| first project, b20's - Click HERE for Original Thread |
| krikus050 |
It took me long enough to finally get something. I would like you guys to know that your accomplishments allow me to start building with confidence. I went the cheap route with pioneer b20's with a goal of keeping the project at $100.
I am going to build some half chang enclosures and maybe crossover with a tweeter. I hooked them up to my main amp while in some cardboard boxes. I played some rap and some album leaf. To let you know album leaf is a band playing mainly instrumental ambient type music that could put anybody to sleep. They were played to get some comparisons to my radio shack mach 3 speakers. The first was to compare the bass with the 15 inch woofer and the other was to hear midrange and treble compared to the horns.
The mid's were slightly muffled and highs very light. When bracing the cardboard box the bass turned out to be impressive even though the box is about .8 cubic feet. The changs will take care of the bass and testing them with some really crappy free tweeters with a 1uF cap make me want to get helper tweeters. I'll wait to finalize that after i build the boxes.
In keeping cheap, i was going to buy 2 sheets of 3/4" mdf. Is there any decent plywood that you could recommend that would be enough and be around $50. What is a cheap tweeter i should get?
If anybody wants to make laying out their cuts on wood easier, you should look at this optimization program. download the free version. http://www.download.com/Sheet-Cutti...cdlPid=10285263 |
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| Nelson Pass |
Send me your address and I'll send you a pair of the tweeters
I was giving away for these at Burning Amp. |
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| GM |
| quote: | Originally posted by krikus050
Is there any decent plywood that you could recommend that would be enough and be around $50. |
None that I'm aware of, at least in the thickness required. If it's in the budget, seal the MDF inside and out with a decent sealer such as this to 'tighten' up its tone a bit: http://www.lowes.com/lowes/lkn?acti...1801&lpage=none
GM |
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| AdamThorne |
If you like cheap and don't care about ugly, I've heard Oriented Strandboard (OSB) can be acoustically acceptable and the stuff is super cheap.
Haven't tried it myself, though. |
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| krikus050 |
| quote: | Originally posted by Nelson Pass
Send me your address and I'll send you a pair of the tweeters
I was giving away for these at Burning Amp. |
I would love to send you my address but i am not able to since i have not made enough posts to email people. I am under moderation. Are these the tweeters you bought 200 of?
I figured as much. I will probably go mdf then. I looked into much detail about staining it and some people say it looks decent with certain products. I will post my results and if it was easy or not.
| quote: | Originally posted by AdamThorne
If you like cheap and don't care about ugly, I've heard Oriented Strandboard (OSB) can be acoustically acceptable and the stuff is super cheap.
Haven't tried it myself, though. |
I will look into this, thank you.
I figured if i buy 2 47"x97" sheets of mdf I will be able to make the half changs and the 3.0cu ft boxes. I will keep whichever i like best and give to other set to somebody. |
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| Nanook |
kirkus050:
here's a rant against MDF: don't do it! Almost anything else is better. If you suspect you may try something better in the same cabinet spend some $$$ on Baltic Birch.
as impoverished as some of us may be, the results will be substantially better. OSB or even "chip board" has to better too: better dampening and less of the carcinogen formaldehyde !
in a pinch even use some sonotube (cardboard tube for cement forming columns and footings..)
As a minimum, maybe getting your local Home Depot or lumber yard to cut the MDF may be OK, as they cut it on a large panel saw, in well ventilated areas. If MDF, as suggested earlier, seal both the insides and out with a good primer , and paint . Some loudspeaker makers even take it further and suggest that if an enclosure is veneered on the outside it should be veneered on the inside and finished in exactly the same way.
stew:) |
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| blumenco |
stranded board might just be what the doctor ordered. dont be too afraid to try weird wood with these. they will sound good anyways.
You are in for a real treat. the b20 is a total overperformer.
I personally had the most luck sonically (and the best looks) with the driver back mounted against the paper gasket on the front of the frame. (screwed in from the inside of the cabinet).
it will require a removable rear panel, but that should not muck up the sound too much.
Nelson: got a link to what those free tweeters were?
