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  • Faital Pro "fake" sensitivity rating?

    Hi guys,

    At the suggestion of a few members, I have been checking out the Faital Pro line of drivers. I have found that the several drivers I have imported specs into Bassbox Pro for simulation have very different sensitivity ratings than what is advertised on the driver's spec sheet as posted at PE.
    One in particular interested me...the 3FE25 16 ohm. So I loaded the specs......triple checked everything to make sure I hadn't entered something wrong. I typically enter the usual qes, qms, fs, cms, xmax, re of coil, le of coil, rated rms power, then I use the "calculate" buttons on the missing parameters. Once I did this, I noticed that the spec-sheet stated 90dB 1watt/1meter didn't calculate out as such....but more like 83.77dB......2.83 volt/1meter is calculated as 81.9dB. The calculated sd is spot on, as is the calculated qts.
    So what the heck? Did the same thing for the 3FE25 8 ohm.....same thing.....differing sensitivity calculation.....about 6+dB short of the spec-sheet listed sensitivity. Even the 5FE120 is not 88dB at 1watt/1meter....it is 86.2dB...which is closer to advertised.
    Well, I was very interested at first in these little drivers and the seemingly higher sensitivity, along with nice value price. But after looking closer, while they might deliver a really flat response through their working range, I cannot call them a real value in my mind. Where I thought to use dual 16 ohm units in a little MTM configuration with a small tweeter, and get a nice sensitivity, I find that with the calculated specs based on above data, I would need 4 of these buggers in parallel to get anywhere near what I initially thought I could based on stated specs. What a bummer. But why such a difference in the sensitivity? How are they coming up with this 90dB rating when clearly, they are not going to be anywhere near that?

    John
    Last edited by johnnail; 11-03-2015, 09:52 AM. Reason: More data
    If it doesn't fit right the first time, you obviously need to use a larger hammer. :p

  • #2
    Re: Faital Pro "fake" sensitivity rating?

    Yeah they are being a little optimistic with their ratings. The BassBox calculations are correct. It is really difficult to make a small driver with high efficiency so any time you see a 3" driver claiming 90dB efficiency it probably isn't true. One of the best drivers I've found for this application is the Tang Band W4-1320, which has a legitimate 88db efficiency rating. Granted, it's a 4" driver with a 5" frame, but a pair of them would make for a nice high efficiency midrange section.

    Dan
    _____________________________
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    • #3
      Re: Faital Pro "fake" sensitivity rating?

      I wonder how realistic the sensitivity is on these guys. http://www.parts-express.com/grs-4fr...8-ohm--292-434

      Comment


      • #4
        Re: Faital Pro "fake" sensitivity rating?

        Originally posted by johnnail View Post
        Hi guys,

        At the suggestion of a few members, I have been checking out the Faital Pro line of drivers. I have found that the several drivers I have imported specs into Bassbox Pro for simulation have very different sensitivity ratings than what is advertised on the driver's spec sheet as posted at PE.
        One in particular interested me...the 3FE25 16 ohm. So I loaded the specs......triple checked everything to make sure I hadn't entered something wrong. I typically enter the usual qes, qms, fs, cms, xmax, re of coil, le of coil, rated rms power, then I use the "calculate" buttons on the missing parameters. Once I did this, I noticed that the spec-sheet stated 90dB 1watt/1meter didn't calculate out as such....but more like 83.77dB......2.83 volt/1meter is calculated as 81.9dB. The calculated sd is spot on, as is the calculated qts.
        So what the heck? Did the same thing for the 3FE25 8 ohm.....same thing.....differing sensitivity calculation.....about 6+dB short of the spec-sheet listed sensitivity. Even the 5FE120 is not 88dB at 1watt/1meter....it is 86.2dB...which is closer to advertised.
        Well, I was very interested at first in these little drivers and the seemingly higher sensitivity, along with nice value price. But after looking closer, while they might deliver a really flat response through their working range, I cannot call them a real value in my mind. Where I thought to use dual 16 ohm units in a little MTM configuration with a small tweeter, and get a nice sensitivity, I find that with the calculated specs based on above data, I would need 4 of these buggers in parallel to get anywhere near what I initially thought I could based on stated specs. What a bummer. But why such a difference in the sensitivity? How are they coming up with this 90dB rating when clearly, they are not going to be anywhere near that?

