A new little pair of DIY Monitors....

Folks,

I knocked up something for my second system, described over at AA in more detail:

http://www.audioasylum.com/audio/tweaks/messages/132992.html



They are doing pretty decently for something as small as that.

Ciao T

 

a nice chess set

 

Nice use of a bread bin

If my local Wooly-worths sells them I might make something out of the W3-871S' I have lying around. What is its volume?

Good job!

 

Hi,

My thanks. I thought so too.

They do something smaller in their collection for icky bicky dinky things, the breadbins are 12 Liter internal net volume (accounting for my 18mm front panel and shelf brace).

You know, the NeoFone has a surprising dynamic range for a 5" Driver, just playing some dance at fairly high level and they do tend to compress a little on peaks but not in a bad way.

I could imagine a 4-Pack of these giving serious SPL's.

When you come over you can have a listen and give them a measurement....

Ciao T

 

12L Thats exactly what I wanted! 20cm x 20cm x 30cm?

I have a pair of the Tangband and also a pair of 7" Dayton cones. I thought I might put the Dayton in the bottom and give it a lowpass filter to extend the bass (they have good excursion) then cross them to the Tangband at about 200Hz. I know there would not be much SPL ability with that, but they should sound good in the near field.

I look forward to hearing your new babies  The NeoFone has caught my eye a few times.

 

Hi,

315 X 215 X 175mm HWD internal, allowing for an 18mm baffle glued to the bottom.

Ah yes, that makes some sense then. The TB's in 12l wiuld be a bit much.

See you in two weeks or so?

Ciao T

 

Okay I'll lug the laptop/microphone and bits long.

 

''the speakers sound well balanced, with a bass that next to open baffles is a little boxy and lumpy, but quite tight and precise..''

That's precisely what happens when you put a drive unit into a bread bin.

''Thus each dimension is subdivided into a 1 & 1.618 long part and any remaining resonaces are spread out.''

Thorsten do you know exactly how the resonances are 'spread out' eh ?

 

Hi,

Only if you want to, you don't have to. I should be getting an EMU 1616M shortly, that should make it easy for my laptop to measure all and sundary as well....

Ciao T

 

I'm happy to bring it if you don't have the EMU yet. Looks like a nice little interface. Are you not tempted to go USB though?

 

that should make it easy for my laptop to measure all and sundary as well....

'All' is the operative word. The trouble is, it will be highly room dependant.

 

Simon,

Thanks for the offer. I might need it for my other project, which has a more elaborate crossover and might need some finetuning.

What was funny, the Woolworth breadbox is less resonant than the boxes build by a professional carpenter from 18mm Birch Ply, I needed a lot more bracing for that one, then again, the box is around 50% bigger in all dimensions. Still.

The reason for the EMU is actually simple. It has this breakout box which has very high impedance inputs with a lot of gain, just what the doctor ordered if you wat to measure audio gear to a reasonable degree and you do not want to shell out for the Audio Precision Two.

And I found nothing at that kind of price and functionality/data that was USB. So to me the Mike Pre and phantom power that enables easy speaker measurements are a side benefit, not the actual objective....

Ciao T

 

Nice work !

 

That's what I call "using your loaf" =)

Nice job there, Thorsten.

 

Hi all,

£72 per pair!! Cheap.

Would these work in the Jordan VTL enclosure ?

Thanks,

Lee

 

Hi,

You need to add the Foster Ribbons. They bring the total to around £ 130.

Then add £ 30 for a pair of Breadboxes and around £ 10 at B&Q (MDF, cutting, glue, plumbing pipes etc.) and if you don't have binding posts & capacitors at hand maybe another £ 10 for the rest.

Still, at £ 170 in materials and no more than 4 Hours build time (for me anyway) not to be sneezed at.

I suspect yes, but you may have to experiment with the damping etc.

Ciao T

 

3DS,

Thanks for the info. I wouldn't bother with the tweeters as I like full range drivered speakers, or rather the lack of crossovers.

I'll compare the graphs for these and the Jordan drivers to see how similar they are. Presumably, and I know not what I'm talking about here, if the drivers' characteristics are very similar, then the same enclosure should work...er....right??

 

Hi,

I do not put a crossover on the fullrange driver. The ribbon has around 3db more sensitivity and is crossed over at 30KHz/1st order. What it actually does is not to take over the treble from the fullrange driver but to broaden the HF radiation in the horizontal plane only at high frequencies, where the Driver itself is subject to extreme beaming and you must be straight on axis.

It is quite audible on cymbals and percussion.

Not quiet. You need to look at the so-called Thiele small parameters. A transmission line is however somewhat more tolerant to different tuning than a reflex box and the differences in parameters are reasonably modest.

The NeoFone is a little more efficient and can handle around 5db more low frequency input than the JX92S. It certainly sounds good. It CAN keep up in the big rig without sub and makes musical sense with surprisingly robust low frequency output.

Ciao T

 

''Thus each dimension is subdivided into a 1 & 1.618 long part and any remaining resonaces are spread out''

Show me your esoteric calculations and I will show you where you have gone wrong.

 

3DS,

Interesting stuff, many thanks.

"....the Driver itself is subject to extreme beaming and you must be straight on axis...."

Is this generally true for all fullrange drivers? I currently use fullrangers in a small dedicated room, so listening on axis is no problem and the norm for me.

May have to knock together some trial VTL cabinets, test damping etc, then build a proper pair once the best sound is found.

Thanks,

Lee