Car audio tech

[khail19]

Originally Posted by cody

Why bother? Rear fill is overrated.

I agree, but each to their own.

[Dean]

Originally Posted by cody

Why bother? Rear fill is overrated.

I have never understood this comment. Considering head placement in a car, I would think rear door speakers would be the primary place to put speakers for stereo separation effect which should include midrange and highs. Given the delay systems we have for home theater units, I'm surprise there isn't a big call for left channel delay on high end car audio.

And what happened to rear deck speakers? Compared to a door, what a great open volume of space for larger cone drivers if properly sealed from the passenger compartment. And the rear window makes an reasonably shaped cone reflector. The Bose systems sure take advantage of it, not that they are the best out there, but they sure have a reputation for sound engineering.

Maybe I'm just stuck in the days of large magnet efficient drivers at low-medium wattage, low THD and crisp sound, not ass thumping bass and 8 lanes of sound.

[khail19]

Originally Posted by Dean

I have never understood this comment. Considering head placement in a car, I would think rear door speakers would be the primary place to put speakers for stereo separation effect which should include midrange and highs. Given the delay systems we have for home theater units, I'm surprise there isn't a big call for left channel delay on high end car audio.

Without time alignment, having stereo sound coming from more than 2 speakers tends to pull the soundstage back towards the rear. If you have the ability to properly delay all the speakers to create the proper ambience for rear fill, then it can improve your sound. Most systems don't have this capabiility, so having a single point source for left and right channels is usually the way to go.

Most of the high end decks nowadays do have some time alignment built in (mine does), but it seems that the market for features like that has been steadily declining for the last 5-10 years.

[sperry]

Originally Posted by khail19

Without time alignment, having stereo sound coming from more than 2 speakers tends to pull the soundstage back towards the rear. If you have the ability to properly delay all the speakers to create the proper ambience for rear fill, then it can improve your sound. Most systems don't have this capabiility, so having a single point source for left and right channels is usually the way to go.

Most of the high end decks nowadays do have some time alignment built in (mine does), but it seems that the market for features like that has been steadily declining for the last 5-10 years.

Yeah who cars about car audio quality when everyone's on their cell phones all the time anyway.

[Dean]

Originally Posted by khail19

Without time alignment, having stereo sound coming from more than 2 speakers tends to pull the soundstage back towards the rear. If you have the ability to properly delay all the speakers to create the proper ambience for rear fill, then it can improve your sound. Most systems don't have this capabiility, so having a single point source for left and right channels is usually the way to go.

Most of the high end decks nowadays do have some time alignment built in (mine does), but it seems that the market for features like that has been steadily declining for the last 5-10 years.

I'm not sure I buy that reasoning. the reason it moves rearward is that there is often a whole lot more speaker in the rear and a whole lot less dashboard, seats, legs, etc absorbing it. All this effort to generate front sound through all those obstructions just doesn't make sense to me. Highs and high Mid I understand if you can get it out of the foot wells, but trying to generate mid-lows up front where there is no space and sound absorbing galore is a loosing battle IMHO.

IMHO the sound quality in an Audi A6/A8 or similar with a "stock" Bose 7-9 speaker system where > 1/2 of them are in the rear sounds much richer, cleaner and balanced than any of the front loaded after market systems I have heard.

Until they had to make room for air bags, the headrest speakers in the Miatas actually had pretty damn good sound for cheap ass factory speakers and stereo separation was great

Heck, some of the classic 6x9 rear deck 3 ways sound better than half the crap I've heard with just front stages. It goes back to where are the speakers? If the only place you can put a high or midrange speaker in the front is down next to the seat/feet/legs/floor/carpet under the dash, IMHO you are wasting your time. You need a pink noise generator and headrest microphones and automatic acoustic analysis each time the stereo turns on to be able to properly EQ the sound for accurate reproduction.

But as I said, it is as if accuracy or maybe cleanliness and richness are not important any more. It is about loud and bass, not accuracy. ( Or at least as can be expected in a tin box.)

