# BFD eq'd the Sub need opinions, suggestions & comments.



## porksoda (Feb 25, 2010)

Hiya,

I was waiting for the bfd to arrive which it did today and i thought its my official post so i can ask for some opinions. Thanks to everyone who already helped me with some questions and answers in the REW section.

I have rew setup and i am fairly comfortable using it... today I added the BFD to my system as i had a nasty peak at 25hz or so. I was xovering at 60hz which i was not wanting to do as i wanted the sub to handle most of the bass. So i changed the xover to 80hz and used that as my xover.

Today i tried the sub at about a dozen locations took readings and eq'd to see if i can get a better spot... i have one of those worst square rooms. 25 x 25 x 9-10ish.

After all the moving around with the help of my dolly and what a workout... i found the best place for my sub which happened to be the spot i had previously picked.

On to the meat n veg...

I fired up rew and ran my sweep with peq and eq off.

1/3 Smoothing applied.









I had spent hours and hours reading guides written by various people here and i found bfd usage to be piece of pie. I was not only able to fire it up and setup up few filters but also familiarized myself with it thanks to the guide posted/listed here.

I let rew at 1/3 smoothing find the peaks and apply the filters ( i did tweak them a bit and below is the curve i got)

1/3 Smoothing applied.










I tried my usual suspects for bass and i found them to be not as good as the graph suggested and while i tested them. I realised i had the rs in the location on where i sit "middle" of seat instead of "edge" of seat where i was sitting and very happy with the results... i ran rew from that location and found this:

1/3 Smoothing applied.










I cannot really move the sofa so the best seat in the house is where the edge of the seat is.

I ended up creating two presets one with a bit of emphasize on 25hz above my target and one to balance it out.

1/3 Smoothing applied. Preset 1










1/3 Smoothing applied. Preset 2









Any comments and suggestions on perhaps how to improve any of this or this is as good as it gets... from all the listening i have done i am happy the huge 25hz and 43hz dips are gone and make the bass a bit more defined... i do prefer the preset 1 as it gives same few more db's emphasize in the middle of my seat. Preset 2 for movies/blu ray.

Another thing i must note is for my blu ray watching i have set it so its always -10db as the movies are always hot with the lfe.. i ran through few scenes in hurt locker and seemed to be acceptable.

I cannot push the sub to its limits as i am in a condo and i have to worry about negihbours even though they don't care for us.

thanks in advance.


----------



## Nuance (Nov 2, 2008)

Personally, I'd be worried about those suckouts at 58 and 95Hz; they are quite large and wide.

When you were trying different subwoofer locations, did you find one that had no large valley's (like in the graphs above)? If so, perhaps using that location would have been best (better to find a location with a lot of peaks rather than valleys, because you can pull those peaks down no prob). Also, have you messed with phase? One of the suckouts is right at the crossover, so perhaps changing the phase or setting a higher crossover (80Hz) would get rid of that dip.

The huge dip after the crossover might also be remedied with phase/a higher crossover. It could also be due to a room mode or speaker positioning.


----------



## porksoda (Feb 25, 2010)

Nuance said:


> Personally, I'd be worried about those suckouts at 58 and 95Hz; they are quite large and wide.
> 
> When you were trying different subwoofer locations, did you find one that had no large valley's (like in the graphs above)? If so, perhaps using that location would have been best (better to find a location with a lot of peaks rather than valleys, because you can pull those peaks down no prob). Also, have you messed with phase? One of the suckouts is right at the crossover, so perhaps changing the phase or setting a higher crossover (80Hz) would get rid of that dip.
> 
> The huge dip after the crossover might also be remedied with phase/a higher crossover. It could also be due to a room mode or speaker positioning.


Sorry... I guess i forgot to write down on the first post that the xover is 80hz it was 60hz before i did the bfd.

I think phase maybe an issue for sure... what is the best way to set phase... i had used the delay on the avr to set phase per se.

As for the nulls they did exist in most locations... i am limited for the sub location I am thinking it maybe room modes? Also the edge of seating vs middle makes a difference makes me think i am sitting very close to a null? I cannot really move the sofa sub is all i can move.


----------



## mdrake (Jan 31, 2008)

What are the dimensions of the room? 

Matt


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

porksoda said:


> After all the moving around with the help of my dolly and what a workout...


Next time park the sub at your listening position and take readings with the mic in the various proposed sub locations. Much easier in the back, gets the same results. :T

For starters, your graphs have some issues. For one, it looks like you’re taking full-range measurements with both the sub and the main speakers. There is no evidence of that 80 Hz sub crossover you mentioned.

