AK Design Collaborative - Insubnia
- Thread starter Zilch
- Start date
Actually, it is a touch bigger, but it plays lower, and perhaps a touch louder.
As folded, the cabinet is 30" high, 20" wide, and 8.25" deep.
I'll post plans when I post the measurements. I do not want to waste anyone else's time if it is a bust.
It is a bit bigger than I wanted, but there is zero wasted space, and the driver barely fits. There is close to 1/2 a cubic foot of wood in the horn dividers alone, I folded 13.5 feet of tapped horn into that cabinet.
Only way I could make it smaller is make it shorter, but then it would not play as low.
Driver is your choice - the Exodus Anarchy is preferred, the TB W6-1139 is a possible substitute.
As folded, the cabinet is 30" high, 20" wide, and 8.25" deep.
I'll post plans when I post the measurements. I do not want to waste anyone else's time if it is a bust.
It is a bit bigger than I wanted, but there is zero wasted space, and the driver barely fits. There is close to 1/2 a cubic foot of wood in the horn dividers alone, I folded 13.5 feet of tapped horn into that cabinet.
Only way I could make it smaller is make it shorter, but then it would not play as low.
Driver is your choice - the Exodus Anarchy is preferred, the TB W6-1139 is a possible substitute.
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When I compared the ED 6 to the Tang Band a while back, it seemed that the ED had more excursion for the same SPL.
.....my only guess is that while the mic is placed in the nearfield, there is so much air movement that it gives false distortion readings....I'll find out tomorrow early AM outdoors...
Ding Ding Ding.......
This would be my guess. I really tried to bottom four of these drivers. I wired them series parallel, and fed them 500 watts at 25 Hz (sine wave). All I did was overheat my amp. No bad noises at all.
Ding Ding Ding.......
This would be my guess. I really tried to bottom four of these drivers. I wired them series parallel, and fed them 500 watts at 25 Hz (sine wave). All I did was overheat my amp. No bad noises at all.
Most low cost mics overload (Clip) in nearfield high SPL measurements. Remember that most SPL ratings are at 1m so in the NF the SPLs are much higher.
Try a program that lets you look at the waveform, a free PC scope program and see if the waveform looks clipped, then pull the mic away and see if the distorted waveform cleans up.
Ken noted this first with the ECM-8000 and I confirmed it while testing a big sub:
http://www.audiokarma.org/forums/showthread.php?t=279240
Try a program that lets you look at the waveform, a free PC scope program and see if the waveform looks clipped, then pull the mic away and see if the distorted waveform cleans up.
Ken noted this first with the ECM-8000 and I confirmed it while testing a big sub:
http://www.audiokarma.org/forums/showthread.php?t=279240
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OK,
I think you guys are right....I hooked Insubnia up to my receiver/plate amp last night....and it did surprisingly well...
Some quick indoor distortion measurements with the Insubnia corner loaded, mic at the listening position, listening position is 13 feet from horn mouth (Bill Fitzmaurice TT-Table Tuba and THT-Tuba Home Theater also measured in same room previously listed below to compare):
NOTE: These are continuous sinewave distortion measurements, a real torture test. You can add ~6dB to these values for program material (unless your program material is high signal strength sinewaves).
Insubnia:
20Hz-86dB @10.1% THD
25Hz-91dB @5.07% THD
30Hz-100dB @5.03% THD
35Hz-104dB @4.4%THD
TT:
12.5Hz-70dB @13% THD
15Hz- 72dB @11% THD
17.5Hz-72dB @11% THD
20Hz- 82.5dB @5% THD
22.5Hz-96dB @5% THD
25Hz- 99dB @5% THD
27.5Hz-105dB @5% THD
30Hz- 106dB @5% THD
THT:
12.5Hz-88dB @5% THD
15Hz- 94dB @ 5% THD
17.5Hz-105dB @5% THD
20Hz- 110dB <2% THD
22.5Hz-110dB <2% THD
25Hz- 110dB <2% THD
27.5Hz-110dB <2% THD
30Hz- 110dB <2% THD
I also figured out partially why the high distortion numbers below 30Hz...the nearfield measurement problem was definitely there, but the Insubnia is also hamstrung by it's response...
Here's a figure showing harmonic distortion % vs dB down from fundamental:
At 20Hz (1st harmonic or fundamental), Insubnia is down by 15dB compared to 40Hz (2nd harmonic), down by 16dB compared to 60Hz (3rd harmonic), and down by 20dB compared to 80Hz (4th harmonic).....
