Hi Guys, I'm thinking
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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.)
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.
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...
3 dB is a doubling of power, not perceived...generally 3dB is accepted as the smallest noticeable increase..lots claim to hear better, but don't have controlled tests. Trained ears can obviously do better than untrained ones, so bear in mind the 3 db description doesn't apply, they are not the "average" listener, due to being outside the norm.
if you wanna use a crossover cap on peizos a parallel resistor is necessary, or an L-pad, so as to present an 8 ohm load to the xover. This would be in addition to a series resistor which is recommended.
Essentially a parallel set of peizos, with a 20 ohm series resistor, wired past an L-pad, is the simplest.
Trimming the flanges of the peizos so they couple better has merit.
The peizo has a "falling" impedance curve...40-50 Ohms, say, at 2K, falling to perhaps 8 at 40 KHz. This leads many ignorant marketers to claim no crossover needed, and the peizo's bad rep. They produce energy all the way down to 800 Hz or so, in a bad fashion. My opinion calls for 6-7 KHz or even higher usage. I use half a dozen stacked in a vertical array, with the flanges trimmed. Amazing how good they CAN sound when used properly, especially at the price.
Using piezo tweeters wisely: a "how to" - AudioKarma.org Home Audio Stereo Discussion Forums
Lynn and Steve's Piezo page
Do this-stack VERTICALLY. I like them closer together.
http://www.hostboard.com/forums/hbmc...2012/02/35.jpg
Horrible idea, do not do this! Comb filtering Hell.
http://www.hostboard.com/forums/hbmc...2012/02/36.jpg
Why a series resistor? 8 ohms at 40 K divided by 6...equals freaking out amplifier. Not many ruggedized pro amps will handle a load like that, much less home stuff.
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.
OK, if you have 500 to spend on used supertweeters then you'll have no trouble getting a handful of caps and resistors, maybe even some test leads to make the switching easy. Just get 1.5's and 1.0's as you can always parallel two 1.0's to get a 2.0.
Take your time. Switch, listen, switch, listen... I have been working on a simple set of FR drivers with helper woofers and helper tweeters and do you think I can make up my mind when trying to voice these things? As of last night I finally said OK, enough is enough, they're not going to get better by switching anymore. It only took 4 weeks. :)
You don't want it coming in at 5K unless you are cutting off the 604 horn at 5K. You have already said you're not quite an electronics professor yet so let's try and avoid doing that.
An XO calculator can only tell you what happens at a given impedance. You don't know what the real impedance is at the intended XO point so it's easier just to bring your tweeter in nice and high.
Then get a tweeter more suited to the job.
Consider making it 12dB and reverse the leads.
I can vouch for the Seleniums, sorta.Quote:
Originally Posted by Cal Weldon
I have some ST-320's, and like them a bunch. Sadly, they stopped making the ST-320 a few years ago. It's a facsimile/clone of JBL 2405. They do pop up on ebay from time to time.
I did an online hearing test and I could hear 12khz, but couldn't hear anything 14khz and over. My wife sure could. :(
JBL is now using the seleniums in some of their offerings....Quote:
Originally Posted by bowtie427ss
link to Audio heritage discussion...
when did jbl merge with selenium? see www.jblselenium.com
Cradledorf, First I would like to say that I haven't seen anybody have as much fun as you with your Altecs since I joined this board. Your not afraid of trying anything. It's inspirational. Second, a even cheaper Selenium to try is the ST-200. They're only twenty bucks a piece, and you might even have to turn them down running with 604's. I have three ST-350's for my three front channels and it's nice to hear highs again. But, if I could do it again I'd get the 200's. Less money. Keep experimenting !
A 2nd order high pass filter by nature of it's function inverts the absolute phase 180 degrees.Quote:
You lost me? why would I want to run them out of phase?
If you trace the wires on any properly wired high pass section in a 2nd order Altec network, you will see that the red wire(+ for the horn driver) is actually connected to the ground(- minus) side of the input.
Pretty doubtful that domes will be sensitive enough. The majority of them run in the very low 90db range while the average sensitivity of your 604's is going to be ~100db.Quote:
I bought that 3 set of Onkyo surround speakers and they have small dome tweeters in them that I could just pull out.
Could be tired phragms, weakened magnets, or even simply the midrange forward sonic character of the 604's themselves.Quote:
I wonder why the HF section of my 604's aren't doing it for me? 60 year old Phrams probably. : /
For me personally, if i were going to stick with a passive network on my 604's i'd have to strongly consider cloning the 604K network which has a MF adjustment that can be dialed back a bit. Sometimes taming the mids down a bit can increase perceived VHF output.
Do you have an EQ in system such that you can try pulling down the mids a few db in the XO frequency region?
Agreed.Quote:
Originally Posted by bowtie427ss
Was the H network the first to have both?Quote:
For me personally, if i were going to stick with a passive network on my 604's i'd have to strongly consider cloning the 604K network which has a MF adjustment that can be dialed back a bit. Sometimes taming the mids down a bit can increase perceived VHF output.
Sometimes you just have to if you're nearfield.Quote:
Do you have an EQ in system such that you can try pulling down the mids a few db in the XO frequency region?
Cheers.
Re Adding a ribbon tweeter
Then you would no longer be a genuine 604 listener, for what its worth I would get or borrow another newer 604 crossover, yours are aged and the caps are dried out & maybe leaky,do a comparison test using pink noise source & you'll hear a high end difference. GP has a HF horn mod, which might help and they also sell a new 604 crossovers,better than the type you have, main thing is it ALTEC. (Todd White should be able to advise)
That's funny. :)
Your video is blocked? Doesn't Don Henley have anything better to do with his spare time? Which cabs are you referring to--any pics?
Strange that the 12's are boomy considering the Q is going down as you get bigger.Quote:
Originally Posted by cradeldorf
If you want to reduce the size of the cabinet, you can always just add something to the interior to take away the volume, like bricks or wood pieces, as in a false wall or W.H.Y.
Great! Please let us know how they sound and keep us in the loop with some pics as well.....Quote:
Originally Posted by cradeldorf
I just watched some of your videos the one with the link sounds the best to me it seems.. thanks for sharing
Any pics yet?
as i represent slightly more than 16% of your current youtube subscriber base,Quote:
Originally Posted by cradeldorf
id like to request a video as well as pics.
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p.s.
i'd hope you'll play something like this, as it has tinkling cymbals and expensive guitars -
http://www.youtube.com/watch?v=E_C6XTuYfbU
Quote:
Originally Posted by cradeldorf
how about both?
together wouldn't be more than 10 minutes.
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( this one ? )
http://www.youtube.com/watch?v=UAOxCqSxRD0
or
Chris Isaak - Baby Did A Bad Bad Thing [Uncensored] - YouTube
i had no idea.
cheap cameras i use have SD cards,
so it only takes about 5 min.
12mega pixal for $25 -
Electronics Department Deals at Big Lots
Cool, they look cool!
* Tomt posted an interesting thought on the current 329 horn thread... hmmm. 329's would look cool on top of those as well!
Agreed--your 604's in those cabs with the new tweeters on top look awesome! Really looks like a serious set up! Looking forward to hearing how they sound with the new caps--sounds like your getting close to finding the right cap value(s).....
Technically, there is, vertically oriented to the outside of the driver, i.e. mirror imaged speakers, then toe them in as required to get the desired blend and to reduce reflections off of side walls towards the listening position.Quote:
Originally Posted by cradeldorf
GM
Cradeldorf, I finally listened to your videos, I like Pink Floyd and Led Zepplin the best. They sound like poor recordings playing through Altecs on my Altecs. :confused: I know nothing about your 604s, but all of the other Altec systems I have been looking at have something like a mere 33 or so sq. in. port opening, are you sure you have your boxes figured out right? Also, shouldn't the super tweeter's voice coils be more in line with those in you 604's?