        John
        Calculated sensitivity is a very general value, which I believe assumes a perfect piston as it's based on T/S alone, so my recommendation would be to use calculated sensitivity from T/S as a guideline only. Now that's not to say manufacturers's don't inflate their numbers. Depending on the manufacturer, you may see peak sensitivity, or sensitivity at 1kHz, or peak sensitivity over a specific frequency band. Not often is it listed as average sensitivity over the driver's intended range, as the higher peak value promotes more sales, especially if the competition is doing the same. The problem here is that when designing using a particular driver, minimum sensitivity is of greater importance to me than the peaks.

        Looking at the Faital drivers you mention, if you refer to the frequency response, the listed sensitivity appears to be listed as peak sensitivity below 5kHz. Refer to the frequency response, or measure frequency response yourself to determine the sensitivity over the frequency range in which you intend to use the driver. Since the sensitivity is rated equal for both the 16 ohm and 8 ohm models, I would assume that it is in fact a 1W/1m rating, not 2.83V.

        Now if you want "fake" sensitivity rating, look up the datasheet on a Infinity Reference subwoofer.
        "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
        exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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        • #5
          Re: Faital Pro "fake" sensitivity rating?

          Originally posted by generic View Post
          I wonder how realistic the sensitivity is on these guys. http://www.parts-express.com/grs-4fr...8-ohm--292-434
          Those are very sensitive, and likely accurate. Rory was pretty proud of those....

          Another that is legit is the PRV 4MR60-4.

          Of course, all get a 6dB loss if used as a woofer, due to BSC.

          Later,
          Wolf
          "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
          "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
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          • #6
            Re: Faital Pro "fake" sensitivity rating?

            Originally posted by johnnail View Post
            Hi guys,

            At the suggestion of a few members, I have been checking out the Faital Pro line of drivers. I have found that the several drivers I have imported specs into Bassbox Pro for simulation have very different sensitivity ratings than what is advertised on the driver's spec sheet as posted at PE.........

            John

            You are exactly right. I purchased a pair of the 8 Ohm version + 1 1/2 years ago. While I liked the driver a lot, I posted a review pointing out that the sensitivity rating is B.S. The review was posted, but now I see it is gone.

            I am rather disapponted and can't believe that PE would stoop so low as to remove a negative review!

            In spite of the fake sensitivity rating, IMO those 3FE25's are great little, clear sounding drivers and I would not hesitate to use them again. They actually sounded more sensitive than they calculate out to be, perhaps because of the clarity of the sound. Like I said, I did like them a lot. Try them out. I think you will like them.
            “I cried because I had no shoes until I met a man who had no feet”

            If we all did the things we are capable of doing, we would literally ASTOUND ourselves - Thomas A. Edison

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            • #7
              Re: Faital Pro "fake" sensitivity rating?

              What is often not understood is that T/S parameters define a driver's behavior at resonance; this includes the calculated sensitivity. It is the sensitivity at the resonance frequency. A driver may have significantly higher sensitivity in its midband. If the manufacturer assumes the driver will be used primarily in that range it may rate the sensitivity based on the frequency response and the primary range they believe it will be used in. This isn't really being deceptive.
              Click here for Jeff Bagby's Loudspeaker Design Software

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              • #8
                Re: Faital Pro "fake" sensitivity rating?

                Also for any driver make sure you are looking at a sensitivity spec (at 2.83Vrms) and not an efficiency spec (at sqrt (Z) Vrms). I notice that vendors often mix them up, likely due to them not assigning the task of writing of spec sheets to their most technically valuable staff!
                Free & Free-form simulator/designer for Passive Crossovers
                SynergyCalc 5: design spreadsheet for Wooden horns and DIY Synergy Waveguides
                Super easy and cheap to make high performance sound diffusers

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                • #9
                  Re: Faital Pro "fake" sensitivity rating?

