Doug's Dipole Project

**ThomasW** · 28 March 2005, 16:31 Monday

Do the 4" mids have enough output in a dipole config?

**JonMarsh** · 28 March 2005, 16:49 Monday

Hello Doug,

Glad you're having an entertaining time messing around with some inexpensive drivers to get your feet wet with dipoles! It would be hard to imagine you doing it for any less money....

OTOH, those buyout special 12's from PE only have 3.5 mm Xmax, so I would be careful about using much EQ on them to get the bottom end in shape. Monte Kay put together a dipole system using the RS270 Daytons, and with 10's and their 7 mm Xmax, was running out of gas on the bottem end pretty quickly, too.

Do you have a modern copy of Excel on your PC? You might find working with Baffle Diffraction Simulator from the FRD consortium (free download if you haven't heard of it yet) on the driver layout- baffle loading in the midrange for a dipole is dependent in some ways in the same way as for a sealed box, and symmetrical layouts don't produce the smoothest frequency response.

I'd take a pass at something similar to Davey's driver complement if you're looking to keep the bucks down but raise the performance level a bit. Regardless, have fun and let us know how things turn out.

~Jon

**Doug Lockwood** · 28 March 2005, 20:32 Monday

Do the 4" mids have enough output in a dipole config?

As long as I keep the crossover close to Feq, the NSB's play as loud as I want to listen

.
The speaker is on a 47.5 Cm baffle, so Feq is about 240 Hz.

It would be hard to imagine you doing it for any less money....

LOL.

You might find working with Baffle Diffraction Simulator from the FRD consortium

Thanks, I'll play with it. The speakers are off center by 3/4" or so, but it was Kentucky windage.

OTOH, those buyout special 12's from PE only have 3.5 mm Xmax,

I was aware of that, but it hasn't yet been an issue. It may be the distortion in the drivers makes them sound louder than they really are.

Regardless, have fun and let us know how things turn out.

Thanks. My goal is to have the real ones built before DIY Chicago. I'll keep you posted.

**cjd** · 28 March 2005, 21:04 Monday

The NSB's are interesting drivers. They're nearly indestructable (I've tried) and if you cross below 4000Hz (I use 3800 and 3200 depending on the speaker) sound amazingly sweet. And they're good open baffle - I have a pair I use as computer monitors.

They're not crossable on the bottom passively with any reasonable cost (800uF cap anyone?!)

Doug, what's your timeline? I'm embarking on an open baffle project one of these days and at the moment, my driver choice is:

Unknown for sure drivers up to ~50Hz(?) - 12's may work. 15's otherwise, probably. Maybe 18's. Very much unknown at this point how I'll cover the really low bass. But I want something I can toss in an IB or sealed box if I need to. I don't know if 16Hz open baffle is reasonable but I'm gonna try.

Next up is RS225's. From there I think it'll be Neo8's. And from ~5k on up, probably a Fountek ribbon.

I have this bad feeling I'm going to need four of the RS225's per side.

Since it sounds like you're in the area, I'd be happy to help out if I can on your project.

C

**Doug Lockwood** · 28 March 2005, 22:38 Monday

The NSB's are interesting drivers. They're nearly indestructable (I've tried) and if you cross below 4000Hz (I use 3800 and 3200 depending on the speaker) sound amazingly sweet. And they're good open baffle - I have a pair I use as computer monitors.

I remember hearing those; Pretty amazing for what they are.
Thanks for the offer. I may take you up on that. Sounds like we have similar tastes.

Doug

**Doug Lockwood** · 17 October 2005, 21:07 Monday

I entered these in the Mid class at DIY Chicago.
I got a very positive response, and we demo’ed several sets of Carl’s cables as well.

On to the next level. I have my test baffle for the RS270 / SEAS MP14RLY/P / B&G NEO3 (not PDR)(without back cup).
I'll check in with progress.

Comments and suggestions welcome.

Doug