2 heating radiators and a doorway - corners are dead space (unless one has corner speakers already) 😉
attic, basement, or upper wall near ceiling?
I am going to start building one of these this week. I am going to use an Infinity 1262W sub driver. I have simmed this driver in Hornresp on this design and using a 2.0mh inductor the response is basically identical to the Lab 12. I bought 4 of those lnfinities when they were closing them out at $60 each.
I have it mostly built and ready to go. Here are a couple photos. I'll have to post my impressions once I get to listen to it for a while. I am going to use a Behringer DSP1000 to drive it.
Looks awesome! Interested to see how you like it with the infinity driver. I love mine with the lab driver.
I used Hornresp to sim several drivers (including the Infinity) and it looked almost identical in response and extension to the Lab driver. I am using a 13 gauge 2.0mh inductor that I found for a good price.
Lab12-Alpine R-W12D2 Tapped Horn
So I really wanted to build a TH for home theatre to understand what all the hype is about.
My first effort was a Martinsson TPAM10HTL that worked great - ie build matched simmed and benefitted from a big boost down low from room gain. I chose this as I wanted to try out some drivers I already owned.
For ULF output I was drawn to this design but landing the Eminence Lab12 in Aus is about a $400 proposition with shipping. Alpine car subwoofers are available locally however so I instead investigated the Apline SWS-12 or SWR-12 (and newer R-W series) as alternatives.
Neither look as good as the Lab12 when modelled, but my experience with room modes suggested that real world issues would likely overshadow the hornresp bumps.
R-W12D2 in black, Lab12 in grey (specs say 20mm xmax on this new R-W series)
and SWS in black, Lab12 grey...
So after showing this to a buddy who is a HT nut he went straight out and purchased a pair of the Alpine R-W12D2 and I already have a pair or SWS-1242 doing duty in my pool area music system. 😀
Long story short, this system is great!
Here is a comparison of the SWS and R-W12D2 measured ground plane in my driveway with 2 volts....
Here is the R-W12D2 measured in my room at the mouth and at MLP....
Goes to show those resonance peaks in the Hornresp model aren't as large as predicted and that my nasty room mode between 30 and 40hz is a monster by comparison (nothing that a DCX2496 and three other subs in the room can't tame though).
And here is the effect or lowering the test receiver's low pass crossover on the peaks.....
This image shows the measured range - the sweep starts at 10hz in each case, the upper cutoff frequency is set in the Onkyo's low pass setting for the subwoofer. So for example the gold trace is for 10hz to 40 hz.
Some pics of my measurement setup (not super highend but this is how I go about it).....
I shifted the mouth to a different location to that in the original design because this will be used behind the lounge in my buddies HT room.
I measure 2 volts (these are 4 ohms drivers)
Here's my test rig (MazLab 😉 )....
So if Hofman's iron law holds then I've picked all three with this box = large, loud and low!
And the wife was happy when this left the house!
Thats a 100L enclosure with a beer on top with an Alpine SWR-1540 for reference....
So how does it sound? Its big, monumental even.
My neighbour helped me to bring this inside. He's a qualified sound engineer and in previous jobs has installed commercial cinema and worked on big budget movie sound production. His comment was "better be careful your ceilings don't come down on you"! ;-)
I normally run a pair of BR Alpine 15's and a pair of PR 10's which helps with the SPL and to smooth room modes. We ran this on its own and unequalised. It gets very loud and low. The Danley train start was epic.
I'll be installing two of these TH's in my friends HT room. Along with his pair of Alpine SWX-12's and a Dayton Classic 18 we should have some fun!
So I really wanted to build a TH for home theatre to understand what all the hype is about.
My first effort was a Martinsson TPAM10HTL that worked great - ie build matched simmed and benefitted from a big boost down low from room gain. I chose this as I wanted to try out some drivers I already owned.
For ULF output I was drawn to this design but landing the Eminence Lab12 in Aus is about a $400 proposition with shipping. Alpine car subwoofers are available locally however so I instead investigated the Apline SWS-12 or SWR-12 (and newer R-W series) as alternatives.
Neither look as good as the Lab12 when modelled, but my experience with room modes suggested that real world issues would likely overshadow the hornresp bumps.
R-W12D2 in black, Lab12 in grey (specs say 20mm xmax on this new R-W series)
and SWS in black, Lab12 grey...
