I'm building a subwoofer for the trunk of my Subaru Crosstrek.
I have 42.5in x 26in and would prefer the height be 2-4in. I'm having trouble with tuning of the box, as if the port is too wide the speakers go into over excursion, if they are thinner they easily go over 18m/s. I'm not sure how to model tapered waveguides or adding a flare in terms of port length. I'm a mech e but new to audio design, so joined here to learn as much as I could about complex analysis and subwoofer optimization.
I've tried sealed box, ported, 4th order (to basically act as a spring to reduce excursion, but I'm limited on tuning frequency because the back volume can't get any bigger without overexcursion), 6th order series and parallel, have played with 12in low profile sub, but don't know how to simulate downfiring and top must be encloseed as it will be the new trunk surface. The 12in is also pretty tall.
I'd be using an LX1300.1 with about 550W at a 2ohm load. Design shown is 6 Dayton Audio 2x7s. I'm trying to get low. I will have 2x 10in self powered el cheapos behind the driver and passenger seats, which will cover the 60-100hz range fine. That's what I did in the truck and it did the trick. I've never had low low bass and don't want to miss out on this opportunity with a brand new car.
I've attached a few pictures, but I've been through very many iterations, these are just some recent ones to show the process of building the subwoofer.
I'm also not opposed to passive radiators, but the only 2in or less ones are cheapo knockoffs with no TS parameters for excursion or moving mass or anything so I don't know how to begin that calculation.
I have 42.5in x 26in and would prefer the height be 2-4in. I'm having trouble with tuning of the box, as if the port is too wide the speakers go into over excursion, if they are thinner they easily go over 18m/s. I'm not sure how to model tapered waveguides or adding a flare in terms of port length. I'm a mech e but new to audio design, so joined here to learn as much as I could about complex analysis and subwoofer optimization.
I've tried sealed box, ported, 4th order (to basically act as a spring to reduce excursion, but I'm limited on tuning frequency because the back volume can't get any bigger without overexcursion), 6th order series and parallel, have played with 12in low profile sub, but don't know how to simulate downfiring and top must be encloseed as it will be the new trunk surface. The 12in is also pretty tall.
I'd be using an LX1300.1 with about 550W at a 2ohm load. Design shown is 6 Dayton Audio 2x7s. I'm trying to get low. I will have 2x 10in self powered el cheapos behind the driver and passenger seats, which will cover the 60-100hz range fine. That's what I did in the truck and it did the trick. I've never had low low bass and don't want to miss out on this opportunity with a brand new car.
I've attached a few pictures, but I've been through very many iterations, these are just some recent ones to show the process of building the subwoofer.
I'm also not opposed to passive radiators, but the only 2in or less ones are cheapo knockoffs with no TS parameters for excursion or moving mass or anything so I don't know how to begin that calculation.
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Gotta move air to make bass. Those little drivers will probably not be up to it.
How about a sealed or vented subwoofer built into the spare tire well? That way you get to keep your trunk. It's the solution I used for my vehicle.
How about a sealed or vented subwoofer built into the spare tire well? That way you get to keep your trunk. It's the solution I used for my vehicle.
You're absolutely right. The xmax is too low and the SD is only around a 10in even with 6 of these. So a single 10 would be better technically. I wonder if I could chuck in like 2 8s in a downfire. Even then it gets too thick, and I feel would only hammer the 50-100 range too hard while leaving the 20-50 range in the dust. Don't know why I figured proper porting could change physics, obviously I need to move a huge amount of air in one gust.
The spare tire well is small, and I'd like to retain the spare so my wife never gets stranded somewhere.
I'm looking into downfiring low profile drivers. I saw the peerless gbs and they looked awesome, as well as some low profile tang band drivers. Obviously all of the high excursion drivers are sold out. The kicker l7t subs are nice, but mounting depth is so deep. I'd rather do 8 of the 8" peerless than 1 12in because I have plenty of area, just a small amount of height to hit target.
Stuns me these manufacturers don't get supply and demand.
The spare tire well is small, and I'd like to retain the spare so my wife never gets stranded somewhere.
I'm looking into downfiring low profile drivers. I saw the peerless gbs and they looked awesome, as well as some low profile tang band drivers. Obviously all of the high excursion drivers are sold out. The kicker l7t subs are nice, but mounting depth is so deep. I'd rather do 8 of the 8" peerless than 1 12in because I have plenty of area, just a small amount of height to hit target.
Stuns me these manufacturers don't get supply and demand.
Ya I'm noticing those little drivers just dont push enough air, realistically I'd need an army of them. Limits me to shallow mounts. The best I've seen are the peerless gbs if only I could buy 8 of them and slap it in downfire mode. Going to test and see if that would be any good with the volume I have when I'm off work.
Also, that is a wicked crown vic setup, the power on that thing geez!
Also, that is a wicked crown vic setup, the power on that thing geez!
Here is the best design I have so far to fit my car. 8 drivers set to push 280w (max driver capacity). Though, I have a notch in the box to avoid a lip. I don't know if that volume counts towards the drivers or if it acts as an extension of the port.
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Also, since it is a ported design, am I able to use .25 acrylic on top/bottom or does it need to be thicker?
