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Thread: The "Share your tune measurements and methods" thread

  1. Back To Top    #11

    Re: The "Share your tune measurements and methods" thread

    I'd be really curious to see how your L+R speaker pair measurements and the overall measurement looks compared to your individual speaker responses, if you happen to get the time to take them.

    I was kind of surprised to see
    a) how different the dB increase was when playing L+R midbass vs. L+R dash speakers (my midbass speaker pairs gained about 6dB compared to individual speaker dB levels, but my mid/high speaker pairs only gained about 3dB when L+R speaker pairs are played)

    and

    b) how certain areas of the L+R responses didn't match the shape of the individual speaker responses - I had quite a few phase- or reflection-induced dips when playing L+R speaker pairs - which I then had to address as another whole round of EQ corrections. Then I had to do yet another round of EQ when all speakers were playing. The end result is that my individual speaker responses no longer matched the curve by the time I was done (but the overall response did). :-)

    A few other things I recently noticed that surprised me a little:

    1. When adding my rear speakers to the overall measurement, it didn't just make the overall response louder in the freq range that the rear speakers play - it actually changed the *shape* of the response quite a bit.
    2. How much the overall response changed when I changed the delay time for the rear speakers. Using a delay of 10ms looked very different than when using a delay of 20ms, for example.
    3. The change in response if I had my windows cracked just 1/2"! It caused areas of the bass response to lose a few dBs!
    4. How different the response looked with relatively minor temperature/humidity changes - mainly with frequencies above ~2khz.

    I'll be posting step-by-step measurements as I go through the entire process shortly.

    I've never used separate target curves for each individual speaker before - I just let REW figure out the individual speaker curves from the overall target curve since it basically just "creates" the individual speaker curves from the overall curve automatically "on the fly" (depending on what you input into the "Target Settings" fields). Just different ways to accomplish the same thing I guess (as opposed to creating separate individual-speaker curves with Jazzis spreadsheet)?

    I find it very interesting to hear how other people do things. :-)

  2. Back To Top    #12
    Noob Brego's Avatar
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    Re: The "Share your tune measurements and methods" thread

    I really enjoy reading your write-ups, you explain your actions and thoughts well, which makes interesting reading.

    I'm in the middle of re-doing my mid-range speakers, i.e., trying different Crossover types & slopes, and Eq'ing from start. I have only a short time to work on it a couple times a week, as I'm helping my elder older brother out... he starting to have a hard time with getting around and doctor visits....

    Give me a few days, and I will post my results.

  3. Back To Top    #13

    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by jtrosky View Post
    I'd be really curious to see how your L+R speaker pair measurements and the overall measurement looks compared to your individual speaker responses, if you happen to get the time to take them.

    I was kind of surprised to see
    a) how different the dB increase was when playing L+R midbass vs. L+R dash speakers (my midbass speaker pairs gained about 6dB compared to individual speaker dB levels, but my mid/high speaker pairs only gained about 3dB when L+R speaker pairs are played)

    and

    b) how certain areas of the L+R responses didn't match the shape of the individual speaker responses - I had quite a few phase- or reflection-induced dips when playing L+R speaker pairs - which I then had to address as another whole round of EQ corrections. Then I had to do yet another round of EQ when all speakers were playing. The end result is that my individual speaker responses no longer matched the curve by the time I was done (but the overall response did). :-)

    A few other things I recently noticed that surprised me a little:

    1. When adding my rear speakers to the overall measurement, it didn't just make the overall response louder in the freq range that the rear speakers play - it actually changed the *shape* of the response quite a bit.
    2. How much the overall response changed when I changed the delay time for the rear speakers. Using a delay of 10ms looked very different than when using a delay of 20ms, for example.
    3. The change in response if I had my windows cracked just 1/2"! It caused areas of the bass response to lose a few dBs!
    4. How different the response looked with relatively minor temperature/humidity changes - mainly with frequencies above ~2khz.

    I'll be posting step-by-step measurements as I go through the entire process shortly.

