Impious

Getting sort of off topic.....but no, running a 2-way active front stage + subwoofer is a 3-way active system. A 3-way active front stage + subwoofer is a 4-way active system. Majority of people are already running their substage "active" by using the amplifier's or headunit's onboard amplifiers for the crossover. So when I was having this same argument and including the sub in my setup and claiming to have a three-way active system everyone on this forum was like no you dont have one, dont include the sub stage. Why was that? (not arguing just looking for some clarification). **I do understand how people are using there subwoofers with there headunits and amps to make it active and all that stuff. I cant remember when the thread was made but Ill search for it. Because subwoofers are generally a mono source. Your front stage uses a stereo source. 3-way + sub is accurate. It's all a part of the same system.

Why couldn't it? A properly designed enclosure is required, as in any other situation. The benefit is the large surface area of the drivers which reduces excursion requirements for a given output level, which keeps the driver's excursion further within it's linear operating range which will reduce distortion compared to similar drivers with less total surface area operating at higher excursion levels.

x2, Because I was going to go out and buy some clamp meters and so on, if that is the case then Impious you saved me some money then? If it's something you just want to play around with in your driveway, there's nothing wrong with it. However the information you record won't really have much utility.

Pretty much. But really, does it matter? +/- 30% variation in power isn't going to be audible.

There is. But it requires a bunch of equipment that most forum users don't have access to. A distortion analyzer, dummy load, and stable power supply are a step in the right direction.

Poppycock. Two 18's can be excellent for sound quality. I would use 18's myself if I could fit them....in fact I had a pair I was planning to use but decided against it due to the amount of space they would consume. As to the original topic, I agree; Don't go ported with that amount of space.

Erm, okay

I don't get what you guys are laughing at. I see nothing wrong with the install.

No idea. I'd have to read the thread.

Please bare in mind that clamp tests are not a very reliable or accurate test method, and not a method that should be used to compare one amplifiers performance to another for daily use applications or to determine the "actual" performance of any single amplifier. If I recall correctly RF claims their amplifiers will still make rated power down to around 12.5V, I believe this is part of the reason why the "birthsheets" show higher power output than rated (birthsheets are @ 14.4V). RF amplifiers are CEA-2006 compliant so they must state power is "rated" at 14.4V, but that doesn't mean they can't design the amplifier to still provide rated power at lower voltage levels. I didnt say anything about this test as being used as the holy grail, he asked what they do around 12 volts and I just posted a link for him to look at. I didnt want to say they do this so I posted what the owner of the company posted as a guide or reference to what their capabilities can be thats all; instead of me answering a question I have no facts on so I gave the OP facts. I understand. I posted my comments so others reading the thread, including the OP, didn't base decisions upon the information contained in the linked thread as the method used is inaccurate and unreliable and it has as of yet to be pointed out. Going forward, when linking to relatively unreliable or inaccurate data in response to a specific question asking for actual data it would be helpful to everyone if you included a short comment in your post indicating the inaccuracy of the provided information. In actuality, the linked thread doesn't answer the OP's question at all, and a clamp test doesn't represent "facts". It's data, unreliable data...that's all.

Getting sort of off topic.....but no, running a 2-way active front stage + subwoofer is a 3-way active system. A 3-way active front stage + subwoofer is a 4-way active system. Majority of people are already running their substage "active" by using the amplifier's or headunit's onboard crossover as the filter.

Please bare in mind that clamp tests are not a very reliable or accurate test method, and not a method that should be used to compare one amplifiers performance to another for daily use applications or to determine the "actual" performance of any single amplifier. If I recall correctly RF claims their amplifiers will still make rated power down to around 12.5V, I believe this is part of the reason why the "birthsheets" show higher power output than rated (birthsheets are @ 14.4V). RF amplifiers are CEA-2006 compliant so they must state power is "rated" at 14.4V, but that doesn't mean they can't design the amplifier to still provide rated power at lower voltage levels.

