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  • Discussion - What can i improve on a small build?

    I will start off by saying yes im trying to improve on below 2 iinches driver sizes and its not everyones cup of tea.

    Lately i've been listening to the mini ghettoblaster a fair bit, ocassionally maxing the volume and positioning it around the house up against walls, in the middle of open areas etc. And come up with a few points that this little speaker in the right settings has a nice amount of bass for a 1.5inch driver and can handle anything i throw at it. Which made me wonder how much more could i refine, improve etc.

    https://techtalk.parts-express.com/f...ster-half-size

    i've sourced a different amp, which apparently from a 5v supply can put out 2x10watts and still allow me to tweak the onboard EQ/DSP and other settings, providing i have the right version of Bluesuite. I did mess around with the EQ on poweramp (phone) to try emulate a bass shelf as well and it was slightly noticable.

    Also from the slow boat is a 5v spectrum analyzer which i'm not sure how to get the input signal to yet considering these amp boards are literally a BT chip on a basic board, but hoping i could use the positive lead to each speaker. I've got an arduino and a strip of LED's as well, which i was wanting to experiment with, but not sure if this will be too much draw on the batteries.

    So as i'm going to swing for the fences with this one, whats the views on

    1. Box tuning
    2. PR tuning
    3. EQ tuning
    4. Other

    So far what was used on the previous build, was 1x DMA45 driver paired with a ND90-PR in a 0.015cuft enclosure for each side. This was getting an F3 of around 92hz, F6 - 87hz, F10 82hz, the PR is sitting F3 86hz, F6 - 80hz, F10 72hz (if this is actually how you are meant to read this graph). So the inital thoughts where do i try and reduce the internal volume, which lifts the drivers tuning into the 100's, but then adding lets say 7g's of weight which decreases the PR's range almost 10hz across the board, where an F10 would get into the mid to high 60's, which actually drops the drivers tuning as well, but goes to having a slight dip in the mid 100's.

    I realize as well, i'm trying to push something that no one really cares about, but i find this quite interesting and most will know i was fascinated with building something that could compete with my folks soundlink mini, as well as doing something extra with different forms of electronics......And it looks really cool in my study on the wall with the rest of my setup.

    Attached Files

  • #2
    Fyi I obviously fall under the "commoner" banner
    Attached Files

    Comment


    • #3
      Hey 3rutu5,

      We've chatted about this before, but I have 3 possible ideas.

      First, I just think you need a little more wattage to your drivers. It sounds like you've got that covered maybe with the new amp setup. But I'm just suspicious of any tiny board that claims to turn 5 volts into a decent audio wattage output. In my experience they just don't seem to provide the 'oomph' to the amp to create suitable bass. Maybe the new amp you have coming will be a better option, but with the DMA45, I've used PE's little all-in-one 2x30 watt per channel amps which with 12 volts may create a 10-11 watt real-world output. I think one of the secrets to making these little buggers sing down low is a suitable amp and higher voltage/amperage. I can't prove that scientifically, but it's just my Ear-World-Experience (TM) .

      Secondly, maybe the ND65 passive radiator could provide a bit more low end? I haven't modeled the ND90 based PR's with these small buggers, but I was pretty happy with the ND65 based PR's.

      And the third thing which I guess you've already got covered is to boost the bass a bit. Seems like you can do that with the DSP built in on the board? Like I mentioned up there /\ I used this amp board: Stereo 4.2 Bluetooth 2 x 30W Amp Board with Volume Control, USB Reader/Charger, and IR Remote (parts-express.com)​ and it can really push the volume up without being strained... it provides a clean signal to the speakers. It also has a bass-boost setting on the EQ which actually works well with the small Visaton and DMA drivers at low/med volumes. It gives a much better 'full' sounding low end.

      If you want to get a signal easily to run a spectrum analyzer off of, check out this amp board. It's not a PE product yet I don't think so I won't link to another website, but instead my video review of it: https://www.youtube.com/watch?v=yegUiYLHskA it's the TPA3110 bluetooth only amp board. You can easily hack the daughter board to get a pretty hot audio L and R signal to feed to a spectrum analyzer. They're only 5 or 6 US dollars each too.

      ...That sounds like a really cool build by the way... tiny speaker and tiny spectrum analyzer... what a cool combination!

