A sample of my DIY speakers

Jim Shearer

Per @Verb’s request, here are a couple pics of speakers I have built. Note that most here would not particularly like the speakers I build. That’s the thing about DIY, you design & build to suit your own preferences and listening space. Most of what I build are single full range drivers, which avoid the issues associated with crossovers, and which provide single point source (although this can be achieved using concentric drivers as Tannoy does). If you want high SPLs and big, thumping bass, then don’t bother thinking about SFRDs; the compromises in lows, highs, and volume will leave you disappointed.

Most people aren’t bothered by the problems arising from multiple drivers and crossovers, such as phase errors. I doubt many of you have ever heard a good SFRD, but I am sure at least some of you have heard Tannoys; if you find something special there, it’s probably due to the concentric drivers. And you may be candidates to join SFRD crowd.

Below (in separate posts)are pics of the three systems in our bedroom and the two in our living room. Yes, my wife is extremely tolerant of my audio obsession, although she has now reached her limit (and the physical space limitations of our home), so that if I build anymore speakers, they must have a home to go to before I start cutting lumber.

Builds have been documented on DIYaudio, but I don’t know if it’s permitted under terms of service to give links. Designs were modeled using Martin J. King’s MathCAD worksheets (no longer available).

Cheers, Jim

Jim Shearer

The bedroom systems:

The really tall ones are called ‘BIB’ or ‘Bigger is Better’. While it is called a tapped horn, it falls somewhere between a true back loaded horn and a transmission line. The low freq limit of a BLH is defined by the size of the mouth, but here the room boundaries act as an extension of the mouth. When I measured the in-room bass performance, I was surprised to find a flat octave from 25 to 50 Hz, which I attribute to the room being part of the horn. These BIBs are 89” tall, and use Mark Audio Alpair 10.3 drivers

The short floor standers are open baffles, and are a variation on Martin J. King’s small, passive OB project. Drivers are Eminence Alpha 15a and Fostex FF85K. OB provides a different presentation than box speakers. Some love it, some hate it. I encourage you to get your ears on a good pair of OBs and judge for yourself. Panel speakers like Magnapan are very similar. (Side bar: these drivers aren’t as picky about amplification as Maggies.) OBs won’t give you chest thumping bass, due to the way they load the room, but I find that drums are rendered much more realistically than with box speakers. Bass radiating from the front and back results in cancelation to the sides, such that room modes can be less of a problem. And as an added bonus, rooms above and below your listening room will experience less ‘bleed over’. I would think this could be a great advantage for those who live in apartments and have to be considerate of neighbors. I also note that these speakers sound exceptionally good at low volume, an area where many speakers do poorly.

The little stand mounts are Fonken Prime using Fostex FE-127e drivers; designed by Dave Dlugos. The long, narrow vents perform differently from circular vents. What bass there is, is quite articulate.

Jim Shearer

The living room systems:

The tall, thin speakers are Metronomes; a design by Scott Lundgren which I adjusted for the Fostex F120A driver. The F120A sound truly mediocre when driven by almost all SS amps; put tubes on them and it’s like the heavens open and the angels begin to sing. I built a dynakitparts.com ST35 to drive them. This is my jazz system. Not so great for large scale orchestral music.

The larger speakers are what I call Pappa’s TL; a transmission line configuration that goes back to the 1930’s (IIRC), which I tuned for the Fostex FF225wk. The FF225wk lacks high freq extension, so there is an Eminence APT-80 horn tweeter sitting on top, pointed into the room corner. Tweeters are in ‘socks’ made of black grill cloth so that they can be moved around to optimize them depending on room placement; ROT: point them anywhere but at the listener, as phase relationship between the FF225wk and the APT-80 would be untenable if pointed at the listener. I alternate between driving these with Nelson Pass Amp-Camp-Amp 5w monoblocks and a 2.5 wpc single ended pentode amp. The ST-35 doesn’t sound so good with these—bass is a bit loose.

tonyb

Looks nice bro, I see you have a one track mind when it comes to color though.

J/K- really man, looks awesome.

Jim Shearer

Hey Tony,

I admit that I tend to use clear polyurethane. Don't favor oil, as it is too easily damaged. (We aren't going to talk bout my experience with finishes getting damaged...). All are made from plywood, but veneer varies.

The BIBs are maple, the OBs are birch, the Fonkens are red oak. Stands for the Fonkens are solid red oak.

The Metronomes are also red oak, while the PTLs are aromatic red cedar. I let Marian chose the veneer for the PTLs. Bit of a mistake, as the cedar is really tough to work with; so brittle!

mhardy6647

I like those kinds of loudspeakers.




Teeny-weeny Onkens -- adorable.

mhardy6647

There are some scaled down Klipsch folded horns (LaScalas) floatin' around out there... someplace.



source: https://community.klipsch.com/index.php?/topic/138580-minature-klipschorn-la-scala-or-jubilee/

dromunds

Looks really good, I like the natural wood look

mhardy6647

@Jim Shearer
The thing I forgot to do before is to say that all of those look really, really nice!

FWIW: Here's another Lilliputian LaScala (let's hear Elmer Fudd, or even Barbara Walters, say that!):

https://community.klipsch.com/index.php?/topic/186359-runt-la-scala/

verb

OMG Jim! Those look fabulous! The craftsmanship looks exquisite!

I understand why you will never sell em! Unless of course to Verb!

jumpindick

Those are some nice looking speakers. Do you do woodworking yourself?

