New $30/pair computer speakers

Mazeroth

Just completed my pair of open baffle, Hi-Vi B3N computer speakers and they sound absolutely terrific! After reading a large writeup about this stellar driver I decided to make my own pair of speakers utilizing this driver, and in an open baffle arrangement due to the high Qts and openess an open baffle presents. I'm crossing them over at 150hz to a subwoofer and they are blending seemlessly. They image like mad and sound much larger than a 3".

Check out this page for John Krutke's review of this driver:

http://home.new.rr.com/zaph/audio/audio-speaker18.html

Also be sure to check out the rest of his site. This man knows his stuff and documents things very well.

phoneisbusy

Nice! Did you use the filters from John's site or did you come up with your own? What's the dimensions of it ?

regards

Dave

jarros

Looks good! I've been wanting to start building some speakers of my own, and this looks simple enough to get me started. How did you decide what size of a baffle to use? Also, what are you using for an amp and crossover?

jcaut

I just bought a pair of the B3N's from John Krutke for $12---- The ones he tested, but didn't use, in favor of the square-frame version---- so a similar project is on my list of things to do. My first experience with Hi-Vi. So far, I'm impressed with the build quality and the fact that the measured specs actually agree with those published by Hi-Vi. Neither is very common with drivers as inexpensive as these.

Jason

gatemplin

They look great.

Hi Vi makes some great drivers, and very affordable. I'm trying to find an excuse for why I need these.

VR3

those look VERY clean, awesome job...

But I still got ya beat for the cheapest DIY project possible for compu spooks...

hehe..

Mine come RIGHT IN at about 8 bucks...

Awesome job man...those drivers arnt to much either, are those the blow outs?

Mazeroth

Put a few more hours on these little buggers and they just sound wonderful. I invited my brother over to demonstrate how well they imaged and had him close his eyes. I put on a little Norah Jones and told him to point to the instruments as he heard them. He was smiling and laughing his **** off! He now has a new appreciation for near-field music listening.

Answers to your questions:

Size: 7w by 14h. I chose this size because any taller and I think they'd look ridiculous as I was trying to get them as close to ear height as I could, and keep them asthetically pleasing. The baffle width was decided upon, again, by as wide as I could make them and keep them looking nice. Making open baffles helps with baffle step compensation and really fills in the mids and bass nicely without the need for a BSC like John Krutke uses. They are mounted four different measurements away from the edges, to minimize baffle diffraction. 2", 1.5", 1", and a long ways from the bottom! I really didn't put much planning into these speakers as I was curious how an OB computer speaker would sound and I'm quite floored with how they turned out!

I'm crossing them over at 150hz(ish) with a 125 uF capacitor on each, and using a little bit of EQ on my computer to tame the 8khz. peak and bumping up the highs at 12khz. a few db as well. It's barely audible, but it does help a little. For an amp I'm using the wonderful little T-Amp that can be purchases for $29 from Parts Express, other online retailers, and if I'm not mistaken, I think Target still carries them! They've been praised by many and have a huge following. Do a search for them on the net and check them out. They can run for hours and hours off 8 AA batteries or you can use a wall wart. I'm using a 13.5v 1.7amp one that Parts Express sells and it made even my now sold LSi7s scream. Here's the link to them on Parts Express:

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=300-952

I'm also using a DCM 10 inch 100 watt sub set to ~150hz for the time being. I'll be building a small sub for them in a few weeks (I hope) and giving this sub to my brother or someone in need.

Here's another pic of them being tested. The Sonic Impact T-Amp is to the left of my keyboard. The speakers are set up next to my 21" monitor so you can get a feel for their size. I may fiddle with placement a little more as well.

Ok, I've typed enough! Goodnight guys!

jcaut

They're not buyouts, they're just cheap. About $10 ea. at PE. Madisound has them for a little less than that, I believe. Quite a bargain at that price, IMO.

Jason

RuSsMaN

Neat. Now I have to buy a pair and see how they sound.

Cheers,
Russ

Toxis

interesting... might be worth the bucks to make for my computer. <$60 with an amp and all? I could justify that. Still leaning towards the klipsch promedia 2.1's which can be had around $100. What kind of wood did you use?

pjdami

Cool looking project Maz. The first thing those reminded me of was some mini Klipsch speakers.

