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View Full Version : front stage: in the roof facing down?



Kryptonitewhite
07-27-2011, 09:15 PM
I think the biggest thing that caused my van build to sink right away was my decision to place the front stage drivers in the ceiling. Right away everyone was angered and outraged that i would put such great drivers in such a terrible location. However, my point of view is that most drivers are placed in the doors...where the seat, floor, and human body block, deflect, absorb, and tamper with the sound in every way. If the drivers are down on the floor in kicks and down in the door, they are faced up to raise the sound stage. How is that different than putting them up high and facing them down? I am sure that it does make a huge difference, so if I was out strictly to compete (I don't know if I could even enter prestigious competitions...let alone place if I were allowd) I may not have. But this was not built for SQ, nor SPL. There is no EQ, no time delay, no distance punched in. No phase alignment or flat out reversing polarity on a driver or a few. No consideration given to a baffle.

Here is a picture of the closest front stage to mine as I could find, but placed in the "proper" location. 2 heavy duty tweets, 1 solid midrange, and 2 heavy duty midbasses. This guy also has 4 18's for the sub stage.

http://i248.photobucket.com/albums/gg178/kryptonitewhite/photo210.jpg

To me those drivers face up a little as to point to the ear... will they sound like they come from below? They will fire into the seat and person. When I am in my spacious van, my side, arm, and leg all touch the door. If my drivers were there, I would push against them. If they were in the Kicks, my body would block them. Above my head, they are unobstrocted and the sound appears to come from strait ahead, though slightly from above. Eye level.

I do not know if this vehicle was designed with SQ, staging, imaging, whatever in mind or not. The speakers in the pillar seem the best location...but don't they seem to come from the sides? Or does facing them strait in make them appear to sound like they are right in front of you not to the side? Like having them above facing strait down.

http://i248.photobucket.com/albums/gg178/kryptonitewhite/DSC07235.jpg

Down here they shoot strait across the top of your leg and lap to your face? Do they sound like they are coming from the road?

http://i248.photobucket.com/albums/gg178/kryptonitewhite/DSC07221.jpg

Now this is the same vehicle I have. If I had put my drivers toward the middle/bottom, the seat, floor, and I would have blocked them.

http://i248.photobucket.com/albums/gg178/kryptonitewhite/Picture298-1.jpg

http://i248.photobucket.com/albums/gg178/kryptonitewhite/Picture297.jpg

http://i248.photobucket.com/albums/gg178/kryptonitewhite/IMG_2576.jpg

http://i248.photobucket.com/albums/gg178/kryptonitewhite/IMG_2575.jpg

Kryptonitewhite
07-27-2011, 09:15 PM
If I had put them up higher, I, my body and arm, would have blocked them and pushed up against them. I always have my arm up on that shelf, windows up or down. Only open spot is the handle and switches.

http://i248.photobucket.com/albums/gg178/kryptonitewhite/CIMG6210.jpg

http://i248.photobucket.com/albums/gg178/kryptonitewhite/CIMG6209.jpg

http://i248.photobucket.com/albums/gg178/kryptonitewhite/CIMG6208.jpg

http://i248.photobucket.com/albums/gg178/kryptonitewhite/CIMG6207.jpg

KyleBechtold
07-27-2011, 09:22 PM
so is this a statement or what? the reason they are in the kicks is for the sound to produce.. them sitting above your head as close as possible its like sitting your head right next to it.. look at sq vehicles.. not one has them there... all those vehicles you posted with multiple drivers etc in the door are made to get loud not necessarily sound good.. Figure out what you want and stop posting reasons why you can't do this one or that one.. do or don't no one cares its your van

hispls
07-27-2011, 09:27 PM
Way too long/complex

My .02$ the guy in the picture is NOT doing that for SQ. That many drivers in that many locations will be a phasing/immaging nightmare. Realy SQ guys to simple 2 or 3 way and if mids and tweets aren't on plane with eachother they're carefully time/phase aligned.

Whether a speaker will play well on or off-axis (pointed directly at you or listening form an angle) depends largely on the particular driver. Some are designed to play on axis well and sound like *** off, others (most car audio specific stuff) is designed to play 30-40 degrees off.

