Box guru's come on in ***Testing completed

[DubNDodge]

did you account for port displacement of your new bigger port

Is that 4.55 cuff net or gross volume? What is the displacement of your port? This along with driver displacement subtracts from total volume of the box. This makes your box a little on the small side and causes port tuning to go up.

4.55 net. I calculated it considering port displacement, bracing displacement, and driver displacement.

Have you checked the tuning of your new box to see what you are getting in the vehicle? You can play test tones and look for the frequency that the sub moves the least.

I'll do that this weekend.

Old box is for a trunk car, new box is not, if you tested each box in different vehicles your results may depend on the vehicles as well, other than that a sketch with dims for the new box would help to recheck it's specs.

It's definitely 4.55 net. That's considering post displacement, bracing displacement, and driver displacement. 16"x 22" x39.5" bracing is .3

One of your subs is unloading directly into the port, that has a bit to do with it. Also, published T/S specs are NEVER EVER accurate. Even with sundown level stuff, there's still a huge variance between one driver and another. Do yourself a favor, buy a WT3, and sweep your own T/S specs.

it isn't "directly" unloading into the port. the mouth of the port is a solid 2.5" away from the edge of the driver. I say "directly" because people have said I should 180 degree the bend in my port vs having it 90 degree behind that sub.

[DubNDodge]

having so much port area, im sure your response takes a nosedive under tuning. Model it up, check port velocity.

yeah paul did that for me, it was supposed to reach down to 24 fairly well.

[DubNDodge]

Went out and finally did some testing. Ran a sweep to see my bandwidth and impedance rise from 60Hz-25Hz.

Results:

I then added a bunch of 2x4s at the mouth of the port where everyone thought it may be unloading into.

Here is the sweep afterwards, not much of a change. Might have gained a Db on the lower end.

Here is a excel graph of the impedance rise for before the mod and after the mod. It seems to have had an effect. Not sure what to grasp from the change in the impedance. Definitely less peaky. (Used an AMM-1 in Freq/AC impedance mode and video recorded the sweep)

[Triticum Agricolam]

That impedance graph looks really weird. Did you get a chance to check your tuning frequency by watching cone movement?

The impedance graph for a ported box should have two peaks in it. One above and one below tuning, the lowest point between the two peaks should be right around where the tuning is.

Probably the only thing adding those 2x4 did was effectively lengthen your port a bit and lower your tuning slightly. I guess it was worth a shot, but I don't think unloading is your issue regardless.

If you can't check your tuning and let us know where you are getting the least cone movement at, that would give us some insight.

[DubNDodge]

Well apparently I had the nets wrong, I forgot about bracing in the old box. Here is the new net of the current box as well.

Here are some more interesting stats.

Old box, with port plug and subs loaded/and the bracing.

Current box, with the port mouth mod.

[DubNDodge]

That impedance graph looks really weird. Did you get a chance to check your tuning frequency by watching cone movement?

The impedance graph for a ported box should have two peaks in it. One above and one below tuning, the lowest point between the two peaks should be right around where the tuning is.

Probably the only thing adding those 2x4 did was effectively lengthen your port a bit and lower your tuning slightly. I guess it was worth a shot, but I don't think unloading is your issue regardless.

If you can't check your tuning and let us know where you are getting the least cone movement at, that would give us some insight.

It is extremely hard to see it. There really isn't a point at which the excursion isn't at full. My old box for these things, the tuning was right at 28hz because they barely moved at all.

[CleanSierra]

Port inefficiency would be my guess. I don't like ports(personally) that make a 180° turn.

You might have sounded louder before due to port velocity being high. It might have aided in loudness a bit because it was constricted.

[DubNDodge]

Port inefficiency would be my guess. I don't like ports(personally) that make a 180° turn.

You might have sounded louder before due to port velocity being high. It might have aided in loudness a bit because it was constricted.

Originally it was going to be a 90 degree turn. I was talked into a 180 by hunter. Yeah, my velocity before was pretty nuts. My passengers hair would be blown around by the port which was ~4 ft away, or whatever it was to the back of of the back seats.

[DubNDodge]

That impedance graph looks really weird. Did you get a chance to check your tuning frequency by watching cone movement?

The impedance graph for a ported box should have two peaks in it. One above and one below tuning, the lowest point between the two peaks should be right around where the tuning is.

Probably the only thing adding those 2x4 did was effectively lengthen your port a bit and lower your tuning slightly. I guess it was worth a shot, but I don't think unloading is your issue regardless.

If you can't check your tuning and let us know where you are getting the least cone movement at, that would give us some insight.

It is extremely hard to see it. There really isn't a point at which the excursion isn't at full. My old box for these things, the tuning was right at 28hz because they barely moved at all.

I went up and played a sweep at least 10 times at 3/4 tilt. The peak to peak was like a half inch, until it hit 32 seconds in my sweep, which was right about 39-38hz. At that point it was a 1.5" peak to peak down the rest of the way.

[CleanSierra]

Port inefficiency would be my guess. I don't like ports(personally) that make a 180° turn.

You might have sounded louder before due to port velocity being high. It might have aided in loudness a bit because it was constricted.

Originally it was going to be a 90 degree turn. I was talked into a 180 by hunter. Yeah, my velocity before was pretty nuts. My passengers hair would be blown around by the port which was ~4 ft away, or whatever it was to the back of of the back seats.

Hunter designed it? It should be alright. As others have suggested, your cabin might be playing more of a factor into this than anything else.