New (?) 2 1/2 SB Acoustics full range drivers

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Not tried it, but I've used or worked with a number of SB's drivers, and they're generally excellent examples of their type. This is a very small driver indeed though (obviously) so no miracles. From the FR graph like they've tried to concentrate bell modes to a single large peak -fair enough, different design approach. No sign of it (or much else for that matter) on the impedance trace though; probably need a higher resolution for that.

For the money, it's probably the equal of some of the Peerless / Vifa models of similar size. But -you can get the 3 1/2in Vifa TC9 for less than half that, and its fiberglass cone equivalent for about the same price, both of which on paper appear to equal or exceed the SB's performance, while for a bit more you could have the stonkingly good FF85wk. So I'm not sure what special advantages this unit brings to the table.
 
thanks for replying scottmoose!

I don´t know, but I always had the impression (by looking at the FR charts), that the tc9 lacks some high end resolution... so I guess I´m pretty much wrong here fortunately so? I really don´t mind spending less and have the same amount of performance! :D
 
Founder of XSA-Labs
Joined 2012
Paid Member
Neat looking driver, the basket and vented spider make it resemble a mini aluminum coned TC9FD, which, as all of you know is one of my favorites. I do not see the freq response or sensitivity as any smoother than the Vifa. The one difference is the lower Qts and smaller Vas which may be useful in keeping the cabinet smaller when building a vented box.

What are those 5 radial ridges on the cone? Stiffeners to force breakup into the single big peak? The one breakup mode is bigger than the Vifa in amplitude at 17dB deep, and that may show up as a nasty 15kHz ringing on an impulse response. Those are really hard to get rid of and will give a false airiness to the sound signature or sibilance on certain notes. I haven't heard it of course, but that is my experience with a big peak like that in the HF region.

The response of the TC9FD is provided here from 200Hz and up and gives reasonable extension up to 18kHz. It is not going to sound like a good dime tweeter that hits 30kHz, but then my ears don't hear anything above 16kHz anyway.

393264d1389529305-nautaloss-ref-monitor-nautaloss-ii-subs-room-freq-final-1.png
 
Last edited:
thanks for replying scottmoose!

I don´t know, but I always had the impression (by looking at the FR charts), that the tc9 lacks some high end resolution... so I guess I´m pretty much wrong here fortunately so? I really don´t mind spending less and have the same amount of performance! :D

I'm not a huge fan of the TC9. I don't dislike it, it's certainly very well engineered, and for the money you really have nothing to complain about. But I'd tend to concur about a lack of resolution at the top. I prefer the fiberglass model on that score. Neither match the FF85wk though -it's more expensive (these things are relative), but worth the extra. This is one of those cases where you get what you pay for. You can't necessarily force the Fostex to go quite as low, but I'm not a big believer in forcing tiny drivers to produce bass anyway (except arguably in an extremely large horn, which have their own compromises). They rarely thank you for it. Depends what compromise you favour.


What are those 5 radial ridges on the cone? Stiffeners to force breakup into the single big peak?

Pretty much.


The one breakup mode is bigger than the Vifa in amplitude at 17dB deep, and that may show up as a nasty 15kHz ringing on an impulse response. Those are really hard to get rid of and will give a false airiness to the sound signature or sibilance on certain notes. I haven't heard it of course, but that is my experience with a big peak like that in the HF region.

Right. Depends where they are of course & the amplitude, but even out of the nominal hearing BW they can cause problems lower down; probably IM related. Isn't always obvious from the usual distortion measures, and not everybody is bothered by it, but for others it's a constant irritant.
 
UDR was the tangential (up-down-rolled) surround Fostex developed for the ESigma range. For some unexplained reason they decided use it on the old FF85K; it was the only unit other than the ESigmas to have it, but its certainly effective and has some advantages in diffraction terms. Nothing massive, but it was a nice touch. The wk has moved ahead of its predecessor in terms of its cone design; likewise the spider & probably the VC too. But I preferred the dome dustcap of the old driver & the aforementioned front suspension. Overall, the wk is the superior driver though, so can't really complain. ;)

I don't much like foam either, but the more recent types are lasting a lot longer, so in general its less of an issue than it used to be.
 
