LSIM speaker troubleshooting

musicmatters

Hello

Greetings.
I recently bought a pair of LSIM 707 & 706 speaker from Adorama. All the packages were double boxed and none of them had any visible shipping damage and all were new.

I am using Marantz SR7012 as pre-amp & Rotel RMB-1555 amplifier and use 3 channel for HT & 2 ch for music. Mostly i use netflix for movies and wav/flac files for music.

The issue I am having is that, at mid/high frequencies, I can hear distortion from all the speakers, especially with female vocals and high pitched instruments. I am listening to music at low to moderate volume. All the speakers are absolutely silent when there is no music; so i guess i can eliminate amplifier noise/ground loop/power supply hum issues.

I request all the experienced members and Polk technical team of this forum to help me troubleshoot and isolate the cause of the distortion and make sure that none of the speakers/drivers are defective.

Thank you very much

Emlyn

One thing is to try pressing all around the rubber like material around the drivers a little to firmly seat them if they shook loose in shipment. That material is removable to get at the driver screws underneath. The screws are most likely not loose, but easy enough to check to be sure.

Next step could be to just run the speakers using the receiver to see if that makes any difference.

jeremymarcinko

I’d start by power cycling the Marantz then re run the auto calibration.

myhikingboots

I recently purchased a pair of 707s, a pair of 703's and a 706 from the Adorama sale. The UPS driver dropped one of the 703's and even though it was double boxed, the weight of the magnet in the woofer caused it to rip through the cone. I had a replacement from Adorama in a week. Having said this, it seems remote that all three of your speakers would be defective. I'm running mine (for now) with a Marantz avr and have not heard anything like the distortion you described, in fact they are absolutely sublime. Have you tried the different modes in the preamp, like "music", "movie" or "pure/direct" ?
It's got to be in your setup somewhere. I hope you figure it out soon.

vavan

musicmatters wrote: »

The issue I am having is that, at mid/high frequencies, I can hear distortion from all the speakers, especially with female vocals and high pitched instruments

could you measure it using REW?

tonyb

Do you hear that same distortion when watching movies ?

F1nut

Defective tweeters.

musicmatters

Thanks a lot for all your suggestions. I feel more confident now that I can figure out the issues.

I already tried connecting speakers from receiver directly; the distortion was still there and I felt the sound lacked clarity and was dull.

Let me do try all the other suggestions and will post the findings.

One question is that whether the amplifier is not powerful enough (rated 125W per channel @8 ohms) for these speakers.

Nightfall

musicmatters wrote: »

One question is that whether the amplifier is not powerful enough (rated 125W per channel @8 ohms) for these speakers.

Not powerful enough to get the most out of them, definitely. Not powerful enough as to cause distortion at any volume, definitely not.

musicmatters

tonyb wrote: »

Do you hear that same distortion when watching movies ?

Not so much; its more prominent while playing music.

musicmatters

F1nut wrote: »

Defective tweeters.

I cannot distinguish whether its tweeter or midrange; maybe using REW might be the absolute best to figure it out.

musicmatters

vavan wrote: »

musicmatters wrote: »

The issue I am having is that, at mid/high frequencies, I can hear distortion from all the speakers, especially with female vocals and high pitched instruments

could you measure it using REW?

Shall i use the test tomes from REW or do you have any other suggestions?
Thanks

jeremymarcinko

Any chance you drove that amp into clipping at some point and damaged the tweeters and/or crossovers?

F1nut

There's been a problem with the tweeters of late. Use a paper towel roll to isolate the tweeter.

vavan

musicmatters wrote: »

Shall i use the test tomes from REW or do you have any other suggestions?
Thanks

just do standard sweep and see distortion tab in rew

Offn

F1nut wrote: »

There's been a problem with the tweeters of late. Use a paper towel roll to isolate the tweeter.

I'm also having distortion in some situations on the new speakers.
I've not had much time and room right now to deal with auditioning and placement.

What does this mean with tweeter problems of late?
I've kept my white substance 707s and 706c
I had a falling down grate on one and bent on the other and some issue with one or two 6x9
Polk sent two new grates and two new 6x9

I ordered two pair 703 another 706 and a pair of 702 which have come and so far I've only checked to see the inside of the 703 were labeled cherry have not opened.

SO --- right now I've only the two 707 hooked up and I pop back on to forum because I'm trying to figure out a problem I've noticed and have further narrowed.

Problems on certain highs I'm getting some vibrating/buzzing distortion from what appears to be the top of the one (on right - though I did switch right left speaker cables which yielded distortion on same physical speaker with the left channel) 707. I have not figured out tweeter or mid yet - will try with the paper towel center - certainly seems like tweet.
I went through frequency sweeps and didn't notice the distortion when going up to
22Khz but then it's very noticible on certain songs.
Example
https://www.youtube.com/watch?v=zfaOf70M4xs&list=RDzfaOf70M4xs&start_radio=1

I'm in/was in? same boat as op trying to figure out if it was the audio and equipment sources. Today trying to figure out more and with likes of above video - rather sure it's 100 bad tweet/mid on the one. This worries me about the 706 which seemed overly harsh when I was trying thought I disconnected and put away for later when area will be ready for speakers. Now I'm worried I've gotta figure out if that has a bad tweeter/mid also. And I was going to just make sure the 703/706/702s Seemed OK but seems like I'm going to have to worry about same issue with all those immediately.

Guess I'm probably going to have to call Polk yet again and request replacement for the one speaker? See how it goes?

UGH, I don't have the time and energy to worry about all this - I just wanted some good speakers again after so very long of having tolerable stuff.
It's meant to relax and enjoy - not stress and rip my hair out over.

Offn

I don't know if I should be hijacking this post as sounds like same issue and it was right there when I got on forum - or creating my own problem post.

F1nut

What does this mean with tweeter problems of late?

Distortion/buzzing.

DaveHo

Not a new problem. Had the same issue (3?) years back with my 705s. Polk replaced the pair. Inexcusable in a TOTL speaker, but it was taken care of.

pawelmwo

I'm no expert and not sure this will help you at all but my center channel had distortion when I was just using my receiver (Denon x4400h rated at 125 per channel in stereo) running with two Polk 705's and a 706c. I purchased 3 Outlaw 2200 amps which are rated 200 watt per channel at 8 ohms and used the pre-outs on my receiver using ECO mode to reduce the AVR power draw. All the distortion is gone now and I can crank the volume beyond 0 and don't hear crackling or buzzing. I didn't really spend much time to rule out something wrong with the receiver as I found a great deal on the amps. I guess I should test that a bit more before the warranty expires.

Offn

I can't say about a high power amp
I've further investigated my problems
I have a Yamaha htr-5650
Sony str-dn1030
Sony str-dn1080
Yamaha tsr-7850
I thought a couple others were safe in back of storage when I had a theft many years ago but just got to where old Marantz was and its gone.

So 707 I have 2 one has horrible crackling other seems like it's fine probably
When I plug the one into left channel or right channel the same one has the crackling this would indicate speaker not avr.
I've tried one 706 which seems to also be distorting I've tried in center right and left and same.
Not had much time or space though just tonight I've tried 2 703 and one is horrible and Its both tweet and mid. Again changing left to right yields distortion on the one speaker

Pachelbel Canon in d - highest frequency strings trigger like crazy

I have only tried one or two speakers plugged in at a time except for a few seconds with 2 707 and the 706 on str-1080.

I have two 707 four 703 pair 702 and two 706
Have only tried 707 one 706 and two 703 so far and seem to have over 50percent failure. I haven't turned up loud enough to identify is there is a bare minimum issue with the so far presumed good 1 707 and 1 703 and I somewhat think I'm hearing distortion is the second 707.

K_M

Offn wrote: »

I can't say about a high power amp
I've further investigated my problems
I have a Yamaha htr-5650
Sony str-dn1030
Sony str-dn1080
Yamaha tsr-7850
I thought a couple others were safe in back of storage when I had a theft many years ago but just got to where old Marantz was and its gone.

So 707 I have 2 one has horrible crackling other seems like it's fine probably
When I plug the one into left channel or right channel the same one has the crackling this would indicate speaker not avr.
I've tried one 706 which seems to also be distorting I've tried in center right and left and same.
Not had much time or space though just tonight I've tried 2 703 and one is horrible and Its both tweet and mid. Again changing left to right yields distortion on the one speaker

Pachelbel Canon in d - highest frequency strings trigger like crazy

I have only tried one or two speakers plugged in at a time except for a few seconds with 2 707 and the 706 on str-1080.

I have two 707 four 703 pair 702 and two 706
Have only tried 707 one 706 and two 703 so far and seem to have over 50percent failure. I haven't turned up loud enough to identify is there is a bare minimum issue with the so far presumed good 1 707 and 1 703 and I somewhat think I'm hearing distortion is the second 707.

