My snowbird neighbors finally showed up with the speakers they picked up for me in Indiana (I bought them off USAudiomart in Nov or early Dec) they just happened to live 30 min up the road but I would have to wait……………until they got here!
Tried them out and they were pretty much what I expected, smooth and clear even at high volume. Two things stuck out, one was an obvious difference in the top end between the two……seeing as these are from the 80’s I pretty much assumed the tweets and mids were gonna need rebuild and am packaging them up to send off to Richard So as he’s the man for ADS! (Actually the only man with parts)
The second thing was a bit more surprising, theres a quite noticeable box resonance in the upper bass / lower mids…..the bracing in the box only amounts to a 2” rib of 3/4” material on each side centered front to back and one piece same size across the front (see pic) I’ve never seen a box braced like this and its fairly obvious why not! So in answer i’ll just put in some cross brace 1” dowel in each direction…….Oh and I reckon there‘s a third thing that kindly surprised me is the orientation of the inductors all on the same plane!?
I’m going to recap the original xo‘s but I also want to build a pair from scratch with better quality components just for the heck of it (please no lectures on the waste of money, snake oil blah blah 😛) after tracing/mapping out the xo’s three times to make sure I got it right I end up with this (see pic) kindly odd can anyone explain that mid configuration? (See pic) tweet is reverse polarity and woofer looks normal.
Does anyone have a schematic for the L880/2 ? I’d like to figure out the inductor values without having to desolder them (unless the DATS V3 can measure accurately in circuit?)
This is the first ferrite core inductor i’ve ever had on a woofer(I take that back, my NS 670’s has them) can saturation come across sounding as a resonance?
edit; forgot to ask should I put a fuse in place of that polyswitch (if so what rating?) or just remove it?
edit II ; upon thinking about removing that polyswitch it dawned on me they do have a resistance even when closed….correct? if so would need a proper value resistor there, right?
Thanks,
MMB
Tried them out and they were pretty much what I expected, smooth and clear even at high volume. Two things stuck out, one was an obvious difference in the top end between the two……seeing as these are from the 80’s I pretty much assumed the tweets and mids were gonna need rebuild and am packaging them up to send off to Richard So as he’s the man for ADS! (Actually the only man with parts)
The second thing was a bit more surprising, theres a quite noticeable box resonance in the upper bass / lower mids…..the bracing in the box only amounts to a 2” rib of 3/4” material on each side centered front to back and one piece same size across the front (see pic) I’ve never seen a box braced like this and its fairly obvious why not! So in answer i’ll just put in some cross brace 1” dowel in each direction…….Oh and I reckon there‘s a third thing that kindly surprised me is the orientation of the inductors all on the same plane!?
I’m going to recap the original xo‘s but I also want to build a pair from scratch with better quality components just for the heck of it (please no lectures on the waste of money, snake oil blah blah 😛) after tracing/mapping out the xo’s three times to make sure I got it right I end up with this (see pic) kindly odd can anyone explain that mid configuration? (See pic) tweet is reverse polarity and woofer looks normal.
Does anyone have a schematic for the L880/2 ? I’d like to figure out the inductor values without having to desolder them (unless the DATS V3 can measure accurately in circuit?)
This is the first ferrite core inductor i’ve ever had on a woofer(I take that back, my NS 670’s has them) can saturation come across sounding as a resonance?
edit; forgot to ask should I put a fuse in place of that polyswitch (if so what rating?) or just remove it?
edit II ; upon thinking about removing that polyswitch it dawned on me they do have a resistance even when closed….correct? if so would need a proper value resistor there, right?
Thanks,
MMB
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At first glance it seems to be second order filters all-round, padded mid and inverted tweeter.
Regarding the core, not so much resonance as distortion.
Regarding the core, not so much resonance as distortion.
This is a 12dB/oct 3-way x-over right from the book. If I was you, I would not use any "better" parts until I measured the frequency response of the whole box.
It may be quite interesting to see. I'm not sure the woofer is original, so there is a great chance it is not matched to the x-over.
For a first listening test, please change the electrolytics for new ones, even if they measure OK. They can cause funny effects on the speaker.
For the "resonance", apart from the caps, remove the woofer and look for the wires that go from terminal to cone. One may be bend the wrong way and touch something.
So with new caps, listen to or even better, measure them.
You sure have some speaker of known, good quality you can use as a reference. Connect one on each side of a stereo amp and compare using the balance knob.
If you like the sound, maybe improve them, but do not buy expensive parts if they disappoint you. A new x-over with high quality parts may round some small edges, but the character of the speaker will stay. They may improve from a new x-over, but with other values than original, something a frequency sweep will tell you. So just changing for the same values may be waste of time and money.
These speakers did not sound very exiting, even when new, more a neutral speaker. A matter of taste.
