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Small BT boombox build - help please

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  • Chris Roemer
    replied
    Box size requirements are driven by Vas and Qts.
    Given 2 drivers of equal Vas (let's just say 0.50cf), one with a higher Qts will need a larger box.
    With a Qts of 0.40, driver "A" generally likes a (vented) box around 0.50cf (close to Vas), while driver "B" (with a Qts of 0.50) wants more like 0.80cf.

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  • 3rutu5
    replied
    I'll admit it does get a bit confusing sometimes. The relationship between VAS and VB seems to be one open to interpretation. The ND91's not have a VAS of 0.05cuft, yet works really well in the passive aggressives in a 0.04 flat pack box.

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  • 3rutu5
    replied
    Originally posted by Chris Roemer View Post
    I can't tell w/out knowing your port ID. If 20mm, then it'll tune your box to 70Hz.
    In the last few yrs the specs for that driver changed here on site. Only the Vas changed, but it went up from 0.02cf to 0.03cf (a 50% increase).
    Your box SEEMs small (at a Vas of 0.03). If your size is fixed, I'd tune it a bit higher. If your port is 20mm, I'd go 125mm for length (Fb in the mid 70s).
    Yes it is 20mm, I originally modelled 0.03, but when you put the BSC, amp, batteries and BT board you really don't have much of each enclosure to fit either a port or have any room internal. So it is rebuilt using the rest of the scrap pine I had which happens to be internally 0.095 overall, or the 0.045 I assumed (once I put the dividing wall in. 70hz seems to model ok, I think it gave mid 60's at F3. I just need to find an elbow joint for the electrical conduit so there is a bit of space to the opening of the port

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  • Chris Roemer
    replied
    I can't tell w/out knowing your port ID. If 20mm, then it'll tune your box to 70Hz.
    In the last few yrs the specs for that driver changed here on site. Only the Vas changed, but it went up from 0.02cf to 0.03cf (a 50% increase).
    Your box SEEMs small (at a Vas of 0.03). If your size is fixed, I'd tune it a bit higher. If your port is 20mm, I'd go 125mm for length (Fb in the mid 70s).

    Leave a comment:


  • 3rutu5
    replied
    Originally posted by Chris Roemer View Post
    Don't "guess" !
    Look at the PDF of the plots. Looks like it's pretty much done by 4kHz.
    I've abandoned that train of thought, going to use those ND65-4 for good and not evil. 0.045cuft (each) tuned to 70hz and port apparently 150mm, but would like you input on the port if possible, already had the BSC sorted.

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  • Chris Roemer
    replied
    Don't "guess" !
    Look at the PDF of the plots. Looks like it's pretty much done by 4kHz.

    Leave a comment:


  • 3rutu5
    replied
    Originally posted by Chris Roemer View Post
    To ME, 264-1064 (4ohms, glass cone) looks a bit better than 264-1062 (8ohms, paper cone).
    A bit flatter. A bit higher sensitivity. Probably able to play a bit lower. Still, they BOTH only have about 2-1/2mm Xmax.
    True, I'm guessing these 264-1600 don't go higher enough on their own to be able to function without a tweeter

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  • Chris Roemer
    replied
    To ME, 264-1064 (4ohms, glass cone) looks a bit better than 264-1062 (8ohms, paper cone).
    A bit flatter. A bit higher sensitivity. Probably able to play a bit lower. Still, they BOTH only have about 2-1/2mm Xmax.

    Leave a comment:


  • 3rutu5
    replied
    Any thoughts on whether the 3.5" peerless could act as a stand alone full range?

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  • 3rutu5
    replied
    Originally posted by STIchris722 View Post

    Well you definitely have me beat on your last build! I have always wanted to try the succession of cuts so that the wood can be folded as you did! I really like what you did with that. Hopefully you don't think I was bashing you earlier; I was simply trying to give you some ideas to re-route your current build a little bit. From what I can tell, you know what you are doing, but are rather looking for some input from the community. There is no harm in that by any means. If you don't mind me asking, how did that little guy turn out SQ-wise?

    I spent some time last evening researching some ideas/parts for your current build, but was striking out with the new Dayton DSP BT boards. They make a 2x50 @4ohms and a 1x100 @4ohms that I believe can link together, but don't play well with a battery board (I believe). There was also something about the boards losing their BT function? I couldn't find all the information on it and @4am my brain stopped working! keep us posted on what you come up with.

