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I haven't tried either of those Fostex drivers, but I do know that the TC9FD sounds good in a Cornu. The Fostex may work very well - the sims certainly support it. There is less xmax on the Fostex so it really needs an optimized BLH to squeeze the bass out. The Vifa with its higher Qts gets lower bass. Between these, I would pick the Vifa. No one has tried the FF85WK so it would be great to get another data point. It won't sound bad - I just can't be sure it will sound great.
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The whole idea behind a Cornu is zero footprint, high WAF and to see the expression on your friends' faces. If you start redesigning it as a single horn that's fine but it's not a new or particularly exciting idea and it's not a Cornu. If you corner mount it, you have wasted the space behind it and besides, high quality corner horns have been around for a long time.
Methinks you guys are thinking either too much or too little. Time to go build a 48"er.
Methinks you guys are thinking either too much or too little. Time to go build a 48"er.
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Here is a foam core and hot melt glue corner BLH. It is a floorsstander though.
http://www.diyaudio.com/forums/full-range/227460-fh3-inspired-foam-core-mini-build.html
Plan:
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Yes, TC9FD is a great driver. Perhaps the best 3.5in to 4in driver at any price below $60. More info on how good that driver sounds here:
http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-5in-full-range-drivers.html
http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-5in-full-range-drivers.html
Finally......done
Finally I've achieved this long term objective : to build a pair of Cornu.
As you will see from photos I've been applying a kind of solution to make the front solid to the spirals and rear, with this method I’m sure that the wood won’t move and there will be no vibrations.
For the moment I’ve not sealed the spiral to the front so may be some “loss”, this is because I’d like to try different stuffing configurations.
I’m using a pair of Jordan’s Eikona and applying suggestions by XRK971 (thanks) : 75x75 cm , 10 cm thickness.
Wood is 1cm thick.
The preamp is a Pete Millett’s low mu preamp (Low-mu preamp)
The amp is a class-D amplifier (up to 100W)
Source : I use a Squeezebox classic from which can access to all my music collection.
Sound : For the moment the sound is good but not fantastic, I seem to have high missing and low are not that present, comparing with previous speakers.
I don’t know if :
- maybe Eikonas need some rollup (ie make them sound a good quantity of time) or
- maybe there’s too much stuff in the channels (please see the photos) or
- maybe I should seal the front with the spirals
I’m going to try to quit some stuff and check how the sound changes, after that will seal with silicone and make the speakers sound.
If you have any suggestions based on your experience they will be really welcome, as for some test music to check sound quality.
Thanks again for all the help and the presence of this space, best regards.
gmonno (madrid)
Finally I've achieved this long term objective : to build a pair of Cornu.
As you will see from photos I've been applying a kind of solution to make the front solid to the spirals and rear, with this method I’m sure that the wood won’t move and there will be no vibrations.
For the moment I’ve not sealed the spiral to the front so may be some “loss”, this is because I’d like to try different stuffing configurations.
I’m using a pair of Jordan’s Eikona and applying suggestions by XRK971 (thanks) : 75x75 cm , 10 cm thickness.
Wood is 1cm thick.
The preamp is a Pete Millett’s low mu preamp (Low-mu preamp)
The amp is a class-D amplifier (up to 100W)
Source : I use a Squeezebox classic from which can access to all my music collection.
Sound : For the moment the sound is good but not fantastic, I seem to have high missing and low are not that present, comparing with previous speakers.
I don’t know if :
- maybe Eikonas need some rollup (ie make them sound a good quantity of time) or
- maybe there’s too much stuff in the channels (please see the photos) or
- maybe I should seal the front with the spirals
I’m going to try to quit some stuff and check how the sound changes, after that will seal with silicone and make the speakers sound.
If you have any suggestions based on your experience they will be really welcome, as for some test music to check sound quality.
Thanks again for all the help and the presence of this space, best regards.
gmonno (madrid)
Attachments
Gmonno,
Wow, beautiful work! And what a driver to use on it. How is it held together presently is not glued in the front? If not glued and sealed - you won't get much bass as little pinhole leaks can collapse the quarter wave air column. If you ever play a flute you know that a finger seal that is barely leaking will not achieve the low C note. Same thing here. So if you have not glued it yet don't worry about not any bass.
