And yet another before and after

**gsmollin** · **05-08-06, 09:17 PM**

Here are two graphs. The first was the first sweep I took a jpeg of, and is before equalization. The levels also are not calibrated, as it was a lot louder than the graph indicates.

The second is the current results, with a BFD equalization, and just as important, an adjustment of the delay between the main speakers and the subwoofer. Without that, there is a bad crossover notch at 80 Hz, where the mains take over. BTW, I always equalize with all the speakers running, since that's the way I listen.

**brucek** · **05-08-06, 10:09 PM**

Can you tell us what the blue line in graph 1 and 2 represent?

It's hard to get a feel for what you've done with the mismatched levels in the vertical axis between both graphs.

The filtered graph is certainly flat. I would consider a response such as this to be lacking bass. Is this true?

brucek

**Sonnie** · **05-08-06, 11:40 PM**

That first blue line is a speaker target with the crossover set. He just didn't use the sub tab. The second one is a flat target line with no crossover setting. I think.

gs... check out this thread post #2 and set your graph axis limits as such so we have some steady comparisons. This will help us better compare to what we are use to looking at.

Looks pretty flat either way though. I've actually been listening to mine flat of late and seem to like it for some reason. Goes completely against my philosophy though.

What can I say?

**gsmollin** · **05-09-06, 08:27 PM**

Quote:

brucek wrote:

Can you tell us what the blue line in graph 1 and 2 represent?

It's hard to get a feel for what you've done with the mismatched levels in the vertical axis between both graphs.

The filtered graph is certainly flat. I would consider a response such as this to be lacking bass. Is this true?

brucek

The blue lines are the "house curves". They are used by REW to calculate peaks and set the filters in the BFD automatically. The top house curve is for a small speaker with a crossover. It is the default channel that comes up in REW. It is best if you just ignore it, since it doesn't mean anything unless you are equalizing against it.

I suppose I could set the filters to bypass and get another set of graphs. I'm used to looking at curves like that on different axes, and I scale them in my head. Next time I've got some time, I'll take another "before" curve.

The flat line is not lacking bass. It reproduces bass when it is really there, but does not intrude when it's not. I don't like to have the coffe cups rattle on the table everytime somebody closes a door in a movie, and a bass-boosting house curve is downright obnoxious with music. Of course, many people think otherwise, and when they are equalizing their subs, they add a non-flat house curve.

**gsmollin** · **05-09-06, 08:34 PM**

Quote:

Sonnie wrote:

That first blue line is a speaker target with the crossover set. He just didn't use the sub tab. The second one is a flat target line with no crossover setting. I think.

gs... check out this thread post #2 and set your graph axis limits as such so we have some steady comparisons. This will help us better compare to what we are use to looking at.

Looks pretty flat either way though. I've actually been listening to mine flat of late and seem to like it for some reason. Goes completely against my philosophy though.

What can I say?

Yes, I'll take another set of graphs for you, one of these days, and show it on a consistent set of axes. Sorry dude, but I've been looking at Bode plots for about 40 years, and I automatically scale them in my head.

Yes, the flat line shows no crossover setting. The crossover is at 80 Hz. The notch at 50 Hz is related, although I'm just a little unsure why its there. As I adjust the phase control in the sub, and the time delay in the AV receiver, I can get the crossover notch at 80 Hz to flatten out, but just as I do that, another one begins to drop down at 50 Hz. It's at minimum the way you are seeing it, and it's only about -1.4 dB. Not bad, but I don't understand why there are two, and that bugs me.

The "after plot" is way flat. I don't think I've ever done a better job, although I've usually been in large rooms that get pretty squirrely at bass frequencies.

Sonnie, maybe your musical taste is maturing. I find that the flat curve sounds the most like live music- I mean live acoustic music. Even a pipe organ doesn't rattle the windows.

**Sonnie** · **05-09-06, 09:23 PM**

Those blues lines are not really what you would call house curves... they are the target response lines... which could be set up for a house curve if you wanted, but in those graphs above they are anything really... just there.

I agree that the small twitch you got at 52hz should be negligible. If you graph as referenced in the Tips thread then you won't notice as much as you do now as far as looking at a graph.

What a lot of people are doing with the BFD (if you have the 1124) is setting up two presets... one that is flat for music and another that has a house curve for movies. It seems like though, that since I got my two SVS subs that I don't seem to need the house curve like I did when I had my one HGS-15. The bass seems like it's really too much with the house curve in there. I have to admit that there have been a couple of movies where I had to flip it back to the house curve because there didn't seem to be quite enough bass. But the heavy hitters like King Kong and Fantastic Four that have lots of bass just plain out sounded better flat.

Btw... what mic are you using and did you use any correction values?

**gsmollin** · **05-10-06, 08:32 PM**

I use the Behringer ECM8000, sometimes two. It is (they are) connected to a UB802 preamp. I don't use a correction curve, since the mics aren't custom-calibrated.

The correction values were entered by hand. It wasn't much of a chore, and I don't think I would bother with a midi interface unless I were doing a full range equalization.

BTW, I did take some full-range data too. It required a lot of averaging to eliminate the standing waves in the room that cause so much trouble with a mic that has the 1/4 inch capsule. I used two mics, and 8 trials, moving the mics between the trials. The graphs are interesting, since they show that below 200 Hz, the response is independent of position, and becomes increasingly sensitive to position as the frequency goes up. Averaging removes the response notches, and reveals a mean room response.

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