tourmax

This might just be my inexperience showing, but I'm not really understanding how the "PRT" tweeter is a lot different from the AR cone tweeters, other than the obvious response differences, which I'm guessing is as much down to the size of the cone as much as anything else. It just looks like a cone tweeter that is attached to the phenolic ring instead of the top/front of metal basket itself and the phenolic ring looks like it's bonded to the metal basket. Would not that make the phenolic essentially "rigid" like the metal basket would be anyways? Unless it's something like the phenolic changes the response (resonance I'm guessing maybe?) as opposed to the metal basket. ....

I get that. but I’m also just starting to absorb more details about crossovers (new to the details of them) and it seems the crossover network is just as important as matching tweeter and woofer so they compliment one another vice one “shouldering” the other to the side a bit. gotta start with good drivers but it seems you still have to do the work to match them in the crossover. seems theres a whole tone of math in it too. Thankfully, I’ve run across a couple “freeware” programs that lets you play around with impedance and resistance to see how the curves move. Reading it on a page or working out the math is one thing, watching how the charted curve moves is another. I’ve had more than one “aha!” moments playing with the values. like I said, I’m just starting to learn crossover networks, but it seems that you need to work it all as a system to me so far. cheers

Yes, I'm serious. There's a grand total of 1 million people in my entire province and it's generally considered economically depressed (and has been historically). There's not much around and what does often show up is lower end or box store level at best. The few rare decent pieces that do show up, people want stupid amounts of money for. Shipping speakers in is cost prohibitive because of the size and weight and drives the total cost up to (if not past) anything you might find locally. As an example, my simple AR4x's can go for anywhere from 400-600 bucks here. People have asked more, but they don't seem to move in the 600-800 dollar range. I've had people I don't even know get a hold of me and ask me if I want to sell mine when word gets around I have two sets. I was lucky enough to grab them about 10 years ago for 100 bucks a piece in "distressed" cosmetic condition and someone who was in a "financial bind" and was selling off stuff to....well, you know how that goes. He even called me 6 months later to see if I woudl sell them back to me at twice what I paid. Nope......;) My Sansui 8080DB? Bought about 8 years ago and it was cosmetically a wreck, half the output transistors were blown, multiple transistors on the driver board were blown, transistors on the power board blown, a circuit trace burned clean off the power board, more out of spec caps than I can count and drifted "fusistors" all over the boards. And it took nearly two years of cleaning to get the absolute [i]REEK[/i] of cigarette smoke to finally go away. It rode home int h bed of my truck and you couldn't barely be in the room with it when I first brought it home. the wife refused to let me bring it in the house until most of the stench was out. I was still lucky to even find one at all and I still had to talk the guy [i]DOWN[/i] to 400 bucks for it and throw in some work (IE: labor) on some of his other equipment. It's a different story in the 'states, where people seem to be packed on top of people everywhere and stuff is plentiful and relatively clustered around major areas or within reasonable driving distance. The closest "larger" population provinces are a good 10 hour drive by highway to even get to what would be considered a major center. It's just not like that here. Here, you take what you can get or you don't get nuttin'....or you pay through the nose to have stuff shipped in and hope it shows up intact, which it rarely does. I swear they must have hired the "Samsonite gorillas" here to handle anything larger than an envelope. Not a bad idea on running the wires out of the ports, at least for testing. That hadn't occurred to me.

This was actually helpful in my understanding or what is going one. Perhaps it will help someone else trying to at least get a grip on "attenuating and shaping" a tweeter's response: https://www.youtube.com/watch?v=zoLBnEdVP6c Obviously, I still have a lot more to learn, but at least I feel like I have a starting point now. My next challenge seems to be finding out the sensitivity levels of the Polk tweeter and mids. They give the sensitivity overall in the usual ad hype, but not separately for the tweeter and mid. If I understand that vid correctly, I'll need those specs before I can even get a start or it's all just guess work....

Thank you for your replies, but they don't answer the questions I'm asking.