[100_Percent_Juice]

Originally Posted by Dean

You need a pink noise generator and headrest microphones and automatic acoustic analysis each time the stereo turns on to be able to properly EQ the sound for accurate reproduction.

thats only important if your listening to Celine Dion.

Originally Posted by Dean

But as I said, it is as if accuracy or maybe cleanliness and richness are not important any more. It is about loud and bass, not accuracy. ( Or at least as can be expected in a tin box.)

Exactly. Its like drinking a fine wine with dinner. If your dinner is a big mac and fries, the wine will be waisted on a crappy meal. Striving for accurate reproduction and sound staging is an awesome goal but if your platform is in a noisy subaru, its wasted.

[cody]

I just enjoy the soundstage being in front of me, not behind me. It just sounds better to me. I didn't realize that it could be due to time alignment though...neat stuff.

[khail19]

Well for the vast majority of consumers, loud bass and loud highs are what they like to hear. To me, accurate reproduction across the frequency spectrum is important (and I don't listen to Celine Dion!). Being able to play accurately as well as getting sufficient volume is usually hard to achieve, because the car is a terrible place to listen to music. I do notice that nearly every competition vehicle I've seen has no rear fill, and the ones that do have it turned down to barely audible.

[Dean]

The only "competition" cars I have seen are for loudest, not fidelity, so I just don't know.

What do they compete based on?

With the driver and passenger in the car?

Do the windows still roll all the way down?

And across what frequency range?

I'm just wondering if competition cars have any relationship to the real world. If there are no humans with fat legs and pants in the car and just a test microphone at headrest height, I could see front stage only making flat response.

With live clothed humans, working windows and a stock dash I don't know how you get anywhere near flat response with only a front stage. It would be great, but I can't see the acoustics easily allowing it.

[khail19]

Originally Posted by Dean

The only "competition" cars I have seen are for loudest, not fidelity, so I just don't know.

What do they compete based on?

Depends on the class you compete in, but generally...
1. Proper left to right imaging and stage height (You should be able to tell where each instrument is playing from, and stage height should be dash level or higher.)
2. Seamless transitions between different speakers
3. Having the bass frequencies feel like they are coming from up front with the rest of the sound.
4. Accurate reproduction of the source material.

Originally Posted by Dean

With the driver and passenger in the car?

Usually just one judge in the driver's seat, but I've heard of some classes that use two judges.

Originally Posted by Dean

Do the windows still roll all the way down?

I'm not sure if they are required to, usually judging is done with the windows up and doors closed.

Originally Posted by Dean

And across what frequency range?

Judging is done with music, so generally most of the human hearing range. Generally that's around 20 hz up to 20,000 hz, but everyone's hearing is different.

Originally Posted by Dean

I'm just wondering if competition cars have any relationship to the real world. If there are no humans with fat legs and pants in the car and just a test microphone at headrest height, I could see front stage only making flat response.

With live clothed humans, working windows and a stock dash I don't know how you get anywhere near flat response with only a front stage. It would be great, but I can't see the acoustics easily allowing it.

No microphones are used in an SQ (Sound Quality) competition, just live judges. You're thinking of a SPL (Sound Pressure Level) competition where a mic is placed in the vehicle and the object is to get the highest decibel level possible. I don't see very many winning vehicles that have a truly flat response. Usually, the environment does not permit a flat response to be accurate to the source material. Also, the fact that the judges are human makes it very subjective, and even in the home setting a perfectly flat response isn't very pleasing to the ears.

Obviously, once you get in the car, roll down the windows and start driving, all of your musical accuracy goes out the door.

[Kevin M]

Actually it goes out the window. :rimshot:

[Dean]

Originally Posted by khail19

Depends on the class you compete in, but generally...
...
No microphones are used in an SQ (Sound Quality) competition, just live judges. Also, the fact that the judges are human makes it very subjective, and even in the home setting a perfectly flat response isn't very pleasing to the ears.

