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soho54 11-26-10 05:09 PM

Hornresp for Dum... hmm... Everyone ;)

I just noticed there isn't a real How-To Manual on Hornresp anywhere. There are some guides on how to do so and so using HR, but not a Hornresp basics primer. Guess it's time.

Hornresp is a speaker modeling program by David McBean. It started off a few decades ago as a horn modeling program with punch card data inputs. Yes, it is that old, ;) Luckily for us, the program was continuously updated from the beginning, and is now a very capable tool for much more than just traditional horns. There have been several major additions over the last year which really helps with the programs usability for those just starting out, and as such it has become extremely popular. The new Wizard function is the star attraction now, as it allows you to view the changes you are making in real time. I'm going to try to touch on a few of the possible ways to use the program here, and try to explain the functionality of the programs many different options.

You can download the latest version of the program from David McBean's site:http://www.hornresp.net.ms/

The next few posts will explain the basic functions of the program, followed by practical examples, with example specific special options. You can use the following links to skip to another area faster if you wish, and to find new additions if/when thread creep sets in. As always, questions and comments are welcome.

Sealed Enclosures
Vented Enclosures (Simple)
Vented Enclosures (Alternate Method)
Normal Horns (Single)
Normal Horns (Multi-Segmented)
Offset Driver Horns
Tapped Horns
Rear Loaded Horns
Compound Horns
Bandpass Enclosures
IB Setups

All examples will use the CSS Trio12 to simplify things. The factory data is from here: http://www.creativesound.ca/pdf/CSS-...ata-051009.pdf

soho54 11-26-10 05:10 PM

This is the main screen.


I'm going to take some time, and go through all the functionality first, and then show a few examples of how to do sealed, vented, and some different types of horn subs. Feel free to jump ahead it you, "don't need no stinking instructions." It will be here to come back to if you get lost. :D

First, I must point out that almost everything on this screen can be double clicked to alter it, or pull up another window to input options. Text, and input blocks alike. I won't go into all the different ways to input things, but you will want to play with this some to see what is there.

In order to play with the settings you will need to click Add to start your first session, and then click Edit to alter anything.

Top Half________________
  • Ang is the radiation angle. This is simply the amount of nearby boundaries. It is normally referenced to a "space" parameter. Free Space (Ang=4.00) is the speaker hoisted in the air, and as such has no boundaries nearby. Half Space (Ang=2.00) is the spacer placed on one boundary such as a speaker setting on the ground in the middle of a field. This is the default setting for most all other simulators (WinISD, Unibox...) Quarter Space (Ang=1.00) has two boundaries. Say a sub sitting on the floor pushed up against a wall as well. Eighth Space (Ang=0.50) this is a corner placement, with three boundaries. Hornresp also has one more setting this is Infinite Horn (Ang=0.00) which is only useful when working with horn theory, and ideal horns.

    There is a tendency for people to say, "Well, I'm putting the enclosure in a corner, so I should use 8th Space." This is not quite right though. Unless you are building a horn with a mouth so large that it takes up the whole corner from floor to ceiling. You will get an overly optimistic FR with anything else, so it is best not to use it. If you plan on comparing the Hornresp graph to sims from other programs you will want to use Half Space (Ang=2.0)

  • Eg is the Voltage you are testing at. Most people are use to inputting/thinking in Wattage, but Wattage changes with frequency in a speaker. Voltage is a more precise method of metering the power in. You can do a fast general conversion to Watts with (Voltage*Voltage)/Re. (HR has a calculator for this. Can you double click, and find it?)

  • Rg is the extra resistance from the amplifier and the wires you are using. You can leave this at 0 for the most part, unless you are going to be using a tube amp. 0.08 is a good start for most pro amps, and 6-12ft of wire.

  • S1-S5 are possible cross sectional area inputs you may or may not use.

