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Discussion Starter #1
Any tips? What's the best compromise for both the driver and passenger while giving the driver somewhat of an edge given that the time alignment will be for the driver, but that the tonal balance is good both for the driver and passenger.


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I did this in my vette...put your mic in the center spot between the two seats. Your tune is now aligned for the center, so both people hear it the same, albeit mirrored. VXi gives you the ability for several different tunes, so once the tune is straight, you can adjust for time alignment to any position you want. Easy peasy.
 

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Basically get your pld down to under 10” (.83ms) or abouts is ideal



Otherwise , for two seat tune takes some trickery and some settling on some big compromises on the center being solid and that is directly related to how low you PLD numbers are.


1. Use a 2nd order all pass with a Q between 1 and 1.4 centered between 200-300 (depending how wide your car is and those PLDs

Listen on both sides with no EQ applied against left and right. Whatever EQ you have make sure it’s the same for both sides together

Get the center for both sides to sound as much as possible with that all pass

(It won’t be awesome but will be better than it was)

2. Carefully use EQ and gain and jump back and forth on each side and listen.

You want to listen for the frequencies that promote the center / left / right using a relative polarity track.

3. Use asymmetric crossovers if it helps get things working better. The time shift on the crossover can be used as your advantage to help move things a little.

Work on all of the above from 250hz to 1.3khz

4. Using eq shape the amplitude above 1.3khz to promote stage.

5. Use delay and polarity flips in all kinds of crazy ways. Make small changes. Stay within the limitations of the frequency dependence of that passband. (You have to convert milliseconds to feet and to frequency......) a mid to midrange with a crossover of 300hz could be as much as 1.6ms difference from actual distance.

6. Do all of this in no specific order. It’s a matter of making good judgment on what needs what as you listen.

7. If PLD is under .5ms good chance the AllPass won’t be needed at all.

8. Make whichever pair of speakers that has the least PLD be the first to arrive
By using delay (use the hass effect to your advantage) this is not a necessary step but can help quite a bit on lower midrange.


This is the Non-FIR approach that works decently.
You should get both sides to have

a. Non biased sides
b. Spectral balance on both sides

You probably won’t have a super solid center , it will be very diffuse and probably be midbass heavy (200-450hz) and the flatness if desired response may be unachievable if you PLD is too large. If you can get your PLD under .5ms the stage can be easier and easier and better and better the closer you get to no PLDs. If you PLD is under .5ms you can have just a good a stage as a one seat tune in every fashion and in my opinion it’s better than using a bunch of delay on one side.
 

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I’m using the Real Center upmixing capabilities of a Helix Mini with favorable results. I’m semi-active 3-way left and right. So, passive between midranges and tweeters w/midbasses on their own channels. The center is also passive between same midrange and tweeter as left & right. The last channel of DAP is for the sub.
 

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Discussion Starter #8
I’m using the Real Center upmixing capabilities of a Helix Mini with favorable results. I’m semi-active 3-way left and right. So, passive between midranges and tweeters w/midbasses on their own channels. The center is also passive between same midrange and tweeter as left & right. The last channel of DAP is for the sub.


How does that sound when something is hard pan right or left? Santana - black magic woman

Or Hotel California MTV live performance is a good song to check.

I was curious how good real center processing from the Helix is. Wonder if it's better than Dolby PL2 or maybe even Logic7.


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Discussion Starter #9
Not that easy sorry.



Wouldn’t that be nice tho ;-)


Hahaha this.

Folks, if you don't know for sure or haven't tried something please don't lead me into the wrong direction. Much appreciated.


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Hahaha this.

Folks, if you don't know for sure or haven't tried something please don't lead me into the wrong direction. Much appreciated.


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Ummm...I've tried for sure. The center position tune is my 3rd preset. It was literally as easy as time aligning for the center position. But hey...if you want to complicate the hell out of it for no reason, more power to you.
 

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I hear you tonynca! There are several threads that try to discuss this and they all suggest:

*Upmixing/Processing

*All Pass Filters

*Speaker Placement

What I don’t see a lot of is clarifications on HOW. Yes it is specific to each individual car but how about if everyone shared HOW they used one of the above or any method they used to obtain an enjoyable 2 seat tune.

You call the shots tonynca its your thread! I guess I’m just proposing some sort of format to post?

Something like:
1) Method
2) Time delay position (driver, passenger, center, average?)
3) HOW you used the method to achieve the tune

**If someone knows why a certain method won’t work very well, please explain why that is the case instead of just pointing out that it doesn’t work well.**

We can all learn and experiment based on each others experiences.

Oabeieo gave us an explanation of a methodology he uses. Might not work for you but it did for him. You won’t know until you try it yourself.

Pb82 Ronin shared a methodology as well. Works well for him. Maybe others are looking for a different method for different type of result than that.

Well hey that’s why we have a thread like this. If you don’t like his way, then try a different user’s approach.

There is no exact one way to achieve this. At least not yet that I know of. However, as tonynca suggested, Please share a processes that you have tried and believe it to be successful.

