The best DIY speaker in the world?

[millsy]

Yes that's true. Kye's right though, and I'm just learning this myself, and that is these drivers are on a knife edge, too far either way and you lose the 'Magic', tweak and fiddle to get it right, however, and you can be rewarded, with some great sound.

Looks very cool, wish I had the space to muck around with some larger scale DIY projects myself!

[logarhythm]

Just another update from me. I managed to build a pair of 'H' frames for a pair of eminence Alpha 15a's. Building these was easy enough, and as I was building and thinking about the crossover, I decided to, just for fun, try a 1st order cross at 100hz. Originally I thought about 130, but with a steeper slope. I didn't have all the parts for a steep slope, but I had some parts for a 1st order, but for a 100hz cross, I was going to need some serious amounts of copper coil. Managed to get some large inductors from jcar, and with the bass frames built, it was time for a test on the cross. At 100hz a complete failure, far to much mid bass, and it was drowing out my nice smooth top end, that I was enjoying. Add more copper! LOL! 70hz this time, much better, but after a little listening, still not right. Lucky for me the third time 'Was a charm' and at 40hz first order in my room, all is good. All up about 27mh of inductance. Yep! about 3kg of copper on each speaker resides behind the bass units. With the extra bass, these speakers sound very very good indeed. I know I can tweak further, and I will, but I'm happy right about now. These speakers are just so easy to listen to. They are lightening fast, ribbon tweets work very well, domes may struggle. They are nimble and very detailed, but not shrill or piercing at all, very smooth. They play very loud and very clean. I was sitting there by myself, and I wound the wick right up Twice what I'd normally go, and just simply enjoyed track after track. It was then I heard a noise, got up and it was someone at the door. It wasn't until I tried to speak, that I realised just how loud and clean these things were playing. I didn't even notice. FANTASTIC STUFF!!

Sounds like you are having fun mick.

You could lift the crossover to 100-150hz and add a capacitor in parallel to increase roll-off for the alphas. Add a large high-pass cap to the fullrangers tocombine with the natural roll-off to get a better integration and less cancellation in the low end. I think it would be another improvement. Very hard to get these things right without measurements but seems like you are having a good time tinkering anyway.

[Mick35]

Sounds like you are having fun mick.

You could lift the crossover to 100-150hz and add a capacitor in parallel to increase roll-off for the alphas. Add a large high-pass cap to the fullrangers tocombine with the natural roll-off to get a better integration and less cancellation in the low end. I think it would be another improvement. Very hard to get these things right without measurements but seems like you are having a good time tinkering anyway.

Hi logarhythm,

Thanks for stopping by. Yes a second order cross on the bass will be my next move this weekend. After listening this week, it needs to move up, but probably to only about 80hz, then with a 12db slope, less higher energy will get into the bandpass. However, the full rangers do need a little lift in the bandpass, to my ears anyway. The trick will be where to cut it off, and how steep do I go? The 'H' frames will be good to about 200hz, so I have room to move. A high pass on the Full rangers, I'm not so sure about? Maybe? but I'll leave them alone at this stage, although if I go second order on the tweets, and lift the crossover point, then your suggestion will be worth more exploration. As more measurements? I'm certainly showing restraint, I have the gear, and I know it frustrates the 'Measurement Club' on SNA, but that's not what I set out to do. Listening is what I've set out to do,with this diy project, then once I'm totally happy (not sure when that will be? LOL!) I'll measure to confirm my listening. As long as the sound keeps improving to my ears, I'm happy doing it this way. If I get totally frustrated at some point, or I'm not moving forward then the lappy and Mic will come out of hiding LOL!

[THOMO]

I am still yet to build mine.

I have in mind to try a square box with the drivers clustered together .More like a guitar amp quad box.

I can't see the point in having treble/midrange output down near the ground.

The Bose 901s sound best mounted about 900mm high.

[logarhythm]

I am still yet to build mine.

I have in mind to try a square box with the drivers clustered together .More like a guitar amp quad box.

Fine if you don't mind a 3cm wide sweet spot

Edited March 23, 2012 by logarhythm

[logarhythm]

Thought I'd better post a pic of my efforts LOL!!

What are the empty yellow cabs for if you don't mind me asking? Another project in the works?

[Mick35]

What are the empty yellow cabs for if you don't mind me asking? Another project in the works?

Um! yes and no. I'm kinda baby sitting them for a fellow audio mate, who has taken a different direction in his audio journey. He is a total perfectionist, and his DIY audio efforts far surpass anything I've ever screwed together. Simply the best sounding DIY speakers I've ever heard. There is also a pair of 18 inch bass cabs to go along with the yellow MTM's which complete the speaker system. If he decides to sell, I'll buy, no question about it.

