home audio compared to car audio technology?

[shokhead]

bah... i like tech articles too, but generally, i think everything should be put in laymen's terms. All that to explain how much a cars interior sucks for audio... i don't think anyone could argue with that. You could just simply say you're constrained by space, seat position, and just overall environment of the car. There... let that be the cliff notes to us all!!!

BTW - after enjoying a wonderful st patties day night... i came to this conclusion. Audio is like masturbating. You keep developing and setting up more realistic ways to experience sex, but in the end.. you can never beat the real thing.

That might not sound right tommorow, so for now... mind you i've been drinking...

If you cant beat the real thing,what in the heck are you beating? LOL

 

[shokhead]

You must not be an engineer shokhead. I love technical documents. They make my day.

Nope,i clean toilets.

 

[WmAx]

IF you wanted to simulate a concert hall in car, step one would be to get a 5.1 recording made in a proper way (rear ambience only in the rear channels thank you!

But that leaves you pretty much fully in the grip of the recording engineer´s vision. And I sense that is not what you wanted?

Not really. A very good stereo encoding is usually sufficient, if you use a decoder to simulate/extract ambience, and then send it to the rear channels(assuming they are diffused sufficiently). Remember, in order to realisticly simulate ambience, you will not normally hear the rear channels/information discretely, except in cases of a quick transgression from loud to quiet occurs, then the delayed reflected signal would become obvious for a brief moment. Primarily, the rear ambience is nothing more then a slightly filtered, greatly attenuated, reflection filled, channel mixed, delayed version of the front acoustic information. Obviously, environmental(birds, A/C?) or other discrete sounds(people coughing) could not be reproduced by this method; only the spatial effect of the environment(I prefer NO audience sitting around me).

Also I would like to learn more on what the size of the dash has to do with imageing?

//ER

The size of the dash, in itelf, is irrelevant. But in my context, I was qualifying the requirement for a large dash to employ some of my ideas that would most probably work to create a realistic diffuse field. Example: a sound projector(s)/directive radiating panels mounted on the dash(requires some real estate) for example, focusing a tight sound beam that bounces off the left window and directly radiates to the right ear to intersect with the head target area of the driver. This could be repeated for the passenger seat. A discrete center channel could even be manged for each listener using this method. However, the use of soundprojectors is not conventional in car use due to size(for an acoustically operating unit) or due to limitations of technology availability(ultrasonic projecting panels).

-Chris

 

[Errin@PG]

If by this, you mean they are equal in standpoint of acoustics, then it would appear you skipped over or ignored some posts, particularly ones from me. If you don't mean this, please accept my pre-emptive apology for misunderstanding your statement.

-Chris

I typically overgeneralize/oversimplify, my apologies, when you have to explain something to the general public day in day out being in reatil you do not have the time to teach them everything involved so it has become habit and since most people that I choose to spend time around get lost when I go into detail I just simplify. You may notice. I have actually forgotten alot of the actual "terms" but I understand the logic and can explain it an easily understood manner.

So in response: The original topic was technology, but as for acoustics the home environment and the car environment have speakers specifically designed for each, since each will have a different response and as long as you have a quality amp to begin with the amp itself is not really a factor. Then location and reflection come into play: the home speakers 90% of the time are bought in a prebuilt enclosure that is then wired into the system, the car speakers need to be mounted angled etc... and yes you have more of a challenge to get proper response and accuracy if you do not understand what you are doing it becomes impossible to get it right this is where car systems fall short. Acoustic engineers build the home enclosures and typically youth's are installing car audio that have in most cases a general knowledge of what they're doing. Do you see a disadvantage here? If you were to compare an extremely good sounding home system to an extremely good sounding car system, not one done by a big box retailer or factory installed, I'm talking a year in the making SQ car. You would most likely find very few discrepencies because if they are both done right they are both going to provide an accurate sound, yes you will still have some reflections but all listening environments do to some extent.

