# Bought a BFD....Now I'm really confused about which placement...Take a look!



## bgilly (Apr 18, 2007)

Ok....I bought a BFD with the hopes of fixings a few peaks. Well it turns out when I fixed them to match where other areas were, I really cut my subs performance down in the major bass happy areas that I love. SO I took some advice and started from scratch and I played around with placement again. I really have 1 spot, and the 2nd can be done but it really screws with my right main speaker placement. If I had a box sub (I have a pc 16-46+ which I bought because I liked the PC and its deep freq response and ease of placement), anyways...If I had a box sub now, it would fit in the right front corner perfect and I could just put the main speaker on top of it...Oh well thats another story! 



So after testing Here are the results:

For the pictures.

Purple Graph is Front corner NO EQ
Red Graph is Front Corner WITH EQ
Yellow Graph is Rear Corner NO EQ
Blue graph is Read Corner WITH EQ


The sub was dialed in to 77db before running each test.

Now the question is....

Do I go with rear....where I gain from 16-21hz, but lose out big (4-5db) from 21hz to 80hz since I had to make so many cuts to get everything down to the 30-40hz level which was lowered nearly 6db because of placement. Here I only made cuts to get it flat.

OR

Do I go with the front, which I lose out 3-4db on the really low stuff Under 21hz, but gain anywhere from 2 to almost 6db across the board from 21hz up just by moving it. Here I made a few cuts here and there from 25-45hz....and I boosted the upper bass (60-80hz) which isn't nearly as hard on a sub as the lower end, so I think I had headroom to boost this without having to worry.


----------



## robbroy (Oct 19, 2006)

Personally, I'd go with the blue (nice mild "house" curve that would respond well to less than reference volumes). I'd try to flatten that hump between 40 and 50 if I could.

-Robb


----------



## bgilly (Apr 18, 2007)

I do see the benefit down low for the blue graph.

But there is a major difference in the 30hz range in favor of the red graph.

Both graphs were done at the same volume and the same calibration. The only difference was the location and the EQ.

That being said there is a major gain in SPL above 20hz for the red vs the blue.....wouldn't that be better for movies? Above 30hz I get almost a 6db gain at the same master volume just buy using different placement.

To get the blue flat I had to dramatically reduce 20-30hz and 40-50hz to get those ranges equal with the 30hz range, which results in overall lower SPL from 25hz up. The one benefit to the blue graph was it was right next to the couch which probably explains the increase in SPL under 25hz. Easier to get higher numbers there when corner loaded next to the couch.


My usual listening level is about -10 to -7 Master volume from 0db reference. It isn't soft by any means


----------



## robbroy (Oct 19, 2006)

bgilly said:


> I do see the benefit down low for the blue graph.
> 
> But there is a major difference in the 30hz range in favor of the red graph.
> 
> Both graphs were done at the same volume and the same calibration. The only difference was the location and the EQ.


There's your problem -- both were NOT done at the same calibration -- both were done at the same *level*. You should find the curve you want, *then* calibrate.

-Robb


----------



## bgilly (Apr 18, 2007)

Ok wait...let me learn here.

So...I kept my MV for the sweeps the same. In both locations I dialed in the subwoofer to 77db before taking the measurements.

So exactly how should I go about doing this differently?

I'm really excited that it is you responding....I've seen your other posts and you really know your stuff!!!

I'm on here, the spot, and Avs...


----------



## robbroy (Oct 19, 2006)

bgilly said:


> Ok wait...let me learn here.
> 
> So...I kept my MV for the sweeps the same. In both locations I dialed in the subwoofer to 77db before taking the measurements.
> 
> ...


You flatter me, sir, but I don't know squat. I just regurgitate what I learn from the likes of Ed Mullen.

You did everything right (as near as I can tell), you just didn't do the last step. Ignore the relative levels between those curves (assuming they're all reasonably flat), pick the *curve* that is best, recalibrate, sit back, and enjoy. Once you recalibrate (assuming you're not pushing the sub beyond its capabilities) you will regain the lost headroom between those two curve you saw.

