Re: Tendean17’s - Nissan Grand Livina 2007 with 17 speakers
Some Weapons and Bullets.
My notes for driver location and something relevant from peoples that much more experience and knowledge than me .. they help me so much for my next installation :
“Primary width cues are in the midrange. Primary stage width will be dictated by placement of whichever drivers are responsible for midrange frequencies. Ambient width can be augmented with treble placement. I've heard this called 'stage boundary' width …” Highly.
“… So YES, IMO the goal is always to get the speakers as far away and as wide as possible and away from as many direct reflecting surfaces as possible … Use all the TA you want, you will not increase width…” Mic10is.
“At a minimum-keep all drivers especially mid and tweet on the same vertical plane. moving them off that same plane will cause some imaging issues, especially in the depth department. So having something like a Mid in a kick panel and then doing tweet in a Sail or door panel can cause some serious issues bc the tweet is just too physically close to the listener-no amount of TA will compensate for it.” Mic10is.
“Depth is one of THE most confused and misused terminology in car audio and in many instances its often one of the most misjudged areas in competition. Depth is the distance from the front of the stage to the rear of the stage. It is NOT how far away the stage is in relation to the listener .. I would not separate speakers if its avoidable. Multiple locations leads to multiple problems especially above 200hz or so. Depth in home audio refers to the ability to hear beyond the speaker location and not hearing the speakers.” Mic10is.
“I wouldn't worry about depth when discussing tweeters. To me, that's one of the easiest things to line up given it's driven primarily by levels. Especially when crossing higher. I'm not saying phase doesn't matter, but it's less important than the location of a midrange given wavelength. Once you get your tune right, a lot of the stage aspects of the audio system will fall in to place. You just have to focus on getting your left side and right side response to match up.” Bikinpunk.
“… Simply stick the speakers in a corner. The way that this works is that the car itself acts like a waveguide. We're not getting away from destructive interference, we're just sticking the speakers so far in a corner, the effect is less audible…” Patrick Bateman.
“… with the speakers very very close to the corners it 'pushes up' the frequency where comb filtering will begin. Once you figure out that frequency, you'd have to make a choice and either live with the comb filtering that will occur above that frequency, or filter it out and reduce the bandwidth of the driver …” Patrick Bateman.
“… On the other hand, listening off axis *does* reduce the audibility of that 3rd harmonic distortion, because it attenuates the driver mechanically not electronically … This is why low distortion speakers sound so much better.
” Patrick Bateman.
“… Midbass is not very critical for stage width or height, but is essential for depth. Also, if the path length difference is too large, say over 6 inches for the midbass range from 100 to 400 Hz, the imaging will be shifted to the close side …” Mark Eldridge.
“… Tweeters mounted only in the pillars... I'd put them next to the mids, maybe mounted just above, or in front of them, or where ever you get the best staging properties. Mounting them so far away from the mid up in the pillar can cause problems with creating a coherent wave front, and possibly comb filtering. The results can be phase related problems causing depth, height, and imaging problems … ” Mark Eldridge.
“… Based on real world physics of sound. If your tweeters are not arriving at the same time your mids are you will have comb filtering through the crossover region and your soundstage will not be correct … ” Gary Summers.
“... If you are able to build a system in your car where all the speaker drivers output arrive at the listener's ear at the same exact time, then you don't need TA …” Gary Summers.
“… These are the main reasons why "aiming" tweets in car may very well lead to surprising (or at least, non-obvious) results. It may be that aiming somewhat centrally to minimize reflective intensity ... in other words, aiming so that the PHANTOMS are as OFF-AXIS as possible ... may ALSO result in acceptable attenuation for each near-side listener. Hence, my comment about dome-light aiming. When you consider reflections, you may ponder this question : Do you want your main tweeters MORE on-axis, or would you rather have the phantoms MORE off-axis? Bottom line : "on-axis" tweeters might make sense in a larger, less reflective environment for more centrally-seated listeners. But don't try to force-fit home-audio thinking where it just doesn't apply.” Lycan.