  • The four blocks under Rg are the length inputs for the S# sections to the left of each. They are L12, L23, L34, and L45 from top to bottom. Here the top two blocks are used. If you double click the "L12" you can activate the block. Multiple click changes the "L12" into Con, Exp, and then Par (I'll get to these in a bit.) If you input a number into the block it will lock it in. If you click on something else without entering a distance the cell deactivates, and returns to L12. This also deactivates anything after it as well.

  • The Cir and F#s are the horn mouth area cut off frequency, and/or horn segment flare angles. They are there for your information, if you need to know such things.

Bottom Half_____________
  • Sd, Cms, Mmd, Re, Bl, Rms, and Le are the driver parameter inputs. You want to enter Sd, Re, and Le first. The other parameters Hornresp will calculate for you by double clicking the blocks, and entering the required info. I do them in order as well, so Cms, Mmd, Bl, and then Rms. You will need the common parameters Vas, Fs, Qes, and Qms to calculate them.

  • The Nd sets the programs simulation options. I'll get to this a little later. The block next to it is the number of drivers in the system. If you double click it, a window will open up allowing you to set the number of parallel, and series drivers.

The last six blocks will require another post. ;)

soho54 11-26-10 05:11 PM

Ok, here are the last six blocks again.

Vrc is the volume of any rear chamber/space the driver is attached to.

Lrc is the length of the rear of the chamber from the driver, or the depth of the chamber.
Nd is setup with a sealed rear chamber by default, as it is here. It allows you to line the rear walls, and that is what the next two blocks are for.
Fr is the airflow resistance measurement for the lining material. It is in rayls/cm, and can be found on material data sheets online, for a variety of materials.

Tal is simply the thickness of the lining you are adding.

Vtc and Atc define a throat chamber. You can also think of it as a front chamber area. It is not sealed, but you can do a lot of things with it, with more than just horns.
Now up top in the Tools tab you can change the sealed rear chamber to something else. Let's create a vented rear chamber.

Now we get this:
Fr & Tal are now Ap & Lpt
Ap is the cross-sectional area of the port, and Lpt is the length of the port.
Let's try that third option out now.

Throat Adapter? What has changed?
Now we have Ap1 & Lpt. This a chamber/section in front of the throat chamber. If you have seen horns where the opening between the driver and the horn is smaller than the cones diameter that is what this is. Ap1 is the area of the opening, and Lpt is the thickness of the wood most of the time.
If you are using OD the Throat Adapter is called a Throat Port. It serves the same purpose.

Here is a graphic illustration of the Vtc/Atc - Ap1/Lpt concepts, as they pertain to horns.

soho54 11-26-10 05:11 PM

Hornresp has many graphing options available after you Calculate a design.

You can find them in the Window tab up top. If you go to the Tools>Options tab will can select the first graph to pop up after you hit Calculate, if you don't care to see the Schematic pop up every time. I use SPL Response myself. ;)

Schematic Diagram
This shows the basic layout of the enclosure you have designed. You can move your mouse over it to display information about each enclosure section.

Acoustical Impedance
This is important for Horns, as it shows the Reactance/Resistance at the horns throat. This is another whole topic.

SPL Response
This is the good'ole FR graph most are used to seeing.

There are also other options under this Window. If you check the Tools tab with the SPL Response up you will find an Impulse, Maximum SPL, and Multiple Speakers option. Max SPL is just what it sounds like. You enter a Wattage number, and an Xmax limit, and it shows which is hit first. The Multiple Speakers option, confuses some people. It is not a multiple drivers setting, it is a multiple enclosure setting. If you want to see the SPL of four of your simed speaker enclosures this is what you would use.
The Impulse option is broken down into two more options.
This is the Impulse response of the enclosure. Note that it isn't band limited in any way. This means if you are doing a sub, there is no way to limit it to the subs bandwidth. Artifacts above the subs bandwidth will alter the IR from what the true in use IR would be.

This is a different way to look at the IR. Frequency is listed from bottom to top, and time is from left to right. This view is more helpful to newbies as you can see the frequency spread, and can focus on the bandwidth area you need while ignoring the rest.
Electrical Impedance
You can alter the Ohm Range in the Tools tab if it is too large.

