Harmony Central Forums
Announcement Announcement Module
Collapse
No announcement yet.

Speaker magnet size

Page Title Module
Move Remove Collapse









X
Conversation Detail Module
Collapse
  • Time
  • Show
Clear All
new posts

  • Speaker magnet size

    reading the 'describe your 1st PA' thread, I was recalling the speakers we used back then. In my case, EV SRO 12s in my Sunn Solaris guitar amp and SRO15's in the PA and bass cabs. Both had huge, heavy magnet structures, 15 lbs and 18 lbs respectively if memory serves. My bandmates guitar amp had a JBL 15 with a similarly large magnet. Seems like just about any upgrade speaker back then had much larger magnets than the stock speakers (Jensens in my case).

    Today's speakers don't seem to have anywhere near as large/heavy magnets. I'm curious as to the difference in engineering of today's speakers vs. those from that time period.
    http://www.soundclick.com/bands/page...?bandID=742896
    http://www.volunteersband.com

  • #2
    The neodynium magnets used today in higher end speakers provide the same magnetic field strength with a lot less mass (weight). It's different material with different properties.
    Hamer SB4 Bass Guitar
    Ampeg B100R Bass Amp

    Comment


    • #3
      Older alnico magnets were smaller compared to ceramic and now neo dwarfs them all in size/weight. But if the magnetic flux density were all the same, the speakers would all be the same, save maybe some minor differences caused by heat wicking.
      Don Boomer

      Comment


      • #4
        The other difference is that pole and gap geometry has improved to allow better utilization of the magnetic field so even with ceramic a smaller magnet will result it the same flux density where it counts.
        -------------------------------------------------------------------------------------------------------------------------------------------------------------------
        Former product development engineer: Genz Benz, a KMC Music/Fender Musical Instruments Company, continuing factory level product support and service for Genz Benz

        Currently product development engineer: Mesa Boogie

        Comment


        • #5
          reading the 'describe your 1st PA' thread, I was recalling the speakers we used back then. In my case, EV SRO 12s in my Sunn Solaris guitar amp and SRO15's in the PA and bass cabs. Both had huge, heavy magnet structures, 15 lbs and 18 lbs respectively if memory serves. My bandmates guitar amp had a JBL 15 with a similarly large magnet. Seems like just about any upgrade speaker back then had much larger magnets than the stock speakers (Jensens in my case).

          Today's speakers don't seem to have anywhere near as large/heavy magnets. I'm curious as to the difference in engineering of today's speakers vs. those from that time period.
          Pretty sure Standard EV have about the same size mags today as they had 30 years ago. Same with most of the similar models. There's still a huge difference between a stamped frame guitar speaker and a high-end cast frame model.
          tlbonehead@yahoo.com
          www.myspace.com/tbone_tommy
          -For Sale:
          -set of GFS Dream 90s- gold and black pearl- $40 shipped in the cont. US
          -(2) Celestion G12M-70 16 ohm guitar speakers in good condition $40 ea. + shipping.
          - Vox VT15 Valvetronix very clean - $85 + shipping
          - Hughes Kettner Edition Tube 20 (the early Voxy sounding one) Sounds & looks good. $250 + shipping. SOLD
          - Crate Palomino V8 - 10" Celestion - Very clean - on Ebay (sold)

          Comment


          • #6
            How important is the magnet size? how does it affect the sound quality?

            Comment


            • #7
              How important is the magnet size? how does it affect the sound quality?


              Magnet size means nothing.

              Magnet strength and how the magnetic field is focused into the gap is what matters. High magnetic field strength and number of turns of wire in the gap defines the available force and is one parameter that is used to develop a speaker's properties. Means different things dependingon the speaker's bandwidth.
              -------------------------------------------------------------------------------------------------------------------------------------------------------------------
              Former product development engineer: Genz Benz, a KMC Music/Fender Musical Instruments Company, continuing factory level product support and service for Genz Benz

              Currently product development engineer: Mesa Boogie

              Comment


              • #8
                agedhorse...how then does a magnet 'strength' affect the speaker's frequency response? The stronger the magnet 'force'...the more 'pwoerful' it is? Sorry for the silly question.

