Jordan 6T small enclosure help

[Redshift187]

I have acquired a pair of drivers that read Jordan 6T on the back, which seem to be either J6T's or Alpair 5's, probably prototypes. The Fs measured at 122Hz.

I have a woofer that I will use to fill in the low end, probably crossing over somewhere between 125Hz and 200Hz.

I would like to build a pair of enclosures that fit on my desk for use with my computer. I have a fair bit of space available, something less than 20L and taller than the other two dimensions would be ideal. The mFonken looks like a reasonable enclosure size, with the Fonken being the upper limit.

Any suggestions on an enclosure design would be very helpful.

[chrisb]

Originally Posted by Redshift187

I have acquired a pair of drivers that read Jordan 6T on the back, which seem to be either J6T's or Alpair 5's, probably prototypes. The Fs measured at 122Hz.

I have a woofer that I will use to fill in the low end, probably crossing over somewhere between 125Hz and 200Hz.

I would like to build a pair of enclosures that fit on my desk for use with my computer. I have a fair bit of space available, something less than 20L and taller than the other two dimensions would be ideal. The mFonken looks like a reasonable enclosure size, with the Fonken being the upper limit.

Any suggestions on an enclosure design would be very helpful.

The 2 drivers are very similar indeed - no surprise considering their history. Anyway, while they should really be considered wide band mid/tweeters and a higher XO might be advisable for larger venues/far field listening, they'd likely work fine for your purposes.

Note that even the "full size" Fonken Prime which has been quite successfully adapted to a wide range of Mark Audio drivers is approx 1/3 less than your figure of 20L (i.e. ~13L), and the mFonken is approx 2.

There is a quite decent performing little desktop design for the Alpair 5 by Henkjan that might be worth looking at.

desktop speaker with Markaudio Alpair5


there may have been other threads discussing this little cutie since 2 years ago

[planet10]

What you have would be the Jordan labeled Mark Audio built J6T (J short for Jordan) -- looks like a silver Alpair 5 with flying leads? It is the precursor/prototype of the Alpair5

I would suggest an XO > 200Hz for these at a guess. I have an Alpair5/woofer project just awaiting assembly. I loaded the A5 into a 4" piece of plastic pipe (i'd have to measure how long they are) transmission line, and stuffed them as you do a midTL. Bass will be provided by a pair of EL70eN each side in ThirlmereR

Gregg-the-Geek did a J6T + Silverflute 5 1/4" woofer project -- on diyA IIRC -- that XOed much higher.

dave

[bearberry]

Tyler, nice to see you getting started on this already!

John

[Redshift187]

Originally Posted by chrisb

Note that even the "full size" Fonken Prime which has been quite successfully adapted to a wide range of Mark Audio drivers is approx 1/3 less than your figure of 20L (i.e. ~13L), and the mFonken is approx 2.

There is a quite decent performing little desktop design for the Alpair 5 by Henkjan that might be worth looking at.

desktop speaker with Markaudio Alpair5

Thanks. My math might be way off on the volume, I was having trouble figuring that out (it should be so simple!).

Originally Posted by planet10

What you have would be the Jordan labeled Mark Audio built J6T (J short for Jordan) -- looks like a silver Alpair 5 with flying leads? It is the precursor/prototype of the Alpair5

That's exactly right. Thanks for the ideas. I'm looking for straightforward, but not necessarily too simple. For the moment I have them mounted in crappy ported enclosures that some other speakers came in.


Thanks, John. After the audio meet the other day, my ambition level has gone way up

[planet10]

Originally Posted by Redshift187

My math might be way off on the volume... (it should be so simple!).

A rectangular box is simple. Take the internal dimensions in cm, wxhxd=Volume (in cm^3). Put the decimal place where the first comma goes and you have litres (aka divide by 1,000)

going the other way... to start let's do a Golden Ratio (=GR ~ 1.618) box. Take the cube root of the volume. Set it to width = w, height = w x GR, depth = w / GR.

Other aspect ratios are a bit harder. You can use the cube root as a starting point. Try to keep the aspect ratio of panels close to irrational numbers (be careful with root 2).

dave

[planet10]

Originally Posted by Redshift187

Thanks for the ideas.

More examples here (A thread for Tysen and variations on FAST) and following the branches.

dave

[Redshift187]

Excellent, lots of reading to do (not being sarcastic, I actually like learning by reading).

I think my problem was in using mm, and doing it in my head, I probably lost or added a decimal place in the conversion to litres.

[eeyore]

Built 6 for my HT setup, near field use, 150hz could be okay. I reckon any box shape, sealed at least 1l or more. Can try as many different shapes as possible, or try a shape to optimize your material choice.

[Redshift187]

Okay, so here's more info as I've read and kind of started putting things together in my mind.

1) These will be near field
2) Mid range / vocals high priority
3) There will be a separate (sub)woofer (2.1 type setup)
4) Passive crossover (either LLXO of some sort or using the soundcard to do that)
5) 10L or smaller with around 5L or less being ideal (width limited to 150mm)
6) From what I've read crossing them around 300Hz would be better than lower

This is my first speaker project, so sealed would obviously be easiest to build, but I think I can find some local help for more complicated designs. I was reading in another thread about the mMar-Ken6 and was wondering if it might be a suitable design with some tweaks?