95Honda

Again, there is no skin effect in DC, so litz wire is useless. The only place you will see litz wiring in car audio is the transformers in your amp's power supply. Why? Because you are dealing with frequencies that are much higher than the audio band and there is great skin effect.... Most amps switch well over 40 Khz...

The whole "increased surface area" isn't just marketing BS, but a straight up lie..... In the DC realm Awg = Awg as far as current capacity w/the same type of conductor material.... Stranding makes no difference whatsoever... Welding cable.

I hope this isn't directed at me.....

I did come to a conclusion, you just didn't realize it. If anyone tries to explain SQ based on the parameters you listed, they are well, wrong.

^Pretty much agree with this and need to point a few other things out. The parameters you listed have no bearing on sound quality. At all. The parameters you need to take into consideration when trying to figure out if a driver will have low distortion are not normally published along with many car audio drivers, with the exception of Le, and in some cases Bl curve. What you really need to know if you are going to determain driver sound quality (low distortion) is a measurement of exactly that, distortion. You will want to see what type of harmonics the driver produces, non-linear behavior and Fr adnormalities. But again, most manufacturers don't publish this data, they normally just tout the features they have that combat this. Now as far as determaining sound quality from basic T/S parameters as you posted, you will be able to predict the type of response you will get (ripple, group delay, Fr, etc) based on enclosure Q and you will know when the driver should start behaving non-linearly due to linear excursion limits.... But that is about it. And the sound quality of the chosen alignment is also very subjective. In all reality, a flat alignment with minimal ripple often sounds thin to most people, even though it is probably the most accurate alignment the driver will perform in... So really, nobody can answer your question with your parameters with anything more than heresay. Oh yeah, I have probably built 300 or so enclosures, "out in the shop"

Just FYI, if you mount the driver with the magnet out you will hear the maximum amount of mechanical noise..... But, I haven't ever heard of this to be an issue with your drivers, so it is probably won't even be discernable at most...

I think you will be happy anywhere between 2-3 ft3. Another nice thing about sealed boxes is that they are very forgiving as far as miss-alignments... Personally, I would put it in a 2ft3 ish box with no fill.... The only type of dampening I use in a sealed box that already has a target Q is to line the walls with an inch or so of fiberglass for the sole reason of cutting down distortion caused by mechanical driver noise/upper harmonics...

Strand count has nothing to do with DC since there is no skin effect and the current travels through the entire conductor. This is a huge, huge missunderstanding in the car audio community. There is no such thing as copper tinned copper. Normal copper that is tinned with anything only helps with oxidation in the DC realm. (again, no skin effect in DC so higher conductivity tinning has miniscule effect) Aluminum wire of the same gauge is a much worse conductor than copper, no matter what the aluminum is plated with. That is pretty much the end all and can't really be disputed. Period.

I don't know what the T/S parameters are, but if that box gives a Q of around .7 or less than polyfill won't make things any better. May even sound worse to alot of people....

Are you sealing off everything into the cabin except the port? Or are the port and drivers firing into the cabin?

Distortion is anything other than the original signal. It is as simple as that. The biggest forms of distortion in car audio come from overdriven amplification stages (clipping) frequency shaping (Eq) thermal noise (hiss) RFI/EMI (ignition noise) and AC components getting in the signal chain (alternator whine). This is not an inclusive list, and not in order. The "-40db" you ask about is pretty simple. db is a logarithmic scale. 40db is roughly 10,000 to 1 as a ratio. Put into simple terms, if you had an amplifier that was putting out 10,000 watts and it had a distortion content of -40db or lower it would be putting out 1 watt or less of distortion at full output. -40db is very low, you would never hear this in a car. Most, and I say most because I mean the average guy banging down the street, probably wouldn't notice anything under -20 or so below the fundemental....

I guess my issue with a product like this, and all the other tutorials I often see on the web with gain setting/clipping are really a waste (imo) because they place people into a false sense of security because they aren't clipping thier amplifiers. When in reality, the clipping doesn't hurt anything, it is the simple overpowering that ends up cooking a voicecoil... I know, this will get debated endlessly, but I have done my own objective tests on this, published them on the web and stand by them. I think having a distortion indication of some kind is great, but honestly what purpose does it serve to show when distortion levels are present if you can't hear it with your ears? I think this is the root of the problem... Additionally, -40db below is ridiculously low as far as power problems are concerned. Again, great to know, but for what purpose? I have been building amplifiers for over 17 years, I only say this out of experience...

Waste of money, especially since clipping doesn't hurt anything... This is comparable to buying a "Shake Weight" and thinking it will make you look like the guy on the box...

No problem...

The impedance curve is just that, an impedance curve. Modeling programs normally predict at small signal levels (a watt or so) and they do change as power increases. They can vary in form, but overall they normally increase overall when thermal effects set in. The main peaks above and below the tuning trough will also shift if the thermal changes and other factors start affecting driver Q. So I guess the answer to your question is yes and slightly no. I didn't get a chance to read your link, but from what you typed then yes, you were measuring impedance (not resistance). Resistance is not relevent to loudspeakers as they are a reactive load. Every off the shelf clamp will be different. Most will be OK in the bottom few octaves of the audio spectrum. The only way to prove if your clamp meter is accurate is to compare it to a calibrated current sensor, I have one, but it cost almost $1000. -OR- just don't worry about the few % you will get in error. You could also email the manufacturer of your particular clamp and see if they have a generic calibration graph for your particular model, if they do, you could factor that into your equations.

