|
|
|
01-13-2023, 07:32 PM
|
#1
|
Human being with feelings
Join Date: Sep 2011
Location: PNW, USA
Posts: 698
|
Shot in the dark: Know how to fix a tweeter?
Shot in the dark, or a long shot, I know, but figured I'd run this by the Reaper forum wisdom...
I bought some Presonus Eris XT5 monitors 2 1/2 years ago, one of them has always had a tweeter that drops out. I read-up on that at the Presonus support website, and there was quite a few people reporting the same or similar problems. One 'fix' was to check for a couple particular bad solder joints. I thought that's what my problem ended up being, I re-soldered those joints, and it seemed to work. For a while? Or maybe it was luck or something. Flash forward to now and my tweeter drops out more often and stays dropped out longer...
The second 'fix', or rather diagnosis, was that some of these shipped with "lazy" tweeters. That's exactly what I'd call my problem, a lazy tweeter. It will drop out, and then if I crank the gain up it will come back in - until it drops out again. It drops out randomly, maybe a dozen times over a few hour period.
So, that's where I'm at. I don't want to contact Presonus again (I did that right when I noticed the problem, but the process was bad, I didn't want to send the monitor back and pay $40 shipping, be without monitors for a few weeks, etc.). I don't want to buy different monitors at the moment.
So I'm thinking maybe there's some straight forward way to fix the tweeter? What could the problem be? If I pull the tweeter out is there something I'd actually be able to see that's wrong, or maybe test it somehow? I did look at it before, when I had the thing opened, didn't notice anything untoward, no loose wires, bad connections...
Anyway, figured it'd be worth a shot, posting here. Any insights greatly appreciated...
edit: here's a link to a thread I started back when I had the problem, where I talk about it more. I'll have to review that myself: https://forum.cockos.com/showthread....light=presonus
edit2: OK, well, I reviewed my earlier thread and I guess I've been here before. I had already taken the tweeter out and looked to see 'what' could be fixed, if anything. Here's a link to where I mentioned that, with pics of the tweeter (same thread as above link, only down a ways): https://forum.cockos.com/showpost.ph...1&postcount=22
Last edited by eq1; 01-13-2023 at 08:02 PM.
|
|
|
01-13-2023, 07:44 PM
|
#2
|
Human being with feelings
Join Date: Jul 2021
Location: Swiss Zürich
Posts: 846
|
thomann
can you post a photo or video of this popping out tweeter ?
If it needs to get replaced and you can do it by yourself then ask Thomann for a spare tweeter.
Thomann has a huge sortiment of spare parts. Not easy to find it online, I would contact them via email.
|
|
|
01-13-2023, 08:09 PM
|
#3
|
Human being with feelings
Join Date: Sep 2011
Location: PNW, USA
Posts: 698
|
I added a second edit to my original post, before I saw yours. That edit has a link to images of the tweeter. Thanks for the Thomann suggestion, I'll look into that.
|
|
|
01-14-2023, 04:21 AM
|
#4
|
Human being with feelings
Join Date: Jun 2011
Location: Belgium
Posts: 5,246
|
One fault I've seen with tweeters, just not as often as with the Presonus ones, is that the points where the coil wire attaches to the connection plug break. This often gives an intermittent connection.
To check that with this particular tweeter, you'd need to scrape the black goo off from the front of the connection points. That needs to be done very cautiously, as the coil wires are very thin.
If you can see the disconnection (probably need a magnifying glass), it's easy enough to solder in a small/thin piece of wire to bridge the gap after the complete removal of the goo.
I hate that black goo, as it stops being an isolator in humid weather. I've had several KRKs on the bench that exhibited all kinds of strange behaviour because the goo started going conductive. However, I've never seen this goo causing the problem on speakers, just on electronic boards.
It's not a real short, so it shouldn't matter on speakers, but the conductance is enough to cause electronics to go haywire. It usually starts with the speaker becoming noisy.
I hope your tweeter has this kind of defect, as it' easy and cheap to repair. Good luck!
It could very well be a quality control problem with the goo, as I've seen this used all over, usually not producing any problem at all.
__________________
In a time of deceit telling the truth is a revolutionary act.
George Orwell
|
|
|
01-14-2023, 06:07 AM
|
#5
|
Human being with feelings
Join Date: Jul 2010
Location: Silicon Valley, CA
Posts: 2,787
|
Quote:
It will drop out, and then if I crank the gain up it will come back in - until it drops out again.
|
I've had that happen a couple of times in various "things". It's usually been a bad plug-in connection or a bad switch contact. ...Probably corrosion where higher voltage can "blow-through" the corrosion, temporarily fixing it.
Contact cleaner can often fix a switch and simply unplugging and re-plugging the connector sometimes fixes a flakey plug-in connection and/or contact cleaner or scraping the contacts with a knife, etc.
Quote:
If I pull the tweeter out...
|
If you swap the tweeters around with the other speaker that will tell you if it's the tweeter itself or something else in the electronics or connections.
And you can try flexing the board and/or tapping on it with the back of a screwdriver or something.
Sometimes surface mount components can have unsoldered pins and it will work as long as it's touching the circuit board. That can be hard to see because it will look soldered. Where I we have those one-ended wood Q-Tips on-hand and I use the wood-end to drag-across the contacts of surface mount IC while power is on to see if goes good/bad. Or with power off I try to see if I can wiggle the pins one at a time with an X-acto knife.
