297mm x 210mm sheet of paper = A4.......... come get me Euro cops.
Why would they?
It's A4 all over Europe.
It is based on a 1:√2 ratio first suggested by the german scientist Georg Christoph Lichtenberg in 1786, temporarily introduced in France shortly after but soon forgotten.
Hell knows what the british used before it was re-introduced as DIN A4 in 1922.
(DIN = Deutsche Industrie Norm = German Industrial Norm)
The odd size in mm comes about because A0 is 1m^2 in said ratio, A1 half the area, A2 half of that again and so on.
That was a joke - or more like out and out blatant sarcasm.
The answer to what we English used is Fullscrap/Fullscrape/Fools scrap / scrape, which is about 1/2inch / 12.5mm overall larger - used for typing, not for printing as common Press Plate/Blanket Cylinders and Plates are too narrow/short leading to edge and tail bleeding on the rear of the substrate...... this is if my memory serves me correctly, It's been a while since I swatted up on this info while studying for my RSA Degree in the Fine Arts Of Printing.
??? HR starts with a default design or you can use an existing one to add a new one. If starting with one that's already a horn, then clear the S1, etc. fields to begin anew.
You're welcome! Well, it's much more detailed, dimension wise. If you just want the numbers, any Windoze text reader should suffice, such as Notepad. For plotting it out you'll need Excel or similar, which will probably require a 'dummies' book if you don't know how to plot designs with them.
GM
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![1005 horn cell design [csv file in Excel].gif](/community/data/attachments/292/292188-ea819c2a5f7b0357a33d4cf1ffa3f59c.jpg)
Pano,
It just seems silly to have to try and measure down into the throat of one of these multicells and measure accurately in the narrow sections. Also if you are a bit off in one cell you have to multiply the error by the number of cells you are going to create. The math is simple enough that you should only need the initial opening which here I think you are talking about 1.4" and the final mouth size. The length would be easy as the center cell straight down the axis will give you the length of the horn. Plug those numbers into whatever software you are using and it should give the proper results. I am not familiar with the hornresp software and haven't looked it up. Is that freeware or is this a purchased software program? I have never needed much more than a calculator and a piece of paper and a good understanding of what you are trying to achieve. Until you get into the other aspects such as dispersion angles and how you are going to create a specific dispersion angle in something like a radial horn then things do stay rather simple. It has been years since I have seen anyone use a multicell in anything that I have been around, I did move these horns many times in the olden days doing concert sound but that was long ago. I think that I know someone here in California who probably still has some of these in storage if he hasn't sold them all off. I'm still not sure why this is the direction you are following for a hifi system in a small room but you must all have some sonic quality that you like here. I still have old 511 horns in the living room in some old Barcelona enclosures with surprise to me at the time they came with air suspension 15" drivers. I thought that they would have the A7 drivers in them and was very surprised how good they actually sounded at the time.
It just seems silly to have to try and measure down into the throat of one of these multicells and measure accurately in the narrow sections. Also if you are a bit off in one cell you have to multiply the error by the number of cells you are going to create. The math is simple enough that you should only need the initial opening which here I think you are talking about 1.4" and the final mouth size. The length would be easy as the center cell straight down the axis will give you the length of the horn. Plug those numbers into whatever software you are using and it should give the proper results. I am not familiar with the hornresp software and haven't looked it up. Is that freeware or is this a purchased software program? I have never needed much more than a calculator and a piece of paper and a good understanding of what you are trying to achieve. Until you get into the other aspects such as dispersion angles and how you are going to create a specific dispersion angle in something like a radial horn then things do stay rather simple. It has been years since I have seen anyone use a multicell in anything that I have been around, I did move these horns many times in the olden days doing concert sound but that was long ago. I think that I know someone here in California who probably still has some of these in storage if he hasn't sold them all off. I'm still not sure why this is the direction you are following for a hifi system in a small room but you must all have some sonic quality that you like here. I still have old 511 horns in the living room in some old Barcelona enclosures with surprise to me at the time they came with air suspension 15" drivers. I thought that they would have the A7 drivers in them and was very surprised how good they actually sounded at the time.
As they are multi-cell, they don't go all the way back to the driver - see photos a few pages back. The cells terminate in a group/cluster where they go into a throat, then to the driver.
The reason to measure is for verification and as a guide to know we have the right flare. I don't think it matters too much the actual throat size or mouth size, as long as you divide it up from the overall size. In the case of the 1005, each cell is 160mm wide and high at the mouth. All 10 together seem to give the horn a cut-off around 360Hz. At least that's where response drops and distortion rises rapidly. I cross an octave above that.
The multi-cell horns are far, far better sonically than the 811 or 511 horns. Not in the same league, really. They have their faults, for sure, but I feel the advantages far outweigh the faults. It is a crazy project to build one from scratch, but that what the hobby is all about.
The reason to measure is for verification and as a guide to know we have the right flare. I don't think it matters too much the actual throat size or mouth size, as long as you divide it up from the overall size. In the case of the 1005, each cell is 160mm wide and high at the mouth. All 10 together seem to give the horn a cut-off around 360Hz. At least that's where response drops and distortion rises rapidly. I cross an octave above that.
The multi-cell horns are far, far better sonically than the 811 or 511 horns. Not in the same league, really. They have their faults, for sure, but I feel the advantages far outweigh the faults. It is a crazy project to build one from scratch, but that what the hobby is all about.
Ah ha! I think I've got it. Got Hornresp to calculate an exponential horn of 400mm length, mouth 160mm wide, throat 20mm wide. Seems to match pretty well with what I measured.
Just guessing on the throat size, but it is probably close.
XLS file included below. First two columns on the left are the important data.
Just guessing on the throat size, but it is probably close.
XLS file included below. First two columns on the left are the important data.
No problemo. I just realized that after inputting the values that when you hit enter it then displays F12, AT, Cir, so if all you want is to see these it's not necessary to go any further:
To generate a single segment horn profile, all you need do is follow the HELP’s instructions for Horn Parameters S1, S2, L12, T. All the other field’s values are irrelevant!
F12 displays Fc.
AT displays the throat’s half angle in degrees if you want to know how it lines up with a driver’s exit angle.
Cir displays the percentage of mouth area to a full size horn based on the local boundary loading specified in the Ang field.
Click Calculate.
Click Window/Schematic Diagram in the taskbar.
Click File/Export/horn data in the taskbar to pop up the Export Horn Data window. Scroll down to this section of HELP if you have any problem figuring it out.
Once any changes are done [if any], clicking OK pops up a window to save it as a txt or csv file [you choose], which can then be opened in an appropriate program to view all the horn’s dimensions at whatever expansion distance specified and/or generate a drawing to print out templates.
GM
Attachments
![1005 horn cell design [HR input].gif](/community/data/attachments/292/292505-f76f3946d5147103146ad15eab0b13f0.jpg)
Right, hornresp does give the 1/2 dims, but I doubled them in another column to check against my measurements. The flare does seem a little different at places, but I doubt it will matter. Shootz, might even be better!
EDIT: JRKO, I took your graph and overlaid it onto the photo of my horns, both the 803 and the 1005. It matches perfectly. So there you go!
EDIT: JRKO, I took your graph and overlaid it onto the photo of my horns, both the 803 and the 1005. It matches perfectly. So there you go!
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