chops

I didn't know that was do-able. So if you had a 1.4" or 2" driver, you could mount that up to a 1" throat horn? What would that do to the sound? Just curious. [] Charles

"Ah, Bellamy, for cryin' out loud. That's the the stinking, most awful, stupid joke and you're always pullin' that stinking awful stupid joke. You don't want in this thing, you don't get in this thing. I cut you in on everything. I don't need you. Sixty feet of bridge I can get almost anywhere. Schmuck!"

And here's the pics... This first pic is of the modified Type B, which is considered a Type CS II network Now converted to a 2-way. I don't know what it would be called now... Type AC (AlCorn) maybe? Tap #2 connection... Tap #2 connection, just a different angle with a little dust and cat-fuzz... Comparison of the 902 vs K-55... This one I purposely boosted the contrast to help show what's inside the driver. Is that the "tangerine" phase plug everyone keeps referring to? Driver for left channel mounted to 511B horn. As you can see in the background, Lil' Sammie approves!.... Naturally! Right channel complete and powered up...

The 902s just came in! Well, actually, they got here an hour ago, at 4:00 EST. After breezing through the first page of this thread again, making the appropriate changes to the networks, removing the K55's and adapters, and mounting the 902 drivers, 45 minutes later I have Altec 902-8B drivers projecting sound into my room. Once I had the first one completed, I went ahead and powered up the system. I played a minute or so of music just to see how close the K55 on tap #3 was to the 902 on tap #2. I have to admit, they were an almost identical match in output. Of course, this the first time ever for tap #2 to be used, plus there's no telling how long these 902s have been sitting, so it probably wouldn't be fair to pass any judgement yet on the sound. Not to mention that I'm listening to Pipe Dreams through them off of the interent which eventhough it is a good recording, it's definately not CD quality. I will say this though, these 902s seem to be a little rolled off on the top end, almost too much. However, I will play some various recordings through them for a while and see if they open up anymore or not. If they don't, I'll be going back to a 3-way, which will most likely be the case. I'll post a few pics in a few. I just said the word "few" a few times in a row! LOL []

Edit...

LOL... I can imagine. Just think what Bob's, Dean's and Al's collection must look like. [] At one point when I was younger, I probably had somewhere around 20-30 raw drivers just laying all over the place; in the corners of my bedroom, in the closet, under my bed, on shelves out in the garage (which there are still three 15" Pyle Pro drivers out there), some in the hallway closet, and I think I still might have a few hiding in one of my brothers closets! LOL

Are we talking about a b series network or AA network. I can post a pic to help clarify. I think you will find that the 68uf cap is not an in-line cap, but rather a shunt one. Meaning it does not establish the cutoff of the k-33, just the roll off. The roll of is the level reduction of adjacent higher octaves in the case of a woofer. The crossover point for the k-33 is established by an interaction of the in line inductor of the k-33 and the in-line cap for the horn. if you want to change the crossover point for your woofer and horn, both the in-line woofer inductor and in-line horn capacitor would have to change. the rolloff for each is effected by the shunt devices across the driver terminals....rolloff for woofer is controlled by a capacitor across the woofer terminals...rolloff for the horn is controlled by an inductor across the horn driver terminals. The shunt componets are located on the xover board. you should use a crossover calculator to establish the values needed for your in-line componets of your xover. I'm working off of a modified Type B network. As for the 68uF cap being a "shunt" or whatever, all I know is that when Bob was doing some testing on different value caps for the K33 for his Cornscala IIs, he first tried a 100uF cap and he said that the K33 started rolling off in the 300ish Hz range, which was obvioulsy too low. When he tried the 68uF cap, the K33 rolled off around 437Hz. Since the 2.5mH inductor never changed, then I automatically assumed the cap was making the final decision on the crossover point. Or maybe because the K33's 1mH VC and the 2.5mH inductor makes it a -12dB slope, then adding the 100uF or 68uF cap makes it a -18dB slope. Now please keep in mind, I am in the early stages of learning all of this crossover stuff, so most of what I know is only from what others tell me or from what I have read in other threads. I still don't know how what does that to who, and where it is when it does it, and why. I have tried the different crossover calculators before, but they are no good. As Al K has pointed out to me, those calculators ONLY assume a static driver impedance. They do not consider the VC inductance nor do they consider the impedance swings throughout the frequency range, so the component values are not correct. This has been proven the case several times while I have tried to model the simple Cornwall driver/Type B network combo (4 ohm woofer, 16 ohm midrange, 8 ohm tweeter / XO points of 600Hz and 6000Hz). If those calculators worked properly, I would at least get something close to the 2.5mH inductor on the woofer, 2uF and 4uF caps on the squawker and tweeter. But these calculators never come close to those values. Unfortunately, I don't have the luxury of spending $50-100 on crossover parts every couple of weeks to do experimental work on crossovers and end up with a bunch of wrong parts because those calculators told me the wrong values. That's why I am asking so many questions and wanting to do proven mods so I can get where I need to be. That way, I can be up and running ASAP and get all the bugs worked out before taking the plunge of building a pair for myself with all new and better parts. As much as I'd love to do all of this on my own, I can't. I'd much rather leave all the guess work up to the ones who know what they're doing. And trust me guys, all of your input is greatly, greatly appreciated! []

Duke, If possible, do you think you could elaborate on your post a little? I kind of at a loss here on what you are saying. Are you referring to the 511B horn being able to properly load a driver well below 500Hz? If I remember correctly, I was reading something on the Altec User Board a while back where someone stated that they successfully had their 511B and driver (can't remember if it was a 902 or not) playing down to 265Hz or 365Hz without distorsion. It was something like that.

Say if I get the 902 down to 500Hz, and the K33 up to 500Hz, what cap values would I need? I have that 68uF cap on the K33 right now which gets me 437Hz, so would say a 50uF get me closer to 500Hz?

Man, I just got done reading this thread from beginning to end. http://forums.klipsch.com/forums/1/514028/ShowThread.aspx Now you want me to read another one?! LOL Nah, seriously, I enjoy reading this stuff. Unfortunately though, you guys start getting a little too technical and I get a little lost in all of it. But still, it's all helpful and I pick up a little bit here and there. And just to clear up a little bit about my listening habbits. On a realistic level, I would say 90% of the time, I listen to my stereo at "normal" levels, probably somewhere between 70-85dB. Only when I'm listening to a particular CD or song that I really like, or if I'm watching a really good, action packed movie, do I have the system playing near or slightly above 100dB. I'm not as crazy as some. [] If I can get away with a lower slope rate and still be safe on the 902, then that's fine. I just don't want to blow the darn things. I was thinking also, if I was to bump the crossover freq back up a little on the 902, and since if I will have the entire tweeter section disconnected, AND if I do use the tweeter again but at a higher crossover freq as well, that means I would have at least one spare 2uF cap from the tweeter section. So with that in mind, and the fact that the current 7uF cap bank for the midrange gives me 375Hz, and the stock 4uF gives me 600Hz, then what would 5uF and 6uF give me? I feel the same away about what you said in your next post about letting the 902 play as wide a range as possible. That's what I'm trying to get to, but without running the risk of damage to the driver.

Hi jc, Boy, and people think I'm weird for liking the smell of gas... gasoline that is. LOL Anyway, like I just mentioned above, I am staying on the current course of action as Dean suggested. About the tweeter at 4500, I may end up not using it at all depending on how I like the 902 flat out on the 511B horn. If it gives me enough extension, or at least more extension that my old alnico K77s, then I might be happy without a tweeter altogether. Only time will tell. However, if I am not totally satisfied with the extension of the 902, I will want to pass the CT125 as high as possible just so I can get the most out of the 902. Maybe 8 or 10kHz? Charels

Chopsy ..... I think you will find the high roll -off x-overs work best on speakers with multiple overlapping drivers although , i admit, say a 12/dB/oct on a k-33, and say, a 2nd order filter on a 902/908 set lower than one would normally choose..... might improve power handling at what levels do you commonly listen ..?? i'd say, tho ... i suspect you won't need much power handling in the 902,with say, an 600-800 hz x-overed K-33 therefore, no need for higher order x-over and .... a 12/dB/oct ... may sound more open, and musical in a 2-way a lot will depend on the horn you choose, eh ....??? Dukey.... I'm using the Altec 511B horn, and my current crossover point is 375Hz on the K-55V driver. I do not want to run the K-33 any higher than where it's at now, which is about 437Hz according to BEC. If I could somehow get the 902 driver right at 400Hz with something more substantail than a 1st, 2nd or 3rd order network, then I think I'll be fine. That's why I would like something like -36 or -48dB per octave. And if I could integrate constant impedence into it, all the better. Granted, I don't play my system as loud as Terry does (IB Slammin) at 110-115dB, but I'm not too far behind him either at about a constant 100dB with peaks anywhere between 103-107dB. Chops Dean, Am I right in assuming that adding a Mills 10 ohm / 12 watt resister across taps #0 & 5 will pretty much make the network a constant impedence design like you and Al keep mentioning about? http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=005-10 Thanks

That would be these two... Quick Sweep: Pink Noise:

Don't worry Dean. I was referring more towards later courses. I plan on doing what we spoke about. And I do want to try some different caps, it's just hard tyring to figure which ones are the best for my application, (5% or 10%, Solen, Kimber, Hovland, Mundorf, etc, etc). There are too many choices and I'm obviously not up to full speed yet on what's what and why. If I ever completely figure out the whole idea of building crossovers, I would like to evenually have a 2-way (most likely - hopefully) network with a -48dB per octave slope on the Altec 902 at least, if not the K33 also. No brainwashing going on here! [8-|]

Hey Terry! I was wondering if you were ever going to add anything to this post. We 511B/902 guys need to stick together. LOL Ah, so jc is the one behind the Alcorn networks you were "beating around the bush" about, huh? Interesting. Yeah, I guess I'll have to drop him a line and see what he has to say. Every little bit of info helps. Thanks! Charles

Well DrWho, here's a few pics of mic placement... 1 Meter: 1 Meter: Listening Position @ seated ear level: And here's the two most important plots you were asking for... Cornwall Fullrange - 1 Meter - Quick Sweep - HiRes: Sub Only - 1 Meter - HiRes: This is the same Sub plot as above, but displayed all the way up to 20kHz: If you want to view ALL of the plots taken yesterday and today, go to my website and check them all out. The ones from today start with the last thumbnail on the second row, named "Fullrange Pink Noise - Sub". Here's the link to the page. Be sure to scroll all the way down to get to the second gallery... http://chops.tzo.com/subproject.htm

LOL... I'll say they are! [] Yeah, I think it would be pretty neat to have a couple of fellow Klipsch owners over for a visit. We'll have to do that one of these days! []

Gee.... picky picky... LOL Just to let you know, I'm in the process of running a few more plots at higher resolutions. The noisefloor in generally between 40-50dB, so I doubt that was messing with the measurements. The thing that's confusing me right now is the subwoofer plot with pink noise by itself. I'm not going to say anymore about it right now though until I do a couple more measurements. However, I might also have a theory about what's going on with it. We'll see in a few. As for adding the sub into the mix, all of those tests with both Cornwalls playing, the mic was set up at "seated" ear level at my listening position. Whether the sub was turned on or not, the mic position never changed. The only time I moved the mic was when I did the two 1 meter measurements on the Cornwalls. Also, I'll take a couple pics of the mic in the different locations.

Hmm... How about for anodizing aluminum K-400 horns?! [] Or better yet, Altec 511B horns?!! []

Now I know!... It's for recharging alnico magnets on old K77s and K-55s! [8-|]

Hmm... Self-powered Cornscalas. That's the power supply section for the two amps, one highpass and one lowpass. []

Yeah, I didn't think about that. Oh well. [:$]

Well, bring your system over sometime and I'll measure it for you. LOL You can measure your system. All you need is the TrueRTA software, a Behringer ECM800 calibration mic and either a mic preamp or small mixer with +9 to +48V phantom power. Oh, and it helps to have a somewhat decent soundcard in your computer. []

Yeah, that's the same tacky electrolytic that I'm using in all three of my front speakers also! []

Yep! I also forgot one picture. Here's a pic of the mic pre and TrueRTA up and running. I had the Klipsch forum up on the other screen, but that was boring looking compared to the wallpaper on the desktops. [] BTW, that is a professional model/body builder that I'm good friends with. I'm working on designing her a website as we speak. hubba, hubba! LOL []