DIY Speakers! Any other mad scientists here?

[Oktyabr]

I've been through enough speakers to stock a second hand boutique. They've always been the element that I've been most critical of... I guess I'm a "speaker guy" as opposed to someone who puts much attention on the upstream components. I've even owned some very cool single driver full range towers (Sachiko double mouth horns) for a short time but then just about two years ago I decided to build my own.

Anyone else?

 

[mlucitt]

I have built several special purpose speakers - horn loaded PA, subwoofer, electric bass "bottom" and others but I leave the Hi-Fi speaker design and construction to the corporates such as JBL, Infinity, Altec, Cerwin Vega, Acoustic Research, etc. I feel that there are too many compromises to be made in designing a full-range speaker system capable of enough SPL to fill a room and yet not be as big as a refrigerator. Lots of engineering is required to balance out all the variables and it just makes my head hurt. I do like experimenting with different passive speaker drivers and crossovers, but even that gets scary sometimes.

 

[laatsch55]

I built my K-Horns in a friends basement (my husband in law actually) with a 7" skillsaw , a straight edge and small protractor. Haven't regretted a day of that 3 month saga. That was in 1984.

 

[Oktyabr]

My first full range, single driver (highly modified 8" Fostex 206E) speakers that infected me with the DIY bug. Someone else built these:


(clickable thumbnails):






From an earlier post a quick mini review:

"One of the big trade offs in speakers of this design, well known to those that have an interest in them, is that their frequency response can vary relatively widely at different volume levels. I now know first hand what is meant by this. Every speaker I've owned, with the possible exception of my maggies, varied somewhat in how they sounded at different volumes, generally rolling off the extremes of the reproduced range as the volume falls. These are different and hard to predict exactly what they will sound like when different volume levels are used with each individual track. So far none of the combinations have sounded "bad"... just surprisingly unpredictable. Some seem to loose the bass first at low levels, some actually seem to exaggerate the treble at the same volume, others just seem to drop most of the mid range quite badly. Fortunately where they seem to sound best, at least in my room, is at a fairly loud but comfortable level. Not so loud you can't carry on a conversation but loud enough you can listen to the nuances in a piece of music even though someone else in the room prefers to talk"

" I find these are very revealing of the specific recording. Realistic vocals, as "in the room with you" were very hard to find. These come close but not quite in the majority of cases. That said they do reproduce good recordings with a very natural sound and live recordings especially sound "live" but I think I still prefer the Dahlquist DQ-20i or the Vandersteen 2C for vocals. Jack Johnson sounded fantastic, Diana Krall always a pleasure to listen to, Natalie Merchant sounded a bit more subdued and compressed, probably more revealing of the recordings mastering and production than her voice. I listened to some choir recordings too and these did not disappoint in the slightest! Wish I actually liked choral pieces"

 

[Oktyabr]

The first pair I ever built myself using Audio Nirvana 8" 'Super 8s' in simple tuned port cabinets made of 3/4" baltic birch. Based on plans supplied with the drivers. Very good results! Built mostly with skill saw and some wood glue.:

(clickable thumbnails):












These really took some time to break in sounding best after getting about 100 hours at medium volume through them. Originally powered with a tiny 15wpc@8ohm T-amp, later upgraded to a bigger 50wpc@4ohm T-amp (Dayton DTA-100):

"While these are probably only eating up two or three watts each I think the reserves provided by the bigger T-Amp is helping the bass unfold a little bit. Highs and mids are still there but things sound a bit more punchy with perhaps a half db better performance on the 60Hz and lower range.

I love the sound of the tiny Sonic Impact and if all these speakers do is improve in the 60Hz and lower range with this bigger amp, and time, I don't think I'd be able to ask for much more.

Steely Dan sounds fantastic on these speakers, I particularly like the "bark" of the keyboards... stringed instruments and any percussion is what single driver speakers excel at and these are no exception. Mandolin, acoustic guitar, violin are all superb. One Bela Fleck track, "Bug Tussle", from his work with Edgar Meyer on Music for Two has Bela's banjo playing Bach (?!?!) with a bow drawn upright cello accompaniment that made my jaw drop... These suckers HAVE bass, on the right track, the stuff you can feel in your ribcage. I don't even want to think what that track might sound like on speakers that might overemphasize the bass region.

David Sanborn's "Inside" has a track where Sting sings a cover of "Ain't No Sunshine" that I stumbled across... it's become one of my newest "reference tracks". You can hear Sting get comfortable on a stool in front of a microphone and then the very subtle snapping of his fingers as he sets the pace for the tune before breaking into one of the cleanest recordings of his voice I've ever heard. Excellent cover, superb recording... that these speakers simply eat up like ambrosia from heaven.

