AK Design Collaborative - Insubnia
- Thread starter Zilch
- Start date
My graphs are not as smooth as maxmercy's cause I did not bother to chase the birds away or worry about the cars driving by.....
Measured 1W 1M SPL is blue, modeled is red.
We measured outdoors over a driveway, so this was not a perfect 2pi measurement by any means. Ambient noise was ~50 dB, so >25 dB down from the measurement levels. We were also probably talking/drinking during the measurements too (much more fun that way!).
This measurement is certainly adequate to verify the performance of the design. We are essentially flat (+/- 3 dB) from 25 Hz to 100 Hz. 2.83 V yields about 86 dB at 1M, which is very close to the prediction.
Drive voltage from amplifier was set at 2.83V into an 8-ohm resistor with my most accurate voltmeter. My equipment is probably accurate to a dB, and should be flat within the area I have presented. Measurements were made with REW using the equipment I have described elsewhere.
I also did a little experiment with HolmImpulse.
Measured SPL and THD:
2nd Harmonic:
3rd Harmonic:
Hmmm, it is a 25 Hz tapped horn design and the THD takes over below that, pretty much as I expected, and exactly as theory predicts. I did not bother with the higher harmonics - they were buried in the noise.
I could have probably increased the drive levels a touch for the HolmImpulse sweeps, but as we were already working well past sunset, I figured measuring at 100+ dB might have upset Todd's neighbors.
The project came out great!
The 50dB ambient noise probably made the THD numbers worse than they really are...are you planning on doing any indoor THD measurements? I would be very interested in those....
JSS
donprice
Wound up workin' at a gas station....
How sensative is the model to the external dimension ratios? My thought is using a pair of them as stands for the main (Indignias?) speakers. Wider but less depth might make a better speaker stand. This is not a criticism of the current design....just a random thought regarding something that I probably wouldn't build (assuming I can repress the urge to build stuff I don't need).
Any ideas for the Mother of Insubnia? Something big enough to stack an eWaved PE trap cab on top of. Yeah, more cool ideas for stuff I don't need.
Any ideas for the Mother of Insubnia? Something big enough to stack an eWaved PE trap cab on top of. Yeah, more cool ideas for stuff I don't need.
Turn it on its side and put the exit hole where it is needed (bottom or side). That makes it ~20" tall, which gets the tweeters closer to 30".
Simulating a driver in a tapped horn is not at all hard to do. Making that tapped horn something that is realistic enough to warrant sawdust is a bit harder, as there has to either be a leap of faith or some experience there. Folding what you simulated up into a complicated fold like the tapped version of the insubnia is where the true kung-fu lies. I spent a lot of time getting the fold done, and to be honest - it is not quite true to the model, but it is clearly close enough.
Simulating a driver in a tapped horn is not at all hard to do. Making that tapped horn something that is realistic enough to warrant sawdust is a bit harder, as there has to either be a leap of faith or some experience there. Folding what you simulated up into a complicated fold like the tapped version of the insubnia is where the true kung-fu lies. I spent a lot of time getting the fold done, and to be honest - it is not quite true to the model, but it is clearly close enough.
I know, but I wanted to paint a real picture, not a pretty one, and I did not want to piss off Todd's neighbors any more than we already had by cranking up the measurement levels.
We'd have measured more, but we honestly ran out of time. I left at 1:30 AM or so (and I had to lecture the following morning...). Todd should be set up to do measurements like me pretty quickly, just needs to source a few parts (meter and sound card). He's building three more Insubnias this week.
Now you've done it....someone opened up another can of worms, and this one isn't even done yet.
Seriously -any thoughts on this?
SPL?
Response?
Power handling?
Cabinet Size?
This will be another one I'd like to play with...
The main factor for the MoI would be size. If you can spare the space, damned near anything is possible....I am working on an 8", 20Hz version of Insubnia, and possibly a 10" sub-20Hz Insubnia. Both will be bigger than the 30Hz and 25Hz Insubnias already posted.....but hopefully small enough to be spread throughout a room to even out response, maybe even wall-mounted....
