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Tapped Horn Build pics

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Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=9306
Printed Date: 28 March 2024 at 10:33pm
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Topic: Tapped Horn Build pics
Posted By: tommysb
Subject: Tapped Horn Build pics
Date Posted: 30 March 2007 at 3:07pm
Started building my tapped horn design prototype, I hope it works!

Anyway, here's some pictures of the magic!


The internal Layout



The curved section at the far end of the horn


Before being glued


From Behind


Preparing the bendy MDF!


About half the clamps in place


I accidentally over tighened the rachet straps and cracked the top left corner But it think that's going to be cut off when i assemble the speaker


More of the same!


Going together nicely!





That's it for now!

There was some more work done after these....Cutting the baffle, but made a bit of an error and the rebate to locate the driver in was cut too deep...... I've filled it with wood glue and mdf dust.... I hope it works!

Next installment tomorrow hopefully!





Replies:
Posted By: mykey
Date Posted: 31 March 2007 at 3:15am
nice

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......just all them hanging there like giant bananas.



Posted By: tommysb
Date Posted: 02 April 2007 at 2:56pm
Edit: Double post woops!



Posted By: tommysb
Date Posted: 02 April 2007 at 2:58pm
Worked on it again today.

Filling the too deep rebate with PVA and sawdust worked a charm,




After a rebate had been routered in:



The driver next to it:


Unfortunately, my good router is too big to cut 10" holes, so when cutting the actual hole for the driver, i used my £20 router and it's not as accurate, so the hole is 5mm too big, Grrr!



Here's the curved section without the clamps etc.



It was quite a hassle making it fit, I forgot to account for the thickness off the material when doing the inner curve, so had to make some approximations, and trim it down a bit!

Here it is trimmed:


And the rebate cut for it:


I didn't realise the bendy ply is 2ft wide, rather than 60cm, so might have to change the depth of the cut a bit so all the internals are level for the last panel. Grrrrr!

At least it fits in the rebate well:



Here's some mock-ups of roughly what it should be like when it's done:





You get the idea!

Maybe will finish it tomorrow......We'll see!

Peace out y'all!



Posted By: login4
Date Posted: 02 April 2007 at 4:52pm
fair play that should sound really nice, 

what are the drivers your using?


-------------
CELTIC SUBSONIC SOUND SYSTEMS


Posted By: philpope
Date Posted: 02 April 2007 at 5:34pm
will be interesting to see results. I remain sceptical about tapping in so close to closed end of horn but I hope you prove me wrong and it works fine.
 
Phil


Posted By: tommysb
Date Posted: 03 April 2007 at 7:44pm
The drivers are an autosound called Mivoc 104 I think.

Some more pics. No comments this time, it's late. Except that late speaker building and good speaker building don't go well together!

Peace

















Will test it tomorrow when the glue's definately set.


Posted By: Insomnia
Date Posted: 03 April 2007 at 9:02pm
looking good mate-
 
thanks for sharing the pics with us


Posted By: _djk_
Date Posted: 03 April 2007 at 9:55pm
Looks like a lot of work on the curved surface that will not make a measurable difference in performance.

-------------
djk


Posted By: bitcore
Date Posted: 04 April 2007 at 2:23am
Originally posted by _djk_ _djk_ wrote:

Looks like a lot of work on the curved surface that will not make a measurable difference in performance.

I think it's nice, I like how this is turning out.  He's probably doing better with the wood than I would have.
now lets see some measurements!


Posted By: tommysb
Date Posted: 05 April 2007 at 12:35pm
Originally posted by _djk_ _djk_ wrote:

Looks like a lot of work on the curved surface that will not make a measurable difference in performance.


Yes my thoughts actually! 2 sheets of bendyMDF = £14, which isn't insignificant on a budget build!

Fired it up today, and it's a little dissapointing. Not as sensitive as the big folded horns i have, and not as 'full' sounding.

This was designed to be run as a pair though, so the plan at the moment is to knock together another one real quick, without the rebates or curved section, as I already have most of the panels cut for it, should be possible in about a day. Will have a listen with a sine sweep later and try to judge how peaky the response is, and where cuttoff occurs.

I hope it's not all been in vain!




Posted By: philpope
Date Posted: 05 April 2007 at 1:11pm
try some different drivers. I have managed a 38Hz cutoff with a 98dB driver. with an 88dB driver you would want a tapped horn about twice the length of the one you have made and be aiming for 20dB cutoff. you are never going to get as much gain with a tapped horn but because it controls the excursion better you can use a more sensitive driver with lower xmax.
 
