The best DIY speaker in the world?

[kye]

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.

Edited March 10, 2012 by kye
updated crossover diagram

[monaro8]

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

[Guest Muon]

Looking forward to the pics, Kye

[PorkBun69s]

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 December 11, 2011 by katattack74

[ehtcom]

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.

[THOMO]

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.

[Full Range]

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

[LogicprObe]

Good on you, Kye.

[JA]

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

[Mick35]

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.

[Mick35]

Also, out of intrest with this project, a similar, if not identical driver can be found at Jaycar.

http://www.jaycar.com.au/productView.asp?ID=CE2325&form=CAT2&SUBCATID=1020#4

[sir sanders zingmore]

Very interesting post.

How hard would it be for someone with absolutely no experience to have a go at building?

[Mick35]

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

[ehtcom]

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

Straight Eight.

Eight is Enough.

[Mick35]

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!

[Monkeyboi]

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.

Cheers,

Alan R.

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

[kye]

I must admit, i'm really happy to see such interest in this project - these speakers are too good (and cheap and easy to make!) to not share

here are some pics

[ATTACH=CONFIG]38959[/ATTACH][ATTACH=CONFIG]38960[/ATTACH][ATTACH=CONFIG]38961[/ATTACH][ATTACH=CONFIG]38962[/ATTACH][ATTACH=CONFIG]38963[/ATTACH]

monaro8 - this is a logical question, however my point is that actually these are the better drivers.. let me give you a bit more of a baseline. these drivers are better than all vifa drivers i've heard, all polypropylene drivers i've heard (although that's not hard), better than the focal 8" paper drivers I have (which retailed at $200+ea when they were available) and accuton ceramic mids. and for musical enjoyment they are in the same league as the scanspeak revelator series mids, the avantgard duo horn speakers, and quad ESLs. however, if you're talking about better quality fullrange drivers, then yes, i'm all ears about that too, however at this price, we can buy 8 for less than a pair of almost everything else, and having 4 per side will likely give advantages of slam and power handling that a single pair of better fullrange drivers will still likely struggle with.

katattack74 - i'd encourage a build by others.. not only to get a second opinion, but also to share some of the goodness around

earle - would be interesting to do a comparison between these and the fostex.. I suspect the fostex would win outright, but in value for money i'd say these are almost impossible to beat. have you heard the horn tweeters? i'd shy away from them - horns are fundamentally prone to resonances, and for the money they charge for these things you can get really nice ribbons!

thomo - yes, it's a fairly logical approach, and one I wish i'd explored 10 years ago.. would have saved myself a whole lot of money, but then again, i've had a lot of fun too i'm glad i've gotten here in the end though!

I find the magic of these things is really fragile - try to put anything on the ones running fullrange and the magic exits stage left instantly. that's why i've had to use the extra drivers to flatten things out. on more harsh recordings their normal response is odd at lower volumes and rip-your-ears-off-your-head at higher volumes, so they really need something to even them out. also, I suspect that the depth of the cabinet really helps too, which is something i've never tried before. the cabinets were designed as subwoofers and the panels sitting waiting assemly in the garage, so that's why they're the dimensions they are - I figured that if it didn't work i'd only have to cut two more replacement panels and then i'd have sub cabinets again. that's also why the screws don't match!

interesting point about the whizzer removal.. something to think about - if we can get away with removing the inductor I think that would be a win, although we'd be changing the cone mass too, which i'm not so sure is a good idea.

fullrange - would be interested in your impressions, I can see by your username you're ahead of the game on this kind of thing

in terms of an alternative to a supertweeter, you can build them without and see how you go - there is lots of high frequency energy up there, and I didn't miss it during a week of heavy listening.

JA - yes, my thoughts initially ran straight to "will more of these things be better? - line arrays!" but I think it will depend on your amp and room.. I ran these things seriously loud last night and they remained completely composed (room shook with the low stuff, the upper bass and lower mids were all physical like a good PA, medium yelling volume was completely undetectable) they had the 'bounce' that you feel when you're at a gig and the band and crowd are going off, absolutely fantastic. from this I think that they're able to produce enough volume for any listening in a small room, and sensible listening in a larger room. if you had a huge room and are an AC/DC fan then maybe more would be better, but i'd start with this the other aspect is that if you double the driver count then you'll halve the impedance, which makes it less SET amp friendly, and I think this is part of what makes the magic of the speaker. for me it seems to ignore most of the tradeoffs - it plays loud, goes relatively low, is efficient, is an easy load, and it's cheap!

