Are my tweeters OK?

[Wagner]

A recording's quality is only as good as the speakers will let it reveal.

Mediocre speakers will let a bad recording sound not as bad.

Very revealing speakers will reveal every flaw without mercy.

That said...Control room monitors that are 20+ years old with a foam pad underneath the dome and possible debonding of the voice coil former from the dome can sound scratchy/buzzy at any volume level.

There's only one way to find out.

Any readily available material suitable for refreshing those pieces of foam on an otherwise sound diaphragm?
I always remove the screens and covers on new acquisitions to gently clean (blow away) away the little bits of debris and metallic crud that accumulates due to the magnet. 044s really seem to attract a lot of little crap.
But I don't disturb the diaphragms to clean the gaps on working units because I don't have/know what to put back there if the foam were shot/crumbly.
Do you have a suggestion short of a new diaphragm kit?

Thanks,
Thomas

[jblnut]

I think you need to try a different amp or two before throwing in the towel on the 4412. I've been down this road several times over the years and I finally found nirvana by pairing some classic tube power (Dynaco) with the titanium JBL tweeter. It seems that the almost unlimited high-end of these tweeters is ruthlessly revealing. A lot of solid state amps just sound too bright and edgy - especially when the volume goes up - on certain material. Chaning to tube power totally changed that on my system.

Give the glass bottles a try....

jblnut

[Wagner]

I think you need to try a different amp or two before throwing in the towel on the 4412. I've been down this road several times over the years and I finally found nirvana by pairing some classic tube power (Dynaco) with the titanium JBL tweeter. It seems that the almost unlimited high-end of these tweeters is ruthlessly revealing. A lot of solid state amps just sound too bright and edgy - especially when the volume goes up - on certain material. Chaning to tube power totally changed that on my system.

Give the glass bottles a try....

jblnut

+1

Thomas

[edgewound]

Any readily available material suitable for refreshing those pieces of foam on an otherwise sound diaphragm?
I always remove the screens and covers on new acquisitions to gently clean (blow away) away the little bits of debris and metallic crud that accumulates due to the magnet. 044s really seem to attract a lot of little crap.
But I don't disturb the diaphragms to clean the gaps on working units because I don't have/know what to put back there if the foam were shot/crumbly.
Do you have a suggestion short of a new diaphragm kit?

Thanks,
Thomas

Sweep, disassemble, inspect, clean, replace dampening pad with suitable material, reassemble, sweep again, reinstall.

[Dave Dunbar]

Yep, still following the thread, and weighing all of the information. I appreciate everyone's feedback. I will make the investment to fix the 4412s, once I have determined for sure exactly what is wrong. In an ideal world, I would take them to an experienced shop within a day's drive of Cincinnati to get an expert's read on just what's going on. I suspect the tweeters, but also want to be sure my crossover is good. And, as has been pointed out, a portion of the offending female vocal passages I've noted falls in the domain of the mid driver. Working against me is the fact that I got them from a radio station, which probably fed them with an underpowered amp and which probably had jocks who turned them up to obnoxious levels for sustained periods. I'm sure that didn't help them. On the other hand, on most material, the sound is simply great. Bass is very tight and full, the mids are sweet and detailed. Most highs are fairly nice, if a bit edgy. As I've noted, I actually like a highly-detailed top end. So I'm hoping that they're not totally trashed and in need of crossover repairs or new or repaired mids in addition to the tweeters. If everything's wrong, I'll be in for over $500 for this rescue mission. If it's of any interest, my main amp is a Yamaha CR-2020 receiver (vintage 1977, in flawless shape, and upgraded by Myer-Emco in Wasington with beefier output transistors in 1987, measured at 116w a side at 0.1% distortion) and a top-of-the-line Onkyo CD player produced in 1989 (a super-clean unit, by the way). I also have a Kenwood 7050 receiver (1980, 80 w per side) which sounds particularly nice with the 4412s. My 4412s sit on 4' stands approximately 6' in front of my listening position. I also have a pair of L-110s on my hearth across the room (14' away) which I play at lower level with a different amp and a different EQ curve designed to emphasize intruments one would normally hear at the rear of the sound stage. Works quite well, with the L-110s padded way down so as not to overwhelm the 4412s (this trick requires a fair amount of bass roll-off on the L-110 feed, as they tend to have prodigious bass output). The room is a dedicated sound room with appropriate wall hangings to tame standing waves. At this point, with the exception of what I think is some high end overload that shouldn't be there, I've got a fantastic set-up for the mostly-vintage stuff I listen mostly listen to. Sinatra's right in the room. So are Stan Getz and Dave Brubeck. The Doors, Bert Kaempfert, the Nashville Sound, Elvis...you name it - 95% of it sounds like it was recorded yesterday. Now if I can just tame that high end overload on female vocals, I will have acheived sonic perfection...or as close as I'll come to it.

