TH-18 Flat to 35hz! (Xoc1's design) - Page 115 - diyAudio
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Old 14th October 2012, 07:11 AM   #1141
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Hi rpowell,
I have heard a rumor that a new design will be put up,but no you haven't missed it ,This cab I built I did with some help from everyone here's Ideas ,I am learning hornresp ,I used a protractor and made the curves,each turn gets about 10% bigger,I used 400mm lenght for the part#10 ,If someone would like to run it in hornresp I would like to see how close it is,
It got to Play music tonight but the cone is stiff ,but it sounded good ,I am new to rew but what I did run looked reasonably flat and no big bumps or dips,I was happy with it ,bass filled the room EZ,I have 2 more stiffeners and the broom stick to put in tomorrow,
Regards
NS

Last edited by noSmoking; 14th October 2012 at 07:15 AM. Reason: speller
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Old 14th October 2012, 11:47 PM   #1142
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Does the 1st TH-18 have a 3:1 compression ratio and 2nd version a 2.5:1? Am I remembering (somewhat) correctly?
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Old 15th October 2012, 04:33 AM   #1143
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Hi CRESCENDO,
I think that is correct,I didn't do these in hornresp,Trail and error,Djim helped me along with those he might be able to give some more exact figures on hows and whys,
The first one is breaking in and starts coming on at 20HZ or so,The second one is not broke in and starts about 40 hz but I think that will change as it loosens up some ,
I was wondering if you would post what you did for horn correction,I would like to see! I hope to make some measurements with REW tomorrow ,I don't have any plans but to run them,,,I hope ,lol.
Regards,
NS

Last edited by noSmoking; 15th October 2012 at 04:39 AM.
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Old 15th October 2012, 08:55 AM   #1144
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Quote:
Originally Posted by noSmoking View Post
I was wondering if you would post what you did for horn correction
I took the baffle cut-out, a 3/4" piece 6.75" wide on top of it and a 3/4" piece 2.5" wide on top of that, glued & screwed to the opposing wall centered over the driver.
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File Type: jpg TH-18 cone correction1.jpg (336.3 KB, 499 views)
File Type: jpg TH-18 cone correction2.jpg (395.0 KB, 474 views)
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Old 15th October 2012, 12:22 PM   #1145
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by noSmoking View Post
Djim helped me along with those he might be able to give some more exact figures on hows and whys
Hi guys,
How can I give "more exact figures" when I don't have any dimensions? To sim it, I will need the exact dimensions...
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Old 15th October 2012, 07:15 PM   #1146
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Hi,
I will get the deminions to him,

CRENSENDO looks like what I did too but I did cut another a smaller piece for the left side or the out side and that did the trick,I had also put 2 layers 1 was 80% of the cut out and the top layer was about 60% ,I put both layers in and I think it choked it off,Volume was low and bass wasn't there,immediate effect.lol. so took out one top piece from the small side of the throat,and it was on then sound and bass returned, I'll have to look for the pic I think I have one of it.
Regards
NS
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Old 15th October 2012, 07:27 PM   #1147
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Hi
I did a pic mod and this is what I ended up with,I could have tapered the edges but I didn't.
NS
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File Type: jpg 1st stub_MODDedhf.jpg (56.9 KB, 442 views)
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Old 15th October 2012, 09:33 PM   #1148
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Hi,
If anyone would like to help me out with a sim or hornresp here is what I change all the other measurements are the same,THANKS in advance,any help I can offer just ask!
Thanks alot,
NS
Attached Images
File Type: jpg BOX 2 drawing to cone correction.jpg (291.8 KB, 426 views)
File Type: jpg img020.jpg (920.7 KB, 420 views)
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File Type: pdf 294-677.pdf (86.9 KB, 86 views)
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Old 15th October 2012, 09:42 PM   #1149
Xoc1 is offline Xoc1  United Kingdom
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Hi All
Just trying to keep up with developments. Good to see all the effort that people are putting in to developing this design.
Crescendo - Both mk 1 and Mk2 speakers were eventually simmed with a 2.5:1S2 compression ratio. The difference being that the Mk1 does not take into account the volume of the cone while the mk 2 does. in practical terms this means the mk2 has a higher compression ratio.
I see you have modded your Mk1 speakers throat with a coule of layers of 18mm timber
Did you ever manage any measurements?
What would you say was the subjective result of the throat mods?
No Smoking . Really good to see your build pics Are you saying you have a Mk1 speaker which you have now added a fairly radical throat mod which is now giving you improved results, and a second cab which is a Mk2 style cab which is still pending measurement?
Rpowell - I have not posted any detailled drawings of a Mk2 cab yet. I have not had the time to get on with it recently.
Also I am not confident yet that we have really nailed which is the best way to impliment the throat changes. it really does take the time and effort of people like Nosmoking and Crescendo who are prepared to put their resources into building and testing these cabs to push this design forward.
Regards
Xoc1
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Old 16th October 2012, 02:42 AM   #1150
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Well technically one can still build the mk1 and get good results. I just passed my pair on to a local DJ who absolutely loves them!!

Now I'm sure mk2 will be better,
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