Have a look at Dave Dal Farra's tutorial for designing with traced data (though the section on normalising and minimum phase extraction is relevant if you are using PCD with offsets and measurements that do not include relative phase offsets. http://audio.claub.net/software/DaveDalFarra/Simple%20Loudspeaker%20Design%20ver2.pdf
See the section "Prepare Woofer FRD's" for the normalization.
The section create woofer phase tells how to extract the minimum phase.
As you have measurements on the baffle, and have worked out your offsets, you don't need to worry about all the stuff for dealing with baffle step etc, unless you want to splice in nearfield measurements, or simulated response for the low frequencies.
edit: it says that the reason for interpolating is to make it easy to splice, but I'm pretty sure I found that it made quite a difference to calculated minimum phase if it was extended down to 20Hz or not.
Tony.
See the section "Prepare Woofer FRD's" for the normalization.
The section create woofer phase tells how to extract the minimum phase.
As you have measurements on the baffle, and have worked out your offsets, you don't need to worry about all the stuff for dealing with baffle step etc, unless you want to splice in nearfield measurements, or simulated response for the low frequencies.
edit: it says that the reason for interpolating is to make it easy to splice, but I'm pretty sure I found that it made quite a difference to calculated minimum phase if it was extended down to 20Hz or not.
Tony.
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Based on wintermute and bullitstangs recomendation I started at the beginning designing to the tutorial. I did have to fudge a little bit because I am using open baffle for mid and tweeter and the tweeter is an AST so I used 1.5 in dia. I started with unibox and it agrees with my original design of a sealed box 1.66 cu ft Qt=.71. The I entered my info into Boxycad and it based on the floor bounce it recommends a XO point between woofer and mid at 425hz. I currently have it at 300hz. Should I be concerned? everything else is looking consistent to what I already have. next up is response modeler. Thanks for taking the time to guide me. Happy 4th everyone 🙂
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No can do Response Modeler as I have Xcel 2010. Version is too new. Am I doing something wrong? alternatives?
Should work in excel 2010 (that's what I have)... I can't remember if I had to do anything tricky to get it working though....
Tony.
Tony.
Dave's tutorial is fairly good and gives impression for being
careful about details like subtracting IEC baffle response
but it doesn't say a newbie how to subtract that exactly.
Was that meant to be a homework exercise?
careful about details like subtracting IEC baffle response
but it doesn't say a newbie how to subtract that exactly.
Was that meant to be a homework exercise?
OK so I think I found the issue. I have a 64bit machine and the program is written to work on 32 bit machine (per microsoft) 😡
I have 64bit windows7. but I just checked and my excel 2010 is 32 bit...
It works fine in 32 bit excel... I'm a bit surprised it is not backwards compatible. you probably need a 32 bit dll, the question is which one?
regards,
Tony.
It works fine in 32 bit excel... I'm a bit surprised it is not backwards compatible. you probably need a 32 bit dll, the question is which one?
regards,
Tony.
Yep just checked. I have 64 bit office. Everything I read said that 32 bit is better for most users. Is there another program That I can extract minimum phase?
Hi again, Was away for a short vacation. While away i exchanged emails with Jeff B and he recommended I use FRD Response Blender instead of Response Modeler. Since I am doing a 3 way will this work for my project? There is a LF and HF import feature. (unless I have to do 2 iterations of it?
From memory the response blender has a minimum phase export option. I think it should be fine, if you don't add the baffle step and only load a single frd (ie don't splice anything and don't model baffle step). It should just export the minimum phase of the imported frd.
Tony.
Tony.
correcting the errors of my ways Ha!
Well, as i learn I am finding my errors. One of them had to do with seeing that some FRD and ZMA imports did persist after saving the file. I had to import again. I m fairly certain I have it right now. The only thing is on the woofer am I suppose to blend in frequency response as if it were in an enclosure? Again, you guidance is appreciated.
Well, as i learn I am finding my errors. One of them had to do with seeing that some FRD and ZMA imports did persist after saving the file. I had to import again. I m fairly certain I have it right now. The only thing is on the woofer am I suppose to blend in frequency response as if it were in an enclosure? Again, you guidance is appreciated.
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