So after showing this to a buddy who is a HT nut he went straight out and purchased a pair of the Alpine R-W12D2 and I already have a pair or SWS-1242 doing duty in my pool area music system. 😀
Long story short, this system is great!
Here is a comparison of the SWS and R-W12D2 measured ground plane in my driveway with 2 volts....
Here is the R-W12D2 measured in my room at the mouth and at MLP....
Goes to show those resonance peaks in the Hornresp model aren't as large as predicted and that my nasty room mode between 30 and 40hz is a monster by comparison (nothing that a DCX2496 and three other subs in the room can't tame though).
And here is the effect or lowering the test receiver's low pass crossover on the peaks.....
This image shows the measured range - the sweep starts at 10hz in each case, the upper cutoff frequency is set in the Onkyo's low pass setting for the subwoofer. So for example the gold trace is for 10hz to 40 hz.
Some pics of my measurement setup (not super highend but this is how I go about it).....
I shifted the mouth to a different location to that in the original design because this will be used behind the lounge in my buddies HT room.
I measure 2 volts (these are 4 ohms drivers)
Here's my test rig (MazLab 😉 )....
So if Hofman's iron law holds then I've picked all three with this box = large, loud and low!

And the wife was happy when this left the house!
Thats a 100L enclosure with a beer on top with an Alpine SWR-1540 for reference....
So how does it sound? Its big, monumental even.
My neighbour helped me to bring this inside. He's a qualified sound engineer and in previous jobs has installed commercial cinema and worked on big budget movie sound production. His comment was "better be careful your ceilings don't come down on you"! ;-)
I normally run a pair of BR Alpine 15's and a pair of PR 10's which helps with the SPL and to smooth room modes. We ran this on its own and unequalised. It gets very loud and low. The Danley train start was epic.
I'll be installing two of these TH's in my friends HT room. Along with his pair of Alpine SWX-12's and a Dayton Classic 18 we should have some fun!
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Some obligatory build pics....
Thanks heaps to all that made this design possible! 😀
Thanks heaps to all that made this design possible! 😀
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Dead pics - second time around is a treat.....
Neither look as good as the Lab12 when modelled, but my experience with room modes suggested that real world issues would likely overshadow the hornresp bumps.
R-W12D2 in black, Lab12 in grey (specs say 20mm xmax on this new R-W series)
![]()
and SWS in black, Lab12 grey...
![]()
So after showing this to a buddy who is a HT nut he went straight out and purchased a pair of the Alpine R-W12D2 and I already have a pair or SWS-1242 doing duty in my pool area music system. 😀
Long story short, this system is great!
Here is a comparison of the SWS and R-W12D2 measured ground plane in my driveway with 2 volts (cos these are 4 ohms drivers) for a reasonably accurate 1 watt @ 1 meter SPL that seems to be in good agreement with the Hornresp model....
![]()
Here is the R-W12D2 measured in my room at the mouth and at MLP....
![]()
Goes to show those resonance peaks in the Hornresp model aren't as large as predicted in room and that my nasty room mode between 30 and 40hz is a monster by comparison (nothing that a DCX2496 and three other subs in the room can't tame though).
And here is the effect or lowering the test receiver's low pass crossover on the peaks, (measured in my driveway again).....
![]()
This image shows the measured passband range - the sweep starts at 10hz in each case, the upper cutoff frequency is set in the Onkyo's low pass setting for the subwoofer. So for example the gold trace is for 10hz to 40 hz.
Some pics of my measurement setup (not super highend but this is how I go about it).....
![]()
I shifted the mouth to a different location to that in the original design because this will be used behind the lounge in my buddies HT room.
I measure 2 volts (these are 4 ohms drivers)
![]()
Here's my test rig (MazLab 😉 )....
![]()
So if Hofman's iron law holds then I've picked all three with this box = large, loud and low!![]()
And the wife was happy when this left the house!
![]()
Thats a 100L enclosure with a beer on top with an Alpine SWR-1540 for reference....
![]()
So how does it sound? Its big, monumental even.
My neighbour helped me to bring this inside. He's a qualified sound engineer and in previous jobs has installed commercial cinema and worked on big budget movie sound production. His comment was "better be careful your ceilings don't come down on you"! ;-)
I normally run a pair of BR Alpine 15's and a pair of PR 10's which helps with the SPL and to smooth room modes. We ran this on its own and unequalised. It gets very loud and low. The Danley train start was epic.
I'll be installing two of these TH's in my friends HT room. Along with his pair of Alpine SWX-12's and a Dayton Classic 18 we should have some fun!