A few observations:
1. The open cell foam in the channels may be constricting the flow too much. Inwould remove the foam at the pinch point, leave the other foam in larger section and in chamber.
2. Add polyfill in the chamber and that lets you adjust after glueing.
3. Glue the front panel on and make sure you have a good mechanical fit to ensure the seal has no leaks.
Good luck!
Wow, beautiful work! And what a driver to use on it. How is it held together presently is not glued in the front? If not glued and sealed - you won't get much bass as little pinhole leaks can collapse the quarter wave air column. If you ever play a flute you know that a finger seal that is barely leaking will not achieve the low C note. Same thing here. So if you have not glued it yet don't worry about not any bass.
A few observations:
1. The open cell foam in the channels may be constricting the flow too much. Inwould remove the foam at the pinch point, leave the other foam in larger section and in chamber.
2. Add polyfill in the chamber and that lets you adjust after glueing.
3. Glue the front panel on and make sure you have a good mechanical fit to ensure the seal has no leaks.
Good luck!
Many thanks XRK971.
The front is mantained in this way : if you look at the detail photo, I used a strong clue to link the rear and a "L" like aluminium shape, and used another "L" glued with front (not visible in this photo).
So I can join togheter the two "L"s --> now forming a "C" and screw them.
Will follow your auggestion about open cell foam and glueing rear and front.
Last question, do you have some "reference sound" CD to test your speakers or were may ask for suggestions?
Thanks, as usual
gmonno
The front is mantained in this way : if you look at the detail photo, I used a strong clue to link the rear and a "L" like aluminium shape, and used another "L" glued with front (not visible in this photo).
So I can join togheter the two "L"s --> now forming a "C" and screw them.
Will follow your auggestion about open cell foam and glueing rear and front.
Last question, do you have some "reference sound" CD to test your speakers or were may ask for suggestions?
Thanks, as usual
gmonno
Attachments
Last edited:
You can use the high quality reference sound clips from this thread:
http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-5in-full-range-drivers-25.html#post4249660
http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-5in-full-range-drivers-52.html#post4266322
The CD by Anne Bisson "Blue Mind" is expertly mastered and the quality is very good, I like "September in Montreal" and "Soothing Your Soul". It has a lot of dynamic range. As well as Dave Brubeck's "In Their Own Sweet Time". Stevie Ray Vaughn's "Tin Pan Alley" is also good. Rebecca Pidgeon's "Spanish Harlem". Dire Straits' "Private Investigations" is also very good. Hope this helps.
http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-5in-full-range-drivers-25.html#post4249660
http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-5in-full-range-drivers-52.html#post4266322
The CD by Anne Bisson "Blue Mind" is expertly mastered and the quality is very good, I like "September in Montreal" and "Soothing Your Soul". It has a lot of dynamic range. As well as Dave Brubeck's "In Their Own Sweet Time". Stevie Ray Vaughn's "Tin Pan Alley" is also good. Rebecca Pidgeon's "Spanish Harlem". Dire Straits' "Private Investigations" is also very good. Hope this helps.
Last edited:
8 inch full range driver
Hi All I plan to build the cornu spiral using a Seas prestige 8 inch full range driver.
H1597-08 FA22RCZ
Need your advise how I should increase the size of the spiral enclosures, is there a specific calculation involved to match the larger driver size?
Thanks
Sazali
Hi All I plan to build the cornu spiral using a Seas prestige 8 inch full range driver.
H1597-08 FA22RCZ
Need your advise how I should increase the size of the spiral enclosures, is there a specific calculation involved to match the larger driver size?
Thanks
Sazali
An 8inch driver will result in a very large Cornu if you simply scaled the plans with driver size in order to make a central chamber large enough to hold the driver. The Cornu is designed for a nominal 4in driver. So 8in class is twice the width or 1.5m x 1.5m (25 square foot baffle). The depth will be circa 6in to 8in. That is very large. I suggest you do a quick and easy build with a small 3 in driver first to learn and practice the construction technique prior to embarking on such an ambitious project. I could simulate this for you as a 2x scale Cornu if you are still interested in pursuing it. It will dig deep - probably 30Hz and have a lot of bass gain.