I think where people get confused on this is what is actually happening with the port in respect to the enclosure. The port is the primary contributor to system resonance in a 4th order vented alignment. The size of the enclosure and the area of the vent are really not included in this basic foundation. Case in point. If you take an 8 cubic foot enclosure with a single 3" I.D. vent that is appropriately tuned for a desired resonance it works perfectly well. How do I know this? I have placed a Focal 8V4412 in this exact box and performed measurements using IMP, 15 years ago. The vent had the predicted resonance, the impedance peaks were where they were suppose to be and there weren't any erroneous driver behaviors. This is with an enclosure thas had roughly less than 1 square inch of vent area per cubic foot. Why did this work well? It was an 8 inch driver with roughly 7mm of 1-way throw being driven with 50 watts... On the other hand, I have used 6" I.D. vents in 1 cubic foot boxes and they also behaved as predicted. I was doing some early designs with assisted 4th order alignments and a 1st generation Adire Brahma 12" subwoofer. Using a rane parametric EQ and trying to run the driver flat down to 20 Hz in a box this size required all of it's excursion at even moderate listening levels. This require a large amount of vent area to stay away from compression. The vent in this case was very long, all of it was outside the box. But is still behaved as a vent, the cone was heavily dampened at resonance and the impedance was where it should be. This was with an enclosure that had roughly 25 square inches of vent area per cubic foot of enclosure volume. What is the point of these 2 paragraphs? Vent area has nothing to do with the enclosure size, but everything to do with the driver and power used. But again, this goes down to the basic foundation of this concept. I am not arm-chair quaterbacking this either, these are real world scenarios I have actually conducted myself. That is all I am going to offer on this subject.

What I was eluding to about the clamp meter is decent ones will read OK in your range. For power of a sine wave (and only a sine wave) You only have to multiple RMS Voltage by RMS current to get RMS wattage. Simple as that. Even if you use an oscilliscope you still need a current pickup to take a reading... And remember, most oscilliscopes only read Pk-Pk or Pk voltage, and unless they have a built in calculator, you have to do the math to get RMS values.... And if you are using a current probe, you will have to pay close attention to current vs. voltage representation and be sure you check if it has differing levels at different frequencies...

To be honest, as far as clamp meters, they should be accurate between 50-400Hz.... As this is the most common range of AC power measurement. The Flukes we have at work get calibrated yearly, and they are within a 1% or so in that range, and these are the ones that aren't very expensive. I sometimes conduct EMP hardness testing and use very high current rating inductive pickups to measure high power content pulses. These are devices that cost several thousand dollars. When I conducted my clipping effect tests a while ago I used both the high current inductive probes and a standard Fluke clamp and didn't see much of a difference with sine wave measurements in the bottom few octaves of the audio realm. When I was dealing with square waves, I couldn't use the Fluke clamps because I needed a visual indication of real time current on an oscilliscope, and this obviously wasn't possible. Now if you buy a $20 Velleman kit clamp meter off of e-bay, I wouldn't trust it's accuracy at any frequency...

There are 2 major factors that I think will kind of help explain what you are asking(?)... Normally, in a vented 4th order alignment (which is most of what we discuss on here) you are going to have 3 impedance peaks. The first 2, which will be domiant for most of our applications, are the peaks below and above the dip (trough) at tuning. The 3rd peak, and not quite as signifigant (or completely ignorable if you are totally out of the bandwidth) is the gradual peak that is caused by the inherent inductance of the voice coil. So, an easy way to describe the first 2 peaks.... At resonance, the cone of the subwoofer is highly damped by the entire system attributes (mainly the Hemolitz resonation taking the load from the cone in an efficent manner) and due to the high amount of dampening (control) the reactive electrical properties are at a low point (null) and load is moved into a more resistive (reactance properties start cancelling each other out) realm... Above and below this point dampening suffers quickly and is immediately apparent due to the high amount of impedance shift... I am not sure if this is broke down well for understanding... I haven't really had to explain this many times and there are alot of people out there who could convey this better than I... The 3rd peak is easy. The voice coil is an inductor, inductive reactance is proprtional to frequency. And a little food for thought, some overhung designs have 4-5mH of inductance, this starts raising impedance signifigantly as low as 100 Hz or so.... This is why I always say there is no such thing as "Impedance Rise".... You can see, the impedance goes up and down alot...

Which peak? (there are normally more than 1) Or do you just mean what happens when impedance goes up?

Just something to remember, the more power you give any sub the worse it performs. Any sub.

The relation of enclosure volume to vent area is not really valid. It can be used as a"rule of thumb", but it isn't correct alot of time. The major factor for vent area is going to be power used, sub efficiency and displacment. Box volume doesn't really factor in... If you really want to know the answer to your question, other than a "rule of thumb" you need to model your design with the expected power you will have a look at the predicted vent velocities. This is the only true way to determain minimum vent area... Every other way is either going to be overkill or a shot in the dark..... And no matter what anyone says, this doesn't matter if it is free space or confined space, it will be the same...

Most amps, class D inclusive, are not most efficient at the lowest rated impedance... In fact, they usually takes a dump at efficiency on the bottom of load tolerance... And dampening goes to hell....

It won't hurt anything at all to have them in seperate boxes.... I (or anyone else for that matter) just won't be able to tell you how they will perform like that. It may work great, or they might have cancellation issues.... Who really knows...

Like said above, they won't really be too good in a 2-way, in fact, they would be horrible sounding in just about any 2 way. You really need a woofer made to go high enough to mate with most horns, and car audio subs usually have way to much inductance and other T/S parameters that don't lend well... You will need to go 3-way with a dedicated midbass to do this right. You also need to look at efficiency, Car audio subs are usually well below the sensitivity levels of pro-audio drivers, this could make integration a challenge...