My argument still stands that car audio is more advanced Technologically and there is more involment needed to make it sound proper in the end, but it is possible (given some insignificant variences) to get an accurate reproduction of a live concert. Keep in mind I am not saying one sounds better than the other just that the technology is more advanced in terms for car audio because of the given restrictions and limitations, you do not have these limits in home and remeber my intial statement did brush on the fact of "in scale" representation.

 

[shokhead]

I thought the car audio just did whatever home A/V did first?

 

[WmAx]

So in response: The original topic was technology,

I was specifically responding to a tangent of this, involving only the acoustics.

If you were to compare an extremely good sounding home system to an extremely good sounding car system, not one done by a big box retailer or factory installed, I'm talking a year in the making SQ car. You would most likely find very few discrepencies because if they are both done right they are both going to provide an accurate sound,

Home environment can easily facilitate diffuse sound in the points required to percieve realistic space and directions. The car, except in non-conventional, un-practical ways(at least one of which i have detailed already), does not facilitate the requirements for diffuse sound field, especially in the L side, as I have already detailed in past posts. Please address those, and how you will achieve the sufficient properties with conventional methods used in SQ installations. I am certainly open minded; but no one has explained or demonstrated how to compensate with a conventional install yet.

My argument still stands that car audio is more advanced Technologically

I have no opinions on overall technology 'advancement'. I'm only concerned with the acoustical aspect(s).

-Chris

 

[cmusic]

Acoustic engineers build the home enclosures and typically youth's are installing car audio that have in most cases a general knowledge of what they're doing. Do you see a disadvantage here? If you were to compare an extremely good sounding home system to an extremely good sounding car system, not one done by a big box retailer or factory installed, I'm talking a year in the making SQ car. You would most likely find very few discrepencies because if they are both done right they are both going to provide an accurate sound, yes you will still have some reflections but all listening environments do to some extent.

My argument still stands that car audio is more advanced Technologically and there is more involment needed to make it sound proper in the end, but it is possible (given some insignificant variences) to get an accurate reproduction of a live concert. Keep in mind I am not saying one sounds better than the other just that the technology is more advanced in terms for car audio because of the given restrictions and limitations, you do not have these limits in home and remeber my intial statement did brush on the fact of "in scale" representation.

I completely agree with the above statement.

Chris,

I am not questioning you knowlege of acoustics, but there are somethings that can be and can't be transfered from home audio to car audio. I've been in car audio for 14 years. I've helped build, tuned, listened to, and judged some of the top car audio systems in the past 10-15 years. Most of the time I can look at a system and tell how it is going to sound. Sometimes I am amazed at how good some systems sound given their odd installation. Many times I have heard car audio systems costing near $100,000 that simply sounded awfull, and in turn heard systems costing only a few hundred dollars sound wonderfull. I've heard many a system that the soundstage was much bigger than the vehicle. I've heard many systems that the tonality was so perfect I could close my eyes and think I was listening to the musical performance live.

As in home audio, there is no perfect car audio system. Most systems are outstanding in some areas and imperfect in other areas. One thing is for certain in car audio, there are no absolute scientific methods in getting "perfect" sound in a vehicle. (Since we all hear slightly differently there is no real "across the board" perfect for everyone.) There are just too many different vehicles on the road to say this one method works all the time. Like in home audio there are some techniques that I have learned over the years that work most of the time. But then when I hear a system that uses techniques I would have never used and it sounds great, I have to learn from that experience and move on.

For myself I am just getting into mid to high end home audio and home theater. I have learned some accoustics from my experience in car audio. I have also learned about proper speaker design and tuning. I am not saying I know everything but I do have some experience that I can bring to home audio.

Again Chris I mean no disrespect to you but unless you have experience in car audio you might want to attend a national level car audio show to to listen to some of the best systems before you make any more assumptions. Take what you know about home audio and be open about how some of the same knowlege may or may not be used in car audio.

 

[Errin@PG]

but no one has explained or demonstrated how to compensate with a conventional install yet.

