The Smallest Tapped Horn - Page 8 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 15th May 2009, 08:55 PM   #71
diyAudio Member
 
Join Date: Jul 2008
Location: Pacific Northwest
Odd - the link I posted works for me when I test it.

GM - your link does not work for me in Firefox, but does work in Internet Explorer.

Sorry for the confusion.
  Reply With Quote
Old 15th May 2009, 10:35 PM   #72
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Interesting! I wonder why, especially since I'm running Mozilla Firefox also. Yours I get an error message and of course my link works for me in Firefox, but both mine and yours works in IE. This really makes no sense to me.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 15th May 2009, 11:32 PM   #73
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Here's some pics of the boxes. I noticed in the diagram I forgot to include the height of the mouth! It's sixteen inches tall. The first box is 13.5" wide, the second is 9.5" wide.

The simulation for the P-Audio is based on a width of 12", but then I noticed the frame is 12.25". Shouldn't make a big difference in the response...

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 17th May 2009, 07:36 PM   #74
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Based on a discussion here, I threw together a pic of what this box would sound like if I didn't use a flare at the mouth.

The idea is that using a significant flare at the mouth flattens the response, while raising the F3. Since this box will likely end up in a car, a low F3 is actually a bad thing (due to cabin gain.)

Flatter response and a small box are definitely what we're after here.

Click the image to open in full size.
  Reply With Quote
Old 20th May 2009, 04:39 AM   #75
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
So I'm building two boxes. One for a single twelve, and one for dual eights. Just to cover my bases, I created an Akabak script to model a tapped horn with dual woofers. (Horn response models them as if they're radiating from the same point in space; it doesn't account for the gap between them.)

I was a bit surprised to see that the efficiency nearly doubles, and 3rd harmonic distortion is reduced too!

Talk about a free lunch

Here's a pic of the response; note it's more efficient from 60-150hz, and *less* efficient from 250hz on up (where the distortion is.)

Niiiiiice....

Click the image to open in full size.

The graph looks a little weird because I use a photo editor to merge the two simulations (I don't think there's a way to compare two designs in Akabak or Hornresp.)
  Reply With Quote
Old 20th May 2009, 04:44 AM   #76
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Here's an Akabak model for a tapped horn with dual woofers.
It's a bit confusing; let me know if it's hard to figure out where the taps are. I included a diagram.

System 'S1'

|DATA EXPORTED FROM HORNRESP - RESONANCES NOT MASKED
|COMMENT: th-mini clone, xara file is on other pc, 5/10/09. This one w/MCM 55-2421x2
|================================================= ================================================== =====
|REQUIRED AKABAK SETTINGS:
|File > Preferences > Physical system constants:
|Sound velocity c = 344m/s
|Medium density rho = 1.205kg/m3
|Sum > Acoustic power:
|Frequency range = 10Hz to 20kHz
|Points = 533
|Input voltage = 31.62V rms
|Integration = 2Pi-sr
|Integration steps = 1 degree ... 1 degree
|Integration method = Cross
|================================================= ================================================== =====

Def_Const |Hornresp Input Parameter Values

{
|Length, area and volume values converted to metres, square metres and cubic metres:
Rg = 0.01e-0; |Amplifier output resistance (ohms)
S1 = 54.83e-4; |Horn segment 1 throat area (sq cm)
S2 = 70.00e-4; |Horn segment 1 mouth area and horn segment 2 throat area (sq cm)
S3 = 90.00e-4; |Horn segment 2 mouth area and horn segment 3 throat area (sq cm)
S4 = 387.00e-4; |Horn segment 3 mouth area and horn segment 4 throat area (sq cm)
S5 = 604.40e-4; |Horn segment 4 mouth area and horn segment 5 throat area (sq cm)
S6 = 1401.30e-4; |Horn segment 5 mouth area and horn segment 6 throat area (sq cm)
S7 = 1836.00e-4; |Horn segment 6 mouth area (sq cm)

L12 = 25.64e-2; |Horn segment 1 axial length (cm)
L23 = 30.00e-2; |Horn segment 2 axial length (cm)
L34 = 170.00e-2; |Horn segment 3 axial length (cm)
L45 = 11.00e-2; |Horn segment 4 axial length (cm)
L56 = 40.60e-2; |Horn segment 5 axial length (cm)
L67 = 22.10e-2; |Horn segment 6 axial length (cm)

|Parameter Conversions:

Sd = 440.00e-4; |Total diaphragm area for 2 parallel drivers (sq cm)

}

|================================================= ================================================== =====

|Network node numbers for this tapped horn system:

|0-Voltage-1-Resistance-2----------
| x x
| --Driver1------ ---------------------------
| x -Driver2-------------- x
| x x x x
| 8-Segment-9-Segment-10-Segment-11-Segment-12-Segment-13-Segment-14-Radiator
|================================================= ================================================== =====


