TB 2" FR project...loading ideas?

[mondogenerator]

Ive just bought some of these lil 2" TBs:

http://www.tb-speaker.com/detail/1230_04/w2-800sl.htm

Im thinking of a small computer speaker set up running fullrange, OR some kind of FAST system. These drivers may not be optimal in either configuration, high fs etc but the overall flatness of the published FR, low mms, and the cheap price swayed me into a cheap(ish) FR project.

fs = 160hz
qts = 0.25
vas = 0.22litres

judgin by these ts im planning either sealed box or aperiodically stuffed TL, to assist in rolling of LF , to integrate with a subwoofer.

anyone have any other ideas, or possible advice?

[mondogenerator]

the low qts and high fs mean that in winisd i need a 30cc 'box' to get Qb of .72, AND A -3dB point of 450hz.

not sure thats much good for a FAST design? maybe im wrong....

increasing box size to .2 litres gives me a Qb = .35, and a nice roughly 6dB/octave roll off, with the -3DB at 500hz instead.

any suggestions or have i bought myself some nice wide band tweeters for something?

[badman]

Nice wideband tweeters, yep. You can do a 500Hz Xo, but you'll need to assist the acoustic slope electrically. I'd probably go with a stuffed, open backed box, and a low order 1kHz XO with a very good midbass.

[norman bates]

I've wanted to do a short line array of 4 x 2" drivers (vertical array).
The 800sl had good comments from Japanese users, but the low qts seems to be a deal breaker. Maybe a resisitor in series can help.

I don't believe the graph on the partsexpress site, but I do believe this one. Notice how it falls off on an infinite baffle.
http://www.solen.ca/pdf/tangband/w2800sl.pdf

Here is a quote
"TangBand W2-800SL
This unit is a unit other than 5cm, aging (RUNNING) will take longer to come up with a very smooth sound to get used to once. Is it because of the magnesium diaphragm is a great sound that is both sharp and smooth. Depict a very good habit of the amplifier. 5cm As is true of the other units, 5cm baffle with minimal skills and spatial representation of the diaphragm will not win any other speakers? HDB-800R In particular, HDB-800R make a noise, so useless, as you also would not look at the graph below, in horribly flat, and sharp. "
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They must measure the driver a couple of cm from the cone to get the response that flat.

I think the 803sm would work better as a 2" nearfield and the qts = .4, although wolf commented that the Fs was more around 220hz instead of Tang Band's listed 160hz. Zero bass.

Then again, the new gen2 alpair 6 paper cone should be better.

Norman

[woody]

I know a qts of .35 looks like a 6db/oct roal off but it's realy 12db/oct . Just look at
what happens way below resonance.

[mondogenerator]

Originally Posted by woody

I know a qts of .35 looks like a 6db/oct roal off but it's realy 12db/oct . Just look at
what happens way below resonance.

i meant QTbox = 0.35 ie very low. the roll off IS 5-7 db/octave with this overdamped tuning, the thing that would stop me using this alignment would be the overdamping, and the possible over excursion at lower frequencies, when compared to a optimally damped alignment.

To the wise one, who posted about the series R to increase Qts; many thanks, THAT particular idea had escaped me completely. Im pretty sure a small resistance would help me tune the driver better.

[mondogenerator]

the lil 2" TBs arrived in the post today, courtesy of parcel-force, and in perfect nick. I had to call short a Christmas shopping expedition i had to connect these things up and have a mess about with them.

out of the packet and connected straight to my amp they sounded a little hard in the uppermost octave, as i expected to some degree, from the published FR plot/s.

next i mounted one on a baffle about 2ft square, and the sound was far more balanced, than just the chassis alone. however i have to say i have some doubts about running them fullrange as the xmax is only 1mm, so in order to allow a slighly louder testing session i placed both together vertically on the same baffle, running the other speaker channel thru the ~0.6Qb sealed box with visaton al130 in it as a test box. this was rolled off with somewhere between 3 and 5 mh, although ive added 50uf cap and playing with resistors, so the mini experiment is in a state of flux at the mo!

i am however pleased with the sound of the drivers, most particularly the pair in series, and maybe an array of 3 or more maybe considerable. i know little about line arrays tbh, but with the 2 drivers alone i didnt experience any severe combing. mind you im not sure if less than 3 drivers exhibit that behavior.

[chris661]

I was going to say that, if you're looking for a FAST system, I have 4x Visaton W130S for sale.

Still, you've got the Al130 drivers, so there's not much point.

Good to hear you've got them up and running.

[norman bates]

you can probably get away with 4 of the 800sl in a vertical array assuming you are the only one listening to them.

Remember 4 of the 2" drivers have slightly less area than a 4" driver, so running a fast system crossed at 200hz may be feasabile. I found 200hz 24db with 114cm2 area acceptable for occasional cranking yet keep the midrange magic of full range drivers. And the falling response may be a problem regardless of sealed /ported /any box.

Here is the nonsuch4 using 4 x bandor 50mm units (run wide open, no baffle step) with a woofer (or sub, I can't remember). The centers are 2.5" apart. Each bandor cone area was around 26cm2 each (larger than a 2"). Total area is around the area of a single Alpair 10.


I play with a dual 4" tang band and combing is a pain for everyone else but not at my chair.

I look forward to your comments.

Norman

[borispm]

This reminds me of the Audience bipole arrays. Should be fun to have 8 drivers or more in bipole array. Maybe with some simple passive equalization to boost the midbass, so that it's f3 can be made into 100-120Hz range?