Multiple different speakers same spot bass results

[Kvn_Walker]

I’m already in a carpet room. Would adding an additional area rug help out?

Perhaps depending on the carpet thickness. At least that's a cheap experiment (free if you keep your receipt ). My house is hardwood all throughout.

Come to think of it, when I moved the Canton's to the living room to set up for demo, their bass response was night and day better than in my office. The living room has a large area rug. I hadn't even considered this.

 

[TheWarrior]

I wouldn't be doing anything without taking measurements!

 

[highfigh]

The speakers determine the placement. They all don't radiate sound in all directions in the same way- look at a polar response (if you can find one for each) and they'll all be different. Don't try to put all speakers in the same place and expect to hear the same sound- it's not gonna happen.

Also, "floor bounce"................first reflections come from all surfaces. It's the direct sound and reflected sound interacting that causes phase cancellations and this is called 'interference'. It can be constructive, destructive or it may not do much of anything- watch the waves interact with someone else's wake behind a boat and you'll see a good example of this, although the vertical will not be as apparent unless the waves or wake are large. If you watch the surface of the water inside of a break wall, standing waves are easy to see, too- that's the reason break walls aren't parallel to shore or flat, rocky outcroppings.

 

[ematthews]

SO with all this said.. What is a good room size to have a 2.0 or 2.1 system in. All my ceilings are 8 feet. Just want to know the ideal room size to help this out. Maybe just maybe I can get an OK from my wife to switch up a room for my audio stuff.

 

[Swerd]

I also have a small listening room which limits my placement options, and experience this suck-out to some extent with my towers. What about using area rugs or carpet squares in front of the speakers to "catch" the floor bounce? I could get away with a large center rug over the hardwood floor if need be.

I’m already in a carpet room. Would adding an additional area rug help out?

Carpets and rugs have little to do with it. At 100 Hz, the wavelength is about 11 feet. Waves that long reflect equally well off of smooth hard surfaces or fuzzy soft surfaces. Rugs or carpets, wall or window coverings can reduce audible reflections at much shorter wavelengths (higher frequencies), but carpets, etc. are essentially invisible to bass sound.

The best way to deal with canceled bass due to floor bounce is to adjust the distance between the speaker & listener, or to raise the speaker if possible. That's why a subwoofer, in a different location than the speakers, can help. Locate the main speakers for the best mid range & treble sound, and locate the subwoofer for the best bass sound.

 

[ematthews]

As for room size. We have a great den area, but it's not a private listening spot for me. The acoustics for my HT are fantastic. The room is 15x24 approx. Would love to change my audio room here but then I am forced into only playing music when the wife isn't around. As well as dealing with Cats jumping all over the equipment.. Sucks to say the least.

 

[Kvn_Walker]

Carpets and rugs have little to do with it. At 100 Hz, the wavelength is about 11 feet. Waves that long reflect equally well off of smooth hard surfaces or fuzzy soft surfaces. Rugs or carpets, wall or window coverings can reduce audible reflections at much shorter wavelengths (higher frequencies),but carpets, etc. are essentially invisible to bass sound.

The best way to deal with canceled bass due to floor bounce is to adjust the distance between the speaker & listener, or to raise the speaker if possible. That's why a subwoofer, in a different location than the speakers, can help. Locate the main speakers for the best mid range & treble sound, and locate the subwoofer for the best bass sound.

Last night I made plinths out of solid acacia cutting boards and placed the F30's onto those to improve decoupling. Playing test tones and bass-heavy music, I could place my hand on the boards and feel the vibration but felt nothing on the floor underneath and immediately around the boards. And my sweet-spot bass was definitely stronger!

It's equal parts frustrating and fun to meddle with the physics of something you cannot see.

 

[ematthews]

I have full carpet in my room. Even with spikes on the bottom of my speakers, I feel the vibration through the floor. I am not sure how I could decouple the floor even more with out the Speakers becoming unbalanced. I would need a very heavy piece of granite or something else. Then put the speaker on top of it. My floor standers are heavy and tall, so they become top heavy very quick.

 

[KEW]

I have full carpet in my room. Even with spikes on the bottom of my speakers, I feel the vibration through the floor. I am not sure how I could decouple the floor even more with out the Speakers becoming unbalanced. I would need a very heavy piece of granite or something else. Then put the speaker on top of it. My floor standers are heavy and tall, so they become top heavy very quick.

If you want to decouple from the floor you need to get rid of the spikes!
Try a couple of 2-foot by 2-foot pieces of three quarter inch plywood or anything of the like to give a stable surface as a test.

 

[ematthews]

If you want to decouple from the floor you need to get rid of the spikes!
Try a couple of 2-foot by 2-foot pieces of three quarter inch plywood or anything of the like to give a stable surface as a test.

And on top of these, just use the standard feet over the spikes. Correct?I have some very heavy 18x18 ceramic tiles that I may be able to stack up.

 

[Kvn_Walker]

And on top of these, just use the standard feet over the spikes. Correct?I have some very heavy 18x18 ceramic tiles that I may be able to stack up.

If you don't want that huge 18x18 imprint in your carpet, you could also use isolation pads at the corners underneath the concrete. (I call them "corkboard cookies").

