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Discussion Starter · #1 ·
Good Day Everyone, I will be attempting my first enclosure build, I am excited to see how well this goes, but first a little introduction as to how I came to this decision to build a box, I bought this sub along with a box off Amazon.
The cutout was too big when it arrived if I remember correctly something wasn't right, had to return it. Dissapointment the first feeling I felt, them found another box online never bought it to big for the car.So I said fine I just build my own. Expecting everything to be plug and play, never worked out for me, so I sat around about a month thinking what would be my next step to do with this nice Kicker sub I was once excited to just put in and play and now it's completely useless at least until it gets a proper home. So I decided to build my own. After months of research with the limited time I have from working full time, I am finally about to get building so I am happy and pretty dang proud of myself, for pushing though this far so far, and in my opinion this enclosure will be better than any prefab I could've brought online and sound better too hopefully.
(Forgot to mention up there 15s love thier space and didn't mind giving up my whole trunk, and wish I knew this before, If I knew this box was going to be long research project I would've still done it.

The box is going to be 8.01³ Gross and 6.41³ Net.
1.6 Cubes are displacements including the port, speaker bracing, plexiglass, and 45s using 3/4 MDF which brings my net volume of 6.41 back to the gross volume of 8.01.

Outer dimensions of the box will be 38x20.75x22, Will be doubled baffled.
Inner Dimensions will be 36.5x18.5x20.5
This enclosure will have a plexiglass (cast acrylic) viewing window with a chamfered 45° degree leading to to the window and the window will be below the wood with the chamfer wrapped with black vinyl and gray carpet for the outside of the box.
Dual Voice Coil 4 OHM Sub will be powered by a 1200 watt Kicker AMP wired down to 2 OHM.
Pic 2 is the transfer function of the box without filters, Thanks for reading.
World Purple Slope Font Terrestrial plant
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Rectangle Font Parallel Slope Technology

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Discussion Starter · #2 ·
If anybody sees anything wrong let me know please.

I had one question that I'm not too sure about the 45s calculation let's say a square that's 1.5 inches all around you cut it right in half makes a 45.
A 45 is just half a square?????
So the calculation is 1.5x1.5x20.5÷2÷1728=0.0133(0.01) ?????
The inside of my box is 20.5
and I divided by 2 to account for half a square
This is right or no?????
 

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Looks fine. Seems like you picked a lower tuning than I typically have seen for kicker subs, which is fine. Response should be less peaky.

A triangle is half a square, regardless of angle. Area of triangle = 1/2 * height * width, Area of a square = Height * width. To get volume just multiply by depth.
 

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Discussion Starter · #5 ·
Looks fine. Seems like you picked a lower tuning than I typically have seen for kicker subs, which is fine. Response should be less peaky.

A triangle is half a square, regardless of angle. Area of triangle = 1/2 * height * width, Area of a square = Height * width. To get volume just multiply by depth.
Thanks for taking a look, at my page. Do you mind breaking this down more simple in the shape of a square like 2 inch sqaure or whatever size, I never understand formulas to easy can you provide a example, please, if you don't mind.
 

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also, as you can see, a high pass or subsonic filter around 20-25 hz is necessary.
Not necessarily.
When you have done the EQ it might be possible you don't need any Subsonic filter anymore, depending on the music you're listening to.

f.e. my JL 10w3v3 in a ported box cone excursion after tuning in simulation with 400Watts of power going to the sub.

before:
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and after tuning:
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and yes, it's still plenty loud.
 

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Here you go...

Rectangle Slope Plot Font Line


and OP is saying nothing about if a DSP is available or not, but if he has, chances are good, that he doesn't need a subsonic filter.
If he doesn't has one and listen to bass heavy music with bass in the 20Hz range, then yes, definitely, but then he's not after SQ in any way i guess (otherwise he would have a DSP, right?). And according to his own screenshots he still might be within the mechanical limits of his subwoofer, although he's out of linear excursion below 24-25Hz.
 

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Here you go...

View attachment 329449

and OP is saying nothing about if a DSP is available or not, but if he has, chances are good, that he doesn't need a subsonic filter.
If he doesn't has one and listen to bass heavy music with bass in the 20Hz range, then yes, definitely, but then he's not after SQ in any way i guess (otherwise he would have a DSP, right?). And according to his own screenshots he still might be within the mechanical limits of his subwoofer, although he's out of linear excursion below 24-25Hz.
Buddy, he bought a kicker L7 and designed a ported enclosure for it.. What do you think the system goal is? Chill out on the SQ snobbery. The guy is likely a bit a bass head and just wanted to design a decent enclosure for his sub.
 

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I know people who built 2x15" systems for SQ (as those subs then barely move and have a lot less distortion this way).
Having a big sub (no matter the enclosure) doesn't mean he's just going for SPL.
I just said dependant on the music he's listening to and the tuning with a (possibly) available DSP he can get away without a subsonic filter, especially as he's probably not exceeding XMech on his driver.
 

