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  • Question about my speakers and midrange resolution or lack of it.

    Hi everyone, I'm trying to figure out if I can squeeze more out of this setup with regards to midrange clarity or resolution I guess.

    I have a pair of large two ways made up of old 8" Camber driver and a 1" Vifa D27GT45 and while the speakers sound very pleasing to me and response is smooth... I find that in some situations, it has a lack of resolution in the midrange when compared to my little usher S520 bookshelf speakers (5" and 1" dome). The driver probably is a 9" but I call it an 8" because the piston area is more similar to 8" drivers. Just has a big frame. Its this kind of driver.

    http://www.ebay.com/itm/single-vinta...-/220960131547

    For easy and laid back music, its always great but when there are a lot of sounds at different volume levels in the midrange all happening around the same time, the quiet sounds tend to get lost where I can hear them in the S520 bookshelf speakers. One song I was listening to (cant remember exactly what it was) where I could just barely tell that there were two male voices singing at the same time with one being quieter than the other and sometimes being just a tad leading or trailing the main singer. Thats how I heard it on the small speakers. On my big two ways, I can only only really hear the main singer. Only a couple times I can make out the other singer and thats only because I'm trying real hard to hear it. If I find the song again, I'll update so you guys cna listen to the same track.

    Is this just the nature of it being a larger driver or the quality of the driver or can crossover contribute to this as well? Right now I've got the 8 and tweeter crossed over at approx 2.3Khz 2nd order. The driver actually rolls off around that point very gently without much drama or big spikes or breakup (at least nothing I see on an RTA). I've got just a coil on the driver right around where it rolls off to try and create a 12db accoustic roll off. The tweeter is second order. Cap, coil and an lpad. The coils are Solen 18 guage air coils and cap is a solen poly cap. Resistors are those big white ceramic ones 10w rating. Most of what I feel is lost dont seem like they are high in frequency (somewhere between 500Hz and 1Khz) so i'm blaming the woofer but maybe there is more going on?

    This was really my first attempt for a build and I've fiddled with the crossover quite a bit so far this is the best I've gotten it. I like it more than my Usher S520 but I just want that last bit of detail in the mid which I cant get and maybe it is what it is and I will never get it with this setup. Sigh.

    Any insight is welcome but I'm guessing I just need better drivers and possibly smaller ones but I figured I'd ask for help first

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  • #2
    Re: Question about my speakers and midrange resolution or lack of it.

    If I had to venture a guess, I would say the biggest issue is the CTC spacing. Looks like your CTC is about 6.5-7 inches. At 23ooHz crossover, I believe the minimum, ideal would be around 3 inches CTC. You are probably getting a lot of lobing with that setup which is hurting the mid range clarity. I'm not an expert, but this would be my first guess as to the problem...
    HAGD,
    Marc

    Even though I try to tell everyone upfront, understand that I am still a Newb. I wish the status of Seasoned Veteran/Senior Member, etc. was earned with time not posts...

    TMWW thread

    Maurbacs DCR Tower

    Comment


    • #3
      Re: Question about my speakers and midrange resolution or lack of it.

      Originally posted by contoursvt View Post
      Hi everyone, I'm trying to figure out if I can squeeze more out of this setup with regards to midrange clarity or resolution I guess.

      I have a pair of large two ways made up of old 8" Camber driver and a 1" Vifa D27GT45 and while the speakers sound very pleasing to me and response is smooth... I find that in some situations, it has a lack of resolution in the midrange when compared to my little usher S520 bookshelf speakers (5" and 1" dome). The driver probably is a 9" but I call it an 8" because the piston area is more similar to 8" drivers. Just has a big frame. Its this kind of driver.

      http://www.ebay.com/itm/single-vinta...-/220960131547

      For easy and laid back music, its always great but when there are a lot of sounds at different volume levels in the midrange all happening around the same time, the quiet sounds tend to get lost where I can hear them in the S520 bookshelf speakers. One song I was listening to (cant remember exactly what it was) where I could just barely tell that there were two male voices singing at the same time with one being quieter than the other and sometimes being just a tad leading or trailing the main singer. Thats how I heard it on the small speakers. On my big two ways, I can only only really hear the main singer. Only a couple times I can make out the other singer and thats only because I'm trying real hard to hear it. If I find the song again, I'll update so you guys cna listen to the same track.

