ibanender

WTF are you smoking? Unless the car has been wrecked, then yes, as long as you know even a little about them then they are instantly loud..... So why don't you have one, and why are there other vehicles used, and why are Explorers and Cherokees beating CRX's? I can think of 3 people right off that combined have had 6 or 7 CRX's, none of which were loud, only 1 was wrecked. Why is the vehicle excuse used all the time? Every time somebody has anything pretty loud, it's because of the vehicle? What about Excursions, are those loud? How about a no wall Excursion doing 158's @ 29 hz on the dash? Must be because Excursions are loud.....

Whichever amp these audio gods say is better, because they talked to some people who said they were. Actually if you read my last post, I've proven conclusively that Sundown is in fact overrated. It won't do 1500w because it's not .97db louder than a 1200w amplifier. So do you want an amplifier that isn't underrated, or an amplifier that is overrated? <---- Still using ibanender logic. Oh, so you used your test method to prove the DD does 1200 watts?

If you actually read it, you'd see that I explained everything in detail, with no contradictions. If I was trying to change the subject, I'd insult your mother, your sexuality, and your intelligence. Perhaps you should question everything you post when somebody questions your godliness. I'm done with you on this forum, period. There's no point in putting effort into anything you're associated with because it will just end in your rambling about things you've convinced yourself you know about and won't consider anything anybody else has to say.

Ok Im sorry for the way that came out.. in my current setup in a hatchback Im very pleased with what I hear, and I have yet to hear it in the truck, so my opinion is based soley on that. I guess it really depends on the guys tastes, if he dont like it Im sure we will try something else, but were kinda hopeful that this works, cause aesthetically hes very pleased with it so far. **This isnt my build, this is my customers, so we had to come to some comprises on fitment, looks and sound. And ultimately its his, and if he likes it Im happy Acoustics of that car, TOTALLY different than the truck.

Bottom line is pick something, start with it, if you think it could sound different, change the box, and learn from it. I know everything I know from building hundreds of boxes and observing changes. Care to point out where? There are multiple factors, I made points on all of them. No matter the motor force, if more air CAN be displaced, it should be bigger, and there is a point where it's too big. More motor force allows for bigger ports to work better. Prove it. Do you actually build anything, or just play in WinISD and read forums all day? Have you ever been a part of subwoofer design, at all? Since you're the modeling master, have you ever taken an accurate measurement to a port to test the validity of the velocity estimation? You're assuming it's correct, but have you ever tested it? How is what I'm saying garbage? You say it is, with no explanation. Right, why listen to the guy who helped design the driver, has been using them for 4 months before a consumer did, continues to improve them, and is part of the reason why the driver he's using is the way it is. Clearly, a generic calculator is the best option, it knows more than I do about the sub.

What? I work in a ton of different industrial environments. I've never seen that before. What app are you talking about? I'm not 100% sure, but I recall Dan Wiggins telling me that years ago. Someplace had it in a place he did some industrial noise cancellation solution for.

And honest, from first hand experience I'm going to have to beg to differ, port noise is nill with the setup, port area is dead on. I've used ports Luke this on this specific sub and I know it works. Now for the truck, can't speak for that yet, but I've done quite a few trucks and I feel pretty decent about this one. Who's knows, you might be right, but I'm pretty sure your gonna be 100% wrong. Maybe I have higher standards? I happen to own a 99 GMC Sierra, I'm quite familiar with them and what they like vs not like. Downfiring works much better than forward firing, and every box I've ever heard that had a very narrow and wide port had audible noise. Even the port in my truck, which is 12" x 2" for a single 12 is noisy.

Then take that model, and forget everything it says. They aren't at all accurate, period. Box volume has everything to do with port area. If your volume is too small it will choke the port, if it's too big it won't resonate. There is no blanket answer for every sub, because there are other factors that determine what is too little or too much port for a given sub. You can only go by a "general idea" to get you started if you aren't super familiar with the sub. Yes, this is true. You require more port area for more displacement, this goes for more subs or just plain more excursion from a given size. But, there's another factor also, motor force. How much motor force and how linear it is through stroke makes a big difference too. Example, if you had a high throw suspension with an underhung coil, it could move a lot, but it wouldn't be doing it much on it's own power as it would be inertia. So, after the bottom of the coil goes past the top plate, there's no more "umph" left. If the coil is always well in the gap or there is something like XBL^2 going on, there will be motor force still working through full stroke, which will work better on a larger port.