This means that Insubnia is hamstrung by it's own efficiency in it's passband for measuring distortion below 30Hz. Even though it's excursion is controlled, by means of the horn itself, the 1st three harmonics of a 20Hz tone are being 'amplified' by 15, 16, and 20dB respectively. As seen in the graphic, the difference between 10% THD (a harmonic 20dB down from fundamental) and 31% THD (a harmonic 10dB down from fundamental) is huge...and this is what leads to the elevated distortion measurements below 30Hz in the Insubnia, as well as the TT (which also has a falling response below 30Hz). The response curve gives Insubnia no chance for low distortion at 20Hz compared to at 30Hz...
So what does this mean?
Insubnia belts out plenty of bass above 30Hz, and especially above 32Hz, to complement some Indignias. The price paid for such efficiency is that to minimize distortion in the very low freq region below 30Hz, it would be best served by a high-pass which rolls off at around 30Hz, but the highpass is not necessary to prevent over-excursion.....
For it's size, it does VERY well. The TT is a 30"x30"x16" box, the THT a 36"x36"x24" box. Insubnia basically loses 6dB output compared to TT....at a little under 1/3rd the volume of the TT, I think it is a winner....
With a 24dB/oct highpass that just begins to drop at 30Hz (set by my Reckhorn B1), it was keeping up with my mains at 15dB below reference, very clean up to 12dB below reference, where it started showing slight signs of distortion with the THX Amazing Life trailer, which has lots of sub-30Hz info....
To get to 10dB below reference cleanly, you'd need to build a dual-driver double-wide (essentially a 20.75" cube), or have several in the room...highpassed at ~25-30Hz...
Outdoor measurements to come later...
JSS
I think you guys are right....I hooked Insubnia up to my receiver/plate amp last night....and it did surprisingly well...
Some quick indoor distortion measurements with the Insubnia corner loaded, mic at the listening position, listening position is 13 feet from horn mouth (Bill Fitzmaurice TT-Table Tuba and THT-Tuba Home Theater also measured in same room previously listed below to compare):
NOTE: These are continuous sinewave distortion measurements, a real torture test. You can add ~6dB to these values for program material (unless your program material is high signal strength sinewaves).
Insubnia:
20Hz-86dB @10.1% THD
25Hz-91dB @5.07% THD
30Hz-100dB @5.03% THD
35Hz-104dB @4.4%THD
TT:
12.5Hz-70dB @13% THD
15Hz- 72dB @11% THD
17.5Hz-72dB @11% THD
20Hz- 82.5dB @5% THD
22.5Hz-96dB @5% THD
25Hz- 99dB @5% THD
27.5Hz-105dB @5% THD
30Hz- 106dB @5% THD
THT:
12.5Hz-88dB @5% THD
15Hz- 94dB @ 5% THD
17.5Hz-105dB @5% THD
20Hz- 110dB <2% THD
22.5Hz-110dB <2% THD
25Hz- 110dB <2% THD
27.5Hz-110dB <2% THD
30Hz- 110dB <2% THD
I also figured out partially why the high distortion numbers below 30Hz...the nearfield measurement problem was definitely there, but the Insubnia is also hamstrung by it's response...
Here's a figure showing harmonic distortion % vs dB down from fundamental:
At 20Hz (1st harmonic or fundamental), Insubnia is down by 15dB compared to 40Hz (2nd harmonic), down by 16dB compared to 60Hz (3rd harmonic), and down by 20dB compared to 80Hz (4th harmonic).....
This means that Insubnia is hamstrung by it's own efficiency in it's passband for measuring distortion below 30Hz. Even though it's excursion is controlled, by means of the horn itself, the 1st three harmonics of a 20Hz tone are being 'amplified' by 15, 16, and 20dB respectively. As seen in the graphic, the difference between 10% THD (a harmonic 20dB down from fundamental) and 31% THD (a harmonic 10dB down from fundamental) is huge...and this is what leads to the elevated distortion measurements below 30Hz in the Insubnia, as well as the TT (which also has a falling response below 30Hz). The response curve gives Insubnia no chance for low distortion at 20Hz compared to at 30Hz...
So what does this mean?
Insubnia belts out plenty of bass above 30Hz, and especially above 32Hz, to complement some Indignias. The price paid for such efficiency is that to minimize distortion in the very low freq region below 30Hz, it would be best served by a high-pass which rolls off at around 30Hz, but the highpass is not necessary to prevent over-excursion.....
