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  • ZaphMeister article hit a nerve.....

    Provided Link: ZaphMeister Writeup


    But a good one. He's right you know! I'm living proof. I had been listening with a 15db null and couldn't tell that something was wrong. Just a bit muffled. Measured it and it was like wow, what an idiot I am. Had it reveresed. Put it right and listened to that. Sure enough, it opened up and brighter. So that null was tricking me into thinking that it sounded right when in reality it wasn't. Even a 6db difference is hard to tell IMHO. It's not just ears, it's measurements that get you the results you need in a speaker. I've found that meas., listening, modeling, changing, and doing it all over again and again until you get a good FR line and phase and impedance. Then listen and fine tweak until you get the voicing right. No one ever said it was easy, but doing it by ear is just plain silly. You may get lucky once unless your like Wolf and I bet he would have a hard time gettting it right. Anyway, interesting reading Zaph dude! Keep it up.

    Paul

  • #2
    Re: ZaphMeister article hit a nerve.....


    >>I had been listening with a 15db null and
    >>couldn't tell that something was wrong.
    >>Just a bit muffled.

    I don't understand how it was "a bit muffled"
    and "couldn't tell that something was wrong".

    Didn't the muffled part 'red flag' that something
    was wrong?

    hee hee harr harr


    Comment


    • #3
      Re: ZaphMeister article hit a nerve.....


      Ya it did. That's why I did that in room. Something wasn't right I could tell but where lies the problem is deciphered from the meas. har har har

      Paul

      Comment


      • #4
        Re: ZaphMeister article hit a nerve.....


        > But a good one. He's right you know! I'm
        > living proof. I had been listening with a
        > 15db null and couldn't tell that something
        > was wrong. Just a bit muffled. Measured it
        > and it was like wow, what an idiot I am. Had
        > it reveresed. Put it right and listened to
        > that. Sure enough, it opened up and
        > brighter. So that null was tricking me into
        > thinking that it sounded right when in
        > reality it wasn't. Even a 6db difference is
        > hard to tell IMHO. It's not just ears, it's
        > measurements that get you the results you
        > need in a speaker. I've found that meas.,
        > listening, modeling, changing, and doing it
        > all over again and again until you get a
        > good FR line and phase and impedance. Then
        > listen and fine tweak until you get the
        > voicing right. No one ever said it was easy,
        > but doing it by ear is just plain silly. You
        > may get lucky once unless your like Wolf and
        > I bet he would have a hard time gettting it
        > right. Anyway, interesting reading Zaph
        > dude! Keep it up.

        > Paul

        Don't forget Paul, that if someone uses drivers that have test data available that can be trusted (like Zaph) then they can take a very educated stab at putting together a system that pleases and can be confident in it's objective performance. Guys like you, Zaph, Roman, who've posted their design processes including modeling, have shown that given good curves, you can very accurately model the outcome of the final system.

        It all starts with good data, and I really trust Zaph's methodology. I also appreciate his rationality. Some may find it to be a bit "puffy" but that rationality exudes a confidence borne of knowledge and logic.

        My subjective take on that blog entry: This was my favorite part.

        "Where subjectivity actually works

        During the driver evaluation process, any sort of subjectivity is a bad idea. But on the other hand, subjectivity during the system evaluation process is going to be required. At some point, a designer has to decide on tradeoffs. That could mean deciding what types of distortion are more annoying to the designer personally. For example, what sounds worse: a broad, large increase in even order harmonic distortion in the lower midrange and bass or sharper but narrow band odd order harmonic distortion in the upper treble? Sound familiar? It's the old metal vs paper cone debate and it comes down to personal preference. The choice is a subjective one. Some prefer metal cones while many others prefer paper or poly. That's OK. Measurements can tell the truth about a driver but remember that they can't tell you what you like.

        When a proponent of subjectivity repeats what I just mentioned above, I'm not going to dispute it. Many things in the end come down to personal preference. A system design decision can be subjective, but testing and evaluating drivers individually must remain objective."

        --- Measurements can tell the truth about a driver but remember that they can't tell you what you like. ---


        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
        "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

        Comment


        • #5
          Re: ZaphMeister article hit a nerve.....


