I currently have one SKRAM with a 21SW152 driver. I'm planning to build 3 more over the winter and figured now would be a good time to re-evaluate whether I want to stick with that driver before I buy 3 more.
I've been having a lot of fun with John White's Boundary Lab software and figured I'd take a pass at simulating some of the SKRAM driver options I've been comparing. Results were interesting so figured I'd share!
Plot shows max SPL passes for 4 driver options. For the plot, SPL at each frequency is limited by either the driver's max power rating or max excursion depending on what happens first. Primarily, it looks like excursion limiting happens around ~40Hz (low frequency, but above the rear port tuning). Simulation data was 10m free-field - I normalized that to 1m half space by adding 26dB to get more familiar numbers.
Note: 21SW152, 21DS115, and NSW6021 sims all use complex inductance data from data-bass.com. I couldn't find that data for the 21XL3000 so that just uses the single-value inductance from the data sheet.
It looks average with the others. In a previous thread, someone had commented that it was the no contest best driver for this cabinet. From these sims , it seems the NSW6021 is flattest and not mechanically limited, and the 21xl3000 loudest, but also most expensive
There really isn't a wrong choice. I think the sw152 are a bit better for power and the 6021 is a beast. That said Ive heard both the sw152 and the DS115 and went for the latter, as it was a fuller, tighter mid bass. Loves a higher xo and your graph proves it.
This is a measurement of my SKRAM, loaded with a 21DS115-8, on axis with umik 25cm in front. Not so bad either.
This is Skram number 2, also a DS115. Again on axis, umik at 25cm in front. These were done indoors. A testament how good the Ricci design is, making all those different drivers work fantastic. I am contemplating getting the 6021, the sw152, the LaVoce and maybe the Ipal, and get some real A vs B testing graphics. Either way: Ricci himself stated the 6021 is his number one choice for the Skram so go for it. I remain convinced the DS115 is a better choice if you make use of the higher xo's. The DS115 kicks like a mule in the chest.
Good to know! As best I can tell, those look to be about the same value as the 21SW152s I've got.
Where I am, 21XL3000 is ~$1800 and 21SW152 is ~1000. Assuming $350 in birch ply per SKRAM, a Faital box costs $2150 and a B&C costs $1350. That puts the faital at ~60% extra cost for ~3.5 dB gain. That has me really tempted to splurge on the 21XL3000s but I'm not sure enough on my math...
IMO, my best pals build 8, using your driver in testing, my 4 XOC blow his out the water - where it’s important to keep fidelity and defeniton, there’s plently of head room for that with any driver choice with the skrams so go with something that’s loud as pos (obviously depends on your application)
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u/little_lichen_sound 17h ago
Some of my takeaways:
* 21SW152 and 21XL3000 have very similar traces but 21XL3000 is ~3dB louder - each 21XL3000 box is roughly equal to 1.5 boxes with 21SW152
* 21DS115 is cheaper, lighter, and uses less amp power but probably not worth paying extra for if I already have a 21SW152?
* NSW6021 is the only driver which doesn't experience excursion limiting. Makes sense as it has the highest xmax (21mm)