10" sub in 8" hole? Also, why is there a center dash speaker? (1 Viewer)

[ekolpack]

Remember your car is NOT your home theater. You sit at the extreme corners of a box/rectangle. So you are not at the center of the car. Thus, the need for center channel. If you just use right and left channel…then you need to DSP the hell out of it to balance the sound for all occupants because every occupant will be closer to one speaker set than the others...and that is a nightmare to balance out. You will need to aim your speakers correctly, esp the midrange and tweeter. And this is why a lot of the mid-range and/or tweeter of most high-end factory systems aim up into the “acoustic” windshield to bounce sound to the whole cabin. The goal is to provide balance sound for every seat in the house. You will have a hard time with just left and right channels...if you aim for the driver only to get good sounds, then passengers will suffer from lateralization and poor stage.

So, your car is NOT your recording studio nor your home. It is much harsher environment and poor seating.

From an audio engineering standpoint, there's no technical argument for a center channel speaker here. As you said, people are seated in the corners of a rectangle, meaning if you want perfect time/phase alignment for one listener, it is not physically possible for the other listeners to have perfect time/phase alignment. A center channel may improve this a bit, or even a lot, but the extent to which it does so will be the extent to which the stereo field / sound stage is compromised by what is usually a summed mono center. Some higher end DSP do a highly processed mono center, but that's a whole other can of worms and not really pertinent to the question of TA/phase. For example, in this ASCII outline, D is the driver and P is passenger, L C R are speakers.

L------C------R

--D---------P--

If C is playing L+R summed, then D's stereo field is skewed to the right and P's stereo field is skewed to the left. If the volume of L is increased to move D's field closer to the center, then P's field is skewed even further to the left.

If TA/phase tuning is done to favor D, then P will hear phase decoherence. If C is turned up to compensate for this, P will get better phase coherence, but now D will be hearing more summed mono C and less stereo, along with a stereo image skewed to the right.

There's a reason you'll never see a C channel speaker in home audiophile, a professional studio mixing or mastering environment that isn't specifically used for checking mono compatibility, or for 5.1/7.1 mixing, and this is it. You may occasionally see a "center fill" or "stage fill" in a very large FOH system. This is only done for very large point source or line array systems where the angle of projection for the mains is such that it misses people right in front of the stage. It's a coverage issue, and a necessary compromise, not for TA/phase coherence.

The point here is that in the asymmetrical environment of vehicles, you can choose some level of a decent compromise of decent SQ for all listeners, with decent TA/phase alignment and a decent stereo field - OR - you can choose perfect TA/phase alignment for one listening position, and everyone else gets whatever is left over. On the extremes, if you want perfect TA/phase for all listeners, you'd make the listening environment perfectly symmetrical by putting all speaker(s) in the center. TA/phase could be perfect, but of course the stereo image would be non-existent. On the other extreme, you could delete the C channel entirely, TA one side of the vehicle to create perfect phase AND stereo image coherence for one side/position in the vehicle, at the cost of everyone else's SQ.

There is no right or wrong answer here. There's no perfect solution, it's just a matter of preference for individual use cases. In my scenario, I'll be the only one in my vehicle 95% of the time, and even if I do have passengers, 95% of the time we'll be blabbing about something rather than listening to music, and then even if we are listening to music, most of them won't care about SQ all that much anyway. For these reasons, it makes sense for me to have my system perfectly tuned to the driver's position, at the cost of SQ for non-existent and/or non-music-listening and/or non-caring passengers. If you have a partner who is super into music, or audiophile children, then you may want to choose the compromise option and lean more heavily on a C chan.

Or you can have kinda the best of both worlds (which is something I plan to do) by having multiple presets in your DSP. If you want to give the give of perfect SA to your passenger, load up "PASSENGER.preset"....if you've got a party in the car and you want everyone to have a decent listen, load up "COMPROMISE.preset".

Okay, I think I've beat this horse to death....

</novel>

 

[Madtiger]

Yeah, ok…good luck with your setup. There is a big difference b/w car audio and mixing studio/home audio.

 

[grinchy]

From an audio engineering standpoint, there's no technical argument for a center channel speaker here. As you said, people are seated in the corners of a rectangle, meaning if you want perfect time/phase alignment for one listener, it is not physically possible for the other listeners to have perfect time/phase alignment. A center channel may improve this a bit, or even a lot, but the extent to which it does so will be the extent to which the stereo field / sound stage is compromised by what is usually a summed mono center. Some higher end DSP do a highly processed mono center, but that's a whole other can of worms and not really pertinent to the question of TA/phase. For example, in this ASCII outline, D is the driver and P is passenger, L C R are speakers.

L------C------R

--D---------P--

If C is playing L+R summed, then D's stereo field is skewed to the right and P's stereo field is skewed to the left. If the volume of L is increased to move D's field closer to the center, then P's field is skewed even further to the left.

If TA/phase tuning is done to favor D, then P will hear phase decoherence. If C is turned up to compensate for this, P will get better phase coherence, but now D will be hearing more summed mono C and less stereo, along with a stereo image skewed to the right.

