Julian

I can hear a difference from 90kbs to 192.. but that's just because it's a huge jump.. but from 192-320 i don't hear much of a difference.

Power compression is a topic that is rarely discussed, but always important. When you hear someone call various theile/small parameters a “small signal parameter”, the implication is that with larger signals (more power), there will be a shift or change in these theile/small parameters. This is what we call power compression, and occurs in 3 potential ways. The first thing to consider is how theile/small parameters are derived. There are 5 basic parameters from which all other data is extracted. These parameters are Re, BL, Mms, Sd, and Cms. So looking at this from a mathematical standpoint, a change in any of these parameters will cause a change in all other parameters as well. Of those 5 parameters, there are three that can change once power (rather, more power) is applied; they are: Re, BL, and Cms. Now we will review the cause and effects for each one. Re is the measured DC resistance of the voice coil. When power is applied to the voice coil, the metal becomes hotter, and resistance increases. Heating copper by 200 degrees Celsius will double the resistance, which doubles the measured Re; this results in a 3dB loss in acoustical output. Being that this is also one of the 5 basic parameters, you will see a change in all other parameters as well. For example, a change in Re will cause a large change in your enclosure alignment because doubling Re will also double Qes, as demonstrated below: Qes = Re*Sqrt(Mms)/(BL^2*Sqrt(Cms)) This is power compression at it’s finest, and the most commonly mentioned one, known as Thermal Power Compression. The second type of power compression refers to motor force. As power is applied to the voice coil, causing it to progress out of the gap, the motor force (or BL) begins to decrease. This decrease in motor force causes a drop in output and, again, a shift in all other parameters. When the motor force drops by 30%, you've lost 3 dB in output. This is, in part, one of the reasons why more recent definitions (from DLC and Dumax as well as Klippel) of Xmax have defined it as 70% of rest BL. This type of compression is referred to as BL Power Compression. The third type is related to the compliance of the suspension. As power is applied, the voice coil begins to move out of the gap, causing the cone, spider, and surround to move as well. This movement changes the compliance of the suspension, and is known Cms Power Compression. Of the three, power compression is a more gradual process. A quick burst of power will heat the voice coil quickly but it will take a while to cool back down and remain fairly constant. Over a 30 second period, the coil will have cooled down and been reheated several times, so that while you thermal power compression occurs, it's not it does not occur nearly as fast as BL and Cms. In other words, thermal power compression is a much less dynamic issue. BL and Cms power compression are very frequent and occur on every stroke, as a stroke is simply the voice coil and attached assembly moving. For example, playing a 60hz sine wave will cause 60 full strokes in a one second period of time, and since BL and Cms compression occurs at both the positive and negative ends of the stroke, you would actually encounter BL and Cms power compression 120 times a second! Of course, as power is applied, excursion increases, and BL and Cms compression increases as well. This is why it’s so important to find a driver that has very flat BL and Cms curves (measured on Dumax or Klippel) because these curves represent the behaviour of BL and Cms over the stroke; if the curve is relatively flat and extends out fairly far on either side, BL and Cms compression will be of little effect until you reach the extremes. For most installs, BL and Cms compression will be of the greatest concern. For those who compete or have fairly high power stereos, thermal compression will become a growing concern as more and more power is applied. To summarize, Thermal, BL, and Cms Power Compression are all issues to consider, but it is important to understand how to work around these issues while knowing which drivers suffer more than others. A driver with adequate cooling and flat BL and Cms curves out to 20+ mm will likely experience very little parameter shift and, as such, is likely a better candidate for your high end stereo.

I knew it was by Neil.. it was on a different site though!

Or space issues as you can use smaller 16v batteries as the current draw will be much lower... It's something that takes a lot of planning.. And some know how. By the time you factor in the increase in power as a result of bumping the voltage up to 16V, current draw would probably equal or exceed that of the same amplifier running at 13.8V-14.4V. Even excluding an increase in power, if we leave power constant the difference in current draw between 14.4V and 16V is going to be ~10%. And the increase in power would be 100% inaudible. Not worth the time or expense to try to do anything like this for a daily driver system. You're better off focusing on maintaining a proper "normal" voltage than trying to increase the voltage up to 16V+. For competition it can make sense. For daily driver systems, it's complete waste. Agreed very true, not really ideal for a daily scenario.. I was just attempting to rationalize a reason for a daily scenario Brad

RIGIDITY comes from bracing! Without having to have the box 2-3x the thickness! The definition of rigid is Stiff, rather than flexible; Fixed, rather than moving; Rigorous and unbending.

Build a ported box well, it will be able to play all kinds of music! Honestly you're better off porting. If you really Want to get fancy you could make a removable port plug to seal if you'd like. Anyways, it's all in the install and planning man! Building a box.. Is well building a box.. Not hard just gotta have the tools and patience!

Or space issues as you can use smaller 16v batteries as the current draw will be much lower... It's something that takes a lot of planning.. And some know how.

I would have also suggested TC... But they're all Chinese made now... Anyways, what tuning were you loOking for in particular? I'd say the largest box you can fit with lots of port.. I'd suggest around 32-35hz tuning, but it's all personal Preference.

All tread is best for bracing IMO.. Bracing raises scores. No doubt.

Two main options, get step-downs to step-down the voltage to all of your 12v accessories, or run a stock and externally regulated output alternator, as said above since your running at a higher voltage there is less current pulled and more watts produced. In most cAses lArger amplifiers like the saz- series from sundown will run to 18v BUT most normal multichannel amps are around 15v max.

I literally loled

They're done mang! You just gotta bondo that shit up! Ill hit you up soon.

lawdy lawdy lawdy it's nearly 11 in MO and no one is on!

:ehh:

Install is 1000000% of the sound.

Crazy

Going from 5-10 MPH to a dead stop = tons of damage.

Pic = Unrelated.

TOP!

Slowhop

^^ JW, is this a standard? Because I know a few companies try to point out that they exceed the "standard" thread count or what not, JW is this is just a marketing scheme or not? I"ve seen companies like RF do this with their wiring packages. Standard.. Strand count is directly related to flexibility and nothing else... IIRC the "Skin effect" ONLY affects AC current, only. Marketing Scheme at it's best! Welding cable has plenty of strands and is quite flexible... that's 2/0 and plenty flexible

Very true, I'd own an '06 M5 in a heartbeat.. But I can't remember which year had bad problems.. i think it was the '06's can't recall though... large trunk + Fast = <3

This^^ ... Also, you might be happy with some SSDs as well... Are you porting or sealing the enclosure?? That will make a difference as well... i was thinking sealed(listen to electro and rap, yah...) but might try ported with a more sq orientated sub? thats y i was thinking the Fi Q, might do some JLs 6s if my friend lets get them ( 2 10s, was thinking about trading my BLs for these since he wants to get an escalade) maybe some pioneers since i can probably get some cheap off of ebay or something. Porting using Aeroports will allow you to sacrifice less space.. also you could easily get the BL's reconed to 12's even 10's for around 100 bucks each + shipping.. Which is indeed CHEAPER then buying all new woofers.