Can you just eye ball 4th orders?

Higher - if you model it, ported enclosures tend to peak at a frequency slightly above tuning.

That is dependant on vehicle and that vehicles cabin gain. Without cabin gain a ported box would peak at tuning.

If you are tuned low and in a larger vehicle it is likely that you peak higher than tuning because cabin gain couples with the box peak makes it that way.

In a small vehicle you could be tuned to 36hz and peak down in the low 30s.

My truck peaks lower than box tuning by a bit this helps me extend my subs frequency response to be flatter for a wider range by tuning the box higher and using the cabin gain down lower.

If I tuned to my cabin gains peak it would couple with the box tuning and I could gain db quite easily. But it would be a very peaky response curve
 
Where a vehicle peaks is also based on like sheet metal resonance, structural quality, noise insulation and strength of the vehicle body as it’s flexing. I’ve noticed vehicles like German cars can peak lower or hold lows better, like a VW Jetta, where something like a 90’s Honda Civic can peak higher.

With Ford Explorers, which I have a long history with, the 2nd gen ones peaked in the high 40’s or low 50’s iirc, and my 3rd gen peaked at 35-36 hz hard (so did the 4th gens) with a secondary peak around 70 hz. Those Explorer generations are fairly similar in size and yet peak like 10-20 hz apart with non-walls.

I think it’s the same type peak changes between similarly sized vehicles, where you can have one fully deadened vehicle and another that’s not, and the fully deadened vehicle of the exact same type is going to peak lower due to the added mass to all the panels. Just like adding Mms to a sub will make its Fs lower. There’s a lot of factors to sound, lol.
 
Last edited:
Higher - if you model it, ported enclosures tend to peak at a frequency slightly above tuning.

I agree with this as a general statement- ported boxes tend to peak higher in vehicles than their tuning. I have designed for people where they peak lower than tuning with ported boxes, but iirc that’s usually a more extreme system situation with a bunch of changes to the vehicle itself, and it’s fairly rare, from everything I’ve seen/heard. Most people tune low enough where cabin peak is above tuning, so very rarely have I seen ported peak below tuning, but it does happen. I’ve had someone tuned at 29-30 hz peak 1-2 hz below that tuning.
 
Last edited:

Where you put the box (more specifically port) inside of a vehicle can help change peaks. If you take a big vehicle like a suburban or any open cab vehicle from front to back, the length from front to back is like a t-line, where you can place the port inside of the vehicle cab like you’d place the sub in a certain position in the t-line to aim at boosting that 1/4 wave distance. Flat walls can take advantage of this, for example, where you can put the face of the wall a certain distance from the front of the vehicle based on 1/4 wave tuning, so that the space in between the wall face and the front of the cabin acts as a 1/4 wave resonator for whatever wavelength you wind up with for the distance between. You can really apply that to anything, because that’s just how sound works. It’s like using your cabin as another somewhat tuned enclosure.
 
Where you put the box (more specifically port) inside of a vehicle can help change peaks. If you take a big vehicle like a suburban or any open cab vehicle from front to back, the length from front to back is like a t-line, where you can place the port inside of the vehicle cab like you’d place the sub in a certain position in the t-line to aim at boosting that 1/4 wave distance. Flat walls can take advantage of this, for example, where you can put the face of the wall a certain distance from the front of the vehicle based on 1/4 wave tuning, so that the space in between the wall face and the front of the cabin acts as a 1/4 wave resonator for whatever wavelength you wind up with for the distance between. You can really apply that to anything, because that’s just how sound works. It’s like using your cabin as another somewhat tuned enclosure.

Yea I mentioned something similar about big changes in vehicle volumes, deadening, earlier.

I don't go so far as trying to tune my truck but I know if I have a peak 28-32hz tuning the box around 36hz typically extends my flat response curve further that what the typical box program will show. That's how I ended up with 2 6.5s in a box tuned to 36hz playing 30hz with such authority. At the time I didn't know my cabin gain I used to have the measured gain line saved on my phone from when I had my 2 sa10v2s under the seat. But that phone broke and I lost alot of info off it. Getting ready to retest everything again here shortly. I need to order a mic for the rta and drag a spare sub out of storage.

I'd love to get this tc3 motor built up. I need to find a local builder
 
That is dependant on vehicle and that vehicles cabin gain. Without cabin gain a ported box would peak at tuning.

If you are tuned low and in a larger vehicle it is likely that you peak higher than tuning because cabin gain couples with the box peak makes it that way.

In a small vehicle you could be tuned to 36hz and peak down in the low 30s.

My truck peaks lower than box tuning by a bit this helps me extend my subs frequency response to be flatter for a wider range by tuning the box higher and using the cabin gain down lower.

If I tuned to my cabin gains peak it would couple with the box tuning and I could gain db quite easily. But it would be a very peaky response curve

I was saying the free air peak of the enclosure will be high than tuning. Once it's in a car cabin gain has big effect.
 
My box is tuned to 31-32hz and it peaks at 40hz inside the car. The car flexes way too much below 40 hz which is something I feel that takes away from the output. In need a truck and I’m working on that now 😂.
 
And where do you put the meter? Are the doors open or closed? Are the windows up or down? Do I do a full competition burp or a sweep? What if the wind is blowing 50 m.p.h.? I'm guessing that I need 10 foot speaker wires to do this. You guys make it sound so easy when there is a lot of variables.

Point of reference for this sort of thing is meant to be 1 meter away from the sound source in an an-echoic chamber. You probably don't have access to that and you can't do anything about reflection off of the ground but you could be most of the way there on a quiet day in the desert. Doing RTA or sweep would likely be very informative to compare response to predicted (should be much closer to the WinISD graph outside).

There should not be any frequency below 100hz where this will be louder outside the vehicle.
 
Activity
No one is currently typing a reply...

Similar threads

So I don't know what i'm doing but I really like the used H-KO but when i look at the specs it looks like it could overpower the sub if I'm...
19
1K
you may like them facing forward rather than Rear faced. Its all about how you like and enjoy by your ear/listening not others. try Both...
8
716
is this a ported enclosure or a 4th order? If 4th and tuned to 33hz, unless specifically designed to do that, it wont have any bandwidth. It might...
4
1K
I’m going to stick with the 4th order bandpass for now and see if it can improve it. The bandpass actually plays 100 rebased songs good.
3
1K

About this thread

Jake321

CarAudio.com Recruit
Thread starter
Jake321
Joined
Location
Hawaii
Start date
Participants
Who Replied
Replies
37
Views
3,689
Last reply date
Last reply from
hispls
1000006564.jpg

Mr FaceCaser

    Mar 28, 2024
  • 0
  • 0
1000006569.jpg

Mr FaceCaser

    Mar 28, 2024
  • 0
  • 0

Latest topics

Top