PS the inductor should be the last part to make any problems.
It may be quite interesting to see. I'm not sure the woofer is original, so there is a great chance it is not matched to the x-over.
For a first listening test, please change the electrolytics for new ones, even if they measure OK. They can cause funny effects on the speaker.
For the "resonance", apart from the caps, remove the woofer and look for the wires that go from terminal to cone. One may be bend the wrong way and touch something.
So with new caps, listen to or even better, measure them.
You sure have some speaker of known, good quality you can use as a reference. Connect one on each side of a stereo amp and compare using the balance knob.
If you like the sound, maybe improve them, but do not buy expensive parts if they disappoint you. A new x-over with high quality parts may round some small edges, but the character of the speaker will stay. They may improve from a new x-over, but with other values than original, something a frequency sweep will tell you. So just changing for the same values may be waste of time and money.
These speakers did not sound very exiting, even when new, more a neutral speaker. A matter of taste.
PS the inductor should be the last part to make any problems.
The feller bought them new and has (said) never been inside them, all indications lead me to believe they are original woofers. The box is built quite light/cheap for what it is and more than likely the problem.
Spending needless money on audio is the only vice I have left……..don’t try to turn me into one of them frugalphiles! 🤣
edit; just compared them to every stock photo on the net I could find……they are original woofers.
Spending needless money on audio is the only vice I have left……..don’t try to turn me into one of them frugalphiles! 🤣
edit; just compared them to every stock photo on the net I could find……they are original woofers.
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You are right about the woofers, I thought they were recessed and had "ears", but the 10" is the (oonly?) one with a round cage.
Anyway, look for the leads to the voice coil and change these 45 year old caps. It may solve some problems.
Anyway, look for the leads to the voice coil and change these 45 year old caps. It may solve some problems.
They get triggered and they change in composition. Measure the resistance. Consider replacing it with a small resistor of the original value, as you should be able to trust yourself not to blow these.
Are you sure the lead from the left picture does not tap at the membrane when the cone moves?
As long as you experiment with the speakers, I would leave the poly switch. Gives you some security. So I don't advice to remove it.
On the other hand, I do not trust them. Some say they add distortion. With a stable amp in a permanent installation it should not be needed.
As long as you experiment with the speakers, I would leave the poly switch. Gives you some security. So I don't advice to remove it.
On the other hand, I do not trust them. Some say they add distortion. With a stable amp in a permanent installation it should not be needed.
Both the polyswitch measure under 1/2 ohm so they really don‘t attenuate much, maybe throw in a 1R 5w in its place to act as a fuse of sorts?
turbo I just checked and the lead moves with the cone quite well (not closer as it moves) the angle of the pic makes it look closer than it is also.
edit; Big inductor for woofer is 3.0mh ……it was visible on the second one when I took it out.
what of the orientation of these inductors…….I thought that was a big no no?
turbo I just checked and the lead moves with the cone quite well (not closer as it moves) the angle of the pic makes it look closer than it is also.
edit; Big inductor for woofer is 3.0mh ……it was visible on the second one when I took it out.
what of the orientation of these inductors…….I thought that was a big no no?
Can you run the woofer from a generator while it is out of the cabinet? Tune until you find the frequency that makes noises?
The 10" is pretty large and the suspension soft . The cone may have deformed the suspension. If so, moving the woofer 180° (or the whole cabinet) may cure the problem.
Are you sure it emmits from the woofer?
The 10" is pretty large and the suspension soft . The cone may have deformed the suspension. If so, moving the woofer 180° (or the whole cabinet) may cure the problem.
Are you sure it emmits from the woofer?
If I had to make a educated guess its between 300 to 500 hz……lower male vocals really excite it. Its a overall sound (as in hard to pinpoint) much like you’d expect from the cabinet.
I’m limited on diagnosis time so basically just doing everything possible to eliminate it…….tightening up the cabinet, i’ll flip the woofers like you suggest, not sure if that 130uf shunt cap matters for resonance but all caps will be new.
I did notice when I put the metal grills back on to put them aside they rattled quite a bit so did the whack test and they sounded off like you were beating on one of those old aluminum screen doors from the 60’s…….so I might want to make up a speaker cloth grill as these cannot be run without protection…..the mids and tweets have a coating akin to flypaper and our two 100 lb dogs shed a grocery bag of hair every week!
I’m limited on diagnosis time so basically just doing everything possible to eliminate it…….tightening up the cabinet, i’ll flip the woofers like you suggest, not sure if that 130uf shunt cap matters for resonance but all caps will be new.
I did notice when I put the metal grills back on to put them aside they rattled quite a bit so did the whack test and they sounded off like you were beating on one of those old aluminum screen doors from the 60’s…….so I might want to make up a speaker cloth grill as these cannot be run without protection…..the mids and tweets have a coating akin to flypaper and our two 100 lb dogs shed a grocery bag of hair every week!
