Help With Tune Please

[Student Sound]

I'm a novice when it comes to car audio and this is my first system ever. I've attempted a tune using information that's available on the internet. I was hoping the members here could help me with additional tuning. I'm not even sure what to post but I see this graph from REW posted often so I'll start with that. What additional information is needed to critique my tune? Would individual graphs for each speaker be a better start?

Any and all help is greatly appreciated!

[Cathul]

Yes, individual measurements for each driver would be a great start including the raw measurements before setting EQ and crossovers.
What electrical crossover settings do you use?
Maybe even attach the MDAT file from REW or make it downloadable from any location.

At first look it looks like you got some serious phase issues between midbass and subwoofer.
So please also post the settings for time alignment with the corresponding tape measurements.

[Student Sound]

-24db linkwitz

All my measurements were done after setting crossovers and TA. I didn't know I was supposed to take measurements before. I read that there was a possibility of damaging speakers if crossover weren't set properly.

I used a tape measure and measured from each speaker to my head for TA. I measured the back of the sub box to my head when I did TA for the sub. I measured through the access panel in the back seat.

Here's all my measurements before and after eq. https://drive.google.com/drive/folde...tz?usp=sharing

Here's the TA numbers from my dsp.

Driver side woofer
92.08 cm
36.25 inch
1.56 ms

Passenger side woofer
137.42 cm
54.10 inch
.23 ms

Sub
145.21 cm
57.17 inch
0 ms

Midbase

Before eq


After eq


Sub

Green is before and purple is after.

[Julian]

Sending a full range signal to tweeters will fry them unless you put a capacitor in.
What speakers are you using?
GB60 and what sub? No tweeters?

[Student Sound]

gb10
gb25
gb60
gs25 - center dash
gs62 - rear fill
gb12d4 - just 1 for now

[Cathul]

Thanks for the measurements, but as you've put them into individual files you lost the relative information between drivers, i.e. i cannot see at what level the drivers are at, and therefor not the acoustical crossover points.
You also didn't mention the crossovers, except for the slope, but not frequencies for low- and highpass.
When i just open the measurements without the information about the gain between drivers I see you have an acoustical crossover of about 125Hz, is that correct (probably not, but shows the problem)?
So please make measurements with the same volume on the headunit and within one mdat file, so we can directly see the acoustical crossover points in REW.

What is causing that spike in the midrange EQed responses around 35Hz? Have you loaded a calibration file?

When I simulate a LR24db crossover at 80Hz and 300Hz with my housecurve it looks like this compared to your drivers midbass.



So you're missing some volume between 60Hz and 120Hz. What is your midbass highpass set to? If it's set at 80Hz, then the slope is too steep for an acoustical LR24db alignment. Either try a lower frequency or a shallower slope like BW 12db and remeasure. Slope on the sub seems to be correct, but as said before, I cannot really see where you've set your acoustical crossover at.

[jrwalte]

So you're missing some volume between 60Hz and 120Hz. What is your midbass highpass set to? If it's set at 80Hz, then the slope is too steep for an acoustical LR24db alignment. Either try a lower frequency or a shallower slope like BW 12db and remeasure. Slope on the sub seems to be correct, but as said before, I cannot really see where you've set your acoustical crossover at.

To further explain this, as it took me awhile to understand it, the crossover you set in your DSP does NOT have to be LW 24dB. What you're trying to achieve is what looks like a LR24dB slope on your RTA measurement. The 'acoustical' crossover, as Cathul said. Your 'electrical' crossover can be whatever it needs to be in order to achieve that. Justin Zazzi has made a spreadsheet that makes it very easy to determine what your LR24dB acoustical crossover should like like between your sub and mid.

https://www.caraudiojunkies.com/show...t=justin+jazzi

[Jdunk54nl]

Thanks for the measurements, but as you've put them into individual files you lost the relative information between drivers, i.e. i cannot see at what level the drivers are at, and therefor not the acoustical crossover points.
You also didn't mention the crossovers, except for the slope, but not frequencies for low- and highpass.
When i just open the measurements without the information about the gain between drivers I see you have an acoustical crossover of about 125Hz, is that correct (probably not, but shows the problem)?
So please make measurements with the same volume on the headunit and within one mdat file, so we can directly see the acoustical crossover points in REW.

What is causing that spike in the midrange EQed responses around 35Hz? Have you loaded a calibration file?

When I simulate a LR24db crossover at 80Hz and 300Hz with my housecurve it looks like this compared to your drivers midbass.



So you're missing some volume between 60Hz and 120Hz. What is your midbass highpass set to? If it's set at 80Hz, then the slope is too steep for an acoustical LR24db alignment. Either try a lower frequency or a shallower slope like BW 12db and remeasure. Slope on the sub seems to be correct, but as said before, I cannot really see where you've set your acoustical crossover at.

This could be the cause of the 60-120hz issue, although that is pretty wide for this issue. The crazy amount of rise below 60 out of the midbasses is also pretty interesting.

https://www.youtube.com/watch?v=aIAV-jDafq0&t=1s

[Student Sound]

Cathul

gb10 - 3k to 20k
gb25 - 300Hz to 3k
gb60 - 80Hz to 300Hz
sub - 20Hz to 68Hz

Just to be sure I would need to take measurements of my speakers in their current eqed state at one volume level? How do I turn it into 1 mdat file?

I have no idea why the response spikes at 35hz. I honestly didn't even give it a second though because it was out of the speakers range. Could it be noise from outside the car? I'm measuring with a UMIK-1 using the 90deg calibration file.

I think I understand what you and jrwalte are try to say. I should try using -12db and then tune within REW to a -24db slope using the selectable settings? If that doesn't work I should move the cutoff down to 70 instead of 80?

jrwalte

I think I understand what you're saying. I should try using -12db in the dsp and if that fixes it then tune to -24db in REW? I'll look into Justin's program too.

jdunk54nl

I initially brushed the dip off thinking it was some kind of null or cancelation from me sitting in the drivers seat. I now know that isn't the case.

[jrwalte]

We're saying it could be anything. It doesn't have to be 80 Hz crossover or even matched between the sub and mid (they don't have to both be the same #). You can mix and match crossover types too and use LW on the mid and BW on the sub, for example. You just have to make sure you aren't causing it to be out of phase and you know this by seeing a dip around the 'acoustical' crossover you're shooting for, typically 80Hz 24dB LW.

A big part of your null looks like your 68Hz crossover of the sub. Try raising it.

In your last graph of the mid test, you should raise the volume. The results should be 75+dB I'd say. I think you see the jump in the low end because you're near the noise floor.