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Old 3rd January 2014, 11:47 AM   #1
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Default Proof of concept design help

Hey guys, I was looking to test the waters of horn design with something cheap and locally available. Been looking at the Re audio rex 8 dvc. Been dabbling in hornresp for a while, not too sure what to make of the results coming from winisd, i know dips are theoretical to a perfect enclosure and the combined graph isn't too much different. Was wondering if anyone could mock up something workable with it, trying to get down low and fairly loud in contrast to a reflex. Simple offset folded tapped horn was where i was going.(i think)


Electrical Q Value -Qes: 0.38
Mechanical Q Value -Qms: 4.21
Total Speaker Q Value -Qts: 0.34
Free Air Resonance -Fs: 22.8 Hz
Equivalent Compliance -Vas: 27.1 liters
One-Way, Linear Excursion -Xmax: 12 mm
Efficiency -SPL 1W/1m: 81.2 dB SPL
Effective Piston Area -Sd: 195 cm^2
DC Resistance -Re: 3.2 ohm
Nominal Impedance -Znom: Dual 4 ohm
Thermal Power Handling -Pe: 175 W
Force Factor -Bl: 15.4
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File Type: jpg untitled.JPG (133.5 KB, 170 views)
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Old 4th January 2014, 10:15 PM   #2
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Also, does the driver seems to be feasible for a TH?
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Old 4th January 2014, 11:09 PM   #3
zlast is offline zlast  United States
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Electrical Q Value -Qes: 0.38
Mechanical Q Value -Qms: 4.21
Total Speaker Q Value -Qts: 0.34
Free Air Resonance -Fs: 22.8 Hz
Equivalent Compliance -Vas: 27.1 liters
One-Way, Linear Excursion -Xmax: 12 mm
Efficiency -SPL 1W/1m: 81.2 dB SPL
Effective Piston Area -Sd: 195 cm^2
DC Resistance -Re: 3.2 ohm
Nominal Impedance -Znom: Dual 4 ohm
Thermal Power Handling -Pe: 175 W
Force Factor -Bl: 15.4[/QUOTE]


Your driver has a VERY low efficiency (81 db). If you looking for a efficient subwoofer, use
a driver with a higher sensitivity (more efficient).
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Old 5th January 2014, 03:01 AM   #4
bjorno is offline bjorno  Sweden
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FYI

b
Attached Images
File Type: jpg Re audio rex 8 dvc_OD-ML-TL.JPG (463.7 KB, 132 views)
File Type: jpg Re audio rex 8 dvc_TH.JPG (197.4 KB, 124 views)
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Old 5th January 2014, 03:46 AM   #5
OscarS is offline OscarS  United States
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Quote:
Originally Posted by zlast View Post
Electrical Q Value -Qes: 0.38
Mechanical Q Value -Qms: 4.21
Total Speaker Q Value -Qts: 0.34
Free Air Resonance -Fs: 22.8 Hz
Equivalent Compliance -Vas: 27.1 liters
One-Way, Linear Excursion -Xmax: 12 mm
Efficiency -SPL 1W/1m: 81.2 dB SPL
Effective Piston Area -Sd: 195 cm^2
DC Resistance -Re: 3.2 ohm
Nominal Impedance -Znom: Dual 4 ohm
Thermal Power Handling -Pe: 175 W
Force Factor -Bl: 15.4

Your driver has a VERY low efficiency (81 db). If you looking for a efficient subwoofer, use
a driver with a higher sensitivity (more efficient).[/QUOTE]

without going to a larger cone, the sensitivity can't be increase without giving up deep bass response. With it's low 22hz Fs, the potential of deep bass is what is gained by sacrificing sensitivity [the parameters are inter-related]. It's a triple edged sword when it comes to bass response. You can't just arbitrarily gain sensitivity without giving something up.
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Old 5th January 2014, 04:07 AM   #6
zlast is offline zlast  United States
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Quote:
Originally Posted by OscarS View Post
Your driver has a VERY low efficiency (81 db). If you looking for a efficient subwoofer, use
a driver with a higher sensitivity (more efficient).
without going to a larger cone, the sensitivity can't be increase without giving up deep bass response. With it's low 22hz Fs, the potential of deep bass is what is gained by sacrificing sensitivity [the parameters are inter-related]. It's a triple edged sword when it comes to bass response. You can't just arbitrarily gain sensitivity without giving something up.[/QUOTE]

I do not believe I stated any of the above...and 81 db is VERY low sensitivity. No parameters/specifications or design goals are stated. Perhaps 90 db peek output is ok, maybe not...simply suggesting that depending on his (unstated) goals, there might be better driver choices.
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Old 5th January 2014, 07:16 AM   #7
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Quote:
Originally Posted by bjorno View Post
FYI

b
Hi bjorno,

Do you realise that you have FINALLY posted an input parameters screenprint with the record number shown :-).

4225 records means that you definitely qualify as a Hornresp "Grand Master".

Congratulations!

Kind regards,

David
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Old 5th January 2014, 10:12 AM   #8
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Wow, bjorno, you really went all out, thank you so much.... I'm beginning to see since modelling with hornresp that it's a lot more true to reality and lot more difficult to fine tune .Also didn't know hornresp could model t lines till I stumbled on it by accident. Once the horn became a line, the wizard shifted. I didn't really consider sensitivity too much since horns would improve the overall system but these graphs seem promising. Zlast, its just something to get me used to this new breed of enclosures, heard these woofers in many bass reflex/sealed systems so I know their sound is good. Will give this a go once i get some wood.
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Old 11th January 2014, 12:03 AM   #9
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by David McBean View Post
Hi bjorno,

Do you realise that you have FINALLY posted an input parameters screenprint with the record number shown :-).

4225 records means that you definitely qualify as a Hornresp "Grand Master".

Congratulations!

Kind regards,

David
Thank you David...

Those are the HR Records I have in my Lap-Top and there are probably more in the 3 other PC: s I possess...In total?, I guess the number should be doubled.(I hav'nt tested HR.merge,Yet)

A late DIY Christmas Gift to you all: Recently I played with 'Pillow-Fill' stuffing and Polyester Fiber Batting material like:

Thermal-bonded Polyester Insulation Batts - Buy Wall Polyester Insulation Batts,Polyester Insulation Supplier,Polyester Insulation Batting Product on Alibaba.com

Perfect to be used in TH: s or any other quarter-wave designs where at least ~25% of the Volume that is left non-blocked, thus providing a free air path from the Throat to the Mouth with a low Air-flow Reststance.

...The outcome in pictures, of course(3).

b
Attached Images
File Type: jpg Pillow-Fill_Air-flow-Reststance_Absorption-Coefficient_Impedance.JPG (437.7 KB, 67 views)
File Type: jpg Pillow-Fill_Measurements.JPG (524.6 KB, 68 views)
File Type: jpg Z_AP50_Polyester-Batten.JPG (340.0 KB, 22 views)
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Old 11th January 2014, 01:27 AM   #10
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by meccalli View Post
..Will give this a go once i get some wood.
Hi meccalli,

Watch out for updates before cutting wood! HR updates are soon passing the speed of Moore's law...and don't poke with to many buttons at once and you will be safe.
Good Luck!

b

PS: Found a 'Typo' in my previous posted calculation of Re Audio Rex 8 DVC coils. Corrected in a new Picture:
Attached Images
File Type: jpg Re audio rex 8 dvc_T-TQWT.JPG (473.5 KB, 21 views)
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