For it's size, it does VERY well. The TT is a 30"x30"x16" box, the THT a 36"x36"x24" box. Insubnia basically loses 6dB output compared to TT....at a little under 1/3rd the volume of the TT, I think it is a winner....
With a 24dB/oct highpass that just begins to drop at 30Hz (set by my Reckhorn B1), it was keeping up with my mains at 15dB below reference, very clean up to 12dB below reference, where it started showing slight signs of distortion with the THX Amazing Life trailer, which has lots of sub-30Hz info....
To get to 10dB below reference cleanly, you'd need to build a dual-driver double-wide (essentially a 20.75" cube), or have several in the room...highpassed at ~25-30Hz...
Outdoor measurements to come later...
JSS
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Got the outdoor measurements done...
RoomEQ Wizard software, Creative USB sound card, Galaxy CM140 spl meter, Behringer A500 amp, el cheapo voltmeter. Reference voltage taken with a 100Hz tone to set up measurement sweep.
2V in, 1m distance, hornresp vs actual, hornresp in pink/magenta, actual in blue:
From 20-60Hz, measurement agrees with hornresp within 1.5dB!!! You can also see that hornresp exaggerates the peaks and dips higher up in freq by a little bit...
Doing these measurements was not easy...it seems birds like to 'call back' to the freq sweeps in force, so I was scaring away birds and waiting for cars to pass by half the time to get a sweep that was 'uncolored'...
The sweep was at 1m, 2V in, nearest boundary 35 feet away.
Distortion testing done at 2m, continuous sine tones, here are the results:
20Hz- Unable to get a good 10% THD reading due to noise, but it would have been in the high 60s, low 70s dB-wise.
25Hz- 79.2dB @ 10.00% THD
30Hz- 93.6dB @ 9.52% THD
35Hz- 97.7dB @ 5.9% THD - my amp's clip led flashed before I could reach 10% THD at 35Hz....which is pretty good news...
I did them at 2m to avoid any mouth air movement issues, you can add 6dB to these meaurements for the equivalent 1m measurements (not too shabby, esp above 30Hz). You can also add another ~6dB for playing program material vs sine tones...sine tones are a torture test...
So, I consider this guy done save for an impedance sweep. Unfortunately, the THD measurements weren't as good as I would have liked below the horn cutoff, but that is kind of a product of the horn design itself...highpass at 30Hz, and you will have a great little horn-loaded sub...
I think this is a good, relatively compact option for an Insubnia...$45 driver, $30 in MDF, $5 in glue, and about 6 hrs total worth of workshop time (before finishing/veneering) not counting waiting for glue to dry...
Oh yeah, wanna see what the response was in room at 2V? Just to reinforce that the room is the most important factor in low frequency response (25Hz highpass filter built into my plate amp):
This is why I made Insubnia as compact as I could. Put 4 of them in room tucked away in the ceiling corners, and you use ZERO floor space, cancel out room modes, and get clean output to 30Hz....
Next is a 20Hz Insubnia using the TB W8-740P, for the people who crave more LF extension...hornresp sim is done, just need to draw it up....
JSS
RoomEQ Wizard software, Creative USB sound card, Galaxy CM140 spl meter, Behringer A500 amp, el cheapo voltmeter. Reference voltage taken with a 100Hz tone to set up measurement sweep.
2V in, 1m distance, hornresp vs actual, hornresp in pink/magenta, actual in blue:
From 20-60Hz, measurement agrees with hornresp within 1.5dB!!! You can also see that hornresp exaggerates the peaks and dips higher up in freq by a little bit...
Doing these measurements was not easy...it seems birds like to 'call back' to the freq sweeps in force, so I was scaring away birds and waiting for cars to pass by half the time to get a sweep that was 'uncolored'...
The sweep was at 1m, 2V in, nearest boundary 35 feet away.
Distortion testing done at 2m, continuous sine tones, here are the results:
20Hz- Unable to get a good 10% THD reading due to noise, but it would have been in the high 60s, low 70s dB-wise.
25Hz- 79.2dB @ 10.00% THD
30Hz- 93.6dB @ 9.52% THD
35Hz- 97.7dB @ 5.9% THD - my amp's clip led flashed before I could reach 10% THD at 35Hz....which is pretty good news...
