2 Seat Tunes

[blockrocker]

I was curious if anybody tunes their systems for optimal 2-seat listening? I had an interesting chat with JimmyDee this morning about Andy @ Audiofrog having a 16 channel amp/dsp combo that supposedly sounds incredible and identical from either front seat. I've also seen Skizer's video with Natan Budiono and his 2 seat Suzuki. Both of these setup are highly intriguing, but it seems both use high tech products, not yet brought to market. Has anyone ever tried a similar setup with publicly available gear? What were the results?

I understand that a center channel is essential. Also, that its ultimately a compromise on optimal sound for the sake of the passenger. However, there is clearly some technology in existence that makes "competition" level SQ in each seat, no? Are these products just a matter of time - or truly one off wonders? How close is something like the DSP Ultra from being able to deliver that kind of setup?

Just curious....for something to learn about.

[Midway]

Why not do both a driver optimized and a two-seat optimized tune? That is what I am considering using the new Helix Ultra DSP and a URC.3 to toggle between the tunes.

Is this a realistic option?

One thought I also had if using the center channel tuning capabilities of the new ultra, is it important the center channel have the same components as the FR/FL stage? If tuning the center channel is similar to rear fill it may not be necessary. I ask because matching speakers is always highly recommended when adding a center channel for home theater. That is assuming the front stage components fit in the front dash.

[jrwalte]

If using a modern DSP with PEQ, matching speakers is not necessary. You can 'adjust' the sound signature of any brand. Maybe that is a rule of thumb in home theater because most don't have a high end DSP so they want to keep sound signatures similar.

[Jdunk54nl]

Two seats is where having a true center channel comes into play.
You need all of the common stuff from the left and right side to go only to the center channel.
Then you need all of that common stuff to be deleted out of the left channel and right channel so left plays just left and right plays just right.

Then as you, or anyone seat in the car, listens. The center will always be the center channel, the right will always be right, and the left will always be left for whatever position you are sitting in.

We do a lot of EQ work and T/A work so our center stage is strong but still have a left and right stage. Left side too high in certain frequencies and the stage pulls left, same if right is too high.
With the above true center, while EQ work is still needed to match the speakers, the center information can't be pulled left/right as it is in the center speaker only.

The part about getting the common and deleting the common information is the very hard part. It takes a really good algorithm and a huge amount of computing power to get it done and route it efficiently. With movies, the center channel information is already in the audio track so you do not need to analyze that and figure out what is and isn't there.


If you do not have a dedicated center channel, then it will always be a compromise and not ideal for anyone.

[blockrocker]

Very, very fascinating stuff Jdunk. How would you go about deleting common stuff from each speaker? Is everything done with an algorithm or can some of it be accomplished with standard tuning techniques? Also, can these algorithms be applied externally to a dsp or does it need to be hardwired in from the get-go? (thus one-off item that started me on this question) Finally, how many guys compete in this area of SQ? I honestly didn't know it was possible until I saw Natan's Suzuki.

Thanks for the input.

[Jdunk54nl]

Deleting the common stuff is easy. That is just left minus right/right minus left. We can do that now, it's how we get rear fill.

[blockrocker]

Deleting the common stuff is easy. That is just left minus right/right minus left. We can do that now, it's how we get rear fill.

Boy, I still have a lot to learn.
I hope to sit in a vehicle with a 2 seat tune some time soon. Seems like a cool concept, if done properly.

[BigAl205]

In the olden days of car audio, competitors had to put the speakers as far away as possible to combat ITD. With modern processors, you can just delay speakers to have the sound arrive at one point simultaneously. Having them arrive at two points simultaneously is impossible without each seat having its own individual left and right channels. Center channel is a decent compromise because most of the sound is coming from a central point on the dash, but getting it to sound right requires specialized processing.

[chithead]

So what exactly would be the requirements for it to qualify as a 2-seat listening environment? Do you sit in one seat, and have everything perceived to be directly in front, with a narrow stage, and same in the other seat? Should there be as wide a stage as possible for both seats? Or, is it supposed to sound like you just moved over one seat?

I could see the narrow stage thing being an issue (used to hear this style of tuning a few years ago at the local meets, didn't quite understand where it come from?) - but the wide of stage as possible, that could be doable. Then indeed, maybe it would sound like you just moved one seat over. Perhaps aiming, putting the speakers as far away as possible, and of course tuning would play into this, but would a center channel be absolutely necessary? And if so, what would determine that?

If you are running just a tweeter and woofer left and right, does that mean you definitely need a center that could bring more midrange into the equation? If you have tweeter, mid, woofer on left/right - would that help you get away with not needing a center, or would THAT setup be the one that definitely needs a center channel? What if you just moved the mids closer to center, keeping the tweeters as wide as possible, then of course putting the woofers wherever they can fit at. Would that help with a 2-seatlistening position install? Or would moving the mids closer create that narrow stage that requires more T/A to fix, and ruin it for one seat or the other?

[Jdunk54nl]

My classification for two seat is that center, right, and left from both seats is same spot for all seats. Sure driver will have left closer and passenger will have right so there are still some compromises on volume, eq, phase, etc. But if you asked where the center was both would point to the same spot. Same with left and right.

I've heard some that tuned to the arm rest in the center and even tried it myself. It didn't sound good from either seat and center, left, and right did not sound like they were in the same spot from either seat.

Then I sat in Andy's car a couple years ago and sat in the drivers, passenger, and rear seats and it was mesmerizing how no matter the seat, center was the same, left was the same, right was the same.

The problem with not having a center is that then you will need to t/a to something or nothing. That is where the compromise comes in, unless you can somehow get all speakers equidistant from all seats.

With a real center and real right/left, it gets easier because the left and right will never play anything in common with each other. I am not sure how you would t/a that or where to. I'd assume eq still for the driver, but that stuff is getting beyond my level of understanding.