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Old 24th March 2013, 09:22 PM   #41
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Alright. I'm going to the city tomorrow anyways so I'll try to find some place that has selfadhesive sealing strip, M6 bolts and M6 t-nuts.
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Old 8th April 2013, 09:19 PM   #42
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I have everything up and running now. Finding the bolts and nuts proved to be a hell of a work. After hours of biking in a wet and muddy town I found the bolts. The nuts I ordered from Thomann along with amplifier, cables and damping material. I found some self adhesive strip in my garage, but it was a bit old so the adhesive was really bad so it fell off on one of the drivers so there's a tiny tiny leakage.

First thing that has to be done is fan-modding the Behringer. The fans are loud and blow a lot of air on me which makes me freeze. I'll to add some resistors to run them on something like 5-7v. If they're still too loud I'll try some other fans.

Next step is to set up the EQ. I gave it a try today but I didn't think clearly at all so instead of lowering the peaks I boosted the gaps so I guess it's distorting a bit now. Will give it another try some other day, hooking it up to my computer so I can more easily see the curves.

They do play flat down to 20Hz though. Maybe lacking a little SPL capability, we'll see when I have got everything set up right. I'm already considering going with a ported box instead.

Is it a bad idea to have one ported box (100l tuned to 22.7Hz) and one sealed box? I can EQ, XO, adjust volume and even delay them separately. If so I was thinking of having the big ported box between the mains and the smaller sealed along the right wall. Right now both of them is placed between the mains but if I move one to the right wall I would easily have space for a 100l box between the mains.
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Old 9th April 2013, 12:41 AM   #43
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Originally Posted by Rullknufs View Post
First thing that has to be done is fan-modding the Behringer. The fans are loud and blow a lot of air on me which makes me freeze. I'll to add some resistors to run them on something like 5-7v.

Is it a bad idea to have one ported box (100l tuned to 22.7Hz) and one sealed box? I can EQ, XO, adjust volume and even delay them separately.
Some have reported running the fans in series quieted them down nicely.

The most important place to line up the phase response of your subs/tops is in the crossover region.

Both ported or sealed subs will have the same phase response in the upper range, so the tops (or subs) will require the same delay for phase alignment.
Around and below Fb (the tuning frequency) the phase will rotate more on the ported subs, at and below FB it will be 90 degrees off, so can't be corrected without messing up the upper response.

In room, the 90 degree phase change between cabinets may or may not be terrible, but probably won't be good as far as combining ported with ported or sealed with sealed.

The screen shot below is a 2xLab 12 of about 151 liter with an FB of 36 compared to the same cabinet with the ports closed, measured outside at two meters.
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File Type: png Ported,Sealed.png (128.1 KB, 151 views)
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Old 29th May 2013, 08:00 PM   #44
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Done some in-room measurements and I have some annoying problems... I have gotten it pretty darn flat from like 85Hz and down but above that it is crazy.

Here's a picture of a full-range frequency measurement. I don't know if it can be trusted in the very deepest bass, seems a little too good to be true, and the SPL is way off from reality, take it down maybe 15dB and it's more accurate.
Click the image to open in full size.

Right now the subs are XO:ed at 120Hz with a 24dB/octave BW filter. The main speakers are crossed over at 80Hz with the same type of filter. I though this overlapping would help the big dip at around 100Hz and it did slightly but it doesn't matter if I add a big EQ to the spot or invert phase of subs. It's still there and the several other dips a bit higher up as well.

So far I haven't gotten to moving around the subs but I sure will try that some day.

What do you think? I see the phase goes crazy where the dips are but I know too little about phase to draw any conclusions to what might be causing the problems.

Edit: I found a laser distance meter in dad's room and I quickly measured the room. It's about 3.8x3.8 metres and the height is 2.4m.
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Old 29th May 2013, 08:53 PM   #45
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Done some in-room measurements and I have some annoying problems... I have gotten it pretty darn flat from like 85Hz and down but above that it is crazy.

What do you think? I see the phase goes crazy where the dips are but I know too little about phase to draw any conclusions to what might be causing the problems.
A 30 dB hole in the crossover region is not a good indication of proper alignment .
The speakers probably need to be underlapped, overlapping is an invitation for the problems you are seeing and hearing.

Try doing individual tests of a single sub and a single main crossed with a BW 24 at 100 Hz so we can see what they look like without combining.

Also include a diagram of speaker and mic positions in the room, and your listening position.
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Old 29th May 2013, 09:24 PM   #46
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Here's an older measurement, I don't think I had the subwoofers connected then.
http://4.bp.blogspot.com/-MU3JyXNCe2...C3%A4tning.jpg

Here's a quick measurement I did now with only the main speakers connected, running full-range without EQ.
http://i.imgur.com/EEeYpPS.jpg
I can take some pictures tomorrow and try with different XO points like you said.
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Old 29th May 2013, 09:33 PM   #47
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I can take some pictures tomorrow and try with different XO points like you said.
Looks like your main speaker's response has 10-15 dB dip at 100 Hz, do some close measurements to determine if that is a room or cabinet problem.
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Old 29th May 2013, 09:55 PM   #48
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http://i.imgur.com/amH0YdL.jpg

Mic 10cm on-axis from the upper woofer (D'appolito configuration). Only right channel speaker playing and being measured. Seems pretty flat to me...

Edit:
Here's measured on-axis 10cm from the tweeter which is between the two woofers.
http://i.imgur.com/mLtnhIp.jpg
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Last edited by Rullknufs; 29th May 2013 at 09:59 PM.
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Old 30th May 2013, 05:19 PM   #49
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I'm waiting for you to take a look at the close measurements before I start experimenting more with different crossovers.
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Old 30th May 2013, 08:42 PM   #50
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Mic 10cm on-axis from the upper woofer (D'appolito configuration). Only right channel speaker playing and being measured. Seems pretty flat to me...
Top speaker seems flat, so your room, placement and/or crossover are resulting in the peaky response.

Looks like 80-100 would be a reasonable place to cross the tops and subs.
If the tops are ported, you may try closing the ports (socks work well for temporary blocking) for a more even phase response in the crossover region.
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