Phil


Posted By: MarjanM
Date Posted: 26 May 2007 at 8:01pm
What happened with this project?
 
Any results to share?


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: _djk_
Date Posted: 27 May 2007 at 12:28pm
These are best simulated in AkAbak (free for personal use).
 
Here are the scripts for a simplified model:
 

| 40Hz Tapped Horn

Def_Const |Horn Dimensions

{
a1 = 500e-4; |Area at throat (cm^2)
a2 = 881e-4; |Area at rear of driver (cm^2)
a3 = 3100e-4; |Area at front of driver (cm^2)
a4 = 3200e-4; |Area at mouth (cm^2)
l1 = 20e-2; |Distance from throat to rear of driver (cm)
l2 = 250e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 10e-2; |Distance from front of driver to mouth (cm)
}

Def_Driver 'Dr1'

| Eminence 3015LF

Sd=881cm2
fs=42Hz
Qes=0.41
Qms=6.82
Vas=160L
Re=5.31ohm
Le=0.92mH

system 'S1'

Driver Def='Dr1' Node=1=0=3=4
Waveguide 'W1' Node=2=3 STh={a1} SMo={a2} Len={l1} Conical
Waveguide 'W2' Node=3=4 STh={a2} SMo={a3} Len={l2} Conical
Horn 'H1' Node=4 STh={a3} SMo={a4} Len={l3} Conical


And here is the sim:
 
 
 About 3dB down at 35hz with only one cabinet, about 103dB at 40hz. $89 9lb neo Eminence driver. Box is about 36X36X24 (SL-36 Cerwin Vega size). Similar to the Danley TH115.


-------------
djk


Posted By: MarjanM
Date Posted: 27 May 2007 at 8:04pm
Any drawing of it?

-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: tommysb
Date Posted: 27 May 2007 at 8:57pm
Sorry Marjan, I never got to take measurements etc. It was designed for use in pairs, I got one built, it didn't sound too great. Never got the second one finished before going back to university. It'll be done in about a month I think though, I'll let you know then!

Peace,
Tom


Posted By: _djk_
Date Posted: 29 May 2007 at 8:07am
"Any drawing of it? "
 
Maybe when I get my scanner figured out.
 
Just got a new computer and nothing worked the same.


-------------
djk


Posted By: DJ Vencenzo
Date Posted: 06 June 2007 at 6:21pm
Originally posted by tommysb tommysb wrote:

Sorry Marjan, I never got to take measurements etc. It was designed for use in pairs, I got one built, it didn't sound too great. Never got the second one finished before going back to university. It'll be done in about a month I think though, I'll let you know then!

Peace,
Tom
 
 
 
that sucks...they look beautiful..i really thought they were gonna sound awesome


Posted By: tommysb
Date Posted: 06 June 2007 at 11:35pm
I'd hardly describe them as beautiful!


Posted By: DJ Vencenzo
Date Posted: 07 June 2007 at 6:28am
Originally posted by tommysb tommysb wrote:

I'd hardly describe them as beautiful!
 
 
i think they do for these reasons..
 
1. you routered/recessed the joints
2. your curved your folds
3. its a tapped horn...radical new design that we are all so very close to figuring out


Posted By: mykey
Date Posted: 07 June 2007 at 8:08am
Originally posted by tommysb tommysb wrote:

I'd hardly describe them as beautiful!
mite have something to do with the words used...curves and horn

-------------
......just all them hanging there like giant bananas.



Posted By: tommysb
Date Posted: 07 June 2007 at 12:17pm
Hahha!

I've done some more modelling of this using the AkAbak model, actually looks like I got it way off, I've written a whole webpage about it, just gotta upload it somewhere!


Posted By: tommysb
Date Posted: 07 June 2007 at 5:18pm
Ok here's my discussion of the horns so far! None of the other links on the page work as of yet, a work in progress they say!

Any comments greatly recieved!
http://www.lsdm.co.uk/doggspace/tappedhorns.html - http://www.lsdm.co.uk/doggspace/tappedhorns.html


Posted By: DJ Vencenzo
Date Posted: 07 June 2007 at 5:57pm
Originally posted by tommysb tommysb wrote:

Ok here's my discussion of the horns so far! None of the other links on the page work as of yet, a work in progress they say!

