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Discussion Starter · #1 ·
Here's my setup:
Sony 9500 feeding a stereo pair to a DSP.3S feeding 4 channels to a Biketronics BT180 feeding a two-way implementation of NZ3 wideband and SK8 woofer.

That's it. Simple two-way setup.

I've learned that the Audiotec-Fischer software has built-in time alignment and automatic RTA. I tried this and got what I consider really good results! The thing is, I've never done this before and have no frame of reference to another SQ system. I have a very deep and broad technical background with engineering/programming and have built my own home speakers from the brain of the late Sig Linkwitz of Linkwitz-Reily fame. So, I already know I'm using L-R 4th order 24-db crossovers.

I'm working my way through the Audiofrog tuning guide. And I love how detailed the author is. I know a lot of this already, but it's helpful to review.

So, the first thing I did after I hooked everything up is let the software use my MiniDSP calibrated microphone to set the timing and RTA. It worked pretty well, but in the back of my mind I'm wondering if this is the stopping point, or the starting point to further manual tweaking.

I realized my automatic seat didn't get repositioned to my set memory location when I did the first run, so I need to re-calibrate using the proper seat location since it's about 60cm difference.

I'm still playing around with the proper cross-over point. I started out at 250hz, and changed to 550hz after the automatic RTA was maxing out sliders trying to boost the 800hz range. 550hz seems to have gotten me closer but the software still complains it's not able to solve the equation satisfactorily. As smart as this software is, it doesn't seem like that much of a leap to go ahead and automatically set the cross-over points, right? Maybe a future release.

In the first calibration I pointed the microphone straight up and used the 90degree calibration file. Is that preferable to the straight-ahead calibration?

Finally, with my set-up, do I want to research the virtual channel processing? I'm not exactly sure what that gets me in my simple setup. All of my source material will be originating at the 9500, which only provides an analogue signal.
 

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It could be the start or the end. What you just did will satisfy 90% of listeners. Unfortunately everybody on here is the other 10%. First thing I would do is to select crossovers based on how the speakers interact with each other and the car environment. To do this set crossover for tweeter at 1500 Hz. HP and 40 Hz HP for the woofer and none for the sub. Do not play very loud because you do not want to blow your speakers, and you could at those settings. Record each speaker into REW. You will be able to see where the speakers roll off naturally. Choose a crossover where there is overlap and stay away from the natural roll off. Then do TA and EQ. The Helix auto TA and auto EQ are half decent. Do not change crossovers once TA and EQ are done.
 

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Discussion Starter · #3 ·
I pulled 250hz to 650hz as the overlap from the published polar charts. I take it you have to use REW for each individual environment since the acoustic environment will be different for each vehicle. ok, easy enough, I've got REW installed, so I just need to learn its basics.
 

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You won’t get that 8” to play up to 1500hz. I’d take some measurements in rew and see what the speakers rta looks like. 550hz sounds ballpark for your 8” and wideband.

Edit. Stycker is suggesting crossovers just for viewing in rew. You don’t have a tweeter so set your wideband for 200-250 hp just to see what it measures.
 

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Discussion Starter · #5 ·
@DaveG That triggers another question... Does the cross-over point need to be the same for both drivers? I just realized they might need some overlap, so maybe 550hz with the SK8 and 250 for the NZ3?

I guess with DSP, it's more of a roll-off frequency for each driver than necessarily a cross-over point to the other driver. Of course, I'm not giving any due to the phase issue, so I know it's more complicated than just that.
 

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Overlap no bueno! Your 8’s will start to beam if you go too high. I’d see what they rta and set crossovers from there. And use 24dB LR and no overlap.
 

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You won’t get that 8” to play up to 1500hz. I’d take some measurements in rew and see what the speakers rta looks like. 550hz sounds ballpark for your 8” and wideband.

Edit. Stycker is suggesting crossovers just for viewing in rew. You don’t have a tweeter so set your wideband for 200-250 hp just to see what it measures.
Your right, I did not notice it was a wideband. Do the same thing and use 150 Hz on the wideband. Again, do not play it too loud as 150 Hz could potentially damage that driver. Play the wideband as low as you can. If it rolls off naturally at 200 Hz then try 300 or 350 Hz as a starting point. I use 90 degree calibration file, but I'm not sure that matters much. I use the Virtual channels for Global tuning once the individual channels have been tuned.
 

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Discussion Starter · #8 ·
I think it did it correctly and there was a point right between 350 and 400 that looked optimal. Due to slider points, I ended up at 376, which seems to work pretty well. I ran the input analyzer, then did the automatic time alignment, and finally did the RTA. I ran it a few times widening the overall frequency band, first 160 to 8000 and finally 50 to 16000, and I got within 0.7db of the target curve over that wide range.

I pointed the microphone directly forward exactly inside the spot where my ears would be. A.F. mentioned something about pointing the microphone straight up and moving it in a circle between where the ears are. I'm going to have to ponder that a bit. I'm not sure if that's for a real-time measurement, or just to dial in the sufficient volume. I just turned it up to 21 (out of 50) and that was a green bar all the way across the top so I figured that was good for now.
 

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Those crossovers points sound more in line with what I was thinking too. Glad you got it! FYI in the future you can just enter the crossover point instead of using the slide bar but make sure you hit “enter” after.
 

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It could be the start or the end. What you just did will satisfy 90% of listeners. Unfortunately everybody on here is the other 10%. First thing I would do is to select crossovers based on how the speakers interact with each other and the car environment. To do this set crossover for tweeter at 1500 Hz. HP and 40 Hz HP for the woofer and none for the sub. Do not play very loud because you do not want to blow your speakers, and you could at those settings. Record each speaker into REW. You will be able to see where the speakers roll off naturally. Choose a crossover where there is overlap and stay away from the natural roll off. Then do TA and EQ. The Helix auto TA and auto EQ are half decent. Do not change crossovers once TA and EQ are done.

Can you tell me more about auto tune helix?

Why do you say half decent. I haven’t used it , tune a lot of cars , heard a car that was amazing that used it.


What are its pitfalls would you say?
 
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