SB Acoustics SB20FRPC30-8 (8" Fullrange Cheap Monster II)

I’m thinking of building an OB line array with these SB20FRPC30-8 drivers. It would be my first attempt at a line array. Should I do it?

I know comb filtering can be a problem. Should I use a single tweeter in the middle of the array?

I was also thinking about blending from a single fullrange unit at high frequencies to a full array below the c-c wavelength. Has anyone ever done something like that? Instead of power tapering, high-frequency tapering?

Or with the driver’s rising on-axis response above 3k maybe comb filtering won’t be a big deal?
Not a good idea…..combing will start around 800hz and you’d need massive EQ and the off axis response would still be awful. The purity of the fullrange solution is a single point source within a 3D space which creates a startling soundstage……if that’s what you’re after (most people are) use it as intended with help from (sub) woofer if higher output is needed.
 
  • Like
Reactions: perceval
I’m thinking of building an OB line array with these SB20FRPC30-8 drivers. It would be my first attempt at a line array. Should I do it?
I'm always up to try new things, but a line array of 8" FR drivers is not and it is doomed to fail miserably.

Read the white papers on line arrays. If you do want to do one, max size should be 3" drivers and will need heavy EQ.

Unless you want to do a bass line array. Now, that's something that is worth pursuing. I'd love to do a nine 8" bass drivers (to keep Ohms the same as a single driver) on each side, flanking the SB20, for example.
 
I was thinking of wiring it like the middle diagram here, so only one driver would actually be playing fullrange: http://www.planet10-hifi.com/downloads/Quad-Driver-Wiring.pdf
Meh... so, you'd like to use one FR doing wide band, and three more of the same FR driver doing only woofer duty?
Other than having visually a line of similar drivers, I don't see the advantages over using a dedicated mid woofers instead of the FR.

As Mayhem pointed out, your other three drivers will have to be low passed before 800Hz, otherwise you will enter comb filtering range. That's a lot of wasted energy.

Wanna use two? This driver sims very well in a MLTL. Put one in a folded line, XO around 300-400Hz, put the other on top going from XO point and up.
You'll have the line covering down to about 35Hz, and a very clean distortion free top driver, not having to handle the wider lower spectrum.
 
Hi all
another look on the measurements i did....
here in same scale of the axis as the manufaktorer data / specs.
Difference im method: SB in lab contitions ca 31cm distance, my measurement home, 1m distance in an enclosure
Enjoy..
 

Attachments

  • 8in-SB20FRPC30-8-drawing-1000.jpg
    8in-SB20FRPC30-8-drawing-1000.jpg
    109.7 KB · Views: 316
  • SB-8-FR-wie-Datenblatt.jpg
    SB-8-FR-wie-Datenblatt.jpg
    125.3 KB · Views: 303
  • Like
Reactions: lasercut
It is nice to see good data without photoshop directly from the manufacturer...🙂

Very nice correlation between measurements, you have diffraction bumps and baffle step loss, otherwise everything is the same....

Fun fact:

Satori MW16P is actually one of the best fullrangers on Earth, just nobody calls it that way....🙂
 

Attachments

  • SATORI-MW16P-8-freq.jpg
    SATORI-MW16P-8-freq.jpg
    73.7 KB · Views: 326
If somebody can, it would be nice to do FR measurement with whizzer cone slightly damped with piece od damping fiberglass or cotton or wool.

Just to stuck small quantitiy of damping all around between whizzer and main cone....5 minutes of job and it is reversible...🙂

I would measure but my boxes are still not finished......
 
Fun fact:

Satori MW16P is actually one of the best fullrangers on Earth, just nobody calls it that way....🙂
Thanks for that. I'm always on the lookout for a nice driver to put in my favorite design, MLTL. That one sims very well in a very tight package.
Myself, I would probably cross it at around 3kHz.

Not cheap, but looks really good. I'm sure it sounds just as good as it looks!
 
Dear nandappe.

Thank you for your kind reply. As you inspired me to try the SB20FRPC30-8, I just wanted to share my experience.

Yes, you are probably fully correct in regards to the 40+ year old Beta8 drivers. I listened to them for some time, as I got the cabinets completed.
And the sound was very crisp nuanced throughout most of the spectrum. The driver is sensitive to off-axis listening; especially for the high frequency. The bass range was clearly improved by the cabinet; and it has been capable of playing quit loudly continuously for several hours.
But as described; distortion have now been identified at specific midtone ranges.

As I was looking for a new driver; I was recommended the drivers from Tang; Tang Band W8-2145 (150€) and the W8-1808 (300€) - but both drivers are to deep for the cabinet. And far too expensive for my current budget,
Then I checked Dayton Audio PS220-8 (200€) - which seems perfect for the job; also with a very nice finish.
And finally I checked Markaudio Alpair-12P (140€) - without finding any projects or reviews.

As I have had very good experiences with drivers from SB Acoustics, I decided to give the SB20FRPC30-8 driver a try, after reading about your project above.

The SB20FRPC30-8 driver is far cheaper than the above ones. But therefore also tempting to purchase; just for experimenting.
And I must say I'm quite surprised how well it performs. Above price as you stated; I completely agree.
It can perform at very loud levels too; with out any distortion at all. The bass range is still acceptable; and the of-axis listening is much better than the Beta8.
So no complaints until now.

I should like to try with the more narrower cabinet that you have posted here. It looks very nice and quite elegant, due to the narrow front.

I very much appreciate good sound and good loudspeakers - but I don't have a professional ear - nor am I comfortable with the engineering terms to describe the sound and listening experience. Just an amateur.
What enclosure did u make I have the sb drivers looking for box dimensions for 2 versions compact sealed and another box as much as bass as possible
For sealed box if giving less bass I will plan to use Open Baffel subs
 
I have seen a few comparisons with other full range drivers in this thread. This may be an apples and oranges comparison, but what would people chose between the Alpair 10m the SB acoustics? I want to try a full range driver, and there is an appeal to both of these divers. Any opinions, or can someone try to explain the differences?
 
I have seen a few comparisons with other full range drivers in this thread. This may be an apples and oranges comparison, but what would people chose between the Alpair 10m the SB acoustics? I want to try a full range driver, and there is an appeal to both of these divers. Any opinions, or can someone try to explain the differences?
try both so good so cheap..I vote x sb
 
I have seen a few comparisons with other full range drivers in this thread. This may be an apples and oranges comparison, but what would people chose between the Alpair 10m the SB acoustics? I want to try a full range driver, and there is an appeal to both of these divers. Any opinions, or can someone try to explain the differences?
Based on reviews and better efficiency of 92db vs 87db I’d go for the SB without hesitation but if your amp is powerful (not a small SET low power one) you could also try the 10M.

I’m biased since I prefer bigger full range drivers for;

-Dynamics
-Effortless presentation
-Full bodied

Eric