Announcement

Collapse
No announcement yet.

Why does PE persist in listing Vas as cubic feet?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Why does PE persist in listing Vas as cubic feet?

    By my search of the TT forum, it has been 4 years since someone whined about this topic. The time has come to whine again.

    Unibox, WinISD, the Bagby Suite, SoundEasy, basically all the tools that I can name, use SI units (liters) for Vas. And even PE themselves list the metric values for the other T/S parameters. Every product page. Sure, yes, the spec sheets list metric, and yes, I can Ctl+T and type ".63 cubic feet to liters". Heck, deliver the Sd in square inches for all I care. It's the inconsistency that drives me bananas. Go imperial or go metric. But don't waffle, folks.
    nothing can stop me now

  • #2
    WinISD allows you to easily change units during entry. That is a nice feature.

    Comment


    • #3
      I'm guessin 'cause none of use "meter-sticks" at the table saw, or when sketching out a new design. I've got WinISD set to cu.ft. and cm^2 for Sd.
      When they start spec'ing Vas in just liters, I'll be the 1st to wail. People (here, in the U.S of America) don't build houses in sq. meters, and we don't drag race on 402.336m tracks.
      Let's be Americans, let's stay with cu.ft. (just sayin')

      Comment


      • #4
        we need to build a wall to keep the liters out, they're some bad hombres

        Comment


        • #5
          Search here on cubic, feet and meters. See post #19:

          http://techtalk.parts-express.com/fo...6-vas-in-cu-ft
          Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

          Comment


          • #6
            Agreed, Dirk. 99% of the spec sheets I read list VAS in Litres, and that includes Dayton. It's time PE and the US on the whole joins the rest of the world and embraces the metric system. It's only been what, 50 years since most everywhere else adopted metric. The US is straggling along with only Burma and Liberia embracing imperial.

            Now everyone repeat after me, "19mm of MDF".
            Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

            Comment


            • #7
              Originally posted by neildavis View Post
              Search on cubic, feet and meters. See post #19:

              http://techtalk.parts-express.com/fo...6-vas-in-cu-ft
              I did. But like I said, it's been 4 years. As far as I'm concerned this is a matter deserving of fresh indignancy.

              I don't have a problem with Imperial measurements. I like my gallons and inches. My beef is with the inconsistency. Use inches & gallons or meters & liters, but never mix the two in the same document. That's just bad form that leads to the accumulation of errors.
              nothing can stop me now

              Comment


              • #8
                Originally posted by dirk View Post
                this is a matter deserving of fresh indignancy.
                lol

                John H

                Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

                Comment


                • #9
                  Tl;dr, this is PE's stance from 2013:
                  This is a discussion that gets had around here every now and then. It boils down to how PE's customers look at the specification data on the product page to make a buying decision, and how the data provided can best facilitate that buying decision. The view is that by using units that are the cube of a linear unit (e.g. cubic feet, cubic cm), customers that like to "guess at" the necessary size of the enclosure will be able to most easily envision the enclosure size in terms of its linear dimensions. (I believe this is why so many subwoofer enclosures end up being perfect cubes, even though I don't think the cube is a very aesthetically appealing shape unless it's very small.)

                  The objection from proponents of providing the value in liters is that these "guesses" at the necessary enclosure volume for a certain driver are usually not very accurate, and that's true, but many of my vented boxes end up very close to Vas in volume or a little less than that, tuned very close to Fs, and the "acoustic suspension" and "infinite baffle" alignments of sealed boxes are expressed in terms of Vas/3 or Vas*3 respectively, so Vas does have some predictive value. For that reason, I think that if it were up to me, even if we did standardize on SI units at PE, I'd lobby to have Vas expressed as cubic centimeters, and not liters. It's more difficult to imagine the physical "size" of a liter of air volume, and if I were to go through the exercise of trying to explain to someone how "big" a liter of air is, I would still intuitively resort to describing the size occupied by that volume in terms of cubic linear units.

                  For those who must have liters, the Dayton Audio spec sheets already provide the value of Vas in liters (not cubic feet) for your box modeling convenience, because it is a 'de facto' standard among box modeling programs to use liters. As for providing Vas in cubic feet and liters, that may be something to explore further.

