The Cornu's did very well at the fest. It's the only speaker I've taken there that were put back on so they could be heard again. 
Sounded really nice outdoors placed on pedestals.
http://www.diyaudio.com/forums/club...uver-island-diyfest-2014-a-6.html#post4027983
Cornu's on left
Scott and Cal on the right playing with the big boys after hours. hehe
Sounded really nice outdoors placed on pedestals.http://www.diyaudio.com/forums/club...uver-island-diyfest-2014-a-6.html#post4027983
Cornu's on left
Scott and Cal on the right playing with the big boys after hours. hehe
Hi guys, first time posting (and speaker building for that matter), but I think I'm ready to jump into a 24" Cornu build. I'm really attracted to the low profile wall mount, and they seem like they have a great sound from all the positive comments in this thread. I've read through a fair amount, but there's a lot of information on here and just wanted to ask a few questions:
1) I have access to a CNC router, so I was going to make the channels out of MDF. What's an appropriate thickness for the channel walls? I was thinking 1/8".
2) I'm going to use the Cornu Spiral scalable PDF to make a 24" speaker. Is the line on the PDF the outside edge/centerline/inside edge? Does it particularly matter?
3) As far as drivers go, I was thinking of using one in the Tang Band W4 series, probably the W4-1897. It looks like others have had successful builds with this driver? I guess I'm just looking for some verification that I'm making the right choice as they are a little pricey.
Thanks for any help!
-Pete
1) I have access to a CNC router, so I was going to make the channels out of MDF. What's an appropriate thickness for the channel walls? I was thinking 1/8".
2) I'm going to use the Cornu Spiral scalable PDF to make a 24" speaker. Is the line on the PDF the outside edge/centerline/inside edge? Does it particularly matter?
3) As far as drivers go, I was thinking of using one in the Tang Band W4 series, probably the W4-1897. It looks like others have had successful builds with this driver? I guess I'm just looking for some verification that I'm making the right choice as they are a little pricey.
Thanks for any help!
-Pete
I commend you for wanting to try this out in CNC'd MDF but let me say a few things:
- try the foam core route - it is very easy and fast and is lightweight for easy wall hanging. If it falls off it won't hurt kids or shatter into pieces;
- CNC MDF is very wasteful of material and takes a long time - one slip of the bit and you ruin it;
With that said, you could try to CNC guide channels in the front and rear panels that are 3/16 in wide and use those slots to guide the foam core walls (or bendy plywood or MDF) 1/8in MDF is still thin in my mind, go with at least 3/16 or 1/4in. Those lines should be the middle of the material - not a big deal - maybe scale up by an inch to 25in or 26in. I would suggest that anyway because the 24in will not have enough room for the driver basket and magnet to for in chamber (at least the TB W4-1320SIF had this problem).
The foam core method can be done in 2 to 3 hours ea not including glue drying time for final capping operation.
- try the foam core route - it is very easy and fast and is lightweight for easy wall hanging. If it falls off it won't hurt kids or shatter into pieces;
- CNC MDF is very wasteful of material and takes a long time - one slip of the bit and you ruin it;
With that said, you could try to CNC guide channels in the front and rear panels that are 3/16 in wide and use those slots to guide the foam core walls (or bendy plywood or MDF) 1/8in MDF is still thin in my mind, go with at least 3/16 or 1/4in. Those lines should be the middle of the material - not a big deal - maybe scale up by an inch to 25in or 26in. I would suggest that anyway because the 24in will not have enough room for the driver basket and magnet to for in chamber (at least the TB W4-1320SIF had this problem).
The foam core method can be done in 2 to 3 hours ea not including glue drying time for final capping operation.
Thanks for the quick reply! Milling channels in the front and rear panels definitely sounds like the way to go if I do the foamcore. You covered a lot of the disadvantages of MDF, but does it have any advantages over the foamcore in terms of audio quality?
Scaling up to 26" is totally doable. For channel depth I was thinking 4.5".
Scaling up to 26" is totally doable. For channel depth I was thinking 4.5".
Foamcore can be thin and vibrate and contribute to sound coming from baffle vs horns. Not a totally bad thing though as wooden body music instruments make great sounds this way. It may increase harmonic distortion if you are into hifi aspirations. But if you are after hifi, Cornu is not for you anyway as it imparts its own coloration to the music in a good way.