    I've never used separate target curves for each individual speaker before - I just let REW figure out the individual speaker curves from the overall target curve since it basically just "creates" the individual speaker curves from the overall curve automatically "on the fly" (depending on what you input into the "Target Settings" fields). Just different ways to accomplish the same thing I guess (as opposed to creating separate individual-speaker curves with Jazzis spreadsheet)?

    I find it very interesting to hear how other people do things. :-)
    Your midbass are in phase and summing correctly, your mids should be the exact same with some variations where reflections and phase are causing issues, if they don’t sum with 6db at least in some places chances are phase (or time alignment to a degree, but that tends to be a comb filtering issue) are not correct, try them with zero eq and see if they sum nicer, if so think more carefully about adding lots of eq as that changes phase in itself and also can effect dynamics if way too much is applied, I take a much less harsh approach to eq and smooth rather than flatten with a target curve set in stone

  4. Back To Top    #14

    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by dumdum View Post
    Your midbass are in phase and summing correctly, your mids should be the exact same with some variations where reflections and phase are causing issues, if they donít sum with 6db at least in some places chances are phase (or time alignment to a degree, but that tends to be a comb filtering issue) are not correct, try them with zero eq and see if they sum nicer, if so think more carefully about adding lots of eq as that changes phase in itself and also can effect dynamics if way too much is applied, I take a much less harsh approach to eq and smooth rather than flatten with a target curve set in stone
    This is part of the reason why I'm so interested in seeing other peoples measured responses - to see if they are getting similar results or not. It's almost impossible to find full measurements (where individual speakers, speaker pairs and "All speaker" measurements) are shared.

    When I brought up this summation difference previously, @ckirocz28 provided this feedback:

    "Yeah, you'll be hard-pressed to get that 6 db increase from speakers a car width apart, they need to be within a quarter wavelength of each other to get the full coupling effect. Subs and midbass are fairly easy to couple like that, mids and tweets are not. And the reflections absolutely figure into that problem, and all the other nastiness our cars provide."

    If true, then it would kind of make sense that higher frequencies don't sum to +6dB like midbass speakers would - due to wavelengths, etc... Of course, the specific car layout and speaker locations will play a part too, I'm assuming. In my case, it's a pretty large coupe (Dodge Challenger) and the dash speakers (3.5" coaxials) are at the dash corners and pretty much facing straight up into the windshield - and the top of the dash is huge - like as big as a table. Maybe al of that plays a part?

    I looked back through some of my previous measurements and did find one where I measured left, right and L+R dash speakers with no EQ - and I'm definitely not seeing anywhere near +6dB with my dash speakers (may even be less than the summation I get *after* EQ'ing!). I am positive that my time alignment settings are correct - at least going by measurements (I've measured, re-measured, re-re-measured and confirmed the measurements again). :-)

    Here are the left, right and L+R combined speaker measurements before any EQ. I was testing 350hz crossovers with these measurements (I'm now using 400hz crossovers, just FYI):



    Hopefully, some other will provide their measurements for comparison. If so, please try and provide the general speaker layout as well (on/off-axis, etc) - I think that would be helpful information to include.
    Last edited by jtrosky; 2 Weeks Ago at 08:01 AM.

  5. Back To Top    #15

    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by Jdunk54nl View Post
    I apparently didn't save my tweeter measurements or speaker pairs/overall on this day, but here is my most recent tune. On average this uses like 3-5 bands of EQ for each speaker.

    I use a 90 degree cal file from cross spectrum labs and a dayton usb mic and REW. I wave the mic completely at random. Currently I sit in the drivers seat and do this, but after talking with Erin on his post and Justin, I think I am going to try sitting in the rear seat and doing this.

    I use Justin's tuning companion to load house curves

    I use whatever slope, crossover type, frequency needed to match the acoustic 24 db LR curve and protect the speakers.

    My current sub to midbass crossover is 100hz. For some vehicle/reflection reason I can't get anything to play much under 100hz without falling off from my doors in my listening position (they play way below when measured close to the speaker).