Jim Shearer

Thank you all for the kind words!!

I do the wood working myself. It looks better in the photos than in person--I am no Norm Abrams, nor do I have access to the New Yankee Workshop.

I do my best to make presentable speakers, but not everything gets my best effort. Here is a comparison of the prototype for the PTL (made from OSB, with is closer to plywood in performance than MDF) and the finished product.

Jim Shearer

And a couple pics to show 'in progress':

steveinaz

Very nice!

mhardy6647

it all looks great to me; even the prototype.

Nightfall

What's in the little ones in the first pic that look like they're vented down the front sides? I've been having a thing for bookies lately.

mhardy6647

they're teeny-weeny, itty-bitty Onken-style enclosures

https://www.planet10-hifi.com/fonken.html

Jim Shearer

@Nightfall,
As Mark said: they are P-10's Fostex Onken (Fonken) using Fostex FE-127 (4.5") drivers (no longer available). But Dave Dlugos has a bunch of those Onken type designs, mostly for Mark Audio drivers now. I also built a pair of micro-Fonkens using Fostex FF85k (3.5") drivers which are in daily use in our dining room.

mhardy6647

Dave Dlugos is a great guy! He's had some pretty serious health issues in recent years, but he's still around (thankfully).

The only thing of his I have, come to think of it, is a pair of his phase plugs for R/S 40-1354 twincones.

I have them installed on the drivers in my ML TQWTs (Bob Brines' design, not Dave's) and they did a nice job of smoothing out the treble and at least subjectively extending the HF response (?!).

Jim Shearer

Serious doesn't begin to describe Dave's health problems. He is the only one I know who has had an aortic aneurysm begin to rupture and lived to tell the tale!

I was never bold enough to cut out a dust cap and install a phase plug. I can say that a bit of fiber stuffing between the whizzer and main cone did fix some issues. Below is an FE-167e with the bearded whizzer treatment. Note that the 167 had a hole in the dust cap to eliminate some resonance.

mhardy6647

Jim Shearer wrote: »

Serious doesn't begin to describe Dave's health problems. He is the only one I know who has had an aortic aneurysm begin to rupture and lived to tell the tale!

Yes, indeed. We lost my father-in-law to one in 1986.
I have followed (and still do) Dave's progress via the fundraiser page his wife and friends started -- but I didn't feel that it was my place to go into details in the context of your speaker thread.

I was never bold enough to cut out a dust cap and install a phase plug. I can say that a bit of fiber stuffing between the whizzer and main cone did fix some issues. Below is an FE-167e with the bearded whizzer treatment. Note that the 167 had a hole in the dust cap to eliminate some resonance.

Ahh, the [Lowther] 98 cent tweak!
https://www.diyaudio.com/forums/full-range/134206-fr-taming-tricks.html

Yes, I've done that before with some success on tizzy-whizzered drivers, too. I've also Dammar'd Radio Shack 40-1296 (Fostex FE-103 OEM) cones, too, in a modestly-successful attempt to tame their tizziness. The things we do for fullrangers.



FWIW, I only had the chutzpah to do the dustcapectomy because I had several spare pairs of the drivers in question!

mhardy6647

Oh, boy -- here I go...

The above-mentioned 98 cent tweak, from the old Lowther America site, via the Wayback Machine.

https://web.archive.org/web/20080331190803/http://www.lowther-america.com/tweaks.htm

Whizzer Damp[-]ing

Without going into the technical mumbo-jumbo, one of the things that occurs with the old style Lowther cones is that the whizzer resonated at about 2 KHz, creating what many referred to as the Lowther shout. This has been addressed by the new cone design, but since few of you have the new cone design, lets talk about what can be done.

The easiest thing to do is to turn the drivers so that they face 15 to 20 degrees away from your listening position.

I personally tried and liked the effect of Marc Wauters 98 cent fix. This consists of placing a lightweight piece of foam between the outer edge of the whizzer and the middle of the main cone. As a result, it drastically reduced the resonance peak of the whizzer. Sadly, Marc has recently removed his site.

Another approach is to take 2 cotton balls for each driver. Pull them out, and then twist lightly so that you get a 2 or 3 inch long cylinder. Then place this between the whizzer and main cone. It is not as effective as the Marc Wauters fix, but does create a noticeable drop in the upper midrange peak.

You can purchase the new style phase plug without upgrading the cone. It does make the highs very directional, so that you must listen with the speakers aimed directly in line with your ears.

I'll stop now -- back to our originally-scheduled topic; @Jim Shearer's gorgeous loudpeakers!

Willow

I don't know where to start. Amazing job, visually because I'll never hear them. I wouldn't have the slightest as to where to begin making my own and getting them to look as nice as yours. Keep up the great work.

Jim Shearer

Thanks!

I started by using the dimensions for a Fostex FE-108eSigma Metronome as given by Dave Dlugos. Using circular saw & jig saw.

When I saw that I was going to be building more, I acquired a small table saw and a router. Router is key to so much! Good not only for cutting holes for drivers, ports, & terminal cups and bevels & round overs, but also for getting long edges perfectly straight and clean. Even with the table saw, I couldn't get a perfectly straight edge several feet long. I find a good straight edge (maybe an 8' piece of lumber, maybe a metal straight edge) and use that with either a flush trim bit or a pattern follower bit.

And then learning how to veneer is another whole adventure!