Tapped Horn for the Lazy and Impatient

[Brian Steele]

I had already bought plans for an Autotuba and even started building it. I'm changing directions, no way the AT would play this low and loud.

Let me play "Devil's Advocate" hear for a second.

Before committing this design to wood, compare it first to a similarly-sized sealed box loaded with a suitable driver or drivers.

For example, if this box works out to be about 1 cu.ft. net, compare it to a sealed 1 cu.ft. net box loaded with a good 12" driver like the Alpine Type R 12D2.

Tapped horns in cars can be nice, but space usually comes at a premium, good drivers are easy to buy and power these days is cheap, which leans the advantage towards basic sealed designs using the most Vd (driver diameter * excursion potential * number of drivers) you are prepared to buy. And these sealed designs will be capable of producing in-car bass in the single-digit frequency range, which no realistic vented or TH system will be able to do.

 

[Jwsewell]

I will take your advice and run the simulation before I commit to anything.

I will add that this project is an exercise in using what equipment I already have and learning new things.

My current sub is an isobaric pair of 12's in .75 ft3 sealed in a blowthrough. (The blowthrough was already cut for a previous Bandpass enclosure, so no I didn't cut a blowthrough for it. LOL)

The 12's are NVX, (sonicelectronics house brand), and the published T/S parameters are incompete making simulations difficult until I get my hands on a woofer tester.

I have been trying to study your folding spreadsheet but Im still fumbling around in HR snd sketchup.
So Ill ask you because I know you know,.....

Is my understanding of un-folding the last fold of the Insubnia correct?

 

[Jwsewell]

Let me play "Devil's Advocate" hear for a second.

Before committing this design to wood, compare it first to a similarly-sized sealed box loaded with a suitable driver or drivers.

For example, if this box works out to be about 1 cu.ft. net, compare it to a sealed 1 cu.ft. net box loaded with a good 12" driver like the Alpine Type R 12D2.

Tapped horns in cars can be nice, but space usually comes at a premium, good drivers are easy to buy and power these days is cheap, which leans the advantage towards basic sealed designs using the most Vd (driver diameter * excursion potential * number of drivers) you are prepared to buy. And these sealed designs will be capable of producing in-car bass in the single-digit frequency range, which no realistic vented or TH system will be able to do.

I compared the sims of a single 8" Insubnia with one of my RF woofers and 200W against a single Alpine SWR12D2 in 1 ft3 sealed with 500W.

The Alpine gives up 7 dB to the 8" Insubnia at 30 Hz until the Alpine matches the output of the TH at 55 Hz

This was all calculated at 2Pi


If I am correct with my simulations I want the Tapped Horn without a doubt.
I already have the pair of 8" subs and more than 400W on tap at 2 ohms and really don't care if the enclosure for two 8's in rather LARGE!
I have plenty of space,(free), and not alot of $$$ to spend on the project.

Hoffman's Iron Law! Works in my favor in this instance!!

 

[Jwsewell]

It would take 3 of the Alpine SWR12d2 in 3 ft3 sealed and 1500W @ 1.3 ohms to best one 8" Insubnia with a single RFP2408 and 200W @ 3.7 ohms by 2 dB at 30 Hz in 2pi


And I still wouldn't get the rising low end response from the sealed Alpines that I would from the TH

Someone please correct me if I am messing this up. LOL!!

Oh and how do I get HR text files posted on here. Heck how about how to post the input screens and plots like y'all do for that matter.

Thanks again to everyone for the help.

I have that feeling I used to get as a kid when I discovered something new or really cool!

 

[Jwsewell]

It would take 3 of the Alpine SWR12d2 in 3 ft3 sealed,(4.00 ft3 gross),and 1500W @ 1.3 ohms to best one 8" Insubnia with a single RFP2408,(3.319 ft3 gross), and 200W @ 3.7 ohms by 2 dB at 30 Hz in 2pi

Hell the Alpines will take up more room.......
And I still wouldn't get the rising low end response from the sealed Alpines that I would from the TH

Someone please correct me if I am messing this up. LOL!!

Oh and how do I get HR text files posted on here. Heck how about how to post the input screens and plots like y'all do for that matter.

