# My 3 18.2s calibration thread



## madpoet (Jul 26, 2010)

I have 3 CS-18.2s in a really, really bad room  This thread is about my attempts at calibrating them. Today I took some raw REW measurements and played with my phase. I am totally new to REW so I followed this guide:

http://polaraudio.blogspot.com/2012/01/calibration.html

The black line is with all 3 in the same phase, the blue is with 1 off phase. Not super, but still pretty good considering how awful my room is and absolutely no EQ.

EDIT - This chart is with absolutely no EQ applied yet  Just want to make that clear.


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## craigsub (Sep 9, 2006)

MP - That's quite a peak at around 45 Hz. A couple of questions:

1. Did you use any calibration curves in REW for your microphone?
2. Do you have an EQ available? I think you are using the FP10000Q clone amp, correct?


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## madpoet (Jul 26, 2010)

Well, I litterally did what was in that post above. I've got a Dayton Basic Plus so it's calibrated down to 5hz and I have the calibration file for it. Is that what you mean by a calibration curve? Please remember I know nada about REW!

I am using the 10000Q clone amp. The above measurements were with ZERO eq. I reset my AVR to zero it all out so no Audyssey is engaged. Tomorrow I am running XT32 and will take after measurements. I have a miniDSP on the way as well to provide some additional EQ.


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## craigsub (Sep 9, 2006)

It looks like you have everything dialed in properly. It should be interesting to see what XT-32 does for your response. And rest assured someone will be along to harangue you about doing your vertical graph for more detail (instead of 20 dB at a time). :whistling:


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## madpoet (Jul 26, 2010)

Happy to do it differently if someone explains to me how


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## madpoet (Jul 26, 2010)

Ok I figured out the zoom. This is zoomed to 5db, no smoothing applied. Man it looks a lot uglier  Got some placement work to do tomorrow.


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## craigsub (Sep 9, 2006)

MP - Actually, that curve looks better. You are +/- 7.5 dB from 14 up to about 55 Hz, with a null above that.

I have seen a lot worse IN ROOM responses before eq.


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## engtaz (Jul 9, 2010)

I like the curve in post 1. Looks like you did a great job on your sub setup. Congrats on the new toys you get to play with. Enjoy the bass.


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## sbdman (Dec 21, 2008)

That's a good start to be able to fix a phase problem. I think if you could, try a different location set up to see if you can make it a little easier to tame. The less you have to boost or cut, the more flexibility you'll end up with. Then try Audyssey. Then tweak with the mini-DSP when it comes.


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## madpoet (Jul 26, 2010)

Yeah, that's my goal for today. I want to mark where they are now in case I need to go back, and then try a couple more positions. I am a little limited so there's only a couple more configurations I can try. Once I find the best I can do without any calibration I will then run XT32.


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## madpoet (Jul 26, 2010)

Forgot to also post this over here  Black is pre-Audyssey. I am not thrilled with it, espcially the huge null at 85. It did smooth out the peak some though, and I am pretty decent down to about 12hz. I am going to look over my room again and see if I can come up with a better placement. I feel like room or not I should be doing better with 6 18" drivers.


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## mktheater (May 1, 2007)

madpoet said:


> Forgot to also post this over here  Black is pre-Audyssey. I am not thrilled with it, espcially the huge null at 85. It did smooth out the peak some though, and I am pretty decent down to about 12hz. I am going to look over my room again and see if I can come up with a better placement. I feel like room or not I should be doing better with 6 18" drivers.


It really is room dependent and placement. Sometimes the best place is not where you need the subs. Have you tried just locating all the subs in one spot them move one out to another area and then move the last one to another? Of course that is if you need to. My subs need a boost down low as most sealed do.


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## MikeBiker (Jan 3, 2010)

According to this paper, you would have better results with two subs instead of three. Best would be adding another sub for a total of 4.


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## tesseract (Aug 9, 2010)

The Harman paper is a good read, but based on mathematical simulations assuming a sealed room of given proportions, which is unlikely to be your room or mine. 

Here is the method I believe madpoet is trying. It is a practical guide to setting up subs in real world rooms.


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## mktheater (May 1, 2007)

Are the subs limited to just a few places or do you have multiple areas? If you can I would find the single best location as response is concerned and then put another somewhere to see what happens. The best known places or most coomon are the 4 corners or midwall. I would try a combination of maybe 2 in the corner and one midwall or vice versa. My faorite places are my 2 front corners and right under my center channel. Once you get that location dialed in then move to your next seat and watch what happens! I have so much treatments that my bass stays pretty close in response from seat to seat with the midbass varing slightly.


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## madpoet (Jul 26, 2010)

Very rough sketch of my room. 7' ceilings, hardwood paneling, partially open ceiling to LR above. Carpet on concrete. Stupid support pole dead center.


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## mktheater (May 1, 2007)

Any progress yet?


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## madpoet (Jul 26, 2010)

Got to wait for everyone else to be out of my house  Tonight or tomorrow.


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## madpoet (Jul 26, 2010)

MiniDSP came today, so I am going to spend some quality time tomorrow. Got to move them first, measure, EQ with DSP, measure again, and then Audyssey and measure one last time


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## dguarnaccia (Jul 17, 2008)

To try the Geddes approach, try one in the right corner, a second one around 1/4 along the wall, and the 3rd along a midwall somewhere. the second 2 should be away from the corner loaded one. can also try flipping the 3rd one to get the drivers off the ground. 

Have fun!


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## myc52002 (Sep 3, 2008)

If you haven't already done so reverse the polarity (reverse pos / neg connection) of the sub in the back of the room. I have (3) 18.2 in a bad room as well and for me that was the secret ingredient to getting it right. I actually ended up with 2 in the back and 1 in the front of the room.


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## madpoet (Jul 26, 2010)

Yeah thanks, I did flip the rear. That's what got me pretty good below 20. I have some new mains coming today to allow me to reposition the subs in the front.


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