If there is a flakey/cracked trace or via on the circuit board it can be hard to find & fix. Sometimes you can duplicate-bypass the connection with a wire (usually 30 AWG "wire wrap" wire) but with high-density boards or with a via that goes to the other side of board, that can be difficult.
|
|
|
01-14-2023, 07:43 PM
|
#6
|
Human being with feelings
Join Date: Sep 2011
Location: PNW, USA
Posts: 698
|
Thanks guys, a lot of good suggestions...
Quote:
Originally Posted by cyrano
One fault I've seen with tweeters, just not as often as with the Presonus ones, is that the points where the coil wire attaches to the connection plug break. This often gives an intermittent connection.
To check that with this particular tweeter, you'd need to scrape the black goo off...
|
Yeah, that's about the conclusion I came to after re-reading what I wrote in that other thread - that I'd have to scrape the goo off and try to inspect the wire connections. I might try that, maybe after I source a replacement tweeter (I did open a 'ticket' at Presonus, asking if they have replacements). Or I might just try it in any case, not too much to lose, I'll probably buy new, different monitors in not-too-distant future.
Quote:
Originally Posted by DVDdoug
If you swap the tweeters around with the other speaker that will tell you if it's the tweeter itself or something else in the electronics or connections.
|
Great idea. Though I'm somewhat reluctant to pop open the one that actually works. As I recall there's a semi-seal holding the back panel on, and then maybe some other stuff has to be removed in order to get some working room to get to the tweeter/to get it out. So not totally painless. But, I may try it, I may have to. I'm pretty sure it's the tweeter itself, but I'm not totally sure...
|
|
|
03-08-2023, 11:26 PM
|
#7
|
Human being with feelings
Join Date: Sep 2011
Location: PNW, USA
Posts: 698
|
I know everyone's been waiting with baited breath for the outcome of this saga...
I finally got a replacement tweeter today. It's taken me this long, working through PreSonus and then Fender (who bought PreSonus at some point and handles this stuff). Pretty ridiculous process. I paid like $7 each + shipping for two tweeters. Took me all of 15 minutes or so to do the replacement, and, it seems to be fixed. I haven't used it much at this point but haven't heard a drop out yet, I usually would have by now... So, I'll give it a few days before I declare victory...
If it does end up dropping out again I'll likely be able to try replacement electronics (amp and stuff) - at one point they sent me two replacement rear panels by mistake. They're for the Eris E5 not E5XT, the layout on the back is a little different than what I got, but the innards look the same, same version number on at least one of the boards. Hopefully I won't need them though.
|
|
|
03-09-2023, 03:22 AM
|
#8
|
Human being with feelings
Join Date: Nov 2017
Posts: 1,586
|
Quote:
Originally Posted by eq1
... I haven't used it much at this point but haven't heard a drop out yet, ...
|
If there are still failures or drop-outs - you never know -
then maybe it could be the Heatless Tankwater?
Cases are known where an inductive voltage from Heatless
Tankwaters can produce such dropouts. Or maybe a Waterless
Heat-tanker?
|
|
|
03-28-2023, 07:29 PM
|
#9
|
Human being with feelings
Join Date: Sep 2011
Location: PNW, USA
Posts: 698
|
Figured I'd update with a couple tips in case someone with similar problem comes across this thread.
First, haven't heard drop out, so looks like 'bad tweeter' was indeed the problem. If you can stomach the process, trying to get replacement tweeter from PreSonus/Fender seems the way to go.
I did try to 'open up' the bad tweeter and see if there was an obvious, fixable problem. Short answer is "no." It's actually not too hard to 'open up'...
I began by carefully scraping off the "black goo" from the terminals, as cyrano mentioned earlier. Not much to see there, blobs of solder, wires not visible/not accessible. I didn't see any breaks or anything wrong there.
Then I pried off the 'silk dome'. If I was more careful I probably could have gotten that off without damaging it, the 'lip' isn't sealed down very strongly. As it was, I think I poked a hole in it. If I was more careful getting it started I could have pulled it off cleanly. Once that lip is unsealed, the whole innards are exposed; the voice coil will only be attached to the body by two tiny wires (so you can't pull the whole thing apart without breaking those wires)... I didn't see any breaks or bad connections with those two wires, on the terminal side or the 'voice coil' side, though it's hard to tell on the voice coil side, the wires attached there are ensconced in some kind of clear-ish glue or something.
That's about it with the disassembly. I could take pics and post if anyone were ever interested. But this is mostly academic, there doesn't seem to be any easy, expedient way to 'fix' it, though the right, dedicated person surely could.
Other than that, just wanted to point out that there's some good explanations of "loud speaker" basics, design, diagrams, etc. in the Yamaha "Sound Reinforcement Handbook." I've had one of those laying around for a while, picked it up the other day and came across that section.
There's a little table that lists common manufacturing defects, for example, it says this:
"Defect: Cold solder joints at coil lead-in wires. Test: DC resistance of voice coil connection. Result: Coil resistance greater than rated impedance of driver, or infinite." And this,
"Defect: Faulty welds at the voice coil terminations on the coil former. Test: DC resistance of voice coil connection. Result: coil resistance infinite or intermittent; sound ceases or is full of static."
This latter one kind of sounds like my problem... Lots of useful stuff in this handbook.
hmm, well, I did take a pic, but my card reader seems to be faulty.
|
|
|
Thread Tools |
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -7. The time now is 03:14 PM.
|