[jblnut]

Thanks - it makes a lot of sense now. I'm remembering my own JBL journey and you've brought a lot of it back to me.

Asssuming the 4412's are in good working order, you may be experiencing the 4412 shining a microscope (so to speak) into your electronics. It may be the pairing of vintage solid-state Yamaha power with the 4412 is producing the grain/glare/edge you hear. I'd also be a bit suspect of that 1989 CD player. AD/DA circuits have come a *long* way since then and perhaps what you're hearing stems from the CD.

I was using Yamaha power too at one point (I still use it for the low-end of my 250's but no longer the highs) and I ended up going with tubes for exactly the same reasons you are describing.

That's the downside (if it's really a downside) to getting a really good pair of JBLs. You may end up re-thinking most of your other components as you begin to hear things that previous speakers did not reveal. It's all got to add up - speakers + electronincs + room + source material - and that's a lot of variables .

jblnut

[Wagner]

Sweep, disassemble, inspect, clean, replace dampening pad with suitable material, reassemble, sweep again, reinstall.

Thank you!

"Suitable" material, that is the essence of my question.
Other than that which is provided in a new diaphragm kit, what do you suggest that is appropriate? Is there any "over the counter" solution?

Thank you again,
Thomas

[Wagner]

Yep, still following the thread, and weighing all of the information. I appreciate everyone's feedback. I will make the investment to fix the 4412s, once I have determined for sure exactly what is wrong. In an ideal world, I would take them to an experienced shop within a day's drive of Cincinnati to get an expert's read on just what's going on. I suspect the tweeters, but also want to be sure my crossover is good. And, as has been pointed out, a portion of the offending female vocal passages I've noted falls in the domain of the mid driver. Working against me is the fact that I got them from a radio station, which probably fed them with an underpowered amp and which probably had jocks who turned them up to obnoxious levels for sustained periods. I'm sure that didn't help them. On the other hand, on most material, the sound is simply great. Bass is very tight and full, the mids are sweet and detailed. Most highs are fairly nice, if a bit edgy. As I've noted, I actually like a highly-detailed top end. So I'm hoping that they're not totally trashed and in need of crossover repairs or new or repaired mids in addition to the tweeters. If everything's wrong, I'll be in for over $500 for this rescue mission. If it's of any interest, my main amp is a Yamaha CR-2020 receiver (vintage 1977, in flawless shape, and upgraded by Myer-Emco in Wasington with beefier output transistors in 1987, measured at 116w a side at 0.1% distortion) and a top-of-the-line Onkyo CD player produced in 1989 (a super-clean unit, by the way). I also have a Kenwood 7050 receiver (1980, 80 w per side) which sounds particularly nice with the 4412s. My 4412s sit on 4' stands approximately 6' in front of my listening position. I also have a pair of L-110s on my hearth across the room (14' away) which I play at lower level with a different amp and a different EQ curve designed to emphasize intruments one would normally hear at the rear of the sound stage. Works quite well, with the L-110s padded way down so as not to overwhelm the 4412s (this trick requires a fair amount of bass roll-off on the L-110 feed, as they tend to have prodigious bass output). The room is a dedicated sound room with appropriate wall hangings to tame standing waves. At this point, with the exception of what I think is some high end overload that shouldn't be there, I've got a fantastic set-up for the mostly-vintage stuff I listen mostly listen to. Sinatra's right in the room. So are Stan Getz and Dave Brubeck. The Doors, Bert Kaempfert, the Nashville Sound, Elvis...you name it - 95% of it sounds like it was recorded yesterday. Now if I can just tame that high end overload on female vocals, I will have acheived sonic perfection...or as close as I'll come to it.

