TH-18 Flat to 35hz! (Xoc1's design) - Page 22 - diyAudio
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Old 24th June 2011, 02:13 PM   #211
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Right now I've got 2 Crest CA9's and 5 QSC CX502's. Power isn't going to be an issue, finding a place to store them...


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Good choice , any ideas about the amps yet?
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Old 24th June 2011, 03:33 PM   #212
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Each one of the crest bridged should provide enough power for the sw115's, but i don't think the qsc's will put out enough to really drive the sub....
I'm probably going to have to grab another xti 4000 and run each one bridged to each cabinet :/
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Old 24th June 2011, 04:38 PM   #213
Djim is offline Djim  Netherlands
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"Enough" is relative concept but one xti 4000 for one 18LW2400 is asking for trouble
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Old 24th June 2011, 06:58 PM   #214
epa is offline epa  Netherlands
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I know, so don't use perforated steel. Look in the industry for weaving-wire. It is used in filter technique a lot. Here in the Netherlands we have Averinox in Haarlem.
Click the image to open in full size.



Another option is concrete mesh with small openings (10x10cm). On the ends you iron rings for attachments. It's very cheap and very strong.
Click the image to open in full size.



As a third option, at gardening shops they sell steel plant-holders for wall attachment. It doesn't have the relief on the steel like concrete mesh but it is more expensive.
Click the image to open in full size.
i think factory floor stuff would be as stiff .... as anithing
this is what i mean.
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Click the image to open in full size.
you can get them in varius thicknesis and size's
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Old 24th June 2011, 07:19 PM   #215
Djim is offline Djim  Netherlands
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i think factory floor stuff would be as stiff .... as anithing
this is what i mean.You can get them in varius thicknesis and size's
Epa, we used the same stuff from aluminium once that we took out "ouwe postbank hokjes" it was claimed 'hufterproof' and served as safety screen above the bullit glass windows. But 'sjonges' that stuff is expensive if you want to buy it new (over 100ballen per vierkante meter).
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Old 25th June 2011, 02:45 AM   #216
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The QSC's are actually for my Tannoy V series cabs: 7 - V8's, 1 - V12, 2 - V15's also have 2 Power V15's. I do some small production stuff and also use it for a semi-portable outdoor theater with a Integra THX Ultra2 XLR output receiver and Media Matrix X-Frame88 processor. It only started as a hobby HAHAHA

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Originally Posted by m R g S r View Post
Each one of the crest bridged should provide enough power for the sw115's, but i don't think the qsc's will put out enough to really drive the sub....
I'm probably going to have to grab another xti 4000 and run each one bridged to each cabinet :/
OK now to the point. The grill if going over the outside edge of the mouth only obstruct it 1/4" on three sides, Akabak shows only a MAX 0.13dB drop and I can live with that for the added rigidity. Another thought is that vibration looses you some SPL so you may make up that minimal loss and then some in reality

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Last edited by TundraLTD; 25th June 2011 at 03:03 AM.
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Old 25th June 2011, 10:37 AM   #217
epa is offline epa  Netherlands
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Originally Posted by Djim View Post
Epa, we used the same stuff from aluminium once that we took out "ouwe postbank hokjes" it was claimed 'hufterproof' and served as safety screen above the bullit glass windows. But 'sjonges' that stuff is expensive if you want to buy it new (over 100ballen per vierkante meter).
yes expencive for alu or heavy in steel,maybe a scrap jard?
maybe its an ideer to curve mesh/perfed alu, horizontal and and put 1 or 2 bars in vertical.it would stiffen the grill by a lot , and stops it ratling /fibrating.
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Old 25th June 2011, 02:45 PM   #218
Xoc1 is offline Xoc1  United Kingdom
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OK now to the point. The grill if going over the outside edge of the mouth only obstruct it 1/4" on three sides, Akabak shows only a MAX 0.13dB drop and I can live with that for the added rigidity. Another thought is that vibration looses you some SPL so you may make up that minimal loss and then some in reality
I had concidered mounting the angle framed grill on the external face of the box by rebating the edge but see two practical issues.
1: How to finish the top edge of the grille where you have a rough open edge?
2 : The external edges of the box would be fairly square and sharp - with no way of rounding them off. This won't be a problem untill the first time you trap your fingers between the steel and a door frame.
I know from experience what happens when moving a heavy bass bin and trapping my hand on a square edge. A 90deg edge will cut through the skin with enough inertia behind it

Anyway the information on the dB drop with the mesh is very interesting.
What was the percentage open area that you calculated this with?
Regards
Martin.
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Old 25th June 2011, 04:32 PM   #219
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I don't know if this makes a difference or not, but didn't I read that akbak does NOT factor in the "bubble" around the horn mouth, and hornresp does? I'm not sure what equations go along with the "bubble" calculation, but maybe that makes a difference.
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Old 25th June 2011, 06:11 PM   #220
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I just ran a sim with only 50% open area at the mouth and it still only drops 0.51dB @100Hz. As far as the 'Bubble' I believe that is because Akabak only calculates as if it were in a 2Pi environment

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