Another LSiM705 tweeter distorting
pyrocyborg
Posts: 524
Hi!
In May, I bought two brand new LSiM705 for stereo listening (music and movies). Right out the box, there were a problem with the left channel tweeter, but I couldn't pin-point it until I heard solo piano and some women's voice in movies, what I first assumed was bad mixing and poor quality audio in Netflix (for movies). But then, after few days of listening, I could hear it on some other tracks or pieces (FLAC), and on DTS bluray audio track, so I thought there were a problem with the speaker. I swapped the left and right speaker to see if the "issue" was with the speaker or the electronics and it seemed that the LSiM was the culprit. I started a thread on these very forums and someone mentionned that there were some cases of blown LSiM tweeters.
I exchanged the speaker for another one and connected it as the right channel speaker on my amplifier. It seemed that this new one was allright, even if I could hear a slight distorsion in some rare occasions which I assumed, another time, that it was poor audio quality from standard quality Netflix. I couldn't hear it except sometime in movies when people spoke (even with DTS track): there were a slight distorsion, but not too often and far less than the other speaker did in the same conditions. Annoying, but nothing to be too concerned about. For music, it was more than adequate so I didn't make a case.
Yesterday, I moved the speakers in another (smaller and closed 120 sq ft) room. I went from a 9 feet listening distance to 6 feet listening distance. While the room is far from perfect with reverb and all (being non treated), I can clearly hear a distorsion coming from the "new" speaker. Again, it follows the speaker when I swap cables.
I know my amplifier isn't beefy (50w integrated amplifier), but there is no way I am underpowering these speakers, especially when I'm listening at volume levels lower than 80 dB with occasionnal peaks at 85 dB in movies which would require 1 to 5w, tops (can't go any higher with my tinnitus). Given my amplifier has a certain headroom, I wouldn't be too concerned with the lack of power. I doubt I "misused" or abused the speakers in any way as I baby them.
Also, every LSiM705 I owned (the first one, which I returned; this one and the "perfect condition" one) are from the same batch. Only one of them have no distorsion issue right out the box and will probably do just fine. Is it possible that there were some QC issue with that particular batch?
I had no trouble with any of my previous Polk speakers (6 pairs, RTi and LSi) over the years and they're still working fine. Could I be unlucky enough to have two defective speakers out of three, or is there something else causing this?
In May, I bought two brand new LSiM705 for stereo listening (music and movies). Right out the box, there were a problem with the left channel tweeter, but I couldn't pin-point it until I heard solo piano and some women's voice in movies, what I first assumed was bad mixing and poor quality audio in Netflix (for movies). But then, after few days of listening, I could hear it on some other tracks or pieces (FLAC), and on DTS bluray audio track, so I thought there were a problem with the speaker. I swapped the left and right speaker to see if the "issue" was with the speaker or the electronics and it seemed that the LSiM was the culprit. I started a thread on these very forums and someone mentionned that there were some cases of blown LSiM tweeters.
I exchanged the speaker for another one and connected it as the right channel speaker on my amplifier. It seemed that this new one was allright, even if I could hear a slight distorsion in some rare occasions which I assumed, another time, that it was poor audio quality from standard quality Netflix. I couldn't hear it except sometime in movies when people spoke (even with DTS track): there were a slight distorsion, but not too often and far less than the other speaker did in the same conditions. Annoying, but nothing to be too concerned about. For music, it was more than adequate so I didn't make a case.
Yesterday, I moved the speakers in another (smaller and closed 120 sq ft) room. I went from a 9 feet listening distance to 6 feet listening distance. While the room is far from perfect with reverb and all (being non treated), I can clearly hear a distorsion coming from the "new" speaker. Again, it follows the speaker when I swap cables.
I know my amplifier isn't beefy (50w integrated amplifier), but there is no way I am underpowering these speakers, especially when I'm listening at volume levels lower than 80 dB with occasionnal peaks at 85 dB in movies which would require 1 to 5w, tops (can't go any higher with my tinnitus). Given my amplifier has a certain headroom, I wouldn't be too concerned with the lack of power. I doubt I "misused" or abused the speakers in any way as I baby them.
Also, every LSiM705 I owned (the first one, which I returned; this one and the "perfect condition" one) are from the same batch. Only one of them have no distorsion issue right out the box and will probably do just fine. Is it possible that there were some QC issue with that particular batch?
I had no trouble with any of my previous Polk speakers (6 pairs, RTi and LSi) over the years and they're still working fine. Could I be unlucky enough to have two defective speakers out of three, or is there something else causing this?
Speakers: Polk Audio LSiM 705, LSiM 703, LSiM 704c
Receiver: Denon X3500H
Receiver: Denon X3500H
Post edited by pyrocyborg on
Comments
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Contact Polk Customer Service for a replacement tweeter. I'm sure they would like to know about the situation and would want to test the tweeter in question.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
It's unlikely, but possible that you have recieved several defective speakers. Can you borrow a friend's amp and front end just to rule out defects upstream?"Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
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I will contact CS and test with another amplifier/DAC in the meantime.
It's driving me crazy by the way... :SSpeakers: Polk Audio LSiM 705, LSiM 703, LSiM 704c
Receiver: Denon X3500H -
Well... Seems like it was only the "Headphones" DSP option that was activated on JRiver that might have caused this. I sometime heard that kind of distorsion while using my speakers because I connect my headphones for late night listening and put that option on (and sometimes forget to turn it off).
Guess I wasn't unlucky enough to get two defective speakers...
To be honest, after hearing that the "distorsion" sound was here when using headphones, I ruled the speakers out of the equation. I was sure that either my amplifier or my DAC were dying.
Case solved! Thanks for your answers, I'll keep them in mind, just in case.Speakers: Polk Audio LSiM 705, LSiM 703, LSiM 704c
Receiver: Denon X3500H -
Glad to see you solved the issue. Just for future reference, it's distortion.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
PFFFT user error...:cheesygrin:
Yeah.... I think I won't use that "option" anymore. I mean, what kind of "improvement" creates distortion and cracking noise? :PSpeakers: Polk Audio LSiM 705, LSiM 703, LSiM 704c
Receiver: Denon X3500H -
Glad to see you solved the issue. Just for future reference, it's distortion.
Noted...
P-S: It's kinda hard to write correctly in english when a word like distorsion (in french) is almost the same in english. I mean, for us (and I don't know if it's the same for you), "sion" in french sounds like "tion" in english, so I get both mixed up from time to time... :PSpeakers: Polk Audio LSiM 705, LSiM 703, LSiM 704c
Receiver: Denon X3500H -
Yeah, they sound the same.
Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk
