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Bigger is Better......Or is it? 12" vs 15" vs 18" vs 21" (PA Drivers)

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  • #46
    Originally posted by billfitzmaurice View Post
    For the most part by what it looks like.
    Or by the sound in Guitar Center while battling against an army of crappy guitar players attempting to execute the same metal riff
    Electronics engineer, woofer enthusiast, and musician.
    Wogg Music

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    • #47
      Originally posted by STIchris722 View Post

      I'm trying to figure out how a bassist knows to pick which cabinet configuration without a simple frequency response figure. The only thing mesa provides is power output and the nominal impedance of the cabinets. I haven't heard the new Eden stuff since they sold out to Marshal, but their old stuff I appreciate and they have always provided frequency response. Now granted these responses could be at -10dB for all I know.

      I don't feel as though I have fallen into any "trap." I have played multiple bass cabinets from the same company and they all sound different. We have established why that is now, but that was my original basis for posting this thread was due to this. Different size speakers for bass guitar from the same company sound different. Yes I know now that it's not the size of the speaker that dictates this, but rather the tuning of the cabinet and the specs on the speaker itself.

      Cheers,
      Chris
      Without a graph, and proper measurement parameters the frequency reponse provided by Eden is likely useless as well. I didn't do a full sweep of my Nemesis cabinet, but the all controls flat on the floor RTA measurement I did to compare against my design had some serious variations, such as a 12dB drop at 1kHz, another 12dB variance at around 3k and a bunch of 6dB steps all over the place.
      Electronics engineer, woofer enthusiast, and musician.
      Wogg Music

      Comment


      • #48
        Music Gear is a try before buy scenario, as are many other products ( from Sporting Goods to Speakers etc,etc ).
        A Pickup Band musician ( for a 60s performer ) with diverse gear experience knows gear capability; so despite exaggerated ad copy ( which most products utilize ) Ampeg amps satisfactory met Venue Gear rider contract terms.
        "Not a Speaker Designer - Not even on the Internet"
        “Pride is your greatest enemy, humility is your greatest friend.”
        "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

        Comment


        • #49
          Back to the cab:
          Since the size is set, I'd suggest using the Woofer Selection Guide - Put the list in Vented Volume Order and note the differing drivers that fit the desired size (4.271cu ft?).
          It shows how a variety of options and driver/tuning relationships.
          As the maxim "No Free Lunch" applies it reflects the compromises in design; Modeling and simulation shows it explicitly.
          "Not a Speaker Designer - Not even on the Internet"
          “Pride is your greatest enemy, humility is your greatest friend.”
          "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

          Comment


          • #50
            Originally posted by Sydney View Post
            Back to the cab:
            Since the size is set, I'd suggest using the Woofer Selection Guide - Put the list in Vented Volume Order and note the differing drivers that fit the desired size (4.271cu ft?).
            It shows how a variety of options and driver/tuning relationships.
            As the maxim "No Free Lunch" applies it reflects the compromises in design; Modeling and simulation shows it explicitly.
            Sydney -- I changed the height of the box to give me some more volume, but I'm still only around 6 something. The curve does look much better though. What are your thoughts? Again this would be for bass guitar. I like how the Fb and F3 are the same now.

            Cheers,
            Chris
            "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

            Comment


            • #51
              Originally posted by STIchris722 View Post
              ...The curve does look much better though. What are your thoughts? Again this would be for bass guitar. I like how the Fb and F3 are the same now....
              Does look better.
              I noticed that 2 of my favorite ( world famous ) Bass players use a 4x10 augmented ( when necessary ) with either a 15 ( like a Hartke HyDrive 115 ) or an 18" ( SWR Big Ben 1x18 ).
              A bass player once told me that NO one messes with his Tone, so I don't .

              "Not a Speaker Designer - Not even on the Internet"
              “Pride is your greatest enemy, humility is your greatest friend.”
              "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

              Comment


              • #52
                Originally posted by Sydney View Post
                Does look better.
                I noticed that 2 of my favorite ( world famous ) Bass players use a 4x10 augmented ( when necessary ) with either a 15 ( like a Hartke HyDrive 115 ) or an 18" ( SWR Big Ben 1x18 ).
                A bass player once told me that NO one messes with his Tone, so I don't .
                Sydney -- Amen to that. I helped my brother (the touring musician) install EMG pickups in his guitar tonight so he could get the "tone" he was looking for!
                "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

                Comment


                • #53
                  Originally posted by Sydney View Post
                  Back to the cab:
                  Since the size is set, I'd suggest using the Woofer Selection Guide - Put the list in Vented Volume Order and note the differing drivers that fit the desired size (4.271cu ft?).
                  It shows how a variety of options and driver/tuning relationships.
                  As the maxim "No Free Lunch" applies it reflects the compromises in design; Modeling and simulation shows it explicitly.
                  Sydney -- What do you think of this? I made it 8 cubes and got a pretty nice flat response. The box doesn't look crazy big either.
                  "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

                  Comment


                  • #54
                    I see ( the slight bump ) it reflects the onset of ripple. Personally I don't see any reason for going that large with Vb greatly exceeding Vas ( or beyond 7 cu ft ).
                    My guess is that transient performance would begin degrading.
                    B&C published: Cabinet Size - 7.0 cu. ft. / 200 Liters Tuning - 32Hz for -3dB - 32.2Hz (EBS Tuning)

                    Certainly you know what you are willing/able to tote; One suggestion I endorse is to slap together a cardboard box of final size.
                    I know once I saw how big the box would be, it was helpful; Granted I'm in Geezerhood and guys my age don't/can't lift big heavy stuff so...