      BTW, here is another video I did where I assemble some SA's and VU meters, and near the end demo a few of the other SA's I've used over the years. It's a long and probably boring video, but here is a link to the good part at the end: https://youtu.be/GKKgGvKA_iA?t=1574

      Basically, I think the low-powered amp boards just don't provide enough low end to do the job. If you run those same little speakers off of one of the 15-30 watt boards that I mentioned, I actually think you'd get a better low end. Doesn't seem exactly logical but...
      ...Awhile back I did a radio with both the Visaton BF37 and DMA45 drivers and I said the DMA sounded quite a bit better to me, even though the specs and FR graph suggested they should be equal or maybe even the Visaton should have a touch more bump, but in my experience, it didn't. I preferred and still prefer the DMA45 by a good margin. Ears over Graphs for me. I think the really low-powered Class-D boards cut the bass also.

      I know it's not everyone's cup of tea, but I love seeing this stuff, the ingenuity it takes to first design, then troubleshoot, then try ad fit all of this stuff into an enclosure is just crazy, please post pics as you go.

      TomZ

      Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
      *Part 2 *Gluing multiple curved laminations of HDF

      Comment


      • #4
        I've been on the small bluetooth kick myself. I find small speakers shrill at high volumes. I added a small .27mh iron core inductor to each speaker. Makes for a much better sound imo.

        Comment


        • 3rutu5
          3rutu5 commented
          Editing a comment
          Nice, did you use a similar bt amp board to me? Well the smaller ones (qcc/CSR types)

        • Jake
          Jake commented
          Editing a comment
          This one is the csr, but I've used the dw-ct114, and the xh a158. All 5v, and offer a slightly different sound.

        • 3rutu5
          3rutu5 commented
          Editing a comment
          I've only really used the qcc3003 and two CSR ones, find the qcc actually has a bit more volume to it. Not bad little low powered units albeit a little small to solder onto for me. I quite like the look of the blue one you have there, looks similar to some YT ones that inspired me to make the quarantineee

      • #5
        Originally posted by Jake View Post
        I've been on the small bluetooth kick myself. I find small speakers shrill at high volumes. I added a small .27mh iron core inductor to each speaker. Makes for a much better sound imo.
        what does the inductor do for this? fix up the shrill at the high volumes?

        I find it quite fun and challenging. I thought my boozetooth speakers sounds ok, same with the quareentee but that mini ghettoblaster difference was night and day, proper stereo and what ever else i managed just sounded much better. Could be the fact im only putting 5 watts per channel into them so i dont hit those higher volumes you mention yet.

        Comment


        • Jake
          Jake commented
          Editing a comment
          Yes, the inductor reduces some of the higher frequency, smoothing the sound at higher volumes, and adding some baffle step.

      • #6
        Originally posted by tomzarbo View Post
        Hey 3rutu5,

        We've chatted about this before, but I have 3 possible ideas.

        First, I just think you need a little more wattage to your drivers. It sounds like you've got that covered maybe with the new amp setup. But I'm just suspicious of any tiny board that claims to turn 5 volts into a decent audio wattage output. In my experience they just don't seem to provide the 'oomph' to the amp to create suitable bass. Maybe the new amp you have coming will be a better option, but with the DMA45, I've used PE's little all-in-one 2x30 watt per channel amps which with 12 volts may create a 10-11 watt real-world output. I think one of the secrets to making these little buggers sing down low is a suitable amp and higher voltage/amperage. I can't prove that scientifically, but it's just my Ear-World-Experience (TM) .

        Secondly, maybe the ND65 passive radiator could provide a bit more low end? I haven't modeled the ND90 based PR's with these small buggers, but I was pretty happy with the ND65 based PR's.

        And the third thing which I guess you've already got covered is to boost the bass a bit. Seems like you can do that with the DSP built in on the board? Like I mentioned up there /\ I used this amp board: Stereo 4.2 Bluetooth 2 x 30W Amp Board with Volume Control, USB Reader/Charger, and IR Remote (parts-express.com)​ and it can really push the volume up without being strained... it provides a clean signal to the speakers. It also has a bass-boost setting on the EQ which actually works well with the small Visaton and DMA drivers at low/med volumes. It gives a much better 'full' sounding low end.

