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

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  • #31
    Originally posted by STIchris722 View Post
    ...Oh okay. so VAS and Qts give the builder an idea of what size enclosure they should be building? This is the reason the builder can't just throw a driver in any size box? I guess in my ignorance I was just trying to model both in the same foot print of cabinet so they would fit the rest of the bass cabinets I have designed. So what are your recommendations for the 18?
    Any 18 I'm aware of performs better in a cab larger 4.27 cu ft. or you get a similar shaped response ( w 35hz being well down ).
    example - A Claire 18.00SW will get a freq @ -3db of 28.41Hz but requires a 7.55 cu ft cab ( almost twice the size ).
    So there is the compromise.
    Eminence as a service often publishes several options for their woofers with options of cab size. In these the differences in response curves are very apparent between cab sizes.
    In all likelihood, for a cab 4.27cu ft - a 15" woofer would provide a flatter response.
    As the Eden has a much higher sensitivity - the sub will have to be pushed harder to integrate better.
    "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."

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    • #32
      Originally posted by STIchris722 View Post

      So what happens at the resonant frequency of the driver if it is placed in a box that is tuned below it? I guess my understanding was that at the Fs, the driver freely resonated causing a mess. Does that change once it is placed into a box with a different tuning frequency? If so what happens as it approaches the Fs?

      Again for arguments sake, let's assume we are talking about the B&C 18TBW100 as this is one that I have modeled several different ways.

      It's not that Fs changes, the whole system fundamentally changes when you compare it to a sealed enclosure. A free-air driver as such from this discussion is fundamentally a damped harmonic oscillator. Aka: Mass suspended on a spring, with damping. Put it in a sealed enclosure, the spring and damping change (for the most part). But, put the driver in a bass-reflex enclosure and now you have a Helmholtz resonator that is fundamentally a double-mass-spring damped harmonic oscillator. The whole meaning of "Fs", meaning the "individual" resonance of the "larger" mass-spring-damper system, disappears because [within the frequency range of interest] you cannot drive one portion of the double-mass-spring damped harmonic oscillator while completely ignoring the effects of the smaller attached mass-spring-damper system (the enclosure tuning). The system fundamentally changes. This may not be of much significance with regards to the initial query, but perhaps you can better understand the different things going on (or at least the fact that things are different) in bass reflex enclosures (with perhaps some more additional reading on your part).

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      • #33
        Originally posted by billfitzmaurice View Post
        You get different tones because the drivers and cabs are different, but it's not the driver size that makes them different. In blind testing you can't tell what size driver is being used. For that matter you could load a dozen different drivers of the same size into the same cabinet and they'd all sound different. A typical statement is that fifteens are better in the lows, and tens are better in the highs. That certainly doesn't apply when comparing the response of cabs loaded with an EVM-15L versus an Eminence BP-102, and that's by no means an isolated case.
        Bill -- Okay now we are on the same page. I think what you were trying to convey earlier and how I was interpreting it weren't meshing well. For arguments sake, if a company was to build proportionally identical drivers in 10", 12", 15", 18", etc, and you were to put them in proportionally identical enclosures to the same tuning frequency, they would all sound the same (let's ignore bass extension for this example). I totally agree with your comment about the 10s and the 15; this has always been a bogus statement by bass players. now with that said, if I take an Eminence CA1059 2x10 combo cabinet and compare it to a Eminence Kappalite 3015 cabinet with a different tuning frequency, are they not going to have a different "tone" in how they reproduce the sound of my bass? I would say yes, but I want to make sure we are on the same wavelength here.

        Where I was getting confused earlier is that from brand to brand in the same size speaker I have heard differences in tone and from what I gathered from you, you were saying that wasn't possible. I have built many guitar cabs to know that speakers play a big role in how the cabinet sounds, regardless of distortion. I mean the material of the cone, the magnet material (so they say), the angle of the cone, the dust cover size and material, can all play a role in how a speaker sound (for guitar that is). Not to change the subject but the EM12 by Eminence is still one of my favorite sounding guitar speakers. 1st place would go to the 12" screaming eagles by Eminence, but they don't make them anymore.....shame

        The picture below was an experimental project of mine and one of my earlier projects. This project illustrated perfectly the "beaming" effect you were referring to earlier. I didn't notice is so much at low volumes, but when the gain was cranked up, the 12" sang beautifully in the mids while the 15" had something strange going on. Both were crossed at 1.5KHz to the same compression drivers and wave guides. This is when I realized that 1.5KHz is way too high for a 15" speaker to play successfully without the beaming effect. That and I don't know if the Eminence 3012HO is voiced that much differently than the Kappalite 3015, but it sure sounds better, especially in the vocals and overall clarity. Interesting sounding cabs with the wave guides I selected. Fun, but expensive build!