    Cheers,
    Chris
    I would say know what I'm doing loosely I've had some good help along the way from members of this forum to take my builds to.the next level. I don't take any responses on here as bashing as I'm a beginner. With those peerless I saw "half space" and massive magnets and probably got caught up thinking small box over functionality.

    sound wise the unit turned out well, doesn't distort and can handle the bass extremely well. I've use those drivers on most projects and they have a love hate relationship with most people, but with me I think they do a great job. If I could make that unit again I would have enclosures of 0.17-0.18cuft as I know it models a FS of 58hz and sound a bit better again I made some PC/Bookshelf speakers doing that and you can notice the difference

    edit...and also not have the ports on the front facing, i think it works\sounds better with ports at the rear.
    Last edited by 3rutu5; 01-22-2020, 05:00 AM.

    Leave a comment:


  • Millstonemike
    replied
    Originally posted by STIchris722 View Post

    Well you definitely have me beat on your last build! I have always wanted to try the succession of cuts so that the wood can be folded as you did! I really like what you did with that. Hopefully you don't think I was bashing you earlier; I was simply trying to give you some ideas to re-route your current build a little bit. From what I can tell, you know what you are doing, but are rather looking for some input from the community. There is no harm in that by any means. If you don't mind me asking, how did that little guy turn out SQ-wise?

    I spent some time last evening researching some ideas/parts for your current build, but was striking out with the new Dayton DSP BT boards. They make a 2x50 @4ohms and a 1x100 @4ohms that I believe can link together, but don't play well with a battery board (I believe). There was also something about the boards losing their BT function? I couldn't find all the information on it and @4am my brain stopped working! keep us posted on what you come up with.

    Cheers,
    Chris
    Dayton has new battery boards in 3S and 5S versions (3 cells and 5 cells). The newer battery management modules do not depend on the Dayton 2x30/50 series amps for any functionality (as did the earlier 3S boards - battery charge current limit, IIRC). The new boards can be used with any amp and charger (wall wart). So, if you want a 2.1 amp your good with the new battery boards. And the 5S battery module will give you 21 V on portable power. That's over 3 times the W rms into the drivers compared to the 3S battery modules.

    A larger NPE cap (non-polarized electrolytic capacitor) in series with a driver will give you a 1st HP in the lower frequencies. Larger NPE's are pretty cheap compared to the film and metal XO caps. .For example, a 200 uf NPE in series with a 4 ohm driver will give you a HP Fc at ~200 Hz.

    Leave a comment:


  • STIchris722
    replied
    Originally posted by 3rutu5 View Post

    Cheers.

    honestly i have already built something where i used the Dayton v230 board and pretty happy with it. I looked at the battery boards for this build, just havent added it yet.

    http://techtalk.parts-express.com/fo...3rutu5-boombox

    A while ago i bought the 2.1 amp and was just going to use it having a go at a 2.1 portable setup, but doesnt really sound like it has enough power to move those drivers @ 12v and the smaller ones cant really model as low as what i thought, so consider this idea tanked. Around the same time i sourced from china 2x 3S BMS a 5v bluetooth receiver board and a voltage step down in anticipation that i was actually going to use the 2.1 as a portable device.

    I have always been facinated by the tiny setups that can provide a bit of a hit. I just need to keep on reading and having a crack and hopefully one day i come across something that is worth while
    Well you definitely have me beat on your last build! I have always wanted to try the succession of cuts so that the wood can be folded as you did! I really like what you did with that. Hopefully you don't think I was bashing you earlier; I was simply trying to give you some ideas to re-route your current build a little bit. From what I can tell, you know what you are doing, but are rather looking for some input from the community. There is no harm in that by any means. If you don't mind me asking, how did that little guy turn out SQ-wise?

    I spent some time last evening researching some ideas/parts for your current build, but was striking out with the new Dayton DSP BT boards. They make a 2x50 @4ohms and a 1x100 @4ohms that I believe can link together, but don't play well with a battery board (I believe). There was also something about the boards losing their BT function? I couldn't find all the information on it and @4am my brain stopped working! keep us posted on what you come up with.

