How to Train Your PM180-8

[scottvalentin]

This was a fun read - hadn't seen it before. jbruner thanks for updating this.

[jbruner]

Glad you enjoyed it. I aim to please.

[Pete Basel]

It would be great if someone could make a 3D printed template with slots to guide the cutting
of this cone. Then anyone, hopefully, could make the slit cone version with at least some
confidence.

[scottq]

They have been Ryan's main speakers since the day we finished them. Still occupy his main listening room today. Your mod is utterly transformative and should be incorporated at the factory.

That's some impressive feedback and praise!
Thanks to jbruner for the update

[scottq]

It would be great if someone could make a 3D printed template with slots to guide the cutting
of this cone. Then anyone, hopefully, could make the slit cone version with at least some
confidence.

I'd be willing to take a stab at it - sounds fun. Send me a PM if you're serious.
Is the PM180 seems to be NLA. I suppose could do it to the PS180 instead - hack the whizzer off first.

I don't personally have any of these drivers, so would need some measurements provided.
This PM180/PS180 cones appear to be quite conic in the pics? Are they as straight in reality as they appear?

Frankly, I'd be interested in making this mods to a lot of drivers...

[tktran]

Yes, what about the SBA paper cone. They are a paper cone with a horrible breakup 5-10KHz.

What did I miss? Sensei, what's the glue that's used and show me how?

[jbruner]

Yes, what about the SBA paper cone. They are a paper cone with a horrible breakup 5-10KHz.

What did I miss? Sensei, what's the glue that's used and show me how?

I did a shootout with the sliced SB15 vs the Revelator.. This thread "Scan-Speek 4" for 49 cents?" started it all and explains everything. All of my modified drivers so far include pole cavity treatments under the dustcap. The glue is DAP Alex plus clear. More discussion in this DIY Audio thread.

[tktran]

Loves the part about

"The Scan settles right in, making you think you are a good speaker designer. This is why you spent the big bucks, right?"

LOL!

So what were your conclusions or progess on that 2 years later. Did you continue to modify any others or move forward with the SB? Or did you go in a different direction?

I'm convinced smooth off axis matters, way beyond the pass band. It's probably why paper-type cones are preferred to metal cones. Maybe. Or maybe not. I don't have the evidence for that. Apart from the fact that virtually call P/A / pro drivers do NOT use metal cones

[jbruner]

Sliced paper is definitely the right thing for midrange performance. One reason smooth off-axis is so important, is that when the anomalies are from break-up, the crossover correction on-axis just makes the off-axis even worse because it's at a different frequency. So, I wouldn't really say it's the off-axis as much as the break-up itself. You have to get rid of it. The Scan revelator showed us the way, but modern motors have gotten better since then, which is one reason the modified SB15 won the comparison. My slicing technique seems to be more effective than the rev, due to softer glue and a narrower slit. Kapton formers are audible, too. I wasn't completely happy with the original SB15, but I'm thinking the new version SB15NRX2C30-8 with the straight cone will be a better candidate. I'll update that thread soon, so we can move this conversation over there.