Hi all!
I have been trying to figure out the Danley BC line of subbs.
This is what i think is going on:
If you try to get a high power density from powerful (low Qes, High Bl, high mms) drivers like B&C 12NW100 in a tapped horn you get a very high compression or a very deep depression in the middle of the passband, like i show below:
http://oi59.tinypic.com/14mzaxv.jpg
I have two more posts to make, please wait until i have posted them before you reply.
Cheers,
Johannes
I have been trying to figure out the Danley BC line of subbs.
This is what i think is going on:
If you try to get a high power density from powerful (low Qes, High Bl, high mms) drivers like B&C 12NW100 in a tapped horn you get a very high compression or a very deep depression in the middle of the passband, like i show below:
http://oi59.tinypic.com/14mzaxv.jpg
I have two more posts to make, please wait until i have posted them before you reply.
Cheers,
Johannes
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To fill that depression and get a much higher efficiency you can add a front resonator like a quarterwave bandpass design:
[image]http://oi58.tinypic.com/2eewo6e.jpg[/image]
[image]http://oi58.tinypic.com/2eewo6e.jpg[/image]
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And you get a combined output like this:
[image]http://oi61.tinypic.com/15wkvfq.jpg[/image]
The quarterwave based front resonator will increse the efficiency very dramatic, and will act like a filter, lowering distortion.
The phaserespons of this modified tapped pipe/tapped horn is very similar to the phaserespons from the BC412 and BC415.
This is not optimized and there are several more aspects of it that is not shown in the very simplified Hornresp-simms.
Cheers,
Johannes
[image]http://oi61.tinypic.com/15wkvfq.jpg[/image]
The quarterwave based front resonator will increse the efficiency very dramatic, and will act like a filter, lowering distortion.
The phaserespons of this modified tapped pipe/tapped horn is very similar to the phaserespons from the BC412 and BC415.
This is not optimized and there are several more aspects of it that is not shown in the very simplified Hornresp-simms.
Cheers,
Johannes
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Please upload the screenies Directly in here, as i can't view them from there, due to LOTS of JavaScripting/Tracking etc blocking i have in place on my comp.
How do i do that?
I thought i had to use something like Tinypic for uploading pictures.
Cheers,
Johannes
I thought i had to use something like Tinypic for uploading pictures.
Cheers,
Johannes
No you don't need to upload offsite, & it's better for Everyone if people don't !
How do I attach files or post pictures in the forum? diyAudio - FAQ
Looking forward to viewing them in here.
How do I attach files or post pictures in the forum? diyAudio - FAQ
Looking forward to viewing them in here.
Hi Circlomanen,
I thought BC stands for boundary coherent, and the models are BC415, BC412 and BC218? They all seem to be FLH not TH?
Regards,
I thought BC stands for boundary coherent, and the models are BC415, BC412 and BC218? They all seem to be FLH not TH?
Regards,
Yes. They might be FLH. I don't know if my idea is right. I think so, based on the phase and spl respons, respons curve and the outside look of the boxes.
I might be totally wrong. This is why i want to discuss this idea here.
Cheers,
Johannes
Hi Circlomanen,
Here is another thread on that subject:
http://www.diyaudio.com/forums/subw...ttempt-reverse-engineering-danley-design.html
See, Post #23 for a quick trial sketch of the internals.
Regards,
Here is another thread on that subject:
http://www.diyaudio.com/forums/subw...ttempt-reverse-engineering-danley-design.html
See, Post #23 for a quick trial sketch of the internals.
Regards,
It does not look like a FLH. There is no visable expansion in the "chamber" inside the mouth. I can not see any reason to have souch a small mouth on an FLH if one wants efficiency and high spl.
Regardless of this idea being simiular to the BC412 or not, i believe it is a novel idea to get 4 - 6 dB more spl from any given driver compared to tapped horns like the THAM series.. Plywood is cheaper then extra drivers, and i have never simmed another kind of box with this kind of max spl and efficiency, except full size huge hyperbolic horns.
cheers,
Johannes
I had not seen the BC-218 before. That sure looks like a horn.
The BC412 nd 415 does not look like a regular front loaded horn.
Tom Danley says "The BC415 is another unique subwoofer alignment from Danley Sound Labs" and it does not sound like he means a normal FLH or Tapped Horn.
This is why i started another thread, since i believe there is something else going on here.
Cheers,
Johannes
Thanks for the info about the BDEAP patent. I am familiar with the BDEAP. I don't understand why Danley should say that it is a "unique subwoofer alignment " since BDEAP can no longer be considered "unique". It is a 10 year old patent.
I built my first Tapped Horn in 2003 or 2004. I saw Tom Danley post something about it on a forum (this?) and i built it with a small 5 inch driver. I did not simulate anything. It was way before Hornresp could sim tapped horns. I have been following his designs since then, and i believe this is something new.
I can not see why he would not say something about tapped horns, front loaded horns or BDEAP if that was all it was?
Cheers,
Johannes
I built my first Tapped Horn in 2003 or 2004. I saw Tom Danley post something about it on a forum (this?) and i built it with a small 5 inch driver. I did not simulate anything. It was way before Hornresp could sim tapped horns. I have been following his designs since then, and i believe this is something new.
I can not see why he would not say something about tapped horns, front loaded horns or BDEAP if that was all it was?
Cheers,
Johannes
My memory is real dim now, but doesn't Brad ? Servo-Drive own the rights to all he did there, so had to come up with new patent variations for all his prior designs, making them 'unique', so to speak?
GM
GM
Here is three Hornresp pictures.
Please compare both phase and spl with his BC-415. Very similar.
The max spl is pretty impressive for two 10 inch Faital Pro 10HP1020 in an single enclosure, 2 pi. No tapped horn with a single 12 or two 10 inch drivers i have ever simmed or built can deliver this kind of spl with the pronounced peak around 90 Hz and this extreme efficiency.
Cheers,
Johannes
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The Hornresp spl respons is a little to hot around 100 Hz.
In later iterations i have tamed this peak about two dB. Otherwise it would be a very pronounced kick-bin.
Fun, but not very accurate.
In later iterations i have tamed this peak about two dB. Otherwise it would be a very pronounced kick-bin.
Fun, but not very accurate.
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Just to push the limits a bit, i wanted to test a really small and weak driver.
This is simmed with a 4 inch, 40 watt, +- 3 mm xmax, cheap driver.
Scan-SpeakDiscovery 12W/8524G00
I think it is a pretty impressive respons and max spl for such a small enclosure and driver.
This is simmed with a 4 inch, 40 watt, +- 3 mm xmax, cheap driver.
Scan-SpeakDiscovery 12W/8524G00
I think it is a pretty impressive respons and max spl for such a small enclosure and driver.
A quick estimate of the path length using this fold scheme yields a 2.08m distance which is only good for 80Hz. I think there needs to be more folds to it because the response curve has a knee at 36Hz.