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  • #31
    Originally posted by Millstonemike View Post


    The OSs are 25W speakers and the amp can exceed that at 24v into 8 ohms given a sufficient input signal. Given the amp's (e.g., chip setting) stated gain of 26 dB you'll need ~.75 V rms input to get 30 W rms out. Most phones' headphone outputs are not that strong. All my PC outputs can reach 1.4 V rms so they can be used to test/confirm.
    Interesting! I've read someone said the output level on the bluetooth chip isn't so high, have you heard anything about this?

    FJ


    FJ

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    • #32
      Originally posted by Fjellhelten View Post

      Interesting! I've read someone said the output level on the bluetooth chip isn't so high, have you heard anything about this?

      FJ


      FJ
      Yes, that also seems to be an issue. The BT section seems to have low output (much like a phone's headphone out). So if you running on the integrated battery solution, you may be able to get the max power that ~12v PS will support. That would be nominally 9 W rms @ 8 ohms and 18 Wrms @ 4 ohms. Raising the PS voltage to 24 V allows four times that power. However, with the chip set at 26 dB chip gain (from Sure manual, the OEM for the KAB boards), that equates to ~20x input to output. If you have a say a 0.4 V rms input signal, you'll get 8 V rms output which equates to ~11 V peak on a sine wave - just under the upper limit of a 12 PS.. But you'll never really get to use the power available given of a 24V PS. The 2 x 30W board seems to be worse at 20 dB gain (e.g., 10x gain).

      I had a wired TPA3116 based amp set at 26 dB gain and couldn't get my phone to drive it anywhere near max volume (but my PC and laptop putting out 1.4 Vrms could). So I front-ended the amp with the Sure headphone amp. That adds 9 or 15 dB gain (dip setting) allowing the lower phone signal to drive the chip to max power out. But that won't solve the BT issue on the integrated KAB-250.

      If your building an indoor table top type system, the stock KAB may be fine. If you looking for outdoor, pool party type output, you need to go separate components, amp, headphone amp and BT module with the BT output and any wired input feeding the headphone amp. The only issue with that is the Sure BT module is spec.'d for 12V only. So for that module, you would need to drop the 24V supply down to 12V using LM7812 linear regulator.

      You could try and change two SMT resistors on the KAB to select the next higher chip gain at 32 dB (.e.g., 40x). But other amp's doing this seem to have more noise.depending the supplier.

      Comment


      • #33
        Originally posted by Millstonemike View Post
        Yes, that also seems to be an issue. The BT section seems to have low output (much like a phone's headphone out). So if you running on the integrated battery solution, you may be able to get the max power that ~12v PS will support. That would be nominally 9 W rms @ 8 ohms and 18 Wrms @ 4 ohms. Raising the PS voltage to 24 V allows four times that power. However, with the chip set at 26 dB chip gain (from Sure manual, the OEM for the KAB boards), that equates to ~20x input to output. If you have a say a 0.4 V rms input signal, you'll get 8 V rms output which equates to ~11 V peak on a sine wave - just under the upper limit of a 12 PS.. But you'll never really get to use the power available given of a 24V PS. The 2 x 30W board seems to be worse at 20 dB gain (e.g., 10x gain).

        I had a wired TPA3116 based amp set at 26 dB gain and couldn't get my phone to drive it anywhere near max volume (but my PC and laptop putting out 1.4 Vrms could). So I front-ended the amp with the Sure headphone amp. That adds 9 or 15 dB gain (dip setting) allowing the lower phone signal to drive the chip to max power out. But that won't solve the BT issue on the integrated KAB-250.

        If your building an indoor table top type system, the stock KAB may be fine. If you looking for outdoor, pool party type output, you need to go separate components, amp, headphone amp and BT module with the BT output and any wired input feeding the headphone amp. The only issue with that is the Sure BT module is spec.'d for 12V only. So for that module, you would need to drop the 24V supply down to 12V using LM7812 linear regulator.

        You could try and change two SMT resistors on the KAB to select the next higher chip gain at 32 dB (.e.g., 40x). But other amp's doing this seem to have more noise.depending the supplier.
        Thanks for filling in on this! I don't have much knowledge on the bits&pieces of chip amps so this is golden!

        The Sensations will sit in my parents house and will certainly be the indoor tabletop style speakers. I think they will mostly use the BT interface, and the amp will be wired, not battery powered. Guess I'll have to hear the output level once the amp arrives I hope I don't have to do any changes to the amp though

        I'm playing with the idea of implementing a switch on the back making it possible to switch between using the internal amp or external amp connected to traditional speaker terminals...

        FJ

        Comment


        • #34
          Originally posted by Fjellhelten View Post
          I'm playing with the idea of implementing a switch on the back making it possible to switch between using the internal amp or external amp connected to traditional speaker terminals...

          FJ
          That may be an excellent idea, especially if you have another amp to test / compare the basic speaker performance and the KAB solution.