I personally went on the super cheap and got the piezos with a .68 cap straight up. that was decent enough for my purposes.
enjoy,
Clark |
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| Nelson Pass |
| quote: | Originally posted by krikus050
I would love to send you my address but i am not able to since i have not made enough posts to email people. I am under moderation. Are these the tweeters you bought 200 of? |
ANYBODY can find me. Try the passlabs home page.
I bought 2000. :cool:
| quote: | Originally posted by blumenco
Nelson: got a link to what those free tweeters were? |
Hi Clark, how many would you like? Do I have to send them all the
way to Japan? |
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| AdamThorne |
Become the target of boys, run the risk that a doorbell ring might summon you to a flaming bag of doody on your doorstep.
...
Become the target of audio geeks, the bag is full of tweeters.
OTOH maybe it's your wife that is the target...
"But honey I HAVE to build it, I've got all these tweeters...!"
"... If I ever get my hands on the Pass guy..."
:D |
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| mightym |
B-20 cabinet design
Mr. Pass did a TL (?) design, however I can't find it on his site now....
I wondered how much material it took to produce? Maybe that it's not on his site, but here somewhere.
On the subject of OSB for speaker cabinets, don't let it get wet!, seal it well! Someone built a BIB with these Pioneer B-20"s and the little push in PE tweeter, and was very satisfied, except his distaff half wouldn't let them in the house.
The builders are now using an OSB product that is for subflooring, it looks to be about an Inch thick, and is rated for at least 16" span. This might be worth experimenting with. A builder told me he gets it for ~$25/sh.
John |
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| mightym |
| Sunday Morning Brain Fade? |
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| Scottmoose |
| I know the feeling... |
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| mightym |
| Will this Sketchup help make up for it? |
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| mightym |
| looked good 'till I shrank it so I could post it, I'll get the hang of this computer stuff yet..... |
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| krikus050 |
I went to home improvement stores yesterday. The only cheap and readily available thing was mdf so I bought a couple 4'x8' sheets.
I was thinking about doing 45 degree cuts to each side to improve the look of it. I have enough tools to accomplish this but wanted to know your thoughts on the sturdiness of this. Will mdf hold up with 45 degree cuts with screws going through them?
If not, will painting them hide the different edges you would see? I assume this would work with some decent sanding. I did want to stain them and figure that you would be able to notice the edges with that. |
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| mightym |
Krikus050
I don't know about others, there always are several ways to skin the proverbial cat.
I would cut nice square 90's, and glue with either pu ( gorilla ) or something like Titebond. The glue joint will be stronger than the wood.
As to finish, sanding, filling with Bondo works well for MDF ( helps to hide those seams ).
Finish with a coat of primer and more sanding, then a glossy black, white, or any color you desire. I treat this stuff like an auto finish.
There are other ways to do it, I've heard of people staining this stuff too.....
Whatever you do, I would strongly recommend sealing this stuff inside and out to prevent moisture intrusion, and wear a respirator while cutting and sanding, the resins in MDF are not good for your lungs.
John |
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| GM |
If you do beveled corners I strongly recommend you use glue/screw blocks over ~80 % of the seam's length and screw into these, so that the bevels are just glued. Frankly, I wouldn't even use screws since it weakens the glue joint.
GM |
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| krikus050 |
| quote: | Originally posted by GM
Frankly, I wouldn't even use screws since it weakens the glue joint.
GM |
I was planning on screwing into the wood while the glue was still setting. Wouldn't that not have that problem? |
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| GM |
Screws weaken any joint compared to a properly bonded one. Engineered bonding agents of today are far stronger than the hide glues of yesteryear, so reducing bonding surface area to add a separate component that stresses the materials in 3D is going in the wrong direction.
Of course in a HIFI app it's mostly moot since hopefully they won't be subjected to the type of abuse a prosound/whatever piece of gear gets, so adding them isn't a big deal, just that they aren't necessary anymore for a strong joint.
GM |
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| mightym |
| The problem there is, you can buy a Gawdawful #%&*pot full of screws before you pay for ONE Bessey clamp. |
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| Scottmoose |
| Makes the clamp look like good value then. |
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| krikus050 |
| quote: | Originally posted by mightym
The problem there is, you can buy a Gawdawful #%&*pot full of screws before you pay for ONE Bessey clamp. |
Yeah my cheapness right now has to outweigh my good judgment of everyone's advice. So the screws will be my clamps.
