Collaborative Tapped horn project - Page 28 - diyAudio
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Old 28th April 2007, 05:50 AM   #271
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Me thinks perhaps the Third bend need to be a little bit longer??

It is incredibly potent, down to the 22Hz knee. It doesn't seem to perform quite that great bellow the knee. At 20Hz the mechanical noise of the driver is noticable.

Here are the TS parameters I took from the Kove (Parts Express Buyout) Z12D I think.

dD=27.58cm |Piston
fs=49.7Hz
Mms=120.9g
Cms=0.0000848m/N
Rms=6.309Ns/m
Bl=21.03Tm
Qms=5.986
Qes=.555
Vas=.043m3
Re=6.5ohm
Le=1.595mH
ExpoLe=0.618

Xmax is ~18mm

Its a dual voice coil with 400Watts power handling per coil.

Anyone have any suggestions for alternative drivers.

Antone-
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Old 28th April 2007, 01:34 PM   #272
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Antone, great to see your prototype!

Very interesting results also. I'm suprised to see how flat it is. I have a few questions for you:

1. What are the dimensions?

2. How far have you offset the driver from the mouth end?

3. How do you find excursion control below F3?

4. What efficiency 1w 1m did you find?

From what I've seen it is better to have the driver right in the mouth, yet your results for your prototype look great.

Great work. How did you find the SQ?
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Old 28th April 2007, 02:24 PM   #273
freddi is offline freddi  United States
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good grief Antone ! - response came out pretty darn good. ah - I see the specs above--diyma 12 has a lotta mass but might be good - strange to have dumax yet no qes & qms

since this tread is called collaborative TH project - will there be a project with currently available woofer? I have no experience with these type driver and your high fs Kove seemed to work well. Will Ciare's 12" drop in?

Freddy
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Old 28th April 2007, 05:08 PM   #274
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Hey All,

Paul I'm not sure what you mean by SQ?

I started with The Outs side Dimensions of The DTS-20 and built the inside within those constraints. The driver is centered almost at 44" from mouth I think. I set the mouth to be ~10"

At 22.5HZ I'm predicting around 17mm and at 21.5Hz I'm predicting around 27.6mm

I haven't don the actual 1 W 1 meter I can give it a try ant the ware house but there is too much reflection in here. Everything I've done so far is a couple of inches from the mouth.

A thought occoured to me that the horn path dirrectly infront of the radiator may act as part of the actuall path length so perhaps I need to make it longer?

Freddi, I am going to have to revisit my aKabak to try and get it to resemble my results a little closer. The Ciare looks like it peaks a little more with a Higher F3.

It was a good start and I did ad 5 significant pieces of bracing to the internals plus a center hatch, IT STILL wasn't enough to really take care of issues up in the 60 and 70Hz range, as far as buzzing at high output. It was a lot of fun to remove the driver hatch while I was playing a 20Hz sine, it began oscilating up and down about 1/2 and inch.

Now all that I have to do is figure out how to make it road worthy for a Bass rig. I think I need apair Mu hah hah hahhhh!!

Antone-
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Old 28th April 2007, 05:17 PM   #275
freddi is offline freddi  United States
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is it gonna be a PA/DJ woofer?, de-tuned/ (or octave-dropped synth) bass-guitar woofer? or put two into a van with a bed and lites to make a love-mobile?

Freddy
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Old 29th April 2007, 12:01 PM   #276
Frode is offline Frode  Norway
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Quote:
Originally posted by freddi
--diyma 12 has a lotta mass but might be good - strange to have dumax yet no qes & qms

Freddy
Maybe this will help:

Click the image to open in full size.

Frode
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Old 29th April 2007, 01:23 PM   #277
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SQ = sound quality!

So I'm wondering how it compares in your view to other subs/speakers you have heard when it comes to how accurate it is.
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Old 29th April 2007, 02:04 PM   #278
freddi is offline freddi  United States
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thanks Frode. Whats the story regarding cone rattling issues and where/when might that happen?

Freddy

http://www.diymobileaudio.com/forum/...ead.php?t=6613
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Old 29th April 2007, 03:35 PM   #279
MaVo is offline MaVo  Germany
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A different simulation. This time using a single waveguide as the main part. The driver is connected via ducts to it and the radiator. Perhaps this one is easier to understand then the last one i made. Better to play around with at least. It does modell slightly different then my other script (in the range of a few decibels here and there).

Is it accurate? I dont know, but it sure is interesting to play with. Would be nice if someone who has actual measurements of a real horn could tell me how accurate it is.

The Def_Const is where one can type in the horn dimensions. Xwidth is the width, which is constand for the whole horn. The throat area is defined by Xwidth*Xthroat. The mouth area is Xwidth*Xmouth. Lhorn is the horn length. Ldriver is the size of the driver. The dimensions are in centimeters (hence the e-2, since e0 would be meters).

Just copy paste everything below this sentence in an empty akabak script, hit f5 and click the OK button to see the frequency response.

Def_Const
{
Xwidth = 32e-2;
Xthroat = 10e-2;
Xmouth = 30e-2;
Lhorn = 450e-2;
Ldriver = 26e-2;
}

Def_Driver 'Lab12'
dD=25.2cm |Piston
fs=33Hz Mms=146g Qms=13.32
Bl=15Tm Re=4.29ohm Le=1.48mH ExpoLe=0.618

Driver 'D1' Node=2=0=100=101 Def='Lab12'
Duct 'Dr' Node=101=102 WD={Xwidth} HD={Xthroat} Len={Ldriver}
Duct 'Dd' Node=100=104 dD={Ldriver} Len=3cm
Duct 'Df1' Node=103=104 WD={Xwidth} HD={Xmouth} Len={Ldriver/2}
Duct 'Df2' Node=104=105 WD={Xwidth} HD={Xmouth} Len={Ldriver/2}
Waveguide 'W1' Node=102=103 WTh={Xwidth} HTh={Xthroat} WMo={Xwidth} HMo={Xmouth}
Vf=50mm3 Len={Lhorn-Ldriver-Ldriver} Conical
Radiator 'Rad1' Node=105 Def='Df2' WD={Xwidth} HD={Xmouth}
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Old 29th April 2007, 05:59 PM   #280
freddi is offline freddi  United States
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I must have messed it up and didn't calculate --sure a lot less script
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