Fs won't play that big a part in the sub bass game either So a sub with a 45 hz fs will play 20 hz just like a sub with a 30 hz fs? In an anechoic environment, no, in an enclosure is a different story. Do you listen to your music in an anechoic room? In an enclosure, same story. A sub with a 45 hz Fs in a box tuned to 20 hz and playing 20 hz will sound like ass across the board. It will play it sure, but the frequency response will just be a gradual taper down to the playing frequency. If it were say, a 40 hz tune box, it would be relatively flat response till below tuning, where it would fall off quickly. There is a reason home theater drivers have a 15-20 hz Fs and similar tuning. Playing a full octave below Fs just won't have authority. Would it blow your mind if I had one?

If your wood doesn't suck, screws do just as good of job I wasn't implying screws suck period.. That was taken out of context. What i am implying is excessive use of screws is bad. I havent been in this topic in a while but i'm pretty sure that's the point that was being expressed by me when i was stating using screws like i see many people do to screw their baffles together is pointless.. I've seen people use around 60 screws just for that!?!?! Instead, it would be quicker and probably stronger to just lay a large amount of weight on the center of the baffles and clamp the hell out of the sides all the way around. But.. this is more technique than the only way.. Since there is no only way to do it.. this really isn't debatable. Excessive screw use isn't bad, it's not necessary. There isn't a negative effect, just "overkill". There are some people that legitimately believe (and I'm not sure how it got started or spread) that leaving screws in a box WEAKENS the box. Yes, they believe that leaving metal that is used to make a bond tight is more detrimental than leaving a void in the wood. You'd be surprised at how dense MDF isn't. In some industrial applications, it's actually used as an air filter.

THAT is real world testing, funny how that works out..... Might be "real world", but still not meaningful unless you can verify that all variables were constant, accurately measured and what information is needed. How meaningful is that result if the gains were set differently? What if the subs were hotter and had higher power compression or more impedance rise when the DD was tested? Or other variables were changed? What if, what if, what if. There are dozens of variables that could have affected the results. How meaningful is the result to someone not worried solely about SPL numbers if the Sundown was clipping and the DD was not? If the Sundown had excessive distortion and the DD did not? Hell, a .6db difference isn't even close to being audible, so that itself is meaningless to someone not interested solely about SPL numbers. Yet again another reason why "real world" testing is "real meaningless" unless all variables are known and controlled. Yet another instance of ibanender incorrectly assuming all results are meaningful and accurate because it was measured in the "real world". "Real world" proof the Sundown is better in all circumstances and for all situations right? Wrong. Funny how that works. So now you're arguing that the results that he tested aren't valid? Nobody said a given model has a definitive power output. As a matter of fact, EVERY amp will have different output. Will it be audible? No, but it's different. That 0.6 dB is roughly 15% more power. If you gain SPL, that's a meaningful test, period. Those are the numbers the manufacturers advertise. If you don't like that one is one way and the other is another, why not take it up with these standards you're so set on? Since you agree that manufacturer ratings are not necessarily correct, how is that any different from an individual doing their own testing? NOW you're getting my point. According to you, they hold the same warrant then. So ANY specs given by any manufacturer are false, and you should just buy something to buy something because everything is not believable. Funny, isn't that exactly what I said earlier? They dont list THD because THERE ISN'T A STANDARD FOR MEASURING IT. EVERY amplifier is 1% or less at some point, and no manufacturer has a playbook for how it should be measured. I never said it couldn't be measured, I said it's not measured accurately to compare across other amps. YOU keep saying distortion this and distortion that and what power does it do at what distortion, but you can't give a single example of a manufacturers spec of distortion at the full bandwidth of the amp, at rated power. Manufacturers don't do it (or at least don't publish it) because the data is compared as something important when making a purchase decision against other terrible products that cost half as much. Class D has a lot of distortion in it compared to A/B, but can you hear it on a sub? NO. Why? If a sub in itself is 10% distortion, you won't hear how dirty an amp is till it's more distorted than the sub is anyway. Then, beyond that, the only people that seem to care exactly how much power they have are aimed at output. How does your ear interpret 150 dB? It's certainly not clean! So now your body can't tell how bad it is either. Moral of the story, you're the only one that seems to care. It's like you got your feelings hurt because somebody tested your favorite amp and it sucked.

I'd be willing to bet the port will be very noisy and it won't be very loud. Aiming forward in those trucks doesn't do so hot and it doesn't look like there is enough port area, and the port shape itself looks very indicative to noise.

I wouldn't go over 12 sq in per cube, and not less than 8 sq in per cube for any reason

Fs won't play that big a part in the sub bass game either So a sub with a 45 hz fs will play 20 hz just like a sub with a 30 hz fs?

I'm not sure 100% what you're trying to accomplish here, but maybe this will help. http://www.mcsquared.com/modecalc.htm

There's more to it than the specs. The V2 performs better and handles more power, it's a completely different motor and coil.