I know it has been a while but I just started to cut up the wood. Summer classes are time consuming in college. I decided not to build the 3 ft^3 boxes though it is simple and will do in the future. Maybe give my sister a pair as a pretty good present. I am only going to build the half changs.
With the help of GM, I am using the rest of the wood for a 4 ft^3 TL sub box for my car. Hopefully if time permits i can finish cutting today or tomorrow and at least start some gluing this weekend. Thank You guys for all your advice. |
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| Nelson Pass |
People are under the impression that I'm giving away tweeters.
I am for the next 27 minutes, if you are in the U.S.
After that, you must go to Madisound or Ports Express. |
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| Godzilla |
| I have over 20 unused tweeters currently. I hope to get thru 3 or 4 pair over the next year or two. Right now all i want to do is add felt/fabric to the back of my BIB wings... and build a new sub... |
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| gychang |
| quote: | Originally posted by krikus050
Thank You guys for all your advice. |
what cabinet are u building?
gychang |
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| krikus050 |
| quote: | Originally posted by gychang
what cabinet are u building?
gychang |
I am building some half changs. |
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| gychang |
| quote: | Originally posted by krikus050
I am building some half changs. |
should sound sweet, pictures if possible.
gychang |
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| mightym |
| quote: | Originally posted by Godzilla
I have over 20 unused tweeters currently. I hope to get thru 3 or 4 pair over the next year or two. Right now all i want to do is add felt/fabric to the back of my BIB wings... and build a new sub... |
What kinda sub you gonna build, Zilla?
Tapped horn mebbe?
John |
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| krikus050 |
| quote: | Originally posted by gychang
should sound sweet, pictures if possible.
gychang |
Definitely will. I hope to get them done this weekend. Starting to look slim since I have a project due tomorrow night. But Sunday will be a good day. Matte black paint will come later. |
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| Godzilla |
| My sub plans are straightforward and a little boring but for an angled front baffle just for interest. 3 cubic foot box with a port and an ACI SV12 - old faithful needs a new box. I will use the sub with my 165k BIBs. I am still working on a new supertweeter idea too... but am still futzing with the cap and coil. The supertweter should work nicely with the B20. Thanks for asking. |
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| krikus050 |
| I have four cuts left all 13 inches wide but my table saw only can accurately do 12.125 inches since it is such a small one. My circular saw is battery powered and the battery just ran out haha. Once the battery is charged, I will finish up cutting. I guess i will get other things ready while i wait. |
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| krikus050 |
One speaker done. One to go. The speakers has maybe one hour on it so no results are valid. Also no stuffing has been added. Pretty decent bass and the treble is better than I thought. I will wait and see if i want to add a tweeter or maybe try a small amount of EQ. I will do some A/B switching between my other speakers to see if I am missing too much top end. The speaker has great excursion. There is the muffled midrange and honking that I've heard so much about. I think I will definitely want to use phase plugs. The benefits of fullrange are there though. I love the way vocals come through. The box is very ugly with glue all over it. I was less than careful since I decided to paint them. I countersunk all the screw holes so I can fill them in when time comes to paint them. Whatever my next project is I will definitely work with something other than mdf. Once I am done college and get some real money I will tackle a ceiling to floor line array. Also get/build some better electronics.
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| krikus050 |
| The b20 is number 8 on the top sellers list at parts express. |
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| badman |
| quote: |
[/B] |
A little historical content I take it? 8, 16, 64 bit processor Nintendo systems :) |
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| GM |
Shows how interested in gaming I am, I didn't realize any were gaming machines.
GM |
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| krikus050 |
| quote: | Originally posted by badman
A little historical content I take it? 8, 16, 64 bit processor Nintendo systems :) |
don't worry. I have the wii under the coffee table ;)
I never even play them anymore! I will find time to get back into it someday.
| quote: | Originally posted by GM
Shows how interested in gaming I am, I didn't realize any were gaming machines.
GM |
Hey don't worry (I know you aren't) you may have noticed the other historical content on the racks like the realistic sta-2600 and realistic 13 band eq.
