Tuning guidance: 2-way Bass to Mid to Tweet relationship

[chiefgeek]

I tried to follow the Audio Frogg guide for having front bass.

12" (Alpine Type S) crossed at 60
6.5" Mids (NVX XSP65) 80-2500
Tweeters (NVX VSPTW) 2500

Crossovers are stacked LR-12db (mosconi DSP)



I feel like there is no mid-bass in the system if I lower the sub level the then there is no bass.
Questions:

1. Peak at 40hz, is this just an artifact of the vehicle?
2. There is a drop in level from 300hz on the midbass curve, is this something I am something I am doing wrong?
3. There is a dip from about 1700-2700, should I be bringing the rest of the system down to that level?

[JCsAudio]

Ahh, I’ve god a decent amount of experience tuning a two way. Here is my guess on what is going on and answers to your questions.

#1 This is most likely cabin gain, typically in the 40-50 Hz range, and can be tuned out with the DSP by cutting EQ centered at 40 Hz.
#2 That dip at about 500 Hz looks like the typical cancellation node caused by the midwoofers location in the door and the front sound wave bouncing off the center console and back at the mid woofer causing cancelation which almost always happens at around 400-500 Hz. It has to do with the midbass location and how far it is from the center console. This is especially true if it doesn’t respond to EQ boost at that dip. There isn’t much you can do about this really except relocate the midbass or go with a three way setup where you can cross from midbass to midrange lower than 400 Hz. Sometimes if you have enough headroom with your amplifier you can cut everywhere else around it and lessen the effect.
#3 The dip centered around 2500 Hz which so happens to be the crossover from your midbass to tweeter looks like a phase issue. You likely have those drivers out of phase with each other. If you’re using 24 db Linkwitz Riley crossovers (highly recommended) then flip the phase of the tweeter and remeasure. If that dip evens out or improves then your speakers had reversed polarity which means the pus and minus somewhere is mixed up.

[SkizeR]

I noticed you mentioned stacked 12db LR Slopes. Just a heads up, two 12db butterworth slopes create a 24db LR slope.

"Peak at 40hz, is this just an artifact of the vehicle?"

Yes


"There is a drop in level from 300hz on the midbass curve, is this something I am something I am doing wrong?"

this is just part of audio in a car and why a powerful eq is pretty much necessary to achieve good sound in a car.


"There is a dip from about 1700-2700, should I be bringing the rest of the system down to that level?"

I wonder if thats crossover cancellation. Try reversing phase of both tweeters and measure again. compare the two measurements and see if the dip goes away or is exacerbated. But, i have never seen crossover cancellation THAT bad at frequencies that high, so idk

[chiefgeek]

I noticed you mentioned stacked 12db LR Slopes. Just a heads up, two 12db butterworth slopes create a 24db LR slope.

Hmm. The mosconi UI says if you want a 24db slope create 2 identical 12db slopes. I am trying the 2 Butterworth 12db.

"There is a dip from about 1700-2700, should I be bringing the rest of the system down to that level?"

I wonder if thats crossover cancellation. Try reversing phase of both tweeters and measure again. compare the two measurements and see if the dip goes away or is exacerbated. But, i have never seen crossover cancellation THAT bad at frequencies that high, so idk

Hopefully it is because of the crossover types causing out of phase issues

[chiefgeek]

#3 The dip centered around 2500 Hz which so happens to be the crossover from your midbass to tweeter looks like a phase issue. You likely have those drivers out of phase with each other. If you’re using 24 db Linkwitz Riley crossovers (highly recommended) then flip the phase of the tweeter and remeasure. If that dip evens out or improves then your speakers had reversed polarity which means the pus and minus somewhere is mixed up.

I tried swapping phase on 1 tweeter and didn't notice a difference.

[chiefgeek]

So, after trying stacked butterworth 12db crossovers and a little more tweaking, this is what it looks like but it still sounds like sh*t, I think it lacking mid-bass because I hear the tweeters and sub occasionally but nothing from the doors (tweeters are a pillar, mids in lower door panel)

[SkizeR]

to be blunt, that is a horrific curve. You have a 45db swing from 30hz to 1.8k. i think its time to read the audiofrog tuning guide and start fresh

[chiefgeek]

to be blunt, that is a horrific curve. You have a 45db swing from 30hz to 1.8k. i think its time to read the audiofrog tuning guide and start fresh

Im glad to hear that. Thanks I will read it again and start over, hopefully I will get a better result next time.

[SkizeR]

For reference, having a 20db swing from 20hz to 20k is pushing it. 25db is getting to the realm of unrealistic. 45db is just absurd lol

Sent from my SM-G975U using Tapatalk

[chiefgeek]

I had a little time to mess with it this afternoon and it sounds much better, here is what I have now. Not sure if I got the left and right close enough together.