The Walnut Dipoles

Hello Friends need help I have the SB 15OB350 not the eminence woofer also I dont know the corossover how to make. If I use the SB woofer what change in crossover is needed. I really want to make this happen. Also if I use the crossover that Perry published with my SB what issues will I have

regards
anand
 
Moved into a townhouse. Dealing with thin walls got me interested in some dynamic driver dipoles. Figure worth a try to minimize annoying the neighbors with bass and make for a different (and thus fun for me) project. Have you done any work with an analog (active or passive) crossover on the input side to the amps?

Also, any investigations in using a similar rear-firing tweeter as the front firing? Given the reflective purpose of the rear, would matching voicing matter that much or provide any improvement?

-tom
 
I don’t think you need a midrange. If you do use a midrange, you should use a larger woofer, or two 15s.
Why you don't think a midrange is needed. If i want to avoid cone brakeup and match directivity i'm not sure i can avoid it.
That said, i'm not familiar with OB and i can imagine that what's true for conventional speaker may be different for OB.
By the way, you have used a 8" coax midrange in the "live edge dipôle" instead if simple compression or tweeter.
My idea was to make a kind of a mix between the live-edge the walnut (and bitches brew woofers)
 
  • Like
Reactions: perrymarshall
@perrymarshall: Perry, here’s a thought experiment for you 😉. Suppose you were starting with a clean sheet of paper and your aim was to design an OB speaker that was better than the BB, and lets also say you were not too constrained by the cost of the drivers. What combination of drivers might you pick?

Regarding the woofers, Peter Lyngdorf has said that the new 10” Purifi woofer is the lowest distortion driver ever produced and having heard some speakers that incorporate them I am fully prepared to believe it. I’ve seen the view expressed that the Purifi drivers do indeed have exceptional performance relative to their size, but that the same level of performance could be achieved by choosing a bigger driver. I do however wonder about that; when developing their studio monitors these guys tried out various woofers to go with the Blies-ma tweeters and mid-range that they had already settled on. None of ones they tried could match the quality of sound of the Blies-ma drivers, that is until they tried the 8” Purifi woofer. https://www.presentdayproduction.com/

The sensitivity of the Purifi 10” is quite low and I don’t like the idea of throwing away the presumed sensitivity of the tweeter / mid-range. Mitch Barnett mitigated that problem by using a lower gain amp on the tweeter of his 2 way active system. That seems like an elegant solution to me.

One last thought re the Purifi 10” and its a prediction; when Steinway Lyngdorf eventually upgrade / replace the Model B, I will be very surprised indeed if the woofers they choose are not Purifi ones . . .

Anyway Perry, next time you have some time to kill perhaps you might idle your time away by thinking about my thought experiment ?
 
2 10” Purifi and a T34 + WG in a “Flanagangster” configuration would work very well.
 
  • Like
Reactions: yoaudio and Studley
  • Like
Reactions: perrymarshall
I built a pair with the 150B30 and the Peerless by Tympany XT25-TG30-40 in a Wavecore waveguide.
I used Water Oak Slabs.
I also used xmachina to design the initial crossovers and finished up in Vituixcad.
I used Perry's bass boost circuit: the 680uF capacitor and 22 mH inductor.
The woofer is a bit more sensitive than the tweeter in the waveguide, so the 24 ohm resistor pads it down a bit.
They sound great. Very natural.

PXL_20240517_163408515.RAW-01.COVER.jpg
1730746984303.png