      Is this just the nature of it being a larger driver or the quality of the driver or can crossover contribute to this as well? Right now I've got the 8 and tweeter crossed over at approx 2.3Khz 2nd order. The driver actually rolls off around that point very gently without much drama or big spikes or breakup (at least nothing I see on an RTA). I've got just a coil on the driver right around where it rolls off to try and create a 12db accoustic roll off. The tweeter is second order. Cap, coil and an lpad. The coils are Solen 18 guage air coils and cap is a solen poly cap. Resistors are those big white ceramic ones 10w rating. Most of what I feel is lost dont seem like they are high in frequency (somewhere between 500Hz and 1Khz) so i'm blaming the woofer but maybe there is more going on?

      This was really my first attempt for a build and I've fiddled with the crossover quite a bit so far this is the best I've gotten it. I like it more than my Usher S520 but I just want that last bit of detail in the mid which I cant get and maybe it is what it is and I will never get it with this setup. Sigh.

      Any insight is welcome but I'm guessing I just need better drivers and possibly smaller ones but I figured I'd ask for help first

      [ATTACH=CONFIG]31816[/ATTACH]
      How well braced is the box? Did you use any stick on type damping material inside? Are there any partitions inside to break up standing waves? What did you use for filler material? My prefered material is rigid fiberglass, and lots of it. I use ceiling tiles that are about 1" thick fiberglass with a material stuck to one side. The material peels off easily.

      Comment


      • #4
        Re: Question about my speakers and midrange resolution or lack of it.

        Here's an easy one: Swap them left and right, so the tweeters are offset to the middle. It *might* let you hear more in the midrange, and I think it would probably improve the imaging, as well. Worth a try, and no disassembly required.

        Mark
        You go your way, I'll go mine. I don't care if we get there on time.

        ~Pink Floyd

        Comment


        • #5
          Re: Question about my speakers and midrange resolution or lack of it.

          You sure about that calc? Looks to me like the "rule of fumb" would be a CTC of ~5.75 - 5.85" @ 2300Hz. Speed of sound / CTC = XO freq or SOS / XO = CTC.


          Originally posted by WernerM View Post
          If I had to venture a guess, I would say the biggest issue is the CTC spacing. Looks like your CTC is about 6.5-7 inches. At 23ooHz crossover, I believe the minimum, ideal would be around 3 inches CTC. You are probably getting a lot of lobing with that setup which is hurting the mid range clarity. I'm not an expert, but this would be my first guess as to the problem...
          I was so much older then, I'm younger than that now.
          OS MTMs http://techtalk.parts-express.com/sh...d.php?t=220388
          Swope TM http://techtalk.parts-express.com/sh...d.php?t=221818
          Econowave and Audio Nirvana AN10 fullrange http://techtalk.parts-express.com/sh...d.php?t=216841
          Imperial Russian Stouts http://techtalk.parts-express.com/sh...=1#post1840444
          LECBOS. http://techtalk.parts-express.com/sh...ghlight=lecbos

          Comment


          • #6
            Re: Question about my speakers and midrange resolution or lack of it.

            Originally posted by contoursvt View Post
            Right now I've got the 8 and tweeter crossed over at approx 2.3Khz 2nd order. The driver actually rolls off around that point very gently without much drama or big spikes or breakup (at least nothing I see on an RTA).
            If there is a problem it should show up on the RTA. If you can hear it, you can measure it.
            www.billfitzmaurice.com
            www.billfitzmaurice.info/forum

            Comment


            • #7
              Re: Question about my speakers and midrange resolution or lack of it.