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

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        • #34
          Originally posted by STIchris722 View Post
          I think what you were trying to convey earlier and how I was interpreting it weren't meshing well. For arguments sake, if a company was to build proportionally identical drivers in 10", 12", 15", 18", etc, and you were to put them in proportionally identical enclosures to the same tuning frequency, they would all sound the same
          They would on-axis if they all had identical specs and identical response, which is rare, but possible. They would not have identical polar response, because that is the one and only factor which is affected by the size of the cone.

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

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          • #35
            Originally posted by Chris Roemer View Post
            My understanding (although I'm NOT a musician, . . . the only thing I play is the stereo) is that there are so many cabs/cab styles (for guitar & bass) because they each have a different sound - mostly attributed to distortion characteristics of the drivers/amps (esp. tube amps?). Guitar combos aren't meant to be low distortion, it's the distortion that makes them sound cool and unique ! (Heck, how many different flavors of just 10" (or 12") drivers does Celestion make (or Eminence) ? )
            Most electrics guitar "effects" ARE distortion, aren't they?
            I had a major "aha!" moment when a musician explained it to me something like this: "You play the guitar, the amp, and the pedals or whatever as a single instrument. That's why you often see a smaller amp on the stage with a microphone in front of it. Essentially, everything behind that microphone is the instrument."

            More recently, I heard John Fogerty explaining how he got one of his signature sounds by playing a certain guitar while standing between two huge speaker stacks. He was kind of surfing the feedback, as I understand it. Whatever the physics, the sound is cool as hell.


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            • #36
              As one who has taken lessons on numerous musical instruments ( w/o becoming a "Musician" ); I resigned to serve in the shadows as a board monkey for decades:
              The common sentiment I've encountered is - it's about Tone.
              Distortion is just a part of the Tone Palette.
              This vid demonstrates that:
              https://www.youtube.com/watch?v=WNNkbE6EU3w
              "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


              • #37
                So I feel like we have gone full circle here. Do different size speakers have different tone? The reason I'm asking is because I have Eden bass cabinets with nearly identical tunings, but with different size speakers and they definitely sound different. I don't know if tone is the right word though.

                Guitar speakers thought....I'll take to the grave that every brand and model sounds different and the size does play a role. Maybe the cabinet has something to do with it, but the best cabinet I ever built had a 12" speaker in it for my brother who is a professional touring musician. I don't know; I'm not trying to argue, but I guess I am confused about this subject still. More so with the bass cabinets.

                Then you have companies like Mesa who don't provide any specs on their bass cabinets. I have a hilarious email thread with them about it that I should share.

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

                Comment


                • #38
                  Originally posted by STIchris722 View Post
                  So I feel like we have gone full circle here. Do different size speakers have different tone? The reason I'm asking is because I have Eden bass cabinets with nearly identical tunings, but with different size speakers and they definitely sound different.
                  The tuning of the cab only affects the low frequency response. At least 90% of what we call 'tone' comes from the midrange and high frequencies, which are unaffected by the cab tuning or cone area. I don't know why you keep going round and round with this, if size mattered all tens would sound the same, all twelves would sound the same, all fifteens would sound the same, and so forth.

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

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                  • #39
                    It's not the size that matters, but the response and distortion profiles that will create the tone of the speaker. But the amp and its distortion settings will dwarf what the driver contributes.
                    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
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                    • #40
                      Originally posted by billfitzmaurice View Post
                      I don't know why you keep going round and round with this, if size mattered all tens would sound the same, all twelves would sound the same, all fifteens would sound the same, and so forth.
                      Bill -- I am sorry, but i wouldn't post a question if I didn't have some uncertainty or something wasn't clear to me. Clarity is also left to perception. My perception was that we were on the same page and then you said something which left be with some lack of clarity which in turn felt like a full circle conversation. My apologies, but I hope I am not receiving criticism over this. As I state in every comment, I am not an expert. I ask questions because I don't know the answer to something and I look to people like you for the answer.

                      I'm still not clear on all of this, but feel as though I have struck a nerve of annoyance within the community.

