3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

hi jeff,

thanks for that. i set to 15msec as i want to get a "true" response from 200hz where the xo between 3012LF and satori would be. i will set it accordingly, i did play with the gating, when i saw the 5msec smoother, i thought the omnimic was fooling me :D

do you have any comment on the omnimic? im getting consistent dropping for 10khz up, is this omnimic problem?

cheers
henry

[r-carpenter]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

To get a true response of your woofer and midrange you need to measure "near field" and splice to "far field response". By measuring at 1.2m at 15msc gating you aren't getting true response but rather contaminated by boundary reflections response.
Your gating should probably be around 3-4msc for far field measurements. Do you know how to calculate gating?
It's not likely that your omnimic is faulty but anything is possible.
this was my raal adventure: http://techtalk.parts-express.com/sh...g-Raal-140-15D different model mind you.

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

hi r-carpenter,

should i splice it at the point where the gating ends? lets say farfield 8msec for 500hz and nearfield for below 500hz? how about the SPL, how to match the spl between the 2 distance?

am i correct to measure it at on axis, and input the offsets at PCD to get an accurate simulation? or all done in tw axis? at least for the midrange to tweeter i mean.

cheers
henry

[r-carpenter]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

you should splice where the data is valid.
For the woofer, gate at 500msc or so and place the mic near field. Take second measurement far field and gate around 4msc (depending on near boundary position). Merge at 400hz.
Make all your far field measurements for all drivers at the same input voltage. Near field data should be SPL adjusted to the far field. Diffraction is added later on for which I am sure Jeff's PCD has a function(as well as offset of the drivers). But he's be able to answer that better. I am not familiar with PCD. All data is measured on axis to the tweeter however I would recommend taking some off axis measurements later on in the game.

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

omnimic only have max 15msec gate, do you mean 5msec?

For the woofer, gate at 500msc

so this is what i have to do for Woofer :
1. Nearfield (put the mic in front of the dustcap?) gated 5msec.
2. Farfield (2m distance? or 1.2m is good enough?) on axis of the woofer.
3. Splice at 400hz
4. Combined the nearfield and farfield.
5. Estimate the SPL with the omnimic levels (lets say determined several freq for the SPL, and match it as close as possible, since the other would be farfield gated 4msec which around 600hz, then it should be matched above 600hz.)

All data is measured on axis to the tweeter

does this means i position the mic on tweeter level and on axis for WOOFER measurements on both nearfield and farfield? or you mean that all at the same Horizontal Axis?

cheers
henry

[r-carpenter]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

omnimic only have max 15msec gate, do you mean 5msec?

so this is what i have to do for Woofer :
1. Nearfield (put the mic in front of the dustcap?) gated 5msec.
2. Farfield (2m distance? or 1.2m is good enough?) on axis of the woofer.
3. Splice at 400hz
4. Combined the nearfield and farfield.
5. Estimate the SPL with the omnimic levels (lets say determined several freq for the SPL, and match it as close as possible, since the other would be farfield gated 4msec which around 600hz, then it should be matched above 600hz.)

does this means i position the mic on tweeter level and on axis for WOOFER measurements on both nearfield and farfield? or you mean that all at the same Horizontal Axis?

cheers
henry

no.
Position mic at 1m on tweeter axis.
1)take far field for the tweeter .with 4msc gating save it.
2)take far field for the mid 4msc gating. save it
3) Take far field response of the woofer with same gating and save it.

while doing all these, do not touch the mic or volume knob so all 1m SPL of the drivers are correct in relation to each other.

4) take near field of the mid with whatever long gating Omni lets you. 200msc should do. Mic positioning for this is at 1cm from dust cup.
splice this response to the far field of the mid while adjusting relative level ONLY of the near field response. Splice the response below boundary reflection (probably around 500hz)
5) Measure near field response of the woofer (again, mic at 1cm from dust cup) and splice it to the far field. Keep the far field SPL untouched. Only adjust near field for splicing.
basically same thing as with the mid.
next would be adding diffraction and offsets in PCD which is Jeff's baby.

Henry, do you understand why gating is employed? I don't mean to sound like a .........
But it's just a very important issue.

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

its allright, im keen to learn. as i understand the gating is to delay the signal coming into the mic to reduce reflections, but im not so sure.

ok, i just realized that it is possible in omnimic to have 250msec :D

im not aware of diffraction add-on in PCD, but the offsets does changes the response. im assuming the diffraction can be captured with farfield measuremetns.

ill follow your instructions tonite and tomorrow , thanks for all the help.

cheers
henry

[r-carpenter]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

gating is not a delay. Gating the capture window allow you to basically time for how long your microphone is reading the signal.For far field measurements at 1 meter you are timing for 3msc because after that reflected signal is also captured and the data is contaminated. So, your mic is reading the signal (or rather software) for the first 3msc after the speaker is fired the MLS burst. Shorter the time slice or window that you gated, shorter the wavelength of the uncontaminated captured signal. This is why "near field" techniques and later on merging is used. Diffraction effects are fairly well understood and modeled mathematically. they are usually added later during modeling stage. These are universal laws and PCD or diffraction modeler (please correct me if I am wrong, not familiar with the software) should have an interface for it.
I wold say that at this point you probably should stop and read this: http://www.parts-express.com/pe/show...number=500-030
The modeling of the crossover is only going to be as accurate as the data that you have captured. With a nice set of pricy drivers I would recommend taking your time.

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

hi r-carpenter,

thanks for the link. im getting to understand to what i see on the omnimic when changing distance and gating. yes, i can do splicing and adding baffle step in response modeler.

im taking my time slowly for the passive, as im running active for now and eq it with minidsp. i like to try passive for simplicity reason and since i got enough power to drive them.

cheers
henry

[r-carpenter]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

is there any reason you don't want to continue with active/dsp?

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

i cant afford to buy more amps :D.
im using the ROTEL RB1075 and ncore. the rotels supposed to be for my home theater and buying another 4ch of ncore seems too much, and to top it all, it seems wasted the nice DAC i have here.

anyway, ive tried your suggestions to splice and combined, i cant do this with jeff b response modeler (or am i missing something?), it only splice 1 way, which take out either <100, <200 and <300hz, where the below that freq, i can add the bafflestep modeler and box simulated response.

i just think, since i got the measurement gear, better to use the actual measurements to combined the nearfield (mic on dustcap) and the 1m mic measurements.

What do you use usually to combine the freq?

cheers
henry

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

double post, sorry.

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

never mind for the splicing, i see the function on omnimic already.

such a powerful tool!

[henry218]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

allright,

i think i got this already





im concern about the impedance bump on 5khz, and the ugly phase. i dont know what else can i do, the phase keeps on turning 180deg.

i hope someone with more experience can chime in, ill appreciate it very much

cheers
henry

[Pete Schumacher]

Re: 3way Kappalite 3012LF + Satori 4ohm + RAAL 70-10D

allright,

i think i got this already

[ATTACH=CONFIG]38212[/ATTACH]
[ATTACH=CONFIG]38213[/ATTACH]
[ATTACH=CONFIG]38214[/ATTACH]

im concern about the impedance bump on 5khz, and the ugly phase. i dont know what else can i do, the phase keeps on turning 180deg.

i hope someone with more experience can chime in, ill appreciate it very much

cheers
henry

The phase is fine, so is the impedance. The phase wrap is a result of the crossover and acoustic slopes.

If you don't mind, flip the mid polarity and post the result to see how deep the reverse nulls are (phase tracking).