-Robb


----------



## bgilly (Apr 18, 2007)

Well I went back to the couch placement because I couldn't live with that front corner placement and how it was totally misplacing my front right speaker.

If I only had a box design instead of the PC design....lol

SO here is my new graph...

Before EQ and after EQ......You can see I put in a low end house curve because I really do like the low end stuff :yay:


----------



## OvalNut (Jul 18, 2006)

So .... how does it sound? 


Tim
:drive:
_Posted via Mobile Device_


----------



## bgilly (Apr 18, 2007)

So far so good.

Certain things sound better here

Certain things sounded better up front.

For instance....Pulse and WOTW Both are slightly more impressive in this location because they have such low end bass and since it is right next to the couch you get more SHAKE.

Others like Master and Comm and u-571 sounded better up front because of the increase in 25hz up headroom that I gained with that placement.

One other thing was that the bass SEEMED to blend better (even after adjusting phase in both locations) with the mains when the sub was upfront...but only by a slight margin.

BUT I'm not going with front placement because I didn't like displacing my main that much from the center and other main. Just didn't look, or sound right to me.

So for now the 16-46+ stays in the corner by the couch and will be EQed as shown. This will all change if I can sell it and get a good reasonable amount of $$ for it...>Then I'll just go all out and get the PB-13. Then I'll not only have the best sub SVS offers....but I'll also have a box that will fit in both places without messing up any speaker placements. 

But I won't give this sub away for nothing since it is in perfect shape...it would be like buying a B-Stock really since I have the box and everything else still. So if I can't sell it I'll just use it and be happy for now....and maybe down the road I'll just add a PB-13 and stick it in that front corner and do a lot of work to get it and this sub to work together.

Only time will tell...


----------



## brucek (Apr 11, 2006)

> Before EQ and after EQ......You can see I put in a low end house curve


A couple of points on using REW.

Use the standard graph scaling we've adopted here for subwoofers of:

Vertical axis = 45dB-105dB
Horizontal axis = 15Hz-200Hz.

Show your target line with its house curve, so we can see if you're tracking it correctly.

Measure the sub only without the mains through your receiver with the bass management crossover engaged and calibrate the measurement to 75dB (midpoint of 45-105dB allows +/-30dB swing). Sweep from 0-200Hz.

Find the best overall position for your sub through repeated measurements or RTA, then EQ at that position.

Once EQ'd, add the mains and adjust their level to match or suit and adjust the subs phase control (and perhaps sub distance trim) to obtain the smoothest transition at the crossover.

brucek


----------



## bgilly (Apr 18, 2007)

Brucek....I will run the tests again with your recommendations and repost soon.

Thanks for the advice!


----------



## bgilly (Apr 18, 2007)

This scene particular sounded better up front than sub in back.

You can see just how much of this is centered around 30hz.


I just wonder how much more accurate the PB-13 makes this scene sound. People say it is so lightning quick with its bass that it really makes scenes like this one stand out.

ps...here is my room layout...


----------



## bgilly (Apr 18, 2007)

OK so I redid the graphs using the settings you suggested and here are the results

With SUB ONLY and then with speakers engaged...


----------



## brucek (Apr 11, 2006)

Can't get much better than that................. 

brucek


----------



## bgilly (Apr 18, 2007)

It does look pretty good! :bigsmile: Thanks!

I just wish that front corner placement was possible because that graph could look close to that one, but about 3-4db higher just because of placement.

I'll attempt to sell the PC so I can get a boxed version, but if I can't at least the EQ helped me to get this to point.


----------



## bgilly (Apr 18, 2007)

Update...Sold the PC+.

Ordered the PB-13 in textured black

The box design will work so much better in my set up because now I can fisably use the front right corner and those results should be staggering! Plus now I will have the best subwoofer on earth for the money!!!


----------



## mrsollars (Apr 17, 2008)

any measurements with the pb13ultra???


----------



## bgilly (Apr 18, 2007)

check my AVSFORUM post....or the other post on this board with my impressions


----------