I'll update as I progress....don't hold your breath, though...
JSS
I'll update as I progress....don't hold your breath, though...
JSS
http://www.avsforum.com/avs-vb/showthread.php?p=18430148#post18430148
The Karma Indignia Theater consists of these modules:
Karma Indignia (mains)
Mindignia (surrounds)
Incentria (center)
Insubnia (subwoofer)
Anybody can build 'em from standard components, mixing and matching as desired:
Computer speakers? Mindignias and Insubnia.
Dorm room? Indignias, Insubnia optional.
On the road? Mindignia pair.
Kitchen or Bedroom? Indignia pair.
Office system? Indignias and Insubnia.
Bedroom HT? Add Incentria.
Apartment HT? The works w/2 Insubnias.
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skywave-rider
Slumming in Akihabara
Is anybody making a knock-down Insubnia kit?
http://www.avsforum.com/avs-vb/showthread.php?p=18430148#post18430148
The Karma Indignia Theater consists of these modules:
Karma Indignia (mains)
Mindignia (surrounds)
Incentria (center)
Insubnia (subwoofer)
Anybody can build 'em from standard components, mixing and matching as desired:
Computer speakers? Mindignias and Insubnia.
Dorm room? Indignias, Insubnia optional.
On the road? Mindignia pair.
Kitchen or Bedroom? Indignia pair.
Office system? Indignias and Insubnia.
Bedroom HT? Add Incentria.
Apartment HT? The works w/2 Insubnias.
marantzfan
...
Those would sure look purty in Piano Black to Match the PE Indignia cabinets... 
Tiver
Enjoy the music
The thought has crossed my mind so long as the originators don't object.
I need to review the cut list and see what kind of effort will be involved.
20 sets of knock downs is probably only four times the effort of one set, so the idea is valid. More would be OK too.
I would want two or four for myself. Need a little time to think about it.
TC Epic 10" is expensive. For the Tangband W8-740P, you can make a box that is less than 50% the size of the TC Epic, but less extension and output:
1W/1m, 2pi space:
corner loaded:
4 of them corner loaded:
The box is 120L in hornresp. You can buy 4 W8-740s for about the same price as one TC EPIC 10". The smaller box loses ~3dB to the larger box, and the TC driver has almost twice the Xmax......but both will do 20Hz (the EPIC will go lower), and the W8 should have no problem doing 10dB below reference, the EPIC should be able to reach referemce with it's Xmax advantage.
I have not experimented with tapped configs yet....
JSS
1W/1m, 2pi space:
corner loaded:
4 of them corner loaded:
The box is 120L in hornresp. You can buy 4 W8-740s for about the same price as one TC EPIC 10". The smaller box loses ~3dB to the larger box, and the TC driver has almost twice the Xmax......but both will do 20Hz (the EPIC will go lower), and the W8 should have no problem doing 10dB below reference, the EPIC should be able to reach referemce with it's Xmax advantage.
I have not experimented with tapped configs yet....
JSS
Attachments
You want four. Corner-loaded. Trust me.
1 is nice, 2 is impressive, 4 is nuts.
I have no problem at all with a precut flat pack.
Unlike some other designs, there are very few "cut-to-fit" pieces, as the horn parts interlock rather than connect in a continuous flare. I cut to the lengths on the sketchup sheet and it all fit together as it should have. If you've accounted for the material thickness properly, things should be fine.
This design is in the public domain for anyone to build and enjoy.
As long as the plans are followed accurately, the results should be predictable.
westend
Audiopile
Thanks for posting this.
I asked about different mouth flares because my experience with folded horns has shown me the type of improvement that can be had using a mouth that is more open. That experience may relate to this design and may be totally irrelevant. I would have to build and compare a few models to exact any improvement. Because of your excellent documentation, it can be done. Thanks, again, for your efforts.:thmbsp: