Am I on the right track? Bookshelf speaker Fountek FW146 / Dayton DC28F

[crossbound]

Response curve take two. Once PCD was set up for a Parallel 2-way a few things made better sense. Adding a second capacitor in parallel (and a resistor) helped to drop down the woofer frequencies plagued by the break up to around 55db. Is that an acceptable value?

[isaeagle4031]

Not bad, but you maybe able to drop a few components and get an even better response and phase alignment. Go 2nd order on the woofer. Leave the inductor section blank. Then on the components in series before the driver, add in an lcr circuit. Set the inductor for whatever you would have put into the upper L1 section, add a .33 to .47cap, and then enter 999999999 in the resistor. You will be able to get rid of the cap and resistor zobel as well.

[WernerM]

+1
Also look at your reverse null at the crossover point. The better the phase alignment the null will get deeper. Just swap the tweeter polarity to see this and then set it as an overlay.

Did you do BSC on these?

[crossbound]

I started wondering if there would be a way to reduce the amount of components. :-) I will look into your suggestion isaeagle

Marc, sorry for pleading ignorance here for a moment. Is the reverse null the point where the tweeter and woofer response curves cross?
Also I assume BSC stands for baffle step compensation?! No I did not determine the BSC yet. Started playing with the Edge software last night, but not sure what I'm really looking at or what values to use. I realize my response curve will have to change some when I have this figured out.
Oh so much to learn.

[scottvalentin]

For diffraction and baffle step, you can use Jeff Bagby's Response Modeler software. This will also allow you to get the minimum phase files to plug into PCD. There was a thread not long ago regarding minimum phase and what it is, but honestly it was over my head!

For baffle step and diffraction, take your FRD files and import into response modeler. At the bottom of the main page is the baffle and diffraction calc area, so you can plug in your baffle width and driver locations, then transfer that curve up to the FRD response. From there, you save that file as the simmed response. Then, hit the extract minimum phase button and select the file you just saved, and this will give you an FRD file with the best phase information to then plug into PCD, along with the baffle step and diffraction effects included.

Paul Carmody's site gives a very good step by step on this here :https://sites.google.com/site/undefi...d-measurements

[isaeagle4031]

Yeah you want to have the baffle sim and min phase files to use in pcd first. Otherwise, your response curve is anything but accurate. I assumed you had already done that.

[crossbound]

One of the reasons why I didn't do the BSC yet was the fact that i couldn't get response modeler to work on my computer. I don't remember what the error was. I did some research few days back and there were other people with the same problem, but no one seemed to have a solution. I'll go and try to get response modeler to work the next few days and then I'll update my progress.

I did read through Paul's tutorial up the the point where I couldn't get the response modeler to work :-)

[wogg]

I started wondering if there would be a way to reduce the amount of components. :-) I will look into your suggestion isaeagle

Marc, sorry for pleading ignorance here for a moment. Is the reverse null the point where the tweeter and woofer response curves cross?
Also I assume BSC stands for baffle step compensation?! No I did not determine the BSC yet. Started playing with the Edge software last night, but not sure what I'm really looking at or what values to use. I realize my response curve will have to change some when I have this figured out.
Oh so much to learn.

The few times I've run through this exercise, I've completely wiped PCD and started again a couple times in order to try again with fewer parts counts. I usually end up getting there on the second or third try, granted I'm not super experience at this either so... FWIW. You appear to be doing a great job so far.

You've already mentioned trying Response Modeler with no luck on your PC. Perhaps we can help with that bit, it's really a comprehensive tool to nail the BSC and diffraction into the response curves. What errors are you getting when you try to open it, what Office version do you have etc.

The process should flow like this:
Source FRD / ZMA -> Response Modeler
Add cabinet and baffle arrangements, merge them to the response curve, export modeled FRD / ZMA files. Then use the extract minimum phase buttons and save out your FRD / ZMA files as fully "simmed" files.
Min Phase files -> PCD
Build filters, get too many parts, clear, repeat

Not bad, but you maybe able to drop a few components and get an even better response and phase alignment. Go 2nd order on the woofer. Leave the inductor section blank. Then on the components in series before the driver, add in an lcr circuit. Set the inductor for whatever you would have put into the upper L1 section, add a .33 to .47cap, and then enter 999999999 in the resistor. You will be able to get rid of the cap and resistor zobel as well.

That's exactly what I was talking about earlier with the cap parallel with the inductor in the woofer low pass. This creates a tank notch filter.

[scottvalentin]

I see - did you ensure that all of add-ins in excel were turned on? Analysis Toolpak - VBA are the ones you need.

[WernerM]

One of the reasons why I didn't do the BSC yet was the fact that i couldn't get response modeler to work on my computer. I don't remember what the error was. I did some research few days back and there were other people with the same problem, but no one seemed to have a solution. I'll go and try to get response modeler to work the next few days and then I'll update my progress.

I did read through Paul's tutorial up the the point where I couldn't get the response modeler to work :-)

Initially when I first started simming a few years ago it didn't work for me either, I ended up reinstalling it and that worked.

When I say reverse null, I mean the major dip/valley that is created in the summed FR at the crossover frequency. It happens when both drivers are playing the same frequency in the same phase and they cancel each other out. This is why we usually end up running revered polarity on tweeters. If you reverse the polarity in your sim you should see this suckout at the crossover point.

[crossbound]

Here are two screen shots with errors.. one says
- compile error in hidden modul: ThisWorkbook

the other
- compile error in hidden modul: cGlobal

I do have Analysis Toolpak and Analysis Toolpak - VBA installed since they are required for PCD as well
And I'm running Excel 2010 on Windows 10 Pro 64-bit

[WernerM]

Look in my TMWW thread in my signature page 32 post 468 for an example. The grey fr curve is the overlay showing the reverse null. That thread is a lot to sift through, but to me has some excellent tips and instructions from the more experienced designers on here.

[crossbound]

Thanks Marc for the explanation on the reverse null. There is just so much terminology and processes in designing speakers.. It takes a little to wrap my head around it.

[wogg]

Is your office installation 64bit as well? The 32bit Office should work fine on that system. I've had many instances of VB code failing when a user has 64bit office installed.

[crossbound]

Yes I was running Excel in 64-bit. Dug out my old copy of Excel 32-bit and that did the trick.. no more error messages.