You aren't factoring the speed of sound into the equation. Where is the SPL the highest? At the throat or at the mouth? The throat, right? What is SPL? Sound Pressure Level. Pressure on the horn walls.
Cal - thanks for the heads up - I'm not back in town until Tuesday - so I'll pray that the rest of the full-range-foam-core-speaker-freaks in North Van don't scoop me on it!
Thanks so much for checking - I guess Michael's off Main is best place for glue sticks, x-acto knives and along with gold stars and glitter to decorate with ?
I liked the look of those rolling knives for scoring - any sources for those?
thanks again Cal.
Thanks so much for checking - I guess Michael's off Main is best place for glue sticks, x-acto knives and along with gold stars and glitter to decorate with ?
I liked the look of those rolling knives for scoring - any sources for those?
thanks again Cal.
When I said "speed of sound", I was referring only to its role in generating pressure differentials. It's the pressure differential between the two sides of a wall that make it flex. In a Cornu, the pressure differential between two sides of each curved wall is low at bass frequencies and increases at higher frequencies. Conversely, the front/rear panel flex is highest at low frequencies.
I'm not familiar with them. The box cutter with just the nib sticking out was perfect for scoring. Built in depth guage that way.
So we have no worries about using the foam core for the spirals and should use wood or something stiff for the baffles. I knew this would work out.
Hello All
Here are my newest cornu's ready to hang on the wall.
The box is 15" x 2.5" and the front panel is 16". I like the front a bit bigger so you don't see the sides as much. They look like they are floating off the wall. The drivers are a pair of 2.5" that I pulled out of a Bose sound system found at a thrift store. The art work is one of my leaf ring series printed on canvas and mounted on the front foam board. I stuffed the speaker chamber but nothing in the horns. That worked well with other ones I have made and seems good for these well. They sound fantastic. Much better than the should. Great bass and very nice mid and highs
I really don't understand how these things can sound so good
hope you like them
Here are my newest cornu's ready to hang on the wall.
The box is 15" x 2.5" and the front panel is 16". I like the front a bit bigger so you don't see the sides as much. They look like they are floating off the wall. The drivers are a pair of 2.5" that I pulled out of a Bose sound system found at a thrift store. The art work is one of my leaf ring series printed on canvas and mounted on the front foam board. I stuffed the speaker chamber but nothing in the horns. That worked well with other ones I have made and seems good for these well. They sound fantastic. Much better than the should.
Great bass and very nice mid and highs I really don't understand how these things can sound so good
hope you like them
Attachments
In case you guys may have missed seeing this driver, I think it will sound real good in a 32 in x 5 in deep cornu. Don't let the low price fool you, we are planning to use this in the Decware DNA homage foam horn. It can reach 30 Hz in the right cabinet. $3.60 ea at Madisound. 89 dB Qts of 0.53 and 5.25 in class Nd driver.
The Madisound Speaker Store
The Madisound Speaker Store
Benedetto,
The simple version will not have a middle plate, just front and back with channels. The FE103S will be suited for a Cornu from 61 cm x 61 cm all the way to the usual full size of 75 cm x 75 cm. The depth of the channels can range from 9 to 10 cm. The plans are posted as a pdf by Planet10 somewhere in this thread. Scale it to the size you want. When you say you will build it in situ, you mean do it live at an event?You may want to practice scoring and bending and hot melt gluing curved channels before doing it at a festival. There is a learning curve and you will be much faster and neater once you have figured out the tricks by playing around with it first.
Good luck.
X
The simple version will not have a middle plate, just front and back with channels. The FE103S will be suited for a Cornu from 61 cm x 61 cm all the way to the usual full size of 75 cm x 75 cm. The depth of the channels can range from 9 to 10 cm. The plans are posted as a pdf by Planet10 somewhere in this thread. Scale it to the size you want. When you say you will build it in situ, you mean do it live at an event?You may want to practice scoring and bending and hot melt gluing curved channels before doing it at a festival. There is a learning curve and you will be much faster and neater once you have figured out the tricks by playing around with it first.
Good luck.
X
I want to cut out the curves in advance and use it as a "curve guide".
Exact, on the 6th Frickelfest
This doesn't bother me. Old man got some skills...
One point why i want to do it over there is,
i don't want to transport so much air over 300km in a small hybrid car.
Using a curve guide is a completely different construction technique than what is described and has been used in this thread: the curves are made by hot melt gluing small curved sections at a time by bending the channels by hand and holding in place while the hot melt glue sets (20 seconds). In this way, if you can trace the curve on the flat back panel, laying down a channel to follow any arbitrarily drawn curve is possible (within the bend radius limit of the scored foam core). If you have a curve guide with a slot for the channels already, the construction method is to cut the middle panel slot (very time consuming) and then all that remains is to glue the channels to the middle slot. If you are doing hot melt this will go fast. The final glue to the front and back panels can be done simultaneously and if done with PVA glue (recommended) will take 4 to 6 hours, or with Gorilla glue (messy and takes 30 minutes to cure), or 5 minute epoxy (a potential sticky mess and you have to work fast). Then set clamp weights like books on top to ensure a flat and tight seal on the panels.
The method that we all used, which is to glue sections at a time and hand bending is nice because it shows that anyone can do it if you can handle a hot melt glue gun. Really takes no more than 30 to 45 minutes to do all the channels.
Frickelfest sounds like fun.
Let us know how it goes.
The method that we all used, which is to glue sections at a time and hand bending is nice because it shows that anyone can do it if you can handle a hot melt glue gun. Really takes no more than 30 to 45 minutes to do all the channels.
Frickelfest sounds like fun.
Let us know how it goes.