          Comment


          • #35
            Originally posted by Millstonemike View Post

            That may be an excellent idea, especially if you have another amp to test / compare the basic speaker performance and the KAB solution.
            Yeah, one amp for daily easy BT use, as well as being able to get the most out of the speakers from an external quality amp Just ordered a 6pole two circut switch for the job

            Comment


            • #36
              Having assembled the crossover, recieved both tweeter and woofer, and completed the cabinet constriction, I couldn't resist the temptation of putting the speedsters together to have a listen. (A dangerous thing of course.. I MUST summon strength to take them apart soon for finishing😄)

              I really don't know what to say. Its difficult to wrap my head around how a speaker this compact can produce the sound they do. Bass is superb. In room measurements show -3dB in the low 40's, and it very much sounds so. Mids and highs are pleasant and balanced and mates well with the over all sound. I am extremely happy with the way they sound. I'm running them off a Cambridge Azur 840A amp. Turns out I hit spot on recalculating port length, as Vb is precisely 55Hz. I was crossing fingers on this, because the front opening on the port is somewhat untraditional as far as calculating the end correction value..

              Of course, they need a bunch of watts thrown at them, being low sensitivity. And its visible that the woofers are working hard when playing low frequencies relatively loud. No party speakers as far as SPL, but that was never their intended role either.

              Absolutely love them! HUGE thanks to Mr Paul Carmody for designing and putting the work out there for others to enjoy!




              The KAB-250's have arrived too, so I'll have to play around with this later this week before they go into the OS's. Hope it sounds good! The OS's will be matte white to match the interior of their new home😊

              FJ

              Comment


              • #37
                Looking great!!
                Isn't it about time we started answering rhetorical questions?

                Paul Carmody's DIY Audio Projects
                Twitter: @undefinition1

                Comment


                • #38
                  Originally posted by Paul Carmody View Post
                  Looking great!!
                  Thanks Paul! These speakers deserve a smooth and perfect finish to match their performance. Hoping to put on a good looking finish pretty soon

                  Just ordered a 24V PS for the KAB-250. I'm still waiting for the OS tweeters and crossover parts, as Meniscus forgot to pack them with the original shipment.. They sent new parts and now the tracking says that the shipment hasn't been seen since in China(!!) on 03/05.... Chicago-China-Norway doesnt seem to be a very practical route.

                  Maybe some chinese dude has half a OS kit now

                  Comment


                  • #39
                    On this build I had to chamfer the back of the driver holes after the box was assembled. I had to figure out how to do this in a practical way, and this is what I did:

                    I used my dremel with a router bit, and made a jig out of some scrap metal I had laying around.

                    I used the woofer recess as a guide for the dremel jig and free handed the rest.

                    Did this to both the Speedsters and the OS's

                    Im guessing pics explain better than me :



                    FJ


                    Comment


                    • #40
                      I admire your tenacity! That is a slick solution to this dilemma. I do have a question though- Is that an 1/8" shaft Dremel-specific router bit?
                      I might have to go pick one of those up, as I didn't know they existed. Another option would be a rasp or rotozip spiral-blade, but likely not as efficient as what you have there.

                      Later,
                      Wolf
                      "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                      "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                      "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                      "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                      *InDIYana event website*

                      Photobucket pages:
                      http://photobucket.com/Wolf-Speakers_and_more

                      My blog/writeups/thoughts here at PE:
                      http://techtalk.parts-express.com/blog.php?u=4102

                      Comment


                      • #41
                        Originally posted by Wolf View Post
                        I admire your tenacity! That is a slick solution to this dilemma. I do have a question though- Is that an 1/8" shaft Dremel-specific router bit?
                        I might have to go pick one of those up, as I didn't know they existed. Another option would be a rasp or rotozip spiral-blade, but likely not as efficient as what you have there.

                        Later,
                        Wolf
                        Thanks Wolf,

                        Yeah the bit is a standard 1/8 inch shaft meant for dremel type machines. I think I bought it on ebay a long time ago. Couldn't find router bits in any near stores..

                        FJ

                        Comment


                        • #42
                          Some progress:

                          I got hold of two acryl plates to make terminal/connector panels on the Sensations.

                          I drilled holes for connectors, speaker terminals, volume knob and LED lights. The cutout for the switch was made using a router table and a sharp blade.

                          The acryl is white with a black top, ment for engraving. I'm going to have it engraved (aux, vol, 24V DC, etc) making it easier for my folks to use them.


                          FJ

                          Comment


                          • #43
                            Hey guys!

                            I wasn't quite happy with the back plates the way they were, so I decided to round off the corners and have them recessed into the back. And I had them engraved as well. Turned out pretty nice

                            The boxes have been finished with matte white plasti dip (almost done, just need some more on the baffles) Im really happy with the matte white against the mirror gloss back plates

                            FJ

                            Comment


                            • #44
                              Originally posted by Fjellhelten View Post
                              Hey guys!

                              I wasn't quite happy with the back plates the way they were, so I decided to round off the corners and have them recessed into the back. And I had them engraved as well. Turned out pretty nice

                              The boxes have been finished with matte white plasti dip (almost done, just need some more on the baffles) Im really happy with the matte white against the mirror gloss back plates

                              FJ
                              They look great. I think you'll get a lot of comments along the lines: "Where did you buy those?"

                              Comment


                              • #45
                                Someone else used PlastiDip to 'paint' their cabs on here at one time, and the results weren't favorable. The finish ended up flaking off since it didn't adhere very well.

                                Now- if you used actual spray paint from PlastiDip brand name, then I doubt you'll have issues.

                                They look really nice, BTW!
                                Wolf
                                "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                                "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                                "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                                "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                                *InDIYana event website*

                                Photobucket pages:
                                http://photobucket.com/Wolf-Speakers_and_more

                                My blog/writeups/thoughts here at PE:
                                http://techtalk.parts-express.com/blog.php?u=4102

                                Comment

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