There's a reason you'll never see a C channel speaker in home audiophile, a professional studio mixing or mastering environment that isn't specifically used for checking mono compatibility, or for 5.1/7.1 mixing, and this is it. You may occasionally see a "center fill" or "stage fill" in a very large FOH system. This is only done for very large point source or line array systems where the angle of projection for the mains is such that it misses people right in front of the stage. It's a coverage issue, and a necessary compromise, not for TA/phase coherence.

The point here is that in the asymmetrical environment of vehicles, you can choose some level of a decent compromise of decent SQ for all listeners, with decent TA/phase alignment and a decent stereo field - OR - you can choose perfect TA/phase alignment for one listening position, and everyone else gets whatever is left over. On the extremes, if you want perfect TA/phase for all listeners, you'd make the listening environment perfectly symmetrical by putting all speaker(s) in the center. TA/phase could be perfect, but of course the stereo image would be non-existent. On the other extreme, you could delete the C channel entirely, TA one side of the vehicle to create perfect phase AND stereo image coherence for one side/position in the vehicle, at the cost of everyone else's SQ.

There is no right or wrong answer here. There's no perfect solution, it's just a matter of preference for individual use cases. In my scenario, I'll be the only one in my vehicle 95% of the time, and even if I do have passengers, 95% of the time we'll be blabbing about something rather than listening to music, and then even if we are listening to music, most of them won't care about SQ all that much anyway. For these reasons, it makes sense for me to have my system perfectly tuned to the driver's position, at the cost of SQ for non-existent and/or non-music-listening and/or non-caring passengers. If you have a partner who is super into music, or audiophile children, then you may want to choose the compromise option and lean more heavily on a C chan.

Or you can have kinda the best of both worlds (which is something I plan to do) by having multiple presets in your DSP. If you want to give the give of perfect SA to your passenger, load up "PASSENGER.preset"....if you've got a party in the car and you want everyone to have a decent listen, load up "COMPROMISE.preset".

Okay, I think I've beat this horse to death....

</novel>

Yeah, I’ve got a preset for driver offsets, as well as the ‘general’ preset. And ‘demo’, and ‘bass cut’, I run pretty much always in demo. My dsp has only basic center summing, but I like the soundstage anyhow in the front, I feel like the center is helping.

‘Demo’ maxes out the sub down as low as it will physically go, which with room gain and nvh sounds pretty good at 60mph highway, and bass a few db hot in the driveway.

 

[ekolpack]

Yeah, ok…good luck with your setup. There is a big difference b/w car audio and mixing studio/home audio.

There's really not. Physics don't change because you're in a car. The fact that the driver is not in the center is effectively negated by proper TA. There's nothing special about the environment of a car that makes a C speaker work better than, say a home theatre or music venue where lots of listeners are all over the place.

 

[greynolds]

There's really not. Physics don't change because you're in a car. The fact that the driver is not in the center is effectively negated by proper TA. There's nothing special about the environment of a car that makes a C speaker work better than, say a home theatre or music venue where lots of listeners are all over the place.

Other than atrocious acoustics in a car (among other things, that darn windshield is a crazy reflective surface) and the fact that with a reasonably well setup home theater system, you generally won't have listeners at extreme corners of the listening space like you do in a car. Getting good sound in a car is obviously achievable, but the nature of the environment means that expecting to compete with what can be achieved at home is kind of hopeless. While I spent a pretty good chunk of money on my home theater electronics (Benchmark AHB2 amps all around) and speakers (3 pairs of Revel Ultima2 Salons + Voice), I would never spend big money on a car audio system. For me, the stock system in my LC is good enough for what it needs to do.

That isn't to say that I don't respect the effort you're putting into it or think you're a fool for doing so. I'm sure the end result will be capable of sounding pretty darn good. If it makes you happy, that's all that really matters in the end. So I'll continue following this thread because what you're doing IS interesting.

 

[ekolpack]

Yeah, I’ve got a preset for driver offsets, as well as the ‘general’ preset. And ‘demo’, and ‘bass cut’, I run pretty much always in demo. My dsp has only basic center summing, but I like the soundstage anyhow in the front, I feel like the center is helping.

‘Demo’ maxes out the sub down as low as it will physically go, which with room gain and nvh sounds pretty good at 60mph highway, and bass a few db hot in the driveway.

Other than atrocious acoustics in a car (among other things, that darn windshield is a crazy reflective surface) and the fact that with a reasonably well setup home theater system, you generally won't have listeners at extreme corners of the listening space like you do in a car. Getting good sound in a car is obviously achievable, but the nature of the environment means that expecting to compete with what can be achieved at home is kind of hopeless. While I spent a pretty good chunk of money on my home theater electronics (Benchmark AHB2 amps all around) and speakers (3 pairs of Revel Ultima2 Salons + Voice), I would never spend big money on a car audio system. For me, the stock system in my LC is good enough for what it needs to do.

That isn't to say that I don't respect the effort you're putting into it or think you're a fool for doing so. I'm sure the end result will be capable of sounding pretty darn good. If it makes you happy, that's all that really matters in the end. So I'll continue following this thread because what you're doing IS interesting.

