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kye

The best DIY speaker in the world?

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Hi All,

Since I made my first DIY speaker 16 years ago, there has been the occasional time that i've lost sleep over hifi, but the last 2 weeks may have been the most excited i've ever been about hifi.

You see, I have designed and built the best DIY speaker i've ever heard.

..and it's one of the best speakers I have ever heard, regardless of price.

..and it's efficient enough to work with low powered SET amps, even in large rooms.

..and it's very easy to drive, with an impedance curve that doesn't drop below 8 ohms.

..and in its basic form is one of the cheapest hifi speakers available.

..and it can be built with no experience, and minimal tools.

So, how on earth can this be possible?

Basically, as much as I would love to claim credit for being a good speaker designer / miracle worker, it's really down to a completely un-sung hero.... this driver from altronics - http://www.altronics.com.au/index.asp?area=item&id=C2000A

But wait, you say.. this can't possibly sound good! Look at the frequency response! Look at the power handling! There's no way i'd buy one of those!

Sadly, that's what many people have said, and that's the only mention of this driver I can find on the net.

In fact, I made all of these mistakes when I first designed a speaker using this driver about 10 years ago. It was only when I was cleaning out the shed that I gave them another listen, taking the notch filter off them, and was amazed as they suddenly came to life! Hearing things you've never heard on your favourite CDs before through a speaker that you've kept in the shed for a decade is a sobering experience!

OK, so how on earth can we overcome that response? and the low power handling? the simple answer, is that at just under $15 each, we start by buying 8 of them - 4 for each speaker.

we put the top two of them in series and run them fullrange.

we take the other two, connect them in series, but run these through a 0.05mH inductor. then connect these pairs in parallel to the amp.

this means that at high frequencies (where the frequency response is higher) only the top two are making sound. then when we go lower to the midrange, the other two kick in, and from there down it's all 4 drivers contributing.

this rounds out the sound, giving a nice balanced response.

also, in the highs the impedance is 16 ohms, and when the other two kick in it drops to 8 for the rest of the frequency range.

so, we've now got a balanced speaker that can take about 60W, and is about 96dB efficient, and a minimum impedance of 8 ohms. but they've got a 80Hz resonance frequency! how do we make bass?

this comes from the cabinet, and i'm not entirely sure why it works, but it does.

we start by arranging the drivers in a vertical line, making speakers about 90cm tall.

then we make the cabinet for them about 600mm deep, and we leave the back panel open, as this is an open baffle design.

i'm not entirely sure how an open baffle design with drivers that have a 80Hz resonance can give low bass, but it really does. these things go down to 40Hz and probably lower. I have to position mine a little away from the backwall as I get too much bass in my 4m x 3m listening room.

and that's it!

ok, you're right, that's not completely it...

i've added a super tweeter to help above about 15kHz, but it's not required. I happily listened to these for a week without hooking up a tweeter, even though i'd already mounted my RAAL ribbons in the baffle. and before you ask, yes, a $1000 pair of tweeters is a good match for the quality of these drivers - they're that good.

so, what's the downside? surely this design can't be perfect? you're right, it's not.

these drivers aren't for people who like measurements, they're for people who like music.

these are the downsides as far as I can tell:

they're not completely flat, and you can hear it.

they're not small - 600mm deep and 900mm tall is a tad bigger than your average bookshelf speakers.

they're not going to make you look rich and sophisticated if you're trying to appeal to shallow people who only care about how rich you are.

however, on the plus side, they're very transparent so you can also hear an incredible amount of information in the music, they're very fast and give an incredible amount of emotion in the music, and so you simply don't care that they're not flat, small, or impressive to snobs.

one more catch....

when I say they're very dynamic and very transparent, I mean it. these speakers will not flatter your system. if the first few watts of your system sucks, these speakers will expose it mercilessly - the more transparent something is, the less forgiving it is of poor quality equipment upstream.

I'm using these with a relatively high end 300B SET amp, which is ideal for giving great quality in the first few watts. a 200W amp will likely sound awful through these things, but I guess you never know until you try - different amp designs will give dramatically different results.

i'll post some pics and a crossover diagram soon.

...right after I finish clearing my old speakers (that include about $4000 worth of drivers) out of the way!

EDIT: here is the latest version of the crossover - if you're going to build these, go with this one.

09032012628.jpg

Edited by kye
updated crossover diagram

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Good morning kye,

this is a very interesting read.

So, my first though after reading all your comments is...if these cheap speakers sound that good...how would this system go with much better quality drivers????

Hmmm?

I wonder......:)

Cheers...Vanch

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Wow..good work Kye. Pics and build notes please :) I'm tempted to try out a DIY proj, yours seems economical enough to warrant a test build.

Edited by katattack74

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Thanks for the great write up of your new speakers Kye.

I too am looking forward to pics.

Good morning kye,

this is a very interesting read.

So, my first though after reading all your comments is...if these cheap speakers sound that good...how would this system go with much better quality drivers????

Hmmm?

I wonder......:)

Cheers...Vanch

I have always wondered what a pair of speakers running 4 Fostex FE206e and a horn tweeter in each cab would be like.

FR-FR-T-FR-FR.

Cheers, Earle.

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Kye,

Interesting post as usual.

I wish more people on Stereonet would pursue experiments like this.

I have been suggesting to people with Fostex drivers that the best way to get a better balanced sound would be to implement them in such a manner.

Simply removing the wizzer cones from the secondary drivers might work just as well.

Drivers do not need to be expensive to sound good.Indeed many modern drivers seem to suffer for being built to handle lots of power and bass.

Some of the wizzer coned guitar speakers can also sound very good.I had a pair of RCF 10 inch wizzer coned drivers that sounded much better than the Fostex I was using at the same time.Perhaps not the treble extension but better in other areas.

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Great wright up key

I always let my ears and senses to be the final judge

I would be willing to build a pair in fairly quick time, to compare if you put up some plans ect

Also is there an alternative to a super-tweeter should one be required

FR

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Hello Kye

Thanks for your sharing your project. It sounds great and I'd love to share a listen based on the enthusiasm I hear.

Given the price of the drivers one could do a sort of Pipedreams version.... 16 drivers a side in a tall column, with a high sensitivity tweeter in the middle to match the increased sensitivity. And a sub for kicks. I'd like to hear either.

Best

JA

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I've got a pair of these drivers kicking around. Bought them to try out on a OB project, but sadly I was underwhelmed. The way you have implemented these drivers though, has sparked my curiosity with these drivers once more, just need to get another 6, I certainly didn't think to do that originally (they are cheap enough). A great Xmas OB project beckons me. This is the SNA I like to see, thanks for sharing your ideas Kye, looking forward to the next istallment.

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We just need to put a name to this design discovery? And make it a 'Sticky'

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We just need to put a name to this design discovery? And make it a 'Sticky'

Straight Eight.

Eight is Enough.

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Straight Eight.

Eight is Enough.

Straight Eight, I like that. Always loved the sound of a straight Eight engine. Like this one. Note the name on the side LOL!

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Hi All,

Since I made my first DIY speaker 16 years ago, there has been the occasional time that i've lost sleep over hifi, but the last 2 weeks may have been the most excited i've ever been about hifi.

You see, I have designed and built the best DIY speaker i've ever heard.

<<<< Rest of this interesting post clipped only for brevity. >>>>>

Sounds like something well worthy of an audition. Keep us posted Kye. :hiccup

Cheers,

Alan R.

(Posted from the Qantas Club Lounge, Adelaide en-route to Brisbane)

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