I do have a 10 band in the system: And I have thought of changing things up a bit so the EQ affects all the sources, but it currently only affects the tape player. It's in serial on the "tape in" with the cassette player, mainly because I find compact cassettes so variable in playback "quality". I'd like to do something more "fixed" in the speaker because I find the EQ encourages me to "fiddle" too much with each song rather than enjoying the music for what it is. Fiddling with all those sliders gets old pretty fast though and I'm always feeling I can get it a little better, which means more fiddling. That's fine with pre-recorded cassettes because I accept that their quality s going to be variable, but not so much with CD's, turntables, etc. I prefer the signal to come though neutral tone controls for those sources. It's just a bit too bright everywhere and I'd like to tone it down overall a bit. Seems finding a way to calm the tweeter down a bit is the more applicable way for me. I could be wrong though, I'm no expert on this. I just know what I hear and know what I like when I hear it....I'm like an art "non-connoisseur" in an art gallery: "I may not know art, but I know what I like"

I recently took my AR4x's out of the system. Wonderful speakers and vintage favorites for me, but you could just tell they weren't a proper match for the power my Sansui 8080DB was capable of putting out (85 WPC). Over 25% vol you were considering rolling off the bass a bit (for the 4x's health) and if you got anywhere close to 50%, you could tell the 4x's were right on the cusp of screaming for mercy. I've been watching for a while now for a set of vintage speakers to show up that are more a match for Suey's power, but anything that even looks like it's only half worth going for a viewing is obscenely over priced. Like 1-2 grand for a set of advents that don't even have original drivers in them. Even stuff that's been poorly modified or needs serious work before it can be used is foolishly overpriced these days. Sometimes even higher than even a good set of working vintage speakers would be. People are just trying to cash in on their old junk by taking advantage of the recent "hipster" trend towards "vintage audio" it seems. Sign of the times I guess, make as much money as you can for even the worst junk. "One born every minute" mentality...no thanks. I'll pass on that. So for the time being, I've pressed a couple tower speakers I have into service. They are Polk RTi A5 towers and a powered subwoofer: Good for 250W per speaker. They can handle the power Suey puts out fine enough. The AR's have it all over them in the looks department. The sleek, black, tapered cabinets are cool looking, but just don't fit with the rest of the vintage vibes in the room. But I can deal with it (for now) if it means not stressing the AR's up dangerously close to distortion. Even with Suey dialed back, an occasional bass or drum hit would give the AR's a little breakup and distortion noise if you had the volume juuuust a little too high for them. These Polk's take it without breaking a sweat. Subwoofer was an easy installation as the 8080DB has a second set of pre-outs which go right to the power sub. Plug in the RCA's, plug into the wall socket, flick the power switch and it's up and running. It even has an auto standby/off circuit so it turns itself off when there's no signal. Set it and forget it. Fills in the hole below the floor standers 30 hz bottom end nicely. The sub has adjustable volume and crossover, so it's easy to get the bottom end listening just right. But the towers were bought for a HT system. They sound fine on my two channel system and can get plenty loud, but being biased toward a HT system, they can sometimes be too "bright" on the top end. They "bottom out" at 30hz, but the sub fills in below that so it still sounds great on the bottom. I've been googling to see how to pull back the top end a little bit (or just "mellow" it a bit) and it runs the gamut from reworking the crossover network: to running L-pads and fixed resistors inline and parallel to with the tweeters. I honestly don't know a lot about crossover networks other than the very rudimentary basics. Like you need one, there's resistors, capacitors and chokes and it's meant to limit what freq is reproduced by which driver. I'm aware there's 1st, second and third order crossovers, but not much more than the fact that there are different ones. Which seems mostly dependent on how many drivers you're using. I'm guessing the one in the RTi A5 is second order, because it has two chokes. there's three drivers, but two chokes, so I'm guessing that still makes it 2nd order. Honestly, I'm just turned right around at this point. I just want to pull a bit of the highs out of the tweeter to bring them a little closer to two channel music listening while i keep looking for something vintage/better for music. Something that's reversible in case I end up taking the RTi's back ot of the system. An Lpad to figure out a resistor value I prefer the most and then soldering in fixed resistors is probably the way I'd prefer. If that would even work that is. I really don't want to be cutting into/drilling the cabinets....but cutting and soldering int eh wiring is OK with me because it will be inside the cabinet and not visible. I'd ask this on one of the other big audio sites, but that is just going to draw too may comments that aren't helpful and at worst, trolling and inflammatory. Any help?

Now thats interesting! Probably beyond what I would do with a brand new set, but I’m interested in what the results are. I’m an old “greasy paw” and also can’t leave much alone “as is”, so I totally get the need to tinker and see what you get. Carry on!

Yeesh…..

