NIBs

[daveh]

I managed to buy 8 ND105-8 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-214)s when they were mistakenly on sale for $12 a piece. I had them sitting around and wanted to do something with them. I had seen Chris Roemer's Nano Neo's using the 4 Ohm version which got very good reviews, and hoped I could coax similar results from using 2 of the 8 Ohm version in an MTM.

To keep the project inexpensive and keep with the Neo idea I chose the ND20FA (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-030) tweeter. I also wanted to keep the enclosure relatively small so that they would fit the bill as Christmas presents for my step-son and his wife as bookshelf or computer speakers.

I went with a vented enclosure with inside dimensions of 5.25" W x 13.25" H x 10.25" D. This gives an internal volume of 11.6l. I used a 1 5/8"x 4 7/8" port (http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=260-474). This gave an F3 of ~72Hz and an F10 of ~38Hz.

The enclosure was built with 5/8" baltic birch and the drivers were flush mounted. I used a couple coats of tung oil finish.


http://i635.photobucket.com/albums/uu80/dhancoc/final.jpg
http://i635.photobucket.com/albums/uu80/dhancoc/PICT4022.jpg

[daveh]

I will mention that these sound awesome. I first listened to them about 3 feet from the wall and about 3 feet apart as a computer speaker. They have a good amount of bass for music purposes. They did not seem forward to me and really had a laid back midrange. The tweeter added just the right amount of high end without sounding harsh.

When I placed them closer to the wall and a little farther apart, I had to turn the treble up a bit to make up for the increased bass.

DaveH

[Steve Henry]

Very nice! I love Baltic Birch with a clear finish.

[joeybutts]

These look great!

How does response and enclosure size change if these were to be run sealed?

Also, you said you flush mounted the drivers. Are you saying you mounted the drivers to the front of the baffle or that you actually routed out a recess for the drivers?

Thanks!

[daveh]

These look great!

How does response and enclosure size change if these were to be run sealed?

Also, you said you flush mounted the drivers. Are you saying you mounted the drivers to the front of the baffle or that you actually routed out a recess for the drivers?

Thanks!

Joey,

I made a mistake in the write-up saying they were flush mounted. I had thought of doing many different mountings, like rear mounting, etc., but ended up just surface mounting them. I definitely do not have the patience to route the recess for the ND105s.

The enclosures are actually undersized for vented enclosures. They could have really performed better in double the enclosure size up to 1 cu. ft. However my goal was computer or bookshelf speakers and so I went with a smaller enclosure at the expense of bass.

If you went with a similar size sealed enclosure you would be looking at an F3 of around 94 Hz and F6 ~72 Hz and F10 ~54 Hz. You would definitely need a sub to handle the bass duties in this case.

DaveH

[Mark65]

Black Sabbath fan?;)


Nice work, love the birch!:cool:


Mark

[daveh]

I am a Sabbath fan and NIB is a great song, but I did not think of that when I chose the name. I chose NIB as a acronym for Neodymium, Iron, Boron. Since all the drivers have neodymium magnets.

DaveH

[herb]

Very Nice. Clean looking build.

[JimHRB]

Similar design to Chris Roemer's Nano Neo "ntn" design. His use two ND105-4s in series with a ND20-6 tweeter. Box is a little larger and it models with a much lower F3. From the curve above, looks more like the lowend rolloff for this design is in the 40s not the 70s.

[Chris Roemer]

Similar design to Chris Roemer's Nano Neo "ntn" design. His use two ND105-4s in series with a ND20-6 tweeter. Box is a little larger and it models with a much lower F3. From the curve above, looks more like the lowend rolloff for this design is in the 40s not the 70s.

Yes, oddly enough, using PE's 105-8 specs (I have NOT measured THAT dirver) I can get a box response that looks very similar to that curve if I use a single woofer in 0.41 cf. with that vent, which gives an Fb in the high 40's.

Chris

[daveh]

Chris,

There were a few measurements posted here (http://techtalk.parts-express.com/showthread.php?t=220281&highlight=nd105-8). The measurements are different to PEs posted.

DaveH

[arlis_1957@yahoo.com]

nice looking build.
just curious, did you try reverse polarity and/or a higher order to align the phase of these drivers?

[daveh]

nice looking build.
just curious, did you try reverse polarity and/or a higher order to align the phase of these drivers?

I did try higher order, but did not get much better results for the price of more components. Tried to stay relatively inexpensive. Here is what the reverse polarity looks like. Looks like the phase is pretty well aligned.

http://i635.photobucket.com/albums/uu80/dhancoc/NIBsreversepolarity.jpg

Thanks,
DaveH