TH-18 Flat to 35hz! (Xoc1's design) - Page 156 - diyAudio
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Old 14th February 2014, 08:54 AM   #1551
Pabesco is offline Pabesco  Bahamas
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good day to all. this is a picture of the two cabs i built. i used the original design before lerning about all of the internal bracing. i used all four of the reflectors and went back in later and installed two braces where i could.this is a picture from when i first started the build and had to ink in the reflectors and added braces, sorry for not having a proper picture.

http://www.diyaudio.com/forums/attac...1&d=1392381194

i am using 18sound 2400s in them and recently added new equipment to my system. i havnt hardly used these while waiting to upgrade my system
here is a list of what i have now

two th18 subs loaded with 18sound 2400s
two jbell12 tops (dayton 310-8 and selenium 220ti-8 compression drivers)
two dual 18 cabinets
two single 18 sub cabinets
beringher inuke nu6000dsp
crown macrotech 3600
crown macrotech 2402
qsc rmx 2450
DBX driverack DRPA+

Firstly i would like to know if the th18s will be ok without the remainder of the bracing as they have been glued and cannot be opened without major damage. also would the 18sound 2400s be ok using in these cabs and if so set to what hpf and lpf as to not burn them up.
if anyone out there has had experience with the driverack drpa+ would you be able to help me with setting up my system properly so as not to damage anything.
if any of this is not supposed to be posted here i do apologise but i really do need some professional opinions. i have learned alot by reading this forum but want to be sure not to damage my system.
thank you all and have a great day
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Old 14th February 2014, 09:15 AM   #1552
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I believe the TH18 w/2400 needed a Hpass at 30hz second order or more. IN regards to your lack of bracing I think you may lose some spl compared to one with more bracing. I couldn't tell you the exact db loss though.
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Old 14th February 2014, 05:04 PM   #1553
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Originally Posted by wae View Post
Well not ONLY / OR better

You want the TH to be build like it is modeled. NOT using reflectors leaves you with "extensions" in each corner, thus NOT the TH you have simmed.

kind regards,

Frans
I disagree. If the th simmed is 400l and the th built is 400l, then you've built what you modeled. Since added reflectors reduce volume, then you have to build a larger enclosure to get that reduced volume back.
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Old 14th February 2014, 05:30 PM   #1554
NEO Dan is offline NEO Dan  United States
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I disagree ; )~
If the reflectors maintain the correct expansion then the build is correct. Without reflectors you would have small volume gains in the corners assuming the layout is correct...
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Old 14th February 2014, 08:25 PM   #1555
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In a single fold 10ft th, I want YOU to show how the VOLUME stays the same by adding reflectors to the top 2 corners WITHOUT lengthening the horn???
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Old 14th February 2014, 08:32 PM   #1556
NEO Dan is offline NEO Dan  United States
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The trick is to hit the target for all three parameters length, expansion, and volume. I never said it was going to be a cake walk.

The low tech KISS method is to not fold, use two drivers and exit on both ends...
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Old 14th February 2014, 08:33 PM   #1557
Mark Kravchenko --- www.kravchenko-audio.com
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Quote:
I disagree. If the th simmed is 400l and the th built is 400l, then you've built what you modeled. Since added reflectors reduce volume, then you have to build a larger enclosure to get that reduced volume back.
Quote:
I disagree ; )~
If the reflectors maintain the correct expansion then the build is correct. Without reflectors you would have small volume gains in the corners assuming the layout is correct...
Two sides of the same coin. The reflectors change the volume so yes there is a difference. But we have all seen models that take every little corner and crevice into account, and then a simpler model produce the same response curve.

Short but sweet it matters in some situations and not in others.

It's what makes this stuff so interesting!
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Old 14th February 2014, 08:34 PM   #1558
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Correct expansion is less important than correct volume. I think jbell proved that fact with his ss15. I think he stated he lost dB when he added reflectors to the enclosure. In order for reflectors to work, he would have to increase the size of the enclosure, which would kill the single sheet status.
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Old 14th February 2014, 08:37 PM   #1559
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Originally Posted by BP1Fanatic View Post
In a single fold 10ft th, I want YOU to show how the VOLUME stays the same by adding reflectors to the top 2 corners WITHOUT lengthening the horn???
The extra cabinet stiffness the reflectors impart may slightly increase upper response at high level, but the cabinet volume is reduced by the reflectors, reducing LF output by a tiny bit.
The horn path length remains the same, so the LF cutoff does not change.
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Old 14th February 2014, 08:52 PM   #1560
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Originally Posted by weltersys View Post
The extra cabinet stiffness the reflectors impart may slightly increase upper response at high level, but the cabinet volume is reduced by the reflectors, reducing LF output by a tiny bit.
Looks like a good argument to me for not including reflectors, if the bracing provides enough stiffness already.
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