Delsol- inexpensive full range bookshelf.

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Here's one I've been keeping under wraps, but it's time to share.

Use the Aura NS3-194-8E, on sale for $10.50 from Madisound.
http://www.madisound.com/cgi-bin/index.cgi?cart_id=1251650.9881&pid=1705
Ignore the fs, it does far better than the numbers indicate.
Especially in my box.

One half sheet of MDF (you might could squeeze it out of a quarter sheet, with no mistakes)
Some padding for the back wall ( felt or carpet pad)
2"dia PVC (you can play with the port size)
1/2"hardwood face, or use 1/2" MDF or birch ply if you have to, but it won't sound as good. Mine is maple.

I developed this for use with the t-amp, and have found it works very well with the higher powered amp6.
I present this as an experimental starting point, and welcome suggestions.

design goals were-
cheap,
simple,
audiophile sound,
no crossover, just a driver (mechanical mods only),
rock the party.

plans at -
http://www.flickr.com/photos/47642593@N00/295706737/

Just build 'em- I think you'll be glad you did.
Pekar
 

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question about the porting...

wondering if the pipe section can be replaced with a rectangular section of vent that runs up the inside of the back wall? You might even get away with just a slot in the bottom at the back edge. That way if you place a bottom on the cabinet you can stand mount the speaker and your vent still works. Is there a special interaction going on between the two vent sections in this design? As it stands the vent action will be modified depending on what kind of surface the speaker sits on (ie. smooth floor or carpeted). Comments? Regards Moray James.
 
I intended that these be set on a hard surface like a desktop or bookshelf, not the floor. It would be easy enough to incorporate a bottom for other uses.

You can do whatever you want with the vent, but
I already tried the slot idea, with inferior results. Vents along walls are generally a bad idea.

I plan to use some birdseye maple for the face, with a painted body.
 
system Q and subjective sound

Trying these same drivers in small sealed box, what volume and tuning freq are you using and are you happy with the sound? Ref my thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=90151. I still think a TL is the solution but haven’t gotten any feed back yet. And to james as long as you know then box tuning freq a rect port should be easy to calculate.
 
Slot vents tend to...

provide
a broader BW in terms of load as compared to round or square ducts.
Seemed simpler to construct with all rectangular vents and I can see no advantage to switching to a round tube duct (in keeping with the design goal of ease of build). You could stretch this into two ducts and have a mini Onken design. This would also provide some internal cabinet reinforcment. Regards Moray James.
 

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The attached pic. is similar to what I tried, and was unhappy with the result.

Your idea is interesting, reminds me of the Solo-103.

This box is really quite small, and with 3/4" walls needs no bracing, IMO.

Pekar
 

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good picture....

yes that is what I had thought as it keeps things very simple with now round holes to cut or pipe to buy. What ever the tunning of the pipe you are using it can be matched this way without much effort. Dave Dlugos (PLANET 10) has a design for a mini Onken for a Fostex Fe127e on his site. While the tunning is lower than would be for your design the size is close and retunning the vents could be done to suit your driver. Though given the rather high Fs I am not sure there is really a lot of point to it as a sealed bos of not a lot of volume should attain the similar results but it is a nice design. Regards Moray James.
 
I don't find round ports especially inconvenient. I've done it with a 2" holesaw by butting the pvc to the hole and gluing it in place.
I did use a router to cut the 2 3/8" hole for the enclosure in the picture.
It depends on which tools are at hand.


When tipped on its side bass performance suffers.

I would also like to point out that this driver was designed by Ben Tang, and that it has a neodymium magnet.

Pekar
 
Construction tips.*

1. Tune up your tablesaw. http://store.thesawshop.com/catalogue/docs/tune-up.pdf

2. Rip the bottom and backs first at 5"wide.

3. Crosscut them oversize, and label each. Check your parts for square. Square parts fit together much better!

4. Rip the sides at 8 1/4".

5. Crosscut the sides at 9" (you can use the rip fence here). Label them and draw lines on the inside face indicating where the back and bottom meet. Use a square and be precise. Check that these parts are square.

6. Rip the top and face slightly oversize at 6 3/4"

7. Locate and cut the port hole in the bottom. This is either 2" or about 2 3/8" dia.. Round over the bottom of the port with a router only if butting the PVC to the inside of a 2" dia hole (1/4" bit).

8. Draw on the inside of the back where the bottom meets it 1" up.
Test assemble one side, back and bottom. if happy with the dimensions, test clamp these three parts.
Once happy, I like to assemble this much and let it dry overnight, before adding the other side and top. This method is more time consuming, but avoids fasteners like nails, screws or splines.
The lines you drew act as glue lines now. Square assembly is crucial. Jorgenson bar clamps work best. I like to dry clamp a square scrap piece to the face and bottom to make sure that dries square. I'll try to upload a picture ofthis setup next time I build a set, which could be a while. It is a maze of clamps at this point!

9. Remove clamps, test fit the other side and top again. If happy, rip the top to final dimension and glue on the side/top. I leave the speaker on its side with a HEAVY weight on top to hold the side on, and clamp the speaker top.

10. When dry, test fit the face, cut the face to final dimensions, cut the holes. For the bottom slot port, I use a 1" bit to cut the curved sides, then cut across with a high quality jigsaw. Drill in a little from each side to reduce tearout. Round over the slot port.

11. Drill and install speaker wire. Seal with silicone. Use something lighter than lamp cord. Monster cables are not recommended at these power levels. Round the edges of and glue in the PVC port. Install carpet pad damping on inside of box.

12. Chamfer or round over the INSIDE of the speaker hole. Make sure to not remove material required by the speaker screws. Attach face. When dry, round over the right and left sides of the face with a router.

13. Insert tasty beverage.

14. Install speaker. Predrill holes slightly smaller dia than the screws.
I solder the wire to the speaker, leaving enough slack to remove it and set it on top of the speaker for tweaking. Solder connectors or tin ends of wire to connect to amp.

15. Test and tweak! Keep the screwdriver out of the cone!

16. Remove speaker and apply finish if required.




These are not the most efficient instructions, but are designed to ensure the greatest chance of success, especially since many won't be using professional grade equipment.
For quick prototyping, I use a finish nailer, and assemble in one shot, without clamps.

I love PL premium construction adhesive for speaker assembly. It is a no odor, polyurethane construction adhesive that comes in caulk tubes. It expands slightly, like Gorilla glue, but has a lot more body. I buy it at Menards, I don't know if it, or a similar product is available at your local home center or not.
Please let me know of any similar products you've found. So I can recommend them to others. Polyurethane is the key word here.


*I haven't tested these directions. There may be errors and omissions. Be safe! Please check down the thread for possible updates.

Pekar
 
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