# I need a little help from the guru's vast knowledge.



## TJHUB (Apr 7, 2008)

I've been using REW with my BFD (1124P) for many weeks now. I've learned a lot from this site and I have been very successful up until this point. My problem is that I got a new sub...

Here's a quick pic of the new sub (it's the one in the middle):










Before anyone asks: no, I don't have both subs hooked up in that pic. I only use the Ultra. I had the PC+ sitting there for reference pics. I'm selling the PC+.

The Ultra is just a bit too big for my preferred location, so I was forced to rotate the sub 90 degrees so that the driver faces my entertainment center. Here is a pic of the sub facing forward in its final home with my chair in place:










Here is the un-EQ'd measurement with the sub facing forward:










Here is the un-EQ'd measurement with the sub rotated 90 degrees (driver facing entertainment center):










As you can see, the frequency response is significantly changed (IMO). The only real issue I have is trying to work with the dip from 55-70Hz. I honestly think I hear that dip. Also, when I attempt to EQ the sub for a flat response, neighboring filters cut that area even more.

This brings me to my problem/question: Just how bad is it if I add a filter that boosts 63Hz with a BW of 8 and a gain of 5db? It was the only way I could get this:










I'm no noob at this stuff (well not completely). I rarely use REW's recomendations anymore. I've gotten much better at applying my own filters. My PC+ was EQ'd flat with 2 filters. So long to those days...

Any comments?


----------



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

> My PC+ was EQ'd flat with 2 filters. So long to those days...


I suggest raising the target to 80 dB and trying again. Do that and you could probably take of the 50 Hz and below region with a couple of filters, and above that point with another one. You might want to review my Minimal EQ article.



> Just how bad is it if I add a filter that boosts 63Hz with a BW of 8 and a gain of 5db? It was the only way I could get this:


See here.

Regards,
Wayne


----------



## brucek (Apr 11, 2006)

> As you can see, the frequency response is significantly changed


Hardly enough to even talk about.... 



> The only real issue I have is trying to work with the dip from 55-70Hz.


Again, not enough of a dip to even consider filtering.



> when I attempt to EQ the sub for a flat response, neighbouring filters


As Wayne so correctly alludes to, you are filtering way too much. I can't imagine using any more than three filters for that raw response, and I'd probably use two and then add my mains and see if I needed a third.

The notion that the response has to be like ruler is an error many people make. It's simply not necessary. Let that horse out of the barn and quit holding it back with all those filters.

brucek


----------



## tonyvdb (Sep 5, 2007)

Rotating a sub will hardly make a difference as bass is non directional by moving the sub to another part in the room or even starting with it dead center and then walking around the room to find the best response is a good option. By placing it in the spot where you hear the best response you will then get the best placement for the sub.


----------



## TJHUB (Apr 7, 2008)

Wayne A. Pflughaupt said:


> I suggest raising the target to 80 dB and trying again. Do that and you could probably take of the 50 Hz and below region with a couple of filters, and above that point with another one. You might want to review my Minimal EQ article.
> 
> 
> See here.
> ...


Wayne,

At first I wasn't following you at all. As a matter of fact, I thought you were crazy to tell me to raise my target to 80db. But I get it now. 

I had read, and thought I understood your minimal EQ post, about a month ago. It worked out very well on my PC+ as I went from 5 filters down to 2. I can tell you that I think I just made another leap forward in understanding REW and how to use it. You are no doubt a very wise man. I can't thank you enough!

Now I can't wait to get home to re-EQ my new Ultra! :bigsmile:

Just as an FYI, here was my attempt to EQ my Ultra:


----------



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

brucek said:


> Hardly enough to even talk about....





tonyvdb said:


> Rotating a sub will hardly make a difference as bass is non directional


Yeah, I was thinking about that after making my post, and was coming back to add, "That's not what I'd call a 'significant change' in response - unless it actually _sounds_ different," but you guys beat me to it. 