Any reason you cant have the sub enclosure on one side of your trunk/boot moulded into the space around the wheel tub so you still retain as much space as possible, raising the floor height usually make the space less practical.
White line is with low and high pass filter. I've been looking at 2 peerless gbs 8in in a downfiring position with 2 ports going to the back sides of the trunk where there is a little space against the sidewall not to restrict the ports. Has a pretty gradual rolloff from 50hz down so should still be able to get some low end response with less complexity of the build.
Spare tire space gives some more volume for sure, but then I lose the spare tire. This box design allows me to lift it then get to the tire. At 3.5in I can still fit my suitcase and just maybe even the cooler. I mocked it up with some 2x4s (1.5x3.5in") and cardboard.
With those 2 in series and 2 8in in parallel enclosed boxes behind the front seats between the fabric and the front seat, I should be able to push 600 watts in and have ok low end and a pretty strong midbass, with tactile feel into the driver seat. Which I like, that's what I did in my truck.
Spare tire space gives some more volume for sure, but then I lose the spare tire. This box design allows me to lift it then get to the tire. At 3.5in I can still fit my suitcase and just maybe even the cooler. I mocked it up with some 2x4s (1.5x3.5in") and cardboard.
With those 2 in series and 2 8in in parallel enclosed boxes behind the front seats between the fabric and the front seat, I should be able to push 600 watts in and have ok low end and a pretty strong midbass, with tactile feel into the driver seat. Which I like, that's what I did in my truck.
I'll send pics of that once I get the design more put together and mocked up with the better 3D scan. I would LOVE an acrylic top, however I would also love it to be 0.25in thick, so need to come up with bracing that would allow me to see into the box and still use it as a top.
This is my current best basic box design. You can see where it fits in the car. There is a 0.75" gap for the rear wave to go into the car, and the front wave goes into the enclosed box.
I've modeled 2 different enclosures. A "6th Order" just because it is downfiring so I modeled it basically like a port. The other is a super tiny enclosure for behind the front and passenger seat, off the same amp channel in parallel. I'm not quite sure how to sum the functions of both of these subs together, but think it should be ok for the daily driver.
4in tall, 42in wide at the widest, 26in deep.
I have some bracing, they are uneven on purpose for the resonance. I may or may not need to add more, 0.5in MDF with circles cut through.
2x2.5in ports going both directions into a cupholder section, so it isn't blocking the ports.
The top is set as 0.75 MDF, I'd like to be able to see through, but am thinking that isn't possible. Especially for my first box to add problems with the sound, maybe I router in and add some LEDs with a diffusion material to make some pretty lettering instead of see through.
What do y'all think? 4 subs total, 2 in the trunk, 1 behind each seat, 2 in series and 2 in parallel for around 1.8ohm being able to get close to the max output for the 4 drivers (GBS-200F35CP02-04) with the sub channel of an LX1300.7 amplifier.
I've modeled 2 different enclosures. A "6th Order" just because it is downfiring so I modeled it basically like a port. The other is a super tiny enclosure for behind the front and passenger seat, off the same amp channel in parallel. I'm not quite sure how to sum the functions of both of these subs together, but think it should be ok for the daily driver.
4in tall, 42in wide at the widest, 26in deep.
I have some bracing, they are uneven on purpose for the resonance. I may or may not need to add more, 0.5in MDF with circles cut through.
2x2.5in ports going both directions into a cupholder section, so it isn't blocking the ports.
The top is set as 0.75 MDF, I'd like to be able to see through, but am thinking that isn't possible. Especially for my first box to add problems with the sound, maybe I router in and add some LEDs with a diffusion material to make some pretty lettering instead of see through.
What do y'all think? 4 subs total, 2 in the trunk, 1 behind each seat, 2 in series and 2 in parallel for around 1.8ohm being able to get close to the max output for the 4 drivers (GBS-200F35CP02-04) with the sub channel of an LX1300.7 amplifier.
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I noticed my model didn't have the overlap underneath the riser, 0.75in overlap for base board and baffle. Here is the downfiring location and opening. Also added 45s to the port.
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A couple of these (https://www.crutchfield.com/S-fmNFyKPOiHf/p_13610TW3/JL-Audio-10TW3-D4.html) and seal that enclosure up, and it will perform very well in a car.
Speakers with a Fs of 50 to 60 Hz dont go " low"
Plus the efficiency is low.
To much emphasis on " power" equals anything useful.
2x 6x9 on the rear deck would make more bass
Use a 1x12 minimum more like 2x12
pretty standard stuff.
2 to 4 inches is not a box of any workable nature.
What do people actually put in their trunk?
Subs go to the sides or up under the rear deck for trunk space.
Use low profile subs if needed, and correct volume
Plus the efficiency is low.
To much emphasis on " power" equals anything useful.
2x 6x9 on the rear deck would make more bass
Use a 1x12 minimum more like 2x12
pretty standard stuff.
2 to 4 inches is not a box of any workable nature.
What do people actually put in their trunk?
Subs go to the sides or up under the rear deck for trunk space.
Use low profile subs if needed, and correct volume
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