Easy Horn Spreadsheet for Dummies

Here is an Excel spreadsheet that will help you design a few different things in Hornresp. It will model a single/multiple driver horn in TH, Nd, and OD configurations, in 3 or 4 sections. It will also do a BP type of quarter-wave resonator, and a T-TQWT.

The following few posts will show how to use the program, and what to expect.


Before I forget, let's thank Marshal Leach, Richard Long, and Tom Danley. They did all the real work.
The majority of the math I used can be found here: http://users.ece.gatech.edu/~mleach/.../HornPaper.pdf
Thanks go out to David McBean as well. Without his program there would be no need for this.




The Open Office file is a little outdated, but I hope to have it updated to the current build soon.

 

Easy Horn v8ca1 Excel.zip 37.216796875k . file

 

Easy Horn v5c OpenOffice.zip 40.0634765625k . file

I tried to make the program as easy to use as possible. To that end all cells that the user can change are colored yellow. All normal outputs are light blue cells with dark blue writing.

Everything you generally need to use the program is shown in the picture in the first post. I tried to centrally locate as much functionality as possible.

The first thing you want to do is to input the needed Driver parameters. You can find these cells here:


You can use the dropdown menu to pick a previously saved Driver, or enter a new Driver by filling in the yellow cells. There are around 60 driver pre-entered into the Data Bass right now. You can then click the Save Driver button to save it into the sheet. If you need to change something just alter the yellow cell in question. If you want to save the new change, just click the Save Driver/Changes button again.

If you scroll down some you will find a new area to enter even more Driver info. It is partly there to allow you to create a detailed driver data base for your own use, and some of the info will be needed in future updates.


Some have found the parameter inputs a little lacking, as there are some major parameters not input. The reason for this is that the sheet calculates them to the right of the main section for you.

Now it is time to start setting up the enclosure. This is done here:


All three input can be input manually, or you can input two and calculate the third.

The first parameter is the Horn Flare. The is the "m" parameter from the Leach paper. It determines the rate of change of the horns area as it moves between the throat and mouth. The specified range to the right is the range in which the Reactance Annulling math should be correct. As you get further way from this range it gets less accurate. This is were Hornresp would be used to alter things slightly to pull things back inline.

The Low Corner -3dB is just what you thing it is. This is the -3dB point below the Low Corner. It is most accurate with THs, as that is what everything is geared for. With the other alignments you will find the LC a little below this figure.

High Cutoff Freq. is the -3dB figure on the high side. This pertains to the horn loading, so is more inline with power response.

Below these three you see two cells named fL and fO. These are used to set the horns Reactance Annulment. fL is based off you Low Corner. You alter the Horn Flare and High Cutoff to adjust fO to equal fL as close as you feel is needed.

Further down you will find two buttons, Find Flare and Find HC Freq. Find Flare takes the LC and HC you input above, and finds the Horn Flare that fits them. Find HC Freq uses the LC and Horn Flare to find the correct HC for the pair.

It's now time to start looking at the enclosure outputs (Hornresp Inputs.)


If you notice the default Horn Flare Profile in the center is None. This is a hold over from the first versions of the sheet. It was designed to allow you to get into the Loudspeaker Wizard as fast as possible, and as such it gives you 1's in the cells that HR will auto calculate for you from the others. The new version of HR may have me taking this option out.

You can change this by clicking into the None cell. This will allow you to pick the Hornresp Con, Exp, or Par options.


If you look back to the left at the Compression cells, and it is higher than you want it (or lower,) you can also click on the None there to engage the Compression Override. This will alter the horn parameters for you.


The Vented Sub outputs are there for a quick comparison/reality check on your horns in Hornresp.

The Custom HYP Flare Calc is there to allow you to pick your own distances between point with the Length parameter. It allows you to enter a Width, and outputs a Height as well if you want to do some thing outside of Hornresp.

Sometimes you can get something like this to happen:


It happens when you start trying to tune an enclosure with a high LC Freq.

If you are doing a Nd/Od horn just input the parameters, and move on.

If you are after a TH the horn cutoff is too high, and the physical horn path is not long enough to place the Rear Tap the right distance from the throat. If you really want to make this combo work you will have to input it "as is" in Hornresp, and play with the Loudspeaker Wizard.

In the T-TQWT you can just substitute 1cm for the negative number. I'll have it automatically do that in a future update.

The Vented Sub is just tuned too high for the enclosure space.

The 1/4 Wavelength Horn is always good.

For comparisons sake here is a sealed, and vented FR graph for a pair of 35l enclosures (not including the port area.)

Just a note...

If you are expecting something like this:



and you end up with this:


The compression is to high for that driver. 2 is too much for some.

