Cnc Portable Fullrange Speaker

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Hi all,

This is my first post on diy audio and i would like to share my project, I bought a cnc router not to long ago and have always been interested in music and audio reproduction, So i thought i'd start off by making a small portable speaker for my workshop. I'd also like to gain some knowledge on cabinet design as i'm not to happy with end results that i have from what i have made, the sound is a bit flat in the lower mids (could the drivers need to be run in if new and would that help certain frequencies?) or is this to be expected from a small driver?


I bought two Vifa ne123w 04 drivers a year ago or so, below is the link to the specs

http://www.falconacoustics.co.uk/downloads/Vifa/NE123W-04.pdf


I used an online cabinet calculator to design a vented cabinet, which i then entered all the parameters of the driver into to get my results (i'm not to sure how good these are and maybe someone could advise me on some other methods to calculate an enclosure)

mh-audio.nl - Vented System


Next i started to draw all my parts in cad, this is so i could adjust anything if it needed to be to make sure it fitted together properly before i sent in onto my machine to be cut,


Below are all the pics of the cut 18mm mdf parts pre assembled and assembled. when i dampened the enclosure i used some 8mm foam underlay from carpet, now i used this because i got if for free and thought id give it a try, has anyone else tried this before and had good results?


a video of a test cut that i did to get the depth of the drivers mounting ring as it wasn't what was on the spec sheet is in the shared folder,

here is a shared google drive folder which contains images of build and video of test cut.

https://drive.google.com/open?id=0Bxklo0xJXZ8gN0V5SktobFpuVUk

please let me know if this folder now work?

any advise would be great, cheer Max.
 
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frugal-phile™
Joined 2001
Paid Member
18mm mdf parts

MDF is not all that good for making speakers… be nice to see the pictures (they are behind your Google logon).

I'd put these into a 2.5 litre box with a high-ratio vent tuned to 95 Hz. F10 ~70 Hz. About the same LF performace as FF85wk or Alpair 5.2 in the same size box.

Lower mids = 160-320 Hz, perhaps you have baffle step issues?

dave
 
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Hi Adason, sorry about that! I've shared a new link to a shared folder, hopefully you can all now view the pics and video.

MDF is not all that good for making speakers… be nice to see the pictures (they are behind your Google logon).

I'd put these into a 2.5 litre box with a high-ratio vent tuned to 95 Hz. F10 ~70 Hz. About the same LF performace as FF85wk or Alpair 5.2 in the same size box.

Lower mids = 160-320 Hz, perhaps you have baffle step issues?

dave

Hi Dave, again I've shared a new link, hopefully you'll be able to view pics now.

Yeah ok I had 18mm mdf spare but I would really like to make the cabinets out of birch plywood in the future when I have some more funds.

The enclosure is 2.47l so basically 2.5, fb is 87.74 and f-3 is 85.43 does that sound correct to you? F10~70? I'm not sure what is?

When you say baffle step do you mean the baffle inside the cabinet?

Regards,
Max.
 
frugal-phile™
Joined 2001
Paid Member
That seems close. As far as what we hear, F3 (the point where the response is down 3dB) is a meaningless measure. It is a leftover from the electrical filter theory used to model enclosures. F6 and F10 are much more useful.

The difference between F3 and F10 gives an idea of how fast the rolloff is.

dave
 
For a box as large as this, you have certainly braced the crap out of them. Note that centered on the panel being braced is not the best place.

dave

Haha i like your technical term ;). Where's a good place to brace and maybe I could get away with somthing a little thinner maybe 6mm? Are there any references around that I could read?
 
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frugal-phile™
Joined 2001
Paid Member
panel-resonance.gif


In the middle doesn't guard against this primary mode, but with such a small box, and thick build material, it is less of an issue.

One of the other things is that the holey braces tend to break up internal side-to-side standing waves, works better if the distance on either side of the brace is different.

dave
 
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