Wideband Midbasses

[Taterworks]

Hi, everyone.

I've got a quick question. I've been reading a bit lately about designs like the Alegria Audio Ling that use a full-range driver crossed over to a tweeter around 10,000 Hz (outside the vocal range), or designs like the EgglestonWorks products that use direct amp-coupled midbass drivers.

One driver that's caught my eye in the past for its strange design is the Tang Band W6-789S 6.5" woofer. The reason why is its remarkable dimpled Santoprene surround, which has a honeycomb-cell pattern molded into it.

http://www.partsexpress.com/pe/showd...number=264-852

The driver itself only handles about 15 watts RMS, but it's got a high 92dB 1W/1M sensitivity, and a frequency response that naturally extends to 10,000 Hz with a nice roll-off. I think it would mate well with a planar isodynamic tweeter of some sort serving supertweeter duty, and with a simple crossover network that direct-couples the wide-range midbass to the amplifier and a first-order network with an L-pad on the tweeter. Can anyone think of a reason not to try this?

Another question I have is, at what frequency will the 6.5" woofer's coverage pattern shrink to less than 20 degrees horizontally? I think that's the point where a speaker wouldn't be useful for home theater, though it might still be useful for music.

Any insights you can lend would be greatly appreciated. Cheers!

Rory

[MaVo]

just a few thoughts...

- depending on your age, there wont be much above 10khz
- because of the small wavelength, crossing to a tweeter this high will produce alot of interference patterns.

- make an experiment: listen to a 10khz and maybe a 15 and 20khz since wave through your headphones and then judge for yourself if you really need the extra tweeter. (you can use the free waveeditor audacity to generate the waves)

[crazyhub]

On-axis TB curves are excessively smoothed; I don't see any reason this 140cm2 SD could provide an extended 10Khz response; from comparisons to some vifa of similar SD and MMS, I guess such a driver should begin to shrink near 3.5/4Khz at 20° off-axis.
IMHO this TB is well suited for a first order low-pass at a classical 2.5-3Khz...it is by no means a full-range or even an extended range driver.

[D OB G]

Just a comment on 10 kHz.
The new Dali has an integral dome/ribbon HF driver.
The ribbon comes in at 14 kHz (don't know the slope).
The dome is supposed to go to 20 kHz.
I don't know how they level match, or whether they do at all.
However if the ribbon is covered, it doesn't sound as good.
It literally sounds as if it is "not as extended".
(I'm 48 and I can still hear the 15 kHz scan of an old black and white TV- up close!).

[Caferacer]

That driver catches my eye from time to time too. Especially when it's on sale for $26! But I agree, that curve is optimistic. I doubt it's that smooth or extended or we'd all be using it already.

[sandstorm33]

Originally posted by Caferacer
That driver catches my eye from time to time too. Especially when it's on sale for $26! But I agree, that curve is optimistic. I doubt it's that smooth or extended or we'd all be using it already.

Look what happens to impedance above 1.5K . Good driver for ZEN amps coupled with an efficient mid tweeter. Crossover 2K. 12db. In fact go to Claudio Negro's website and build yourself a Double Chamber Box. You wont believe the results.

[critofur]

I ordered four just in case they're good. Mostly what caught my eye (other than the obvious smooth response, which might be BS, since Tang Band is not known for their honesty when it comes to FR charts!) is the high sensitivity. Will be nice to not have to "pad" the tweeter at all and end up with some efficient speakers w/out having to use prosound drivers.

These might be good drivers for a three way using 1st order crossovers if you can find a good 3" mid which rolls off smoothly on both ends?

The mid could be less sensitive and you could do the kind of crossover where the woofer and the tweeter overlap some, but are "spread apart" more which leaves a broad dip in the middle which is "filled in" by the mid. What is the term for that, I don't remember, I saw somebody on the HTGuide forum doing an x-over that way. Hmm...

Named after some guy, Duelund? Ah, here's the guy: http://tkhifi.homepage.dk/due3vejs/d...simu3vejs.html


Hmm, that's not quite what I meant though - let's see...
Here it is:

The image is from the HTGuide forum which I still look at once in a while, but no longer post there, due to some people (and one of the mods) there really being jerks

The Tang Band W6-789S top end looks smooth enough to cross very high, but, because of it's size I would cross it lower than you might first want to (if you were only considering the FR chart) to avoid narrow dispersion. But, the smooth top end would allow one to not need steep slopes to avoid the spikey top end cone breakup of drivers such as the PE RS series metal cones.

I'll have to finally get my measurement setup working once I get these in ~ I've got a half dozen or so different drivers I need to measure and I might like to get some speakers done in time for DIYINDIANA

[crazyhub]

Funny!
This thread began with a lowpass idea of 10000hz and presently reduced to 600hz. Now anybody wanting to cut at 200hz?

[crazyhub]

Originally posted by critofur


These might be good drivers for a three way using 1st order crossovers if you can find a good 3" mid which rolls off smoothly on both ends?

The mid could be less sensitive and you could do the kind of crossover where the woofer and the tweeter overlap some, but are "spread apart" more which leaves a broad dip in the middle which is "filled in" by the mid. What is the term for that, I don't remember, I saw somebody on the HTGuide forum doing an x-over that way. Hmm...

Named after some guy, Duelund? Ah, here's the guy: http://tkhifi.homepage.dk/due3vejs/d...simu3vejs.html


Hmm, that's not quite what I meant though - let's see...
Here it is:

I remember that some 30 years ago this "mid filling the dip" type of filter was reknown as the only way allowing a good square signal reproduction. This type of filter is what I ended up with on my latest project. Just symetrical and asymetrical slopes on my last project so not really first-order type. And it works very nicely to my ears, very "open", without the harschness or whatever other flaws related to stiff cones drivers (I use Accuton and Focal beryllium).

[Taterworks]

My real interest in these midbasses is that they'd let me build a two-way nearfield monitor that could achieve high output (~105dB) with only 15 watts input, with low-power amps designed for use with PCs, like the NuForce Icon or the SilverStone Ensemble 01/02 combo.

Another potential tweeter candidate is the Hi-Vi RT1L -- the round planar isodynamic tweeter on Parts Express. Even if these drivers don't go flatly to 10kHz, they'll likely make it high enough to cross over to the RT1L where it won't be laden with distortion.