Attachments
Last edited:
Nice photo shoot!Thanks to Don Snyder & Chris.
![]()
Split off from this long post,
Collaborative Tapped horn project - diyAudio
- 2-sheets of 3/4" 15-ply ApplePly used.
- The blue CAT5 will be used to power some RGB LEDs to illuminate the 1/2" Green-Edge CNC Carving / access panel.
- Coil will be installed later
Here are my current build pictures:
Old Canon 10D, 28-135mm USM-IS, ISO100, F16, 1/80sec.
![]()
![]()
![]()
Some CNC V-Bit Carving Action:
![]()
![]()
Setup took about an hour
![]()
The horn is the star!
One installed, one more to go
This weekend we installed the first of two of these monsters into my buddies HT.
Simply stunning results. I'll be starting the build of a second. Cannot even begin to comprehend what adding a second will do after the step up adding one of these was.
All of what I understood possible with DIY has changed. What I measured does not seem to translate like previous BR builds did in terms of listening experience. Maybe its just the room and location of placement? I really don't know, but whatever is going on here it is stupidly good.
I highly recommend not building one of these if you are satisfied with your system. Now all I can do is think about converting all my BR subs to tapped horns using Brian Steele's tapped horn box folders!
Again, huge thanks to all that made this design possible!
This weekend we installed the first of two of these monsters into my buddies HT.
Simply stunning results. I'll be starting the build of a second. Cannot even begin to comprehend what adding a second will do after the step up adding one of these was.
All of what I understood possible with DIY has changed. What I measured does not seem to translate like previous BR builds did in terms of listening experience. Maybe its just the room and location of placement? I really don't know, but whatever is going on here it is stupidly good.
I highly recommend not building one of these if you are satisfied with your system. Now all I can do is think about converting all my BR subs to tapped horns using Brian Steele's tapped horn box folders!
Again, huge thanks to all that made this design possible!

Attachments
Last edited:
That sim could probably use with a bit of tweaking to make it a bit more accurate.
1. 2*PI instead of 0.5*PI space
2. PAR instead of CON segments
3. Use of semi-inductance parameters for the Type R W12D2, which may make quite a difference to the accuracy of the sim at upper bass frequencies.
4. Cone volume compensation using Vtc and Atc
5. Horn type should be "TH", not "ND"
6. Le is definitely not as high as 8mH, unless you used an inductor in series with the driver.
1. 2*PI instead of 0.5*PI space
2. PAR instead of CON segments
3. Use of semi-inductance parameters for the Type R W12D2, which may make quite a difference to the accuracy of the sim at upper bass frequencies.
4. Cone volume compensation using Vtc and Atc
5. Horn type should be "TH", not "ND"
6. Le is definitely not as high as 8mH, unless you used an inductor in series with the driver.
Attachments
That sim could probably use with a bit of tweaking to make it a bit more accurate.
1. 2*PI instead of 0.5*PI space
2. PAR instead of CON segments
3. Use of semi-inductance parameters for the Type R W12D2, which may make quite a difference to the accuracy of the sim at upper bass frequencies.
4. Cone volume compensation using Vtc and Atc
5. Horn type should be "TH", not "ND"
6. Le is definitely not as high as 8mH, unless you used an inductor in series with the driver.
Hi Brian,
Here is my my input screen used to validate the Alpine R-W12D2 in this enclosure. I think this includes all but the semi-inductance. I do not yet have a DATS or similar that is required to measure this specification, if I'm not mistaken. I also adjusted the Eg to account for the nominal 4ohmn load with voice coils wired in series.
The original design included an inductor to raise Le to smooth the response.
Thanks!
😀
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Works a treat with an Alpine SWR-1241D too!
I picked up a DOA Alpine SWR-1241D.
Figured I'd give it a whirl in my second Snider cabinet build.
Hornresp didn't give me much hope. 😕
Measured in the cabinet it sounds grand! 😀
I picked up a DOA Alpine SWR-1241D.
Figured I'd give it a whirl in my second Snider cabinet build.
Hornresp didn't give me much hope. 😕
Measured in the cabinet it sounds grand! 😀
Attachments
@ Mazza
Hi, the Grey sim looks better, so which did you do ?
I expect that the room & position of the sub changed the response to your liking 😉
Hi, the Grey sim looks better, so which did you do ?
I expect that the room & position of the sub changed the response to your liking 😉
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