helotaxi

I'm gonna go out on a limb and guess that the difference in the Xmax is solely for linearity on the Q since it is an SQ oriented driver.

Dependes entirely on the amp. Some won't change power output at all with a drop in input voltage, they will simply draw more current at the lower voltage to make the same power. As far as CEA specs go, IMO worthless for bandwidth limited amps since CEA specs use 1kHz for the rating freq. Most Class D sub amps won't play above 250-300Hz. A 1kHz spec isn't really going to tell you anything there now is it.

To get anything resmebling RMS without using RMS meters, you must use a sine wave. I still question the usefulness, other than repeatability, of fixed load testing. At that point it gets to be like dyno drag racing..."under ideal conditions the amp will do X, under real conditions...well who the hell knows?!?" Even the CEA ratings are pretty bogus considering they are spec'd at 1kHz. What if the amp can't play that high? What freq do they use then? Are the ratings valid at all for a bandwidth limited amp? If you want applicable numbers, you're going to have to do the testing yourself. If you're going to do the testing yourself you may as well use the actual load you plan to drive and the actual power supply you plan to use. IMO that's going to give you the most relevant results.

http://cgi.ebay.com/NEW-COUSTIC-XM6-3WAY-6...1QQcmdZViewItem Not nearly $500...Will do 3k on the top of the midranges.

What do you have your HD-2 crossed at?

That will give you peak output. To get RMS you will need either to use true RMS meters for both voltage and current or multiply the peak value by sqrt(2)/2 ot give a pretty close approximation of RMS.

Hoping you're kidding about the last part but in case you weren't, forget you ever saw that "equation."

Yeah, not sure about the basis of the +10 ref either. The fluid nature of air will keep you from ever getting port velocity in the neighborhood of Mach. As the pressure in the box starts to increase, the air in the port will simply "pack up" the port and the box will start to act like a sealed enclosure with almost no port action. The threshold for this should depend on port area with it happening more readily with smaller ports. You could aleviate some of this with aggressive flaring of the port ends, but that is self defeating because it reduces port speed. Go with at big enough port that packing isn't a issue and you wuold need a huge amount of sub displacement to move enough air to get the port velocity high again and you start running into the same problem as with the small port and it still packs. The long and the short, it isn't going to be possible. Your best bet would be something like a high speed rotor with a wicked servo motor on it and one hell of a gearbox. Even still you're looking at something on the order of 5100RPM for a 3 ft diameter rotor if my math is right for the rotor tip to go supersonic. Then you have to account for aerodynamic effects on the rotor and make it strong enough to keep it from ripping itself apart. You could I guess also try to build a supersonic wind tunnel, but if you've ever seen one of those, they usually take up a fairly large building, several VERY large fans and a tapering vaned duct to accelerate the air without turbulence f'ing the whole thing up.

Have you gotten ahold of the ES-06 or the 06+ or the M6+ yet? Just curious because I'm getting ready to rebuild my front stage and I'm just trying to decide on which of these I want and whether the ES series are worth the close to 2X price difference. How low do you have the HD-2 crossed and at what slope?

P=V*I by definintion. One of the discussions on here previously was whether, since the coil of the driver shifts the phase of the current in relation to the voltage, you could simply multiply RMS voltage by RMS current and get power or if you have to actually account for the phase shift. My take is that since it is the current that is doing the work and the voltage is simply inducing the current IAW Ohm's law, you can simply multiply them out.

Dibs! NEGATIVE!!!!!!!!!!!! I asked about it first!!!! J You asked...I declared! I win!!! been here longer, AND higher post count. By a whole week, and so what...now you're quibbling...it's like calling "shotgun" no other phraseology works for that either.

We have a new convert! Welcome to the tribe of the proper tool for the job!

the cone doens't have to break the speed of sound (and it never will) the air in the port could. But even that is rated unrealistic because the pressures on the cone would simply rip it apart long before the port velocity approaches supersonic. Jim, the speed of sound isn't constant, it varies with temp.

You would def have to mod the Q-forms. Two layers of fiberglass on the inside should stiffen them up nicely. Sealing the back is a plus too.

They make a similar setup with just the mid and tweet without the woofer. They might just fit i my A-pillars...

Don't forget to account for material thickness...

