LSiM 705 have arrived

Clipdat

Excuse my ignorance, which graph is for which speaker?

shs

The top graph is the "bad" left speaker and with a ~250 Hz signal, you can see the harmonics at 500 and 750 Hz are only 20-30 dB down and there is lots of hash at higher frequencies. With the "good" right speaker, bottom, you don't see any obvious harmonics. This was all done with my phone and used to show Polk the nature of the distortions.

Clipdat

Thanks again for the clarification, I sincerely appreciate it.

What did that distortion sound like when you were playing music? Was it obvious?

shs

The answer to your last question is, yes and no. With music, it depends and only happened when there was fairly strong content in the mid-bass frequency range. Also, this type of harmonic distortion is often done on purpose, e.g. “fuzz” with electric guitars, and in the colloquial, sort of sounds like farting. When I first heard it watching TV, I wasn’t sure whether it was part of the soundtrack, e.g intentional fuzz, or a problem with the speaker. However, I was hearing it more than I thought I should, so checked with a frequency sweep, and it was very obvious as distortion when played through the left channel but not the right. The fact that I could stop the distortion by lightly touching the driver’s surround told me that the mid-bass driver was being driven outside its linear range. I snapped an FFT analysis to get some idea as to the magnitude of the distortion, as can be seen above.

halo

shs wrote: »

The answer to your last question is, yes and no. With music, it depends and only happened when there was fairly strong content in the mid-bass frequency range. Also, this type of harmonic distortion is often done on purpose, e.g. “fuzz” with electric guitars, and in the colloquial, sort of sounds like farting. When I first heard it watching TV, I wasn’t sure whether it was part of the soundtrack, e.g intentional fuzz, or a problem with the speaker. However, I was hearing it more than I thought I should, so checked with a frequency sweep, and it was very obvious as distortion when played through the left channel but not the right. The fact that I could stop the distortion by lightly touching the driver’s surround told me that the mid-bass driver was being driven outside its linear range. I snapped an FFT analysis to get some idea as to the magnitude of the distortion, as can be seen above.

Great job on recognizing and diagnosing the issue!

Now I have to be über diligent when listening for any issues.

Thank you for posting this information.

joecoulson

In my opinion, the mid bass driver (which I have already replaced one in my 705’s) are the weak links of these speakers. Otherwise very stellar.

halo

joecoulson wrote: »

In my opinion, the mid bass driver (which I have already replaced one in my 705’s) are the weak links of these speakers. Otherwise very stellar.

Hmmm. Design flaw?

joecoulson

Not sure. They seem to move more than the subwoofers when driven hard. Could be a design flaw in the power distribution between the drivers but I’m not sure.

halo

Ok. I don’t drive them that hard. Even when I played the soundtrack to Blade Runner 2049 the only drivers visibly moving were the Cassini woofers / subs

SCompRacer

halo wrote: »

I don’t drive them that hard.

Crank 'em up to 11.....

DaveHo

Crossover to the cassinis is too low IMHO. That said, they sound spectacular withn the limits.

joecoulson

DaveHo wrote: »

Crossover to the cassinis is too low IMHO. That said, they sound spectacular withn the limits.

I agree

halo

DaveHo wrote: »

Crossover to the cassinis is too low IMHO. That said, they sound spectacular withn the limits.

joecoulson wrote: »

I agree

Would’ve been nice to know this before I bought them

joecoulson

Not saying I don’t love them, I do. But even great products have their flaws. You will not regret buying them.

DaveHo

While they are not SPL monsters, you don't need to baby them. I have never bottomed out the mid-woof. That said, when running them full range, the 5 1/4 driver really moves. Play Pink Floyd, Mother & crank it up some. You'll see what I mean.

txcoastal1

Agree with Dave ^^^^ above

Right after the 705's were born and Russman still was a Polk rep we jammed these babies at LSAF for their debut...and you know how we do it at LSAF

From 12watts to 200+ watt amps these babies can play....do a search here on the forum

halo

DaveHo wrote: »

While they are not SPL monsters, you don't need to baby them. I have never bottomed out the mid-woof. That said, when running them full range, the 5 1/4 driver really moves. Play Pink Floyd, Mother & crank it up some. You'll see what I mean.

Performed this "test" with no major cone movement visible. This is probably because I live in an apartment & the "loudest" listening levels I get to here aren't very loud (perhaps by forum standards?). lol.

shs

The 705s certainly play loud enough for my purposes, and I live in a large house some distance from the neighbors with a dedicated home theater. Let's see if my signature block now has info. Tried several times, but no luck.

jayu969

Nice reviews...considering getting a pair of 705's myself.

mhardy6647

lightman1 wrote: »

Manticore wrote: »

lightman1 wrote: »

Manticore wrote: »

lightman1 wrote: »

I don't have a home....

Yeah but is any of your equipment located close by?

Where you at?

I was just funnin with you since you seem to have equipment in many,many states.
Southern NH, about an hour S SE of @mhardy6647

You're in luck.... There is a big amplifier of mine floating around near you. Call Doc.

It is true, but the amplifier in question is still in rehab.

We wanted it to go to rehab, and we said, yes, yes, yes.

verb

halo wrote: »

F1nut wrote: »

Victor, if you call Conrad-Johnson they will tell you that Steve McCormack is no longer there.........just saying ya know.

Yes, I caught that thread.

Thankfully, SMC is up and running in California!

That Conrad Johnson amp @verb has looks like a beast

Hey Vic just caught this. Yes it is! I've got it paired with the VTL pre and SRS's with new tweeters. Still breaking em in, but so far sounds fantastic! Was playing the new Bill Idol album rather loud last night and the CJ didn't break a sweat!

sponger

Just out of curiosity...why did you sell them?

halo

sponger wrote: »

Just out of curiosity...why did you sell them?

They were not a good fit for the rest of my setup. I preferred the sound of the Signature S60 speakers > that of the LSiM 705 speakers in my listening environment & on my gear.

I have since sold the Signature S60 speakers and I am now using Usher CP-6311 floorstanding speakers.

I hope that helps you. If you have any more questions, don't hesitate to ask.

sponger

That really is helpful. As a happy S15 owner, I can understand the appreciation for the Sig series.

vavan

shs wrote: »

The top graph is the "bad" left speaker and with a ~250 Hz signal, you can see the harmonics at 500 and 750 Hz are only 20-30 dB down and there is lots of hash at higher frequencies. With the "good" right speaker, bottom, you don't see any obvious harmonics. This was all done with my phone and used to show Polk the nature of the distortions.

What was the app used to get these graphs?

shs

Those graphs were made with SignalScope on my iPhone.

vavan

shs wrote: »

Those graphs were made with SignalScope on my iPhone.

I have neither iphone nor that app but wonder how would it look captured with say free rew app and standalone mic...

shs

That should be fine. I was not using REW at the time and love it now. Before I was using a sweep on a test CD and SignalScope as the RTA. In my case the distortion happened only during a fairly specific frequency range and I would have to pause SignalScope and save the image when I started to see the distortion. I would think that the RTA function of REW would work fine for capturing this sort of thing.

vavan

I only bought umik few days ago and really inexperienced in Rew at all so would have to figure out how to use rta

shs

I you have not already, there is lots of help in the REW page on the AVS Forum.