Second, it’s best not to use any smoothing for subwoofer graphs.

Third, under the “Targe Settings” button at the left side of the REW screen, change the speaker type from “Full Range” to “Subwoofer,” and select the appropriate crossover frequency and slope.

After that, take some new readings. It may be that phase issues between the sub and mains are the source of the depressions you’re seeing at 58 and 95 Hz. You can deal with them later, once the sub itself is lined out and equalized. As Nuance noted, see if you can find a better sub location, if that option is available, one where the dips and peaks are not as severe. As it is, you have at least a 20 dB spread between the worst peaks and depressions; that’s pushing it for what can be reasonably equalized. Your sub will have to have some serious headroom on tap if equalization that severe is required.

Regards,
Wayne


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

mdrake said:


> What are the dimensions of the room?
> 
> Matt





porksoda said:


> Today i tried the sub at about a dozen locations took readings and eq'd to see if i can get a better spot... *i have one of those worst square rooms. 25 x 25 x 9-10ish.*



Regards,
Wayne


----------



## porksoda (Feb 25, 2010)

Nuance said:


> Personally, I'd be worried about those suckouts at 58 and 95Hz; they are quite large and wide.
> 
> When you were trying different subwoofer locations, did you find one that had no large valley's (like in the graphs above)? If so, perhaps using that location would have been best (better to find a location with a lot of peaks rather than valleys, because you can pull those peaks down no prob). Also, have you messed with phase? One of the suckouts is right at the crossover, so perhaps changing the phase or setting a higher crossover (80Hz) would get rid of that dip.
> 
> The huge dip after the crossover might also be remedied with phase/a higher crossover. It could also be due to a room mode or speaker positioning.


Hiya... this time around i did rew charts at each location and i am posting them below... i think the best one is behind the loveseat where there are no significant dips. Suggestions on location also i think would be helpful before i eq.

RS meter set to low... main speakers disabled sub on 80hz xover rew sweep ran 1M length.



Wayne A. Pflughaupt said:


> Next time park the sub at your listening position and take readings with the mic in the various proposed sub locations. Much easier in the back, gets the same results. :T
> 
> For starters, your graphs have some issues. For one, it looks like you’re taking full-range measurements with both the sub and the main speakers. There is no evidence of that 80 Hz sub crossover you mentioned.
> 
> ...


Wayne i had tried the crawl method but i did it with spl a while ago and i found two spots best for the positioning and one was the initial position and another is behind the loveseat which i think is probably better as it has no significant dips... suggestions on location please.


Charts: (no smoothing and standard axis)
Please let me know if waterfall or other type of charts are needed. Just by looking at the waterfall here i see the behind the loveseat time does not go as far as the initial position one... i wonder if that is the overhang and ringing for that location?

Initial Placement










Sofa Side Placement










Behind Love Seat Bottom Edge Placement










Behind Love Seat Middle Placement










Behind Love Seat Top Edge Placement


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Yeah, the behind-love seat looks best but quite honestly they’re all pretty bad. Plus I just hate having the sub behind the seating and near-field on top of that. Is there a viable corner at the front of the room you could try?

Also, what sub are you using?

Regards,
Wayne


----------



## porksoda (Feb 25, 2010)

Wayne A. Pflughaupt said:


> Yeah, the behind-love seat looks best but quite honestly they’re all pretty bad. Plus I just hate having the sub behind the seating and near-field on top of that. Is there a viable corner at the front of the room you could try?
> 
> Also, what sub are you using?
> 
> ...


Wayne i Agree... here is my room to give you an idea and perhaps maybe you can suggest a location.
I am using the rythmik f12 w peq2.

The wall behind the loveseat is all windows... not floor to ceiling but 50% of the height is windows.


----------



## glaufman (Nov 25, 2007)

So... not only do you have a mostly square room, which as you stated earlier is naturally an issue, but you're sitting almost dead center in it, magnifying many of the modal influences. The ~25Hz, ~48Hz, ~72Hz issues you see in your graphs are all fundamental/harmonic of those room dimensions. That's why they show up in almost every plot you show. 
In an ideal world, the best thing you could do for your response would be to move the listening position(s). Using this room setup, even if you placed the mic 8'10.5" from the TV wall, I bet you'd see a drastic improvement.