The main reason people use kickpanels is keeping the longest pathlength between each component and your ears. Up high you wind up with a more dramatic difference between left and right pathlengths...this can be corrected with TA or course.

I'd suggest making some temporary mounting to place your components in locations you think are practical. If it sounds good it is good, if you can't make it sound good....back to the drawing board.

Moble Enclosurs
07-27-2011, 10:12 PM
That is not for SQ, its obvious. But I will tell you this: I am working on a setup in my vehicle that uses phantom resonances to get front staging effects while Im driving, and I have two TB 1" dome tweeters Im using that are located in the roof, 12" in front of my head(near the window was the best resonance location I measured for indirect reflection to the headrest), and i am not letting it hit my headrest directly as mentioned. There is gong to be a quarter circle bend to block direct wave propagation and blend with the spl output of my door speakers, and give higher sensitivity from the reflected wave from the windshield/dash combination. I have measured the resonance paths for this to be EXACT with the center of the headrest. Here is an idea of it:

http://img854.imageshack.us/img854/2/tweeterreflections.jpg (http://imageshack.us/photo/my-images/854/tweeterreflections.jpg/)

Uploaded with ImageShack.us (http://imageshack.us).

This sketch is not exact to the actual measurements I have made so far, but was put together for a basis/beginning idea. I have the tweeters and have tested them in this location with a temp deflector, and it does to what it is meant for. The two main reflection points are not exactly in the same headrest position, but this was impossible due to the shape of the dash not being completely flat, but in the picture shown, the reflections are exact form my calculations so far. SO, its not a bad idea to have them up there, as long as they are high sensitivity, good power rated, and properly configured.

Kryptonitewhite
07-27-2011, 10:25 PM
wow that looks complex! As long as youre as happy with your outcome as I am with mine!

Kryptonitewhite
07-27-2011, 10:49 PM
I am cutting down my wall right now with a sawzall, making a regular enclosure facing up port back, and mounting the front stage in the back, so that the front stage and the subs have distance to develope.

KyleBechtold
07-27-2011, 11:16 PM
I am cutting down my wall right now with a sawzall, making a regular enclosure facing up port back, and mounting the front stage in the back, so that the front stage and the subs have distance to develope.

behind your head? you will hear them coming past before they develop..

grimreper912003
07-27-2011, 11:16 PM
Arent you the same guy who "broke in" his recones by putting power to them out of the motor prior to dropping them in?

ramos
07-28-2011, 02:29 PM
That is not for SQ, its obvious. But I will tell you this: I am working on a setup in my vehicle that uses phantom resonances to get front staging effects while Im driving, and I have two TB 1" dome tweeters Im using that are located in the roof, 12" in front of my head(near the window was the best resonance location I measured for indirect reflection to the headrest), and i am not letting it hit my headrest directly as mentioned. There is gong to be a quarter circle bend to block direct wave propagation and blend with the spl output of my door speakers, and give higher sensitivity from the reflected wave from the windshield/dash combination. I have measured the resonance paths for this to be EXACT with the center of the headrest. Here is an idea of it:

http://img854.imageshack.us/img854/2/tweeterreflections.jpg (http://imageshack.us/photo/my-images/854/tweeterreflections.jpg/)

Uploaded with ImageShack.us (http://imageshack.us).

This sketch is not exact to the actual measurements I have made so far, but was put together for a basis/beginning idea. I have the tweeters and have tested them in this location with a temp deflector, and it does to what it is meant for. The two main reflection points are not exactly in the same headrest position, but this was impossible due to the shape of the dash not being completely flat, but in the picture shown, the reflections are exact form my calculations so far. SO, its not a bad idea to have them up there, as long as they are high sensitivity, good power rated, and properly configured.

