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Re: Simplexx 212 build w/ Pics
Posted: Wed Mar 14, 2018 10:09 pm
by CoronaOperator
Electric Wisdom wrote: ↑Wed Mar 14, 2018 3:44 pm
Ah ok that calculator is like a recommendation startpoint then, i get it thanks
But the caps for tweeters are not close to the values on that calculator isnt it?
The other ones seems close tho
Crossover design is an entire discipline in and of itself. Part science, part art.
For example, your 8 ohm woofer is not 8 ohms. Look at the specification sheet for the 3012HO. The impedance in free air varies from a low of about 7 ohms, up to a high of about 120 ohms depending on frequency. Once you put that driver in a box that impedance changes depending on the box design. When you design a filter you take into account the actual impedance of the woofer/box system at the frequency that you want to crossover. Again that is your starting point and you fine tune to taste after that. You can't just enter 8 ohms into a crossover calculator and get a great result because your driver won't be 8 ohms at the frequency where you want to crossover.
The tweeter array in the simplex is also a 4th order crossover which will have very different cap values than the 2nd order crossover on that page you are looking at.
There are also different crossover types, there are Bessel, LR, Butterworth, etc. Each type will have different cap and inductor values to get the desired slope and phase response.
Also, doing the above doesn't guarantee great results. You need to look at the phase responses of the woofer and the tweeter after your crossovers to make sure that they play well with each other and take into account any lobing that might happen. Designing crossovers is very involving and makes or breaks your design. A simple calculator doesn't cut it in a good design.
Re: Simplexx 212 build w/ Pics
Posted: Wed Mar 14, 2018 11:48 pm
by Electric Wisdom
CoronaOperator wrote: ↑Wed Mar 14, 2018 10:09 pm
Electric Wisdom wrote: ↑Wed Mar 14, 2018 3:44 pm
Ah ok that calculator is like a recommendation startpoint then, i get it thanks
But the caps for tweeters are not close to the values on that calculator isnt it?
The other ones seems close tho
Crossover design is an entire discipline in and of itself. Part science, part art.
For example, your 8 ohm woofer is not 8 ohms. Look at the specification sheet for the 3012HO. The impedance in free air varies from a low of about 7 ohms, up to a high of about 120 ohms depending on frequency. Once you put that driver in a box that impedance changes depending on the box design. When you design a filter you take into account the actual impedance of the woofer/box system at the frequency that you want to crossover. Again that is your starting point and you fine tune to taste after that. You can't just enter 8 ohms into a crossover calculator and get a great result because your driver won't be 8 ohms at the frequency where you want to crossover.
The tweeter array in the simplex is also a 4th order crossover which will have very different cap values than the 2nd order crossover on that page you are looking at.
There are also different crossover types, there are Bessel, LR, Butterworth, etc. Each type will have different cap and inductor values to get the desired slope and phase response.
Also, doing the above doesn't guarantee great results. You need to look at the phase responses of the woofer and the tweeter after your crossovers to make sure that they play well with each other and take into account any lobing that might happen. Designing crossovers is very involving and makes or breaks your design. A simple calculator doesn't cut it in a good design.
Oh yeah right, i forgot about the ohm not being the same at different freq, that makes perfect sense thank you
But then what is this calculator used for in real life?
And about the phase response, if i follow the design for simplex 212, all drivers well secured on the baffle there will have no phase problems right?
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 3:45 am
by Grant Bunter
Electric Wisdom wrote: ↑Wed Mar 14, 2018 11:48 pm
And about the phase response, if i follow the design for simplex 212, all drivers well secured on the baffle there will have no phase problems right?
Right.
Bill addresses so many things in the design stage of his cabs that so many people are unaware of.
Phase response is one of those things...
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 5:16 am
by CoronaOperator
Electric Wisdom wrote: ↑Wed Mar 14, 2018 11:48 pm
But then what is this calculator used for in real life?
Same reason you had to learn about taking home the recorder! To learn about music!