Diaphragm Displacement
This is the excursion graph.

Phase Response
This shows the system total phase, and the delay can be altered in the Tools tab, in time or distance.

Group Delay
This is another way to look at phase. With some enclosures you will get some large peaks here. These parallel FR peaks, and their Q. If you alter the FR peaks, the GD peaks will be changed as well. This is something to keep in mind before wigging out over it to bad. ;)

soho54 11-26-10 05:12 PM

Sealed Enclosures

OK, let's play with a sealed sub here.

Will will use one driver in Half Space (Ang=2.00), and 2V as the Re is 4ohm. This gives us 1W. Since we are after a sealed sub we want the Nd option. Zero everything else out.
Input the parameters as I outlined up top, and you should get this.

Now we need to enter the enclosure. If you know the enclosure size you want already just enter the volume into Vrc, and depth into Lrc. That's it, hit Calculate, and you are done. If you aren't sure exactly what you want go into the Tools tab, and start the Loudspeaker Wizard.
It will open up a new window.
Just use the Vrc and Lrc sliders to quickly get a rear chamber, and the switch over to the Response view with the drop down box at the bottom left. As you can see there are several other helpful graphs there as well.


Now you can tweak the enclosure with the sliders some more while observing the FR. :D

If you change the drop down to the right to Other, you can change the input voltage. Switch the graph to Displacement to check over excursion.

Don't let the Series Parallel sliders throw you. It says that there is one driver in series with itself, and one driver paralleled to itself. Two driver in series would be 2S-1P, Four driver in Series/Parallel would be 2S-2P.

soho54 11-26-10 05:12 PM

Vented Enclosures (Simple)

A vented sub is done just like a sealed sub, only you switch on the Rear Vented option in the Tools> Chamber tab. The only limitation is that it only allows for a single port at this time.

Will will use a Vrc of 50, and Lrc of 30.1 from the sealed example above. You should start from here:

OK, if you know your desired port dimensions enter them into the Ap and Lpt blocks, and Calculate. If you are unsure of that now start the Loudspeaker Wizard up, and play with the Ap and Lpt sliders while looking at the Response graph, until you like what you see. You will need to change the third dropdown bow from default to Combined here. Default with give you the Driver output only, Output 2 is the port only, and Combined is both. ;)
I want you to really look at the pic above. Hornresp shows large peaks, and dips that you may not be use to seeing. These are the resonances caused by the main enclosure area, and the port. The peaks are exaggerated here as the program assumes totally solid materials. In real life the peaks and dips will not be as extreme, but they will be there in some fashion.

When you like what you see save it, and the Calculate. When you open the SPL Response up it will default to the Default graph of the driver only.

To change it go to Tools>Combined Response

A new window will pop up.

This is to set the amount of difference from your ears to the port mouth from the driver. The window does a good job of telling you how to do it, so follow the directions, or just leave it as 0.


soho54 11-26-10 05:13 PM

Vented Enclosures (Alternate Method)

Here is an alternate way to sim a vented enclosure. The goal here is to get you thinking out of the box.

In the last example we ended up with a rear enclosure of 50l 30.1cm deep, with a 200cm2 port 165cm long.

All we have to do is move everything around to the other side of the driver. The port can be entered as S1 & S2 as 200, with L12 input as 165. The flare type doesn't matter here as there is no flare, so just leave it as Con.

Now the main enclosure is input as the Throat Chamber. Enter the Vtc as 50000 (as it ic cc here, and not liters,) and the Atc requires a little math. All chambers are cylinders here, so you have the height and volume, but need the area of the top or bottom. Math skip... enter 1661.129 for Atc. ;)


Notice the Schematic is flipped around here.

soho54 11-26-10 05:14 PM

Normal Horns (Single)

This is Hornresp's main function, simulating horns. It has a wide assortment of different horn types to chose from, as seen here:

You can get to this window by selecting the Nd setting, blacking out all data in S1-S5 & L12-L45, and double clicking the L12 input block.