Interesting concept, but how are you compensating for the impulse delays of the individual drivers? :)

Moble Enclosurs
07-28-2011, 02:45 PM
Interesting concept, but how are you compensating for the impulse delays of the individual drivers? :)

If you are referring to time decay involving impulse response, with the limitation of the vehicle construction, there really is no way to compensate for that as it will exist regardless, but an out-of-phase connection with the main drivers in the doors will hopefully help with the delay, at least at the listening position. I have a phase control on the crossover that allows me to control the time delays to a point. But with this many resonances, again, not possible to completely alleviate in a vehicle for sound reproduction.
Dampening will not help, as the resonance will be needed to create the effect. So, I am experimenting with this through the weekend to see the degree of phase these create to match them as much as possible with the timing of the main drivers.
it may be a surprise, but improper phase may be the key to correct staging in this concept. I do not know until I measure it and test it out. I want to try to keep reverb as minimal as possible, though it will have to exist for this to work. Will be interesting, and might be a failed attempt to staging, but I dont know yet.

keep_hope_alive
07-28-2011, 02:51 PM
http://www.hybrid-audio.com/Clarus_Master_Manual_Final.pdf
this manual covers the basics on sound stage creation.

you want to take PLD, ITD, and IID into consideration when choosing driver placement and crossover points. we're trying to trick our ears into creating a sound stage.

i see lots of problems in the pictures above, including a lot of phase interference and cancellation, as well as improper enclosure volumes and shared airspace.

Moble Enclosurs
07-28-2011, 02:58 PM
http://www.hybrid-audio.com/Clarus_Master_Manual_Final.pdf
this manual covers the basics on sound stage creation.

you want to take PLD, ITD, and IID into consideration when choosing driver placement and crossover points. we're trying to trick our ears into creating a sound stage.

i see lots of problems in the pictures above, including a lot of phase interference and cancellation, as well as improper enclosure volumes and shared airspace.


It would be better to see that actual vehicle he has as well, and not an "as close as possible" representation.

keep_hope_alive
07-28-2011, 03:00 PM
http://img854.imageshack.us/img854/2/tweeterreflections.jpg (http://imageshack.us/photo/my-images/854/tweeterreflections.jpg/)

i like that you're thinking about this and you're not afraid to try something different.

the thing to taken into consideration is that sound does not travel in one direction. it eminates hemispherically from the driver, then recreates everytime it hits a lip/edge (also called diffraction). each time sound waves strike a flat surface, they recreate hemispherically. in the picture above, you'll get multiple arrivals, all at different times -
1. direct from the tweeter around the shield
2. off the windshield
3. off the dash
4. off the windshield again
5. you'll also get 4-5 arrivals from the side windows since each surface up front will produce sound waves that will strike the window
...and from any undulation on the surface of the dash.

when drawing your diagram, replace the straight lines with concentric hemisperical waves

the resulting phase interference will cause harshness or shrill sound around frequencies that experience constructive and destructive interference.

a small shield will not block sound totally, it will create a barrier effect, but sound waves will still bend around it and recreate with each object. the attenuation offered by the barrier is a function of the change in pathlength and a function fo frequency.

the best possible option for tweeters is to have a direct path to the corresponding ear, and to ensure reflections are well enough off axis to be 6-10dB lower than the direct sound. in addition, the tweeter enclosure should minimize diffraction - the best i've heard was tweeter spheres. i've built them and they sound amazing.

Moble Enclosurs
07-28-2011, 03:16 PM
http://img854.imageshack.us/img854/2/tweeterreflections.jpg (http://imageshack.us/photo/my-images/854/tweeterreflections.jpg/)

i like that you're thinking about this and you're not afraid to try something different.

the thing to taken into consideration is that sound does not travel in one direction. it eminates hemispherically from the driver, then recreates everytime it hits a lip/edge (also called diffraction). each time sound waves strike a flat surface, they recreate hemispherically. in the picture above, you'll get multiple arrivals, all at different times -
1. direct from the tweeter around the shield
2. off the windshield
3. off the dash
4. off the windshield again
5. you'll also get 4-5 arrivals from the side windows since each surface up front will produce sound waves that will strike the window
...and from any undulation on the surface of the dash.

when drawing your diagram, replace the straight lines with concentric hemisperical waves

the resulting phase interference will cause harshness or shrill sound around frequencies that experience constructive and destructive interference.

a small shield will not block sound totally, it will create a barrier effect, but sound waves will still bend around it and recreate with each object. the attenuation offered by the barrier is a function of the change in pathlength and a function fo frequency.

the best possible option for tweeters is to have a direct path to the corresponding ear, and to ensure reflections are well enough off axis to be 6-10dB lower than the direct sound. in addition, the tweeter enclosure should minimize diffraction - the best i've heard was tweeter spheres. i've built them and they sound amazing.

EXACTLY! When I went to school, they used an example of this.......putting a lit candle behind a glass....you can still blow out the candle even though the glass has a perceptional destructive viewpoint.

I wish I could utilize dipole in this setup, lol. But this would also have an effect on the direct propagation as again, physical limitations and timing are my main enemies. I agree with the direct path being much more optimum as the sensitivity/efficiency will be higher, but i will have to get door speakers that have matched or even higher sensitivity for this particular placement, as it looks like the tweeter, regardless of power output, will drown the midrange anyhow from the direct wave hitting me first. The resonances will match the midrange drivers I currently have installed, which is why the direct propagation is not going to be utilized. These TB tweeters have much higher sensitivity than the current midranges, so I am calculating that this will help with the percieved loudness of both drivers matching as close as possible and with using reflections, If I can time it correctly, it should sound like everything is coming from the middle of the glass windshield.

its the omnidirectional propagation from the mentioned side windows and such that I may have a problem with, and it cannot be expressed enough how tough this will be to get correct in a non axial environment.

But, I do not want to thread jack this, and I apologize if this had already happened. So, for the OP, do you have any other questions that may help you out as well? The best thing I can tell you is do what Im doing and just go for it. As long as you understand the effects each driver will have on the response and staging, its a possibility you can control it enough for decent sound stage. I would love to know what you come up with as well for your setup, OP.

keep_hope_alive
07-28-2011, 03:17 PM
whether or not you want to compete in SQ or even want to have a sound stage - what we all want is good sound. even the best speakers can sound bad if phase interference is not controlled. we want to minimize multiple arrival times. when several drivers are in a line and playing the same content, we get comb filtering based on the spacing and distances involved. with comb filtering, each location sounds a bit different since phase interference will shift according to the varying distances involved.

as far as speakers overhead - i'd want one in each corner firing toward the middle of the vehicle floor. getting proper airspace and a solid enclosure would be equally important. a line of speakers in the overhead will suffer from multiple arrival times and there woudn't be enough of them to perform like an actual line array. that's not to say it can't sound good in some locations. there are too many variables to generalize upon, but but the math can be done to predict where phase interference will occur, then maybe crossover points can avoid some of that.

keep_hope_alive
07-28-2011, 04:15 PM
for imaging, we are concerned about PLD and ITD below 4kHz and IID above 4kHz. you can easily attenuate tweeters in level so that they blend with the midrange. the real trick is getting enough power to a midrange to attain the desired output.

Moble Enclosurs
07-28-2011, 08:41 PM
for imaging, we are concerned about PLD and ITD below 4kHz and IID above 4kHz. you can easily attenuate tweeters in level so that they blend with the midrange. the real trick is getting enough power to a midrange to attain the desired output.

I think it will help if I redid my mids for direct propagation, such as kick panels. I want ITD as close to 0 as possible. I just want to be able to localize the signal from the reflection as mentioned for now, but in order to do that completely, I may need to rearrange the mids just for that. Then can configure the postitioning more precisely (azimuth) for the tweeters before I figure the correct propagations in relation to the mids. The problem now, is that each reflection will have its own variables that will affect the other reflections, such as the mentioned side window reflection to the listening position, but if you consider a parabolic type effect of the directivity, i believe this is highly possible to obtain control of the natural reproduction. If I can direct the reflections to a single point on the dash(as close as possible) each one will arrive (as close as possible) to the averaged listening point more so than worrying about scattered reflections. There will be of course differences in the paths still, but more controlled and considering I sit 5 different ways in my seat, I think this is plausible. But coming from a dome tweeter with half space resonance from 1 inch diameter, the waves should be somewhat close if the diffuser is close to the dome.
Just some thoughts for now.

The_Grimy_One
07-28-2011, 08:50 PM
Keep_Hope_Alive drops knowledge... Just saying.

keep_hope_alive
07-29-2011, 04:26 PM
:).

Thanks. I like sharing knowledge. And this stuff is what I'm most interested in.