Metanium shared a method as well. But I’m still curious to know where are you time aligning your woofers with the Real Center algorithm? Is everything still aligned to the driver seat?

____________________________

My current method:

I’m kinda cheating. I’m using already upmixed (5.1 DTS Neural on a 2016 Civic) signals from my stock head-unit that are passed through the high level inputs of my DSP. The staging is decent for both front seats but my tone is not the greatest for both seats. The upmixed signals are pre EQ’ed to stock speakers and already time aligned to stock locations. I can play with the headunit EQ or the EQ on my DSP but the tone of this tune is kind of always tainted.

Also the stock setup has a 2 way front stage + center. My after market setup is 3 way front stage + center with the mid-bass in stock location, tweeter in stock location, and added midrange right next to stock tweeter location.

My time alignment adjustments are minimal as I’m basically adjusting the already in place stock time alignment. Unfortunately I am not sure where the stock time alignment position is. There is also some time smearing happening because I’m summing 50% tweeter signal and 50% mid-bass signal (2 different time delays) for my midrange signal.

So this 2 seat tune method is full of compromises but it does a presentable job in my specific car.

What works for y’all?
 

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Discussion Starter #13
Speaker placement is not really an option anymore.

How do you use all pass filters for this? I heard about it but didn't get more info from Audison tech.

I'm using a Bit one HD which has all pass filtering.


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Oabeieo is pretty knowledge when it come to all pass filters so he is probably onto something with his method. I have always resorted to using upmixers, so I too would like to know specific ways/methods of manipulating All Pass filters for 2 seat tuning (even if it only worked for a specific setup).

I do remember subterFUSE mentioning that measurement software like Smaart or SysTune is usually required to be able to get All Pass Filters correct. But again HOW people are doing it in their build is the big question.
 

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How does that sound when something is hard pan right or left? Santana - black magic woman

Or Hotel California MTV live performance is a good song to check.

I was curious how good real center processing from the Helix is. Wonder if it's better than Dolby PL2 or maybe even Logic7.


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The audio that is in the center channel with the Helix upmixing is only what is present in both left and right channels originally. When something is supposed to be hard left or hard right, it still is. I’d say the Helix upmixer is quite an improvement over pro logic 2. Logic7 is too different for me to try to compare it, apples to apples. I’m extremely please from both front seats in my truck right now.

I’ve sat in Andy’s Mercedes at Knowledgefest and the AudioFrog Multiseat is the pinnacle. The Helix upmixer creates a similarly believable front stage, but lacks the width and depth Andy’s created in the AudioFrog piece w/penteo algorithm.
 

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Discussion Starter #16
The audio that is in the center channel with the Helix upmixing is only what is present in both left and right channels originally. When something is supposed to be hard left or hard right, it still is. I’d say the Helix upmixer is quite an improvement over pro logic 2. Logic7 is too different for me to try to compare it, apples to apples. I’m extremely please from both front seats in my truck right now.



I’ve sat in Andy’s Mercedes at Knowledgefest and the AudioFrog Multiseat is the pinnacle. The Helix upmixer creates a similarly believable front stage, but lacks the width and depth Andy’s created in the AudioFrog piece w/penteo algorithm.


Great feedback! Penteo is too good. I guess it's always better to have upmixing for those days with passengers and phantom image for times when you're alone.


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Coaxials would be a great starting place for a two seat tune.
 

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And here I thought the Helix upmixer for the center channel was on par with logic 7's center upmixing...this has me questioning should I stick with a used Ms-8 instead of the helix mini or mk3..hmmmm!!!

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The center position tune is my 3rd preset. It was literally as easy as time aligning for the center position. But hey...if you want to complicate the hell out of it for no reason, more power to you.

I agree with you 100% that people are over complicating it, but I also agree with:

If you only put the mic in the middle then it's tuned for the middle. Where no one will hear it.
What I’m going to try to do tomorrow, is take the *right side* PEQ settings from my driver-only preset (my logic is that opposite-side speakers have a more line-of-sight angle to the listener), which of course was based off headrest measurements, and mirror them onto the left side for my 2-seat preset. I’ll see what the frequency response is to this. Theoretically a full set of measurements from the left headrest should sound the same from the right headrest if the speakers have matching EQs and TAs (I’ll do time alignment from the center though, it needs to be symmetrical).

If this creates whacky results, my next attempt will be to take new measurements from 1 headrest of both speakers simultaneously, and EQ them the same of course, and see what the FR of that is.

If both L and R speakers have the same EQ and TA, I see no reason why you’d need to take measurements from both the driver headrest and passenger headrest and average them or whatever... just measure from 1 headrest and EQ, and it will be same for the passenger.

But yeah, I don’t think anyone wins if mic is in the center.




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If both L and R speakers have the same EQ and TA, I see no reason why you’d need to take measurements from both the driver headrest and passenger headrest and average them or whatever... just measure from 1 headrest and EQ, and it will be same for the passenger.

Unless of course, your most frequent passenger is over a foot shorter than you. Which my girlfriend is. Eh, ignoring it.




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