When you talk SQ in car nothing is convetional, look at the old school days one speaker centered in dash, that was the closest a manufaturer ever got until recent developments. They then went to 2 speakers in the rear and you now need to educate people that this is not good sound because they have been conditioned to this they don't know any better. So when you talk convetional do you mean that the vehicle is still functional? Because a sub alone is unconventional by terms so where is your standpoint actually at. A home theater is unconvetional as well in terms realistically stereo sound is unconvetional. In the goal for an accurate reproduction you would truly want a shpere that radiated sound in all directions with a flat linear response from 15-30khz just so you get everything including freak harmonics in the sound spectrum.

 

[WmAx]

I've heard many a system that the soundstage was much bigger than the vehicle.

I have no doubt, you have. But this is a far cry from reproducing a realistic diffuse soundfield. Any specific ponts of acoustic radiation, that contain a sufficient reverb, will create a percieved depth. The point is how do you get past the problems to create a diffuse L field for the extreme side? You should address this, as in my former posts.

I've heard many systems that the tonality was so perfect I could close my eyes and think I was listening to the musical performance live.

I have headphones that can do the same, tonally, as you specify. But this is not creating a proper diffuse sound field to emulate the acoustic venues/spaces in the front and side planes correctly.

(Since we all hear slightly differently there is no real "across the board" perfect for everyone.)

Human hearing works on fixed principles, that are repeatable for every person. The rules of diffuse sound perception requirements, for example, are found to be very consistant from person to person. The same number of points/sources score consistantly, in quality, in scientific perceptual testing.

Again Chris I mean no disrespect to you but unless you have experience in car audio you might want to attend a national level car audio show to to listen to some of the best systems before you make any more assumptions.

It's simple. The rules of requirement for human hearing does not differ because one is in a car or in a home environment. Please explain how to create a diffuse and symmetrical soundfield for the front and side planes, in respect to the issues I have already brought up and that have yet to be addressed by anyone. So, for you to garner my acceptance of your claim is simple: provide me with the details on how to achieve a symmetrical diffuse sound field in a car SQ install using conventional transducers/technologies used typically in car SQ competition.

If you are able to demonstrate such a design, what is your estimate of this being used, and the complexity of incorporating it? If this is a RARE thing in the field, requing great complexity and unusual methodology, then I remain validated in my intial and standing statements that a car is much poorer environment acoustically compared to home environment. I proposed at least one method that should in theory be very effective at producing the requirments for a symmetrical diffuse sound field for human hearing within a car. So, I am not and have not stated it is IMPOSSIBLE.

-Chris

 

[WmAx]

When you talk SQ in car nothing is convetional,

By conventional, I mean the standard drivers and methods employed in that subject field(SQ competition).

A home theater is unconvetional as well in terms realistically stereo sound is unconvetional. In the goal for an accurate reproduction you would truly want a shpere that radiated sound in all directions

Actually, for accuracy, this would be UNDESIRABLE. However, a spheroidal dispersion can create colorazation that sounds realistic, by rules of diffuse sound field and the way it is sensed. So, while it could sound realistic on ambient material, it would not be an accurat representation of the recording due to the reflection delays, effectively impregating the room signature on the signal. With signals that contain little to no delays/reverbs, the room signature would become obvious, unless the room was heavily dampened/diffused to prevent the reflections becoming very audible, in which case it would make no sense to have the spheroidal dispersion in the first place.

with a flat linear response from 15-30khz just so you get everything including freak harmonics in the sound spectrum.

Bandwidth beyond 20Khz is not required for human hearing. It is irrelevant if harmonics are beyond 20kHz(actually, I am not aware of research that has shown beyond 16kHz to be useful for music reproduction), as they can not be discretely heard.

-Chris

 

[cmusic]

Chris,

Are you talking about having a soundstage with the listener sitting dead center and the left and right sides of the soundstage the same equal distance from the center, as it is in most home audio systems? And then recreate the same dead center listening position for both front seat passengers? Is this what you are trying to figure out?

If so I can explain that.