I did them at 2m to avoid any mouth air movement issues, you can add 6dB to these meaurements for the equivalent 1m measurements (not too shabby, esp above 30Hz). You can also add another ~6dB for playing program material vs sine tones...sine tones are a torture test...
So, I consider this guy done save for an impedance sweep. Unfortunately, the THD measurements weren't as good as I would have liked below the horn cutoff, but that is kind of a product of the horn design itself...highpass at 30Hz, and you will have a great little horn-loaded sub...
I think this is a good, relatively compact option for an Insubnia...$45 driver, $30 in MDF, $5 in glue, and about 6 hrs total worth of workshop time (before finishing/veneering) not counting waiting for glue to dry...
Oh yeah, wanna see what the response was in room at 2V? Just to reinforce that the room is the most important factor in low frequency response (25Hz highpass filter built into my plate amp):
This is why I made Insubnia as compact as I could. Put 4 of them in room tucked away in the ceiling corners, and you use ZERO floor space, cancel out room modes, and get clean output to 30Hz....
Next is a 20Hz Insubnia using the TB W8-740P, for the people who crave more LF extension...hornresp sim is done, just need to draw it up....
JSS
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Thanks Zilch! It was a fun project.
The TH will run roughshod over this one from 25-32Hz, and I am very interested in the TH's distortion profile, to see if sub 25Hz content will be as distorted as in this horn....let's hope it does very well, to give people options...build the slightly bigger TH for more extension, or the smaller FLH for less extension and a smaller cab....
I found a great DIY highpass filter you can build here:
http://www.subwoofer-builder.com/active-filter.htm
Or you can use a Reckhorn B-2....I'd recommend at least 24dB/octave, and set the frequency depending on the max listening level you will use...
JSS
The TH will run roughshod over this one from 25-32Hz, and I am very interested in the TH's distortion profile, to see if sub 25Hz content will be as distorted as in this horn....let's hope it does very well, to give people options...build the slightly bigger TH for more extension, or the smaller FLH for less extension and a smaller cab....
I found a great DIY highpass filter you can build here:
http://www.subwoofer-builder.com/active-filter.htm
Or you can use a Reckhorn B-2....I'd recommend at least 24dB/octave, and set the frequency depending on the max listening level you will use...
JSS
Yay Sawdust! 
So - I actually made some sawdust tonight after dinner. I have all of the parts to the tapped version of the insubnia cut out. I still have the cut-to-fit parts to crosscut, but other than a quick trim with the tablesaw to make sure things are all even, I'm set to go.
I used 1/2" baltic birch, one cabinet did not even take a full 5X5 sheet. I can get good BB here for less than $30 for a 5X5 if I shop around, and I'd much rather work with birch than MDF.
I also got a chance to work with my new saw guide tonight.
Best. Sawguide. Ever.
In addition to the Insubnia, I cut down 3 sheets of 3/4 Arauco ply for another tapped horn sub I am working on. I got all the cutting done in just over two hours.
No, it's not cheap. However, it is pretty much dummy-proof. Since it is zero-clearance, I can split my pencil mark every time, and since it is a clamp-down track-type system, it is basically as accurate as my measuring ability.
Link to guide: http://eurekazone.com/products/detail/sgs.html
I have the 114" package. No affiliation with these guys other than being a very happy customer. I've used other guide systems, panel saws, and I have a very nice table saw. I will cut sheet goods with this system.
Pics or it didn't happen:
I'll get things trimmed to final width and get the baffle machined in the next couple of days, I hope to start the actual assembly on Sunday.
So - I actually made some sawdust tonight after dinner. I have all of the parts to the tapped version of the insubnia cut out. I still have the cut-to-fit parts to crosscut, but other than a quick trim with the tablesaw to make sure things are all even, I'm set to go.
I used 1/2" baltic birch, one cabinet did not even take a full 5X5 sheet. I can get good BB here for less than $30 for a 5X5 if I shop around, and I'd much rather work with birch than MDF.
I also got a chance to work with my new saw guide tonight.
Best. Sawguide. Ever.
In addition to the Insubnia, I cut down 3 sheets of 3/4 Arauco ply for another tapped horn sub I am working on. I got all the cutting done in just over two hours.
No, it's not cheap. However, it is pretty much dummy-proof. Since it is zero-clearance, I can split my pencil mark every time, and since it is a clamp-down track-type system, it is basically as accurate as my measuring ability.