----------



## porksoda (Feb 25, 2010)

glaufman said:


> So... not only do you have a mostly square room, which as you stated earlier is naturally an issue, but you're sitting almost dead center in it, magnifying many of the modal influences. The ~25Hz, ~48Hz, ~72Hz issues you see in your graphs are all fundamental/harmonic of those room dimensions. That's why they show up in almost every plot you show.
> In an ideal world, the best thing you could do for your response would be to move the listening position(s). Using this room setup, even if you placed the mic 8'10.5" from the TV wall, I bet you'd see a drastic improvement.


yes! but the corner of the sofa seat is at 8'4" and the back at 10'. So i probably sit at around (ear level) 9'2"ish i think... I changed the room map up there to reflect distances and the new location of the sub... i did some calibrating and i got this:


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Did you ever try a front corner?

Regards,
Wayne


----------



## porksoda (Feb 25, 2010)

Wayne A. Pflughaupt said:


> Did you ever try a front corner?
> 
> Regards,
> Wayne


Yup... got this:










I have put it just below the loveseat and was able to somewhat flat the curve and then later did your housecurve / hard knee.

Sounds decent except the issue of a vast area for eq.

How do you guys recommend i avg out or eq for a vast area... as you can see from my room i have the middle seat where i usually sit but others some get a lot more bass than i do with lots of peaks.

Should i take 6 measurements (from each seat) and then tame the peaks or how is this usually recommended?


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

> Yup... got this:


Wow, looks just like the others. Can’t say I’ve ever seen a room where so many different positions got such similar measurements. :huh:




> How do you guys recommend i avg out or eq for a vast area... as you can see from my room i have the middle seat where i usually sit but others some get a lot more bass than i do with lots of peaks.


Most people just EQ for the sweet spot and leave it at that. Any equalizing for an averaged measurement is going to compromise response at the sweet spot. 

Still, getting similar results at so many different locations you might have more luck with an averaging exercise than most. I’d take a reading at each location on the sofa facing the screen where someone would sit, and average those. I wouldn’t worry much about response at the “cheap seats.” Movie bass is more about “boom” than anything else, so clinical accuracy is not required for every seat in the house. 

Regards,
Wayne


----------



## porksoda (Feb 25, 2010)

Wayne A. Pflughaupt said:


> Wow, looks just like the others. Can’t say I’ve ever seen a room where so many different positions got such similar measurements. :huh:
> 
> 
> Most people just EQ for the sweet spot and leave it at that. Any equalizing for an averaged measurement is going to compromise response at the sweet spot.
> ...


thanks wayne... your hard knee "white papers" as i like to call them has been very beneficial and answered many of my questions... I do like the upper thump from 0-30hz and then a quick roll off... which was what i was getting initially a huge peak at 25ish hz which made the sub sound very nice.

I also got in a sub 12 from paradigm and a svs eq and i find the svs eq does not eq as well or effectively as the bfd does as its manual and you can give it more parameters.

In any case i think svs maybe for some who are not technically inclined and want the click it and forget it type of deal.

I have spent hours after hours on the bfd/rew combo just playing around but i have plethora of wires tripod and 100s of charts...

either way REW is excellent software and thanks to the creator...

I think today i will try the avg response and put it as a preset and forget about it then i can always dial it in for better overall response than having just my sweet spot. I love the presets on the bfd.


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

porksoda said:


> I also got in a sub 12 from paradigm and a svs eq and i find the svs eq does not eq as well or effectively as the bfd does as its manual and you can give it more parameters.
> 
> In any case i think svs maybe for some who are not technically inclined and want the click it and forget it type of deal.


Correct, and IIR they advertise it as such...




> I think today i will try the avg response and put it as a preset and forget about it then i can always dial it in for better overall response than having just my sweet spot. I love the presets on the bfd.


Yup, they are definitely handy. :T

Regards,
Wayne


----------



## porksoda (Feb 25, 2010)

So here are my hard knee curves as of today. Hopefully this will be the last of my presets...

I may do another preset with "inverse" hard knee for those movies on tv with extra boosted lfe.

Before: (using bfd to set a preset with 0 active filters)










Hardknee with Sub only:










Hardknee with Sub n Mains:










Waterfall:


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Looks good. :T How does it sound?

Regards,
Wayne


----------



## porksoda (Feb 25, 2010)

Wayne A. Pflughaupt said:


> Looks good. :T How does it sound?
> 
> Regards,
> Wayne


Sounds pretty good. It's my final preset for daytime.. night time i use the 75db hard knee which takes the bass down a bit...

both sound excellent... i was able to get one of my two peaks down with the peq but with the bfd it adds a new dimension... its like old school eq presets classic, pop, flat etc etc... i basically have a flat.. hard knee and 75 db hard knee.

excellent combo. I tried the svs one again in my system and it does not do as good of a job in so many words...


----------

