Adason,
Yes, there can be intermodulation. How big of an effect we will have to see. Danley actually puts a coil across the compression driver to short out stiffen the diaphragm from the modulation. The bass ports are relatively close to the mouth I wonder how much pressure goes back. The impedance and damping factor of the amp is a key parameter here as an open circuit SB65 will probably flap around whereas one connected to amp is relatively stiff and resistant to force.
Yes, there can be intermodulation. How big of an effect we will have to see. Danley actually puts a coil across the compression driver to short out stiffen the diaphragm from the modulation. The bass ports are relatively close to the mouth I wonder how much pressure goes back. The impedance and damping factor of the amp is a key parameter here as an open circuit SB65 will probably flap around whereas one connected to amp is relatively stiff and resistant to force.
X,
The coil is simply part of DSL's crossover (any "second order" passive crossover uses a coil in parallel with the HF driver, and at minimum a capacitor in series), it is not used to "stiffen the diaphragm". Even with no passive components, there are no measurable modulation effects from the dual 10" on the HF driver output in my SynTripP, and they are a lot closer to the throat than yours.
I would be surprised if there were measurable modulation effects on the HF driver from the SPL produced from the woofers in your project, or others that place the woofer ports near the throat.
On another note, just found that 1/8" felt lining portions of the interior walls on the TC9/Maltese horn made a very large reduction in HF ripple- from +/-4 dB, to near that of a compression driver, around +/- 1dB, with only about one dB loss of sensitivity. Also made polar response more uniform.
You might give it a try, might tame the HF roughness on your tractrix as well.
Art
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the most damping of the internal walls the better for linearity in the mid-highs (in axis)?
I saw there is very thin foam as well : 3 mm = 1/8" ! if open cells, could be good and cleaner looking than felt...
I saw there is very thin foam as well : 3 mm = 1/8" ! if open cells, could be good and cleaner looking than felt...
Nice find there - do you have data to show?
Regarding the coil across the CD - I know it would just be part of the XO - but I specifically saw a post where I think Danley or someone claimed that he did it for that reason, even in the case of an active all DSP synergy.
While waiting for the volume filler for the second woofer to be printed, I have been just listening to the horn with dual woofers. The bass of course is about now +6dB with dual 8ohm woofers wired in parallel. I will need to re-EQ once the volume filler is done. However, it sounds quite nice - with or without the blankets on the back, the bass is quite substantial and deep as a dipole/cardiod.
There might be something to the simplicity of a dipole horn? Sure keeps the enclosure simple 🙂
There might be something to the simplicity of a dipole horn? Sure keeps the enclosure simple 🙂
Attachments
When I started this project, I had an idea inspired by Xrk's foam core home made horn loaded full range driver projects.
The idea was to take his experiments and translate it onto a modern high tech CD horn, thereby getting the best of horn technology, horn loaded full range drivers, and the synergy horn layout for point source behaviour.
I felt this could provide low HD, controlled directivity, flat phase response, and high sensitivity combined in a smaller form factor.
I was going to go it alone, had bought the horn and full range driver and was trying to get to grips with the modelling software.
Then, Xrk took me under his wing and offered to help out with all the modelling.
That was just over three weeks ago. And now thanks to the help and encouragement on this forum I have just finished the first one. Thanks guys!
There are also about 6 others builds in progress I believe inspired by the potential before we have even finished a full prototype! So hopefully soon, others will finish too - I think X is closest behind after me - he was going to sit this one out, but after my initial measurements he bought into it too!
Measurements to follow....fingers crossed!
The idea was to take his experiments and translate it onto a modern high tech CD horn, thereby getting the best of horn technology, horn loaded full range drivers, and the synergy horn layout for point source behaviour.
I felt this could provide low HD, controlled directivity, flat phase response, and high sensitivity combined in a smaller form factor.
I was going to go it alone, had bought the horn and full range driver and was trying to get to grips with the modelling software.
Then, Xrk took me under his wing and offered to help out with all the modelling.
That was just over three weeks ago. And now thanks to the help and encouragement on this forum I have just finished the first one. Thanks guys!
There are also about 6 others builds in progress I believe inspired by the potential before we have even finished a full prototype! So hopefully soon, others will finish too - I think X is closest behind after me - he was going to sit this one out, but after my initial measurements he bought into it too!
Measurements to follow....fingers crossed!