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Discussion Starter · #12 ·
Not necessarily.
When you have done the EQ it might be possible you don't need any Subsonic filter anymore, depending on the music you're listening to.

Thanks for commenting, those parametric EQ bands on your screenshot of Winisd are those simulating a DSP or are they part of a 13 band head unit? Also I'm assuming a DSP is meant for (SQ , OR) to bring more details into the mix like really fine tune the sounds, looking into getting one in the future but have to do more research on it only read a little tiny bit about it.
 

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I have a DSP amplifier, a Mosconi Pico 8/10 DSP.
I have 15 bands of parametric EQ, but anyway. It was just an example that you don't necessarily need a subsonic filter after you applied lowpass filters and parametric EQ (and only the low bands of parametric EQ are relevant in this case, i.e. the bands in the 20-40Hz range).
If you don't have a parametric EQ for your sub, then yes, a mild subsonic filter can prevent overexcursion in your case. Mild filter, because you're not that far beyond Xmax of your driver and Xmax usually is linear maximum excursion. XMech would be maximum mechanical excursion and is usually larger than Xmax of a driver.
But, if you have to lower the volume of the sub by for example by 6 db you can input a static gain filter in the simulation with -6dB to simulate that and then check, if you're still going over the Xmax of your driver, even with the negative gain.
Or if you are setting the amp gain to the minimum you could measure the voltage of the amp at max output and do the math and input the resulting wattage into the WinISD simulation and also check, if you're going over the Xmax of the driver.

Anyway... if you check all this and see that you're not going over Xmax, then there's no need for a subsonic filter imho.
 

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Discussion Starter · #15 ·
Port velocity needs to be under 1 (Mach) (at tuning and above)

Something is wrong, I think when you took that screen shot you had a itty bitty port entered

Because the port size you show wouldn’t do that
What do you mean under 1 Mach is that like a conversion or something, as far as my research my went, I saw that the standard port velocity should be under 17 m/s and 23 m/s is like pushing it. If I remember correctly.
 

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Discussion Starter · #16 ·
I have a DSP amplifier, a Mosconi Pico 8/10 DSP.
I have 15 bands of parametric EQ, but anyway. It was just an example that you don't necessarily need a subsonic filter after you applied lowpass filters and parametric EQ (and only the low bands of parametric EQ are relevant in this case, i.e. the bands in the 20-40Hz range).
If you don't have a parametric EQ for your sub, then yes, a mild subsonic filter can prevent overexcursion in your case. Mild filter, because you're not that far beyond Xmax of your driver and Xmax usually is linear maximum excursion. XMech would be maximum mechanical excursion and is usually larger than Xmax of a driver.
But, if you have to lower the volume of the sub by for example by 6 db you can input a static gain filter in the simulation with -6dB to simulate that and then check, if you're still going over the Xmax of your driver, even with the negative gain.
Or if you are setting the amp gain to the minimum you could measure the voltage of the amp at max output and do the math and input the resulting wattage into the WinISD simulation and also check, if you're going over the Xmax of the driver.

Anyway... if you check all this and see that you're not going over Xmax, then there's no need for a subsonic filter imho.
Very Interesting, doing the math to see the limits, might have to try it out one day, to see it it in action on Winisd, but you need a DSP to simulate it right? but in my case a subsonic filter will work. With a DSP you have more control over the way the bass sounds by tuning the bands? I like the sound of this
 

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Yes, with a DSP you have a lot more control over the response of a driver (doesn't have to be only the sub).
With a DSP you can set crossovers exactly as needed and tailored to your drivers, you can EQ each individual driver, you can time align the drivers so that the soundwaves arrive just in time from every single driver, you can set the gain of each individual driver so they all fit your desired sound.
It just gives you a lot of options you don't have when not having a DSP (obviously).
 

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Very Interesting, doing the math to see the limits, might have to try it out one day, to see it it in action on Winisd, but you need a DSP to simulate it right? but in my case a subsonic filter will work. With a DSP you have more control over the way the bass sounds by tuning the bands? I like the sound of this
Just take note that every filter (highpass and lowpass) also alters the velocity of air in the port (as does all EQ you might do to the sub). So without any filtering you might exceed the port velocity a bit, but after setting high- and lowpass filter it might fit within the guidelines.
You can also simulate this with WinISD. Just enter your desired high- and lowpass filters in the filters section and compare port velocity with and without filters.
 

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What do you mean under 1 Mach is that like a conversion or something, as far as my research my went, I saw that the standard port velocity should be under 17 m/s and 23 m/s is like pushing it. If I remember correctly.
Port velocity is in Mach… ya know speed of sound , at least it is in termlab

So , idk about isd , but that port velocity shouldn’t show ms , it should show speed

And , the GD would be in ms

If I’m not mistaken
 

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Port velocity is in Mach… ya know speed of sound , at least it is in termlab

So , idk about isd , but that port velocity shouldn’t show ms , it should show speed

And , the GD would be in ms

If I’m not mistaken
In WinISD it is "meters per second", abbreviates as m/s, not ms. ;)
 
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