Speakers

[ScaredyCat]

Does anyone know anything about speakers?

I 'd like to make a set of cone shaped speakers - like the icon used on computers for audio on my lathe.
eg

I don't really know much about speaker design but I was looking at some 4" Dayton Audio RS100 "Full-Range Drivers" as the speaker part. The idea would be to place the speaker in the end (left hand side in the image) .

Just really want to know how likely this is to generate really bad sound and if there's any way to make it better if that were the case. I really would like that design, but will it just be form over function?

.

 

[sunnybob]

Really bad sound...... oh yes. =D> =D> (hammer)
But is this for your living room? or the workshop? over the noise of the workshop they would sound quite good :roll:

 

[That would work]

I've built speakers. Floor standing 3 way using KEF T27 B110 and B139 drivers. They were built to a design known as the 'Concerto'. Subsequently I redesigned the enclosures to make them a little more compact with a sealed enclosure instead of a bass reflex ported design.
They were excellent but too large so I flogged the drivers on the bay some time ago.
The important thing with the cabinet/enclosure is to make it as sonically inert as possible... hence the idea of concrete as an enclosure! There's even more stuff on the Internet on speaker cabinet construction than sharpening WW tools though

 

[Eric The Viking]

The common icon is really a simplified cross section of an old-style drive unit.

To make a complete speaker, you need to mount your drive unit in a box, which prevents the sound from getting from the front of the drive unit's cone to the back too easily (and vice versa). If it can get round the back too easily, the drive unit will sound really thin and weedy, and you'll wonder why you spent the money.

If you want decent bass too (within reason), the box needs to be fairly large and/or with a "port" (a hole) in it, to improve the efficiency of the drive unit at lower frequencies.

You'd probably be surprised at the variety of shapes that can work well. For example, people used to use concrete drainpipes and fit the speaker in one end, back in the 1950s and 1960s, and my father-in-law had some triangular-shaped speakers that didn't sound too bad ( a cheese wedge shape). The ones I've hidden under the bath for the telly are also triangular, but turned inside-out with the drive unit facing inwards, so the sound comes out of a small slot almost at floor level - they work quite well too.

But there are rules based on the laws of physics, together with the characteristics of the drive units, which limit you - obviously you can make any shape you want, but most will sound, er, a bit disappointing.

Actual dimensions I have dodged around, simply because they can be as big or as small as you have space for, within reason. As a general rule though, the smaller the physical box, the less bass there will be. Like all things there are ways around this but that's not a simple discussion.

I suggest having a Google for "hifi loudspeaker plans" (you might add "bookshelf" if you want something compact). It will give you some starting information. If you don't depart too dramatically from what you find and like, you will probably be pleased with what you make.

E.

PS: one slight word of caution - many drive units would be damaged by the sort of finishes we typically use in woodwork. So finish (paint/varnish, whatever) the cabinets you build first, and then add the drive units right at the end of the process, so they're not exposed to varnishes, etc.

 

[Sheffield Tony]

I don't know if I'm being naive (?), but I've always assumed HiFi loudspeaker design involves some maths, several iterations of prototype and tweaking, a lot of expensive test gear and some good ears. They do appear deceptively simple, a rectangular box with 2 or 3 drivers in the front and an optional hole in the back, but I'm guessing by the time you make a pair that sound good, you appreciate that it isn't as simple as you'd expected, and that they didn't actually work out cheap !

 

[That would work]

It does indeed. Tweeters are closed at the back so it doesn't matter really a box as such. After that it's a case of providing a deep enough enclosure (front to back) to allow the sound waves to develop... that's the purpose of a bass port which is a tube that is "tuned" to be a length that corresponds to the actual length of the wave. That's why for an enclosure to allow the bass to be fully heard it needs to be deep enough. For a single full range it should be possible to find out what the optimum volume and more importantly, depth of enclosure. You will also need to put damping material inside the enclosure to minimise sound waves bouncing around inside. I imagine that the manufacturer of the drivers will publish all of this.

 

[thetyreman]

using material that doesn't resonate too much like MDF is a good idea, fill it in with the stuff you find in duvets to cut down on internal resonances, also it's a good idea to round off the edges to minimise diffraction.

 

[chris watford]

If fitting the speakers on the left hand side of the icon, make a box square or oblong and add the rest as an add on parts, not part of the speaker enclosure.

You can buy speaker kits, you make the box, they supply cabinet design,speakers, grills, crossover and wiring bits, and
terminals for cable connection. highly unlikely to find a one speaker design I would have thought.

 

[Racers]

I like woodworking and hifi, but I wouldn't build my own speakers from scratch to much maths and messing around with crossovers etc.
Wilmslow audio do kits that you could modify.

Pete

 

[Eric The Viking]

It still slightly surprises me that Wilmslow has survived Maplins - at least I hope it has!

 

[Racers]

The web site is live.


Pere

 

[xy mosian]

Hi,
Dayton Audio have reasonable guidance for suitable enclosure size.
https://www.daytonaudio.com/product/89/ ... iver-4-ohm

That is if that is the drive unit you have. If not there are many others listed, I assume with similar detail available.

The maths that are mentioned are most likely based upon a papers written for the Journal of Acoustic Engineering, American, by Theile. The papers were titled 'Loudspeakers in Sealed Enclosures', and, 'Loudspeakers in Vented Boxes', or Enclosures, I cannot quite remember. Both of those papers require detailed examination of some parameters of the drive unit concerned . Luckily, without extensive research, it seems that Dayton may well have provided that detail within their literature.
I did a fruitless search for a web version of those papers. However there appear to be quite a few calculators for home use. That is, plug in numbers get out different numbers which may be more use.

My first 'HiFi' speakers, crikey 1965, were 3foot long 12" diameter concrete drainpipes. With a vent and being driven by an upward facing 10" full range driver. The pipes stood vertically. They were a long way from what I later learned to be HiFi. They were however spectacular compared to the average audio of the time.

Have fun, the only person who can decide if the sound is good enough is the client, you.

HTH, xy.

 

[ScaredyCat]

Ok,

Thanks everyone. Looks more like a really long term project for which I'll need to do a lot more research. :shock:

.

 

[Racers]

Have a look here.

https://www.pinkfishmedia.net/forum/thr ... em.112905/

These are highly rated.

Pete

 

[u38cg]

The usual recommendation for people who want to build their own hifi speakers is Paul Carmody's designs, which use commercially available parts and sound good, as in hi-fi good. And, crucially, they are properly designed, which is a surprisingly complex subject.

https://sites.google.com/site/undefinition/diy

 

[Robbo3]

I like woodworking and hifi, but I wouldn't build my own speakers from scratch to much maths and messing around with crossovers etc.
Wilmslow audio do kits that you could modify.
Pete

Glad to hear Wilmslow Audio are still going.
Back in the 70s or 80s I built a pair of speakers following the plans from a hi-fi magazine that required Richard Allen units & crossovers supplied by Wilmslow Audio.
Parked my old BSA Bantam outside Oxford station & took the train to Wilmslow having to walk between Snow Hill & New Street stations in Birmingham because they weren't connected at that time.
Can't remember the travel cost but it must have been cheap or I wouldn't have done it. As far as I recall, I was there & back in about 5 hours.

 

[Eric The Viking]

I still have a bass guitar cab built to one of their designs, and with a Fane driver from them. It still works just fine, although my bass playing doesn't!