"I have learned through the experience of ownership that JBL tweeters can be RUTHLESSLY revealing, of both source and material." *

Good luck to you,

Thomas

* (post #8)

[Wagner]

Yep, still following the thread, and weighing all of the information. I appreciate everyone's feedback. I will make the investment to fix the 4412s, once I have determined for sure exactly what is wrong. In an ideal world, I would take them to an experienced shop within a day's drive of Cincinnati to get an expert's read on just what's going on. I suspect the tweeters, but also want to be sure my crossover is good. And, as has been pointed out, a portion of the offending female vocal passages I've noted falls in the domain of the mid driver. Working against me is the fact that I got them from a radio station, which probably fed them with an underpowered amp and which probably had jocks who turned them up to obnoxious levels for sustained periods. I'm sure that didn't help them. On the other hand, on most material, the sound is simply great. Bass is very tight and full, the mids are sweet and detailed. Most highs are fairly nice, if a bit edgy. As I've noted, I actually like a highly-detailed top end. So I'm hoping that they're not totally trashed and in need of crossover repairs or new or repaired mids in addition to the tweeters. If everything's wrong, I'll be in for over $500 for this rescue mission. If it's of any interest, my main amp is a Yamaha CR-2020 receiver (vintage 1977, in flawless shape, and upgraded by Myer-Emco in Wasington with beefier output transistors in 1987, measured at 116w a side at 0.1% distortion) and a top-of-the-line Onkyo CD player produced in 1989 (a super-clean unit, by the way). I also have a Kenwood 7050 receiver (1980, 80 w per side) which sounds particularly nice with the 4412s. My 4412s sit on 4' stands approximately 6' in front of my listening position. I also have a pair of L-110s on my hearth across the room (14' away) which I play at lower level with a different amp and a different EQ curve designed to emphasize intruments one would normally hear at the rear of the sound stage. Works quite well, with the L-110s padded way down so as not to overwhelm the 4412s (this trick requires a fair amount of bass roll-off on the L-110 feed, as they tend to have prodigious bass output). The room is a dedicated sound room with appropriate wall hangings to tame standing waves. At this point, with the exception of what I think is some high end overload that shouldn't be there, I've got a fantastic set-up for the mostly-vintage stuff I listen mostly listen to. Sinatra's right in the room. So are Stan Getz and Dave Brubeck. The Doors, Bert Kaempfert, the Nashville Sound, Elvis...you name it - 95% of it sounds like it was recorded yesterday. Now if I can just tame that high end overload on female vocals, I will have acheived sonic perfection...or as close as I'll come to it.

You should check for DC on your speaker taps. Anything over 50mV or so and you may have found your problem.
This was a TOTL receiver, but it's still more than 30 years old.
I don't have a schematic handy and don't know if Yamaha had a pot for adjusting offset or if they used differential pairs like Kenwood.
I'll bet a dollar the DC on your outputs is over 50mV. (presuming you haven't had it re-capped and the power boards adjusted)

Thomas

[Mr. Widget]

Asssuming the 4412's are in good working order, you may be experiencing the 4412 shining a microscope (so to speak) into your electronics. It may be the pairing of vintage solid-state Yamaha power with the 4412 is producing the grain/glare/edge you hear. I'd also be a bit suspect of that 1989 CD player. AD/DA circuits have come a *long* way since then and perhaps what you're hearing stems from the CD.

I agree 100% however...

My serious dissatisfaction of late came when I had a chance to audition a new set of Acoutic Energy speakers, which have a VERY forward characteristic like the JBLs, but with none of the high end harshness/overload I'm hearing on my 4412s.

Were these speakers in your usual listening room with the same electronics?