They’re done and I’ve used them a bit. they sound nice, perhaps just a touch of “boom”, which I’m accounting to the port in the box. Nothing objectionable, just noticeably different from the AR’s sound. The ar4x’s are a bit nicer sounding, a little bit smoother and more “accurate”, if that makes sense. Plan is to put the esm-3’s up in my hobby room, paired with a Pioneer sx-680 I’m currently rebuilding: 35wpc should pair nicely with these. The 680 has a blown output, which is fairly common on these. The “darlington power amplifier” IC is no longer made, so I’m first going to try an “eBay special” and if that doesn’t work, I’ll build a discrete component network to replace the stk0039 component. There’s even “kits” available for this on eBay, although the kit (ie: builds two stk0039 replacements) alone is worth more than the little 680 will ever be worth. I have a fairly “mint” pioneer pl-200 semi auto turntable: and a Sony 5 cd carousel player to go with them as well. Nothing “high end”, but will work just fine for casual listening chores while I’m tinkering with something else (ie:hobby). Canadian speaker manufacturers were given access to the NRC facilities, which, among other things, had an audio/sound research lab that was world known at the time. The program was part if a larger program and put in place to help the Canadian audio industry compete on a world stage. Basically, it was intended as a gov’t sponsored “boost” to the overall economy by trying to “bring up” all market segments. Its just so happened that Canadian audio company’s also benefitted largely from the program and accessing gov’t sponsored research facilities. here’s a little info in it: https://www.axiomaudio.com/nrc ignore the add hype in the write up. The NRC stuff is accurate though. I don’t think NRC is involved with the audio industry in Canada any longer because, well….there’s really no audio industry here anymore. Everything is like everywhere else these days: once storied and respected brands bought out by conglomerates and cheapened down to the lowest possible extent to maximize profits. Energy is still around, but foreign owned and they make cheap things like bluetooth speakers, bug zappers, etc. Sad, but its the way the world is now….

Noted. Thanks.

You know, I read that and it went right out of my head when I ordered. Oh well. I guess a little "fine tuning" headroom with some resistors isn't that bad a thing either. Any recommendation on a min wattage for resistors in the tweeter path? 5W sound appropriate or can/should I got a bit lower?

Hmmm, the tweeters I just ordered are 8 ohm but I’m reading various threads on the forum that 4x’s are anywhere between 4 and 6 ohms. Did I order the wrong impedance tweeters and if I did, can I bring them closer to the proper values with some resitors?

Well, I’m not admitting defeat on the original tweeter rebuilds/repairs, but decided I needed a “backup plan” just in case. ordered a pair of the phenolic ring tweeters off an eBay seller. Still came out to just under 100 bucks CAD all said and done. Tried parts express and others and they only ship here by fedex/ups/etc and that means high shipping charges and a nasty “brokerage” surprise when they do arrive. Figuring in exchange rates, they all came to a fair bit more than 100 CAD. Hopes are still to rehab the original tweeters, but if it doesn’t work out at least I have a viable alternative.

I’m in Canada, which means exchange, taxes and duties and international shipping charges. They quite a bit get more expensive, frighteningly fast. Believe me, if I could get a pair here for 50 bucks, I’d be all over it. Maybe later in the summer when funds are a little bit more freed up. Tax time here and that is always a tight time…

One freshly glued and one partially dried: Used Aleene’s for the first time. Guess I’ll see if it lives up to its rep. Was easy to use and position surrounds for sure. Fed them both a 30hz signal after initial positioning and all seems good to go. I’ll give them a good 12-24 hrs to fully cure and then back into the boxes they go for a "test run"....

You're probably right, But I'd like to try and protect these old speakers as much as I can. I was planning to fuse the tweeter and woofer separately so I can use different values for each. Might be an exercise in futility, but if it saves them just once from an abnormal condition, it's worth it to me. I'm not really worried about a fuse impacting a signal path "sonic-ly". Not many fuses are as thin as those fine wires crossing the basket to the voice coil gap. Hmmm.....which sort of shoots down the argument for including a fuse when I think about it....lol!

second woofer basket cleaned: Good place to stop for the day as my fingers are cramping now. Tomorrow I'll start work on cleaning the cone edges.

Cone and basket cleaned and the surround just sitting on the cone to give it a chance to "relax" to the cone's shape: I'll put that aside for a day or so while I start cleaning the second woofer.

