I understand. The title of the thread was FRC help not FRD help. I'll try to keep messing with it until I get it working... not. Thanks for your help, though. The tutorial is here FRD Consortium tools guide
Hey Dumptruck, sorry if I got a little touchy yesterday; I was just frustrated. I appreciate the help.
I have dropped the FRD consort. programs. After more research, I believe there is just a glitch with either the combiner or Excel. I have been playing with Jeff Bagby's modeler and PCD instead. It seems to be working great and it's much more intuitive.
One question if you don't mind. Should the impedance created by Response Modeler differ from the manufacture's provided impedance graph. Mine does and I don't know if it is altered because of the enclosure. It is more or less the same except it rises as the frequency increases.
Thanks again
Evan
I have dropped the FRD consort. programs. After more research, I believe there is just a glitch with either the combiner or Excel. I have been playing with Jeff Bagby's modeler and PCD instead. It seems to be working great and it's much more intuitive.
One question if you don't mind. Should the impedance created by Response Modeler differ from the manufacture's provided impedance graph. Mine does and I don't know if it is altered because of the enclosure. It is more or less the same except it rises as the frequency increases.
Thanks again
Evan
No problem, I wasn't ignoring you, I just tend to disappear into real life on the weekends. I haven't tried the tutorial, but it does seem like you've got some kind of glitch happening. Maybe you need a different version of Excel or something?
For the impedance, the lower frequency range will be different from the mfg's graph because of the enclosure you're modeling. Namely, the one- or two-hump shape from a given sealed enclosure or bass reflex enclosure. Above that, the modeler is going to make a guess based on the inductance information it has. When you can't measure it, you want to use the mfg. data for that range instead of the modeled data.
For the impedance, the lower frequency range will be different from the mfg's graph because of the enclosure you're modeling. Namely, the one- or two-hump shape from a given sealed enclosure or bass reflex enclosure. Above that, the modeler is going to make a guess based on the inductance information it has. When you can't measure it, you want to use the mfg. data for that range instead of the modeled data.
Hey, no problem. I used to disappear into real life on weekends a lot more than I do now
I found some info from Roman, who wrote the tutorial. He says that has happened to a lot of people and he doesn't have an answer for it.
I understand the different resonant peaks created by the enclosure. It's the rising response that's different. I can measure impedance, but I'm not sure how to import that file into Modeler or PCD. I guess I need look into that some more.
One other question. I want to rear mount the woofer in a fast system that is crossed about 400Hz. When I change the z axis for the woofer in PCD to reflect this, I get seriously reduced output from about 1Khz to 10Khz. Is this right and is it important to worry about when crossing this low where the wave from the woofer is fairly long?
Evan
I found some info from Roman, who wrote the tutorial. He says that has happened to a lot of people and he doesn't have an answer for it.
I understand the different resonant peaks created by the enclosure. It's the rising response that's different. I can measure impedance, but I'm not sure how to import that file into Modeler or PCD. I guess I need look into that some more.
One other question
. I want to rear mount the woofer in a fast system that is crossed about 400Hz. When I change the z axis for the woofer in PCD to reflect this, I get seriously reduced output from about 1Khz to 10Khz. Is this right and is it important to worry about when crossing this low where the wave from the woofer is fairly long?Evan
Actually hold on, it seems I forgot everything that modeler can do. You should be able to get it to work by importing the traced zma and then working with it to fix the low end, BUT you should just measure in-box to a zma and use that in PCD anyway, since you can. I use LIMP for that.
As for the new question, you're going to have to post files and physical distances for me to load the same stuff up in PCD or I just can't tell you. It's almost certainly coming from the simulated off-axis rolloff, one way or another, which is dictated by what you input for piston diameter. For determining the z-offset with single-axis measurements, you don't want that, and may have to input teeny tiny diameters to get the sum to line up with the measurement. After you have real z-axis offsets determined, you can try to make it as accurate as possible by inputting real piston diameters, and using frds measured on-axis with each driver, and simulating at a more reasonable listening distance.
edit: whoops, I got you confused with the guy I was helping with z-offset measurements. Umm, actually still the same answer, just ignore the stuff about measurements.
As for the new question, you're going to have to post files and physical distances for me to load the same stuff up in PCD or I just can't tell you. It's almost certainly coming from the simulated off-axis rolloff, one way or another, which is dictated by what you input for piston diameter. For determining the z-offset with single-axis measurements, you don't want that, and may have to input teeny tiny diameters to get the sum to line up with the measurement. After you have real z-axis offsets determined, you can try to make it as accurate as possible by inputting real piston diameters, and using frds measured on-axis with each driver, and simulating at a more reasonable listening distance.
edit: whoops, I got you confused with the guy I was helping with z-offset measurements. Umm, actually still the same answer, just ignore the stuff about measurements.
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To get an accurate crossover simulation, the relative z-offsets from driver to driver have to match the actual offset in acoustic centers. Sometimes guessing works fine, sometimes it's way off.
The driver diameter out to halfway across the surround is a decent approximation for piston diameter for conventional drivers. For waveguides, ribbons, etc., the off-axis simulation won't work and you just have to work around that.
The driver diameter out to halfway across the surround is a decent approximation for piston diameter for conventional drivers. For waveguides, ribbons, etc., the off-axis simulation won't work and you just have to work around that.
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