Thanks again to everyone for the help.

I have that feeling I used to get as a kid when I discovered something new or really cool!

 

[littlemike]

It would take 3 of the Alpine SWR12d2 in 3 ft3 sealed and 1500W @ 1.3 ohms to best one 8" Insubnia with a single RFP2408 and 200W @ 3.7 ohms by 2 dB at 30 Hz in 2pi


And I still wouldn't get the rising low end response from the sealed Alpines that I would from the TH

Someone please correct me if I am messing this up. LOL!!

Oh and how do I get HR text files posted on here. Heck how about how to post the input screens and plots like y'all do for that matter.

Thanks again to everyone for the help.

I have that feeling I used to get as a kid when I discovered something new or really cool!

Cool project. Nice to see people take this further. I never had the chance to put the Insubnia into a car (or truck), don't have systems in anything currently.

If you want to post a HornResp file, you can export the record, which will save the pertinent bits of the model as a text file. You can either attach the file for others to download, or you can cut and paste the contents into a post.

Here's the Insubnia model (where this all started..):

++++
ID=39.00
Ang=2.0 x Pi
Eg=2.83
Rg=0.00
Fta=0.57
S1=55.98
S2=60.03
Par=8.89
F12=0.00
S2=60.03
S3=218.21
Par=305.91
F23=0.00
S3=218.21
S4=249.70
Par=56.49
F34=0.00
S4=0.00
S5=0.00
L45=0.00
F45=0.00
Sd=131.00
Bl=10.86
Cms=3.93E-04
Rms=1.39
Mmd=29.86
Le=0.84
Re=6.40
TH=1
Vrc=0.00
Lrc=0.00
Ap1=0.00
Lp=0.00
Vtc=337.00
Atc=180.00
Pmax=100
Xmax=5.0
Path=0.0
Fr1=0.00
Fr2=0.00
Fr3=0.00
Fr4=0.00
Tal1=100
Tal2=100
Tal3=100
Tal4=100
Comment=Actual fold Insubnia Anarchy
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FILTER
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0 0 0 0
0.50.50.50.5
0.50.50.50.5
SSSS
1111
1111
2222
1111
111
000
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[Jwsewell]

I figured out how to post the HR text files with a lil' help from littlemike.

Here is the text file for 3 Alpine SWR12D2 in 3 ft3 sealed with 1500W @ 1.3 ohms (about 4 ft3 gross)
View attachment 3sealedswr12d2.txt

And here is the text file for a single 8" RFP2408 in a modified,(by Patrick Bateman), Insubnia ( about 3.2 ft3 gross)
View attachment single8insubnia.txt

 

[Brian Steele]

Recheck some of those inputs for the Alpines - something doesn't seem right. Look at what HornResp says is the Qes - should be 0.47.

In HornResp, I'm getting 110dB @ 40 Hz out of one Alpine 12D2 driver in a <1 cu.ft. box driven with about 1kW, without it hitting its Xmax ratings.

A 2 cu.ft. box with 2 of them driven with 1kW each should add 6dB to that.

Do a 3 cu.ft. net "TL" with one 12D2 and you're easily getting 120dB all the way down to below 30 Hz.

 

[Jwsewell]

Recheck some of those inputs for the Alpines - something doesn't seem right. Look at what HornResp says is the Qes - should be 0.47.

In HornResp, I'm getting 110dB @ 40 Hz out of one Alpine 12D2 driver in a <1 cu.ft. box driven with about 1kW, without it hitting its Xmax ratings.

A 2 cu.ft. box with 2 of them driven with 1kW each should add 6dB to that.

Do a 3 cu.ft. net "TL" with one 12D2 and you're easily getting 120dB all the way down to below 30 Hz.

I double checked and I do have Qes as .47

I get 111dB @ 40 Hz in 1 ft3 with 1000W @ 3.9 ohms and falls to 108dB with 500W...... hmmmm

I was running my sims with 500W each on the Alpines.



