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Premature post. Cascade and Second Skin sell very good products. All of the liquids and pastes are vibration dampers. As I mentioned, you don't need a lot of supplemental vibration damper on the floor. That means you'd need to use these products as barriers. They will be less effective in this application since they are tightly bonded to the sheet metal. More importantly, a barrier's performance depends on how much it increases the mass of what is already there - you need to double mass to gain an audible improvement. Adding 1 lb/ft² to sheet metal that starts around 1/2 lb/ft² does that. Any idea how thick the application of a liquid product would have to be to get to 1 lb/ft²? I don't remember, but it think it is 6mm or so, roughly 1/4" inch. I can't even guess how many cans of an aerosol it would take to coat the entire underside of even a small car to that thickness. You would need to cover the entire underside since sound will bend around a more difficult barrier to follow an easier path. Here's something else to consider when you contemplate a treatment that needs to be permanently bonded to a vehicle's sheet metal. What happens if you need body work? I've been wondering about this for some time and is why I encourage anyone who isn't building a one purpose or disposable vehicle to make as few permanent changes as they can to get the results you want. I've been sharing a building with a body shop and now have an informed answer - it can make a minor repair a major repair that insurance won't cover. PDR won't work and panels that could be repaired will have to replaced because of the time required to remove layers of vibration damper. Since there's no performance advantage, why do it?

I am thinking late 80's early 90's but just a guess. I did find some gut pics for you to compare to and a manual if you don't have one. http://manuals.harman.com/JBL/CAR/Owner%27s%20Manual/GTQ200-400%20om.pdf http://ampguts.com/gallery/showgallery.php?cat=972 Hope that helps and good luck with it!!

Danny, Some of that depends on how you define "outside noise". If you mean noise that doesn't come directly from your vehicle or its interaction with the environment, doors would be first since they let in most traffic noise. Doors make a good first project. They can be done without disturbing the rest of the vehicle. I know from personal experience that you can drive a car for days without trim panels. On warm days you can drive without glass Noise rejection treatments involve installing a barrier. If you hang this layer from the inner skin and have door mounted speakers, you'll also be isolating the front and rear wave coming from the cone, improving speaker performance. An interesting thing happens when you start by treating one area. In a noisy car, you are sitting in a swirl of sound coming from every direction. This makes it difficult to localize the sources. Treat just the doors and you are likely to be able hear engine, exhaust and tire/wheel noise better than you could before. It's not louder, just easier to localize and identify. That leaves noises generated by the vehicle - engine, exhaust and its interaction with the environment - tire/wheel and wind, maybe rain too. Engine, exhaust and tire/wheel noise are complicated. The firewall and floor are where they penetrate, but not exactly as we tend to think. Engine and exhaust noise do hit the passenger compartment in a direct line, but they also reflect off the pavement, meaning they even enter through areas from which you can't draw a straight line back to the source. Tire noise is especially interesting. Most of us think that most of it comes in through the wheel wells. That's led to all sorts of exterior treatments that are supposed to avoid the complication of getting to the interior surface of the floor. It seldom makes an audible difference. The important point is that tire noise starts at the contact patch with the pavement and radiates up in every direction from there. A lot of the sound that would otherwise pass through the wheel well is blocked by the tire and wheel. The reality is that tire noise enters through most of the floor. Interestingly and despite years of tradition pointing in exactly the opposite direction, you generally don't need much supplemental vibration damper on the floor of a vehicle, especially if you don't plan to remove and replace the factory application. The floor is almost always braced and reinforced in a variety of ways that make it much less susceptible to resonance than other areas like the doors, roof and quarter panels. Add the bolted down seats and the weight of a human being or more and you are most of the way there. A barrier layer is always going to yield the biggest improvement. Spare tire wells are another area that have been traditionally over treated to the extreme. The usual approach is to remove the spare, tap the sheet metal and marvel at the flimsy construction and extreme resonance. Many wheel wells WILL benefit from some supplemental treatment. The confusion results from the fact that the spare itself is part of the manufacturer's NVH treatment. With the spare in place, the well has completely different characteristics. The roof is interesting. Glass will always be the weak link in any noise attenuation program. This isn't as big a problem as we might fear because most of the noise we are concerned about strikes the vehicle below the glass line. What this means in terms of treatments is that a barrier isn't going to help much unless you are frequently exposed to noise sources directly overhead. I had one customer who spent a lot of his day driving around an airfield. For most of us it isn't a problem. Resonance can be a major problem for the roof, especially since it is such a large panel, right above your head. This resonance can be excited by a wide variety of sources. My rule is to tap on the roof from outside the vehicle. If it rings, treat it. If not, it's probably not worth the effort.

Too many funni shit in here. Why does a shrunk down motor and less weight make people think 'less boom boom'? Its yesterdecade thinking, and people lacking any real knowledge.. Not consumers, the INDUSTRY. Fi are doing something trully unique, going back and re-engineering and innovating. Remember how big cellphones were in the 90s? how big is an iphone today? they dont even compare today. Thats called innovation and real knowledge. Everything out there looks cloned and like I could run to china at Manupacker it myself. Fuck that.

if i picked up two of these I think I would wire them in parallel then run them off of a 125.2 lol! at 4ohm which would mean what 200rms per driver! lol! also how much depth is required for these speakers! it looks like a good 3-4inch! if so I have that to spare lol! summer project here i come! lol

Because then you deal with the complications of internal bracing? Yes, there are adverse affects. I NEVER use internal bracing. Why? I'm sure bracing in an acoustic suspension enclosure, a 4th order, or a 4th order bandpass wouldn't hurt. Wherever there is air flow, it causes problems. Perfect example (and not the only case), in my S10 I did no internal bracing and made the box 5.25" thick except for the baffle which was 6" thick. If you put ANYTHING in that box, score dropped. I left a drill in the box once and lost over 1 dB. In other smaller box applications, I've heard turbulence from bracing as well. Depending how your brace is, I could see it causing a problem with phase or standing waves. The only bracing I'd deem usable is thick threaded rod. Don't assume everyone is concerned about a "score". Acoustic reproduction might just hit the list as important... While they may not be concerned with a specific number, if they want "loud", that's a "score". Loud is loud, whether it be an ear or a meter. The same way you make a daily system loud, you make it loud for a meter. Your acoustic reproduction won't be accurate if you have turbulence and audible noise from it. Standing waves will give dips or spikes in response, a direct relationship to accurate reproduction. The OP asked about good enclosures not loud ones. There are a ton of people that don't care about loud at all, reference levels perhaps, but loud has connotations that are all negative IMO. If you said linear, flat, capability to blend or something sure, but loud not so much. As for your acoustic reproduction comments, true if you have audible noises it will take away from it but flexing panels will cause way worse distortion than any bracing techniques. Bracing will also help to stop standing waves and alter the inner shape of the box to a less symmetric rectangle which is also of benefit but of course we are discussing subs here which play sounds with LONG wavelengths. A solid built enclosure IS a good one. "Loud" is what you make it. Why do SQ guys have 600 watt front stages, then don't go over 90 dB? "Overhead" isn't THAT much. Having an extra thick box solves the flexing problem and won't induce any other noises. Will bracing help stopping standing waves? Sure, but so will changing the box shape. Don't make your box a cube, problem solved. There is such a thing called a "golden ratio", which should pretty well guarantee no standing waves. Besides, even if you had as standing wave of some variety, you're assuming response is linear in a lab or simulation. What about the vehicle's effect? You shouldn't have a problem with standing waves with long wavelengths anyway, unless your box is huge.