'm not sure I've ever owned... or heard... another pair of speakers that imaged like these do! Certainly they throw a beautiful center presentation, as if my VR-12 center was the star of the show (and it's not even in use!)... but it's the width and height that I hear that's outstanding. A good example is Pink Floyd's "On The Run" from the classic Dark Side of The Moon. I use this song specifically for this purpose, to see if the dispersion of one speaker can seamlessly blend with it's opposite as the heavy channel fade of flying saucers (or whatever that sound is supposed to be) moves from left to right and so on. Not only do these convey a solid transition in the center, as the sound moves from one to the other, but the sound actually seems to continue several feet PAST the speaker, at least the one that isn't so close to a corner anyway. This is a cool effect!

I've also noticed some instruments definitely have a vertical presentation in the right tracks, perhaps below the driver and often a few feet above it, but what really gives these a character of their own is that they don't do this sound staging with every track, with every instrument... certain ones jump all over the room, others stay quietly in center stage and so on.

I tried making some "bass tubes" out of cardboard, just as an experiment. The cabinet designer says that the 6" port, given a 6" long tube, will behave exactly like the same design with two smaller 3" ports instead, loosing a bit of the heat in the midbass but extending the deep end another 1/3 octave. I don't think the cardboard is the best solution and will probably break down and order the correct tubes from parts express ($6 for the pair) if I can figure out what else to have them throw in the box

I'm not sure if these speakers would be everyone's cup of tea but I find them quite addicting to listen to... And for the price (approximately US$300 + time and labor) I can't think of a speaker that I would rather spend that same money on; certainly no bookshelves I've heard and/or owned... and when you consider that unless you are talking about very exotic SET monoblocks or something, the fact that these can sound VERY good with an amp that costs a paltry $100 (or less) makes them a true bargain in my mind.

"

 

[Oktyabr]

Then I moved those same drivers to a different, much more difficult build, the "Metronome" ML-QQWTs. ML-QQWT? A "Mass Loaded Quadratic Quarter-Wave Tube" (say that five times fast!). Look kind of quaint, eh? Actually a computer designed build specifically for my Audio Nirvana drivers based on ML King's quarter wave Mathcad worksheets (other variations of this same speaker are available): http://www.frugal-horn.com/metronome.html





I played around with these forever, trying different stuffings, amount of stuffings, different port configurations (they are/can be ported at the bottom), etc. but never quite got them to the point where I wanted to stop trying new things...

A mini review from the old Sound Thinking forums:

"Compared to the original "2.8mkII" (earlier in this thread) these DO have a better developed bottom end, the goal I was after. It's still not ultra-deep and may never be there but certainly a significant improvement, really only showing it's roll off on certain tracks, electronica mostly, that I know have a palpable bass presence... a prime example is the bass riff that comes in at about 20 seconds in Crystal Method's "PhD": http://www.youtube.com/watch?v=2Za4CR8lFrw

These speakers will convey most of that song but the very bottom dip in that specific bass riff is notably more rolled off than the slightly higher section that precedes it. Not sure exactly where in the freq range that would be but I'm guessing under 40Hz anyway.

This metronome build also seems to have slightly decreased their efficiency, now requiring just slightly more on the big knob to produce the comfortable listening levels that I grew used to with the 2.8mkII.

Imaging is not really less or more but rather different, due I'm sure in no small part to the slight tilt of the drivers and the shape of my room. On one track (I don't remember which) my wife actually stood on a chair in the back corner of the room so she could put her ear next to one of our Klipsch SS1 surround speakers and thus verify that the full image we were hearing was coming *only* from the metronomes in front! It is spooky how good these can throw sound in our room with the right track. Conversely "toe in" is a much more finicky matter with these to get that same "center stage disappear into the room" effect that the smaller 2.8mkII bass reflex cabs produced so effortlessly. I really think in a larger room, with more space to spread them apart, placing these "metros" wouldn't be such a task either but in their default placement (as photographed) they take a good deal more fine tuning for the sound stage to fully materialize.

So there you are, flatter throughout the whole frequency range with a more extended lower end, but also needing more room, a bit more power, and careful placement to sound their best."

 

[orange]

First of all, I want to thank you for coming over here and I just saw your posts...I see that Wardsweb has joined TH and between the two of you I can tell I'm going to have a BALL learning about speakers! I have built a few speakers here and there but it's limited to reusing cabinets with mostly used drivers and stock crossovers. I have learned how to make good matches but I am an amateur...