Mazeroth

A little extra tidbit. The Hi-Vi drivers are the same drivers they use in Swan speakers. They manufacture their own drivers, use them in their Swan lines and sell them to the DiY market under the name of Hi-Vi. Check it out:

http://www.swanspeaker.com/drivers/index.asp

As far as the wood, I used some left over 3/4" birch ply for the baffle and 3/4" MDF for the base. I would have used a roundover on the front baffle but wasn't sure I wanted to see the layers of ply from the front. I used Olympic oil stain Red Oak and put on 5 coats of Olympic gloss poly, sanding between coats. I used Duplicolor truck bedliner spray they sell at auto parts stores and Wal-Mart for $6-$7 per can. I put on 3 coats of cheap black spray paint first because MDF loves to soak paint up, and it lets me get away with a better bedliner finish since I can now spray from 18-24in away and not need 10 coats to cover it.

For the money, the $100 2.1 Klipsch is probably the cheaper route to go, but I gaurantee these little buggers sound much fuller and detailed. You can make them to match your current decor and make them look however you want. For a small sub that will stomp the Klipsch just pick up a 25w plate amp from Parts Express and the Dayton 8" DVC, which is 89db sensitive. That will give you plenty of output and only cost ~$55 in parts, plus the wood. Or spend another $18 and grab the 70w plate amp. For roughly $120 you'll have a 2.1 system that you built yourself and will sound much, much better than the Klipsch.


http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=300-782

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-480

Toxis

I like the way you think... looks like I have a summer project now. :cool:

jarros

Originally posted by Mazeroth
For the money, the $100 2.1 Klipsch is probably the cheaper route to go, but I gaurantee these little buggers sound much fuller and detailed. You can make them to match your current decor and make them look however you want. For a small sub that will stomp the Klipsch just pick up a 25w plate amp from Parts Express and the Dayton 8" DVC, which is 89db sensitive. That will give you plenty of output and only cost ~$55 in parts, plus the wood. Or spend another $18 and grab the 70w plate amp. For roughly $120 you'll have a 2.1 system that you built yourself and will sound much, much better than the Klipsch.

Exactly what I was thinking for a sub! Thanks for the details on this project Maz. I too will have a summer project

Quick question regarding the capacitor in the crossover: did you only use the 125 uF capacitor, or did you use the resistors and inductors that "Zaph" used as described on his site?

Thanks again for sharing this info with us!


Jared

Mazeroth

I am only using the 125uF capacitor in order to cut the low frequency out. Anything under 150hz is really a lot for a 3" driver, especially in an open baffle alignment. This gives them a 1st order crossover at 150hz, which equates to -3db at 150hz, -9 db at 75hz, -15db at 37.5hz and so on. I tried them for a while, when I let them break in with a full-range signal, with no capacitor and they took the beating just fine, even at high volumes. Cutting the bass out helps with the high-end a little and also allows them to integrate with a sub easier. I took the caps off with the sub running, and since they put out so little volume below 150hz, you could barely tell.

I built these open baffles to test these little gems out but found out I really like the sound and don't feel they "need" the notch filter that John uses. If you want to follow his plans and build bookshelf speakers out of these, you'd probably benefit by using his notch filter and one of the baffle step compensation circuits. I'd probably do that with my other two I have sitting here but I purchased the round frame ones before he had a chance to test them. Turns out the square framed version are a little nicer and he built his electronics around that version of the speaker.

Again, this design I used is nothing special so feel free to get creative and do whatever you want. Just be sure to use a router on the back side of the baffle with a chamfer or roundover bit to help the speaker breath. If you don't there's not going to be much room behind the driver for air flow and things will get ugly.

rnp614

that initial link doesnt work for me! Anyone else having linky issues? Also, whats the backside of your speakers look like?

Mazeroth

I think John must be moving his site or doing a major upgrade to it. I highly doubt he took it down because he has years of speaker building on that site and hundreds of people have built his designs, which he provides for free.

My fiancee took our digital camera to her clasroom but the back of the speaker is nothing special. All you can see is the back of the stained board which is unfinished and a magnet coming out

rnp614

ok, thats what i figured. Just wanted to make sure.

VR3

If the back side of the speaker would be an issue...

You could build a 'frame' that could wrap around the back and wrap it in cloth... (removable)