Details can be found here

http://www.jirihifi.com/

[kye]

hi all.. I don't know what happened - i've been monitoring the thread by hitting reload in the window, but it never showed updates.. odd!

mick - so happy to hear you're now getting good results. it really did trouble me to think i'd made people go build something (and put in all that effort) to then not get what I was enjoying!

your comments about being lightening fast, playing loud and super clean and the temptation to turn them up way past normal (and sensible) levels are all my experience too.. I have to be very careful with the volume knob!! if you haven't already, try Queen - especially "we will rock you" and "another one bites the dust" - they're a match made in heaven on these speakers. another standout track (for speed) is I Love Being Here With You by Diana Krall from the Live in Paris album - very fast if your electronics are up to it

I look forward to your impressions of second order on the bass - definitely the right way to go.

Don't invest too much into a passive high pass for the 8"s.. I say this because you're putting a (likely low quality) cap in the signal path with the entire passband of those drivers. Caps do horrible things, avoid them if you can. As you know, these drivers aren't afraid of power, so that's not a reason to do it. If you don't like the lower end output of them (which I would suggest is a weakness they have) then perhaps trim your box so the cabinet isn't so deep, that will mean OB cancellation kicks in at a higher frequency, and the cab gets smaller too as a bonus!

They're nice looking cabinets BTW

Millsy - the next model that i'm working on is only about 20cm deep (and could be made even more shallow), so perhaps that might suit your reduced space allowances. I'll update here as it progresses

THOMO - in my latest crossovers the drivers near the ground are low passed (ie, woofers) and the one second from the top rolls off in the mid-band, so you're not getting highs near the floor.

however, don't let that stop you doing experiments! I love DIY because you can do crazy things and see what happens. logarythm is right - imaging might be odd on them, but at this price point it's about having fun as well as getting good results

Mick - I remember reading about those speakers from jiri. he is indeed playing in the high end of normal hifi, spending the money but on the right things IIRC. I listen to speakers of that 'level' quite regularly and they're always a joy, even years after the novely has worn off

[Mick35]

Another update. Saturday I tried a second order LR on the entire speaker, this time using the RAAL. Crossover points 140 and 3000. Just had enough parts to do the cross on the one speaker, just to hear, before I commit. Lucky I did it this way, complete FAILURE!! IMHO. The RAAL whilst sounding very good, just cut through everything else. Even with a heavy Lpad up to 8db The FR drivers just lost all of their speed and magic slowed to a plod. Dark and muddy in the midrange. The RAAL's just way too fast for the FR's with this type of crossover. Time to get back to basics and try Kye's revised crossover. KISS looks like being the way to go with these drivers.

[Mick35]

righto - here's the current crossover:

the drivers are (from left to right): RAAL tweeter, top 8", second top 8", remaining two 8" drivers

mick, perhaps this will round your sound out a bit?

whatever you do, don't put in a notch filter - I have gone down this road and you erase the magic from these drivers, leaving you with their other (less than stellar) attributes. these drivers are great because they have the magic, not because they're great drivers in any traditional sense.

Just looking at the schematic Kye, and that's a 2 ohm load. Am I correct? That might be a struggle for my amp?

[kye]

hi mick,

it's a 3.2 ohm load, and it doesn't dip beneath that anywhere in the frequency spectrum, and is higher than that in several places, so that's actually a lot nicer a load than many "4 ohm nominal" speakers. plus it's very efficient, so the amp doesn't need to put out much juice.

i'm running this on a 9W SET amp (300B output valve) from an 8-ohm tap and it's fine up until silly volumes. your addition of the woofers will lower the impedance if you're running them off the same amp, so that might be a factor for you, but give it a try and see? just be careful and start listening quietly and gradually turn it up - if the amp starts to struggle then you'd be able to hear it.

try it without your woofers first. I find this design doesn't lack bass. I run a sub with it to get extension, not output - my sub has a very steep rolloff (64dB/octave) at ~35Hz, so things like the lowest note on a bass guitar are too high for my sub, and are covered off completely by the mains.

Edited March 25, 2012 by kye

[Mick35]

OK I've swapped everthing back. I was a bit concerned about Kye's latest config with regards to the cross. So I've stayed with filtering the 4 drivers. To this I've lifted the inductance to 1.82mH and reduce the cap on the tweet, which is now a RAAL 150-14D to 3.3uf. The Bass has got a second order LR filter at 140hz. I'll stay with this for a while,only fiddling with the values. The RAAL is the best change thus far, an outstanding tweeter, and now that most of the 'Magic' is back with the FR's, the RAAL blends beautifully, giving top end detail, like no other tweet I've heard, just so smooth and extended, a pleasure to listen to. With the increased inductance on the FR drivers, there's more 'Meat' in the mid range, vocals have more realism, and texture, the highs in the FR's don't drown this out any more, the RAAL takes care of that. Happy to get it back to this. Before with a second order on the whole speaker was just a huge backward step.