I think a great percentage of members here may have moderate to extensive experience with speaker building and modification, which is somewhat astonishing. It's like Larry asked people he perceived to share his passions to join and it worked in spades!

Speaker people love amps in turn because veneer sucks without vibrating!

Leave it to somebody named after an amp maker to get it last...

 

[Oktyabr]

These are my latest babies... They recycle the AN Super 8" full rangers in open baffles and a pair of Goldwood 18" 1858 woofers in computer modeled "H" frames, also dipole. I run the signal through a miniDSP digital crossover that's been calibrated to the room with a Dayton calibration microphone and the excellent REW room EQ software through bi-quads on all four channels. Those feed out to my Dayton DTA-100 T-amp which powers the AN's on top and a Yamaha M-65 which feeds the big 18"s. 40 lbs of bricks also in the same 3/4" baltic birch ply as the rest of the cabs now sits between the top baffle and the H-Frames on the bottom, raising the top components up about another 3" and at the same time stabilizing the bottom components during very deep bass hits. Between the actual design and the room-tuned EQ'ing, also a part of the digital crossover, they provide an almost flat 20Hz-20KHz, truly a full range speaker.

(clickable thumbnails)

Here you can see the cut sheet I made to help conserve wood:


Here you can see the 18" woofers, the calibration microphone and the cabs shaping up:





Here you can see some detail of the open baffles and one shot of the concrete bricks in place before I fab'd some wooden wrapping for them:

 

[Oktyabr]

Here you can see a measurement before the full DSP with room correction was applied. The very squiggly one shows bi-quad programming suggested by the REW software after running several sweeps with the calibration microphone. I also pumped a little bass boost into the 18"s to help level them out. I never did take a screenshot of the resulting test, but yeah, it's pretty much flat



EDIT: Here is a link to the very detailed build thread, including some rather creative mockups I modelled (and a three way version using ribbon tweeters) on the archived ST forum: http://starchive.phxaudiotape.com/viewtopic.php?f=12&t=7653

 

[laatsch55]

My first full range, single driver (highly modified 8" Fostex 206E) speakers that infected me with the DIY bug. Someone else built these:


(clickable thumbnails):






From an earlier post a quick mini review:

"One of the big trade offs in speakers of this design, well known to those that have an interest in them, is that their frequency response can vary relatively widely at different volume levels. I now know first hand what is meant by this. Every speaker I've owned, with the possible exception of my maggies, varied somewhat in how they sounded at different volumes, generally rolling off the extremes of the reproduced range as the volume falls. These are different and hard to predict exactly what they will sound like when different volume levels are used with each individual track. So far none of the combinations have sounded "bad"... just surprisingly unpredictable. Some seem to loose the bass first at low levels, some actually seem to exaggerate the treble at the same volume, others just seem to drop most of the mid range quite badly. Fortunately where they seem to sound best, at least in my room, is at a fairly loud but comfortable level. Not so loud you can't carry on a conversation but loud enough you can listen to the nuances in a piece of music even though someone else in the room prefers to talk"

" I find these are very revealing of the specific recording. Realistic vocals, as "in the room with you" were very hard to find. These come close but not quite in the majority of cases. That said they do reproduce good recordings with a very natural sound and live recordings especially sound "live" but I think I still prefer the Dahlquist DQ-20i or the Vandersteen 2C for vocals. Jack Johnson sounded fantastic, Diana Krall always a pleasure to listen to, Natalie Merchant sounded a bit more subdued and compressed, probably more revealing of the recordings mastering and production than her voice. I listened to some choir recordings too and these did not disappoint in the slightest! Wish I actually liked choral pieces"

Can you attribute their unpredictability to anything specific??

 

[orange]

I think the volume of the cabinet is about a third too large for it to express itself well and a MIDRANGE wouldn't hurt.

Why?

Because you are cancelling the image in that range and an off-axis driver, at least a midrange might restore some of the cancellation.

 

[laatsch55]

Oktyabr, wonderful; posts. I hope to understand at least half of it one of these days. There are some folks here that have been waiting for a guy like you so we can bounce some ideas off of. My latest project was done in 3/4 baltic birch and I gotta say I love the wood. Member Skratch had access to a laser cutter and made the bass bin s for a Soniphase SL6, the drivers are the Electr-voice EV-155, they are an impressive bass bin and ca eat up the power. In a direct comparison to my K-Horns( which are K-Inos, because the 15 " driver is now a Crites 1526s, the squawker is now a 2" B & C DCM 50 bolted to a Martelli Tractix wood horn with B & C DC-10 tweets) they sound different and should. I have not finished out the Soni's with midrange and tweet horns but may someday. The Soni's are pushed with a Carver TP-2400 through a Pioneer D-23 crossover.

