Hi everybody,
I hope that is not too much if I ask you for a brief calculation of a ported box for a Bass-face SPL15.2 driver. The recommendation box from manufacturer is a 3.5 Cubic Feet (that's easy to calculate) tuned at 35HZ (Well that's not so easy to calculate for me).
For the moment i use it in a box which is W 550 X H 414 X D 450 mm (exterior dimensions) built from 18mm MDF and the bass-reflex is a slot of 50 X 378 mm and 432 mm deep(on the right side of the box) , but the sound is not the one i would expect from such a driver.
I would prefer to build it in the same way,with a slot bass-reflex on the right side of the box.
These are the T/S parameters:
TS Parameters BL T m: 26.078
TS Parameters Cms uM N: 20.376
TS Parameters EBP: 93.769696
TS Parameters Fo Hz: 46.416
TS Parameters Levc uH: 598.185
TS Parameters Md g: 300
TS Parameters MMd g: 563.283
TS Parameters Mms g: 577.022
TS Parameters No %: 0.389
TS Parameters Qes: 0.495
TS Parameters Qms: 3.561
TS Parameters Qts: 0.435
TS Parameters Revc Ohm: 2
TS Parameters Sd Cm sq: 829.58
TS Parameters SPL Db: 87.9
TS Parameters Vas Ltr: 199.12
TS Parameters Xmax mm: 36.33
Single Speaker Max Power: 4000
Single Speaker RMS Power: 2000
Speaker Overall Diameter mm: 400
Speaker Magnet Diameter Including Magnet Protector mm: 200
Speaker Installation Cutout Diameter mm: 360
Speaker Overall Depth mm: 220
Speaker Mounting Depth mm: 190
Speaker Front Protrusion From Mounting Plane mm: 30
Speaker Impedance Nominal Ohm: 4+4
Speaker Sensitivity db 1Wm: 86
Recommended Cable: PSC12.1
Voice Coil Diameter mm: 75
Thank you very much!
I hope that is not too much if I ask you for a brief calculation of a ported box for a Bass-face SPL15.2 driver. The recommendation box from manufacturer is a 3.5 Cubic Feet (that's easy to calculate) tuned at 35HZ (Well that's not so easy to calculate for me).
For the moment i use it in a box which is W 550 X H 414 X D 450 mm (exterior dimensions) built from 18mm MDF and the bass-reflex is a slot of 50 X 378 mm and 432 mm deep(on the right side of the box) , but the sound is not the one i would expect from such a driver.
I would prefer to build it in the same way,with a slot bass-reflex on the right side of the box.
These are the T/S parameters:
TS Parameters BL T m: 26.078
TS Parameters Cms uM N: 20.376
TS Parameters EBP: 93.769696
TS Parameters Fo Hz: 46.416
TS Parameters Levc uH: 598.185
TS Parameters Md g: 300
TS Parameters MMd g: 563.283
TS Parameters Mms g: 577.022
TS Parameters No %: 0.389
TS Parameters Qes: 0.495
TS Parameters Qms: 3.561
TS Parameters Qts: 0.435
TS Parameters Revc Ohm: 2
TS Parameters Sd Cm sq: 829.58
TS Parameters SPL Db: 87.9
TS Parameters Vas Ltr: 199.12
TS Parameters Xmax mm: 36.33
Single Speaker Max Power: 4000
Single Speaker RMS Power: 2000
Speaker Overall Diameter mm: 400
Speaker Magnet Diameter Including Magnet Protector mm: 200
Speaker Installation Cutout Diameter mm: 360
Speaker Overall Depth mm: 220
Speaker Mounting Depth mm: 190
Speaker Front Protrusion From Mounting Plane mm: 30
Speaker Impedance Nominal Ohm: 4+4
Speaker Sensitivity db 1Wm: 86
Recommended Cable: PSC12.1
Voice Coil Diameter mm: 75
Thank you very much!
Last edited:
Thank for reply.
How can i help the sound in the current box in the quality side?
If it's not too much can you please give me some details about a quality-oriented box?
Thanks!
The bass is not loud,not deep and not clean in the same time( is somehow a little bit distorted).
Forgot to mention that i am using a ground zero GZTA2.500TX 500W amplifier, but a GZNA 2800X which has 3 times the power of the actual one is on the way, so maybe under-powered speaker can be a reason...
Forgot to mention that i am using a ground zero GZTA2.500TX 500W amplifier, but a GZNA 2800X which has 3 times the power of the actual one is on the way, so maybe under-powered speaker can be a reason...
I just modeled it and it looks like 100ltr tuned to 35hz is fine, but I would just cover the port and make the box airtight. You'll sacrifice a bit of extension for a much tighter and cleaner low frequency response. As long as you get the crossover right, and give it enough power, it should sound great.