                Comment


                • #9
                  agedhorse...how then does a magnet 'strength' affect the speaker's frequency response? The stronger the magnet 'force'...the more 'pwoerful' it is? Sorry for the silly question.


                  and maybe a followup question; what parameters determine a speakers 'efficiency'? Going back to my original post, the difference in sound output from the stock Jensens in my Sunn Solaris vs. the EV SRO12s was substantial. Being young and uninformed at the time (now I'm older and still uninformed), I assumed the magnet size was involved, and maybe the 'edge wound voicecoil' advertised with the SRO's. I'm sure it's not that simple.
                  http://www.soundclick.com/bands/page...?bandID=742896
                  http://www.volunteersband.com

                  Comment


                  • #10
                    This is a much more complicated question than I think you realize.

                    Magnet strength is one parameter that geverns the available force to move the cone. There are other parameters (such as weight, wire turns in the gap, spring constants, piston area, damping, winding height and inductance that affect the frequency response and efficiency/sensitivity. All of these tradeoffs interact with each other.
                    -------------------------------------------------------------------------------------------------------------------------------------------------------------------
                    Former product development engineer: Genz Benz, a KMC Music/Fender Musical Instruments Company, continuing factory level product support and service for Genz Benz

                    Currently product development engineer: Mesa Boogie

                    Comment


                    • #11
                      agedhorse...how then does a magnet 'strength' affect the speaker's frequency response? The stronger the magnet 'force'...the more 'pwoerful' it is? Sorry for the silly question.


                      Generally the magnet strength itself bears little to frequency response. There are mechanical issues, suspension, cone weight and material that greatly affect things.

                      So here's one you wouldn't think of ... too strong a magnet will limit low frequency response ( at least with current technologies). More than about 14k gauss.
                      Don Boomer

                      Comment


                      • #12
                        This is a much more complicated question than I think you realize.



                        You're right, and that's why I appreciate having engineers and other experts on this forum to help me understand. Greatly appreciate the responses.
                        http://www.soundclick.com/bands/page...?bandID=742896
                        http://www.volunteersband.com

                        Comment


                        • #13
                          this is not as easy to grasp as I thought...but I appreciate the effort you gusy took to reply.

                          Comment


                          • #14
                            this is not as easy to grasp as I thought...but I appreciate the effort you gusy took to reply.


                            Rarely can quality or performance be judged by just one parameter... otherwise, if bigger magnets = better, choices would be simple.

                            FWIW: The tomatoes from my garden were red when they were ripe, but not nearly as strikingly red as the tomatoes in the grocery store... but the tomatoes from my garden generally tasted considerably better.

                            There was a great quote in the movie Jerrasic Park, when the kid was playing with the binoculars. An adult (possibly Dad) said: "Quit playing with those." The kid said: "Why?" Dad said: "Cause they're expensive" Kid said: "How do you know?" Dad said: "Are they heavy?" Kid said: "Yea!" Dad said: "Then they're expensive.".

                            Comment


                            • #15
                              There was a great quote in the movie Jerrasic Park, when the kid was playing with the binoculars. An adult (possibly Dad) said: "Quit playing with those." The kid said: "Why?" Dad said: "Cause they're expensive" Kid said: "How do you know?" Dad said: "Are they heavy?" Kid said: "Yea!" Dad said: "Then they're expensive.".


                              Not that it really matter, but I'm pretty sure that it was actually a lawyer who said that in the movie. In some ways, I think that makes the analogy even better.
                              "A performer without techs is standing naked, on a dark stage, and no one can hear them. A tech without a performer... has marketable skills."

                              Comment



                              Working...
                              X