The K's also have Al Klappenberger's Universal crossovers, which put the stock Klipsch units to shame.

 

[Oktyabr]

Can you attribute their unpredictability to anything specific??

No, not off the top of my head. There IS a technical description somewhere that describes what happens in a horn of this design or similar. In a nutshell, if I remember correctly, the driver displaces a small amount of air into the cabinet (being back loaded horns), relative for the horn size themselves. At lower power some of the frequency response rolls off quicker inside the horn as opposed to what's front radiating from the driver itself. As the horns are designed to accent bass response this is where they *should* roll off at lower volumes... the lower the volume, the less bass response. Crank them up beyond their sweet spot, where the front radiating sound can interweave with that from the horn mouths themselves, and you *should* get cancellation effects with the bass frequencies seeming most prominent as they are entirely generated by the horns themselves. In real world experience though it isn't quite so cut and dried... beyond source material, upstream components, room and room placement, the driver used can make a significant difference as well. That's why the Fostex in that particular pair were specially modified just for that particular build.

If I get the chance to put a similar pair in my living room again I'd be very interested to put a calibrated measurement microphone to work at different volume levels and see exactly where the freqs fall off... maybe a nice waterfall plot.

 

[Oktyabr]

I think the volume of the cabinet is about a third too large for it to express itself well and a MIDRANGE wouldn't hurt.

That's the whole magic in "full range" single driver speakers... they have NO crossover and are a single driver. The cabinet itself, usually computer aided in design, is carefully chosen to create a speaker where a single 8" driver, or a 6" or even smaller, can get very close to the "holy grail" of 10 octaves of sound reproduction, i.e. "full range". None I've experienced hit those numbers yet but most, especially like the Sachiko's in my photos, come a lot closer than you might think. Also because they are a single source they avoid multiple driver cancellations and since there is no crossover (besides the occasional use of a resistor for baffle step compensation) the sound tends to be about as "uncolored" as you can get, very fast, and very accurate.

Here is the crack deale... I mean, WEBSITE, that originally got me hooked on this particular obsession: http://www.frugal-horn.com/

 

[laatsch55]

Very interesting stuff. I'm a horn fan myself.

 

[Oktyabr]

Yeah, I was reading about your K-horns in another thread! I've never actually heard a pair. Have come close to buying some, a time or two, including a pair of Speakerlab clones, but never have made the deal happen. I've always appreciated the build and hey, the original is longest produce model of speaker in history... for a reason? They MUST be good! Can you point me to thread on the mods you have done on yours? With photos?

 

[laatsch55]

I haven't really documented the conversion to the Kino configuration. The 2" midrange was the most dynamic change. these were the Speakerlab version , built from plans. The Crites 1526S woof was made for these cabinets. Really woke up the low end. I had a set of Klipsch K-Horns I bought new in 1976, owned them for awhile then bought a set of Ohm Model "F"'s . Had to sell those due to finances, then built this set. The way these K's are sound way better that the factory K's. The Al K crossover really opened them up. A lot smoother in the frequency hange from one driver to another, almost seamless now.

 

[rtp_burnsville]

Welcome to the forum, very interesting thread.......

I have built a few speakers in the past, mostly musical instrument enclosures. I will have to go on a search to see if there are any photos to upload.

Have toyed with the idea of building cabinets for the stereo upstairs so this is all interesting.

Robert

 

[kevin]

Yea.... Real glad your here !!! Sutton and I built these speakers in my avatar ! Wish I had better pics. Im working on that !

 

[Pure_Brew]

Glad you made it over here. I have read quite a bit about about design and used various software but that was a long time ago. Still have an unfinished Morel/Hivi project that may or may not ever get completed. Pulled the trigger back in the day but stopped abruptly to deal with family matters. Some DIY comes across as inexpensive, but tooling can cost a lot in the beginning especially if you have nothing to begin with.

Now my position is better and I haven't ever really lost interest. But truly I've been busy still with work and teenagers. So for the moment, I've settled for a few fixer-uppers while questing for some fatigue free listening. I just swapped out the caps, resistors, internal wiring and gasket material on these Snell EII's, which have replacement woofers as well. I feel very fortunate that these have come out so well and that I'm able to enjoy them as much as I do.