              For bracing I evenly spaced (as much as possible) two dividers with two rectangles cut out of it to sort of create an H shape, I also put a dowel right in between the little bit of wood between the cutouts of the tweeter and woofer going to the back wall because teh wood was thin. The front baffle is 1" thick, the rest is 3/4" and I opened up the back side of the woofer cutout a bit with a router.

              I didnt use any stick on sound dampening but I did use 1 1/2" thick of rockwool to line about 3/4 of the way down either side and about half way on the front and back walls. The bottom 1/4 of the cabinet doesnt really have any dampening though.


              Originally posted by rpb View Post
              How well braced is the box? Did you use any stick on type damping material inside? Are there any partitions inside to break up standing waves? What did you use for filler material? My prefered material is rigid fiberglass, and lots of it. I use ceiling tiles that are about 1" thick fiberglass with a material stuck to one side. The material peels off easily.

              Comment


              • #8
                Re: Question about my speakers and midrange resolution or lack of it.

                Hmm ok I will give it a try. Not sure why I have not yet

                Originally posted by Mark65 View Post
                Here's an easy one: Swap them left and right, so the tweeters are offset to the middle. It *might* let you hear more in the midrange, and I think it would probably improve the imaging, as well. Worth a try, and no disassembly required.

                Mark

                Comment


                • #9
                  Re: Question about my speakers and midrange resolution or lack of it.

                  I'll check my calculation again. I used some online calculator. I thought I was within spec but I'll check again.

                  Originally posted by WernerM View Post
                  If I had to venture a guess, I would say the biggest issue is the CTC spacing. Looks like your CTC is about 6.5-7 inches. At 23ooHz crossover, I believe the minimum, ideal would be around 3 inches CTC. You are probably getting a lot of lobing with that setup which is hurting the mid range clarity. I'm not an expert, but this would be my first guess as to the problem...

                  Comment


                  • #10
                    Re: Question about my speakers and midrange resolution or lack of it.

                    Originally posted by contoursvt View Post
                    For bracing I evenly spaced (as much as possible) two dividers with two rectangles cut out of it to sort of create an H shape, I also put a dowel right in between the little bit of wood between the cutouts of the tweeter and woofer going to the back wall because teh wood was thin. The front baffle is 1" thick, the rest is 3/4" and I opened up the back side of the woofer cutout a bit with a router.

                    I didnt use any stick on sound dampening but I did use 1 1/2" thick of rockwool to line about 3/4 of the way down either side and about half way on the front and back walls. The bottom 1/4 of the cabinet doesnt really have any dampening though.
                    Any sound from the woofer that travels to a box panel, and is reflected back, can strike the cone, and with some cones, be retransmitted out through the cone with a delay. So I try to absorb as much as possible. A long box may have standing waves in a frequency range that a small box would not. The bigger speaker may make a lot more bass, and the room may cause it to mask some of the midrange detail. You could highpass at 80 hz and compare. Are you comparing the speakers in the same room, and system? I like to really damp my speaker boxes. If there is no port to work around, I'd probably add pink fiberglass in the bottom third of the box, and add a piece of 1" eggcrate foam to sort of section off the bottom portion. Not airtight, or anything, just add a significant resistance for the soundwaves to penetrate. Parts express sells stick on damping material that I use on occasion. This would reduce the panel vibrations a little. They still vibrate, but they stop sooner. Small boxes, with small panels, are inherently stiffer, and vibrate at higher frequencies that are more easily damped. Room placement can effect things a lot. My speakers are out about 4' from the back wall. In a bigger room, I might try five or six feet.

                    Comment


                    • #11
                      Re: Question about my speakers and midrange resolution or lack of it.

                      Well I've only measured them on axis and from my seated position. Do you think I should measure differently to see if something else is going on? The usher speakers are slightly more even from but they dont vary all that much. Most of the variance is in the bass. The small speakers have smoother bass output. For some reason I'm getting much more of an upperbass suckout in the room.
                      Originally posted by billfitzmaurice View Post
                      If there is a problem it should show up on the RTA. If you can hear it, you can measure it.

