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Old 19th July 2007, 04:57 PM   #511
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Default Re: Tapped horns for dummies

Quote:
Originally posted by OzMikeH
What T/S specs make a driver suitable for a tapped horn?
So far, that´s not discovered in full extend. It seems that drivers with a fairly high fs work better, resulting in a smoother frequency response.
Quote:
Is there an ideal "slope" for the interior baffle (expansion rate)?
So far most dedigns use a conical flare function, since it´s most easy to build. Of course, others are possible, too. hornresp and Akabak are capable of doing conical and exponential types. Theoreticaly, Hyperbolic and others should work, too. You can do some tweaking with the frequency response in Akabak and hornresp if you differ flare rate on the first and last segment from flare rate of the main part.
Quote:
Can a tapped horn be designed for a suitable driver without special software or a degree in mathematics?
Well, it´s mostly trial and error so far, but hornresp and Akabak are very useful tools to keep it quite simple.
Quote:
Is building a tapped horn without careful design likely to result in disaster?
Like al transducer cabinets: Just building some random box and putting some random speaker in it mostly results in garbage, same here.
Quote:
What effect does the changing the size of the opening have?
The more area the hornmouth has, the more seinsitivity you gain.
Quote:
Is there any advantage in using multiple smaller (8 inch) drivers?
2 medium (10 inch) drivers? 1 large driver?
My guess is that general rules of picking a speaker for a special application apply here, too. Bigger drivers (and ones with heavy cones) have more difficulties moving fast than small ones. Just like when you compare 2x10" with a 15". on the other side - bigger drivres ususaly are build for subwoofer applications where high excursion rates are common. If you find a small driver with the same xmax-capacity as a big one and use as many small ones to add up Sd to the big driver - you can get it to work (assuming that the overall quality of the compared drivers is the same and the resulting TSP are euiqvalent)
Quote:
Would a more even response be acheived by having 2 different angled baffles and drivers in one cabinet? see the rough sketch, vents out the bottom. Probably feindishly difficult to model. [/B]
You should´t mix two tunings or allignemts in one box, since phase and pressure difference will start interact with each other and mostly cancel each other out.
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Old 19th July 2007, 06:00 PM   #512
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Hi Amit_112dB,

Quote:
hi i had a small querry about horn loaded speakers...
...i think design is nice, external motor will keep driver cool, BUT wont the front n rear wave cansel each other???
Tapped Horns are designed so that the front and rear wave sum to boost the output above the 1/4 wave cutoff. Remember, the two sides of the speaker cone are 180 Deg out to begin with, so delaying the front wave by an additional 180 Deg allows them to sum.

I'm no expert on Tapped Horns, but thankfully Danley, McBean and Cowan are! See Danley's white paper and download Hornresp v16 (a freeware simulation of Tapped Horns).

See:
http://www.danleysoundlabs.com/pdf/danley_tapped.pdf
http://www.users.bigpond.com/dmcbean/
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Old 19th July 2007, 06:15 PM   #513
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Default Thank a lot don

Don

i have downloaded the s/w, will try getting my hands on it tomorrow.

hey, the link you gave is not working, might be because of my office firewall, can you please check 1ce if the link is correct or not?

http://www.danleysoundlabs.com/pdf/danley_tapped.pdf
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Old 19th July 2007, 07:28 PM   #514
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Hi Amit_112dB,

Yep, that's the right URL

Danley's site has been very slow, and PDF's are always slow. Try again later.
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Old 22nd July 2007, 05:06 AM   #515
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Last week I built another tapped horn. This time with a Beyma 12LX60.
Its sounds great! Realy powerfull and dynamic!

Here is som hornresp sims:
Click the image to open in full size.


And a picture of the layout:

Click the image to open in full size.

And a picture of the horn standing in my corner:

Click the image to open in full size.

Thats my 5 year old kid standing next to it.
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Old 22nd July 2007, 05:09 AM   #516
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And the driver in the mouth:

Click the image to open in full size.

When I play realy loud, pushing something like 50 -80 watts into it, the cone barely moves att all. Maybe a mm or so. Its strange putting my finger on the cone. My walls are flexing something like 5 mm but the driver is barely moving!


The horn is 204,5 cm high, 39,4 cm wide and 53 cm deep.

Thats 80,5 x 15,5 x 20,8 inches. It must weight around 100 kg.
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Old 22nd July 2007, 05:27 AM   #517
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Hi Circlomanen,

Good Job!!!

Is that 25mm MDF? Are you adding any bracing? What hi-pass and lo-pass are you using?

Keep up the good work,
~Don
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Old 22nd July 2007, 02:29 PM   #518
freddi is offline freddi  United States
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way cool Circlomanen ! - in USA, Beyma carry relatively high price - some B&C might work

what's the size of this TH and its mouth opening aspect? - is mouth ~square?

(I like Karlson as their cone excursion is low)

B&C 12 TBX100 - 12" HIGH POWER WOOFER

Resonant Frequency (fs) 42 Hz
Impedance (Re) 5.1 ohms
Electrical Factor(Qes) .27
Mechanical Q (Qms) 6.9
Total Q (Qts) .26
Compliance Equiv. Vol. (Vas) 37.5 Liters/1.3cu. ft.
Voice Coil Overhang (Xmax) 9.0mm
Reference Efficiency 1.15%
BL Factor 25.5 T-M
Surface Area of Cone (Sd)m2 0.0823m2
Coil Inductance (Le) 1.6mH


*************

12 PS100 - 12" HIGH POWER WOOFER

Resonant Frequency (fs) 44 Hz
Impedance (Re) 5.3 ohms
Electrical Factor(Qes) .29
Mechanical Q (Qms) 3.9
Total Q (Qts) .27
Compliance Equiv. Vol. (Vas) 47 Liters/1.6cu. ft.
Voice Coil Overhang (Xmax) 8.0mm
Reference Efficiency 1.3%
BL Factor 22.5 T-M
Coil Inductance (Le) 2.0mH
***********************************

12 TBX32 - 12" HIGH POWER WOOFER

Resonant Frequency (fs) 40 Hz
Impedance (Re) 5.3 ohms
Electrical Factor(Qes) .20
Mechanical Q (Qms) 3.11
Total Q (Qts) .19
Compliance Equiv. Vol. (Vas) 66.2 Liters/2.34cu. ft.
Voice Coil Overhang (Xmax) 10.0mm
Reference Efficiency 2.11%
BL Factor 25.7 T-M
Surface Area of Cone (Sd)m2 0.055m2
Coil Inductance (Le) 1.72mH
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Old 22nd July 2007, 06:38 PM   #519
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[CODE]Good Job!!!Good Job!!!

Is that 25mm MDF? Are you adding any bracing? What hi-pass and lo-pass are you using?


Thats 22 mm MDF. I have one brace. From just above he mouth. You can see the screws on the picture with my kid. Thats were i think its needed the most. Stabilizing the baffel and the big front/mouth.

No Highpass at all. Just a 18dB lowpass at 100 Hz. Thats a bit to high. Im going to build a bandpass XO with 24dB slopes at 25 Hz and 80 Hz soon.

It sound VERY clean and powerfull. That scen where Darla tapps with her finger on the glass-tank in Finding Nemo is realy impressing. I have heard it before on powerfull subs but NOTHING like this! Its just soo clean and well defined.

Thank you!

Johannes.
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Old 22nd July 2007, 07:25 PM   #520
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Click the image to open in full size.

This is a picture of the bracing.
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