I picked up a set of ESM-3's a couple years ago at the thrift store. They had 20 bucks on the pair, so i grabbed them. Didn't look very closely at them as 20 bucks is not a big sum of money for even a cheap set of speakers. They're right about the size of my AR4x's, but a little less in weight. Still have some good "heft" to them, but they do seem like a lighter construction cabinet than the same sized AR's. Read up a little on them once home and they seem to be reasonably well respected for bookshelf speakers. Fine examples of "pre-buyout" Energy branded (Canadian built) speakers. Add hype seems to indicate they are patterned on "Energy Pro 22's" which seem to be respected monitor speakers. The few "testimonials" I can find online seem to be pretty "glowing", several mentioning low end response. They are a ported box, which in my experience makes speakers kind of "boomy". I tend to prefer tighter sound from my bass response. I guess I'll see if these are "boomy" or capable of nice lows without that "boominess" I've come to expect of ported designs. So it seems they're worth the couple bucks (and my labor) it will take to rehab them. Who can't always use another project? Pop the grills off and the woofer surrounds drop out on the floor pretty much as dust. Ok, not really that unexpected. I meter the woofers and tweeters to make sure the coils are not damaged and they come back as good. Must have been sitting idle somewhere for a while and either the sun or time has just crumbled the foam. "Audiodogs" in BC has the proper "filleted" foams for not a lot of money, so I order up a set. Then life got in the way and they got shelved for the past two odd years. Now I have the time to get back on them. Woofer comes out of the first cab and there's a "brace" from the rear of the cab to the back of the woofer: First time I've (personally) seen that. I guess it's meant to help cut down on resonances? Dunno. Nice layer of fiberglass like fill in the case. No cap in the crossover, just a ceramic resistor and a coil. That's another new one on me as I'm used to at least seeing a capacitor in there somewhere before the tweeters. I may have to read up on crossover designs to see if a cap is beneficial to add to this one. Vintage speaker drivers are hard to come by and I don't want to leave these "hanging out in the breeze" should there be an audio spike of some sort fed into them accidentally. And while I know it's generally "controversial", I may look at fusing them as well. Potentially giving up a little SQ is worth it if it gives "unobtainum" vintage drivers a better chance at longer survival. I recently had a set of AR4x's "pop" their tweeters and it's proving to be a bit of a nightmare to source replacement originals, so I'm fine with accepting some limitations to protect drivers from a "mistake". Start cleaning the first woofer: Poly cone so it's relatively easy to clean. IPA seems to soften things up nicely. There's still a fair bit of work to do to them, but nothing overly difficult. It's just patience and time. The mesh dust cap is interesting. That's new one on me too. Taking a break from the grubby work of cleaning the woofers, I give the grills a clean: They had the typical 40 years of dust and dirt splatter on them and they clean up pretty nicely. They still need a few more rounds of cleaning, but I want them good and dry before going at them again. It's audio mesh over particle board, so too much "wet" all at once is not a good idea. One grill has a small "rip" in one corner, but it's on a bottom outside corner, so it's not really visible when installed. I'll probably black out the bit of wood material showing and use a little "rip stop” product to bind the edges and keep it from getting any bigger. The grills are also missing one of the "ESM" badges. Not sure what to do about that as I'm never going to find another one. the one that's still there is just plastic, so I may make another I can print out on the 3D printer and paint to match. The veneer also looks very "thirsty, so I give "Howard's Restor-a-Finish" (neutral) a try: Not bad, but that wood was some thirsty. Sucked it right up and after a light rubbing with a clean cloth, the veneer looks quite respectable. There's still the odd light scratch here and there, but nothing that jumps out at you. They're 40 year old bookshelf speakers, so it's not unexpected wear of any sort, These actually must have lived a reasonably comfortable life compared to what usually happens to speakers at this end of the market spectrum. You might think these would be vinyl coated cabs, but they're not. that's a wood veneer over that particle board (or whatever type of composite board it is).

Thanks gents. I’ll get on those caps. I’ve seen the scans of AR recommendations for fusing in the library section. I’ve also seen the “signal loss” argument on the internet in places. I’m more concerned with protecting these old speakers than I am loosing any signal. It’s not like I’m building some competition sound system or anything like that. It’s just a simple home system, so I’m willing yo give up a little something in order to possibly save them this type of damage if it ever happens again in the future. whats the difference between the suggested brand fuses and a commonly available “fast blow” fuse?

Thank you. Thats very helpful.