                    EDIT: This is a Voice Coil Review by Vance Dickason on that driver
                    This included two vented alignments:
                    A 4.05 ft3 Chebychev/Butterworth type box with 15% fiberglass fill material tuned to 42 Hz, and the factory recommended 7.06 ft3 vented alignment enclosure with 15% fiberglass fill material tuned to 32 Hz. This is was actually an extended bass shelf (EBS) type of alignment.
                    "Not a Speaker Designer - Not even on the Internet"
                    “Pride is your greatest enemy, humility is your greatest friend.”
                    "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                    Comment


                    • #55
                      Originally posted by Sydney View Post
                      I see ( the slight bump ) it reflects the onset of ripple. Personally I don't see any reason for going that large with Vb greatly exceeding Vas ( or beyond 7 cu ft ).
                      My guess is that transient performance would begin degrading.
                      B&C published: Cabinet Size - 7.0 cu. ft. / 200 Liters Tuning - 32Hz for -3dB - 32.2Hz (EBS Tuning)

                      Certainly you know what you are willing/able to tote; One suggestion I endorse is to slap together a cardboard box of final size.
                      I know once I saw how big the box would be, it was helpful; Granted I'm in Geezerhood and guys my age don't/can't lift big heavy stuff so...

                      EDIT: This is a Voice Coil Review by Vance Dickason on that driver
                      This included two vented alignments:
                      A 4.05 ft3 Chebychev/Butterworth type box with 15% fiberglass fill material tuned to 42 Hz, and the factory recommended 7.06 ft3 vented alignment enclosure with 15% fiberglass fill material tuned to 32 Hz. This is was actually an extended bass shelf (EBS) type of alignment.
                      Sydney -- It's strange.....It must have been something with taking the screenshot because that bump isn't there on my screen in the software. Never the less, I understand what you are saying about not needing additional volume once you have exceeded the Vas. You may have already answered this, but in the communication regarding using this speaker in a bass guitar bottom, what is the negative of using too small of a cabinet? I can see on the frequency response curve what it will due, but is there anything else?

                      On another note, I feel like I have finally found someone on here I can talk to without feeling like there is a condescending tone coming from their comments. I write this post as I drink some coffee and listen to some Joe Bonamassa. mmmm.

                      Cheers,
                      Chris
                      "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

                      Comment


                      • #56
                        Originally posted by STIchris722 View Post
                        On another note, I feel like I have finally found someone on here I can talk to without feeling like there is a condescending tone coming from their comments. I write this post as I drink some coffee and listen to some Joe Bonamassa. mmmm.

                        Cheers,
                        Chris
                        It happens everywhere, especially online. Every group/forum will have extremely talented, bright, intelligent people who have seen a lot before those that come after them. I got a lot of flak on my post a while back simply because I wasn't a "regular" who already had some kind of proven design from ages ago, and thus wasn't part of "the crew" here. Automatically assumed this was the very first speaker I planned on building, thought I knew nothing, was actually given instructions to not buy any speakers with my money until I received approval from the grand jury here! The works. Ha-F'ing-Ha. I learned long ago to grow thick skin. Just flip 'em the bird and learn as you go, but do keep moving. :D

                        Comment


                        • #57
                          Originally posted by STIchris722 View Post
                          ..., what is the negative of using too small of a cabinet? I can see on the frequency response curve what it will due, but is there anything else?

                          On another note, I feel like I have finally found someone on here I can talk to without feeling like there is a condescending tone coming from their comments. I write this post as I drink some coffee and listen to some Joe Bonamassa. mmmm.

                          Cheers,
                          Chris
                          Chris - That VC article by Vance Dickason does show ( in other graphs ) other performance aspects that differ from the 2 tunings provided.
                          ( PM sent with material to drink coffee to. )

                          Questions:
                          How familiar are you with the Concepts behind T/S parameters? I was going to include an embedded link in this forum's Speaker Building Bible - but alas it's dead .
                          How are you going to drive this sub?
                          Split feed into a separate amp?
                          Last edited by Sydney; 02-18-2018, 11:50 AM.
                          "Not a Speaker Designer - Not even on the Internet"
                          “Pride is your greatest enemy, humility is your greatest friend.”
                          "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                          Comment


                          • #58
                            Originally posted by STIchris722 View Post
                            what is the negative of using too small of a cabinet? I can see on the frequency response curve what it will due, but is there anything else?
                            The negatives are subjective. For example, just as you mentioned the frequency response changes (in essence, the sensitivity capability on the low-corner is reduced as you reduce cabinet volume). For bass-reflex alignments, it may change the porting requirements from a physical standpoint (sometimes harder to fit the port if it is too long). Smaller than optimum cabinets produce more stress on the cones because they must be able to resist deformation, but that also depends on just how hard you're going to drive the speaker. The port contribution to the low-corner end is narrower on the frequency scale, and thus the woofer has to work just a bit more just before you descend to the tuning frequency.

                            But on the positive side, smaller cabinets with relatively flat alignments tend to have lower group delay within the useable passband. Basically the less "deep bass" you require from a cabinet from an alignment standpoint, the better (lower) the group delay will be. Also, the cone excursion minimum dip centered at the system tuning frequency is widened compared to a larger cabinet. This means the port contributes a greater percentage to the output at the [relatively] deeper end and the woofer cone excursion ends up being damped more.

                            WinISD Pro is great for visualizing this because you can use your mouse cursor to change either or both cabinet volume and/or system tuning frequency and see in real-time the changes to the graph you are currently viewing.

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