[James Romeyn]

Apology if this has been covered; I didn't search.

My prior room had the equivalent of several-thousand USD of ASC acoustic soffit on three walls.  Current room has little treatment, 1st side wall points damped, Room Tunes, etc.  I have done of lot of listening in a LEDE studio and have some recording studio experience.

We removed the huge sectional sofa (treated to maximize absorption/damping) to increase seating space for a live music performance in the soundroom.  After the party I noticed audio performance seemed better throughout.  I suddenly became intensely curious what would be the effect of replacing the 2/3rds of the carpet on the listening side with a highly reflective surface.  I am familiar with the reflective surfacing usually recommended on absorption controls to maintain reflectivity of higher frequencies while still absorbing lower frequencies. 

It hit me: I could hear the effect by laying down Visqueen or equivalent (*) over the carpet on the listening side.  It was nice of Debra to help with the A-B comparison and help lay down the plastic (only took a few minutes; music was a live recording of professional guitarist Austin Weyand playing guitars I sell at a performance I sponsored and attended).

The sound was far preferred (per both listeners) with the reflective floor vs. the carpet on the listening side.  Because the spkrs are so far out into the room, 2/3rds spacing put the plastic just .6' IFO the spkrs.  I later moved the plastic back several feet; most preferred was one foot further away from the spkrs.

My favorite builder says about $3/sf for nice laminate over the slab floor now covered by the carpet; need about 260sf.   

My 2 kopacts.

(*) Various parts of the floor were covered with either Visqueen, paper wrap used to pack cartons for home movers, or 3M brand "Hand Mask" for paint masking (on rolls).

There are safety and cosmetic reasons not to, but I'm considering covering an appropriate part of the floor at RMAF if I exhibit there as planned; the improvement was that huge...several of those, "Wow, never noticed that before" incidents occurred last night listening to familiar tunes.       

[Nyal Mellor]

What do you think is going on?

Do you think you're getting a frequency distorted reflection from the carpet (more absorption at high frequencies than low) and that by making it reflective it is not confusing the ear-brain processor?

I've been doing some (informal) experiments of my own on preference for front wall reflection (behind speakers) treated or untreated in dipole setups. Interestingly they have come out with a preference for front wall left reflective...

[James Romeyn]

What do you think is going on?

Do you think you're getting a frequency distorted reflection from the carpet (more absorption at high frequencies than low) and that by making it reflective it is not confusing the ear-brain  processor?

My guess is the improvement is from two items: The increased clarity exhibited by the increased ability to clearly detect individual strings on the guitar chords with no increase in fatigue (I listened many hours since the change) could easily be related to your first item above.  The increased level of later reflections is likely increasing the level of ambiance and the sound density per square inch, thus more closely mimicking live sound.  Also, and this may be as critical as anything else, large (commercial) spaces provide more reflectivity in the bass range than do domestic spaces; the increased later reflections may more closely mimic bass waves in a large space.     

I'm one of the very few people with a pure analog Trinaural system (three front channels; center is not summed mono...best described as a pure analog version of Meridian's Ambisonic DSP).  The  center speaker is of course centered; the L/R speakers are spread to the side walls (first reflection points well damped). 

Normal LEDE damps the 1/3rd of the room on the speaker side and the other 2/3rds of the room is live/reflective.  The centers of the L/R speakers are about 7-11" from the front wall.  25.8' room length x 1/3 = 8.6' or only .6' IFO the side speakers.  9.6' was preferred over 8.6; 10.6' sounded too dry and lost clarity so 9.6 it is.       

I've been doing some (informal) experiments of my own on preference for front wall reflection (behind speakers) treated or untreated in dipole setups. Interestingly they have come out with a preference for front wall left reflective...

IIRC dipolar fans may often prefer inverted normal LEDE, meaning the speaker end is live and the listening end dead. 

We have W2W carpet.  What type of floor do you have?  Hope to have my 2-piece bipolar monitors up and running shortly.  I left a request for my contractor to install laminate ASAP.   

[Duke]

At the risk of oversimplifying, if the off-axis/reverberant sound of a musical instrument sounds good, you don't want to lose that good energy to absorption.  Likewise if what your speakers are doing off-axis/in the reverberant field sounds good (which is not always the case), you don't want to lose that to absorption either. 

[Jeffrey Hedback]

Off-axis and what to do with it both in speaker design and room treatments...that is a large portion of Toole's research.