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Bushmeister,
Very nice!!! Thanks for being so motivated and so quick! It has been a real pleasure working on this with you and getting to see your progress and the great results you were getting. You were right - at first it was a vicarious enjoyment. But I just could resist once I saw the initial results which looked so darned good. Thanks for your encouragement and all the encouragement and tips and help from others in this thread. A big thanks to Byrtt and Weltersys.
Well done man.
🙂
Very nice!!! Thanks for being so motivated and so quick! It has been a real pleasure working on this with you and getting to see your progress and the great results you were getting. You were right - at first it was a vicarious enjoyment. But I just could resist once I saw the initial results which looked so darned good. Thanks for your encouragement and all the encouragement and tips and help from others in this thread. A big thanks to Byrtt and Weltersys.
Well done man.
🙂
Excellent Bushmeister!
Please make a summary of components used, drivers, horn model, woofer, entry point distance and area, closed box volume.
Please make a summary of components used, drivers, horn model, woofer, entry point distance and area, closed box volume.
Those look pretty good! To clarify, you have not touched the EQ you developed with bare horn and drivers sans baffle and box? The variations are small and consistent over angular variation so re-EQ'ing with box should result in superb results.
You will get there but wondering how sealed box affects bass extension. Looks like you still are getting down to 40Hz easily???!
And.... Can't wait to see how all that first class dampening treatment inside and Sorbothane have worked with regards to HD. 😀
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Arcgotic - nearly everything you need is on this thread - but I will summarize when happy with design. There are many other designs using the same ethos currently underway - I think mine is the only one with the SB65 fullrange, SB23 8 -nchers and the 18sound XT1464 horn horn though.
Other designs may be better than my setup - so might be best to await the intellect and skills of Xrk - who is doing amazing stuff with his 3D printer.
Regarding EQ and crossover slopes - I use minidsp - so EQ is entirely indiviual driver specific in finished cabinet - i.e. of no help to you. Slopes are a Harsch XO at 500 hz - as discussed at length here and in it's own thread.
Other designs may be better than my setup - so might be best to await the intellect and skills of Xrk - who is doing amazing stuff with his 3D printer.
Regarding EQ and crossover slopes - I use minidsp - so EQ is entirely indiviual driver specific in finished cabinet - i.e. of no help to you. Slopes are a Harsch XO at 500 hz - as discussed at length here and in it's own thread.
Those look pretty good! To clarify, you have not touched the EQ you developed with bare horn and drivers sans baffle and box? The variations are small and consistent over angular variation so re-EQ'ing with box should result in superb results.
You will get there but wondering how sealed box affects bass extension. Looks like you still are getting down to 40Hz easily???!
Xrk - you are right - plenty of room to improve the responses!
Re: bass - Once the box was built, heavily braced and lined, I reckon the actual volume is closer to 40 litres - so a little over-sized. The bass is extraordinary and there will be no need for a sub-woofer. I will run a high level sweep now to check distortion.
Cheers X! you are right without you, Brytt, wesayso and Weltersys this project would probably not have got finished in 2016!
You have been a constant help and have pushed me to get his done in record time.
So some initial results...
I missed this post on previous page!!! Very nice.
Yes, I forgot to mention thanks to Wesayso for the great tip on how to EQ with gated measurements. My bad.
This frequency response and measured phase are excellent. The Harsch XO is probably working perfectly in this setup with a textbook 55deg bump from nominal, otherwise flat over bandwidth of interest. Amazing result.
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Congratulations Bush.
Really you've done an excellent job. Obviously you're a really skilled and meticulous construcctor.
I have the absolutely certain that all measures from your box would support the high quality of this design and the nice construction that you has made.
My most sincere thanks for sharing with us all their evolution.
Regards.
Bushmeister,
Those HD figures in the bass are very impressive for a small dual 8in woofer in a sealed box. -43dB at 80Hz and 100dB is awesome. -33dB at 30Hz is still awesome and up there with the best in this driver class range from what I have seen.
For the HF, you may be getting some HD from surround rubbing on the dampening foam in the driver mount. That rise from 2k looks suspicious.
Those HD figures in the bass are very impressive for a small dual 8in woofer in a sealed box. -43dB at 80Hz and 100dB is awesome. -33dB at 30Hz is still awesome and up there with the best in this driver class range from what I have seen.
For the HF, you may be getting some HD from surround rubbing on the dampening foam in the driver mount. That rise from 2k looks suspicious.