And I presume they're similar, that could be a sign they're not causing problems?
On the other hand you mention the top end is not balanced between the two. Check all the drivers' resistances and find out if they have ferro-fluid.
Tweets and Mids going out tomorrow to a feller (Richard So) who used to work for ADS and bought all the remaining diaphragms and such to rebuild them……so now they’re unobtanium besides through him and he only offers them as a full service not parts. Plus theres a good chance he’d do a better job at it than me anyways!
Just measured Re ……tweets 3.1/3.2 Mids both 5.9 so could be the ferro fluid (Which they do have).
edit; to answer if the polyswitchs were similar .48/.47 so yes, but really don’t like the idea of them being there, i’m sure it was just to keep the drunken masses under control on Friday nights!
Just measured Re ……tweets 3.1/3.2 Mids both 5.9 so could be the ferro fluid (Which they do have).
edit; to answer if the polyswitchs were similar .48/.47 so yes, but really don’t like the idea of them being there, i’m sure it was just to keep the drunken masses under control on Friday nights!
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Does anyone have or know where to find a xo schematic for the L880/2 ?
would like to know the values of the inductors used.
would like to know the values of the inductors used.
After several hours of listening to them things are gelling quite nicely, impressed by these cheap M.D.L electrolytics and even more impressed with the Wima MKP10 on tweeter duty, its transparent and colorless, also inexpensive.
Anyone contemplating rebuilding their ADS crossovers these components work very well !
The rebuilt tweets and mids sound as if new so no regrets on that.
Boxy resonance is still there on male vocals but not as pronounced, is the same with or without the metal grills……I did flip the woofers 180’ as turbo suggested, i’m pretty sure its just the box, gonna try some asphalt damping sheets and real wool stuffing see what that does.
There was no good/easy way to add bracing but if the damping and wool doesn’t work thats the next thing to try.
Much better, overall I’d consider operation ADS a success 😎
Anyone contemplating rebuilding their ADS crossovers these components work very well !
The rebuilt tweets and mids sound as if new so no regrets on that.
Boxy resonance is still there on male vocals but not as pronounced, is the same with or without the metal grills……I did flip the woofers 180’ as turbo suggested, i’m pretty sure its just the box, gonna try some asphalt damping sheets and real wool stuffing see what that does.
There was no good/easy way to add bracing but if the damping and wool doesn’t work thats the next thing to try.
Much better, overall I’d consider operation ADS a success 😎
This is so ridiculous i’ve got to share it……
So in my endeavors to eliminate this annoying resonance problem (which seems to be this models weak point) I’m sitting here listening and contemplating what the next move is and I look down at the floor where there are two gallons of ‘semi solid’ deck stain on the floor (waiting for a dry stretch to re-seal my upstairs deck) and I think to myself that I’ve seen many people set heavy objects on top their speakers probably for this very reason, simple enough……I get up and place a full can on each speaker (bathroom scale says roughly 11 lbs) and dialed up some of the test tracks that really emphasized the issue (‘Use Me’ by Bill Withers in particular, really makes it obvious) and I gotta say it was rather shocking…….
Not sure if it was just the weight or the non-newtonian properties of paint (or combination of both) but resonance is basically gone! If I focus really hard can still pick it out, but it may be that i’m hearing leftover ghosts!
Remove the cans and it comes right back…..in fact if you rest a hand on the speaker without the can you can feel the resonance, add the can and it disappears into the can which now vibrates at a different level but emits no sound.
Is there any real physics behind this or just a blind squirrel saving rocks thinking they were nuts? 😛
So in my endeavors to eliminate this annoying resonance problem (which seems to be this models weak point) I’m sitting here listening and contemplating what the next move is and I look down at the floor where there are two gallons of ‘semi solid’ deck stain on the floor (waiting for a dry stretch to re-seal my upstairs deck) and I think to myself that I’ve seen many people set heavy objects on top their speakers probably for this very reason, simple enough……I get up and place a full can on each speaker (bathroom scale says roughly 11 lbs) and dialed up some of the test tracks that really emphasized the issue (‘Use Me’ by Bill Withers in particular, really makes it obvious) and I gotta say it was rather shocking…….
Not sure if it was just the weight or the non-newtonian properties of paint (or combination of both) but resonance is basically gone! If I focus really hard can still pick it out, but it may be that i’m hearing leftover ghosts!
Remove the cans and it comes right back…..in fact if you rest a hand on the speaker without the can you can feel the resonance, add the can and it disappears into the can which now vibrates at a different level but emits no sound.
Is there any real physics behind this or just a blind squirrel saving rocks thinking they were nuts? 😛
