sub localizing

**dimmie** · **11-15-06, 01:59 PM**

Hey shacksters!,

I've been playing around with house curves and and applying filters to my sub and I've come a pretty long way in doing this correctly and achieving a pretty good result. With a lot of help from the moderators here.

But I have been facing some problems still, one of which is subwoofer locatability at certain frequencies. And I'm not just talking about the frequencies which are known to be directional, but also below 80 hz.

Could anybody give me some pointers in the right direction to solve this problem. I believe phase and distance setting are right.

I'll send along 2 graphs, one before and one after EQ.

Thank you,

Dimitri

**Wayne A. Pflughaupt** · **11-16-06, 05:52 PM**

Quote:

But I have been facing some problems still, one of which is subwoofer locatability at certain frequencies. And I'm not just talking about the frequencies which are known to be directional, but also below 80 hz.

Some people, it seems, can localize lower frequencies. I’m one of them, too. However, I expect it’s the upper subwoofer frequencies that we localize, not the lower ones. It seems like the sub is always easy to localize because almost any bass signal is a “mixture” or frequencies and harmonics, not a pure tone.

As far as what to do about it, all I can come up with is play some 12-octave sine waves from 20 Hz and up, and see at what point you are able to localize the sub, then move your crossover frequency accordingly. Sonnie has some sine waves at his BFD Set Up Guide. You can download them and burn a disc. Look at the graphs in my subwoofer comparison test sticky thread at our Subwoofers Forum for the 12-octave intervals.

Regards,
Wayne

**terry j** · **11-16-06, 08:18 PM**

Within REW itself you can opt for 1/12 th ( or higher ) tones, and do an automatic sweep. Saves burning a cd etc

Just change the sweep option to whatever you want, can even do 1hertz at a time.

lots of love

terry

**dimmie** · **11-17-06, 01:54 PM**

Thanks for your replies guys,

But I'm kinda bound to my 100 hz. crossover wayne, because I'm using kef sattelites which don't take well to the 80-100 hz. region. The highs sound much clearer at 100 x.

I did trie to lower the x over to 80 hz., but sometimes the bass was quite directional also. So I'm wondering if it maybe poor subwoofer placement is an issue here....

Do room resonances induce sub locating?, the frequencies that were an issue before eq, maybe those are the problem still, in the form of directional bass.

Dimitri

I'll see what I can do with some freq. tests

**Josuah** · **11-17-06, 09:05 PM**

It might be localizable due to boominess? Can you tried moving the sub farther away from the wall/corner? Is your room not well treated? (The before EQ kind of says it isn't well treated.)

**dimmie** · **11-18-06, 01:21 PM**

Quote:

Josuah wrote:

It might be localizable due to boominess? Can you tried moving the sub farther away from the wall/corner? Is your room not well treated? (The before EQ kind of says it isn't well treated.)

No, I didn't use any type of room treatment, I kinda hoped the BFD would be enough. But the point you're making is exactly what I meant. That it's just room resonances in a different form.

**Josuah** · **11-18-06, 09:13 PM**

You need room treatments then. EQ only adjusts SPL. It doesn't fix decay or interference or reflections.

**terry j** · **11-20-06, 02:41 AM**

to test your theory about being able to hear where the bass is coming from, is it possible to disconnect your mains, and then set a lowpass filter(s)-(for the sake of argument let's say 100 hz), make the filters act as a lowpass I mean, and then seeing if you can locate where it's coming from. It should be a simple matter to vary the 'lowpass' point to see at what frequency you can locate the subs with. Not having the mains 'blaring' at the same time may help you determine if it is the sub you are hearing or resonances etc.

I don't propose to suggest how you may set your filters, but it doesn't seem as if it would be hard to set up a shelf low pass filter.

hope you understand what I meant ha ha

lots of love

terry

**dimmie** · **11-20-06, 12:58 PM**

Thank you for your input terry,

But I'm not sure I fully understand what you mean with setting a low pass filter.

You mean create a new set of filters on the BFD?, and filter out everything above 100hz.?

Thanks

Dimitri

**terry j** · **11-21-06, 12:52 AM**

yeah, just as an experiment. It's not a major hassle to 'wipe the slate clean' and start again. However, the purpose this time would be quite specific, ONLY have the sub(s) playing, and ONLY below a certain frequency.

By starting low and working your way up the frequency range, there will presumably come a point where the sub becomes localizable. There's your answer to what frequqncy is your cutoff point for being able to localize the sub.

Rattles and rumbles, buzzes etc will probably be easier to ascertain withgout the mains going, and you will be able to better answer the question of whether other audio clues other than pure frequency help localize the sub.

Of course, once you know what's going on, you can then redo your filters for the permanent setup, armed with new knowledge of what's happening.

At the very least your 'guessing game' gets put onto a concrete foundation. Hope that is a bit clearer, I admit my last effort was rather poor!

lots of love

terryh

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