Regards,
Wayne


----------



## TJHUB (Apr 7, 2008)

All this talk about no change when rotating the sub...

How can you not say that the ~94Hz suck-out is reduced and 100Hz goes up quite a bit? I also lose ~5db in 55Hz-70Hz range compared to ~36Hz. This is not significant? Those seem like big enough numbers to me. 

What am I not getting here? :huh:


----------



## brucek (Apr 11, 2006)

> What am I not getting here?


That moving your meter half a foot will cause the same effect. You haven't really changed the overall sound by much at all with a rotation. It can modify the overall level somewhat, but lay the responses over top each other on the Measured tab and use Trace Offset feature to get a better feel what has actually happened. They're simply not different enough to worry about.

brucek


----------



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

What brucek said. Fortunately, our ears are pretty forgiving; they don't hear the same way a mic "does." As I noted, I doubt you can hear a difference between those two plots. As another example, here's some baseline (before EQ) readings in my room at five different locations (traces offset for easier comparison). As you can see, they look quite different, but I can't tell an audible difference at any of those locations.










Regards,
Wayne


----------



## TJHUB (Apr 7, 2008)

Ok gents. I'm very interested in a little EQ help if anyone would be so kind to walk me through what I *should* try. I moved my sub around a little bit and finalized it's location. I took a measurement and saved the data so I could play with it at work today with your help. 

Here is a graph of my raw measurement:










I think I have the target level in the best spot for EQ'ing. I did get a decent looking graph with 3 filters, but I'm still interested in a little help/advise.

Thanks.


----------



## TJHUB (Apr 7, 2008)

Here is my attempt:










The filter parameters are:

Freq. Gain BW/60
25 -4 -8 24
40 -2 -13 10
63 -6 +10 12

Thoughts?


----------



## TJHUB (Apr 7, 2008)

Here's one I may like better as my mains seem to be a little weak around 80Hz:










Freq. Gain BW/60
(20 +10) -10 31
(40 -2) -16 13
(63 -6) +10 12


----------



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

Your top two graphs (at the opening of the thread) looked better. This one has the 60-70 Hz region much more depressed.

I notice you aren't using a house curve. Any particular reason? A +6 dB house curve, for instance, would require less cutting at the lower frequencies, and at the same time require less boost down at the 63 Hz region (see my house curve article to determine the proper curve for your room).

Also, please uncheck the "Invert Filter Responses" box, so you can see the true action of the filters.

Regards,
Wayne


----------



## TJHUB (Apr 7, 2008)

Wayne A. Pflughaupt said:


> Your top two graphs (at the opening of the thread) looked better. This one has the 60-70 Hz region much more depressed.
> 
> I notice you aren't using a house curve. Any particular reason? A +6 dB house curve, for instance, would require less cutting at the lower frequencies, and at the same time require less boost down at the 63 Hz region (see my house curve article to determine the proper curve for your room).
> 
> ...


Well, the first graph was with the sub facing forward, and the second is with it rotated sideways. My graph from last night isn't all that different. According to some of you, the difference between the first two graphs wasn't worth talking about, so I don't see how my latest graph would qualify any different. I don't understand the change, but I did about 10 measurements before settling on the one I posted.

I unchecked the "Invert Filter Responses" box (repost of the graph):










For some reason, I just like to have a flat curve available. I've tried about 20 house curves with my PC+ and settled on what I call a "4db house curve" that sounded the best. My primary concern is music performance. If music doesn't sound perfect to me, I couldn't care less how movies sound. This house curve barely changed music and made movies more lively. Trust me, this Ultra is no slouch with movies even with a flat curve. 

Here is my house curve I'm going to try with the Ultra:










And here is a pic of the sub's final home:


----------



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

> My graph from last night isn't all that different. According to some of you, the difference between the first two graphs wasn't worth talking about, so I don't see how my latest graph would qualify any different.