Widget

[Wagner]

Yep, still following the thread, and weighing all of the information. I appreciate everyone's feedback. I will make the investment to fix the 4412s, once I have determined for sure exactly what is wrong. In an ideal world, I would take them to an experienced shop within a day's drive of Cincinnati to get an expert's read on just what's going on. I suspect the tweeters, but also want to be sure my crossover is good. And, as has been pointed out, a portion of the offending female vocal passages I've noted falls in the domain of the mid driver. Working against me is the fact that I got them from a radio station, which probably fed them with an underpowered amp and which probably had jocks who turned them up to obnoxious levels for sustained periods. I'm sure that didn't help them. On the other hand, on most material, the sound is simply great. Bass is very tight and full, the mids are sweet and detailed. Most highs are fairly nice, if a bit edgy. As I've noted, I actually like a highly-detailed top end. So I'm hoping that they're not totally trashed and in need of crossover repairs or new or repaired mids in addition to the tweeters. If everything's wrong, I'll be in for over $500 for this rescue mission. If it's of any interest, my main amp is a Yamaha CR-2020 receiver (vintage 1977, in flawless shape, and upgraded by Myer-Emco in Wasington with beefier output transistors in 1987, measured at 116w a side at 0.1% distortion) and a top-of-the-line Onkyo CD player produced in 1989 (a super-clean unit, by the way). I also have a Kenwood 7050 receiver (1980, 80 w per side) which sounds particularly nice with the 4412s. My 4412s sit on 4' stands approximately 6' in front of my listening position. I also have a pair of L-110s on my hearth across the room (14' away) which I play at lower level with a different amp and a different EQ curve designed to emphasize intruments one would normally hear at the rear of the sound stage. Works quite well, with the L-110s padded way down so as not to overwhelm the 4412s (this trick requires a fair amount of bass roll-off on the L-110 feed, as they tend to have prodigious bass output). The room is a dedicated sound room with appropriate wall hangings to tame standing waves. At this point, with the exception of what I think is some high end overload that shouldn't be there, I've got a fantastic set-up for the mostly-vintage stuff I listen mostly listen to. Sinatra's right in the room. So are Stan Getz and Dave Brubeck. The Doors, Bert Kaempfert, the Nashville Sound, Elvis...you name it - 95% of it sounds like it was recorded yesterday. Now if I can just tame that high end overload on female vocals, I will have acheived sonic perfection...or as close as I'll come to it.

I would also suggest with a CD player of this vintage that you lift the muting transistors and replace the output blocking caps (easy, and only costs a few bucks) at minimum. Use film a type, although a good audio grade bi-polar electrolytic will work but they're harder to find.
Players from this time are not known for being very "smooth".

Thomas

[jim3860]

Dave this is my oppinion after having owned several JBL's with the 035ti and 035ti-a tweeter they are shrill as hell to my ears and there isnt a lot you can do IMHO to change that if your ears are able to hear into the upper frequencies then most likely you will suffer listening fatigue after a few hours or even less. If you use a tube pre amp or amp and even a tube buffer throw in some warm or dark sounding IC's and you could take the edge off and they may well be fine then.


I am not sure if you would be able to find a silk dome or paper drop in, I kinda doubt it perhaps you could even get a seperate tweeter that sits atop the 4312 to use not sure. Or you could simply sell them and get JBL's that uses a paper tweeter or something similar if you like the sound of the bass and midrange of your JBL's.

The good thing is JBL made all different kinds of speakers for all different types of listening prefernces and you should be able to find what you like with a little listening and research.

REGARDS JIM

[JBL 4645]

Do those tweets (035Ti-something-or-other-?) have a foam under the dome that's turned to goo ?
Just a WAG

Sounds like Ferrofluid.

http://en.wikipedia.org/wiki/Ferrofluid

Ferrofluids are commonly used in loudspeakers to remove heat from the voice coil, and to passively damp the movement of the cone. They reside in what would normally be the air gap around the voice coil, held in place by the speaker's magnet. Since ferrofluids are paramagnetic, they obey Curie's law, thus become less magnetic at higher temperatures. A strong magnet placed near the voice coil (which produces heat) will attract cold ferrofluid more than hot ferrofluid thus forcing the heated ferrofluid away from the electric voice coil and toward a heat sink. This is an efficient cooling method which requires no additional energy input.[6]

[JeffW]

Foam under the tweeter dome doesn't sound at all like ferrofluid to me.

Sounds like foam. Looks like foam, too.

[BJL]

When I wrote my earlier comment I meant this foam which might get sticky when it deteriorates.

-Mallwalker