I've been modeling loads of subwoofers lately and yours in a 75ltr to 100ltr sealed box looks pretty good to me. Obviously i've had to guess cabin gain but without measuring your vehicle, guessing is all you can do.
I've been modeling loads of subwoofers lately and yours in a 75ltr to 100ltr sealed box looks pretty good to me. Obviously i've had to guess cabin gain but without measuring your vehicle, guessing is all you can do.
Can you please tell me how much i should cover the port? Or can i make it shorter maybe? Can you also send me the simulation file, so i can see the way you did it? (and learn something )
What frequency do you think i should have the crossover? Here is a very strange thing ... i have a subwoofer output from the head-unit which already has a crossover, but with fixed cutouts of 80 , 100 and 120 Hz . I find that 80Hz is not low enough, so i need to enable LPF on the amplifier also, and bring the cutting frequency down. I read somewhere that i should not use 2 crossovers in the same time (in series) ... Maybe i should connect the amp to a normal output (on the head-unit side) also?
About the power, i use for the moment a 500W rms GZ amp, but a 1500W one is on its way. That should help a lot i think, because the gain on this one is set to ~ (or more than) 85% .
About the cabin gain, i have a Citroen C4 Grand Picasso, so it's a mono(big)volume car, and the subwoofer is in the trunk facing up ( i tried to place it like normal, facing rear, but makes no difference... in fact, sounds a little bit better facing up ).
Completely cover the port and make sure the whole box is airtight. You don't want air leaking from anywhere. I've used smoke bombs to test for leaks in the past. They stink but work well. Also make sure the cabinet is well braced.
The crossover looks like it could be the difficult bit. I've only just started getting into car hifi, so don't have much practical experience, only simulations. According to my sims, If you set an active crossover to a certain frequency (say 80hz) it will react differently depending on the actual frequency response of the subwoofer used. One subwoofer may give you a 4th order roll-off another may give you a second order roll-off (the same is true with passive speakers). Playing around with the one in your head unit and amp will help i'd imagine. I've got an Dayton Omnimic v2 for measuring the frequency response, so this is what i'm planning to use when I fit my sub.
When setting up the crossover frequency and gain it's important to get the phase as near as possible. If you dont have a phase switch on your amp, just try reversing the polarity of the speaker wires going into the subwoofer. The correct phase should sound louder at the crossover frequency (unless it's a third order acoustic, but don't worry about that for now)
If I can't get my sub to play nicely with my mains, i'm going to use a combination of passive and active but you need speaker design knowledge and measuring gear for that. Even then, it's not a walk in the park.
The crossover looks like it could be the difficult bit. I've only just started getting into car hifi, so don't have much practical experience, only simulations. According to my sims, If you set an active crossover to a certain frequency (say 80hz) it will react differently depending on the actual frequency response of the subwoofer used. One subwoofer may give you a 4th order roll-off another may give you a second order roll-off (the same is true with passive speakers). Playing around with the one in your head unit and amp will help i'd imagine. I've got an Dayton Omnimic v2 for measuring the frequency response, so this is what i'm planning to use when I fit my sub.
When setting up the crossover frequency and gain it's important to get the phase as near as possible. If you dont have a phase switch on your amp, just try reversing the polarity of the speaker wires going into the subwoofer. The correct phase should sound louder at the crossover frequency (unless it's a third order acoustic, but don't worry about that for now)
If I can't get my sub to play nicely with my mains, i'm going to use a combination of passive and active but you need speaker design knowledge and measuring gear for that. Even then, it's not a walk in the park.
Jakobsson, can you please send me the project? I now downloaded Winisd and i want to start playing with it, so the project you simulated would help me a lot.
Thanks!
I don't see a 5db peak at 35hz with a 100ltr box tuned to 35hz.
This is what happens to the frequency response, when you put a sealed subwoofer in a car - JBL GTO 804
You get a gain of roughly 25db at 20hz, so you need to think about that when your modeling your subwoofer.
This is what happens to the frequency response, when you put a sealed subwoofer in a car - JBL GTO 804
You get a gain of roughly 25db at 20hz, so you need to think about that when your modeling your subwoofer.
A smaller box gives even less bass at the tuning frequency. I just double checked the t/s parameters and they seem to be right. Not sure why you're getting a peak.
My misstake!, i double checked the driver and it pretty much spot on.
-3db at 40hz
I'm sorry if i have given you headache
Ok, back to integration of sub to front.
I usually test all seperate components before integrating them together.
Make test with tone generator/rap/hip-hop with only sub playing.
What kind of music are you listening to?<- really important
Name one favorite
Have a look at subwoofer diy site lots of guidance and tools you seem to know about t/s parameters so some of the spreadsheets ect, may be very usefull to you. Also deep deep in the vaults of this site you will find loads of helpfull info
Go-on build a new one its great fun and you know it makes sense
Go-on build a new one its great fun and you know it makes sense
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