[Mick35]

Saturday's update. What did I do today? First off, I dropped the crossover point on the Alpha's to 80hz second order LR. A great improvement to the overall sound. It cuts in low enough to keep my bass at a good SPL, but blends much better with the full rangers, giving just enough bandpass gain with the 12db slope. Mid range has more texture, imaging is more precise, soundstage, more realistic and proportional, better overall tonal balance. That's it for the crossovers, everything else has remained the same. The other tweak involves the placement of some acoustic 'egg crate' foam, which I bought at Clark Rubber this morning. My Full range drivers are separated by full length braces, so cavity resonances and standing waves, muddied the sound somewhat, still enjoyable though. The foam has really really improved things, even more so than the low pass crossover. Just much more clarity, and inner detail, far better imaging, just more natural. Timbre has also gone up quite a few notches. Steel string? or Nylon? Martin or Taylor? Plastic tiped drumsticks or natural wood? Zildjian or Sabian Cymbals? That's the type of Timbre detail I'm getting, astonishing really. I honestly thought I'd need a heavily treated room to get this much information out of a speaker? It would appear not to be the case? can't wait till I actually do some room treatments, Oh!, and a source upgrade and amp upgrade, cables and interconnects, hope these things just keep developing? Very enjoyable build thus far, the usual ups and downs, the backwards steps, but moving forward once again. The next few weeks should be good? If not Great? More to come.

[millsy]

Any updates? Been keenly following

[kye]

none from me quite yet.. have almost got my next pair done, but have been thinking about a new design that's a little less 'mainstream'.

basically, you use 8 drivers in each speaker, but each speaker would have two drivers on each side (ie, two facing forwards, two facing left, two facing right, and two facing rear)... this would allow a nicer impedance load, and you would put the ones that are low pass flltered on the sides and rear. it would behave like an omni speaker so would be a bit different from the current design.

however the advantage would be it only needs to be about 20cm wide and deep and if you put the air gaps at the bottom then would be equivalent to a normal design that's about 1m deep (instead of the 60cm currently) so should have a bit more extension.

the drivers are cheap enough to just give it a go.

I have a friend who might have reliable access to a cnc machine and mdf offcuts, which if I design the baffle right, would mean the same cut x 8 and then I just have to make the top panel and they're ready to assemble!

[Guest atilsley]

Mye, others

Thinking of a line array for my new ht room. Close to going with the bill fitzmaurice sla's.

http://billfitzmaurice.net/SLA.html

However, the straight eight appeals.

Q. I want these mounted in-wall.

Thoughts on cabinet design....eg taller/slimmer with possible front port...!?

Andrew

[kye]

hi andrew!

in-wall is certainly possible.. I would suggest building a pair first to make sure you're not committing to something that doesn't appeal to you - the sound of these isn't a traditional style sound!

in terms of design, it could be quite compact as all that's needed is to make the path length between the drivers and the opening from the speaker to be relatively long (ie, 600mm or more) which isn't hard to achieve if you go vertically (ie, the sound from the rear of the drivers goes down a cabinet of some size and then exits into the room at floor level).

i'd suggest including a good tweeter in the design from day 1, and depending on your music tastes and tolerance for frequency response rolloffs you may also want to augment the low end with a subwoofer, so consider these in your plans. of course, the SLA looks like it's got a very high rolloff, much higher than the straight eight design, so that looks like a given from your options thus far.

also, if you're considering options, zalytron have some line array designs that look interesting

kye.

[Guest atilsley]

Thanks Kye

I'm running the massive horn sub for this application....but there might be a gap around 70-100Hz. (I could add, say, a 10-inch woofer to augment this lower range if needed.)

I've also considered the Visaton B200 8-inch full range driver...buy 5 of these for a smallish HT app.

When I had some Fostex 206E's...I temporaily had them hooked up to the HT rig...just two channel...but boy, did it make a big difference. With the drivers being so efficient and fast, movies take on a whole new dynamic...definately a must=have for me with any future speaker for HT use.

When you said for me to trial the Straight 8's to assess the sound...I knew exactly what you mean. I've been a fan of these types of drivers for ages. The Auio Nirvana range would also work...being a little mroe expensive than what you've used, but less than 206E's.

If I went ahead with it...I'd probably build two roof mounted speakers for the rear channel (as I cannot put the speakers in the rear wall....due to furniture placement hard against the wall). I would use two drivers per box for the rears....using your design to run one of the drivers with lower bass.

Any ideas of a cabinet port size for the design for the fronts/centre (with 4 drivers in each and tweeter)...? The centre channel would, unfortunately, be quite high, as we have a large Plasma sitting on a 600mm tall sideboard.

