Concrete flooring VS wooden flooring with JBL and Altec

[JBL 4645]

I’ve recently moved into a new home and since my passion is JBL, the sound of dramatically changed from common wooden floors that I have been so used to over the years.

Bass is more tighter with less, irritation of vibrations like buzzing and rattling that is often found with loudspeakers, playing different low note tones, at different sound pressure levels, where a loosen floorboard will only, induce a louder tone along with the sound that you’re listening to, whether its straight forward music or film soundtrack, where realism in reproduction is critical.

I know there’s a few members here that I have found to have concrete flooring, richluvsound has those huge JBL 4345 standing on a firm foundation that exhibited a nice solid bass line when I visited his home last July 26th 2007, they were void of any distractions like rattling and buzzing, just the pure sound was heard and felt.

The same thing I noticed with my small JBL control 5 and that huge monstrosity JBL 4645.

So please talk freely about you’re experiences with concrete or wooden.

[johnaec]

Concrete with carpeting! There's nothing worse than hearing high frequencies bouncing off a concrete floor.

John

[JBL 4645]

Concrete with carpeting! There's nothing worse than hearing high frequencies bouncing off a concrete floor.

John

johnaec

I’m rather surprised that JBL doesn’t recommend hard surfaces such as concrete, for good bass transmission, of all there loudspeakers. Yes the room has a very high reflectivity, that shouldn’t be no more than a few months, so I’ll have to grim and bare it until such time a carpet is laid down on the new surface.

[scorpio]

In my pre-JBL days, I had the same pair of speakers in a typical Belgian (read concrete floor) house, with nice, good imaging and solid bass (for the speaker), then moved to the US for a while in a typical US room (floorboard over joist, over a big open basement) with carpet, the sound was dull and lifeless, no proper bass, I had to move to panel speakers + subwoofer to get some life back. And this was not that the room was overdamped, it had to be something else.

This new gear got stolen when I moved back to Belgium, so I could only use the old speakers again over concrete, and they sounded just as I remembered.

Followed a short episode of larger panels (too big for the roomà, now I have JBL over concrete floor, I can make the cups and glasses rattle in the living room below, no problem of vibration in my listening area!

[Ian Mackenzie]

It depends on how solid a wooden floor you are talking about..there are no absolutes.

The concrete foor (I have one) will become quite elastic to particular low frequencies....nothing you can do about it. It also depends a lot on the rest of your room and the coverings.

[majick47]

The listening room for my L300 has a carpeted concrete floor and as far as I can tell the sound is very solid/focused. Some day I'm going to try some heavy duty spikes on the base of the L300. Right now I have black maple "dollies" with wheels under the L300 which was intended to raise them up about 4" from the floor. In my second system I have 4301b that are mounted on the wall with JBL heavy duty steel adjustable brackets. My brother fabricated a set of speaker stands from heavy steel for another pair of 4301b used in my surround system, another four 4301b are mounted/bolted to the side/back walls useing heavy duty adjustable steel brackets. The 4301b are bolted to the adjustable stands and again the sound is solid/focused on the carpeted concrete floor. Sometime in the future if I decide to remodel the room and remove the wall to wall carpeting I might consider putting down hard wood flooring over the concrete with large area carpets. The wall to wall carpeting at this time makes for a less than lively sound from the L300 and the combination of concrete floor with solid wood flooring and area carpets might make for a better balanced sound IMO.

[JBL 4645]

It depends on how solid a wooden floor you are talking about..there are no absolutes.

The concrete foor (I have one) will become quite elastic to particular low frequencies....nothing you can do about it. It also depends a lot on the rest of your room and the coverings.

Ian

Same thing can be said about an Earthquake, first the (P wave) Primary wave followed by the (S wave) seismic wave, no wonder the earth moves violently. No wonder concrete is loosened!

This was kinder like what I expected to hear. I would appear that a solid floor makes a huge difference, rather than a few odd flimsy loosen floorboards that makes the sound weak.

[Ian Mackenzie]

Yeah it will block some of the LF front reaching the floor below.

But with a constant amount of energy going into the room and no where for it to escape you get a build up and modes and they start to ring like a bell but it more of a boom.....the whole joint hums to the point where there is a loss of definition.

I would suggest a thick rug and get some wood in there and a sofa at least.

Ian

[Andyoz]

The concrete foor (I have one) will become quite elastic to particular low frequencies....nothing you can do about it.

Ian, is that a "suspended" concrete slab. They can be set into resonance in the 100Hz to 200Hz range depending on thickness, etc.

It's the co-incidence dip resonant condition. Sounds like a "drone" sound when you hear it tested.

[JBL 4645]

Yeah it will block some of the LF front reaching the floor below.

But with a constant amount of energy going into the room and no where for it to escape you get a build up and modes and they start to ring like a bell but it more of a boom.....the whole joint hums to the point where there is a loss of definition.

I would suggest a thick rug and get some wood in there and a sofa at least.

Ian

Ian

There is a sofa in the JBL room, I guess a rug is no, becuase it only covers a small area. Carpet yes, but that's going to take a while.

There is this article that I read many years ago about the screening room at Dolby labs San Francisco in the (What Video December 1991) I still have the magazine for reference reading. In it they describe how the cinema was built in brief.


“The entire cinema and projection room are built as a (floating box) to ensure that no sound filters in, even though there is a busy motorway less than 100 yards away, and to make equally sure that no sound filters out, even when films are screened at deafening levels”.

“The sound insulation includes 42 tones of rock. The electrical wiring relies on four-and-half miles of cabling. The power amplifiers for the screen and surround-sound speakers are rated at 16 kilowatts output”.

The screening room at Dolby Laboratories
in Wootton Bassett, UK.

"The ‘screening room’ itself would easily put the best of the UK’s cinemas to shame – not only is the equipment installed by the experts who design the technology but the room is actually suspended within a concrete shell. This means it has one of the world’s lowest ambient noise ratings for a cinema, despite being directly underneath an impressive water feature in the car-park and the flight path of planes heading for RAF Lyneham".

[hjames]

Yes, but proper sound studio design with floating rooms, isolated windows and doors, baffled air-space in the walls, and angled windows is probably a LOT more of an investment than you'd want to make in that home.

Like other folks have said - a layer of carpet on the floor and perhaps some room conditioning is much easier to approach.

And as Bo would ask - have you measured the response of your room as it stands now? Without a baseline reference its hard to know what you have to deal with, or what to worry about

Ian

There is a sofa in the JBL room, I guess a rug is no, because it only covers a small area. Carpet yes, but that's going to take a while.