                      Comment


                      • #12
                        Re: Question about my speakers and midrange resolution or lack of it.

                        I'll try adding more fill and see what happens. All else fails, I will try making a smaller cabinet and moving everything into it as a quick test. If it sounds better, I will then just finish the smaller cabinets and accept some of the bass extension loss. Right now in room response, this hits solid low 30Hz without any probem and is still fully usable at 27Hz but below that not much.

                        Originally posted by rpb View Post
                        Any sound from the woofer that travels to a box panel, and is reflected back, can strike the cone, and with some cones, be retransmitted out through the cone with a delay. So I try to absorb as much as possible. A long box may have standing waves in a frequency range that a small box would not. The bigger speaker may make a lot more bass, and the room may cause it to mask some of the midrange detail. You could highpass at 80 hz and compare. Are you comparing the speakers in the same room, and system? I like to really damp my speaker boxes. If there is no port to work around, I'd probably add pink fiberglass in the bottom third of the box, and add a piece of 1" eggcrate foam to sort of section off the bottom portion. Not airtight, or anything, just add a significant resistance for the soundwaves to penetrate. Parts express sells stick on damping material that I use on occasion. This would reduce the panel vibrations a little. They still vibrate, but they stop sooner. Small boxes, with small panels, are inherently stiffer, and vibrate at higher frequencies that are more easily damped. Room placement can effect things a lot. My speakers are out about 4' from the back wall. In a bigger room, I might try five or six feet.

                        Comment


                        • #13
                          Re: Question about my speakers and midrange resolution or lack of it.

                          Originally posted by fastbike1 View Post
                          You sure about that calc? Looks to me like the "rule of fumb" would be a CTC of ~5.75 - 5.85" @ 2300Hz. Speed of sound / CTC = XO freq or SOS / XO = CTC.
                          Yes that is the calculation for full wave, I was under the impression that half wave length spacing was better for imaging, and driver dispersion...
                          HAGD,
                          Marc

                          Even though I try to tell everyone upfront, understand that I am still a Newb. I wish the status of Seasoned Veteran/Senior Member, etc. was earned with time not posts...

                          TMWW thread

                          Maurbacs DCR Tower

                          Comment


                          • #14
                            Re: Question about my speakers and midrange resolution or lack of it.

                            Originally posted by contoursvt View Post
                            For some reason I'm getting much more of an upperbass suckout in the room.
                            I'm not surprised, judging by how far they are from the rear wall. Are you familiar with Allison Effect? You don't want the baffle 1/4 wavelength from the rear wall unless you're trying to reduce the midbass.
                            Well I've only measured them on axis and from my seated position
                            That's what counts. The smaller drivers will have wider dispersion, so they'll have better off-axis clarity, but that's only a concern if you listen to them off-axis.
                            I did use 1 1/2" thick of rockwool to line about 3/4 of the way down either side and about half way on the front and back walls. The bottom 1/4 of the cabinet doesnt really have any dampening though
                            That's thick enough, but you need full coverage.
                            I was under the impression that half wave length spacing was better for imaging, and driver dispersion..
                            Tight spacing reduces lobing, which can be an issue when the listening position is close to the speaker. The further away you are the less it matters.
                            www.billfitzmaurice.com
                            www.billfitzmaurice.info/forum

                            Comment


                            • #15
                              Re: Question about my speakers and midrange resolution or lack of it.

                              Ahah! Many thanks. I just learned a bunch of stuff

                              Originally posted by billfitzmaurice View Post
                              I'm not surprised, judging by how far they are from the rear wall. Are you familiar with Allison Effect? You don't want the baffle 1/4 wavelength from the rear wall unless you're trying to reduce the midbass.
                              That's what counts. The smaller drivers will have wider dispersion, so they'll have better off-axis clarity, but that's only a concern if you listen to them off-axis.
                              That's thick enough, but you need full coverage.
                              Tight spacing reduces lobing, which can be an issue when the listening position is close to the speaker. The further away you are the less it matters.

                              Comment

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