Does Speaker Stand Solidness Matter with Klipsch Cornwalls?

[T.H.E. Droid]

.....As someone suggested I would think think that the energy from the woofer is being used to create speaker sway rather than bass, so I likely might be losing something. Even if I'm not it still feels good to have sturdy solid stands..

We go back full circle to people giving advice who don't seem to have any understanding of physics. Speakers work in the first place by creating a force between the voice coil and magnet. Because the mass of the voice coil and cone is so small compared to the speaker frame/magnet and speaker structure, almost all the force is translated into cone movement. (The rest is lost in friction and heat.) To be able to cause the loudspeaker to rock (especially at woofer frequencies) wouild require a huge electronmagnet and thousands of watts of energy. Can an exploding firecracker taped to the side of an engine block cause it to move? Same principle and about the same differential.

Sure, having a stable structure is a good idea. Who wants to tip a Cornwall over on their foot or on a kid? But this concept of a 2 ounce voice coil and cone making a 60 pound speaker move is enough to make Sir Isaac roll over in his grave.

I'm not giving advise I was giving my thoughts on what I thought might be happening to get opinions. Ur just another guy who enjoys arguing. I think ur wrong anyway. How could the stability of the structure it's sitting on not make even a minute differences. Places sell hundred dollars stands to help with resonances and quality of bass and sound. Speaker cabs are built thick and strong for a reason so they don't resonate so much. So how could a wobbly stand not matter. I'm not saying its major but there could be potentially audible effect at some level. We reinforce cabs, why not stands. Many people including other high level audio guys would disagree. I know u guys like arguing so I hope u take the bait and indulge heavily. I honestly could care less, most of audio is a bunch of guys pretending to hear things they can't anyway. I'm probably guilty sometimes but atleast I can admit it. Lol if it makes u feel good build it. If u think it sounds better buy it.

It's really tough to help people understand the laws of physics when their "understanding" comes from watching movies where the laws of physics are absurdly violated every few seconds. My knowledge isn't based on watching science fiction movies, it's from doing NVH testing and analysis in the lab for many years. As I mentioned, there's certainly nothing wrong with having stable stands to put your speakers on, but the idea that a voice coil can move a 60 pound box at audio frequencies enough to make any audible difference in the sound is just plain ignorant. Sorry, but take some classes in physics and you'll learn to ignore some of these silly audiophile myths.

[Evolvo]

So if this little voice coil is like a fire cracker taped to an engine block then why does my walls and duct work rumble and shake. If u were right nothing should be moving. Apparently that fire cracker has more power than ur giving it credit for. So in theory the same vibrations that make my floors shake which weigh thousands of pounds could be make my minuscule stands vibrate which in turn can cause my speakers to vibrate, creating distortion and "sub harmonic transverse tonal imbalances", ok I might have made that last quote up from a movie, Lol

[Chris A]

So if this little voice coil is like a fire cracker taped to an engine block then why does my walls and duct work rumble and shake. If u were right nothing should be moving.

There is a difference between movement and boundary flex, which you reference here. It would be good to stiffen your walls next to your CWs in order to reduce flexure-related low frequency response loss below ~35-40 Hz. The use of a single sheet of "waferboard" screwed to the walls will reduce lf loss a great deal.

I'd listen to T.H.E. Droid - he's got it right on the "speaker movement" points that he makes. I know that this all seems counter-intuitive, but there are many studies and experiments that back up the discussions on "physics" and "acoustics" that you are receiving here...remember how much your CWs responded to being placed in the corners - even though you thought that it wouldn't make a difference?

Also note that line arrays are used a lot - I believe that you'd call them "flying arrays" used in commercial installs: These boxes/arrays are hanging by gravity alone...

Chris

[Mighty Favog]

Droid, there's no valid reason to be condesending on this forum. We are a friendly bunch with a wide variety of capabilities and experiences. We do raz each other from time to time but insulting the public as a whole is nothing but a self-serving attempt in increasing the size of your own ego.

