The LS50's mid/woofer xmax is about 3mm, with an Sd of ~75 square cm, which isn't a whole lot of linear displacement to work with. Even with a port to augment output below 100Hz, there's obviously limits as to how much clean output you can expect. This is exacerbated by running the system full range, as there is nothing to protect the driver below tune, so it can very easily hit its mechanical limits with the right material.
Interesting, thanks. Would you happen to know how that compares to the CM5 S1 or S2?
This seems to support what I am hearing, I just figured since they're rated at 106 dB that I would be able to play something like the song I reference in my response to KEW down below at a little over 90 dB in a small room without issues.
I have never heard any such mechanical noise nor audible distortion but I have also never pushed them to anywhere near even 90 dB from my seat or say 95-96 dB at 1 meter.
I am now test driving them with my new 5 watt amp full range, sounds just as transparent so far.
That's actually the exact point where I start to hear that noise, in the low 90dB range @ about an 8' distance. Keep in mind that the room I have them in is very small, 13' x 10.5' x 7'. It's not like I'm trying to achieve that spl in a large space.
I have a KEF Kube 10b subwoofer with my LS50's and because I use them on my desktop, the Bluesound Powernode 2 streamer/amp's 60 watts per channel can drive them far louder than I ever want to listen at only 30" from them. I have the audio output settings of the Powernode 2 set to "no subwoofer" so the LS50's are getting full range signal. Never have had anything close to excursion limit problems. I love 'em.
Yes, as I was tinkering and setting them up in order to get the best possible imaging I quickly realized that nearfield is what these are really designed for and is what they excel at. I will discuss more about my impressions of the LS50s in a later post. I figured we'd get past this excursion issue first.
Why would you want to run these speakers full-range? If you listen loud, it is never a good idea to run a small ported (especially, sealed speakers aren't as prone to bass issues) speaker full range. KEF may have put some type of filter to reduce signals below the port tuning frequency.
Can you give some examples of what music and how loud and what you are using for the amp? That can help verify that you are putting high demands vs a defective speaker (which is very unlikely, but worth verifying) or amp clipping with bass(?).
In light of Steve81's well informed comments, the obvious is that you can add a sub crossed at 100-120 Hz and get the superb quality of these speakers while avoiding the problem areas you are having with bass.
I guess I was hoping that the LS50 would at least handle dynamic impacts as well as the other two ~$1.5k retail speakers I've had in here recently. For example the slightly larger CM5s can handle everything (within reason) that I can throw at them without flinching, I can also say the same for the LSiM 703s (but of course they are large cabinets). I guess it boils down to an application thing.
As far as I know the Yamaha A-S801 has a sub out that crosses at 90 Hz but I believe the speakers still run full range. The Hsu unit you linked is interesting, thanks.
Anyway, I kinda like using a stand-mount that I can run full-range. I was a heretic when it came to subs and stand-mounts for 2 channel music but I tried a REL sub and I became a believer. I connect it as they suggest, directly to the amps speaker terminals (same ones that the stand-mounts are connected to so the speakers and sub get the same full range signal) and the results are fantastic. I guess it could sound good also with a line level but you know how it is, it's human nature to stick with something that you've had excellent results with.
One of my test songs where I can hear this excursion limit is Chuck Mangione's
Children of Sanchez (Overture). This is an old school recording, we're not talking about a loudness compressed recording or even a recording with overcooked bass, these are just highly dynamic impactful drum hits. At the 3:38 mark the drums kick in and you can hear it there. The LS50s can't handle them at slightly above 90dB.