          > Ya it did. That's why I did that in room.
          > Something wasn't right I could tell but
          > where lies the problem is deciphered from
          > the meas. har har har

          > Paul

          And as Zaph pointed out, that skill is acquired with time. It probably would have been obvious with a slow swept sine though.
          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
          "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

          Comment


          • #6
            I Hate To Say This


            I used to sell audio. In those days, I found countless numbers of people with their speakers hooked up out of phase, stolidly listening to them.

            Not only that, but I found audio store after audio store with the same problem. Selling audio equipment everyday, with no awareness there was a problem. Boggles the mind.

            However, I never an out of phase connenction at a high end salon.

            Whenever I fixed the out of phase connection, most people were so amazed, they pronounced me some sort of a demi-god. As one guy gushed: "How the hell did you make my system sound so good?"

            People thought that the sound they were getting was supposed to be that way, if they detected it at all.

            If I may pat myself on the back, I can tell an out of phase connection immediately. One commercial speaker, the Infinity Quantum Line Source, chosen briefly as "Class A" by The Absolute Sound, had a really messed up lower midrange that, at most listening angles, always sounded like a driver was out of phase. Luckily, Infinity got better.

            Comment


            • #7
              Re: ZaphMeister article hit a nerve.....


              You
              > may get lucky once unless your like Wolf and
              > I bet he would have a hard time gettting it
              > right.

              Hey!! I resemble that remark! I tell you what, I looked at the curves for the Audinum's drive units, made a best-guess(that's right- NO MODELLING!), and am very happy with the results. =-) There is a little midbass valley. It could've been BSC'd better I suppose, but the level before roll-off is back at nominal, so it's a moot issue. It's not the first time I've done it that way. If it sounds "off", I usually find it in a couple days of listening to different material. It has to do with emphasis in the FR spectrum, about which will tell the story, but I usually find if there is an anomaly present. Locating it? Not always possible. Normally it's solved with stuffing density, polarity of drivers for the best setup. Sometimes it's tuning.
              Later,
              Wolf
              "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
              "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
              "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
              "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

              *InDIYana event website*

              Photobucket pages:
              http://photobucket.com/Wolf-Speakers_and_more

              My blog/writeups/thoughts here at PE:
              http://techtalk.parts-express.com/blog.php?u=4102

              Comment


              • #8
                Re: Some of my thoughts on this.


                I read the article you linked and agree with what was said. Speakers can not be accurately evaluated subjectively apart from the system. Within the system subjective adjustments are what we call "voicing".

                However, it has been my observation that what we hear and the measurements we take may not always match up well.

                All measurements are taken on some axis. Listening, on the other hand, may not be on this same axis, or may be on many different axes. Also we tend to sit further from our speakers then when our measurements were taken. This does two things; changes the path lengths, and alters the balance of first arrival and reflected sound. The more of the power response that falls into this balance, the less a particular axial response matters. I'm not saying that it doesn't matter, only that it's balance shifts.

                As path lengths change so does the phase relationship between drivers and consequently, so does their acoustic summation on that particular axis. Nit-picking to get perfect phase alignment on one axis is a bit like straining on a gnat while swallowing a camel if other axial responses are not being included in the model. For example, in a two-way speaker changing the polarity on the tweeter and getting a 40 dB null, did not really change the frequency response of the speaker (at least it wouldn't if the drivers were not so directive). It simply changed the axis that this null laid on. The null was there all along, just on another axis. Of course, this example is too simplistic, and other factors exist that does make the on-axis response important, but my point is that the power response remained unchanged by this polarity flip, and the more of the power response balance you hear when you listen the less noticeable this null will be.

                Paul, you were talking about baffle step compensation and so forth, but then posted a response that showed a 7 dB rise from the midrange to the lower treble. When you changed the polarity on your midrange you were probably compensating for this rise as you heard it at your listening position. However, when you did so you threw out all of that work to get your "perfect" phase alignment. You also changed the summation in complex ways because the midrange in a three-way is summing with the woofer and the tweeter, while the woofer and tweeter also sum acoustically with each other too.

                Over the years I developed a method of measuring the sound of a speaker that seemed to match up the best to what I was hearing. I thought I was the only one doing it this way until I was dicussing things with SL one day and he shared the same method as one he uses. I will work with on-axis 1 meter measurements as I design a crossover using the tweeter axis as my target axis. I then tweak the crossover listening to music by ear and by using an RTA in my room. I find that the RTA gives me the best representation of the tonal balance that correlates to what I am hearing.

