Help With Tune Please

[Cathul]

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?

Just make consecutive measurements of all drivers, midbass and sub without any EQ and crossovers (and after that with everything turned on) at the same volume level and then save the measurements.
You will have lots of measurements in the left part of REWs window and they will all have the same relative volume and in the "All SPL" tab you can then see the acoustical crossover.

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.
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Raise the volume on the headunit.

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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?

Basically, yes.
And that's what you need the measurement without crossovers and EQ for.
In REWs EQ window you can then try different crossover simulations to bring the slope near the desired ideal slope of the target curve.
The acoustical curve should be a LR24db as this gives the least problems with phase in the crossover region. Two acoustical LR24db slopes will be in phase in the crossover region.
But, you can surely use a BW12db electrical filter, or an 18db filter, or a 12db LR or whatever make the acoustical measured slope match the desired acoustical slope. By doing this you may achieve lot less EQ in the crossover region.
Ideally you want to use the same crossovers on both sides, but it may be that you have to use different crossovers for your left and right midbass.
If the acoustical crossover matches this shouldn't be too bad, although it is not ideal in my opinion.

[Student Sound]

Thank you very much for the advice. I just want to clear up one thing before moving forward. If I take measurements using mono pink noise with all crossovers and eq settings disabled I won't damage my speakers?

[Cathul]

Thank you very much for the advice. I just want to clear up one thing before moving forward. If I take measurements using mono pink noise with all crossovers and eq settings disabled I won't damage my speakers?

Set a steep crossover (24db electrical) on the tweeters at 1.5x fs to give them protection and you're good to go.
And you won't damage your midbass speakers if you're not going crazy with the volume knob while measuring.

[Jdunk54nl]

Thank you very much for the advice. I just want to clear up one thing before moving forward. If I take measurements using mono pink noise with all crossovers and eq settings disabled I won't damage my speakers?

Set the gb 10 at like 2000hz with a 24db crossover

Set the gb25 at like 150hz with a 24db crossover

No crossovers on the gb60

No crossovers on the subs

Then I personally like to sit in the back seat, recline the drivers seat all the way down, put my microphone on an extension (like a 1x1 board that is 4ft long) and play mono pink noise and measure each speaker moving the microphone around my listening area. I recline the front seat based on reading Floyd Toole's work on measuring theatres and the issues of using the microphone close to the headrests of the theatre seats. The seat causes reflections our brains can't hear, but our microphones pick up. So remove it and you remove the microphone picking up those reflections, then when the seat is back, we do not hear them anyway.

I then get out of the truck, go inside where it is much cooler (I live in phoenix) and use REW to EQ everything. I do all manual EQ now but their auto eq works ok.

- Once in the EQ window, turn off all but the predicted curve and target curve (See light green circles in the bottom middle of the picture).

- Make the Frequency response take up as much room as possible (use the little arrows on the bottom left to close the bottom screen as circled in red)

- Set your crossovers on REW first by hitting the EQ filter button (even before if you use Auto EQ) in the top middle of the screen. Scroll all the way to the bottom.

- You can see on the right side, my house curve wants a 130hz 24db/oct ACOUSTICAL crossover (as in measured by a microphone in my listening position).

- In the EQ filters window at the bottom, also circled in blue, you can see BU2 or Butterworth 2nd order (2nd order means 12db/oct) at 100hz ELECTRICAL crossover is what I would need to enter into my dsp to get that to happen. This is because the electrical setting and the natural roll off of the speaker combine to form that 24db/oct I want.

Do note, this was a home bookshelf speaker that I built and was measuring. This wasn't my final work but what I could find easily and illustrated the point. I wouldn't use the target settings window on car speakers, I would import the house curve using Justin Zazzi's REW helper spreadsheet. A single bookshelf speaker is just easier to do this way for me. Car speakers 100x easier using Justin's spreadsheet.







Just for reference, if I put in an electrical setting of 130hz 24db/oct, you can see the acoustical response falls off way too quick, as in it is like a 30db/oct slope (at 100hz it is 64db, at 50hz it is 34db or 30db change). This would impact the phase and make it harder to get the speakers in phase with the subwoofers. I want to spend as little time as possible messing with open sound meter or smaart to get my phase right. The above picture would allow that. The below picture would require more phase alignment work and some "trickery" to get it right, and it would probably still be off compared to the above.

[Cathul]

Don't use "Bass limited speaker" in the EQ window of REW. Use "Speaker Driver" instead as this gives you the option to set LR24db acoustical crossover slopes instead of the default Butterworth for the target curve (the blue line in Jdunks screenshots).

[Jdunk54nl]

Don't use any of those on a car. Import the house curve from Justin's spreadsheet and set REW to none.

For my home, if you set to speaker driver, you can't add a room curve, and I wanted to match the gentle slope from low frequencies to high that you would expect in a room.

[Cathul]

You can. I do it all the time. I even imported the single driver curves from the spreadsheet and compared it to the speaker driver curve in REW after i loaded the overall target curve in the preferences. Ideal curve was identical to the imported single driver target curve.

[Jdunk54nl]

You can. I do it all the time. I even imported the single driver curves from the spreadsheet and compared it to the speaker driver curve in REW after i loaded the overall target curve in the preferences. Ideal curve was identical to the imported single driver target curve.

The problem with the speaker driver REW curve compared to Justin's spreadsheet, is his spreadsheet takes into account all parts of the total curve. You can't do, for example, a dip between 2khz and 4khz, and have REW account for this in the individual speaker curve. His curve being imported does account for this and takes and makes the individual speaker curve appropriately for that change. Similar issues with high frequency roll off and bass increases.


If I am wrong about this, please let me know how you can. Same as if you can add a "room slant" to the curve with a speaker driver like you can with a bass limited speaker. You can see in my pictures above, I have the slant at 0.6db/oct slope from low frequencies to highs. This is matching the natural roll off that should be predicted in a room. A completely flat response would be unnatural in a room and would probably mean the speakers would have too much energy at the high frequencies aka a "bright" speaker.

[Cathul]

If you set Jazzi overall curve in preferences as the house curve this exact curve is used to calculate the ideal response and slopes in the EQ window when you select speaker driver and set the acoustical crossovers for this ideal curve.



Try it yourself and be amazed.

[Jdunk54nl]

Well I'll be....REW must have changed how that worked because it never worked like that before (I haven't tried in a few years after the first time I tried and it very well could have been me making a mistake somewhere too)! Thanks for the tip!

Just did it with a midrange, normally when this would happen it would just be like the 2nd picture and not the first.

Still can't do room tilts unfortunately unless you have a house curve loaded that already has one.