Now I do get floor vibration, but it's a ways forward of the lateral plane of the speakers. That's just where the soundwaves hit the floor. That can't be prevented. But if you've decoupled them well enough, the floor won't absorb cabinet vibration and you shouldn't feel anything on the floor in the immediate area around the base of the speaker.

 

[ematthews]

If you don't want that huge 18x18 imprint in your carpet, you could also use isolation pads at the corners underneath the concrete. (I call them "corkboard cookies").

Now I do get floor vibration, but it's a ways forward of the lateral plane of the speakers. That's just where the soundwaves hit the floor. That can't be prevented. But if you've decoupled them well enough, the floor won't absorb cabinet vibration and you shouldn't feel anything on the floor in the immediate area around the base of the speaker.

I should have added that I am on an upstairs floor that is carpet on wood. So I know this is not the best type of flooring and from what I read, it's hard to decouple anything on this type.

 

[KEW]

And on top of these, just use the standard feet over the spikes. Correct?I have some very heavy 18x18 ceramic tiles that I may be able to stack up.

The carpet can act as a pretty decent "de-coupler", but the spikes penetrate through the carpet and give a solid connection to the subfloor.
AFAIK, the only good of spikes is to give a solid footing for your speakers if you have thick "spongy" carpet that allows a speaker to get knocked over easily (IOW, on a hard floor, if you tilt the speaker by pushing the top 2" sideways, you will feel a fair amount of force trying to right the speaker. On a thick, cushy carpet (w/o spikes),you can push the top over the same 2" and feel very little resistance (think 2" thick memory foam for an even more dramatic example of the mechanics).
Laying down a larger sheet of plywood (or anything that is hard) will spread the weight over enough area that the carpet won't give much under the sheet and the sheet stays flat ... essentially mimic-ing a hard floor. If you end up going this route (and especially if the stance of your speakers is not too broad),it is better yet to fix (screw/glue) the sheet to the bottom of the speaker, making a plinth. That way when you start tipping it, it is the outside edge of the sheet that forms the pivot point and the resisting force is greater.

To answer your question. Use the rubber feet or whatever the standard non-spike feet are supplied. The reason is the tips of the spikes are fixed pretty rigidly (because the bottom corners of your speakers are rigid) and the tile is rigid. Three spikes will contact the tile perfectly (tripods don't wobble!) but the forth is very likely to be a little above the tile - you could end up with a vibration at this contact point! The rubber feet will allow enough give to let the forth support point make solid contact. If your feet are not rubber but something rigid, I would cut a piece of thin felt or carpet grip to assure contact at all four points (or at least make certain there is already contact at all four).
The spikes (if they are sharp) work fine with wood, because the first three will penetrate deeper into the wood than the fourth to allow all four points contact.

Edit: I should add that I am not convinced there is any significant benefit to having the speaker coupled to or de-coupled from the floor with typical construction!

 

[Swerd]

This thread has drifted away from the topic of floor bounce to the question of floor spikes and floor decoupling (or is it coupling?). I don't think the posters involved are confusing floor bounce with floor decoupling, but other readers might.

So to be clear, floor bounce is an acoustic phenomenon. It takes place after speaker cones create sound waves that move through the air.

Floor spikes prevent motion and vibration between speaker cabinets or stands and the floor. The spikes couple the cabinet or stand to the floor, especially a carpeted floor. This has nothing to do with losing bass due to floor bounce.

 

[Kvn_Walker]

This thread has drifted away from the topic of floor bounce to the question of floor spikes and floor decoupling (or is it coupling?). I don't think the posters involved are confusing floor bounce with floor decoupling, but other readers might.

So to be clear, floor bounce is an acoustic phenomena. It takes place after speaker cones create sound waves that move through the air.

Floor spikes prevent motion and vibration between speaker cabinets or stands and the floor. The spikes couple the cabinet or stand to the floor, especially a carpeted floor. This has nothing to do with losing bass due to floor bounce.

Yeah sorry about the derail. But we were at least still discussing speakers and not rifles.

 

[Swerd]

Yeah sorry about the derail. But we were at least still discussing speakers and not rifles.

That wasn't a real thread derail. Everyone knows when that happens:

What we had was more like thread drifting – more confusing.

 

[KEW]

That wasn't a real thread derail. Everyone knows when that happens:

What we had was more like thread drifting – more confusing.

I see you are using the extra time from retirement wisely!!!

 

[Swerd]

I was having too much fun searching for thread derail memes & gifs. Here are some others I liked but didn't use.

And finally, abandon thread

 

[Swerd]

I couldn't get the first train wreck to post. See it here:
https://cdn0.vox-cdn.com/thumbor/Vej_z-sg_uodoV7ggLIpCXHyFbs=/800x0/filters:no_upscale()/cdn0.vox-cdn.com/uploads/chorus_asset/file/2533142/train-derail-o.0.gif

 

[KEW]

I couldn't get the first train wreck to post. See it here:
https://cdn0.vox-cdn.com/thumbor/Vej_z-sg_uodoV7ggLIpCXHyFbs=/800x0/filters:no_upscale()/cdn0.vox-cdn.com/uploads/chorus_asset/file/2533142/train-derail-o.0.gif

I love the guy who gets run over by the train!
Budget stop-motion at its finest!