                  Originally posted by Jeff B. View Post
                  What is often not understood is that T/S parameters define a driver's behavior at resonance; this includes the calculated sensitivity. It is the sensitivity at the resonance frequency. A driver may have significantly higher sensitivity in its midband. If the manufacturer assumes the driver will be used primarily in that range it may rate the sensitivity based on the frequency response and the primary range they believe it will be used in. This isn't really being deceptive.
                  No, that is not correct. The T&S parameters also define the passband efficiency in the pistonic range,
                  and in fact driver efficiency and sensitivity reference the passband, not at resonance. Read the original
                  paper, page 275 in the paper equation 11 on that page:
                  http://www.readresearch.co.uk/thiele..._article_1.pdf

                  Small writes:
                  "The system response function G(s) contains complete information about the amplitude and phase
                  versus frequency responses and the transient response of the system. G(s) is always a high pass
                  function with a value of unity in the passband. Thus the constant part of Eq(11) is the system
                  passband efficiency."

                  Don't even try to spin it.

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                  • #10
                    Re: Faital Pro "fake" sensitivity rating?

                    No... I guess not. But if they don't state that it is based on one thing and not the other.....it leaves the purchaser with the old "I had a broke watch that was right twice a day" feeling. I have so far read of 3 possible areas that any driver can be rated for sensitivity.....region of fs, averaged working band, or peak within working band. Seems like there are no standards......everyone rating them in the same way.....would be nice.

                    John
                    If it doesn't fit right the first time, you obviously need to use a larger hammer. :p

                    Comment


                    • #11
                      Re: Faital Pro "fake" sensitivity rating?

                      No it is always passband - period. Or show me one manufacturer that states it is at resonance Fs.
                      We are supposed to figure out the shape around cutoff with a simulator.

                      They may use some other hand waving to inflate their numbers.

                      It is marketing BS when they are way off, or an honest error.

                      Peaks due to breakup don't count and the T&S analysis doesn't predict that.

                      A company may choose to measure the driver and then rate it at the highest peak,
                      but people catch on to that and then do not trust the numbers. I always put the
                      T&S numbers into a simulator, as you did, just to get a sanity check on their
                      published numbers.

                      This seems odd because Faital Pro seems to make a quality product and seems to
                      be very professional, not sure what is going on there. Some companies are right on
                      the numbers as far as this goes and others I never trust.

                      Sometimes I think what happens is that they make the data sheet for the 16 ohm
                      version by editing the 8 or 4 ohm version and then forget to change some of the
                      numbers, just throwing it out there as a possibility.

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                      • #12
                        Re: Faital Pro "fake" sensitivity rating?

                        Originally posted by Pete Basel View Post
                        No, that is not correct. The T&S parameters also define the passband efficiency in the pistonic range,
                        and in fact driver efficiency and sensitivity reference the passband, not at resonance. Read the original
                        paper, page 275 in the paper equation 11 on that page:
                        http://www.readresearch.co.uk/thiele..._article_1.pdf

                        Small writes:
                        "The system response function G(s) contains complete information about the amplitude and phase
                        versus frequency responses and the transient response of the system. G(s) is always a high pass
                        function with a value of unity in the passband. Thus the constant part of Eq(11) is the system
                        passband efficiency."

                        Don't even try to spin it.
                        You are correct. I was referring to the fact that some drivers have a rising response in their upper range that is higher than their reference sensitivity. I think you would refer to that as a non-pistonic region. I characterized the reference sensitivity incorrectly, sorry about that.
                        Click here for Jeff Bagby's Loudspeaker Design Software

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                        • #13
                          Re: Faital Pro "fake" sensitivity rating?

                          Bassbox Pro calculates the GRS 4" Pioneer replacement at 87dB

                          John
                          Last edited by johnnail; 11-03-2015, 10:39 PM. Reason: incomplete
                          If it doesn't fit right the first time, you obviously need to use a larger hammer. :p

                          Comment


                          • #14
                            Re: Faital Pro "fake" sensitivity rating?

                            You misread my posting and overthink it. I did NOT state that it was any manufacturer...I was referring to other posts in this thread.

                            John
                            If it doesn't fit right the first time, you obviously need to use a larger hammer. :p

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                            • #15
                              Re: Faital Pro "fake" sensitivity rating?

                              The 5FE120 calculates out at 86dB...which is only about 2dB shy of spec stated. But several of the others are off by more. As for 16 ohm versus 8 ohm of the other driver.....the 8 ohm version is also overstated.....91dB....I calculate it at 84.7dB

                              John
                              If it doesn't fit right the first time, you obviously need to use a larger hammer. :p

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