High-end car audio doesn’t expect each listener to have their own independent and perfectly symmetrical soundstage. We listen to and judge the soundstage as how it relates to the vehicle, not to where the listener is seated.

First, unless you drive a McLaren F1, there is no commercially made vehicle with the seats centered. There have been several competition vehicles that have re-mounted their seats closer together in the center of the car, but these vehicles were show only, and never road driven. Therefore the listeners are always going to be off to one side of center.

The ultimate goal is to have one soundstage for both listeners. When I judge I close my eyes and listen for sounds that I know are on the far edges of the soundstage. Sometimes the left and right sounds line up with the vehicle’s A-pillar, sometimes inward of the a-pillars, and sometimes outside of the a-pillars. This sets the left and right boundaries of the soundstage. Then I listen (with my eyes closed) to other sounds that I know are centered in the soundstage. Then I listen for other sounds I that know their position is in the soundstage. If everything I hear is in the correct location on the soundstage, then it should score high points. If the other judge in the other seat hears the same soundstage information I do in the same place then the system will score max (or close to max) points for soundstage and imaging. A system like this will generally put the soundstage out on the hood of the vehicle, be as wide or slightly wider than the vehicle’s A-pillars, and the center of the soundstage in the center of the vehicle.

There are systems that create one soundstage for one listener and basically screws the other listener, but those are rare and are mostly found in competition classes that have only one judge. These systems usually skew the soundstage to the left so that the center is in front of the driver.

Does this make more sense to you now?

 

[Errin@PG]

By conventional, I mean the standard drivers and methods employed in that subject field(SQ competition).

What is convetional about giving up an entire room to place one chair in the middle? All the high end SQ cars are still useable by rules and restrictions no matter the modifcations is your room with one chair still useable?

Actually, for accuracy, this would be UNDESIRABLE.

If you think about it a sphere is truely the only true reproduction. where is the sound coming from in an opera hall, yes it is focused forward but is completely dependant on the inherent reflections. So a shpere which would naturally create these reflections would be superior with the exception on any recorded reflections involved.

Bandwidth beyond 20Khz is not required for human hearing. It is irrelevant if harmonics are beyond 20kHz(actually, I am not aware of research that has shown beyond 16kHz to be useful for music reproduction), as they can not be discretely heard.

-Chris

You are not going to hear the sounds themselves, but there are anomalies withtin the way the frequencies interact within that range that will be audible if you are truly worried about a truely accurate reprodution. This get back into your vector properties as dicussed earlier.

 

[WmAx]

Are you talking about having a soundstage with the listener sitting dead center and the left and right sides of the soundstage the same equal distance from the center, as it is in most home audio systems? And then recreate the same dead center listening position for both front seat passengers? Is this what you are trying to figure out?

That is part of it, but it is only part of it, you must understand how and what the human hearing system interprets as a diffuse sound field, and why that’s important to realistic sound reproduction.

When I judge I close my eyes and listen for sounds that I know are on the far edges of the soundstage. Sometimes the left and right sounds line up with the vehicle’s A-pillar, sometimes inward of the a-pillars, and sometimes outside of the a-pillars. This sets the left and right boundaries of the soundstage. Then I listen (with my eyes closed) to other sounds that I know are centered in the soundstage. Then I listen for other sounds I that know their position is in the soundstage. If everything I hear is in the correct location on the soundstage, then it should score high points. If the other judge in the other seat hears the same soundstage information I do in the same place then the system will score max (or close to max) points for soundstage and imaging. A system like this will generally put the soundstage out on the hood of the vehicle, be as wide or slightly wider than the vehicle’s A-pillars, and the center of the soundstage in the center of the vehicle.

Thank you for the clarification. This is exactly the effect I suspected must exist in the majority of such SQ systems.

A realistic reproduction would encompass creating a virtual acoustic space, just like what you would hear in a concert hall for example. You would perceive the orchestra and instruments 40 or 50 feet in front you, and the subtle wall reflections and echoes from sides the same distance by 60 feet, etc. as well as the proper tonality and detail. I actually have been thinking about this during this conversation, and if you want to PM me with the message function of the forum, and if you are interested in how to possibly achieve an extremely realistic acoustic experience that creates a good diffuse sound field, and equally virtual for both driver and passenger, message me(note that the idea involves large dash modification(possibly entire custom dash) and some visible devices protruding from the dash.).

