Hi Guys, I'm thinking
Printable View
Hi Guys, I'm thinking
I would say to the HF side of the crossover... BUT, what's the Frequency Kenneth? ;)Quote:
Originally Posted by cradeldorf
I think that an appropriate xover point and slope are going to be important,
if you would like to keep the ribbons going strong, longterm...
depending on the crossover you have in place now, you may be able to adjust it -- or you may need to make some additional -- more invasive -- adjustments... or....
maybe running the ribbon in parrell with your HF driver;
with an additional capacitor inline to provide a 6db/oct filter, would do it....
(although I have no experience with them, my understanding is that the ribbons are somewhat fragile --
so I would suggest limiting low frequency energy to what is appropriate for the driver.....)
I am sure more knowledgable folks will chime in... lol
Before the L-pad. The ribbon will likely have lower sensitivity than the CD/horn.Quote:
maybe running the ribbon in parrell with your HF driver;
with an additional capacitor inline to provide a 6db/oct filter, would do it....
Cradle, post some specs or the model of your ribbons so folks can give more concise responses.
If I remember correctly, the GPA crossovers he's using for his 604's don't have L-pads.....Quote:
Originally Posted by bowtie427ss
There must still be a fixed pad of some type, no? as the 604 HF and LF sections don't have the same sensitivity.
Good point--there must be something in place to "tame" the higher efficiency of the horn as compared to the woofer.... Cradeldorf--do you have a schematic of your crossovers?Quote:
Originally Posted by bowtie427ss
Sounds like a good plan to me. That way you don't lose that classic 604 sound--you're just enhancing it's high end response (with the tweeters added, the h.f. will roll off way past where you'll be able to hear it). Not to mention, the woofer in your 604 will never play all the way up to the ribbon tweeter--you'll need the horn to go down to 1600 hz.....Quote:
Originally Posted by cradeldorf
I question R1 being parallel in the woofer circuit. I think it should be across the HF circuit. If that's the case, then that series/parallel resistor arrangement of R1 and R2 would be your fixed pad simulating an L-pad "locked" in one specific position. But i'm not familiar with this network so can't say for sure.
My advice with a ribbon as delicate and valuable as the Aurum would be to bring it in up high, maybe 8khz to 10khz with a simple first order(single cap in series) XO. I'm assuming that you're looking to fill in that "sparkle" in the top octaves, and i think this arrangement could go a long way in doing that.
The problem with just going off the HF taps on the XO is that signal has been attenuated to match the LF driver's sensitivity.Quote:
Using an online calculator for an 8 ohm speaker and I set the hz at 10Khz it says I need a cap that is 2.0 microfarads. So are you saying I should just hook that to where the HF leads come off the crossover? or are you saying that It needs to be plugged into the middle of the crossover somewhere? Or before the crossover?
I got a line on a pair of used Arum Cantu G1's They look and sound much more like what I should use. I'm probably gonna jump on them.
In the name of simplicity and keeping your XO's unaltered i'd probably just opt for tying in before the XO.
2.0 uF in series with the + sounds like a good starting point to me.
In terms of sensitivity, the G1 is probably going to be the better match. However, it is sensitive enough that it takes us a couple db past ideal and could actually need an L-pad to be able to back it off slightly when you get to final tweaking, or depending on how many db the XO attenuates the HF you might end up tying in at the HF taps after all.
The Aurums are really nice ribbons. You'll find them used in several high end/expensive systems. Be careful with them. None of us want to read about a broken one.
I think starting with 'what's the output of my 604's HF' is a better place to start.
Remember (or know), +3db = a doubleing of perceived volume (guys correct me if the terminology is not accurate).
So the 92db rated beston, is going to be half as loud at least as the 96db AC you initially post about. That's a big difference imo.
If the bestons are still viable, then they look cheap enough to play with. Otherwise investigate non-ribbons for other cheap options. Beyma CP09 (discon) /CP25 (more $), Piezo array...
Maybe instead, start with matching the new purchase's output (check the FR curve, make sure it's in the area you plan to use!) to that of the woofer, then just pad back the 604's horn accordingly (kind of a continuation of bowties suggestion).
For the 604 woofer section, you should be able to get nominally correct values, from it's companion. e.g. If a 604-k or l, probably matches the 515-8g series? So check the 515-8g for output spec'd in an alignment similar to yours (on horn in A7, or simple BR box, etc.)