26 x 4.5 sounds fine. Can make it 4 if you want. The deeper it is the more the bass may overpower the treble.
I see only a small advantage in using bendy ply over foam. If ever there was a speaker that it was made for it, this is it. Now, I very much believe in a wood front and back and I'm not convinced the smaller drivers in the smaller Cornus do the design justice. I have 20", 27" and 36" and there is a marked difference in each. I can't even listen to the two smaller ones anymore. No, that not an exaggeration. I would love to do a larger one but they start getting impractical when it comes to gluing on the second piece. You need two or three people with a glue bottle or it just takes too long.
Drivers recommendations for 20in Cornu
Hi everybody,
First let me say thanks for all the material and help you are bringing to DIY newbies such as me It is definitely inspiring and highly encouraging.
I am quite new to DIY speakers and like many, fell in love with the Cornu design. I already built a micro 14in all-foam version by cannibalizing a pair of cheap logitech z120 multimedia speakers and the results were encouraging enough to make me want to build a more serious (and bigger) version
I am now planning to build a 20in Cornu with MDF front and back panels and foam walls. Tang band and Vifa drivers not being that cheap or easily available in in France, I have had my eyes on Dayton audio RS100-8 or Monacor SP-50X drivers but haven't seen any feedback on this thread on using them. I am a bit uneasy to use smaller 3in drivers (fountek is readily available here) due to higher Fs and lower sensitivity. Has anyone had any success with those Monacor and Dayton in 20in Cornu (with slightly enlarged throat surface)? Or do you have alternative 4in drivers to propose (I would like to keep it under 30/40$ per driver - building cheap is part of the thrill
Can I also suggest that a list of recommended drivers per Cornu size be included in the first post of the thread? There are a lot of information in here but it's getting difficult to retrieve in a 1000+ posts thread!
Thank you for all the help!
Cheers
Hi everybody,
First let me say thanks for all the material and help you are bringing to DIY newbies such as me
It is definitely inspiring and highly encouraging.I am quite new to DIY speakers and like many, fell in love with the Cornu design. I already built a micro 14in all-foam version by cannibalizing a pair of cheap logitech z120 multimedia speakers and the results were encouraging enough to make me want to build a more serious (and bigger) version
I am now planning to build a 20in Cornu with MDF front and back panels and foam walls. Tang band and Vifa drivers not being that cheap or easily available in in France, I have had my eyes on Dayton audio RS100-8 or Monacor SP-50X drivers but haven't seen any feedback on this thread on using them. I am a bit uneasy to use smaller 3in drivers (fountek is readily available here) due to higher Fs and lower sensitivity. Has anyone had any success with those Monacor and Dayton in 20in Cornu (with slightly enlarged throat surface)? Or do you have alternative 4in drivers to propose (I would like to keep it under 30/40$ per driver - building cheap is part of the thrill
Can I also suggest that a list of recommended drivers per Cornu size be included in the first post of the thread? There are a lot of information in here but it's getting difficult to retrieve in a 1000+ posts thread!
Thank you for all the help!
Cheers
Give me a day and I will get sims of these drivers for you in a Cornu. If making out if mdf I would suggest going up to 24in size as Cal suggests. My guess is 24in x 4in should work fine. Welcome on board and please post pics of your Logitech driver 14in Cornu.
If I had time I would give Cal a list of all the drivers I have sim'd but did not keep records of the size of Cornu. In general, 2in drivers are 14in x 2in, 3in drivers are 20 to 24in x 3.5 to 4in. 4in drivers are 24 to 27in x 4in to 4.5in, and 5in drivers are 27in to 36in x 4in to 6in. It is quite a flexible and tolerant design able to accommodate many types of drivers with adjustment of stuffing to balance bass and treble.
If I had time I would give Cal a list of all the drivers I have sim'd but did not keep records of the size of Cornu. In general, 2in drivers are 14in x 2in, 3in drivers are 20 to 24in x 3.5 to 4in. 4in drivers are 24 to 27in x 4in to 4.5in, and 5in drivers are 27in to 36in x 4in to 6in. It is quite a flexible and tolerant design able to accommodate many types of drivers with adjustment of stuffing to balance bass and treble.