Does this make more sense to you now?

Yes, thank you.

-Chris

 

[guess88]

if you are interested in how to possibly achieve an extremely realistic acoustic experience that creates a good diffuse sound field, and equally virtual for both driver and passenger, message me(note that the idea involves large dash modification(possibly entire custom dash) and some visible devices protruding from the dash.

after you all discuss it, mention your results on here, cause from what i'm reading it sounds like it's already been done one many cars. I might have the wrong impression of your ideas though, but the conclusion could be intriguing.

 

[WmAx]

What is conventional about giving up an entire room to place one chair in the middle?

You don't have to. You just need a somewhat symmetrical placement. Achievable in many rooms.

All the high end SQ cars are still useable by rules and restrictions no matter the modifications is your room with one chair still useable?

Huh? I think you've forgotten the issues of disagreement, based on this seemingly out of nowhere statement/question.

If you think about it a sphere is truely the only true reproduction. where is the sound coming from in an opera hall, yes it is focused forward but is completely dependant on the inherent reflections. So a shpere which would naturally create these reflections would be superior with the exception on any recorded reflections involved.

You seem to be correlating improperly. The human senses don't care about actual replication, they care about a facsimile that has stimulated the various perceptive systems in a sufficient way so that they 'seem' real, i.e.; fool the human sensory system. Here is the simplest example that I believe most people have at least experienced: a center image from a stereo speaker pair. Is there really a sound source from the center? No. But that is the way the human hearing system operates.

I already explained how a spherical sound source will create colorations, which are audible. Do you choose to ignore this? It can produce a realistic effect, but that is different from accuracy. IN order to create an ACCURATE diffuse field, you may use direct radiating monopole devices so long as the encompass a sufficient number of surround points, in the appropriate arrangement(s).This will be very accurate in all respects according to what is encoded on the source material. It is not my opinion, nor conjecture. It is a conclusion based upon scientifically methodological perceptual [1]testing.

You are not going to hear the sounds themselves, but there are anomalies within the way the frequencies interact within that range that will be audible if you are truly worried about a truely accurate reprodution.

If you are recording a signal, or downsampling a signal that has been recorded to a 20kHz band, the intermodulated interference products from the original event will be recorded and preserved. You only hear what is within the audible band. If such interference happened in the first place to be created within the audible band, it will be recorded. If you produce additional artifacts during playback, those are not accurate, but are instead new distortions.

-Chris

[1]The Minimum Number of Loudspeakers and its Arrangement for Reproducing the Spatial Impression of Diffuse Sound Field
Hiyama, Komyiyama, Kimio
AES Preprint: 5696

 

[Buckeyefan 1]

This thread is cracking me up. You guys all know way too much about audio. The argument will never end. Does anyone get Stereophile mag? How many times can they use "nuance" in a sentence? And most of us realize there are guys dropping two to three times more in their car audio systems than they paid for their car. No way are you going to win an argument over which is better - car or home audio. And how about the nut cases that have their tube amplifier set inbetween their two 7 foot tall electrostats in a room all by themselves with one chair? Do you really want to associate with them? They can give a rats asss about HT. No way will you win that debate over car audio. I love technology. Love HT and all the new DVD's with DTS ES Discrete 6.1 encoding. Love the Class D car amps and the dual vc's (I'm running a half ohm on two 12" subs at 14.4 volts) - my neighbors love me. Keep the technology coming, and I'll keep putting the dollars out. Everyone is a winner as long as we keep mfg's to keep getting better and better.

 

[Robsarve]

A realistic reproduction would encompass creating a virtual acoustic space, just like what you would hear in a concert hall for example. You would perceive the orchestra and instruments 40 or 50 feet in front you, and the subtle wall reflections and echoes from sides the same distance by 60 feet, etc. as well as the proper tonality and detail.

