Curt Campbell's Halcyon build thread

6sX7

Member
2018-04-30 5:08 am
Given the accuracy (lack of), how much of a shelf?

I'm wondering if that was some of the shoutiness I experienced. But then, it seems to have resolved itself going to balanced mode in the 1stWatt Clone F6s I built. So the chain of reasoning isn't quite there. Guessing it was more of a distortion product.

Have you pulled the main chamber stuffing to see how it affects the sound?

Now that I've found I have plenty of gain with the Benchmark DAC3, I'm considering building a set of balanced F4s. It'd cut the output impedance by a little over half compared to the F6s and many diyers that have built them say the circuit is as neutral as they've heard (cathode follower).

Not sure when but next steps for the Halcyons are to pull the x-overs, upgrade them and mount externally. After that, can try some active x-over stuff.
 
So after a few weeks of daily listening and a few rough measurements, I have decided to explore padding down the A10P at least 2 dB to compensate for the difference in lower efficiency of the SB SB17NRX2C35-8 woofers. I am asking the experts here what the bestway would be to accomplish this with the existing crossover.

Curt Campbell suggests changing the resistor R2021 to a lower value to make the balance change the other direction. Will adjusting the resistor higher in value, or a parallel resistor across the drivers be the better approach, or is there a much better way. I have read suggestions on the forum and other places for both ways. I would appreciate your thoughts.
 
I was surprised that there were not more replies to my question. I am an BSEE with many years of design experience in audio processing hardware. But my speaker building is limited. I was hoping for a few more clues as to how some of the experts out there would approach this. I can certainily simulate and calculate the crossover components accurately.

What has worked best when confronted with a change in efficiency in a driver such as this?

6sX7, I gave up trying to find the original woofers. I think that Madisound ran out of then just before I ordered my set. I haven't had time to work on this the past few days, but will soon. I will post what I learn.

-david BTW
 

6sX7

Member
2018-04-30 5:08 am
I was surprised that there were not more replies to my question. I am an BSEE with many years of design experience in audio processing hardware. But my speaker building is limited. I was hoping for a few more clues as to how some of the experts out there would approach this. I can certainily simulate and calculate the crossover components accurately.

What has worked best when confronted with a change in efficiency in a driver such as this?

6sX7, I gave up trying to find the original woofers. I think that Madisound ran out of then just before I ordered my set. I haven't had time to work on this the past few days, but will soon. I will post what I learn.

-david BTW
I've noticed this thread is not the most trafficked. I've appreciated those that have stopped in to offer any help/advice.

Given the original woofers aren't available, I've thought about revisiting the design all together just need to start working the test equipment and experience. Hence the previous post about going to an active x-over. I very much like the MA Alpairs as they fit the bill for a "point source" with performance going up a notch when unloading the bass off of them. Definitely the direction I want to stick with, just need to find some in-production woofers to match them with.

I will keep an eye on this thread as I'm interested in what you learn. Will post on whatever my experiments get off to as I finally have the resources to build up a testing capability and try some real x-over design. Just need to get these F4 clones built so I have my reference system to work with.