Thanks, this explains much. Humans are a terrible judge of reproduction accuracy since most people have never heard flat response much less good stereo separation. Wave form comparison with high end certified mics should be the test.

I don't agree that flat response sounds bad. I haven't done it since I changed furniture, but the pink noise calibration mode on my EQ at home lets me get reasonably close to flat response and with decent source material, that sounds very good to me.

Once I have that set, I don't mess with it much unless I substantially change listening volume or the source material is crap, and then I do gross changes with loudness, bass or treble controls, not the EQ.

Perhaps foolishly, but I assume the sound engineers doing the final mixing on an "album" do so in an acoustically accurate environment using high quality calibrated monitors. Maybe that is naive.

[khail19]

Originally Posted by Dean

Thanks, this explains much. Humans are a terrible judge of reproduction accuracy since most people have never heard flat response much less good stereo separation. Wave form comparison with high end certified mics should be the test.

I would hope the judges have better ears than the average person.

Originally Posted by Dean

Perhaps foolishly, but I assume the sound engineers doing the final mixing on an "album" do so in an acoustically accurate environment using high quality calibrated monitors. Maybe that is naive.

I think on well recorded music that is true. Unfortunately, a lot of popular rock and rap music doesn't fall into that category.

[Dean]

Originally Posted by khail19

I would hope the judges have better ears than the average person.

Not likely. humans are OK at A vs. B comparisons like eye tests, but not typically good at wave form accuracy. That is why mp3s at 128K CBR sound pretty good to most people until you put them up against the original material at which point at least some can recognize the differences.

[khail19]

Originally Posted by Dean

Not likely. humans are OK at A vs. B comparisons like eye tests, but not typically good at wave form accuracy. That is why mp3s at 128K CBR sound pretty good to most people until you put them up against the original material at which point at least some can recognize the differences.

I didn't mean better ears in a literal sense. I should have said better trained ears than the average person. Judges need to be very familiar with the recordings used during competition, and they listen to them on a reference system frequently so that they can compare to the systems they are judging.

[Dean]

Originally Posted by khail19

Oh, and someone buy my amp!

Sorry, I thought you sold everything already...

Moderators, please move the audio discussion when you get a chance.

[100_Percent_Juice]

Originally Posted by khail19

Obviously, once you get in the car, roll down the windows and start driving, all of your musical accuracy goes out the door.

This is all I was trying to say.

I like awesome sound reproduction just as much as the next fruit bat. I wasn't trying to say "hey just buy any speakers and place them anywhere because it really doesn't matter". I listen to all my music direct my ipod ever since all my cds were stolen which has been years now. There is a huge difference in sound quality. Since me car is loud, what I would normally miss out on by using mp3, is filled with exhaust and rattle.

[khail19]

Originally Posted by Dean

Sorry, I thought you sold everything already...

Moderators, please move the audio discussion when you get a chance.

No worries, at least the discussion was keeping my thread near the top. I think it is sold now, just waiting on payment from another board.

[wrxkidid]

khail do you have any 10 inch woofers you want to sell or any recomendations on a good one for around $100 i was looking at an eclipse sw4000 but im not sure. if i can find a decent sub or if you have one ill probably go for the amp.

[khail19]

Originally Posted by wrxkidid

khail do you have any 10 inch woofers you want to sell or any recomendations on a good one for around $100 i was looking at an eclipse sw4000 but im not sure. if i can find a decent sub or if you have one ill probably go for the amp.

The amp sold earlier, sorry.

Right now as far as subwoofers I have:

8" Planet Audio Neo8 4 ohm - $30

10" Elemental Designs 10kx dual 2 ohm - $60

12" Eclipse SW4200 4 ohm - $50

12" Boston RS12 4 ohm - $40

I have several sealed boxes that would fit these subs as well if you need one.

The Elemental 10kx is a really nice sub, it has a nomex flat cone that sort of looks like carbon fiber. Very nice sounding sub as well, I paid around $100 used for it when I bought it.

[Dean]

Hey, get this for sale crap out of our audio tech thread.