Ok so I stuffed the box and all the mids and highs are deleted from the port of course. The bass is so much better now. It has been playing all day. Doing some switching between my other speakers and a little something is missing but I may not need a tweeter. I can't really get into anything else untill sunday since i have a test on thursday and a project due saturday night. Maybe i will hookup the tweeter and have it temporarily stuck to the box. I put some twisted polyfil behind the wizzer. genious. I am really happy with this. |
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| krikus050 |
Bass guitar I think is coming out the best. Some of my favorite bands are rage against the machine and red hot chili peppers so i will be in heaven. I figured that full range and rock weren't going to mix as well as they are. I am going to have to build my mom and my sister some speakers now.
Does more excursion/louder playing break them in faster. do they break in at all on low volumes? |
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| badman |
Very different userbases, in most instances, though I've noticed a shift within DIY to a younger userbase than has been traditional, we're getting more young fellers as the appeal of DIY hifi has been very well represented online which tends to drive youthful presence.
I have and enjoy a Wii, mostly the very simple Wii Fit and Wii Bowling. It's something that's easy to pick up, more active than watching television, and appropo for both myself AND my kids- that's a rare conjunction, and a valuable one, because most of the things my 5.55 and 1.875 year old blonde girls enjoy are far too cutesy for a big grouch like me.
Funny thing is, one of the things I miss on the Wii is a lack of a Toslink output, would love to integrate it fully into the HiFi :)
In any case, your speakers look to be coming together nicely, I'm sure you'll enjoy the B20 (though I'm rather surprised people like those tiny neo domes with it so much, such a large change in dispersion character, maybe rolled in at 10k it doesn't matter much, and below it helps flesh out things off-axis)
Enjoy mate! |
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| krikus050 |
| quote: | Originally posted by badman
Very different userbases, in most instances, though I've noticed a shift within DIY to a younger userbase than has been traditional, we're getting more young fellers as the appeal of DIY hifi has been very well represented online which tends to drive youthful presence.
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I have been in love with speakers since I was about 2 years old. My dad had some realistics mach IIs and realistic sta 2600. There is video of me bobbing my head to the music slightly off beat and becoming off balance from my big two year old head. It, as you can see, inspired my first setup up with an identical amp and the mach III's which I got because of the horn midrange. Plus my dad got me some free subs when I was about 16 and started in car audio since then. So after many more years of new information and once I stumbled upon this site I figured i was capable of doing something diy home. Nest step will finally buying some reference books and buy mjks sheets. Then I will be in business.
| quote: | Originally posted by badman
In any case, your speakers look to be coming together nicely, I'm sure you'll enjoy the B20 (though I'm rather surprised people like those tiny neo domes with it so much, such a large change in dispersion character, maybe rolled in at 10k it doesn't matter much, and below it helps flesh out things off-axis)
Enjoy mate! [/B] |
Yeah I will have to see if i want to actually add the tweeter. If i do it will definitely be front and center so to speak. Shove in right in front of the b20. |
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| GM |
| quote: | Originally posted by krikus050
Does more excursion/louder playing break them in faster. do they break in at all on low volumes? |
Yes. Not really, the starch (or whatever they use today) in a typical spider needs to be flexed out.
GM |
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| krikus050 |
| Makes sense since Loud is Beautiful. I heard that somewhere once :spin: |
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| GM |
But only if it's 'clean'. ;)
Yeah, if you're old enough to remember, it was Cerwin-Vega's marketing mantra from their '70s Sensurround cinema system. Frankly, I'm surprised they haven't commented about me using it since my well published preference is Altec.........
GM |
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| Special Ed |
| I saw "Midway" in sensurround. Quite an experience. Shook the whole damn theater. |
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| krikus050 |
I am not old enough to have experienced Sensurround but I have heard of it before. I am 23 to let you know.
This past Sunday i put together the other speaker and since then i have decided no tweeter is needed. On my receiver i did turn the bass up 1 notch, the mids down 3 and the highs up 3. I haven't a clue how much it alters in terms of dB or width. It sounds right to me though.
I even got my cat interested in audio since he has been listening with me.
Maybe it's just that he likes to sit on papers...
This Sunday i will try to get them painted. |
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| gychang |
| quote: | Originally posted by krikus050
I am 23 to let you know.
I have decided no tweeter is needed.
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You are just a tadpole among the bull frogs here...
I was shocked at improvement when I added a tweeter on my B20... to let u know.
gychang |
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