                Most of these adjustments are small, but as you have stated .5 ohms changes on a tweeter's resistor can be clearly heard, and don't show up much different at all in the measurements. These adjustmens are subjective, but with the assistance of something objective as a tool. This is "voicing" a speaker, and I think most people who hear my speakers here at my house really like the way they are voiced, but the biggest compliment I ever received regarding my "voicing" was given to me at a DIY gathering a couple years ago. It especially meant a lot by who said it at the time. So, I think the method works fairly well. By the way, my speakers still measure very well too.

                Jeff B.
                Click here for Jeff Bagby's Loudspeaker Design Software

                Comment


                • #9
                  Re: ZaphMeister article hit a nerve..... *PIC*




                  Thanks for the comments. I wrote that article in February of last year, but it didn't get posted for 6 months because I thought it might make too many people angry.

                  My favorite part of that is "This tweeter sounds dull. Translation: Oops, my kid pulled the treble knob off my preamp, put it back rotated 45 degrees to the right, and then adjusted it so it visually centered."

                  There's a funny true story behind that. (or heart breaking, depending on your view) I had a guy build one of my speakers and make the comment about the dull tweeter. I started the troubleshooting process. (this was back when I accepted emails) After nearly a hundred emails spread out over a month, I pretty much just gave up and said sorry, that's all I've got.

                  A couple weeks later, I get an email something like this: "I hooked my old speakers up and now they sound dull too! I read on the internet about how some speakers can present a dangerous load. I think your speakers wrecked my integrated amp!"

                  At that point I thought to myself "Ok, I'm done dealing with you, moron." and began fiercely ignoring the guy's emails. About another month later, I got the final email from the guy. I'm glad I opened it before deleting it.

                  He had sold the amp (original cost about $800) on ebay with the comment "As is, might need work". The guy who bought it from him ($50) broke the news about the treble knob. So, there it is, all the words apply. Funny, heartbreaking, stupid, mean, thankful. The mean part might come from the buyer happily letting the seller know and of course refusing to give the amp back. The thankful part was me, because even in the midst of the guy's anger, he had the balls to come forward and let me know that it wasn't the speaker.

                  It's a long story, but realize how condensed it is. I just start to quiver a little when I think of all the troubleshooting stuff I went through... and I've got similar stories.


                  (Originally posted by: jkrutke)

                  Comment


                  • #10
                    Re: Some of my thoughts on this.


                    > I read the article you linked and agree with
                    > what was said. Speakers can not be
                    > accurately evaluated subjectively apart from
                    > the system. Within the system subjective
                    > adjustments are what we call
                    > "voicing".

                    > However, it has been my observation that
                    > what we hear and the measurements we take
                    > may not always match up well.

                    > All measurements are taken on some axis.
                    > Listening, on the other hand, may not be on
                    > this same axis, or may be on many different
                    > axes. Also we tend to sit further from our
                    > speakers then when our measurements were
                    > taken. This does two things; changes the
                    > path lengths, and alters the balance of
                    > first arrival and reflected sound. The more
                    > of the power response that falls into this
                    > balance, the less a particular axial
                    > response matters. I'm not saying that it
                    > doesn't matter, only that it's balance
                    > shifts.

                    > As path lengths change so does the phase
                    > relationship between drivers and
                    > consequently, so does their acoustic
                    > summation on that particular axis.
                    > Nit-picking to get perfect phase alignment
                    > on one axis is a bit like straining on a
                    > gnat while swallowing a camel if other axial
                    > responses are not being included in the
                    > model. For example, in a two-way speaker
                    > changing the polarity on the tweeter and
                    > getting a 40 dB null, did not really change
                    > the frequency response of the speaker (at
                    > least it wouldn't if the drivers were not so
                    > directive). It simply changed the axis that
                    > this null laid on. The null was there all
                    > along, just on another axis. Of course, this
                    > example is too simplistic, and other factors
                    > exist that does make the on-axis response
                    > important, but my point is that the power
                    > response remained unchanged by this polarity
                    > flip, and the more of the power response
                    > balance you hear when you listen the less
                    > noticeable this null will be.

