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-   -   Cheap 10inch woofer in tapped horn? what would you do? (http://www.diyaudio.com/forums/subwoofers/180121-cheap-10inch-woofer-tapped-horn-what-would-you-do.html)

ThyDntWntMusic 31st December 2010 05:03 AM

Cheap 10inch woofer in tapped horn? what would you do?
 
figured I'd ask for peoples ideas and suggestions, I've already modelled a few boxes, but thought I'd hear what other people might do :)

also make it easier for me to keep track of the specs, which are manufacturer supplied, although I'd like to measure them for myself some time.

* Power: 300W RMS
* Peak Power: 600W
* Frequency Response: 40Hz - 1.5KHz
* Sensitivity: 87dB/1m/1w
* Fibreglass Composite Subwoofer Cone
* Vas: 26.903
* Impedance: 4 ohm
* Qms (Mechanical Factor): 3.312
* Qes (Electrical Factor): 0.478
* Qts (Total Q-Factor): 0.418
* Fs (Resonance): 45Hz

assuming we measure half the width of the surround when calculating the sd, the diameter is 20.5cm, so SD is 330cm^

re measures 4.2ohms

and most importantly, they're purdy! so I'd like to have the cones on display :o

http://img46.imageshack.us/img46/3769/purdyw.jpg

tinitus 31st December 2010 05:30 AM

my, they must be stiff as hell
car woofers, surely

if they are all yours, make two line arrays, closed, and lots of Eq

Xmax ?

ThyDntWntMusic 31st December 2010 05:35 AM

Quote:

Originally Posted by tinitus (Post 2416161)
my, they must be stiff as hell
car woofers, surely

if they are all yours, make two line arrays, closed, and lots of Eq

Xmax ?

I don't discriminate against "car" and "home" woofers.

there really isn't a difference, they both have magnets and coils!

don't know X-Max, I'd guess somewhere around 5 - 10mm one way :p

I've currently got them modelled in a 2.4m long (total) tapped horn.

165cm^ throat, 330cm^ mouth, with the woofer 15cm from each end.

it gives a theoretical 103dB 1w down to 40Hz, but the mouth just seems way too small to yield that kind of efficiency.

ThyDntWntMusic 31st December 2010 07:05 AM

the aim is 150dB, at 30Hz, in a 4 meter X 6 meter room...

I wanna do hair tricks!

chris661 31st December 2010 08:54 AM

How many drivers do you have?

You will need a very very very large horn to get 150dB@30Hz. With the 300w power rating of one driver, you'd need a starting efficiency (when horn loaded) of around 125dB (at one watt). Let's not get started on the excursion at that much power.
It sounds to me like you'll need more than one driver.

Chris

ThyDntWntMusic 31st December 2010 09:02 AM

Quote:

Originally Posted by chris661 (Post 2416237)
How many drivers do you have?

You will need a very very very large horn to get 150dB@30Hz. With the 300w power rating of one driver, you'd need a starting efficiency (when horn loaded) of around 125dB (at one watt). Let's not get started on the excursion at that much power.
It sounds to me like you'll need more than one driver.

Chris

http://img839.imageshack.us/img839/4041/brrrpt.jpg

David_Web 31st December 2010 10:16 AM

If room gain will add another 12dB (and corner placement is lossless) it could be done.

I would suggest four TH with four drivers each.
I landed around 336L internally per box.
S1 600 and S4 1500. Par. 320cm total length.

As you already have the drivers, go for it. You can't really beat much more performance out of them anyway.

If you didn't try to press so much SPL out of them 8 T-TQWT (with two drivers each) would be neat for a HT.

ThyDntWntMusic 31st December 2010 10:30 AM

from playing with horns before, I don't expect any room gain, but I do expect it to lower the frequency response slightly.

I had modelled a simple, single fold 240cm horn, with eight woofers in it...

one thing I noticed though, was that if I doubled all the "S" figures, and the number of woofers, hornresp suggested that the frequency response would change, and it would play lower...

is this correct?

mashaffer 31st December 2010 04:46 PM

Odd that a driver intended to be used below 1.5K Hz would have a phase plug.

Brian Steele 31st December 2010 09:09 PM

What brand/model are those drivers, and how much did they cost?


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