If you want to help the OP that's fine. But there's no reason assume cenarios regarding his or anyone else's intellegence.

We're all here to have fun.

[artto]

I've said this before but I guess it bears repeating here.

In my room, which is partially below grade (42") with concrete foundation and floors, the wall corners are heavily reinfornced, First there is the standand 16" o.c. 2x4 studs. Between these are random vertical and horizontal 2x4 reinforcement. Each side wall has four 2x6 plates place in a diamond pattern. These plates are lag bolted to the concrete foundation wall. The wall itself of course has its top and sill plates secured to the top of foundation and concrete floor with concrete nails. The wall corners are covered 8 feet out from the corners with 1/2" solid core marine grade plywood and screwed (not nailed) to the wall framing. Then a layer of 5/8" sheetrock is screwed into the plywood underlayment and studs. A custom fit 2x10 corner plate was made and fitted air-tight to the corners and lag bolted to the foundation walls with 10 1/4" lag screws. The Klipschorns were then sealed air tight into the corners with closed cell foam weather stripping and the back corner plate of the Khorns were lag bolted with 8 1/4" lag screws to the 2x10 corner plate. The speakers are effectively mass loaded to the earth itself to carry any vibration away from the speakers and the room.

Extreme? Yes. Result? The walls still vibrate! However, the main resulting improvement in sound quality was not so much in the bass range as was expected, but rather in the middle and high frequencies. I can only theorize that the speaker, now being more physically stable in and of itself, has less movement in the xyz planes. While it may seem trivial, consider for a moment the very small distances that the speaker diaphragm in a horn loaded system is moving. Is it possible that the overall speaker system vibration is causing some smearing of the some from the higher frequency drivers as the move around in the XYZ planes due to vibration? I don't know. I don't have the equipment to measure it. All I can report is what I hear.

FWIW, Richard Burwen back in the 70's built a custom made room with built-in large horn loaded bass speakers of which the horn walls were made of multi-layered concrete block and encountered the same problem. The walls still vibrated.

[Mighty Favog]

Here's an interview of PWK I found that reinforces them being put up against the wall(s). Look at Page 2: Column 3: Paragraph 4.

http://www.aes.org/aeshc/docs/afternoon_klipsch.pdf

[Chris A]

Extreme? Yes. Result? The walls still vibrate! However, the main resulting improvement in sound quality was not so much in the bass range as was expected, but rather in the middle and high frequencies.

Have you considered the walls in close field to your midranges are not now flexing as much due to the bass bin output, and therefore aren't modulating midrange nearfield reflections as much?

Chris

[Turbox]

don't care that I lose bass because they are higher off the ground as I can't help that given I have 2 tier seating in my movie theater.

I think the better option in this case would be to use a slant riser, similar to what the Heresy uses. this way, you keep as much of the bass as possible and still feed your tier 2 seating.

I hadn't really given much thought to floor coupling until i had my KPT684 Sub. I think the standard use for this is to stand it up, and face it towards your seating. In fact the best performance i got out of mine was to lay it down on its side, radiators facing the wall. I adjusted the distance from the wall to find the sweet spot is bass sound. Using the Floor coupling and wall, dont overlook it...

[Turbox]

Looks like you got it all sorted out now. good stuff...

[T.H.E. Droid]

So if this little voice coil is like a fire cracker taped to an engine block then why does my walls and duct work rumble and shake. If u were right nothing should be moving. Apparently that fire cracker has more power than ur giving it credit for. So in theory the same vibrations that make my floors shake which weigh thousands of pounds could be make my minuscule stands vibrate which in turn can cause my speakers to vibrate, creating distortion and "sub harmonic transverse tonal imbalances", ok I might have made that last quote up from a movie, Lol

Now who is the one arguing for the sake of it? Unfortunately, like many folks who ask questions, it seems you had already decided what to do (and actually did it before asking) and were simply looking for someone to agree with you. Why bother?