My dad used a "square" displaying the features you described when setting up his radial arm saw back when I was a little squirt. It took him awhile to figure out why everything he tried to build came out f'd up. Then whe he tried to use the "square" for something else and compared it to a real square, the problem dawned on him. That's why I used an engineer's square when I set up my table saw and I recheck it before I start every project. We all are really...

Dibs! NEGATIVE!!!!!!!!!!!! I asked about it first!!!! J You asked...I declared! I win!!!

I've herad complaints about the SQ of the Sirius system, in fact that was why I went with XM myself. If you can hear a difference between my XM setup and my hardwired iPod (everything on it is ripped at 196k) going down the road, I'd be amazed. SQ aside, for me it is worth the couple bucks a month over broadcast radio. There is not a good radio station here at all. There are two I can tolerate but they play more commercials than music. The themed music channels on XM have no commercials. The comedy channel (150) has 3 commercials every 30 min. The couple of Clear Channel supplied feeds have normal comercials but not nearly as often as broadcast radio. The channels I have on memory are: 150 (Comedy) from there its a short tune to 153 (Canadian Comedy) 8 (80's) from there I can get to 90's on 9 quickly as well 41 the Boneyard- all hair bands and 80's and 90's hard rock/heavy metal 66 (and from there 65 and 67) the good hip hop/rap stations 48 - I can't remember what this station calls itself or what its theme is but its always stuff you know I use this one and 41 to get me into the rock section when I'm surfing channels 82 - Dance from here its quick to get to 81 and 80, the other electronica/techno/trance stations I can only handle this stuff in really small doses but it keeps the wife content for a few minutes before I go back to the 80's channel If you road trip a lot SAT radio is a godsend. Try finding any normal radio station in the middle of BFE (AZ or Nevada desert, all of NM, MT, ID, SD, ND, NE, IA, the CO Rockies, the "Gap" (the folks from Canada know what I'm talking about)). Also figure in no adjacent station interference, no static, no fading reception etc... Sorry, you just can't compare SAT radio to regular broadcast. Now you say, "What about HD radio?" Well here's my take on that. The backers of HD radio try to sell it as "'Free.' The way radio should be." The programming might be free but the hardware is big $$$. $350 for a HD tuner!?! Let's break that down compared to XM. I can get an XM tuner for $30. Add a hardwired FM modulator for $50 (you'd have to do the same thing for HD to add it to a factory system or any system that isn't "HD Ready"). Now you pay for close to 2 years of programming to get to the same cost as the "free" HD. And that programming cost is spread out over 2 years instead of all coming out of your pocket at once. Now look at availability. HD isn't broadcast everywhere. XM is available everywhere inside the footprint of the satellite constellation, translation "Norht America." What about programming? With HD you're stuck with the same stuff that comes over normal broadcast radio it just has better sound quality (about the same as satellite, BTW). You might get a repeater of a station in another market, but it still has all the comercials and the same programming as usual. As far as program goes, IMO, you get what you pay for with HD, but the price of admission pretty well kills the deal. Bottom line: if you are looking for something to do critical listening with, SAT radio may not be for you, but then neither is mp3, broadcast radio or even HD radio. If you are looking for something to listen to while you are spending time in your car anywhere in North America that sounds pretty good, SAT radio is probably the way to go.

That's great. I guess you have every song you ever want to listen to on CD then? A good SAT install will sound just as good as an MP3. A CD will sound better than either. If you can tell the difference going down the road, the problem is with your install, not the SAT broadcast.

Who cares about preout voltage?!? I'd rather have some useful features like a sub crossover or some real EQ ability or time alignment (Bass Engine Pro, anyone?). Preout voltage matters so very little that it doesn't even enter into my purchase decision unless everything else is equal on two different unit (including price) and I need a descriminator.

The voltage shouldn't change much. Not enough to account for the change in current. Even with the regulated amps it won't even get you in the ballpark. The only time it would work is in the case where the output current just happened to equal the input voltage i.e 600-700W at 4 ohms, 300-350W @ 2 ohms or 150-175 @ 1 ohm. Get outside these ranges and that equation means nothing. Inside those ranges it's only coincidence.

Agreed on all the subwoofer stuff, but this post was specifically talking about midranges and tweeters and the confusion caused by the ratings when trying to match them in a DIY setup.

Pretty cool, though I think I'll stick to my external processor for all that.

My bank account hurt just reading that... I wish I had the shop space to justify buying even one thing by Festool but sadly my limited shop space is going to go to zero as soon as the Mrs. gets her new car.