Last edited:
Funny how a post about an unheard-of driver from SB acoustics gets pounded by (in this case) Vifa and Fostex! :p
It was just a heads up really, since I´m trying out some of the 3" full-range speakers available and bumped into this one. Looks cute though! :)

Having said that, I may just try it out just for fun, what is this hobby all about anyway right?
 
Last edited:
It depends on what you want the driver for. I've used the TG9 fibreglass cone and that really needed a tweeter to my ears, also it had problems with high distortion created by resonances beneath the dust cap. I largely solved these by removing the dustcap and installing a makeshift phase plug.

The TG9 and similar have a much larger cone area and swept displacement vs the little SB and need a bigger cabinet to work properly. In both my implementations I've used a DSP to apply a linkwitz transform and high pass to extend the useful range of the driver whilst limiting its excursion below frequencies that it cannot easily cope with.

The SB driver doesn't need any modification and definitely does not need a tweeter. It is probably the best driver of its size available today. Compared to other drivers of a similar chassis size it packs in more SD and considerably more xmax. The build quality is excellent (SB have a nice foam plug beneath the dustcap to stop resonances) and compared to other full range drivers, actually has an almost ruler flat frequency response.

The ribbed aluminium cone appears to do what you'd want it to, pushing the primary cone resonance up very high and it also appears to dampen the cone too as there are no sharp peaks in the distortion products at integer multiples below where the resonance occurs. This could also be due to the large voice coil, for a driver this size and the large dustcap.

If you've got younger ears and are going to miss that last bit of extension in the top octave then the SB will give you more than the TG9/TC9 series, but at the expense of some sensitivity and low end extension. As far as I am concerned though, if you need a driver of such small proportions then there's no contest, get the SB65, or if you need a small mid range driver, where the sensitivity is high enough, then get the SB65.

I really have nothing bad to say about it except for what the laws of physics prevent it from doing. The fact it doesn't cost much is just a very nice bonus.
 
I agree with 5th element as the SB65WBAC25-4 is a nice little driver that can be used for PC speakers, TV speakers, soundbars and portable devices. It has a nice tonal balance, likeable sound quality and lacks any nasties at the top end etc. Very honest in it's presentation when used within it's limits.

As a test, I tried it compared to a Samsung 7 Series TV speakers and a massive improvement.

I did a little PVC speaker with it.... Vb=1.4 litre, Fb=80Hz and gets below 70Hz. I added a RL contour network to help with a tad of BSC and with nearfield use. A chamfer on the inside of the driver hole is a must to allow free air flow. 6mm felt was used at selected locations inside the pipe elbow plus 30mm damping in the bottom.
 

Attachments

  • RZ2_PVC.jpg
    RZ2_PVC.jpg
    100.9 KB · Views: 384
  • RZ2_baffle.jpg
    RZ2_baffle.jpg
    86.5 KB · Views: 386
The MA crowd will tell you to use your ears, not look at the measured graphs. That's probably why there isn't a lot of data out there.

I have used the SB65 a lot lately and I agree with what's been said here. It's a wonderful mid range with almost the qualities of a tweeter on top. Very wide dispersion on top.

To use it to its full extent, you need to cross it at 300Hz at the lowest. Lower than that, distortion arises quickly. So, it needs a woofer for the lower end, not just a sub, as they don't go low enough (unless you are listening to them at very close range and very low volume).

Once dialled in, you will marvel at its resolution on stringed instruments. Guitars, violins, piano, etc... It's like they are playing right in front of you and you can almost feel the bow on the strings of the violin.

They do need a long break in period. Not the 500 hours of the MA drivers, but at least 100 to 200 hours. At first, they sound a little harsh, but open up beautifully after break in.
 
Thanks, it seems like the MA 5.2 will go lower, especially in a t-line, but the sb will be cleaner overall through the upper mids and treble, a bit like a high end PC speaker. Do you know if theres a dip around 1000 hz like the factory graph shows?
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.