[T.H.E. Droid]

Droid, there's no valid reason to be condesending on this forum. We are a friendly bunch with a wide variety of capabilities and experiences. We do raz each other from time to time but insulting the public as a whole is nothing but a self-serving attempt in increasing the size of your own ego.

If you want to help the OP that's fine. But there's no reason assume cenarios regarding his or anyone else's intellegence.

We're all here to have fun.

Well, if you look at my initial responses you'll see I was taking the time to share my knowledge with this person, who then came back with an accusation that I was being argumentative because I didn't tell him what he wanted to hear. After a rude response like that, I see nothing wrong with my reply. Perhaps you should take the original poster to task for dissing people who take the time to share their ideas?

[Mighty Favog]

Droid, there's no valid reason to be condesending on this forum. We are a friendly bunch with a wide variety of capabilities and experiences. We do raz each other from time to time but insulting the public as a whole is nothing but a self-serving attempt in increasing the size of your own ego.

If you want to help the OP that's fine. But there's no reason assume cenarios regarding his or anyone else's intellegence.

We're all here to have fun.

Well, if you look at my initial responses you'll see I was taking the time to share my knowledge with this person, who then came back with an accusation that I was being argumentative because I didn't tell him what he wanted to hear. After a rude response like that, I see nothing wrong with my reply. Perhaps you should take the original poster to task for dissing people who take the time to share their ideas?

If that's the case, what you might want to be careful of is including the entire public in your exasperations when you determine that this one person is wrong. In doing so, you're attempting to elevate yourself to a level above everyone else and not just the OP.

To quote you: "We go back full circle to people giving advice who don't seem to have any understanding of physics."

So what you did was insult every other person that replied to the OP in this thread that were giving their suggestion to fix the problem.

If you want to reinforce your statements with credentials may I remind you that members of my family (and after posing the voice coil/ magnet questions to them) are curently employed by GE Aircraft Engines at their manufacturing facility in Ohio. People that perform NVH (Noise, Vibration and Harshness) testing on evey engine that rolls off the assembly line, have concluded that your statement leaves too many variables unanswered to be conclusive.

But for now, I have better things to do.

[artto]

Extreme? Yes. Result? The walls still vibrate! However, the main resulting improvement in sound quality was not so much in the bass range as was expected, but rather in the middle and high frequencies.

Have you considered the walls in close field to your midranges are not now flexing as much due to the bass bin output, and therefore aren't modulating midrange nearfield reflections as much?

Chris

Chris, actually yes, but I don't think that's the case in this particular instance.

Just for a point of reference, the upper walls on three sides (L,front &R) are above grade and have the usual "stepped back" catwalk. The upper walls themselves are triple layered wih multiple layers of 1/2" Celotex, and 3/4" air spaces, each of which have silicone beading to seal the seams and provide some resilience/energy absorption between each layer. The 1/4" Masonite polycylindrcal diffusers are wedged in between the catwalk and the ceiling. These also have some resilience. Some have argued that they are re-radiating the sound back into the room like passive radiators. That may be but if they are the audible benefits out weigh any detrimental artifacts IMO. The polycylindrical surfaces begin at about the same height as the top of the bass horn. The polys are also angled and "droop" under their own weight providing a natural multiple radius transitional curve to the reflecting surface ~ truely "poly" cylindrical as opposed to just meaning many curved cylinders of a single radius.

I'm designing some bass range QRD for the upper wall front corners, a broadband one for the front center between the two large veritcal polys and the same for a couple on the rear walls. Actually the rear wall is offset with an angle in between. This was done primarily to get more depth in the room as opposed to acoustics (although there are benefits) and was limited by a staircase and the locations of utilities entering the house.

[svberger]

Decided to do my own little experimenting today

 

 

Had some spare Wharfedale W60's lying around. Haven't been able to sell them, didn't want to just give them away. Reading this thread and some others and thought "what do I have that I could use to go under the Cornies?" Voila! 

Jury is still out, but it's not bad.