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 11:54 am
by Electric Wisdom
CoronaOperator wrote: ↑Thu Mar 15, 2018 5:16 am
Electric Wisdom wrote: ↑Wed Mar 14, 2018 11:48 pm
But then what is this calculator used for in real life?
Same reason you had to learn about taking home the recorder! To learn about music!
I'm french, what this means? "taking home the recorder!"
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 11:55 am
by Electric Wisdom
Grant Bunter wrote: ↑Thu Mar 15, 2018 3:45 am
Electric Wisdom wrote: ↑Wed Mar 14, 2018 11:48 pm
And about the phase response, if i follow the design for simplex 212, all drivers well secured on the baffle there will have no phase problems right?
Right.
Bill addresses so many things in the design stage of his cabs that so many people are unaware of.
Phase response is one of those things...
I'm aware of what is phase problems, also in daw when recording drums, same concept, just wanted to confirm since both drivers are on the baffle at the same place but one higher.
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 11:56 am
by Electric Wisdom
Electric Wisdom wrote: ↑Thu Mar 15, 2018 11:55 am
Grant Bunter wrote: ↑Thu Mar 15, 2018 3:45 am
Electric Wisdom wrote: ↑Wed Mar 14, 2018 11:48 pm
And about the phase response, if i follow the design for simplex 212, all drivers well secured on the baffle there will have no phase problems right?
Right.
Bill addresses so many things in the design stage of his cabs that so many people are unaware of.
Phase response is one of those things...
I'm aware of what is phase problems, also in daw when recording drums, same concept, just wanted to confirm since both drivers are on the baffle at the same place in axis but one is higher.
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 1:20 pm
by Bill Fitzmaurice
Electric Wisdom wrote: ↑Thu Mar 15, 2018 11:54 am
I'm french, what this means? "taking home the recorder!"
America's answer to the bagpipes:
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 2:40 pm
by Electric Wisdom
Bill Fitzmaurice wrote: ↑Thu Mar 15, 2018 1:20 pm
Electric Wisdom wrote: ↑Thu Mar 15, 2018 11:54 am
I'm french, what this means? "taking home the recorder!"
America's answer to the bagpipes:
haha omg you guys lost me haha
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 4:26 pm
by Electric Wisdom
So it uses 3012lf, datasheet says 11.06" hole in the baffle right?
Because i did that at exactly 11.06" and when fitting the speaking in the hole i can move it around a bit in the hole, it's normal that it is a bit bigger than a perfect fit?
Thanks!
Re: Simplexx 212 build w/ Pics
Posted: Thu Mar 15, 2018 7:42 pm
by Electric Wisdom
The back is 1/8 off on one side but i'll sand it to make it good, hoping the baffle will fit inside, i did a fit test, seems good but let's see tomorow.
Re: Simplexx 212 build w/ Pics
Posted: Fri Mar 16, 2018 10:15 pm
by Electric Wisdom
It's all dry now. Damn that glue is super strong haha
Re: Simplexx 212 build w/ Pics
Posted: Sun Mar 18, 2018 3:13 pm
by Electric Wisdom
Ok it's completely wrong compared to the workflow on the build guide but my helper suggested installing the back first so yea i had to measure everything to the end reversed, looks like it fits well tho... i won't be as easily distracted for the second cab loll #RULE1 haha
Re: Simplexx 212 build w/ Pics
Posted: Sun Mar 18, 2018 9:35 pm
by Tom Smit
There is a reason to do the baffle first, but, it looks like you found a way around that judging by the pencil marks on the back panel.
Re: Simplexx 212 build w/ Pics
Posted: Mon Mar 19, 2018 7:11 am
by Bill Fitzmaurice
There's another reason. Doing the baffle first you can see the joints of the baffle and ducts. It's critical that they be airtight. Now when he attaches the baffle he can't tell if they're airtight, unless he happens to have a gooseneck mounted camera to look inside the cab. He'll also have to install the damping working through the speaker holes, a royal PITA.
It's a good idea to ignore advice from 'helpers'.
