12 at 10:12am
Thread Starter 
Quote:
Originally Posted by NicksHitachi View Post

It does look like a room issue unfortunately. Seems like the best way to address is multiple subs and/or room treatment. EQ is not gonna help that dip you can't boost through that big a dip. 3-6db is about all the boost you can reasonably apply and your way beyond that.

Since you have REW something you might try:

We are going to emulate multiple subs by using your mains. Lower your crossover point on your mains to their -3db point. Hopefully this will get your crossover closer to the dip. Now, Adjust the phase using the Distance setting for the subwoofer on the AVR. Hopefully the avr allows you to adjust this setting while playing a test tone from REW. Here's how: play a sine wave(low gain) centered at the lowest crossover frequency your mains will support with the signal generator in REW. Adjust the distance setting for the subwoofer in the AVR up and down for the max spl you can get. Caution: Only play the sine wave for a few seconds and give a couple minutes rest in-between they are tough on voice coils.

If the AVR won't pass audio when setting the distance for the sub its waaaay more tedious, so just adjust in 1' increments and measure the spl after each.

I can try that. The gx200's are spec'd at 35Hz, though I think that's mostly marketing talk. They only have a couple of 5.5" woofers... I have a 40Hz crossover point on the Yamaha, it seems like the obvious choice for what you are suggesting. I'll report back, it may take a few days.

If you look at the graph I posted, the R speaker response seems better (the 50Hz dip is less pronounced). I wonder why that is.
Reply
Reply
post #13 of 16
4/23/12 at 10:25am
I would say the Right speaker looks better on the graph because of the room and speaker positioning. The Left speaker is near an opening in a room which could cause that freq to be essentially "lost". Looks like your Right speaker is near a solid corner with no openings which usually yeilds a "bass boost". Also those speakers are rear ported and rear ported speakers are usually more touchy to placement than a sealed, front ported or bottom ported speaker.
Reply
Reply
post #14 of 16
4/23/12 at 11:57am
Quote:
Originally Posted by BarracudaDelGato View Post


I can try that. The gx200's are spec'd at 35Hz, though I think that's mostly marketing talk. They only have a couple of 5.5" woofers... I have a 40Hz crossover point on the Yamaha, it seems like the obvious choice for what you are suggesting. I'll report back, it may take a few days.

If you look at the graph I posted, the R speaker response seems better (the 50Hz dip is less pronounced). I wonder why that is.

Make sure to play sine waves at low volume and for short periods!
Reply
Reply
post #15 of 16
4/23/12 at 1:03pm
Quote:
Originally Posted by oztech View Post

This and try both corners making sure you experiment with 1 to 2 foot increments don't laugh 1 foot out from the corner and 1 foot closer to one wall got rid of a nasty dip in my old Velodyne but it did give me a peak at 35Hz but I used a notch filter in the AVR to tame it.

Moving mine in 6" increments made big changes to REW, at least moving toward and away from the wall.
Reply
Reply
post #16 of 16
5/18/12 at 1:05pm
Thread Starter 
I finally found the time for more testing. REW is great, but time consuming. This is what I came up with (charts are 15-400Hz):

YPAO 'natural' eq. L, R and sub:



YPAO 'natural' L+R (averaged), sub:



It's not bad (the 50Hz dip is basically gone), but I still have some dips (main one around 90Hz) thanks to the opening by the left channel. I think that a second sub (or a new door) are needed in order improve things substantially.
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home

AVS Top Picks

AVS › AVS Forum › Audio › Subwoofers, Bass, and Transducers › Help with sub integration