Last edited:
Okay, thanks again xrk971
I will wait for your sims before placing my order. 24 inches seems doable.
-----
Some pics and comments about the 14in (actually really 30cm / 12in) Cornu.
I used 5mm foamboard for both front/back panels and channels. Depth is 4cm (1.6in). Throat depth circa 8mm (0.3in).
I didn't have a hot glue gun so used universal glue for the foam (and mastic to fix the drivers to the foam). Holding the 5mm foam channels while glueing was a bit of a pain so I used toothpicks to keep everything in place.
I'm still looking for a way to make them look pretty(sh). Maybe I will cover them with some hand-made crafty paper.
Overall sound is nothing spectacular but definitely much improved from within the original Logitech z120 plastic enclosures. All in all a fun 4 hours project
I will wait for your sims before placing my order. 24 inches seems doable.
-----
Some pics and comments about the 14in (actually really 30cm / 12in) Cornu.
I used 5mm foamboard for both front/back panels and channels. Depth is 4cm (1.6in). Throat depth circa 8mm (0.3in).
I didn't have a hot glue gun so used universal glue for the foam (and mastic to fix the drivers to the foam). Holding the 5mm foam channels while glueing was a bit of a pain so I used toothpicks to keep everything in place.
I'm still looking for a way to make them look pretty(sh). Maybe I will cover them with some hand-made crafty paper.
Overall sound is nothing spectacular but definitely much improved from within the original Logitech z120 plastic enclosures. All in all a fun 4 hours project
Attachments
Hi everybody,
First let me say thanks for all the material and help you are bringing to DIY newbies such as me
I am quite new to DIY speakers and like many, fell in love with the Cornu design. I already built a micro 14in all-foam version by cannibalizing a pair of cheap logitech z120 multimedia speakers and the results were encouraging enough to make me want to build a more serious (and bigger) version
I am now planning to build a 20in Cornu with MDF front and back panels and foam walls. Tang band and Vifa drivers not being that cheap or easily available in in France, I have had my eyes on Dayton audio RS100-8 or Monacor SP-50X drivers but haven't seen any feedback on this thread on using them. I am a bit uneasy to use smaller 3in drivers (fountek is readily available here) due to higher Fs and lower sensitivity. Has anyone had any success with those Monacor and Dayton in 20in Cornu (with slightly enlarged throat surface)? Or do you have alternative 4in drivers to propose (I would like to keep it under 30/40$ per driver - building cheap is part of the thrill
Can I also suggest that a list of recommended drivers per Cornu size be included in the first post of the thread? There are a lot of information in here but it's getting difficult to retrieve in a 1000+ posts thread!
Thank you for all the help!
Cheers
The Monacor SP50-X can work in as small as 30in x 4in but I would go all out and make it 36in x 5in and you will get some real eye-opening bass down to mid 40Hz. You will need to add damping material in channels to tame the bass peak, but that is easy and you will have a quite the conversation piece. As Cal has said, the 36in wins hands down and this is a 5.25 in class driver and deserves a big Cornu.
Here is SP50X Freq Response mounted on wall 1.34cm above floor (don't worry about those peaks - they all smooth out with foam core channel flex and stuffing in channels):
Here is the RS100-8 (really a 3.5in driver) in a 20in x 2.5in Cornu:
Two very different speakers - one is huge and the other is a very moderate size for most types of music with bass down to 85Hz.
If you can get me the T/S params for drivers you want to sim in this format, it will speed things up as I won't have to search for it.
Code:
Def_Driver 'SP50X'
SD=75cm2 |Piston
fs=65.0Hz
Mms=4.5g
Qms=1.95
Qes=0.68
Re=6.8ohm
Le=0.35mH
Bl=4.3Tm
Vas=9L
Def_Driver 'RS100-8' | Dayton 3.5in 0.58 Qts, 3.5mm xmax Sept 18, 2014
SD=35.3cm2 |Piston
fs=90Hz
Mms=3.63g
Qms=2.37
Qes=0.76
Re=6.39ohm
Le=0.49mH
Bl=4.2Tm
Vas=1.415LAttachments
Last edited:
Hey xrk,
My vifa's are still on the way, and I've made it to page 95 of this thread... But I've got an idea I want some thought on.
