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What is sensitivity? The sensitivity of a driver is typically defined as the sound pressure level of the loudspeaker given 1 watt of power input, measured at a distance of 1 meter, measured on-axis with the loudspeaker and measured in infinite space with the loudspeaker mounted to an infinite baffle. While the later part is typically assumed but not stated, the former part is the reason you generally see “1w/1m” or “2.83V/1m” stated along with the sensitivity specification. But wait, is 1w/1m equal to 2.83V/1m? The answer is only for an 8ohm impedance driver. We know this because of ohms law, where Power = Voltage^2/Resistance. If the load is anything other than 8ohm then the resulting sensitivity rating will not be a 1w measurement! If the driver is 4ohm and the measurement is a 2.83V measurement, we can find the amount of power input with the formula 2.83^2/4 = 2w. This means that sensitivity will be overstated by 3db compared to a true 1w measurement. I have seen many unscrupulous companies take a dual 2ohm/coil subwoofer, wire the coils in parallel and then rate sensitivity at 2.83V, overstating sensitivity by 9db! Due to these and other variations in rating methods and some manufacturers not even stating a method, it can often be difficult to directly compare one subwoofer’s sensitivity to another’s. However, if you are able to obtain the Thiele-Small parameters for the subwoofer there is one surefire way to calculate an accurate sensitivity measurement for a driver. And that is with the following formulas; Efficiency (N0) = 9.64 * 10^(-10) * Fs^3 * Vas / Qes *To express as a percent, multiply by 100 *Vas in liters Sensitivity (SPL) = 112 + 10*Log(N0) The Efficiency (N0) calculation expresses, typically as a percentage, the amount of power input that is converted to acoustic power. With the sensitivity calculation we can convert the efficiency of the driver to a 1w/1m sensitivity rating. As long as the T/S parameters are accurate, utilizing this formula will put any two drivers on a level playing field and allow you to directly and accurately compare sensitivity (or efficiency) between drivers. Okay, but higher is still better because higher means it’s louder, right? Not necessarily the case. There are a few issues here that need to be discussed to better understand why. From a driver design perspective, we can see from the above formulas that there are two ways in which to increase sensitivity for a given driver diameter; increasing Fs or decreasing Qes (or both). Adjusting either of these two parameters, however, is ultimately going to affect how the driver responds in a given enclosure. And this relationship, as it relates to enclosure size, sensitivity and low frequency extension, has been defined through a rule known as Hoffman’s Iron Law. As you can see from the link (which I highly suggest you read), it’s already been covered in relative detail elsewhere on the site. But it’s important to us here, so it’s worth touching on again. In short, Hoffmans Iron Law states that we can only have two of the following three; Low frequency extensionSmall enclosureHigh sensitivity What’s important to take away from this is that if you want high sensitivity and a small enclosure, you will necessarily sacrifice low frequency extension. Or, conversely, if you desire extended low frequency output from a small enclosure, you must necessarily sacrifice sensitivity. While a given driver may have a higher rated sensitivity, that driver may actually have less output in the subbass region once the effects of the enclosure are taken into consideration since it may begin it’s rolloff at a higher frequency. And given in car audio we typically require reasonable enclosure volumes, having a high sensitivity can actually be disadvantageous. The second factor we need to consider is how output is achieved. Sensitivity isn’t what determines maximum output. Output is a function of air displacement. The maximum amount of linear displacement (Vd) you can achieve is limited by your cone area (Sd) and linear excursion (Xmax). As you increase the amount of displacement at your disposal, you increase the potential linear output you can achieve. Even though a driver may have a higher sensitivity, if it’s maximum linear displacement (Vd) is less than that of a driver with a lower sensitivity, the lower sensitivity driver will have the potential for higher levels of output. We also have to consider the effects of Power Compression (and I again urge you to read the link). Consider the effects of power compression applied to our scenario. A higher sensitivity driver may, for example, begin to experience more power compression at a lower output level than a lower sensitivity driver. If this is the case, then as output is increased beyond that level the higher sensitivity driver would gain less output for each increase in power and experience more parameter shift. The basic summary is that after many factors are taken into consideration, it is impossible to state unilaterally that higher sensitivity drivers will better than lower sensitivity drivers. Generally choosing one driver over another based on sensitivity alone is a bad path to follow. Sensitivity is just one of a multitude of parameters that all conspire together to define the performance of a loudspeaker. And in my humble opinion, it is one of the less important factors to consider. As with anything, there are compromises to be made and it's necessary to find the best set of compromises for your particular situation.

Here is the skinny IMO. If you can run a 3-4" driver completely on axis then you can get away with just a midbass and a full ranger. If you can't get it on axis then a tweeter and a mid-woofer would be a better combo. Obviously there is some gray area between ON & OFF axis and that compromise you can choose from. Being a bass player I would nearly always pick the dedicated midbass and full range driver. Two main reasons. 1) It is the only way to get great midbass in a car, 2) Having a single driver play MOST of the frequency range really helps staging and simplifies a lot of the issues surrounding installation in a car. That being said. I'd play with your butter dish some more and decide if you are willing to do it. I'll also add that I prefer a 3" full range driver for its reach, but there are 4"ers that can work too. My favorite 4 would require that you add a tweeter as well though which then defeats the purpose.

couldn't get a 2000d even if you wanted it, or at least a new one. i never used american bass before so i cant comment. heres an option there is a sale on the 1000d ($275)get two of them and link them @ 2ohms, then buy 2 z-15 1000wrms ($200)from jacob on sale, also since he only has dual 2ohm you cab easily wire them to 2 ohms. you could do all that for like 50 dollars more than what you were willing to spend on just the amp. now you have amps and subs.

This is going to be your choice, But for the simple fact of customer service sundown is the way to go....

ORLY???? Your an asswipe.

Classic canned spam: Depends on the install. More specifically: the enthusiast. I used to pick on SQL guys. This was when I ran 3k wrms daily and competed with 9k. 12 years later I run 120wrms to my subwoofer and 400wrms to my components & mids. While I do appreciate more "powerful" sub installs, there is nearly NO need for it anymore. As far as in competition - totally depends on the install.

You know you have a car audio addiction when...

Wow man good work on everything. The door pods look almost factory in texture and color. And the battery terminals with the plasti-dip look really good, wouldnt have guessed they werent factory!! Very nice build log!!

great fab work and clean build.

Nice install, all those little things you done made a big difference and never seen fiberglassing done that way but it looks easier. Any tips on that fiberglassing method would be nice if you had some spare time (you can pm me if you dont want to clutter your build log), thanks.

Yes, he is coming out with a saz-2500. http://www.soundsolutionsaudio.com/forum/New-Product-SAZ-2500D-t35549.html

Ehh...not really. I would maybe define beaming as a term used to describe the narrowing off-axis disperson of a loudspeaker as frequency increases due to the relationship between the wavelength of the sound wave and cone diameter.

It would not look cool to run just one sub !! Take a look at the ssa dcon; maybe you can have 2 of them. I've never listened to them, but they have great reviews. And ssa products are sooo goooood!

Your going for SPL? Your looking at the wrong drivers then. That is not what the ICON or the Atlas are made for.

Have you come back from the dead because you have 13k posts and I have never seen your posts or remember them lol.