        If you want to get a signal easily to run a spectrum analyzer off of, check out this amp board. It's not a PE product yet I don't think so I won't link to another website, but instead my video review of it: https://www.youtube.com/watch?v=yegUiYLHskA it's the TPA3110 bluetooth only amp board. You can easily hack the daughter board to get a pretty hot audio L and R signal to feed to a spectrum analyzer. They're only 5 or 6 US dollars each too.

        ...That sounds like a really cool build by the way... tiny speaker and tiny spectrum analyzer... what a cool combination!

        BTW, here is another video I did where I assemble some SA's and VU meters, and near the end demo a few of the other SA's I've used over the years. It's a long and probably boring video, but here is a link to the good part at the end: https://youtu.be/GKKgGvKA_iA?t=1574

        Basically, I think the low-powered amp boards just don't provide enough low end to do the job. If you run those same little speakers off of one of the 15-30 watt boards that I mentioned, I actually think you'd get a better low end. Doesn't seem exactly logical but...
        ...Awhile back I did a radio with both the Visaton BF37 and DMA45 drivers and I said the DMA sounded quite a bit better to me, even though the specs and FR graph suggested they should be equal or maybe even the Visaton should have a touch more bump, but in my experience, it didn't. I preferred and still prefer the DMA45 by a good margin. Ears over Graphs for me. I think the really low-powered Class-D boards cut the bass also.

        I know it's not everyone's cup of tea, but I love seeing this stuff, the ingenuity it takes to first design, then troubleshoot, then try ad fit all of this stuff into an enclosure is just crazy, please post pics as you go.

        TomZ
        sorry Tom, i can never seem to find anything i post half the time. Real pain in the you know what.

        I also a little hestiant in the claims of a $15-20AUD board that boasts the world. Whatever my 5v Qcc3003 is doing i like it, but i do have to boost it to 6.5v to get that, but this new one is saying that it can get more with less which does sound bogus. Good thing is i bought some of these test board clamps which have 4 pogo pins each so i can clip it to the board and test without soldering. That was one of the major issues with the other build was once i soldered the leads on i could connect to the 1mm spacing 8 pins to program it. I also messed up, it isnt 10watts per channel, its 8watts. I've attached the picture, on the left between the momentary swtiches and the blue BT chip, you'll see those tiny solder points, my hands arent that skills considering this board is tiny and those points tinier. I did do that massive boozetooth where i used a 2x50 watt ali class D, 3x 16350 batteries and a ND65, which i stuffed up as i didnt use a spst switch so the unit stays active all the time draining the battery, time to repurpose the power supply from it maybe.

        I do have that amp you posted thanks to you and it slightly shorter in length than the other one i have, to be honest i dont know why i havent given it a go yet, especially seeing it has an input jack. I did model the ND65PR as well, on paper it looked like i needed 2 of them with some additional weight to come close to the single ND90PR, it was a little behind, are you thinking that little speaker will have an easier time moving the smaller PR?
        Attached Files

        Comment


        • #7

          Okay, so you do have one of those all in one amp boards with the USB and remote card control. They really are suited to the DMA45 type drivers. They provide just a touch more clean output than the drivers can take without breaking up, which means that the driver is pushed to it’s limit, not the other way around. It’s hard to know what’s the issue with a particular design if the amp isn’t producing enough clean output.

          Regarding the ND65 PR, I used it with one DMA 1 to 1 and it really performed well. Here is the cubic volume for one DMA45 and a ND65 PR: “It looks to be about 0.536 Liters or 32.81 cu. in. at this point.” That point in that thread: https://techtalk.parts-express.com/f...69#post1436569

          I thought it did rather well and although there were compromises, it produced enough low end to be satisfying close range. Very similar to a Bose Soudlink Mini in sound. It’s not that I don’t think a single DMA45 wouldn’t have the oomph to work well with a ND90 PR, I just happened to use the ND65PR and it worked well, sounded punchy.

          I don’t know if your box size is different enough to create an issue with excursion on the PR. In practice, it has more than enough sweep to keep up with the DMA45.

          I’m going to be working on my third and last Small Bluetooth speaker thingy, the “Tiny Tom Bluetooth Radio” basically the same as the other ones, just a slightly different arrangement of parts. The amp board with the Bluetooth daughter board is so easy to hack for a VU meter or SA that it’s almost too easy. The other one with the USB would be a lot harder, and it would be variable based on volume probably too. Decisions.