I think there are many combinations that can yield great audio.  One thing that most people don't put into the equation is the transient information that does NOT radiate politely from instruments or speakers.  Much of the richness, timbre and enjoyment of sound are in these transients.

As for the floor reflections, I'm a fan of wood floor in a listening room with area rugs selectively placed.  Again, there's not a "one size fits all" solution.  But true wood flooring (not so much laminate) offers a richness and warmth.  However, it brings the ceiling much more into play.  I think carpet has become a standard because it's the simplest way to yield an "appropriate RT60" for whatever that is worth.  However, there's almost always a more holoistic way to look at reflected energy across the frequency spectrum.

[jimdgoulding]

At the risk of oversimplifying, if the off-axis/reverberant sound of a musical instrument sounds good, you don't want to lose that good energy to absorption.  Likewise if what your speakers are doing off-axis/in the reverberant field sounds good (which is not always the case), you don't want to lose that to absorption either.

Heard that  .

[James Romeyn]

OK, now that some much smarter members have graciously added their wisdom, some questions:

The current Trinaural system (3ch, maybe best described as a pure analog version of Meridian's discontinued but more familiar Ambisonic DSP; center is not summed mono) employs three front monopole monitors actively HPX'd @ 80 Hz + an embarrassingly cheapo clone of Duke's SWARM four sealed sub system (AudioKinesis-licensed subs coming).  A bipole version of the above monitors is coming.

Is there a potential scenario in which the bipoles might sound better with carpet as is?  (the reflective floor surface is now gone)

My past LEDE experience was with the speakers against the front wall. Again, in my current rig the L/R speakers are 7-11" from the front wall, portraying tons more depth perspective than the prior LEDE system (probably not a surprise).  Conversely, the earlier LEDE system portrayed the size and space of the recording hall with more (startling) realism.  How might you quantify the potential of my system to increase its depiction of the recording space by covering the side walls between the L/R speaker faces and the listeners with cloth-covered OC703?  Leave OC703 face unadorned, add appropriate surface to maintain reflectivity of higher frequencies, or mix of both?  If the entire sidewall space described above = 100%, about 20% is now damped in the area close to the speakers; performance was preferred with reflective surfacing on the above described damping.         

Is ceiling diffusion more critical because of the lowish 7.6' ceiling height?  Is it correct that RPG Skyline diffusors (or equivalent) are best employed in the area between the speakers and listener only?  In other words, in my system, not behind the speakers? 

Consider this a solicitation for a DIY ceiling diffusor recipe, only if high certainty such equals the RPG.  Speaker is normal cone/dome in inverted vertical alignment, in case that affects reply.

...But true wood flooring (not so much laminate)  offers a richness and warmth...

Mr. Hedback
I read your bio and can only say welcome to our little hovel and I hope you never leave!

How likely might the laminate be worse than the tested mixture of Visqueen, thin plastic paint mask and paper wrap?   

     



     

[Jeffrey Hedback]

Hello James,

Thank you for the gracious welcome!  An inspiring hovel it is.

As for the laminate, tends to sound pingy compared to true hardwood (or even bamboo).  Interesting question as the visqueen/carpet system is not going to reflect as much hi/hi-mid energy as installed laminate (as the carpet underneath).  In your case, since you've identified areas that do help the cause (so to speak), it's likely the laminate would do nicely.  Of course in small areas, check out odd stock hardwood or even bamboo. 

To offer more valid insight on the larger questions goes to heart of the art and science.  Really takes a proper discovery.

With 7.5' ceiling, I'm not a fan of most diffusors.  If the ceiling is an issue, an absorption panel is likely the trick, 2" 703 minimum.


I like the "concept" of a full 703 canvas to ass strategically reflective/diffusive elements...a lot of options involved.  I have a preferred wood slat pattern that sounds very cohesive even at close distances....this comes to mind.

Do you have a floor plan diagram?

[James Romeyn]

Jeffrey
Wow!  I wasn't expecting this much whipped cream on my sundae!  A referral to free room layout software would be mighty welcome right about now.  Otherwise, will post room layout as soon as appropriate software is purchased, or may draw on grid paper, scan and post.

Many thanks!   
 

[Jeffrey Hedback]

Hi James,

There is a little bit of learning curve...but I really like Google's SketchUp.  Free version would do just fine.  However, graph paper's always good.