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I hate sealed boxes. Never heard, or built one I liked..... Or used for more than a week.
But anyway, just curious, what kind of vehicle do you have, that you can't find room for a couple 8"s or a single 10" ported ? Both would be relatively small enclosures.
I have a single 8" in the back of my Prius, in a ported enclosure, and I think it was only .6 cubes net ? You could do away with the port volume too, if you used a passive radiator.

PS, if you want more, nicer sounding bass, and truly can't make enough cubes of space for the sub(s), can you cut a hole somewhere ? True Infinite Baffle setups use next to no cabin space, and can make BIG bass, on minimal power ☺

I'm running a huge 5 cu ft net enclosure for my 18" sub right now, and it sounds great ! But my next setup will be true IB setup, with a 24" Stereo Integrity sub. It will take far less space than my 18" sub does now.
 

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Discussion Starter #42
I hate sealed boxes. Never heard, or built one I liked..... Or used for more than a week.
But anyway, just curious, what kind of vehicle do you have, that you can't find room for a couple 8"s or a single 10" ported ? Both would be relatively small enclosures.
I have a single 8" in the back of my Prius, in a ported enclosure, and I think it was only .6 cubes net ? You could do away with the port volume too, if you used a passive radiator.
Jaguar F-type coupe. It's got just enough room in the trunk for a weekend trip but does have a storage compartment under the floor that I'm willing to sacrifice. I haven't actually determined how much space I can manage out of it but pretty sure it will be 1cuft max and likely more in the .6-.8 range.

I've only ever had sealed enclosures (except for a big compound box with 15" back in college) and I'm happy with that in general. My other car currently has a 10" IDQV3 sealed getting 400W and that's sufficient. I have JBL GTO804 that I just built a little .3 shoebox for as a tester. Still need to install my amp so can't try it out yet but that will give me a starting point for reference. I at least have room for a single 10" though.
 

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Jaguar F-type coupe. It's got just enough room in the trunk for a weekend trip but does have a storage compartment under the floor that I'm willing to sacrifice. I haven't actually determined how much space I can manage out of it but pretty sure it will be 1cuft max and likely more in the .6-.8 range.

I've only ever had sealed enclosures (except for a big compound box with 15" back in college) and I'm happy with that in general. My other car currently has a 10" IDQV3 sealed getting 400W and that's sufficient. I have JBL GTO804 that I just built a little .3 shoebox for as a tester. Still need to install my amp so can't try it out yet but that will give me a starting point for reference. I at least have room for a single 10" though.
Bro, that is a sweet car ! 👍
,Anyway I bet you could find a 10" sub that would work "well" (not the minimum) of .8 cubes.... Then run it with a 12" passive radiator to save space, Bam ☺
 

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2 drivers in a half of space for one woofer and you get output as you would get with one woofer. It will dig low but with -3dB output
 

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That's I was I thinking. I know PR are popular in home audio towers that may have 4 x 6" cones with 2 of the 4 acting as PRs in addition to the mids, tweets, etc.. but at what point is it better to use a PR in a car audio application?

Again.. I'm just trying to learn a little more about PRs in general.
  • If one has a small volume of space then a PR should at least be considered.
  • The port volume needs to be removed from the box volume
  • If the port tuning freq is very low, then a PR does that more easily than say a 4 foot long port
  • If there is port chuffing, then a larger diameter port can ameliorate that, but then the port and the volume/space increase together... So a PR offers the advantage of minimizing the box volume as a PR is a "volumeless port".
  • In a home theatre setup it might make more sense to have a PR as there is typically some very low tuning frequencies 10-20 Hz
.- A PR it is tunable, so one needs a wrench or screw driver to change it post-facto, this allows for some errors in port tuning to be corrected afterwards by adding or removing the weights..
- In a car the problem may be that a PR needs to be tuned higher than it is capable of (usually they tune around 25 Hz or less... Sometimes a bit higher than 25, but usually <30Hz.

Those are most of the basics.
Since the volume of the box was a significant issue for thi install, it seemed worth mentioning them.
It provides the minimum volume 4th order (vented box), at the cost of $ for the PR.
 

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What r u saying will cut the box size in half + lose 3 db's ?
yeah... so if the ox size is more important than the 3dB, then one should at least be aware of Isobaric as a way to do that trade study and whether they are will to trade sound volume for spatial volume...
 

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yeah... so if the ox size is more important than the 3dB, then one should at least be aware of Isobaric as a way to do that trade study and whether they are will to trade sound volume for spatial volume...
Yes. I totally studied, and even experimented with isobaric enclosures last year.
I just missed "isobaric" being mentioned when I speed read this thread. Carry on.
 

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  • If one has a small volume of space then a PR should at least be considered.
  • The port volume needs to be removed from the box volume
  • If the port tuning freq is very low, then a PR does that more easily than say a 4 foot long port
  • If there is port chuffing, then a larger diameter port can ameliorate that, but then the port and the volume/space increase together... So a PR offers the advantage of minimizing the box volume as a PR is a "volumeless port".
  • In a home theatre setup it might make more sense to have a PR as there is typically some very low tuning frequencies 10-20 Hz
.- A PR it is tunable, so one needs a wrench or screw driver to change it post-facto, this allows for some errors in port tuning to be corrected afterwards by adding or removing the weights..
- In a car the problem may be that a PR needs to be tuned higher than it is capable of (usually they tune around 25 Hz or less... Sometimes a bit higher than 25, but usually <30Hz.

Those are most of the basics.
Since the volume of the box was a significant issue for thi install, it seemed worth mentioning them.
It provides the minimum volume 4th order (vented box), at the cost of $ for the PR.
I agree on all of this except...
I thought tuning up or down from any frequency the enclosure was built for would be just as easy, no ? I mean, couldn't you build a box turned at 60 Hz, with a PR, then raise it or lower it from say 55-65hz, just as easily. As box built for 30 Hz, and raising or lower it from say 25-35 ?
 

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I agree on all of this except...
I thought tuning up or down from any frequency the enclosure was built for would be just as easy, no ? I mean, couldn't you build a box turned at 60 Hz, with a PR, then raise it or lower it from say 55-65hz, just as easily. As box built for 30 Hz, and raising or lower it from say 25-35 ?
For a given tuning frequency, as box volume increases, the port length generally decreases.

Also as the box's tuning freq gets further away from the port freq, I "think" maybe the group delay gets worse?
It also may need more DSP for peakiness.

It may be non-optimal with a small box that is too small for the low tuned port freq, but at least it fits the space available.
 

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Came here to look for a sub for an F-Type convertible. I've seen the under seat prefabs recommended but I'm wanting more. I'll grab some popcorn

cheers
 

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Discussion Starter #56
Came here to look for a sub for an F-Type convertible. I've seen the under seat prefabs recommended but I'm wanting more. I'll grab some popcorn
I'm not familiar with the specifics of the convertible trunk aside from knowing it's small. Do you have the additional storage tub compartment under the floor where the battery and relays are? I haven't done measurements yet but it should accommodate a decent sealed 10". A bit of fiberglass work would maximize the available space but not sure if it's necessary.
 

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no to the storage. The convertible has a steel bulkhead behind the seats with the top stored behind that. Due to that, the trunk is a no go for me. Under seat and footwell appear to be the only common sub placement areas between the 2 models.
 

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Discussion Starter #58
Your best bet is a slim enclosure behind the seat(s) or put in the work to make the stock sub location an appropriate enclosure.
 
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