          You know, the problems you're having are because you're willing to go the extra, EXTRA mile to keep things SUPER tiny, that means some sacrifices I don't have to make because I'm just trying to keep things Miniature. You're in a whole different league with that microscopic stuff. My fingers are WAY to fat for that. Keep going though!

          I actually just received 2 days ago a Bose Soundlink Mini used from Ebay for comparison to the project I'm going to build... it will also be a YouTube video so it's worth spending the money on it to make the video better. That thing is TINY! Amazing!


          TomZ
          Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
          *Part 2 *Gluing multiple curved laminations of HDF

          Comment


          • #8
            I'm not sure I have problems as such, as it does sound pretty good as is, I just want more haha..it's like the time Chris sized that BSC for my tectonics and it went next level. Bit of a downer you guys are on the opposite side of the planet as a YouTube recording doesn't do it justice.

            Good thing is, if I do go 12v I'm not restricted on only using 4ohm drivers as I have a couple of DMA-8s in a box, but will need to get some PRs. As I'm waiting for a month of the spectrum analyzer I can put some research into how I'm going to get everything into the box.

            I know you said last iteration of the tiny tom, but I feel with these you get caught in a loop trying to improve each time, well at least that's what I seem to be doing.

            With this one I was planning to not 3d print the fixed in place switches and instead sourced some slide spsts that had a 6mm long lever. And If I use that amp I linked I could use the play/pause buttons with the momentary switches. Probably break but would look cool hahs

            Comment


            • #9
              I've got a nice controller board for the JAB4 board that makes it a stereo 2-way amp with Bluetooth audio input. It controls the DSP on the JAB4 to provide crossovers, bass enhancement (real boost and a psychoacoustic "fake bass" algorithm), plus lots of filters for EQ. The controller board is the Adafruit QT Py ESP32C3, which is very small (22mm by 18mm) and can connect to a piggyback LIPO charger. With this controller, you can control the volume, crossover, bass enhancement and EQ from a cell phone app. The JAB4 might be bigger than what you want but getting rid of the passive crossover might give you enough room. I haven't written up the details yet, but they will show up in this article. I had to set this aside for a while because the ESP32C3 only supports Bluetooth BLE for control, and I was using Bluetooth classic. But that code has been re-written. I still have more testing to do, but it's looking promising...

              Update: it's been so long that I worked on this project that I forgot that I had added the Analog Devices Dynamic Bass algorithm. It's there in the DSP, but I need to add that to the app to control it from the cell phone. It can be controlled from the Nextion display shown in the article, but I'll add it to the Android code, also. Dynamic Bass is how those little commercial Bluetooth speakers usually deal with bass.
              Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

              Comment


              • #10
                Originally posted by tomzarbo View Post

                [FONT=Calibri]I’m going to be working on my third and last Small Bluetooth speaker thingy, the “Tiny Tom Bluetooth Radio” basically the same as the other ones, just a slightly different arrangement of parts. The amp board with the Bluetooth daughter board is so easy to hack for a VU meter or SA that it’s almost too easy. The other one with the USB would be a lot harder, and it would be variable based on volume probably too. Decisions. !

                TomZ
                Which ones were these? The nd65/dma etc? I tried searching the name and got inception back to here and the cool ones you did that made me think to go the DMA over the viston drivers

                Comment


                • #11
                  Originally posted by 3rutu5 View Post

                  Which ones were these? The nd65/dma etc? I tried searching the name and got inception back to here and the cool ones you did that made me think to go the DMA over the viston drivers
                  Yes you've got it. I don't remember what I called that radio, or if I even did name it. It used the DMA45 and ND65 PR with the curved top. Here is where the build starts part way through the thread: https://techtalk.parts-express.com/f...21#post1436521

                  Sorry for the confusion on the Tiny Tom Table Radio title, that's what I intend to call it now that I have a YouTube channel and you need a catchy video title, not just "Radio #14" or something stupid like that.

                  Click image for larger version

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                  TomZ
                  Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                  *Part 2 *Gluing multiple curved laminations of HDF

                  Comment


                  • #12
                    Looking at doing a smaller one which is taking parts from the 2.1ch tang band i was doing. those speaker drivers on their own do an ok job, so not much thought required just not going to use that 2inch micro sub.

                    Although if i ever wanted to get close to the size of the bose soundlink mini, picking the Tang Band T1-1828SD's would be a worthy competitor.

                    Comment

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