Def_Driver 'Driver'

Sd=220.00cm2
Bl=14.56Tm
Cms=3.48E-04m/N
Rms=1.20Ns/m
fs=31.0000Hz |Mmd = 73.86g not recognised by AkAbak, fs calculated and used instead
Le=2.42mH
Re=3.40ohm
ExpoLe=1

System 'System'

Resistor 'Amplifier Rg'
Node=1=2
R={Rg}

Driver Def='Driver''Driver 11'
Node=2=0=9=12
Driver Def='Driver''Driver 21'
Node=2=0=10=13

Waveguide 'Horn segment 1'
Node=8=9
STh={S1}
SMo={S2}
Len={L12}
Conical

Waveguide 'Horn segment 2'
Node=9=10
STh={S2}
SMo={S3}
Len={L23}
Conical

Waveguide 'Horn segment 3'
Node=10=11
STh={S3}
SMo={S4}
Len={L34}
Conical

Waveguide 'Horn segment 4'
Node=11=12
STh={S4}
SMo={S5}
Len={L45}
Conical

Waveguide 'Horn segment 5'
Node=12=13
STh={S5}
SMo={S6}
Len={L56}
Conical

Waveguide 'Horn segment 6'
Node=13=14
STh={S6}
SMo={S7}
Len={L67}
Conical

Radiator 'Horn mouth'
Node=14
SD={S7}
  Reply With Quote
Old 20th May 2009, 06:39 AM   #77
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
I cranked out a model for four woofers, and now the first peak is completely gone! This really widens the bandwidth in a huge way.
  Reply With Quote
Old 20th May 2009, 06:10 PM   #78
diyAudio Member
 
Join Date: Sep 2008
Hmm. You seems to have connected the drivers wrong.

The first driver needs to be first and last.
The second in the middle (as you fold around)
Unless you have some strange folding.

Driver Def='Driver''Driver 11'
Node=2=0=9=12
Driver Def='Driver''Driver 21'
Node=2=0=10=13

vs

Driver Def='Driver''Driver 11'
Node=2=0=9=13
Driver Def='Driver''Driver 21'
Node=2=0=10=12

Might be wrong though.
I can't see much benefit now.
Impulse response is smeared out due to additional peaks from drivers.
Not sure if it matters at LF though.

I will have to do further testing as I just finished my own model.
  Reply With Quote
Old 20th May 2009, 06:57 PM   #79
diyAudio Member
 
MikeHunt79's Avatar
 
Join Date: Aug 2003
Location: Bristol, UK
Quote:
Originally posted by Patrick Bateman
Amplifiers are ridiculously cheap, and it would be fun to have a boomin' system in the car. I cloned an autotuba a few years back and fed it with an 800 watt amp, that was a lot of fun until I got sick of the sheer size of the box.
If you don't mind me asking, what do you have in your car now?

I currently have a dual driver autotuba in mine, and while is sounds great, it is a little large as it fills my entire boot (trunk)!

I was wondering if there is something similar which is smaller yet gives the same rising response of the AT?

I was thinking maybe a TH tuned to 60Hz, maybe with a 8" MCM but maybe a 12" driver would work better?
  Reply With Quote
Old 20th May 2009, 07:15 PM   #80
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally posted by David_Web
Hmm. You seems to have connected the drivers wrong.

The first driver needs to be first and last.
The second in the middle (as you fold around)
Unless you have some strange folding.

Driver Def='Driver''Driver 11'
Node=2=0=9=12
Driver Def='Driver''Driver 21'
Node=2=0=10=13

vs

Driver Def='Driver''Driver 11'
Node=2=0=9=13
Driver Def='Driver''Driver 21'
Node=2=0=10=12

Might be wrong though.
I can't see much benefit now.
Impulse response is smeared out due to additional peaks from drivers.
Not sure if it matters at LF though.

I will have to do further testing as I just finished my own model.
You are correct - I didn't catch this until I made the four woofer model, and the response was really bizarre until I fixed it.

Before I built a tapped horn, I was worried that they'd have issues in the time domain. But I haven't noticed any subjectively. Once you get used to the lack of distortion, sealed subs start to sound kinda weird.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tapped Horn for Dummies Patrick Bateman Subwoofers 249 3rd June 2012 08:10 PM
Tapped Horn For Car mwmkravchenko Subwoofers 365 17th November 2011 10:22 AM
tapped horn wiki? weikertball Subwoofers 0 31st May 2008 05:20 PM


New To Site? Need Help?

All times are GMT. The time now is 02:25 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2