You may have noticed my recent thread about the tweeters in a set of AR4X's being damaged by a high freq feedback squeal when a microphone was plugged into my Sansui 8080DB. It's not something I do (was bud "jacking in") and there were a few other things that conspired to make the loud feedback squeal. It now appears it broke/melted the voice coil wire to the terminal in at least one of the tweeters. I'm currently using a second set of AR4X's I had in storage. I seldom have "Big Suey" much over 25% volume, 50% being a rare occurrence because the pressure level in the room at that volume is just not enjoyable for me (room is only 10x10). As we all know, these speakers are becoming hard to come by and I seem to prefer the AR4X's over most other speaker sets I've tried, so I'd like to protect them from unexpected "spikes" if I can. Specifically, I'd like to protect the tweeters from the type of feedback "spike" they experienced and damaged them. I don't plan on doing anything that would have a possibility of damaging them, but I wasn't expecting someone else over for a visit to do something like jam a mic in at volume before I could do anything about it. I suppose there's also the specter of a fault in the amp taking them out too as 1970's SS electronics won't really do a lot to protect components downstream if it has an internal fault. Would there be any sense to "fusing" the AR4x's? Perhaps fuse the tweeters separately (ie: inside the box) from the main input on the back? I've seen the AR scan on this site's repository, but it seems to mainly talk about a whole speaker protection fuse. I don't have an issue with placing a fuse internally to the box to protect the tweeter if that need be. Opening them up to check/replace a fuse is infinitely preferable to me than having to repair/replace a near "unobtanium" tweeter. Another quick question: is it possible the caps in the speakers need to be replaced? I would have though they would have taken the hit instead of the tweeters if they were still in good shape. As far as I know, they are originals (IE: the big "wax box"). Maybe I should just replace the caps on "spec"....

Well well. I didn’t get to do a lot with the tweeters today. Busy busy. But sitting in the music room at the end of the day enjoying a tea and the one tweet I’ve lifted the cone on is right in front of me. I grab a small thin probe and work the yellow insulating material back so I can see the terminals inside. One has the voice coil wire right to the inside part of the terminal. I gently move the material around a bit and find the other terminal and its plain to see the voice coil wire has detached from the terminal. Either broken or perhaps it “burnt back” a bit. At least that gives a little hope the coil on the tube is still serviceable. Perhaps I’ll be able to reconnect the broken voice coil wire back to the terminal. Will be quite a bit of fiddly work to do that if I don’t completely remove the cone. I may make an attempt, but am wary of getting even a fine tip on the soldering iron that close to the cone (even on low heat). I might be able to save these tweeters after all….

I've recently had a set of AR4x's blow their tweeters. They meter as an open circuit. So now I’ve got to replace those tweeters if I want this particular set of AR4x's to sing again. Finding AR anything around here is as hard as finding a 2lb gold nugget and its probably going to be a while until I will run across 2 more on ebay or the like. New style replacements are an option, but I've got time to wait for originals to show up. I just pressed a second set of AR4x's (that were waiting a restoration) into service. So, I figure I’ve got not much to loose to try and pull these apart. Can’t make them any more “dead” than they already are. They'll either get stronger after the operation or die on the operating table. Not much to loose other than a bit of my time. Out on to the desk they go. First thing is to lift the glued edge. But I need to be very gentle so as to not destroy those cones and their integrated surrounds. About 2 hrs of gentle work with a fine, thin hobby blade and dabbing IPA with a cotton bud lifted the edge. Talk about slow and nerve racking! Fraction of an inch at a time! But the edge is now lifted. Interestingly enough, its not open space behind the tweeter cone but a fibrous like insulating material. I guess AR thought they needed more control over the cone movement than just a closed back. To be honest, these are the first tweeters I've ever opened so this may be a common practice. There's no “tinsel wire” like you would see on larger speakers so I’m guessing it comes out the side through the middle of the terminals. Seems to make sense as the middle on the terminal blocks have solder down in the middle “holes” and there's no other evidence of the wires on any other part. I actually gave re-flowing the solder a try in case it's a cold solder joint causing continuity loss, but no dice. They stay dead open. Looking more and more like it's the voice coil shorted internally. I may have to take a try at rewinding it and see what I get. I sometimes rebuild motors by rewinding the coil, so it's not a new thing to me. It's just going to be much finer wire. OR maybe it won't be "do-able". At least I'll find out one way or the other..... And that's where I left them for the day. My nerves are just shot from lifting the first surround. Tomorrow, I’ll see about removing that solder and if I can get the cones/coils out. This is not a place to be “rushed”. These parts are small, fiddly, old and easily broken. And my nerves really need a break right now…