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Discussion Starter #1
I can’t tell ya how many times I’ve taken measurements made the adjustments say -1.6db at 1700hz or whatever go back and measure to check and find now I have to add the 1.6db dB back to hit the target response. Then I Take another measurement to check the adjustment and find it needs the 1.6db cut again!
What would cause this back and fourth? I have spent I bet 200 hours in my car this last year tuning and trying different things. And this is one thing I can not figure out.
Could it be my laptop needing more processing power?
Or possible need to change some settings in REW when taking measurements. I’ve tried different overlaps, update intervals and so on. I have yet to see a consensus on which settings is best.
 

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Are you always measuring at the same volume?
And how much of the band is changing, just one or two frequencies?

Could be a flaky microphone, I wouldn't think processing power would do anything.

What equipment are you using?

Sent from my Pixel 3a XL using Tapatalk
 

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How many measurements are you taking to get your average, and are you taking them at roughly the same spots each time?
 

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I’ve seen that before and it puzzles me too but I think it has something to do with the temperature of the mic diaphragm, that’s what I can sum it up to because if I do a measurement in the morning when it’s colder I get a few peeks and valleys and in the evening I have to put them back where they were so I stopped messing with my system all together for the winter. Try measuring it at the same temperature at all times and see if it does the same thing, just a suggestion as I’m not a pro.
 

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Discussion Starter #6
i have Noticed the temp related changes.
I’m doing the ear to ear technique for about 200 averages.

I use a umik.

And roughly the same spots will and can result in huge differences in the higher frequencies. Do y’all use a jig or something.
 

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Discussion Starter #7
I can’t seem to get to take the sweep measurements with my laptop. If I hook up the aux cable it produces alot of noise . Can sweeps be ran via Bluetooth from laptop to headunit?
 

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I have a high noise floor using aux as well, but I think the signal level negates this when running a sweep. I've been averaging about 8 sweeps with REW.
 

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Discussion Starter #9
It’s more than hiss though it buzzes.

Can you all see my signature with equipment. I get asked in every thread but I can see it and it’s been set up for a while now
 

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A lot of people use the Tapatalk app for forums, which doesn't show signatures, so that is probably why a lot of people don't see them. Tapatalk makes forum browsing so fast - all forums have the exact same interface - which is mainly just the posts without all of the advertisements, signatures, web-site graphics, etc (which is why it's so fast). I couldn't go back to using the website versions of forums again. :)

EDIT: Plus, the default on the new software is to only show the first line or two of the signature - and a lot of people probably don't change the setting and don't click to "expand" the signature manually.
 

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Record the sweep to a usb with timing chirps if required, and then play it back from usb while telling rew which file your using also 👍🏼
 

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Discussion Starter #12
Ok. How would I record it with sweeps? If that would work that’s awesome. Thanks!
 

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Discussion Starter #13
Just spent 2 hours messing with REW trying to tweak out a few things and it was doing it again. Make a couple adjustments on a tweeter. Then measure to check only to find out now it says exactly what I just did needs undone to hit the target. This makes zero sense. Something is flawed. The mic, or this moving mic measuring technique is it so reliable. I always try to be sure to hold the mic the same and sweep ear to ear the same. And have been trying to make it perfect for a over a year and this weird situation always seems to start happening. There has been a few days where it did not do this but I wasn’t doing anything different!

anyways about to go back out because now it’s all messed up 😡
 

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Discussion Starter #14
I took [email protected] Qof 5 off of the response in the red. So why did the rest of the response change? This is just one example. but it happens almost every other measurement. About to have to give up before it drives me insane. Over a year of this crap. When I continue in the morning, it is 1000000% certain nothing will look like it when I finished for the night.



263514
 

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Discussion Starter #15
What I need to know is for taking the moving mic measurement. What settings do I need to be using?
update interval, max overlap and anything else that matters.
Do you all take the measurement with a smoothing being applied? Or do you take it with no smoothing then add the smoothing after you took the measurement in another screen?

currently my settings for taking measurements are
1/48th octave, (i just realized this does not say smoothing) smoothing is greyed out in the option below this option.
FFT length 64k
averages forever
window rectangular, max overlap 87.5 (have tried other options but see no difference in final result)
update interval 1
 

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Discussion Starter #16
What I need to know is for taking the moving mic measurement. What settings do I need to be using?
update interval, max overlap and anything else that matters.
Do you all take the measurement with a smoothing being applied? Or do you take it with no smoothing then add the smoothing after you took the measurement in another screen?

currently my settings for taking measurements are
1/48th octave, (i just realized this does not say smoothing) smoothing is greyed out in the option below this option.
FFT length 64k
averages forever
window rectangular, max overlap 87.5 (have tried other options but see no difference in final result)
update interval 1
 

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You can use the signal generator in rew to record a sweep to your pc, then when you go to measure (not rta!) you then add the sweep to a usb and point rew towards the file on the pc also, then your stereo plays the sweep from the usb and rew knows what to look for from the measurement mic and starts the measurement when it hears the first chirp and then the sweep after
 

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As for your measurements being with 1/48th octave, that’s down to your setting (if you choose spectrum analyser you can choose a smoothing option), you can also set the smoothing in preferences to be applied once you save the measurement from the rta...

if your measurements aren’t consistent your measuring technique isn’t consistent, simple as that 👍🏼

I’d choose to apply variable smoothing as you need less smoothing at lower frequencys 👍🏼
 

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The umik-1 has an accuracy of +/- 1db. 1.4 db is not far off from the margin of error.

Get things as close as you can and when you get to the point where inconsistent results are occurring, then you are at the limits of the equipment and day to day variations caused by temperature and humidity (air density).

The big question is can you hear the difference between that 1.4 db adjustment when listening to music? I will guess no. If the system sounds good, I would just enjoy it knowing that youve tuned it as best as possible given the environmental conditions and equipment limitations.

There are far too many other factors out of your control while driving down the road which will have a greater influence on your response curve than that 1.4 db difference.

Also acoustic waves are interfering inside the car. Dropping one frequency can affect the other frequencies slightly.
 

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I no longer chase the "perfect" curve.
It's a starting point.

After you get there, you should listen for things you like or don't like, then raise or lower that band and listen some more.

Our ears aren't equivelant to a microphone.

One prime example, 1k-2k being flat is percieved by most people as too much. Our ears are more sensetive in that area. We developed that over time because that's around the frequency of a baby crying.

Once I lowered that a notch or two the harshness of my system vanished.

Just one example.

Recordings are all not the same either.
I'll raise or lower the tweeters and subwoofers up to 3 notches because the song needs it.

The mic shows you big problems and makes it easy to see the full picture, but in the end you are trying to please your ears, not the picture on the screen.

Sent from my Pixel 3a XL using Tapatalk
 
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