    My midbass to midrange is 350hz
    My midrange to tweeter is 3500hz

    First picture is just the speakers, the second includes the house curves loaded

    Attachment 9842

    Attachment 9841
    Curious about the part where you mention trying tuning while sitting in the back seat. Do you mean for tuning the rear speakers (for passengers sitting in back)? Or if not, interested to know the thought process behind this. Thanks!


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  6. Back To Top    #16
    Noob Jdunk54nl's Avatar
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    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by mauian View Post
    Curious about the part where you mention trying tuning while sitting in the back seat. Do you mean for tuning the rear speakers (for passengers sitting in back)? Or if not, interested to know the thought process behind this. Thanks!


    Sent from my iPhone using Tapatalk

    Look at ErinH's thread on the fan moving mic rig. It was discussed in there.

    Basically I would sit in the back and hold the mic in the drivers seat, to eliminate my body the best I can without building that fan mount.
    2014 F150 Limited -> Factory HU programmed for 4v outputs -> Helix DSP.2 -> Alpine PDX-V9 -> SI M25 in Valicar Stuttgart Pods, Rear SB17's, Sub BM MKV's in MTI BOX. Alpine PDX-F6 -> SI TM65 MkIII, SI M3 in Valicar Stuttgart Pods

  7. Back To Top    #17

    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by Jdunk54nl View Post
    Look at ErinH's thread on the fan moving mic rig. It was discussed in there.

    Basically I would sit in the back and hold the mic in the drivers seat, to eliminate my body the best I can without building that fan mount.
    Ah, cool. Will take a look.


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  8. Back To Top    #18

    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by erinh View Post
    I posted a lot of Tuning related information in my old car's build thread. Starting with Post #11 here: https://www.caraudiojunkies.com/show...ght=2006+CIVIC

    But, unfortunately, I guess those photos are no longer available. Still, there's a few good posts in between in there. So, I can say I definitely had no problem sharing... at least back then. Once I start actually tuning in my car again I'll make sure to post that info in my new build log.

    Also, you guys might be interested in this if you haven't seen it:
    https://www.caraudiojunkies.com/show...r-RTA-purposes
    Hey Erin,

    With the MMM did you find that facing the mic forward was better than facing it up? Or how did it differ and what do you use now?

    Thanks!


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  9. Back To Top    #19

    Re: The "Share your tune measurements and methods" thread

    I'm not really sold on the whole "measure without being in the drivers seat" thing. I guess I'd rather know the measurements *with* me in the drivers seat since I'm *always* going to be there while actually listening to music. I just don't see the advantage of measuring (or hearing) things without a body in the seat that is going to be there otherwise - it will never be accurate.

    I get that most target curves aren't "designed" with a body in the seat, but a target curve is just the "starting point" anyway - and then you adjust for preferences from there (or in my case, I actually do create a target curve from my actual measurement after I get the sound I'm looking for).

  10. Back To Top    #20

    Re: The "Share your tune measurements and methods" thread

    Quote Originally Posted by jtrosky View Post
    I'm not really sold on the whole "measure without being in the drivers seat" thing. I guess I'd rather know the measurements *with* me in the drivers seat since I'm *always* going to be there while actually listening to music. I just don't see the advantage of measuring (or hearing) things without a body in the seat that is going to be there otherwise - it will never be accurate.

    I get that most target curves aren't "designed" with a body in the seat, but a target curve is just the "starting point" anyway - and then you adjust for preferences from there (or in my case, I actually do create a target curve from my actual measurement after I get the sound I'm looking for).
    I see what youíre saying. I suppose target curves werenít designed for dashboards like tables and other obstacles found in a car which we canít remove?

    A body seems like one more object in the car that canít be removed when listening to music in that environment. It would seem we would want to hit a target response that our ears would experience with all the obstacles in the room that would normally be there. Weíd want to account for these obstacles that are interfering with and changing the sound, no?

    Similarly, Im not sure why it would be useful to tune a car with the steering wheel removed and emergency break lever removed if they are always going to be there...like our body. I might, and very well could be missing something though.


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