Keep in mind part of "sound quality" is accurate reproduction of the material, which includes sound level. It can require a good bit of output to properly reproduce an organ or piano, and having sufficient output capabilities to handle dynamic peaks that occur in well recorded source material is also required. For example, it takes a fair amount of displacement to accurately reproduce the 18hz organ in Planet Kryptonite. "Sound quality" and "loud" go hand in hand as an inability to reproduce the material at realistic levels would be a failure to achieve the initial goal of sound quality. Too many people (not necessarily you, just in general) equate "sound quality" with "quiet". That said, there is a large difference between designing a system with sufficient capabilities to reproduce the source material at realistic levels, and the typical use of the term SQL which is all too often supposed to mean "Hey guys I'd like to be able to hit 145db on music without it sounding like total crap"....which has no semblance of sound quality, hence the problem with the term "Sound Quality Loud".

There is nothing to be gained sound stage wise from having the subwoofer mounted in front of you.

That statement is so horribly inaccurate it's painful. It will completely depend upon the specific speakers being installed. Especially in car audio where the vast majority of drivers are designed to work optimally IB. Most companies want the consumer using their product to obtain the best performance possible from their products. Most car audio companies understand the vast majority of consumers are just going to toss speakers in their door, and as a result design their products to perform best in such an environment. Are there some car audio speakers that may perform better in an enclosure? Yes, it's possible. But to make the statement that an enclosure will "yield the tightest bass with most components and cleanest SQ" and state it as a fact as opposed to opinion (which is evident from the first part of your statement, "regardless on opinions") is simply a display of immense ignorance. It is far more likely that they were designed to perform optimally IB than in an enclosure. I also think that a tweeter should be mounted backwards...max reflectivness for the square wave X- E=MC3 crist dude...if someone states "regardless of opinion" on the internet you Don't take it seriously .....LOL it definately gave this thread a kick start though.... The problem is other people who are less experienced may read a statement that's worded as though it's fact, when it is not, and consider the information trustworthy. This is how all of those myths continue to perpetuate. Which is why it's important to denounce those inaccurate statements when they are made.

That statement is so horribly inaccurate it's painful. It will completely depend upon the specific speakers being installed. Especially in car audio where the vast majority of drivers are designed to work optimally IB. Most companies want the consumer using their product to obtain the best performance possible from their products. Most car audio companies understand the vast majority of consumers are just going to toss speakers in their door, and as a result design their products to perform best in such an environment. Are there some car audio speakers that may perform better in an enclosure? Yes, it's possible. But to make the statement that an enclosure will "yield the tightest bass with most components and cleanest SQ" and state it as a fact as opposed to opinion (which is evident from the first part of your statement, "regardless on opinions") is simply a display of immense ignorance. It is far more likely that they were designed to perform optimally IB than in an enclosure.

Car audio drivers are typically designed to perform optimally without an enclosure. You would have to email JL Audio and obtain the T/S parameters to determine what if any enclosure size might "improve" performance.

First you need to know the actual outside diameter of the tube. If you have 20.75" internally & need 8" of clearance, then you can only have 12.75" of port inside the enclosure. Then the volume of the port inside the enclosure would be; V = Pi * r^2 * h Where r is the radius of the OD of the port and h is 12.75" You would then subtract V from the 5.38cuft of enclosure volume you've already calculated, so you would have; 5.38 - V = net enclosure volume You would then use the following formula to calculate how much total port length you would need; Lv = (Av*1.84*10^8)/([Vb*(Fb/0.159)^2] - 0.823*sqrt(Av)) Where Av = area of the port, Pi * r^2 Vb = net enclosure volume Fb = desired tuning frequency It's basic math, you can work out the calculations.

MECP certification is a joke and most of the better shops realize this.

Completely depends on the subwoofer being used.

Kind of but I really want do see how good of a sound stage i can get from it. Good luck with that. Chances are good it will make the stage worse unless you go to a lot of effort to eliminate the transfer of tactile sensations and rattles, which will draw your attention to the location of the subwoofer. There's nothing about subbass that makes putting subs up front "better".

People have put subs in their doors before. By the time you add the weight of a subwoofer, amplifier, fiberglass/etc.....you may be in need of new door hinges. You also have to consider the subwoofer you plan to use and if you can work an adequate enclosure into the door. Are you wanting to do this just for the "wow" factor?

if u had that saz-4500d with those 15's, would consider running a spar battery and maybe an compacitor? Is English your second language? You have no business running that high powered of a system as you obviously haven't much experience or knowledge and will end up either wasting money or blowing stuff up (or quite possibly both). Slow your roll would be my advice.

http://www.wooferset...nent-System.htm http://www.wooferset...nent-System.htm The 6x9's are supposed to kick ass, not much talk about the 5x7's however.