mick35 - listening to them straight (especially in a non OB cabinet) is pretty underwhelming.. they're not flat enough as a single driver to really be palatable unfortunately. they'll also ruthlessly expose what the first watt of your amplifier sounds like, which in many (most?) solid state amps isn't likely to be that pretty.. the design can be scaled to use 4 drivers total (ie, half what I used) or doubled to use 16 total if you're willing to accept a 4 ohm load. if you're a bit wary then you could build a single speaker in the half version and see how it sounds. I found that even one channel is pretty nice - lots of depth and information.

that jaycar one might be the same driver - as usual jaycar copies altronics and jacks up the price!

whatmore - this is about as simple a DIY project as you can get - i'd enourage you to give it a go! you'd need to be able to build a box (or get someone to do it for you) - the hardest part of this would be cutting the round holes for the drivers. the electrical connections only require one part to be connected except the drivers and if you're careful you can get away with twisting wires together (or use aligator clip leads) and it would work ok. ideally you'd solder the wires together.

i'll put together some instructions with box and electrical details and upload them when they're done..

and Lo, the Straight Eight was BORN!!!!

[monaro8]

Speaker Model: Kye STR8"s

[monaro8]

Straight Eight.

Eight is Enough.

Speaker Model: Kye STR8's

[kye]

Here's some "design sheets" (scribbles mostly)..

http://www.kyelight.net/ebaypics/straight%20eight%201.jpg

http://www.kyelight.net/ebaypics/straight%20eight%202.jpg

EDIT: these crossover designs are early prototypes and are not balanced. there are more balanced configurations that have a reduced impedance (but are still valve friendly) for much better tonal balance. I will update the original post with updates as they are developed.

Edited March 10, 2012 by kye
troubles with pics

[monaro8]

kye

how about the next model up from Altronics???

http://www.altronics.com.au/index.asp?area=item&id=C2002

Any good @ 30w

Vanch

Oops! Typical hi fi nut question...already trying to make improvements!!!????

Edited December 11, 2011 by monaro8

[Steve M]

Wow! What a breath of fresh air this thread is, thanks for sharing Kye.

I'm going to try it out early in the new year ...

My only concern at this stage is about the bass. Is it really as good as you are saying, shaking the room? It seems like a difficult trick to pull off considering the TS parameters and the limited excursion for these type of drivers - and with an open back, no less.

Though, coming from you Kye it must be pretty special as you have had a lot of experience with quite a few spkr projects using different conventional drivers, as mentioned.

Anyway, I'm really looking forward to building and hearing a pair.

Regards,

Steve.

Edited December 11, 2011 by Steve M

[PorkBun69s]

kye

how about the next model up from Altronics???

http://www.altronics.com.au/index.asp?area=item&id=C2002

Any good @ 30w

Vanch

Oops! Typical hi fi nut question...already trying to make improvements!!!????

I like your style Vanch. ENaBL patterns and phase plug mods come to my mind already. Drivers x 8 = $120, MDF 2 sheets - $100 est, glue & screws = $10, Tools = borrowed, Sound? ...PRICELESS

[monaro8]

We can't help ourselves Mario...can we???

"Hey, these speakers/this amp/this CD player/turntable sounds AMAZING...now lets see how I can make the bugger sound even better!!!"

Ha! Ha!

We all do it I guess...better cables/interconnects/valves/stylus/feet/mat/tweaks/room treatments/new wife...oops (delete)/good cleaning of the ears/psychological adjustment etc etc....

Edited December 11, 2011 by monaro8

[kye]

hi monaro - no idea on that driver, but i'm immediately suspicious as power handling is something that tends to go with the 'bigger is better' mentality that has produced most of the dross that is in "hifi" shops.

of course, I could be wrong and judging a book by it's spec sheet is sometimes a mistake!

the only way is to build a pair of each and compare

steve, the bass is an interesting one - it's not normal bass. yes it shakes the room if you wind it up a little, and to my ears it is balanced with the rest of the spectrum, but it's very different to ported cabinets.

basically, it sounds empty. the speaker sounds like there's no bass until you get something with low frequency energy in it, and then it just renders that instrument.

if i'm honest the lowest part of it's response isn't the best i've ever heard (it's a little boomy) but it's there and it's mostly integrated and it comes for free with the drivers, and it's not objectionable. a friend and I have been on similar journeys over the last few weeks (he's just made the jump to some coral fullrange drivers) and previously he was using a high-end 3-way active system. his comments were that whilst the frequency extremes aren't the best ever, if the price of integrating them with other drivers is to lose some of the magic in the sound then it's not worth it. the weaknesses are easily tolerable because they give so much more information than normal speakers. he was saying that even in his active system the crossovers kill the magic of the drivers (and his are high-end valve crossovers) so I think that the less playing we do with these things the better.