                    > Paul, you were talking about baffle step
                    > compensation and so forth, but then posted a
                    > response that showed a 7 dB rise from the
                    > midrange to the lower treble. When you
                    > changed the polarity on your midrange you
                    > were probably compensating for this rise as
                    > you heard it at your listening position.
                    > However, when you did so you threw out all
                    > of that work to get your "perfect"
                    > phase alignment. You also changed the
                    > summation in complex ways because the
                    > midrange in a three-way is summing with the
                    > woofer and the tweeter, while the woofer and
                    > tweeter also sum acoustically with each
                    > other too.

                    > Over the years I developed a method of
                    > measuring the sound of a speaker that seemed
                    > to match up the best to what I was hearing.
                    > I thought I was the only one doing it this
                    > way until I was dicussing things with SL one
                    > day and he shared the same method as one he
                    > uses. I will work with on-axis 1 meter
                    > measurements as I design a crossover using
                    > the tweeter axis as my target axis. I then
                    > tweak the crossover listening to music by
                    > ear and by using an RTA in my room. I find
                    > that the RTA gives me the best
                    > representation of the tonal balance that
                    > correlates to what I am hearing.

                    > Most of these adjustments are small, but as
                    > you have stated .5 ohms changes on a
                    > tweeter's resistor can be clearly heard, and
                    > don't show up much different at all in the
                    > measurements. These adjustmens are
                    > subjective, but with the assistance of
                    > something objective as a tool. This is
                    > "voicing" a speaker, and I think
                    > most people who hear my speakers here at my
                    > house really like the way they are voiced,
                    > but the biggest compliment I ever received
                    > regarding my "voicing" was given
                    > to me at a DIY gathering a couple years ago.
                    > It especially meant a lot by who said it at
                    > the time. So, I think the method works
                    > fairly well. By the way, my speakers still
                    > measure very well too.

                    > Jeff B.

                    Jeff,

                    Very well put. Us noobs can learn a lot from guys like you, John K., Roman, Zaph,etc. I'm reading your "Jeff B's crossover tips" article on AudioDIYcentral. Also a very good read. You are good at wording things so that they are understandable. You should write more, say a monthly or weekly Jeff B. speaker design or crossover design article. ;-);-)

                    Cheers,

                    Dan

                    Dan N.

                    Comment


                    • #11
                      Re: ZaphMeister article hit a nerve.....


                      It's stories like yours that make me glad that I don't try to make a living or even have a side business doing this. All of the fun would soon be gone.

                      dlr
                      WinPCD - Windows .NET Passive Crossover Designer

                      Dave's Speaker Pages

                      Comment


                      • #12

                        Comment


                        • #13
                          That card is classic!!


                          That's pretty good! I enjoyed the comment about the supermodels, pretty crafty.

                          NK
                          I'm just that guy. www.sru.edu Rock Solid.

                          "It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion."

                          L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

                          Comment


                          • #14
                            Still... nothing beats experience with DIY


                            ... for many reasons. One is that inexperienced ears can be fooled very easily. The other is that each driver has to be contoured differently due to many factors that are difficult to measure or model (power response, harmonic distortion, BSC, diffraction, etc.). It is quite a complex process but the combination of measurements and listening is essential and I feel that an optimal crossover requires both to be successful. Knowledge accompanied by experience also helps as well. Knowledge alone is often not enough because there are things with speaker design (as well as my last job as an RF design engineer) that are difficult to interpret numerically (and more importantly subjectively) even if they can be measured. Experience allows you to better convert technical data to what you expect the subjective impression to be. The bottom line is that you'll never stop learning in a field like this (RF design was the same way and they always liked to call it "voodoo magic").
                            RJB Audio Projects
                            http://www.rjbaudio.com

                            Comment


                            • #15
                              Seriously, the seller expected the buyer to return


                              it?1 No way. Uh, I'm selling you a "broken" amp. But if it starts working, you have to return it. Hey, the buyer went through all that time and effort servicing (read, turning the treble up). The punishment for being a moron is occasionally financial loss...

                              So that's why audiophiles don't like treble knobs...

                              Wow, you have a business card...

                              audioheuristics isn't around right now...

                              Comment

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