(OT) Adding a ribbon tweeter to my speakers?

[voice of the theater]

Before the L-pad. The ribbon will likely have lower sensitivity than the CD/horn.

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.....

[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.

[voice of the theater]

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?

[voice of the theater]

I plan on keeping both sections of the 604 running not swapping the ribbon for the HF section of the 604.

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.....

[bowtie427ss]

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.

[bowtie427ss]

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.

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.

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.

[gearfreak]

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.)

[VolvoHeretic]

Go get two or four $3 piezos, hook one or two up to your main amp speaker wire with that capacitor, crossed over at 10000Hz, lay them on top of your speakers and see how they sound. like 'em or hate 'em, it's only $12 to experiment with, much cheaper than your open baffle. Move up the ladder from there if you don't like them. From what I understand, it's only harmonics up that high anyway.

[Steve Mac]

I put ribbon speakers above 10khz in my system and I've never looked back.
All of a sudden the sparkle is there and the wider spray is total ear candy.
But do it if and only if you got the midrange and mid bass right.
Which fortunately for us, Altecs shine at. Buy the good ones...

[Cal Weldon]

Hi cradeldorf,

I had just typed out a nice long response and the darn thing timed out on me so I am just going to give you the highlights.

I am glad OG popped in to straighten some things out.

1. Don't bother with the G1. It is too much of a tweeter for the job, you will be wasting it. The G2 is their entry level unit and is perfect for the job.

2. I have never heard a piezo tweeter that didn't sound like a piezo tweeter. Even when persons tell me how important the XO is, I try the same thing as them and it still sounds like **** to me. There's a reason they are so cheap. There's a reason I have a bunch just sitting on the shelf.

3. I think the 2.0 cap is too big. You will have too much overlap and that will distract you. If it were me I would start with a 1.0 and if that din't cut it, go to 1.5. That being said, it's easy when you have this stuff on hand but the nice thing is, when you are ordering it, you'll notice how cheap the smaller caps are. Get extras, you may want to add series resistance and that might mean running a couple caps in series. It's easier than doing the L-pad thing.