Forgive my lack of proper terminology and understanding... I'm working on it
I keep thinking about how there are really 2 of the same horns, and if making them different would do anything.
My idea is to make a 2 layer design, similar to the original, but with a twist.
The front layer is the same as always, but block the mouths on 2 sides (ie top and left) and fold those horns back into the back layer of the same depth via a hole in the middle panel. This would lengthen 2 of the 4 horns.
Worth trying?
My vifa's are still on the way, and I've made it to page 95 of this thread... But I've got an idea I want some thought on.
Forgive my lack of proper terminology and understanding... I'm working on it
I keep thinking about how there are really 2 of the same horns, and if making them different would do anything.
My idea is to make a 2 layer design, similar to the original, but with a twist.
The front layer is the same as always, but block the mouths on 2 sides (ie top and left) and fold those horns back into the back layer of the same depth via a hole in the middle panel. This would lengthen 2 of the 4 horns.
Worth trying?
I'm afraid I don't really have the real estate for a 30 or 36in cornu so I will go for the Dayton RS100... many thanks for the sim!
Cheers
Cheers
The Monacor SP50-X can work in as small as 30in x 4in but I would go all out and make it 36in x 5in and you will get some real eye-opening bass down to mid 40Hz. You will need to add damping material in channels to tame the bass peak, but that is easy and you will have a quite the conversation piece. As Cal has said, the 36in wins hands down and this is a 5.25 in class driver and deserves a big Cornu.
Here is SP50X Freq Response mounted on wall 1.34cm above floor (don't worry about those peaks - they all smooth out with foam core channel flex and stuffing in channels):
Here is the RS100-8 (really a 3.5in driver) in a 20in x 2.5in Cornu:
Two very different speakers - one is huge and the other is a very moderate size for most types of music with bass down to 85Hz.
If you can get me the T/S params for drivers you want to sim in this format, it will speed things up as I won't have to search for it.
Code:Def_Driver 'SP50X' SD=75cm2 |Piston fs=65.0Hz Mms=4.5g Qms=1.95 Qes=0.68 Re=6.8ohm Le=0.35mH Bl=4.3Tm Vas=9L Def_Driver 'RS100-8' | Dayton 3.5in 0.58 Qts, 3.5mm xmax Sept 18, 2014 SD=35.3cm2 |Piston fs=90Hz Mms=3.63g Qms=2.37 Qes=0.76 Re=6.39ohm Le=0.49mH Bl=4.2Tm Vas=1.415L
Hey xrk,
My vifa's are still on the way, and I've made it to page 95 of this thread... But I've got an idea I want some thought on.
Forgive my lack of proper terminology and understanding... I'm working on it
I keep thinking about how there are really 2 of the same horns, and if making them different would do anything.
My idea is to make a 2 layer design, similar to the original, but with a twist.
The front layer is the same as always, but block the mouths on 2 sides (ie top and left) and fold those horns back into the back layer of the same depth via a hole in the middle panel. This would lengthen 2 of the 4 horns.
Worth trying?
That's an interesting idea, draw a sketch of where your channel switches fron front side to backside, as I don't quite understand the expansion profile. Is it then contracting after it flips sides? Not a bad idea as that can be a tapered mass loaded TL which may give some deeper bass. In fact, on the Cornu website, one of their ideas was a spiral tapered TL - rather than expanding horns. Doing this without a simulation first may not get you very good results as I know from my many experiments prior to being able to model something. It is fun and can be a good learning experience though, but don't expect it to work the first time by trial and error.
That's the nice thing with FC, easy to try crazy ideas...
I was about to place my order and found another European supplier with a big choice of Tang band drivers... can I pester you for a sim on the Tang Band W4-1052SDF? On paper, the lower fs and higher sensitivity are appealing but would that work with say a 24in Cornu?
SD=57cm2
fs=70.0Hz
Mms=4.61g
Qms=4.8
Qes=0.48
Re=4ohm
Le=0.08mH
Bl=4.1Tm
Vas=0.18 ft.³
Thanks again!
SD=57cm2
fs=70.0Hz
Mms=4.61g
Qms=4.8
Qes=0.48
Re=4ohm
Le=0.08mH
Bl=4.1Tm
Vas=0.18 ft.³
Thanks again!