Any comments greatly recieved!
http://www.lsdm.co.uk/doggspace/tappedhorns.html - http://www.lsdm.co.uk/doggspace/tappedhorns.html
 
 
dam thnaks bro!


Posted By: nightline
Date Posted: 10 June 2007 at 10:14am
I think that the engine of your driver is to weak! I've build a prototype tapped horn with a 12" woofer with 28 N/A strong engine.
The outer demensions of the enclosure are 50x60x70 cm.
The encosure is desiged for an f3 of 48 Hz, and powered with one channel of a QSC PLX3002 the output is awesome!!
I've done an A-B test between the prototype and 2x 18" AudienceDelight B24 subs on a QSC PL6.0II.
The prototype was far winning from the B24 subs!!
 
So try a speaker with a strong engine, at the freq. which both sides of the driver are full working, you got half the engine power on a side of the driver. So in my case 14N/A a side!!
 
Jack


Posted By: _djk_
Date Posted: 10 June 2007 at 2:45pm
The Fs of the chosen driver is way too low for proper tapped horn use.
 
Danley recommends the Fs be a half octave above the Fc of the horn (a 70hz driver for a 50hz horn).


-------------
djk


Posted By: tommysb
Date Posted: 10 June 2007 at 6:21pm
cool thanks for that!


Posted By: _djk_
Date Posted: 11 June 2007 at 1:17am
Here is a script I dashed off in about five minutes for a pair of Eminence DELTALITE® II 2510 (a P-Audio WN-10S is almost identical).
 
Def_Const |Horn Dimensions
{
a1 = 500e-4; |Area at throat (cm^2)
a2 = 700e-4; |Area at rear of driver (cm^2)
a3 = 3100e-4; |Area at front of driver (cm^2)
a4 = 3200e-4; |Area at mouth (cm^2)
l1 = 20e-2; |Distance from throat to rear of driver (cm)
l2 = 180e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 10e-2; |Distance from front of driver to mouth (cm)
}
Def_Driver 'Dr1'
| Eminence 2510ii
Sd=700cm2
fs=53Hz
Qes=0.45
Qms=5.76
Vas=105L
Re=2.53ohm
Le=0.2mH
system 'S1'
Driver Def='Dr1' Node=1=0=3=4
Waveguide 'W1' Node=2=3 STh={a1} SMo={a2} Len={l1} Conical
Waveguide 'W2' Node=3=4 STh={a2} SMo={a3} Len={l2} Conical
Horn 'H1' Node=4 STh={a3} SMo={a4} Len={l3} Conical
 
It's 105dB in the 50hz~60hz region (with 1W, 2V at 4 ohms), and ±2dB from 48hz~150hz (2Pi). I think the Eminence pair would handle 500W/4R rated amp on program material.
 


-------------
djk


Posted By: tommysb
Date Posted: 11 June 2007 at 12:29pm
Have you looked at the excursion at about 250w? I've found the AkAbak model gives a high excursion (10mm+) and it appears to be the same with this model. (outside xmax, though within XMech)

Danley's whitepaper comments on the effectiveness of the tapped horn at controlling excursion.

Is it just a parameter the model is not very good at predicting, or would you realistically expect that sort of excursion?

Cheers,
Tom


Posted By: _djk_
Date Posted: 12 June 2007 at 4:40am
It looks bad on sine waves, but it may be OK for program.
 
If It was me, I would slap another piece of ply over the two 10" holes and stuff a big x-max 15" in it.


-------------
djk


Posted By: tommysb
Date Posted: 07 August 2007 at 7:40pm
Had a play with a pair of these today, bit of eq at 60Hz, and I was pleasantly suprised! Considering the cost of the drivers, it's a viable suicide rig option, will try and take some measurements tomorrow, but it's sounding alright so far!


Posted By: tommysb
Date Posted: 09 August 2007 at 7:37pm


Here's a response plot taken with an ECM8000 about a meter away, no idea of the power going in or anything, but it shows there's a 10db dip at 60Hz. It sounds alright with the 60hz slider all the way up on my graphic.

Any thoughts?

EDIT: Stuck pink noise through a pair of these and recorded it into cubase, then used spectral analysis in sound forge. Guessed best settings etc for the analysis.


Posted By: davey t
Date Posted: 09 August 2007 at 8:41pm
That response looks typical of a tapped horn not configured properly. You get a big dip in the middle and two peaks either side. The dip went away with mine when i put in the correct driver etc. 



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