THAT is real world testing, funny how that works out..... That's as much as I read, because you can't teach somebody who isn't willing to learn. But lets just look at something here. According to the standards you say manufacturers adhere to, these 2 amps will sound just as good as each other and do the same power: http://zapco.com/Reference.html REF1100.1 4 ohms: 1 x 825 Watts 2 ohms: 1 x 1100 Watts T.H.D. + Noise: <0.03% @ 4 ohms. http://www.legacycaraudio.com/itempage.asp?model=LA1110BK 1 x 1100 Watts 2 Ohm Stable S/N Ratio: >95dB THD: <0.04% And why is it that most manufactures don't even list THD as a spec? This is one of those things where the SAZ was a better amp in your setup. For others, it may be the opposite. The only time I've seen consistent amp swapping results be the opposite of the norm is in extreme impedance rise cases where 1 amp works better on higher impedance loads than another, IE higher voltage output capability. It's a rare occasion, but happens, and usually only when it's being used at a higher DCR than lowest recommended.

3000GT's have a stupid shaped cargo area, and it's very shallow. There isn't' enough space to do an 18 properly without it being a wall, period. Cabin size won't matter if your box sucks to start with. CRX's are NOT instantly loud, and less cabin space does NOT = louder. There's a lot to be said for vehicle acoustics, some are better than others, and that applies for SQ and SPL. The Blazer will be louder in no wall scenarios. In terms of the car itself, the 3000GT will be less fun to drive when you add all the weight of a stereo, period. Not to say it won't be fun, but it won't be what it was pre-system. Also as mentioned, parts are far and few and pricey, and it WILL need fixing. I'd wanna know when/if the transmission was replaced in it too. If it hasn't and it has over 70-100k miles, you'll need one soon. The Blazer has parts all day long, cheap, and should be reliable if it's been taken care of. I think the Blazer is a better buy, for driving and stereo.

Correct, power at a given condition is what it is. In a given vehicle, the reactive load is repeatable, over and over. A simple oscilloscope will show if it's clean or not, it won't give a specific percentage. That takes a more advanced device. And again, if 10% is inaudible, does it matter if it's perfectly clean? No. If the systems kept gaining, it wasn't clipping a lot. When you reach major clipping, your score will go DOWN. Your power doesn't go up, your heat does. Since you don't believe in real world testing, you wouldn't know that from actually testing things. I am going to stop responding, because there is absolutely nothing anybody can say to get you off of this idea that all specs must be measured to a standard that is uniform to have an accurate result, when there isn't a standard that is followed precisely because of equipment variance, user error, not not specific enough conditions. I didn't even bother reading all of that because quite frankly, I don't give a shit. I measure power with amperage and current, it directly reflects my score, and if it sounds fine I don't care how much distortion is or isn't there. That's how everybody outside of anal retentive people work, they don't need a spec to tell them it sounds good, they just listen to it. I'm guessing no, for the reasons I just explained.

Reactive loads is what makes it REAL power. Resistive loads don't prove anything, you don't listen to resistors, and it's called impedance because it changes. You don't have x ohms all the time. If it's rated for 1 ohm, you may never go below 1.6 during play, that 1 ohm power isn't what you're getting. Please tell me you don't look at THD spec on an amp to compare them. There is no standard for THD measurement. Distortion could vary at a given frequency, voltage, anything. Beyond that, do you have any idea how distorted subs are to start with? I'd be willing to bet up to 10% distortion, the ear can't differentiate. Distortion will increase power on a meter, fully clipping however will show LESS power. CEA-2006 is a joke. An amp could be rated at 1000 watts @ 14.4v @ 1 ohm under that system, but in a car it will get something like 650 watts in a car. Why? Because you don't have 14.4v, you have 12.6v, and then you have impedance rise. You don't have any of the conditions the amp is rated at. Is there a distortion standard? What equipment is being used to measure that distortion? Is that equipment equally calibrated to each other? What frequency is it tested at and is it tested the same way for every amp? Is the same output level being used to check that? Are all those same standards used to get the power rating? Your same reasons for "real world" numbers not being accurate also apply to every manufacturer rating their amp, even in a "standard of measurement". Yes, real world DOES mean it's accurate and useful. In THAT vehicle with THOSE conditions it did THAT number. Will you have those exact conditions? Maybe, maybe not, but at least you get an idea of what it's capable of in a vehicle and not on a bench with a resistor. The only way a test isnt properly conducted is if you fail at basic math and can't multiply 2 numbers. Can those conditions be recreated? Sure, that same vehicle has the same conditions, if you test one against another, you have accurate results. You've used the same scenario with the same test equipment. Bottom line is anybody who is concerned with actual output probably has their aim at SPL, where distortion doesn't matter. Power is power, it does it or it doesn't, and an SPL meter doesn't discriminate. If 1 amp does more power than another amp, odds are, SPL went up. The testing you want will never be done, because every manufacturer would have to use the same test equipment, calibrated before every use, under standards that would only be adhered to by honest people.

