Building a pair of sonotube subs on the cheap (n00b) have questions

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SpyStyle

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Joined 2004
geocities.com/spystyle
Hello from Maine :)

I have a small question about connectors, but I may as well get into a discussion about the speakers too LOL

I recently discovered the so called "sonotube subwoofers" and I was excited to give it a try :)

OK I am using 10" Radio Shack drivers LOL, but I had them in a car when I was a youth :)

I had a pair of radio shack trunk speakers from around 1997. They had been stored in the corner of my parent's leaky New England basement for about a decade.

Every inch of the particle board was covered in mold but the drivers were good. I tested them and they worked. So I disassembled the cabinets with a Dremel oscillating tool (one of my new toys). I used a "fitzall" blade to cut through the staples that held the cabinets together.

Then I scrubbed the moldy boards with bleach and they were as good as ... usable.

Inside the cabinets I discovered there was a 10" subwoofer and a little tweeter, with no crossovers at all !!!

Rather than reassembling the cabinets I started to modify them to become "sonotube subwoofers". I cut a shallow channel in the boards so the tube ends could lock in, and I used "liquid nails" adhesive to stick them together.

These are not going to be seen, per say, they will be inside arcade machines. I painted them specifically to be mold resistant. But I can dig the color orange LOL

Below are some pics of my adventure.

































(they are not yet finished)

My question is -

Since this is a "sealed" subwoofer, and I want as few holes as possible, can I simply run two machine screws through the particle board as positive and negative posts ? Like two screws and on the inside of the cabinet, the wires are soldered to them.

Then on the outside I can just solder the wires to the machine screws. (?) That seems like a connection that can be made air tight.

So yeah, can screws be used in place of the usual terminals ?

Thanks!
Craig
 
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E

epa

Member
Joined 2010
why not use the old connectors.
for the paper cone i would use some white wood glue diluted with water and apply with paint brush.
for the metal and surround you could use vasseline spray,just make sure you not spray it on the paper cone.
regards erik
 
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Conrad Hoffman

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Joined 2007
conradhoffman.com
I feel dirty just looking at this thread. In the past I've built speakers using brass screws for terminals. I'd get #10-32 or 1/4"-20 round head brass screws and put them in from the inside. The speaker wires got soldered to the head of the screw, sometimes with the wire in the slot. Takes a fair amount of heat to get a good joint. On the outside I'd use a brass flat washer, lockwasher and nut to hold the screw in the box. Then I'd use a brass wing nut and more washers to attach the external wires with big lugs. Very effective, but today the brass hardware might cost as much as commercial speaker connectors!
 
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SpyStyle

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Joined 2004
geocities.com/spystyle
Carshateme - Yes I put lot's of liquid nail inside the tubes :)

Conrad Hoffman - Thanks for the info :) Maybe I should just run wire through a hole then fill it with liquid nail ? I haven't studied speaker stuff in years, but if I recall lamp wire is good for that :)

As a side note, I didn't bother to prime these, and I really should have LOL. I always use primer and I didn't realize what a difference it makes. With primer I bet 2 coats of paint would be enough, without it looks like I'd need 10. But these aren't going to be seen anyway so it's not a big deal.

I also have a question about the driver - if this is a "sealed" enclosure, do I need to put silicone or a rubber washer or something around the edge of the driver to seal it to the wood ?

Cheers!
Craig
 
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SpyStyle

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Joined 2004
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OK, I did more work in the "sonotube subwoofers" :)

I trimmed the rectangular particle board into squares. I added studs so the stress is not on the glue, it's like a regular speaker. And I decided to use the regular speaker terminals but added "feet" to keep them off the ground.

Here are some pics :



























Now I wonder - how do you guys test your speakers ? I wonder how crappy these are in technical terms LOL

I'd also like to know about cheap crossovers. Can't I just add a capacitor in line or something like that ? Or should I spend $20 on a passive crossover from eBay ?

Cheers,
Craig
 
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sreten

R.I.P.
Joined 2003
SpyStyle said:
Now I wonder - how do you guys test your speakers ?
I wonder how crappy these are in technical terms LOL

I'd also like to know about cheap crossovers. Can't I just add a capacitor in line
or something like that ? Or should I spend $20 on a passive crossover from eBay ?

Cheers,
Craig
Click to expand...

Hi,

I remember them but not what they were for, bass and treble reinforcement
in a car or full range I can't remember. In the most basic form the piezo
tweeters don't need a crossover, and normal crossovers don't work well.
See the wiki here for piezo tweeters.

If the original worked well with those vents then it now won't, but if the
original was a serious boom box it may now work well, not sure for what
though.

Stood vertically you'll never get them to work with the tweeter full range.

What is the intended application ?

edit : inside arcade machines ? how ? driven with what ?

rgds, sreten.
 