All of these horn types are a little different, and will alter the Cir & F# cells to allow you to work with the different profiles. All but Conical, Exponential, and Parabolic can only be used as a single segment horn.

They all follow the same basic profile as shown in the picture below. Ap1/Lpt and Atc/Vtc can be left out if they are not needed, but the rest will be needed for every Nd front loaded horn.

I will go over the Hyperbolic flare horn design work flow here as an example. Start off with a blank slate, and select the HYP flare parameter by either double clicking the L12 block, and choosing form the list, or clicking the L12 block and pressing the "H" key.

Now just enter a number into the L12 block, say 500 to lock the HYP profile in.

You must now input a preliminary horn. Take the Sd/2 and enter it as S1. Then take the Sdx10 as the S2.

If you look at the Cir parameter it now says ".24" This is the distance of the parameter circumference of the S2 mouth when compared to the horns cutoff frequencies wavelength. I this case the mouth circumference is only .24 or 24% of the cutoffs WL.

The frequency cutoff in Hz is given by F12. This is the frequency at which your horn stops loading the driver.

Notice the red "Caution" that popped up. It is telling you that your driver will not mate up the the horn as it is. This means you need to add a Throat Adapter, which also means a Throat Chamber is created.
Go to Tools>Chamber and select the Throat Adapter. Ap1 will be the same as S1, and Lpt will the the thickness of the wood. Let's use 1.8cm here.

The Throat Chamber is a little more tricky, but we can guesstimate. Use the drivers Sd as the Atc, and then try to figure out the distance between the drivers cone base, and the top of it's flange/gasket, then divide it by 3. Using the PDF for this driver I get ~2.72. Remember this is only a fast guess, it would be better to measure the actual dish cc. Take the guessed 2.71 x Atc, and that is Vtc. Vtc=1330.61 This is just a starting point, as the size of the Throat Chamber affects the high frequency loading of the horn.
Now a red "Note" has popped up. This is the type of hyperbolic horn you are using right now, and a reminder to input a "T". The T(it is referred to as "m" as well) is the slope profile of the horn, and is input where F23 use to be. Let's use .6 for now.

The single segment Nd horn will not allow the use of the Loudspeaker Wizard, so lets hit Calculate and check out the SPL Response. (Note: with Con, Exp, and Par you can cheat here by entering a second segment that is a sq cm more than S3, and ~1cm in length. This will allow you to enter the Wizard with no trouble.) Normally you would go ahead, and add the Rear Chamber before siming, but I want to show it's effect there.

It is a bit bumpy. Let's go back and enter a rear chamber. We will randomly use Vrc=30, Lrc=30 for now.

Then re-Calculate.

Now it is just a mater of playing with the parameters until you get the response you are after. This applies to all horn types. Each one will require different parameters to reach their potential, but that is beyond the scope of this thread. This will get you running though. :D

soho54 11-26-10 05:14 PM

Normal Horns (Multi-Segmented)

You can also do Multi-Segmented horns with the Con, Exp, and Par flare parameters.

It works exactly the same as the Single Segment Nd horns, only it does allow the Loudspeaker Wizard, so you can see the effects of your changes as you make them.

There is not a lot to add over the single section horn build. The main difference is that a "T" is not input as you are defining that yourself with the section Sd's, so I will just give you a diagram and a sample segmented horn demo here.

soho54 11-26-10 05:15 PM

Offset Driver Horns

Offset Driver horns are exactly like normal horns, only the driver is not placed at the true throat of the horn. It taps into the horn at a position further down stream from the throat.

You input and work with them in exactly the same way as a normal horn with one extra thing to check on. As the driver is not at the throat soundwaves are sent up and down the horn at the same time. This leads to cancellation issues above a frequency set by the round trip distance from the driver to the throat, and back to the driver. The longer the distance the lower the cancellation occurs.

I am supplying a general parameter placement diagram, and the input screen of the same horn from the Normal Horns(Multi-Segmented) post, converted to an OD horn. This way it can be seen how they are similar, and how the cancellation effects the higher frequencies.

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