Well the first graph had only about a 2-3 dB difference in the 60-70 Hz area - i.e., it dropped from ~72 dB in the brown graph to ~69-70 dB in the blue graph. Now, it's down to ~62-63 dB, a 6-7 dB difference from the blue. _That's_ significant. 

That said, I fully understand that aesthetics in the room often determine final placement. I'm sure you'll be happy either way, once the sub's equalized.



> For some reason, I just like to have a flat curve available. I've tried about 20 house curves with my PC+ and settled on what I call a "4db house curve" that sounded the best. My primary concern is music performance. If music doesn't sound perfect to me, I couldn't care less how movies sound. This house curve barely changed music and made movies more lively. Trust me, this Ultra is no slouch with movies even with a flat curve.
> 
> Here is my house curve I'm going to try with the Ultra:


Well, to each his own - that's what a house curve is all about anyway, tuning the sub to both the room and your personal tastes. I'm happy to see you expermimented with the shelving frequency (20 Hz in your case) instead of perfunctorily accepting my 30 Hz "standard." I wish more people would do that! :T

Regards,
Wayne


----------



## TJHUB (Apr 7, 2008)

Wayne A. Pflughaupt said:


> Well the first graph had only about a 2-3 dB difference in the 60-70 Hz area - i.e., it dropped from ~72 dB in the brown graph to ~69-70 dB in the blue graph. Now, it's down to ~62-63 dB, a 6-7 dB difference from the blue. _That's_ significant.
> 
> That said, I fully understand that aesthetics in the room often determine final placement. I'm sure you'll be happy either way, once the sub's equalized.
> 
> ...


I have no comment on my base graphs. I guess they are what they are...

I've read a great deal on this forum about house curves and how to use them; what works for some and what works for others. I've tried many of the variations, but I've always been my own man and did things my way. 

I really appreciate your input and help. The one thing I guess I'm not getting is whether or not you feel I'm EQ'ing the sub the best way? Am I doing this right? I understand that my ears will tell me over the next few days, but as far as my usage of REW and my BFD?

Thanks.


----------



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

TJHUB said:


> The one thing I guess I'm not getting is whether or not you feel I'm EQ'ing the sub the best way? Am I doing this right? I understand that my ears will tell me over the next few days, but as far as my usage of REW and my BFD?


Everything looks fine, to me at least. :T

Regards,
Wayne


----------



## TJHUB (Apr 7, 2008)

Wayne A. Pflughaupt said:


> Everything looks fine, to me at least. :T
> 
> Regards,
> Wayne


Thanks Wayne. I suspected this is correct. Now I just have to program the filters into my BFD tonight and get some good listening time. I can't wait! :bigsmile:


----------



## brucek (Apr 11, 2006)

> The one thing I guess I'm not getting is whether or not you feel I'm EQ'ing the sub the best way? Am I doing this right?


Here's my suggestion........... add a filter to remove where the arrow points.

Then, add the mains and get the best transition at the crossover.









brucek


----------



## TJHUB (Apr 7, 2008)

To make a very long story short, the sideways orientation just isn't going to work out. EVERYTHING in my room is vibrating and the worst thing is my entertainment center. Even at low volume, things are rattling. I can't even figure out everything that's vibrating! So back to a forward orientation...

I located the sub forward and remeasured:










The filters I used:
Freq. BW Gain
25(-4) 18 -8
40-2 16 -12

Here is the final measurement:










It sounds perfect, nothing rattles in the room, and I used 2 filters. I'll have to live with the tight fit by the chair, but oh well. The Ultra just didn't sound right sideways; even when EQ'd. Orientation of the sub sure made a HUGE difference in my room. Say what you will...

DONE!! :T


----------



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

Very nice - well done! utstanding:

Regards,
Wayne


----------



## TJHUB (Apr 7, 2008)

Wayne A. Pflughaupt said:


> Very nice - well done! utstanding:
> 
> Regards,
> Wayne


Thank you sir. And of course, thank you for all your help. 

Now I've got a lot of listening to do...:bigsmile:


----------