I´ve heard quite a few seriously high end (home) systems. The number of them that manages to pull this off? 0. Tonal accruacy and detail is seldom a problem with the right equipment and careful use of room acoustic control, but to claim a 50 ft stage depth is.

I have about 5 meters subjective stage depth in my home setup, which quite honestly is good enough for me since i almost never listen to classical, opera or large scale jazzbands.

Stepping into the car, good stage depth is a serious problem to accive. 99.9% off all systems I´ve heard has been unable to extend their stage on the far side of the windshield. We are currently building a car that will address this, but it will involve a massive rebuild, entirely new interior, custom dash and driving/listening position relocated about 3 ft.

I actually have been thinking about this during this conversation, and if you want to PM me with the message function of the forum, and if you are interested in how to possibly achieve an extremely realistic acoustic experience that creates a good diffuse sound field, and equally virtual for both driver and passenger, message me(note that the idea involves large dash modification(possibly entire custom dash) and some visible devices protruding from the dash.).
-Chris

Why not post your ideas here, we´ve got the skill and madness enough to test it IRL!

 

[WmAx]

I´ve heard quite a few seriously high end (home) systems. The number of them that manages to pull this off?

I was talking about relative issues for most of this discussion, and why the car interior is at a huge disadvantage. But in reference to home diffuse field, it is possible to achieve the very deep soundfield without too much effort. After tonality is correctly tuned, then you must address the requirements to produce an effective diffuse field, as far as perception is concerned. You can achieve this most easily using omnipolar radiation pattern speakers, with no absorbing/diffusion of the 1st reflections off of the rear wall or side walls that surround the speakers. The area must be symmetrical in placement, and relative to the listening position. The distance from walls should be such that the direct vs. reflecting signal is a minimum of >5ms when measured at the listening position. You should not exceed this time by much unless you have a line source vertical radiation characteristic, or the reflected sound will decrease in amplitude by too great a magnitude, and gradually lose it's ability to provide the phantom sources to fool the hearing. There should also be no dampening/diffusion extending from the speaker position to the seating position along the side walls that would interfere with the 1st reflections. With a very high quality speaker(few resonances, full range, etc.), and tuned to the correct tonality, reproduction of operah, classical, etc. with the right recordings can sound extraordinarly realistic in all criteria. Adding 2 rear channel diffuse channels consisting of delayed, low amplitude mix can increase the realism by a small amount. The negative aspect of an omnipolar-type radiation speaker is reduced sound quality when playing back recordings that have little or no reverb or ambience in them. Under this condition, the room signature will become apparent(to a skilled listener).

Why not post your ideas here, we´ve got the skill and madness enough to test it IRL!

My ideas for car audio are rough and not suitable for discussion in open at this point. But I will discuss it in email or PMs if you desire.

-Chris

 

[truesounds]

the limits is what makes more advanced

Home Audio, by far. The medium simply allows for the most advanced technology to be used. Car audio has too many limitations to be the most advanced. 12V DC Power is the only kind of voltage available. There are never any allowances for driver enclosure, so you get all kinds of bad reflections and such. I could go on and on. That said, there IS some good car audio, but it's still nothing compared to the home realm.

to do what it does car audio take more advancements because car audio is working in limits it takes more to develope not trying to in rage any one but there lot of pro's and cons to both home audio price's tend to be higher and media changes to fast so more prone to up grade moe in home i know 3 times in 6 years car audio takes more work installing and is limited by size of car so more tech to build for hi's mids and subs they all need to be more verstile and most time higher build quality but home audio also has some advances over car like prossers surround sound is better than car for most part i have guess went back wards i started in home audio and have now been car mostly for 8 years now but i like tha challange of car audio thanks love both

 

[truesounds]

i agree that that car audio can sound better and not somuch about the money but about if know what are doing with what you buy i have built sq and spl on shoe string buget time is the biggest thing when on lowwer income thanks do not mean to ofend any one