“… The frequency at which the first comb null appears will depend on : the time delay between primary source and reflection (or between primary source and image). The depth of the first comb null will depend on : the magnitude of the reflection (or image) compared to the primary source. If the magnitudes are identical, the null will be infinitely deep (perfect cancellation). If the magnitude of the reflection is only half of the primary, the null will only be 6dB deep. Never a really good idea to try to EQ nulls .” Lycan.
“Using reflections to create a "larger than life" soundstage is a dicey proposition. The naturally wide stage that basic stereo is capable of achieving does not "depend" on reflections to achieve it; and, consequently, we often find in small, reflective environments that taking steps to reduce reflections will actually widen the stage ... “ Lycan.
“In summary : below 200Hz, aiming doesn't matter. At higher frequencies where the driver starts to BEAM, aiming starts to matter. So the only answer to the question : does it matter how I aim my 6" drivers? is this : what frequency range are they playing? If limited to 200Hz and below, the answer is no : it does not matter how they are aimed. If playing well into the midrange AS WELL AS THE MIDBASS, then the answer is yes : the midrange "part" of what they are playing WILL be impacted by how they are aimed.” Lycan.
“Big difference between a concert hall and car: size of the acoustic space! And it's NOT just a relative difference ... there's a real, tangible threshold involved, as defined by the Haas Effect. In a car, there's a real good chance that the natural reflections will not exceed the precedence effect (about 20msec, if memory serves) ... meaning that natural reflections will only tend to smear and confuse the front stage. In a concert hall, there's a real good chance that the natural reflections will exceed the precedence threshold. So if you delay the rear fill by ~20msec or slightly more, you can create an apparent acoustic space that is much larger ... without confusing or ruining the front stage. This is a good thing Yes, we face the orchestra in a concert hall ... a classic argument against dumb rear fill ... but we also sense that the concert hall is bigger than about 25 cubic feet ... a very good argument in favor of smart rear fill ” Lycan.
“... but the real reason not to operate a speaker near its resonance is because that's where it produces the most distortion and at multiples of resonance. That distortion cannot be filtered electrically (yet), and it's high-frequency content that makes localizing the speaker easier. Couple that with all the turbulent air movement when the cone has to move a long way and it's a recipe for winning the "Where's Waldo" game. Seriously, minimize the excursion and the system will get well fast.” Andy Wehmeyer.
“... When there are two sources for a sound that are identical in frequency and time, we hear a phantom source in between. That's why we hear a center image in a stereo system. If we have a speaker and a reflection that have the same frequency response, we'll hear a phantom image inbetween. If the frequency reponse of the reflection is NOT the same, then the image will be placed differently for sounds at different frequencies. If 1kHz is louder in the reflection, 1kHz will image closer to the reflecting surface. At the frequency where the speaker and the reflection are out of phase, we'll hear two images (or no image, depending on your perspective). This causes images to wander around.” Andy Wehmeyer.
“... Putting a center channel in the top of the dash is a little different. We hope for the best in terms of the big suckout from the combination of the direct and reflected sound from the windsheild and we use the windsheild to provide a phantom image that's a little higher than the location of the speaker in the dash. This works great, but it does provide some image spread for the center because the sound of the center speaker will reflect off the WHOLE windshield and the door glass.” Andy Wehmeyer.
“… Here's the deal. Everyone explains time alignment as a way to "move the nearest speaker so it sounds like it's farther away". That's BS and it's a lazy explanation. There is a way to "move speakers electronically", but it isn't simple time alignment. Using time alignment won't make your stage wider or make sounds that come only from the nearest speaker sound like they come from a source located farther away …” Andy Wehmeyer.
“… In cars, we hear all of the reflections and the initial sound as one event - that means we hear the speaker's power response, which is the average of the frequency response at all angles. If we use the speaker above all the way up to 12k, we'll have a big fat hole in the off-axis response where the high frequencies contain far less reflected sound. If we aim the speaker so that our ears get the high frequency sound the on-axis response will have wide bandwidth, but the reflected sound will lack high frequencies. When we tune the car using an EQ, we'll want to boost the high frequencies to smooth the response, but that'll make the on-axis response too bright. It's much easier to make the car sound good if we can make the reflected sound as similar in frequency response to the initial sound. Then, when we EQ, we'll have smoother coverage over a wider listening window.” Andy Wehmeyer.
“I have many more .. but still a few that I understand clearly ...“ Tendean17
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