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15" tapped horn plans |
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MarjanM 
Old Croc 
Joined: 10 February 2005 Location: Macedonia Status: Offline Points: 7816 |
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 Posted: 21 May 2008 at 6:15pm |
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It looks interesting anyway.
Tom uses B&C 15TX100 in TH115. Try to simulate it in akabak. |
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Marjan Milosevic
MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713 |
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Deadbeat
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Joined: 12 March 2008 Location: Singularity Status: Offline Points: 3167 |
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Posted: 21 May 2008 at 6:36pm |
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I knew that!
That's why I put a massive: *This is not a TH115 (Just a notice, for people who search and find these plans). sign afterwards so people wouldn't compare it. The amendment was from THE ORIGINAL DESIGNER of the 'TH-115 STYLE ' Tapped Horn. It was to correct something on the 'TH-115 STYLE ' Tapped Horn plans. I'm now going to put a massive sign on the start, so no more confusion occurs. Just trying to be helpful |
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Away on extended leave.
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_djk_
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Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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Posted: 21 May 2008 at 8:53pm |
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"but if you want to cover 40-100Hz there isn't really anything suitable that still has decent xmax. if anyone sees anything let me know... "
The RCF L12P540 in the design has a good x-max (6.5mm), enough for about 600W program material in the above script (woofer rated at 800W program)
"Yes please DJK is it an off the shelf RCF?"
Yes, I did a search and found a half dozen sources in the USA, all about $180.
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djk
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Disco Stu
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Joined: 03 March 2005 Location: United Kingdom Status: Offline Points: 2487 |
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Posted: 22 May 2008 at 12:17am |
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That looks cool, thanks very much DJK, this may be it, have you got any sim plots of response / excursion etc. you know just to get an idea.
Stu |
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All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
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Disco Stu
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Joined: 03 March 2005 Location: United Kingdom Status: Offline Points: 2487 |
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Posted: 22 May 2008 at 12:49am |
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DJK how does this driver look?
http://www.precisiondevices.co.uk/showdetails.asp?id=63 Its only £80 in the UK |
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All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
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Disco Stu
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Joined: 03 March 2005 Location: United Kingdom Status: Offline Points: 2487 |
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Posted: 22 May 2008 at 11:31am |
DJK can you explain a little more about the v shaped wedge in this section. 1) Do the V shaped parts run the full height of that section? I presume so 2) If so it looks like there is an area at the point of the V where the air will escape down through the fold. Is this just a drawing error or is it meant to do this? 3) Is the area where the yellow dot is the asymmetrical slot that the driver fires through? Stu |
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All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
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_djk_
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Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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Posted: 22 May 2008 at 11:33am |
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The PD looks like it should work OK, its not quite as smooth (the Fs and Qes are a bit low).
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djk
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Disco Stu
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Posted: 22 May 2008 at 11:41am |
Like this |
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All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
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Disco Stu
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Posted: 22 May 2008 at 11:53am |
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Just out of interest, do you know what the net result of extending the path length of the horn without increasing the mouth would be?
How much more box volume do you think would be required to hit 40-45Hz? From the looks of the excursion plot it would be unlikely to work with a 12" you would need a 15" no? The design looks great, and at that price, its quite economical too. Comparing it to something like a B&C Sub 15 Box, it looks as though its got several dB in its favour. What I have yet to see on this forum is a really compact general bass bin that can compete with the size of a reflex 15 and maybe outperform it. I expected it to come from a tapped, and it looks like this may be it. Stu |
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All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
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_djk_
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Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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Posted: 23 May 2008 at 12:18am |
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Yeah, you need to block that 'V'.
Longer will go lower, but will require a 10mm x-max more expensive driver from B&C or Beyma if you need maximum output.
I ran the PD driver in a slightly bigger box 30x30x18(external) vs 24x28x16. It is 3dB down at 38.5hz, and about 100.5dB at 43.5hz, it hits x-max with 35V on a sine wave at about 50hz. With program material crossed at around 120hz or so it will likely handle 600W/8R.
An 18 ( one with a medium Qts to work well in a vented box) in the same size box tuned to 40hz to give it a bit of a bump to 98.7dB at 70hz is over 4dB less efficient at 43.5hz and will need 1KW to hit 126dB vs 400W for the PD 12.
I just bought an NOS pair of Beyma 12LX60 for $100 each (includes freight). I plugged the parameters for the pair into a stacked pair of the bigger PD boxes and got ±2dB from 38hz to 140hz, with over 106.5dB at 42hz with 2.83V input. Full rated power into the pair calculates to 135dB at 42hz (from a pair of 12s?). X-max on sine waves is only about 625W, but on program material they should be able to handle the 1100W/4R that my Crest CKS 1600-2 ($400 on eBay) puts out at 4R.
| 40 Hz Tapped Horn
Def_Const |Horn Dimensions
{
a1 = 150e-4; |Area at throat (cm^2) a2 = 250e-4; |Area at rear of driver (cm^2) a3 = 1300e-4; |Area at front of driver (cm^2) a4 = 1400e-4; |Area at mouth (cm^2) l1 = 10e-2; |Distance from throat to rear of driver (cm) l2 = 240e-2; |Line distance from rear of driver to front of driver (cm) l3 = 25e-2; |Distance from front of driver to mouth (cm) } Def_Driver 'Dr1'
| PD.12SB30
Sd=530.9cm2
fs=50.238Hz Qes=0.316 Qms=5.024 Vas=58.945L Re=5.493ohm Le=1.773mH system 'S1'
Driver Def='Dr1' Node=1=0=3=4
Waveguide 'W1' Node=2=3 STh={a1} SMo={a2} Len={l1} Conical Waveguide 'W2' Node=3=4 STh={a2} SMo={a3} Len={l2} Conical Horn 'H1' Node=4 STh={a3} SMo={a4} Len={l3} Conical And a quickie box, same type throat as the other one, reversed, with one more section after it.
  Edited by _djk_ - 23 May 2008 at 11:05am |
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djk
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rich, ind.st
Young Croc 
Joined: 14 January 2005 Location: United Kingdom Status: Offline Points: 1096 |
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Posted: 23 May 2008 at 1:16pm |
hmmm, very interesting.... |
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music is god
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Disco Stu
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Posted: 23 May 2008 at 1:54pm |
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Aha thats cool, I think 30x30x18 is a bit out of my league size wise, I am hoping to keep it close to the B&C Sub 15 size which is what I am using now and your 50Hz tapped box if built from 12mm and well braced would work out to be in the region of 161 litres vs 158 litres which for the performance gain and weight reduction would be quite acceptable.
I already hipass at 40Hz so I dont really need anything below there, and the majority (read 99.9% of my work is live band) so do you think the 50Hz tapped would be the one to go for, do you think I will miss the last 10Hz? With regard to amping I am unlikely to ever need more than a pair of subs but I use a PLX1802 which gives 600 into 8 or 900 into 4, is there a 12" with more Xmax that I could try and get in a 4 Ohm version that would benefit from being able to take the extra brunt of the 900W, or do you think its better to just stick with 8 Ohm cabs run with 600W per box and then add an extra cab per side if and when needed? I dont mind if the driver is a bit pricey so long as its going to give me good performance, availability in the UK is probably important so B&C, Beyma and 18 Sound are probably easier to get hold of than RCF, I checked out that driver you pointed me to before and only found one source with no prices. Thanks Stu Edited by Disco Stu - 23 May 2008 at 2:01pm |
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All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
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_djk_ wrote: