chops
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Posts posted by chops
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"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!"
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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...
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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 [
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Chops. It is embarrasing how many damn Solen caps I have laying around from testing/trying stuff.
jc
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
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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?
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 $50-100 on crossover parts every couple of weeks to do experimental work on crossovers and end up with a bunch of wrong parts because those calculators told me the wrong values.
That's why I am asking so many questions and wanting to do proven mods so I can get where I need to be. That way, I can be up and running ASAP and get all the bugs worked out before taking the plunge of building a pair for myself with all new and better parts.
As much as I'd love to do all of this on my own, I can't. I'd much rather leave all the guess work up to the ones who know what they're doing. And trust me guys, all of your input is greatly, greatly appreciated! [
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I, and as Terry will tell you ...
don't belive you will blow that Altec driver.........
the most important limit will be reached in Excursion, and the power the driver recieves <600 Hz...
what's the \' Half Power " point ..???
350 Hz ....?????
where both drivers in a system recieve the same wattage
don't forget the Fc of the 511.............
ain't what it's rated at .... DJK explained this a while ago....
I was Wrong ...!!.........[:$]
well, it was the literature, that was misleading .....[
]Duke,
the most important limit will be reached in Excursion, and the power the driver recieves <600 Hz...
what's the \' Half Power " point ..???
350 Hz ....?????
where both drivers in a system recieve the same wattage
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.
don't forget the Fc of the 511.............
ain't what it's rated at .... DJK explained this a while ago....
I was Wrong ...!!.........[:$]
well, it was the literature, that was misleading .....
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.
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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?
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"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?"
Not quite. When you do that, you're stepping down the impedance of your midrange from 60 ohms down to about 8, and this changes the parts values. Reading through the following thread will answer a lot of your questions about this, but will raise some new ones as well. http://forums.klipsch.com/forums/thread/606374.aspx
Like me, JC has tried just about everything, so definitely get his input. I'm pretty sure we've reached similar conclusions on some things. I will say that with a room the size of yours, and if you're into live listening levels -- this pretty much mandates higher order filters (unless you move your couch up:) to keep distortion levels down. This subject taken as a whole is extremely complex, and it doesn't help matters that people who do a lot of this kind of thing invariably come to different conclusions on some things. However, the advantage of learning and doing it on your own means you will eventually draw your own conclusions -- and find the way that works best for you personally (your room, gear, music, and listening habits). In another thread, 'speakerfritz' mentioned the necessity of a matrix of sorts for all of these different networks. He also liked the 'good, better, best' approach that Al uses on his website. I actually had this need mentioned to me by Mark Deneen in a telephone conversation last year -- my response was that it was impossible to do. There are simply too many variables to juggle. Not only do you have the various acoustic and weaknesses associated with design -- but you have the fact that people just plain hear differently. Some are just used to a certain sound, and have trouble if the signature strays too far off from the thing they are used too. I'm one of those people, and since getting into this 30 years ago -- I have always gravitated towards loudspeakers using low order filters. The truly funny thing is that I didn't realize this until I became interested in crossovers and started learning about the designs used in the speakers I grew up with: they all used first order designs -- with the exception of the Old Advent, which was second order. I'm still there -- I love the sound of a first order filter section on a horn midrange.
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.
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My hearing is in question but I love stuff that sounds like crap. Infact, I am partial to the smell of it.
Chops, I am no expert. I have piddled a bit with this CW K33 bass bins. The 511/902 combo is very good.
I would stay the course of what was mentioned above. The one strong point I will add is to consider getting away from crossing the tweeter at 4500Hz. The 902 does great out there and there is no good reason I can think of to cut the 902 off at 4500Hz.
The second strong point is to not rush into a new change quickly. Dean is right on this one (he has said it to me before too). I used to get too excited about a particular mod or change and then make a decision. It is quick and easy to mod/upgrade but its evaluation takes awhile.
You are on the right track. The 902/511 combo is a winner in my book.
jc
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
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, 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.
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
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How bout sub + cornwall of the same batch? Or did you move the mic already?
That would be these two...
Quick Sweep:
Pink Noise:
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JC's already admitted he can't hear worth a crap, wait -- maybe what he said was he likes things that sound like crap -- and Terry can't hear anything until it gets above 110dB.
Stay the course Charles. Work with the simple filters/mods and get your ears dialed in to what they do to the sound. If you move too fast, you'll have to go back and do it all over again! I'd like to see you try some different caps too -- before you get brainwashed into believing they all sound the same.
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-|]
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Chops,
At this point, the cat is out of the bag, so speak to Dr. Cullison about the "Alcorn" crossovers. They were designed for my CW bins, 511b/902 mids, and the K77 or CT125 tweet. Very sweet mids & top, and very tight LF.
tc
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
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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...
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I would be a lot more interested in the curves in the left monitor myself those are far more natural and realistic looking- bet they sound great! Chops, we have got to get together.[
]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! [
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Well I would be interested in a higher resolution scale if it's not too much of a hassle. I'm actually interested in the raw response of your sub only too.
Your response is actually quite interesting and I think you've got a beneficial phase cancellation thing going on.
And does the TrueRTA program measure THD as well? Usually these programs do, but I've not played with this one. The reason I ask is that the response measured from 30-10Hz for the cornwall without a sub doesn't make sense. Are you perhaps hitting the noisefloor of your room? What volume were you doing these measurements at?
And are you moving the mic around when switching around? It doesn't make sense why adding a subwoofer introduces a 3/4 octave wide 20dB change centered around 150Hz.
I hope you don't mind me trying to interpret your graphs...phase and time information would be beneficial, but this is definetly a much better start that just using your ears or a ratshack meter [
]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.
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Hmm... How about for anodizing aluminum K-400 horns?! [
]Or better yet, Altec 511B horns?!! [
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Now I know!... It's for recharging alnico magnets on old K77s and K-55s! [8-|]
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Hmm... Self-powered Cornscalas. That's the power supply section for the two amps, one highpass and one lowpass. [
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You should try boosting the resolution of the dB-axis...we don't need to see +20 to -160 [
]Anyways, it's really not that bad at all.
Yeah, I didn't think about that. Oh well. [:$]
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Chops,
That is some pretty good response,wish I could measure my system to see where I am at!
Greg
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. [
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Yeah, that's the same tacky electrolytic that I'm using in all three of my front speakers also! [
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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 [
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Preparing for Jubilee build
in Technical/Restorations
Posted
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. [
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Charles