Another reminder about room acoustics....

My living room is open on the right side to the dining area, on the left is a fireplace wall and bookshelves. I always had trouble due to the lack of sound reflection from the carpeted dining room, compared to the reflection off the fireplace and bookcase wall. Well...

We just finished some light remodeling, which included new carpet in the living (listening) room, and hardwood in the adjoining dining area. Got all my gear set back up last night and a couple of things were VERY apparent...

1) The bass in the room is much tighter now. I had a bit of a "bump" at around 50-60hz before, and it's noticeably flattened. I attribute this to carpet and padding that are much denser than the old carpet and pad. We installed a berber and a 120 ounce premium waffle type pad in the place of cheap contractor grade plush carpet and lightweight re-bond pad. Even the wife noticed that the rooom sounds, in her words, "clearer" and "richer"- and that was on a Steely Dan CD she's really not fond of.

2) The image is better defined and there is more ambient sound. I didn't have to try and skew the speakers to make up for the lack of a primary reflection from the right side as I did before. There's still obviously a difference between the left siding having a wall and the right a dining room, but with that dining room floor covered in a reflective surface, there is a lot more sound coming back than there was before, when it was basically a black hole for sound.

3) I hadn't really listened in a week or more since the house was torn up and things always sound better after an ear vacation it seems.

I think the biggest surprise was the improvement in bass which I attribute to the carpet and pad (correctly?). Next time you're looking at that stuff keep it in mind that better pad not only lasts longer and feels better, it might very well sound better.
Well, hate to burst the bubble but I don't think your carpet or pad had anything to do with the bass. It may have changed some other things--but not the bass. A 60 Hz wavelength is over 18 feet long. The quarter wavelength is nearly 5 feet long, which is how thick an absorber would need to be to attenuate it effectively. Anything below 1/8 of a wavelength and as a pure absorber it will not be effective. So, for the carpet and pad to make an appreciable difference at 60 Hz it would need to be between 2 1/2 feet and 5 feet thick.

I don't doubt that you perceive tighter bass, but I'll offer probably another reason for this. The bass hasn't changed appreciably--but other things have. The higher reflectivity and longer reverberation times from the dinning room have brought the mids and highs up. Now you have a better balance, and the bump that was bothersome before, is now not so noticeable. In fact, you may not have had a huge problem in the bass before, but just an over attenuated high frequency problem.

I'm glad it sounds better. It would have been interesting to measure frequency response and energy time curves before and after the changes. If anyone else is making changes like this--think about having measurements made. It could really help in improving your sound--and you'll know what direction to go and where the major diffeciencies lie.
Congratulations, Rives on your joint product of the year award in the Dec. 2003 issue of Sterophile.

As to your post above, Rives, could a 1.5 to 2inch combo of dense carpet and pad be the equivalent of a somewhat thicker peice of acoustic foam? As opposed to say a 3/4 inch thick high-traffic carpet with little or no pad?

Density does change the absorption coeficient, but does not change the bandwidth significantly. You can see this in the compendium of materials for noise control by comparing 6 lb per cubic foot fiberglass to 3 lb per cubic foot.

Damn science disproving my pie in the sky notions about the best tweak of the year being $0.51/SF carpet pad...

Whatever caused it, I am a happy camper.