Are the distortions you hear, at fairly normal listening volumes?

Offn

K_M wrote: »

Are the distortions you hear, at fairly normal listening volumes?

I replied it posted to forum then edited to fix an incorrect word and post disappeared.
So I reply again.

Low to low normal.
The 703 using for first time last night in a small bedroom/office I turned them to where the sound could just barely be heard on other side of closed door and then just a little louder isolating. Could distinctly hear the distortion on the mid and tweeter on one speaker. Other I wasn't sure about as I thought I heard a crackle a couple times but I had both plugged in and could have been from the bad one.

The 707s once I knew the types of tones that were causing the issue.... and I found last night the Canon in D was very good at bringing it out on the highest violin notes - at least on the 703s haven't tried on 707s or 706 yet... On 707s Could hear turned to just a whisper all the way up to moderately loud.
As low normal moderate or high are all subjective - here moderate high being they are near the front door and window in living room and can't really hear them at all more than 5 feet away from window outside.
To put in perspective I've played my yamaha ns-777 and seperately my sony ssha1 (bookshelf) and old Acoustic research old fischer and several others at not close to max volume and can hear them 90' plus away across the street on same avrs (yamaha 7850 and sony 1080 in living room.)

K_M

Offn wrote: »

K_M wrote: »

Are the distortions you hear, at fairly normal listening volumes?

I replied it posted to forum then edited to fix an incorrect word and post disappeared.
So I reply again.

Low to low normal.
The 703 using for first time last night in a small bedroom/office I turned them to where the sound could just barely be heard on other side of closed door and then just a little louder isolating. Could distinctly hear the distortion on the mid and tweeter on one speaker. Other I wasn't sure about as I thought I heard a crackle a couple times but I had both plugged in and could have been from the bad one.

The 707s once I knew the types of tones that were causing the issue.... and I found last night the Canon in D was very good at bringing it out on the highest violin notes - at least on the 703s haven't tried on 707s or 706 yet... On 707s Could hear turned to just a whisper all the way up to moderately loud.
As low normal moderate or high are all subjective - here moderate high being they are near the front door and window in living room and can't really hear them at all more than 5 feet away from window outside.
To put in perspective I've played my yamaha ns-777 and seperately my sony ssha1 (bookshelf) and old Acoustic research old fischer and several others at not close to max volume and can hear them 90' plus away across the street on same avrs (yamaha 7850 and sony 1080 in living room.)

We have had a few similar issues (not on Lsim) but found computer generated tones, where you can move through every frequency, usually will bring out the offending tone right to the exact frequency.

Found that lightly touching the tweeter dome at various points, with a cotton swab would reduce the distortion and realized it was a manufacturing issue, where something was rubbing or loose in driver itself, or found that banging on speaker enclosure was making distortion rise and fall, and it was poor connection issues with old crossover components.

Yours being new sounds like the Lsim tweeter issue several have found of course. But was curious as to the level that brought it out.
Thanks

Offn

.

Offn

.

Offn

Thought my repost had also vanished - I don't know what happened I couldn't see it. I see it now. Original still not there.

I did frequency sweeps to limited extent on the 707s and didn't notice the distortion.
crackles like crazy for certain songs though
highest notes here:
https://www.youtube.com/watch?v=jJRdLZyOU4w

I'd do a linked time url but I'm not at the 703s now to play
crackles like crazy many times in the song though.

pitdogg2

yea for sure nothing there should be a problem unless you got it on 12. Call Polk CS start the process for new tweeters.

vavan

I had similar problem with my lsim 705 sounding harsh and edgy on some material (distortion graph posted in other thread) though not sure whether tweeter or something else was the culprit as poor servicemen couldn't pinpoint the problem so I ended up returning those and got away with revel f208

K_M

vavan wrote: »

I had similar problem with my lsim 705 sounding harsh and edgy on some material (distortion graph posted in other thread) though not sure whether tweeter or something else was the culprit as poor servicemen couldn't pinpoint the problem so I ended up returning those and got away with revel f208

https://www.stereophile.com/content/revel-performa3-f208-loudspeaker-measurements

The Revel are praised highly. How do you like them ?(assuming you have them already)

vavan

K_M wrote: »

How do you like them ?

see this and few following posts
but lsim offers much more convenient spikes