Sound Imaging

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Old Jul 28, 2003 | 06:32 PM
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MEAT BAG's Avatar
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Sound Imaging

People with single cabs.

What speaker locations do you think would give the best imaging/soundstage?

Im having my doors rebuilt with fiberglass with a 3-way component setup so just about anywhere on the door is possible under the handle.

I have been told that mounting the tweeter above the door switches and haveing the mid/midbass close to the factory loaction will give me a good soundstage.
 
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Old Jul 28, 2003 | 08:14 PM
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Some interesting information about kickpanel speaker placement..

taken from HERE



5.19 Why are kickpanels such a popular location for mounting speakers? [ES]

There is a lot more to mounting speakers in the kick panels than just equalizing the path length difference (PLD). Two of which are: on-axis response, and angling for pattern control. On-axis response refers to the fact that most speakers sound best when listened to on-axis, or as close to on-axis as possible. Second, after mounting your speakers in the kick panels you can then angle the speakers to take advantage of their off-axis response to use output level to overcome any PLD that is still present. The pattern control I am mentioning is one of the ways a horn loaded compression driver works very well, they not only use amplitude to overcome any PLD that is still present they minimize early reflections that can destroy imaging staging and spectral balance.

PLD can be improved more than marginally when you consider the stock locations in a lot of vehicles, or the locations most installers choose. Measure the PLD between tweeters when mounted high in the dash or at the front corner at the top of the door and you will notice its probably on the order of 24". This mounting setup requires a lot of amplitude adjustment to correct the problems induced by this difference. The nearer tweeter is out phase from the opposite side and is arriving much sooner and with much greater amplitude due to the fact is not as far away. When all these factors are added together, it is very difficult for even the most flexible DSP unit to correct. On top of that, not many people or installers have access to the necessary tools to properly set up time delays using a DSP -- TEF, MLSSA or other very expensive time domain measuring equipment are required to do the job properly.

There will always be trade offs involved and deciding which trade offs to take can be very hard. A small dropout due to phase cancellation will probably not be noticed by most people but most people will quickly notice when a vehicle is not imaging properly, and if you can move the problem to higher frequency where we determine localization more from amplitude rather than phase differences, it will be much easier to deal with. Also, if you minimize the time/phase difference it will be much easier to correct with amplitude.

Some people complain that kickpanel mounting gives a low sound stage. However, keep in mind that when any stereo system is imaging properly the point sources can no longer be localized. When our brains can no longer localize the point sources it will then hear things at eye level.
 
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Old Aug 5, 2003 | 10:29 PM
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I'd also say kicks. I used to have them and will most likely be building another pair. I would do tweeter and midrange in the kicks and midbass in the doors. Id you deaden the doors you will get a VAST improvement in midbass response! In an F-150 there is more than enough room to do kicks for 2-ways.
 
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Old Aug 6, 2003 | 02:06 AM
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Keeping the tweeter within 1 wave length(a few inches) of the midwoofer is also key for proper sound stage imaging, keep that in mind. If you want a 3 way seperate system, I suggest 6.5s, 4s, and a 1 inch tweeter. that will rock and hit all levels of mid to upper frequencies VERY well if you get good products, MB Quart and JL come to mind.
 
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Old Aug 30, 2003 | 02:35 AM
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Very good reply TEK. Well thought out well balanced acurate statement. All depth and level of imaging are exactly what you said, Psychoimaging where the brain tells the listener where it thinks the sound is coming from. The most important part for all SQ is phase shift and time alignment. You can have the cancellation effect if the PLD's cancel each other out because they are out of phase with each other.

 
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Old Aug 30, 2003 | 02:42 AM
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HEY TEK! I forgot the equipment that we found best to use and not got to far out on a limb cost wise was just your plain ol run of the mill Audio Control RTA with pink noise to figure out if we had cancellation occuring in any frequencies due to PLD and cancellation. I understand this is not quite as good as some of the more advanced time alignment test equipment available but you can achieve excellent results if you take the time and shift the phasing and crossover points on each speaker individually along with a good parametric to compensate in the deficient areas.
 
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