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

[perceval]

It depends. On paper, the 5.2 may look like it can go lower, but there are no distortion data so it's hard to say. It may play lower in a T-Line, but sound horrible.

I have tested the SB65, and saw the distortion rise below 300Hz, so it was an easy call to match a woofer (or two!) and keep the little SB65 clean.

I did not see a dip at 1kHz, nor did member Byrtt.

Here are his and my measurements of the SB65, including distortion:

 

[33Polkhigh]

It depends. On paper, the 5.2 may look like it can go lower, but there are no distortion data so it's hard to say. It may play lower in a T-Line, but sound horrible.

I have tested the SB65, and saw the distortion rise below 300Hz, so it was an easy call to match a woofer (or two!) and keep the little SB65 clean.

I did not see a dip at 1kHz, nor did member Byrtt.

Here are his and my measurements of the SB65, including distortion:

Good information. The measurements at listening volume show distortion about -20 at fs. This looks like its not going to sound like a nice woofer but that level of distortion down low isn't a dumpster fire either.

I do see a bit of a sag moving to a peak around 2500 in some of graphs. Its more pronounced in the factory graph.

Its also in this measurement done by Feleppa.

http://www.feleppa.com.au/pics/speaker_imgs/plots/SB65_FreqResp.png

 

[perceval]

If you want absolute ruler flat, you'll have to use DSP.

Actually, I like a tiny hump at 2200-3000Hz, it brings out a lot of details in the songs.

Like I said, you are not going to bring this driver down to its Fs. There's so much you can ask a tiny woofer with very good resolution and dispersion up high.

In this case, you have to let another driver take care of the low end. Simple.

I consider the SB65 the Schwarzenegger of tweeters. It has the high end reach, and can be crossed between 300-500Hz.

 

[33Polkhigh]

After listening to these drivers for a little while I'm really impressed with them. One thing about them is they sound very good at low volume, better than anything else I've heard.

I posted in another thread that they might be able to be full range. I'm not sure about that. There seems to be a rise in the response around 250 and then it starts rolling off from there. This is more of an issue than the harmonic distortion down low.

Maybe someone who knows more than me will design a horn for them.

 

[xrk971]

It’s a great driver. Has more top end than if a TC9. There more in the other thread.

SB Acoustics SB65WBAC25-4 - What to do?

I would use it in a FAST rather than expecting it to do much below 150Hz.

 

[perceval]

What X said, crossed 350-500Hz, with a Harsch XO if going active.

 

[33Polkhigh]

Yea I'm blown away by the sb65's. The sound is solid and clean.

I'm scrapping another build to do a fast with these using this woofer.

Dayton Audio RS150P-4A 6" Reference Paper Woofer 4 Ohm It has a great midbass and transparent sound.

I think a 500hz 12 db/octave active crossover should be good. They will be close enough that they are within 1/4 wavelength till about 1000 hz. So it will be a true point source.

iirc when you are within 1/4 wavelength the drivers need to cross at the -6 db point to sum flat.