    Cheers,
    Chris

    Leave a comment:


  • 3rutu5
    replied
    Originally posted by STIchris722 View Post
    While I realize everyone has a different method of accomplishing things and their designs will vary from person to person, I am having a very difficult time with this build. This is no knock on the OP. If you do continue down the road you have chosen, I would highly recommend a HP filter for the 2" drivers as the Xmax is going to run out quickly at 120Hz as you have listed. Also if you do use this method, DEFINITELY put those in a separate sealed chamber from the other LF driver. Just my $0.02

    I can see a few different methods to accomplish a BT Boombox, but not utilizing the components you have listed. Again not coming down on you 3rutu5

    I personally built a BT Boombox using full range drivers with a single 2 channel blue tooth amplifier board from Dayton. Dayton also provided the two (2) battery boards I installed within the box.

    Click image for larger version

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    Options:
    1. I would advise using a full range method such as above.
    2. Use a 2 way method with a dedicated mid range driver and tweeter and passive crossover
    3. use a 2.1 method utilizing Dayton's new boards they just released: two (2) full range drivers and a small subwoofer
    4. use a 2.1 method with a 2 way (mid range driver and tweeter and passive crossover) and a separate amp for a small subwoofer.

    There is no order to the four (4) methods listed above. Those would be my recommendations though. Take it with a grain of salt.
    Cheers.

    honestly i have already built something where i used the Dayton v230 board and pretty happy with it. I looked at the battery boards for this build, just havent added it yet.

    http://techtalk.parts-express.com/fo...3rutu5-boombox

    A while ago i bought the 2.1 amp and was just going to use it having a go at a 2.1 portable setup, but doesnt really sound like it has enough power to move those drivers @ 12v and the smaller ones cant really model as low as what i thought, so consider this idea tanked. Around the same time i sourced from china 2x 3S BMS a 5v bluetooth receiver board and a voltage step down in anticipation that i was actually going to use the 2.1 as a portable device.

    I have always been facinated by the tiny setups that can provide a bit of a hit. I just need to keep on reading and having a crack and hopefully one day i come across something that is worth while.

    thanks for the responses guys, much appreciated.


    Leave a comment:


  • STIchris722
    replied
    While I realize everyone has a different method of accomplishing things and their designs will vary from person to person, I am having a very difficult time with this build. This is no knock on the OP. If you do continue down the road you have chosen, I would highly recommend a HP filter for the 2" drivers as the Xmax is going to run out quickly at 120Hz as you have listed. Also if you do use this method, DEFINITELY put those in a separate sealed chamber from the other LF driver. Just my $0.02

    I can see a few different methods to accomplish a BT Boombox, but not utilizing the components you have listed. Again not coming down on you 3rutu5

    I personally built a BT Boombox using full range drivers with a single 2 channel blue tooth amplifier board from Dayton. Dayton also provided the two (2) battery boards I installed within the box.

    Click image for larger version

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Views:	184
Size:	200.0 KB
ID:	1429831 Click image for larger version

Name:	20180729_165331_resized[5942].jpg
Views:	175
Size:	245.7 KB
ID:	1429832

    Options:
    1. I would advise using a full range method such as above.
    2. Use a 2 way method with a dedicated mid range driver and tweeter and passive crossover
    3. use a 2.1 method utilizing Dayton's new boards they just released: two (2) full range drivers and a small subwoofer
    4. use a 2.1 method with a 2 way (mid range driver and tweeter and passive crossover) and a separate amp for a small subwoofer.

    There is no order to the four (4) methods listed above. Those would be my recommendations though. Take it with a grain of salt.

    Leave a comment:


  • 3rutu5
    replied
    i havent really thought about it before, but those designs with PR's in the 0.04cuft boxes seem like a proven design that would meet the size requirements, albeit with all the parts may get a bit expensive. Maybe a design using 1x FR driver in each with a 3.5" Peerless PR, I have done some googling and seen the passive aggressives, bantams and heliums, which all seem to have the driver, tweeter deal, which all look awesome, but any floating around that i may not have the name of that use on the 1x driver\PR combo with maybe a BSC? i'm thinking of dropping the sub idea, too hard to get everything into something less than a 0.1cuft total enclosure.

    Leave a comment:

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