My problem is i have 2 subs with quad 1 ohm coils. So is it more exspensive to make one run at 2 ohm. I think the problem is having quad 1 ohm coils. There's no reason to have a quad coil sub unless you plan on running 8 amps to it. Have you tested efficiency at different loads before? I've tested Class D's that are more efficient at lower impedance than higher, until below rated, then it just goes to hell. It's all subject to the components used.

The tuning of the box wont determine what your truck with peak at, not at that low of a tuning, will it? I would see if you were tuned above your peak freq (considering you already know that number from previous builds) it would change your peak tone, right? Depending how hard the vehicle itself peaks, the box could change that. If the box peak is stronger than the vehicle peak, the box peak will be louder. Most vehicles don't naturally peak below mid 40's. The only potential exception is if you're box is peaking an octave below vehicle frequency, then you could be using both.

What's that gonna prove? The box volume ported will be too big for sealed, the alignment would be WAY off. The concept behind using a sealed box to find vehicle resonance works, sorta. You have to have the optimal sealed box volume to give a flat response (in open air anyway), you also have to have the speaker in the same position, firing the same way. Another factor I've found is the louder you get, the more the frequency can change. The sealed enclosure wouldn't necessarily need a flat response or be in a certain alignment as long as you had a method by which to reliably measure the enclosure both inside and outside of the vehicle. Doing this you would be looking for relative differences in response rather than absolute values.....the frequency with the greatest variance between interior and "anechoic" (outside using proper measuring techniques) measurements would be the peak frequency. You are probably right that as things become highly pressurized and resonating the frequency will change so it's not perfect, but it might help get someone in the ballpark and a starting point to fine tune from. SPL ain't my game though. And I realize this would be extreme overkill for answering the OP's question. Yeah, you could take the difference and figure it out, but that's more testing that is really necessary when you could just build the right box to start with. I will be the first to tell ya, low volume (say 130's) when your SPL setup is much higher (say 150's) testing isn't accurate, it could be off by quite a bit. Will it give you a start point? Yeah, sorta, but it sounds like he's already got a starting point based on what he's said.

A SAX-200.4 will definitely do 500x2 @ 4 ohms You are asking the wrong question. What you need to focus on when asking this question is amplifier efficiency rather than just the impedance of the load. If both amplifiers were the same efficiency into those respective impedance loads, there would be zero difference in current draw. What ibanender is likely eluding to is that most class D amplifiers will be more efficient at 4ohm than 1ohm, so the 4ohm impedance would likely result in less current draw. But the reason is because of the difference in efficiency, not impedance. It just so happens that efficiency is generally correlated with the impedance of the load the amplifier is driving. The same difference in current draw could occur between two different amplifiers of the same power driving the same load simply because of a difference in efficiency between the two amplifiers. So, moral of the story.....current draw is directly related to efficiency, not load. Efficiency is generally correlated with the load (lower the load, lower the efficiency). But efficiency of different designs and amplifiers will be different, so driving a higher impedance load does not guaranty a higher efficiency when comparing two different amplifiers. Yes, if both amps had the same efficiency at their respective impedance, they would have the same draw. Class D amps ARE more efficient than Class A/B. However, a 1 ohm Class D amp is more efficient at 1 ohm than 4 ohms. A Class A/B rated for 4 ohms is more efficient at 4 ohms than 1 ohm, and a Class A/B rated for 1 ohm is more efficient at 4 ohms. It's how the technology works is what I'm getting at. You summary is pretty spot on though, the efficiency of a load is irrelevant, the efficiency of the amps design will dictate it's efficiency at a given load.

........ According to the website they are rated at 14.4v. It's certainly possible they will output their rated power at 12V (though I've never seen any actual bench test results). It's also possible Jacob actually used 12V to come up with the power ratings and decided to list the rated voltage at 14.4v instead. But the website and manual state 14.4V. I realize the website says that and the manual says that, but that's part of how the business is operated. Under promise, over deliver. They are rated so you WILL get the power it says it will do in a car on 12v. When they rate an amp, they don't go "well this is what the build house says it will do on 14v, so we'll rate it that". How is that? That's real world numbers. It does xxxx watts on xx.x volts at x impedance, you can't really misinterpret that. No, there was a time when DD forum was FILLED with complaints of dead amps and not getting them back for big events and finals. Maybe they fixed it, I dunno, but there was a time probably 90% of their amps failed. Also, just because 1 person uses 1 and it's fine, doesn't mean there isn't a problem most others experience.