If I had the disposable funds I would try a pair of 12 inch type R's in that TL you are suggesting with however much they could take. LOL

 

[littlemike]

I double checked and I do have Qes as .47

I get 111dB @ 40 Hz in 1 ft3 with 1000W @ 3.9 ohms and falls to 108dB with 500W...... hmmmm

I was running my sims with 500W each on the Alpines.



If I had the disposable funds I would try a pair of 12 inch type R's in that TL you are suggesting with however much they could take. LOL

Took a glance at both, the driver specs and files look right to me.

The SWR12D2 is a pretty potent beast. I designed a LARGE TH that used a pair of them for a buddy of mine. We ran them on an EP4000 each, about 1KW/driver. Good fun. They do like a large cabinet and a low tune.

 

[Jwsewell]

I humbly present the "HORNy Snork". Lol



I'm still working on this,(interior folds are not complte), and may shorten the "Snorkle" some. I might even flare it more, Ill play around in Hornresp some more.

Keep in mind that the plan is for two of these enclosures side by side with the mouths coupled.

 

[Jwsewell]

Just in case you are wondering what a Snork is....



Lol

 

[Jwsewell]

Some more progress. Learning on the fly somewhat.....



I having trouble punching my sub hole thru and my lower panel is hollow.... Lol!


I have to give credit,or blame, to jbell for planting the idea in my head. LOL!
http://www.diyaudio.com/forums/subwoofers/167461-mcm-8-dual-tapped-horn-plan.html

 

[kees52]

Hi There

I have some questions, how to implement the output from hornresp drawn if the speaker is halfway out as on picture, and what if it is just in it, or fuirther in it like the tapped horn pic who i think is right done, half out like on TQWT is not complete clear for me..

I have always did think how to do this right for the TQWT, I did drawn the tapped horn, I need some advise from experts here.

thanks,.

 

[Jwsewell]

Hi There

I have some questions, how to implement the output from hornresp drawn if the speaker is halfway out as on picture, and what if it is just in it, or fuirther in it like the tapped horn pic who i think is right done, half out like on TQWT is not complete clear for me..

I have always did think how to do this right for the TQWT, I did drawn the tapped horn, I need some advise from experts here.

thanks,.

I'm far from an expert, not 100% sure what you are asking and I am terrible at explaining things. Lol.....

But I think what your wanting to know is explained in these two diagrams I found on a Google search.
They sure did help me understand.



An Unfolded tapped horn is below. NOTE: a tapped horn must have at least one fold to function.

 

[kees52]

I'm far from an expert, not 100% sure what you are asking and I am terrible at explaining things. Lol...

I mean in hornresp you see the speaker is out for the half part on on pic two and pic one is oke I do now what to do see previous post.

it boring me I am not shure what it means as the speaker puts out of the horn as in pic two as example.

I can also ask on hornresp threat.

regards

 

[Jwsewell]

If I could speak dutch I know we could figure it out.

 

[just a guy]

An externally hosted image should be here but it was not working when we last tested it.

There, now your front tap is firing into the throat and your driver extends past the mouth of the horn on the rear tap as your sim shows. (I showed an expanding csa instead of a constant csa though.) The sides of the mouth would also have to be trimmed back so it would look like this with the side on.

An externally hosted image should be here but it was not working when we last tested it.

This would be an oddity and unless you have a VERY specific reason for doing this it would probably be best to modify the sim to get the driver back fully inside the mouth. As it is it looks dumb and there's no protection for the outside half of the driver on 4 sides.

 

[kees52]

If I could speak dutch I know we could figure it out.

What do block you to learn

 

[kees52]

An externally hosted image should be here but it was not working when we last tested it.

This would be an oddity and unless you have a VERY specific reason for doing this it would probably be best to modify the sim to get the driver back fully inside the mouth. As it is it looks dumb and there's no protection for the outside half of the driver on 4 sides.[/QUOTE]


You got meeee hahaha, this is just what did trouble me, because it is now clear thanks to you that I was right on the first hand, just keeping things inside, otherwise it get stealed.

Hihihi when blow up the woofer the half conus is launged, and the other half is still in the frame, inclusive half the voice coil, what a joke will dat be banging mister murphy of his trone.

Then I did right, see pictures.

thank you mate.

kees