The really raised Low Corner, and it's thick triangle shape is a dead giveaway.

On the flip side, go to low and you will get this.


This is not a normal occurrence though.

Added the T-TQWR, so v4 is in the OP.

Your HC is giving you a negative in C20, and the VB script will not reach "zero" with the negative number is all it is.

Just click "end" to close the window (no needed to debug,) and put 163 in as the HC.

This is a driver that wants a higher compression horn, which may be more than it can handle. Once input, and with Horn-S2 Variable on you can raise S1 to get it into a more driver friendly range.

Thanks for the confirmation.

None of my optics sheets ever work in OOffice if I've used any VB, so I assumed this would be the same. Good to know.

EDIT: From v5 on you get .10 not negatives. There is no real fix for a TH, you need to change things. If doing a ND/Od use the 1/4WL HYP horn parameters.

If you end up with a negative in the last segment length don't worry (anywhere else is a problem,) this is what you do...

With a TH...
Enter everything in, and input the negative number as ".1" Now when you enter the Wizard with the Horn-S2 Variable on increase the last segment until it equals L12. The end of the horn will be a little off, but close.

With an Nd/OD...
Enter everything in, and input the negative number as ".1" and that's it. Same end problem as above.

Later, when the enclosure/cut sheet portion is done, I'll fix this to work automatically.

I've been getting some questions about why you would use a 4 Section horn, it's a bit tough to explain. The simple answer is that you can get a better horn that way.

It seems like it would make folding a pain, but not really. If you look you will see that I have the third section length tied to the drivers diameter. All you have to do is fold from the mouth, and use the last two section to define your depth.

He is a pic from Brain Steele's Stepped TH spreadsheet to help the explanation out: http://www.diysubwoofers.org/misc/Stepped-TH.zip


If your rear tap point was further in than the front one from the throat by much, you just turn the throat around to fire to the right first, instead of the left as seen in the pic.

You can also still do the long folds, you just have to add in some filler wood to part of the longest fold.

Thanks, I hope someone will get some use out of it.

I've had it on the back burner for a year now. Brain's sheet gave me the kick start to finish it up. I had been trying to figure out how to automate the stepped conversion for awhile with nothing, and one day there it was. He added in my path length protocols, and that got the fires going again. Now to mix it all together...

You really want to make them match if you can, and you should be able too. As long as the whole numbers match you should be good.

It isn't the end of the world if it doesn't, it will still sim fine enough it they don't match, but the devil's in the details.

There is complete reactance annulling with the original Hyperbolic flare in the horns. (The BP, and T-TQWRs need tweaking for personal preference.) That is what you are setting when matching up the two blue cells. When you section it up, and use CON, PAR, or EXP it alters things a little. That is why some driver/horn combos hold it better than others.

The section lengths are determined for the most efficient/easy 4 Section TH folding, and aren't at the very best positions for the transformation from HYP either. If you sim them up as a single flare HYP Nd horn you can check it out. The cut off will sim .1Hz higher in HR as it uses 344m/s, and I used 343m/s. If you sim for driver in HR and use the HC, and left blue cell it will pull up the same front and rear chamber within 1%, if you had figured out the ideal setup. I just checked, and the default horn pulls up with an "m/T" of .5, so I was close.

The whole idea is to have the horns pretty much good to go out of the box, with minimal tweaking needed. Glad to hear someone else appreciates the ease.

It's in the works. It will take a little time though.

I had some free time this week, and thought I would push to get the horn design portion pretty much done, and get it out to see if anything funny happens. Another idea was as you mentioned, it takes a little while to get accustomed to a new tool/program. By the time the rest is ready there will be a few people accustomed to the sheet, and they will be able to move right into the whole thing without missing a step.

Right now I'm working on adding a driver database, thinking of adding Nd/OD sections based on the Keele figures for those inclined, and starting to layout the new format where everything can work together. At the same time working on defining the parameters of the fold types I intend to include.

Actually, I'm having fun.

Please keep asking questions, and posting anything that seems off. Questions, comments, and criticisms are very welcome.

I just updated the OP with the new v5.



I just finished an overhaul, and removed a lot of old cells, and code that were hold overs from other versions. I also redid a little to streamline things, and re-tweaked the Rear Tap equation constants. The second page now includes a box to alter the Speed of Sound used, and a section that will allow you to enter your own length, and width into the horn profile generator.

I also fixed a condition that could give a negative last segment length, so it shouldn't happen anymore.

You will notice the new version gives a slightly different output than the last. This is due to the new SoS, and a better mouth correction.

As always questions, comments, bug reports, and criticisms are welcome.