Link to guide: http://eurekazone.com/products/detail/sgs.html
I have the 114" package. No affiliation with these guys other than being a very happy customer. I've used other guide systems, panel saws, and I have a very nice table saw. I will cut sheet goods with this system.
Pics or it didn't happen:
I'll get things trimmed to final width and get the baffle machined in the next couple of days, I hope to start the actual assembly on Sunday.
Another High Pass Filter option
Marchand Electronics offers a 24 dB/octave crossover kit that can be used as a highpass filter.
http://www.marchandelec.com/xm1.html
No experience with it yet, though I intend to try one once I get to use my EP-2500.
Marchand Electronics offers a 24 dB/octave crossover kit that can be used as a highpass filter.
http://www.marchandelec.com/xm1.html
No experience with it yet, though I intend to try one once I get to use my EP-2500.
That's great news about the start of the build!
The X-over/highpass being only $40, it sounds like a cost savings compared to a Reckhorn unit...but what would you use to power it? Do you know of a good + economical 15V power supply?
JSS
Thanks myn,
It actually is an OD FLH, lilmike is the TH guru...next is a 20Hz version with an 8" driver, about 2.5x the size of this one volume-wise, still smaller than TT, and should reach 20Hz with the authority this one reaches 30Hz with...
Can't wait to see what Mike comes up with for the 25Hz version....
JSS
It actually is an OD FLH, lilmike is the TH guru...next is a 20Hz version with an 8" driver, about 2.5x the size of this one volume-wise, still smaller than TT, and should reach 20Hz with the authority this one reaches 30Hz with...
Can't wait to see what Mike comes up with for the 25Hz version....
JSS
Well folks,
After 2 days of 'replacing' my 15" loaded horn subwoofer with Insubnia (it's actually still in the room), I can say that at 15-20dB below reference, the Insubnia doesn't give up much...
I highpassed it so that I hit exactly 10% THD at 20Hz and 5% THD at 25Hz and above at 15dB below reference, and it plays VERY well. Audyssey fixed the rising response to make it a seamless fit with my mains/center/surrounds....
Can you notice that below 30Hz is missing? Of course....but is it a deal-breaker? Absolutely not...most people with HTIBs and 8-10" subs do not have bass this good....
I think this sub will compement Indingias very well, esp. with an EQ package like Audyssey onboard your AVR...
JSS
After 2 days of 'replacing' my 15" loaded horn subwoofer with Insubnia (it's actually still in the room), I can say that at 15-20dB below reference, the Insubnia doesn't give up much...
I highpassed it so that I hit exactly 10% THD at 20Hz and 5% THD at 25Hz and above at 15dB below reference, and it plays VERY well. Audyssey fixed the rising response to make it a seamless fit with my mains/center/surrounds....
Can you notice that below 30Hz is missing? Of course....but is it a deal-breaker? Absolutely not...most people with HTIBs and 8-10" subs do not have bass this good....
I think this sub will compement Indingias very well, esp. with an EQ package like Audyssey onboard your AVR...
JSS
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rvsixer
New Member
maxmercy, any updates on this design? I want a little more than the TT, and a little less than the THT to go with my new mains....
No progress yet.....hard to fold that one on the first few tries, and haven't found the time yet to get it folded properly....it is a long horn...
But, if you can fit a 36"x36"x16" size box, a slim THT with the Dayton DVC 12" is good to 25Hz (and a little below)....and will have more sensitivity than the box I am designing...the penalty is space, of course....
I am designing the 20Hz box so that multiples can be used...as a single it'll still work, but no room-mode cancellation....also, a 'double-wide' option will be there, for more sensitivity and a little more extension...24" cube is the target for the double-wide...we'll see if I can hit it....
As I progress, I'll update....lilmike should have Insubnia Anarchy done before I get to make sawdust on this one....and it should do VERY well....
JSS
But, if you can fit a 36"x36"x16" size box, a slim THT with the Dayton DVC 12" is good to 25Hz (and a little below)....and will have more sensitivity than the box I am designing...the penalty is space, of course....
I am designing the 20Hz box so that multiples can be used...as a single it'll still work, but no room-mode cancellation....also, a 'double-wide' option will be there, for more sensitivity and a little more extension...24" cube is the target for the double-wide...we'll see if I can hit it....
As I progress, I'll update....lilmike should have Insubnia Anarchy done before I get to make sawdust on this one....and it should do VERY well....
JSS