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revboden

revboden

Member
Joined 2011
SpyStyle said:
OK, I did more work in the "sonotube subwoofers" :)
Now I wonder - how do you guys test your speakers ? I wonder how crappy these are in technical terms LOL

I'd also like to know about cheap crossovers. Can't I just add a capacitor in line or something like that ? Or should I spend $20 on a passive crossover from eBay ?

Cheers,
Craig
Click to expand...

In technical terms, you did almost everything wrong, so... it'll probably work out fine :p

All you need is a coil to lowpass those, I'd go old-school and make one. Or just hook them to a full range output on your shop radio and see what happens.

BTW, those are woofers not subwoofers.
 
S

SpyStyle

Member
Joined 2004
geocities.com/spystyle
revboden said:
In technical terms, you did almost everything wrong, so... it'll probably work out fine :p

All you need is a coil to lowpass those, I'd go old-school and make one. Or just hook them to a full range output on your shop radio and see what happens.

BTW, those are woofers not subwoofers.
Click to expand...

Oh yeah, a coil for the woofer and a capacitor for the tweeter! I remember now :)

Thanks for chiming in, and you say I did everything wrong ? Could you explain how I could do everything right - so my next one will be better ?

I'll make a 3rd one LOL

Cheers!
Craig

sreten said:
Hi,

I remember them but not what they were for, bass and treble reinforcement
in a car or full range I can't remember. In the most basic form the piezo
tweeters don't need a crossover, and normal crossovers don't work well.
See the wiki here for piezo tweeters.

If the original worked well with those vents then it now won't, but if the
original was a serious boom box it may now work well, not sure for what
though.

Stood vertically you'll never get them to work with the tweeter full range.

What is the intended application ?

edit : inside arcade machines ? how ? driven with what ?

rgds, sreten.
Click to expand...

Howdy :)

These used to be a 2-way ported speaker, see the specs here :

http://support.radioshack.com/support_auto/doc19/19364.htm

Now I have removed the tweeters and tried to make them into a "sontube woofer"

The application - it will be horizontally placed in the bottom of an arcade machine, firing towards the front. Then there will be mid range speakers in the middle, and I will put the tweeters in the top. Each will have a volume control so I can balance them out, then there will be a master volume control. For volume controls I will be using those $12 amps from eBay. To drive the woofer I'll use an old car amp (called PYRAMID PB-101). I guess I should get a 3 way passive crossover from eBay so the highs, mids, and lows, don't get mixed up ?

This is my plan, I have only build two woofers and ordered 1 car amp. So I can change the plan.

That is my plan for 1 of the woofers. The other woofer is a spare but I have an extra peizo electric tweeter in a small plastic horn I can pair it up with. Maybe I could add am amp and crossovers and put the completed speaker in the backseat of my car ?

A woofer in an arcade machine is more for explosion sounds than it is for music :)

Also, the passive crossover from eBay I was looking at is called "AUDIOPIPE CRX-303"

Have fun!
Craig
 
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revboden

revboden

Member
Joined 2011
What is the Vb of those enclosures? I'll model them for you.

edit: I was kidding about "everything wrong" although I would let that adhesive cure fully before putting the drivers in the boxes so the VOC that off-gasses dosen't corrode the VC's and melt the glue on the spiders.
 
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sreten

R.I.P.
Joined 2003
Hi,

According to the specs you posted going sealed is the best option.

What you want IMO is a 4 channel car amplifier with built in active c/o's.
You want two channels bridgeable for the bass, use the other two for
mid and treble. They do exist with sensible active c/o points, search.

rgds, sreten.
 
S

SpyStyle

Member
Joined 2004
geocities.com/spystyle
Thanks fellas :)

As for "Vb of the enclosures", I don't know what that means. But if you are looking for the volume here are the tubes' dimensions :

12" circle X 23" tall
12" circle X 24" tall

There are two woofer choices for your modeling. I forgot I have an extra pair I bought a while ago called "Advent AM-10". And as you know I currently have the Radio Shack woofers installed.

I didn't install any tweeters.

I am still learning all this audio stuff LOL, thanks for all the tips!

Cheers,
Craig
 
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Spuddy

Member
Joined 2010
I can't really say much on the technical side of things, but I have to chime in and say I love what you're doing with this build! So shamelessly jumping right in, screw it if things don't work- You're a man after my own heart :D (maybe its a New England thing??)

Anyways, rock on broseph, I hope this works well for you!
 
T

tb46

Member
Joined 2006
Hi SpyStyle,

From your pictures it looks like the tweeter in the old boxes is a piezo tweeter, and a lot of people use these without a crossover. An standard crossover will not be designed for the very high impedance of the tweeter, one solution is to parallel the tweeter with the nominal resistance for which the crossover is designed (at least a 10 W).

Regards,
 
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