                  Just for reference, a liter of air volume occupies a cubic volume of 1000 cubic centimeters (1 cc = 1 ml), having dimensions of 10 cm on each side, and you can convert from cubic feet to liters by dividing the number of cubic feet by 28.3 (or multiplying by .035, whichever is easier for you to remember).
                  As far as I'm concerned, it boils down to the same discussion that happens every time someone want to discuss a change from imperial to metric. A bunch of people will say gee why haven't we changed everything to metric yet, and a bunch of others will complain "I don't like change, what the heck is a litre anyway?". I doubt anything will change anytime soon.
                  Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

                  Comment


                  • #10
                    Originally posted by dcibel View Post
                    I doubt anything will change anytime soon.
                    If you're working on an American car built since roughly 1990 you're using metric wrenches. You can buy a gallon of milk, but you have to buy a liter of Coke, or 750ml of wine or liquor. The switch is coming along, slowly, but surely. We're not all that backwards, in the UK and Ireland people still state their body weight in stone.

                    www.billfitzmaurice.com
                    www.billfitzmaurice.info/forum

                    Comment


                    • #11
                      Originally posted by billfitzmaurice View Post
                      If you're working on an American car built since roughly 1990 you're using metric wrenches. You can buy a gallon of milk, but you have to buy a liter of Coke, or 750ml of wine or liquor. The switch is coming along, slowly, but surely. We're not all that backwards, in the UK and Ireland people still state their body weight in stone.
                      Are those imperial gallons, or US gallons? That one is the worst for anyone looking at a homebrew recipe and it just says "gallons".

                      In Canada we buy milk in litres, which may be why I find it easy to judge volume in litres, instead of cubic feet. I just think of how many milk cartons I could stack to fill the volume. I don't measure anything in cubic feet, it's either litres or cubic meters.
                      Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

                      Comment


                      • #12
                        Well,not so much speakers but I would not want to frame out a house in metric or buy a 4'x8' sheet of ply in metric although the thickness maybe 19 mm. Old dogs
                        you know.

                        Comment


                        • #13
                          Different spec sheets (e.g. one from PE, the other from Dayton Audio) for the same Dayton driver can have both measurements, which is a bit confusing.

                          While metrics are used by most of the world, including Australia, imperial measurements are still used in industries such as aviation: "knots"," thousand of feet", etc; so there will probably never be absolute consistency in measurement systems.

                          And the Jasper Circle Jig is calibrated in inches, which makes using most brands of drivers a little imprecise, although not as imprecise as my workmanship.

                          But it can get tiresome and confusing having to keep multiplying and dividing by 2.54.

                          Geoff

                          Comment


                          • #14
                            Well, in my current build, I used both inches and millimeters for cutting wood (not at the same time for the same cut); using millimeters gave me the best accuracy on a couple of cuts. And, my drawings for this design also used both inches and millimeters. It doesn't bother me in the least which measurement system is used, although I think and visualize in inches, feet, yards, etc.
                            Paul

                            Originally posted by Chris Roemer View Post
                            I'm guessin 'cause none of use "meter-sticks" at the table saw, or when sketching out a new design. I've got WinISD set to cu.ft. and cm^2 for Sd.
                            When they start spec'ing Vas in just liters, I'll be the 1st to wail. People (here, in the U.S of America) don't build houses in sq. meters, and we don't drag race on 402.336m tracks.
                            Let's be Americans, let's stay with cu.ft. (just sayin')

                            Comment


                            • #15
                              Inches, Feet, Yards, Miles all from the oldest measuring system that gave us hours, minutes and seconds.

                              The inch is the width of the thumb. The foot is obvious. "Man is the measure of all things" is literally true. It was the inch, foot, cubit that built and measured the first civilizations. It was a counting system based on 12 that gave us timekeeping in its unaltered state for 7000 years and counting. The same divisions for clocks is applied to geometry as well. With the inch, ancient man was able to calculate the circumference of the earth, which allowed him to calculate the distance to and the size of, the sun and ultimately, the size of the universe.

                              Someone needs to keep the imperial system, for posterity's sake.
                              R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

                              Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


                              95% of Climate Models Agree: The Observations Must be Wrong
                              Gravity is an overrated force on the cosmic scale. Physicists are missing the bigger picture. They fell into a black hole and were never seen advancing the understanding of the cosmos again.

                              Comment

                              Working...
                              X