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

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                      • #41
                        Originally posted by STIchris722 View Post
                        Bill -- I am sorry, but i wouldn't post a question if I didn't have some uncertainty or something wasn't clear to me. Clarity is also left to perception. My perception was that we were on the same page and then you said something which left be with some lack of clarity which in turn felt like a full circle conversation. My apologies, but I hope I am not receiving criticism over this. As I state in every comment, I am not an expert. I ask questions because I don't know the answer to something and I look to people like you for the answer.
                        I'm still not clear on all of this, but feel as though I have struck a nerve of annoyance within the community.
                        Chris
                        I see part of this as the weakness of text communication.
                        Guitar speakers thought.......Then you have companies like Mesa who don't provide any specs on their bass cabinets....
                        Speakers for such use (Music production) are considered different that those for Music Re-Production.
                        Guitar/Bass speakers are not sold by T/S specs., but often in comparison to established commercial products (British Sound/Texas/Jazz etc,etc.).
                        Musicians have a Tonal language, with words that describe Tonal aspects of produced sound.
                        Coned EM speakers have been around since about 1927, so basic characteristics of the physics of their operations is well studied.
                        The most recent (from Klippel) shows the performance regions of drivers ( such as resonance and breakup, etc ).
                        Designs for Guitars drivers take aspects such as Breakup and Magnet Saturation to be part of the goal to produce desired Tone.
                        Click image for larger version

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                        I don't know if this FR is representative of your Eden cab ( from what I've heard of such cabs - it would seem fairly typical )
                        Heck of a drop from 110Hz down - 50hz is -10db )

                        These cabs have horns tweeters - as an experiment : If these were blocked ( or disconnected ) how would the Tone be affected
                        "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


                        • #42
                          What's annoying is when people make subjective pronouncements with no data to back them up, for instance 'tens sound different than fifteens'. When asked to provide objective data to prove it none is presented, because none exists. It's not your fault that you've fallen into that trap, because electric bass speaker manufacturers have been saying it for 70 years. What's a bass player to think when they read this in one ad: The combined air-moving capability of eight 10″ speakers reacts faster to transients than fifteens or eighteens and this in another: when both statements are from the same manufacturer (Ampeg) and neither is true?

                          I expect your conversation with Mesa was very much along those lines, you asking for objective data, and they giving you one excuse after another why objective data doesn't matter. There are two possible reasons why Mesa won't give you an SPL chart. The first is that they don't want you to see it, as it will show their sensitivity and frequency response claims are false. The second is that they don't have one. That's not as far fetched as it might seem. I've designed quite a few commercial electric bass cabs, always offering to the manufacturer a full set of measurements, not only axial SPL, but full polar and waterfall plots as well. None have ever had any interest in them. The reason? They all say 'our customers don't care about that'.

                          This is a measured response chart of the Eden 410XLT. Nothing about it indicates what size the woofers are. You can find many cabs loaded with fifteens that don't go as low, or eighteens that go higher.
                          www.billfitzmaurice.com
                          www.billfitzmaurice.info/forum

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                          • #43
                            They're right, the typical musician doesn't care about that. However, if you're a musician on this forum you likely do care about that but should consider yourself a small minority. I'm a bassist as well, and have been using my own bass cabinets for decades.

                            For a long time my main rig was my stack with an Eminence 15" in a large bass reflex cab crossed at 200Hz to a 4x6.5" MCM aluminum cone cabinet + a bullet tweeter. At the time, I didn't have the tools to properly cross that tweeter, so there is no low pass on the 6.5" drivers and a 3rd order textbook filter on the tweeter somewhere around 5k. I put a ton of miles on that setup. I've also had an Eden Nemesis 2x10" combo amp that I bought specifically because it's much much smaller and pretty lightweight for it's power. Totally different tone between them, and if you try to play music through either of them it's immediately apperent that they are not anywhere near what we would call accurate or flat.

                            Last year I re-did a very small practice amp with a single 8" and a horn loaded dome tweeter using proper crossover modeling and design. This is the first amp I've used with a proper frequency response, it measures +-3dB from about 2k up to 15k, and about +-5dB if you go down to 50Hz. Playing music through that thing is actually pleasureable, and loud. It's also the best sounding bass amp I've ever used, and it makes me want to re-design my 4x6.5" cab for a proper frequency response. I gig with that little sucker now, using my Eden Nemesis as the low end with a 200Hz crossover to the little guy.
                            Electronics engineer, woofer enthusiast, and musician.
                            Wogg Music

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                            • #44
                              Originally posted by wogg View Post
                              They're right, the typical musician doesn't care about that. However, if you're a musician on this forum you likely do care about that but should consider yourself a small minority. I'm a bassist as well, and have been using my own bass cabinets for decades.
                              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
                              "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

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                              • #45
                                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.
                                For the most part by what it looks like.

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

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