Man, well I really don't want to get into a super technical acoustic discussion here, but all things considered, a vehicle isn't a terrible environment, acoustically speaking.

The windshield isn't ideal, but a curved, angled windshield is far better than parallel, flat windows in most rooms. The curved/oddly-shaped interior is better than the 90 degree parallel walls in most rooms. The curved corners are better than bi-axial or tri-axial corners without bass traps. The moderately padded walls are better than highly reflective (at high freq) drywall, especially when it's parallel to other surfaces.

I won't go into all the technical reasons why, but if you want to go down a rabbit hole, look up room modes, standing waves, bass build-up in corners, reflective surfaces, and room treatment.

In short, every listening environment will have it's challenges and is unique in certain ways. A vehicle is no different in this regard....and in many ways, a vehicle is better than the standard bedroom or living room or generic boxy room that many people convert into control rooms. The iso tracking rooms at my studio have oddly shaped, non-parallel, non-symmetrical walls using soundboard (semi-absorbent, somewhat broadband) low-reflection surfaces. I added a scoop on the back wall behind my main monitors in CR A and bass traps to reduce LF buildup in bi-axial and tri-axial corners. This is all somewhat analogous to what you get in a vehicle and what is lacking in many "home studios", which are acoustically atrocious. Of course we also have skyline and/or stepped diffusers, OC703 panels, RFZ listening positions, etc....but the point is, a vehicle really isn't all that bad acoustically. Will it ever sound like my control room? Obviously no....but with good drivers, good amps, good DSP properly tuned, and no C chan speaker, I bet I can get it sounding a lot better, or at least more accurate, than many people's "control rooms".

 

[pvchaitanya]

The main reason I saw for center console speaker is, for speaking navigation directions and messages.
I found it effective, when kids are listening or watching movie I can still listen to factory nav directions.

 

[Madtiger]

Have you picked out the tweeters and midrange speakers?

 

[Julian73]

From an audio engineering standpoint, there's no technical argument for a center channel speaker here. As you said, people are seated in the corners of a rectangle, meaning if you want perfect time/phase alignment for one listener, it is not physically possible for the other listeners to have perfect time/phase alignment. A center channel may improve this a bit, or even a lot, but the extent to which it does so will be the extent to which the stereo field / sound stage is compromised by what is usually a summed mono center. Some higher end DSP do a highly processed mono center, but that's a whole other can of worms and not really pertinent to the question of TA/phase. For example, in this ASCII outline, D is the driver and P is passenger, L C R are speakers.

L------C------R

--D---------P--

If C is playing L+R summed, then D's stereo field is skewed to the right and P's stereo field is skewed to the left. If the volume of L is increased to move D's field closer to the center, then P's field is skewed even further to the left.

If TA/phase tuning is done to favor D, then P will hear phase decoherence. If C is turned up to compensate for this, P will get better phase coherence, but now D will be hearing more summed mono C and less stereo, along with a stereo image skewed to the right.

There's a reason you'll never see a C channel speaker in home audiophile, a professional studio mixing or mastering environment that isn't specifically used for checking mono compatibility, or for 5.1/7.1 mixing, and this is it. You may occasionally see a "center fill" or "stage fill" in a very large FOH system. This is only done for very large point source or line array systems where the angle of projection for the mains is such that it misses people right in front of the stage. It's a coverage issue, and a necessary compromise, not for TA/phase coherence.

The point here is that in the asymmetrical environment of vehicles, you can choose some level of a decent compromise of decent SQ for all listeners, with decent TA/phase alignment and a decent stereo field - OR - you can choose perfect TA/phase alignment for one listening position, and everyone else gets whatever is left over. On the extremes, if you want perfect TA/phase for all listeners, you'd make the listening environment perfectly symmetrical by putting all speaker(s) in the center. TA/phase could be perfect, but of course the stereo image would be non-existent. On the other extreme, you could delete the C channel entirely, TA one side of the vehicle to create perfect phase AND stereo image coherence for one side/position in the vehicle, at the cost of everyone else's SQ.

There is no right or wrong answer here. There's no perfect solution, it's just a matter of preference for individual use cases. In my scenario, I'll be the only one in my vehicle 95% of the time, and even if I do have passengers, 95% of the time we'll be blabbing about something rather than listening to music, and then even if we are listening to music, most of them won't care about SQ all that much anyway. For these reasons, it makes sense for me to have my system perfectly tuned to the driver's position, at the cost of SQ for non-existent and/or non-music-listening and/or non-caring passengers. If you have a partner who is super into music, or audiophile children, then you may want to choose the compromise option and lean more heavily on a C chan.

Or you can have kinda the best of both worlds (which is something I plan to do) by having multiple presets in your DSP. If you want to give the give of perfect SA to your passenger, load up "PASSENGER.preset"....if you've got a party in the car and you want everyone to have a decent listen, load up "COMPROMISE.preset".

Okay, I think I've beat this horse to death....

</novel>

One statement, a home or studio system will be designed for sweet spot at sound center.