Edited May 14, 2012 by atilsley

[greenie512]

Okay, heres another player .... one box wired up next tomorrow - more details at

http://speakershed.a...ojects/line-8s/

[Guest atilsley]

^{OK, I'm bitten.}

^{I'm thinking of a change to the already good theme here.}

^{It was suggested earlier that the up-spec C2002 full range driver be used. I like this idea...and to retain the costs, I'll tweak the config so that I have 3 units for the front left and right channels, and two for the centre channel. Eight drivers in total x $29 = $233.}

^{The left and right channels will be flush mounted into the double gyprocked walls. I will need to work on the cavity/cabinet size, plus porting...so ideas greatly appreciated by the learned ones. This wall backs onto kitchen cupboards, so I might be able to salvage a little real estate here, subject to Mrs not knowing.}

^{For the centre channel, this is interesting. I'd prefer to flush wall mount this...but we have a tallish sideboard with a large stand-mount Plasma on top. So, mounting the speaker above the TV would make it approx 1400mm from the ground. From an audio perspective, I'd much prefer to have the speaker located below the screen...so I'd need to build a nice low cabinet for this. Not too difficult...but then, this pushes the TV up by 22-25cm or so. (The seating is quite low...eg x4 electric HT lounge chairs.)}

^{See rough drawing attached of the two options I face.}

^{For tweeter, I might as well save on courier costs and retain the Altronics supplier for the 60 watt, 93dB C3004 unit, priced at $46.}

^{Not yet thought of rears...but could use x2 drivers per cabinet and mount in the ceiling, angled back to the rear wall. (I cannot / will not mount on the back wall, as the room size/layout dictates the seating is pressed hard back.)}

^{I've not yet even bought an amp...so will start looking down the track. (Anyone selling a basic unit?) With the high efficiency drivers, I won't need a lot of grunt. Funny, I was just looking at Decware's new SET valve kits where you can run 3, 4 or 5 channels in one chassis operating with two power supplies. Single Ended Triode home theatre for watching Arnie and Batman....nice. Would make surround music concerts a treat.}

^{Sub duties handled by the massive Bill Fitzmaurice Tuba horn (low profile), with 300-watt BASH amp and SP Acoustics 12-inch driver. Does the job...though a bit worried about filling the 50-100Hz range as the sub is really only suited for 50/60 and below. Until I get my new HT amp, I really won't know, as I'm only using RCA's from the DVD player to the sub amp at present...hence getting full audio signals filtering through, despite the 40Hz-110Hz cross-over in the plate amp. Most likely, I'll add, say, a 10 or 12-inch woofer to each of the left and right channels, or build two small dedicated subs and place them discretely.}

^{Regards all...and very happy to get feedback/ideas.}

^Andrew

[Guest atilsley]

Here's a pic of the existing room layout.

[Guest atilsley]

Interesting tweeters to consider -

P-Audio elliptical wave guide horn with comp driver from Cannonsound, $39

Selenium 60x60 horn with driver, $45

Food for thought...

[kye]

hi andrew,

there are a number of factors about this design that have been chosen specifically that perhaps you're not aware of (this thread is getting kinda long now!).

1) the driver choice is deliberate, and I believe it's a trap to believe the more expensive and less efficient driver is somehow superiour. whilst I haven't heard it, I would suggest that it is likely to lack the magic of this driver. think about it - they have the same cone but different motor mechanisms. now think about how hard it is to make a good cone (not that hard) vs how hard it is to make a good motor - when you buy high-end drivers you're mostly paying for the design and quality of the motor. if I said that there were two drivers that had the same cone but one had different motors and one was more efficient, which would be more appealing? i'd go for the more efficient driver without hessitation - and being a horn fan, I know you're aware of what effect efficiency has on dynamics!

2) the box type is NOT a ported box, despite talk of designs that look like one. it is an open baffle, albeit a folded one.

3) the driver may have a resonant frequency of close to 100Hz, but the completed speaker goes well below 40Hz. there will be no gap between 70 and 100 Hz if you build it in the ways I have described. the setup I have (using the latest crossover I have documented in this thread) provides clean bass down to the frequencies used in drum-n-bass, and loses out to only the lowest electronic notes, just as pretty much every other speaker i've ever built - most speakers just do not go below 30Hz.

I am happy to give you advice on how to construct a trial pair of these if you are interested, but care needs to be taken to get the right results, as these are NOT normal drivers, and therefore this design is also not a normal speaker!

[kye]

hi greenie!

congrats on a fine looking off-cut speaker!

I would highly recommend the latest version of the crossover (i've detailed it in the first post in this thread). the original one wasn't normal and (understandably) wasn't well received by previous makers.

keep us informed as to how you go and first impressions!

kye.

[Guest atilsley]

Kye...I appreciate your post...thanks.

So...the q is now...how can I possibly replicate your design in-wall....? I have flexibility with height and width...but not depth.

Regards