Harsh sounding room

[nzlowie]

Hi guys

 

Still having some trouble getting my sounds right since setting up my new room. The room sounds harsh, ok at lower volumes but as soon as you crank it up it starts sounding hard. I’ve tried various equipment changes to tame it down but these always come at the cost of something else.

 

The room has foam panels on the front wall, absorbers at the first reflection points and the rear wall has a heavy acoustic curtain over the windows, carpet floor. The wall construction is plaster board. When I ran REW sweeps I could see that bass still needs a bit of taming but above 200-300 it decayed evenly and smoothly yet when I did the “clap” test I could hear ringing.

 

What now? More absorbers or diffusers on the rest of the walls or start work on the ceiling?

 

Appreciate your thoughts.

[VanArn]

 If you can access some other quality  floorstanding speakers, try them in the same position. It may not be the room at fault but an issue with the combined sound from the horns not integrating at your preferred listening position.

[nzlowie]

No, haven’t got access to anything that would even come close to the level of these horns. I know they sounded absolutely beautiful in my last room which was slightly larger but that was brick and plaster walled so I thought that would have been more reflective.

 

Setting and speaker placement dimensions are just about identical to my last room.

The old room also didn’t have the clap echo that I have now.

 

Don’t get me wrong, this isn’t a bad room just that I’m trying to make it better.

[Snoopy8]

40 minutes ago, nzlowie said:

Setting and speaker placement dimensions are just about identical to my last room.

The old room also didn’t have the clap echo that I have now.

Not sure "just about identical" is an accurate description because you have clap echo now and not previously.

 

Soft material in the room will help. Your floor needs some rugs, the heavier the better. Add cushions, throw rugs, more furnishings.  There is trade-off between what you prefer in looks versus sound quality. Experiment with various amounts of furnishings.

[BATMAQN]

Are the walls insulated and does the carpet have thick underlay it does help?

 

Here is my pathetic attempt at acoustic tiles at the time of doing this I read that corners play havoc with frequencies so I did put some corner sections in apart from the ceiling cornice I didn't bother with that mainly because it was a pain to do, I do think the ceiling tiles above the speakers which are just eBay ones do actually help and don't underestimate how much extra bits of furniture in the room apart from hard surfaces help to diffuse certain frequencies.

 

Do you think moving the speakers out from the back wall maybe a metre would help and move the listening chair back in fact I'd swap the big sofa for the little one that would probably do more diffusing front on and that coffee table thing on the right get rid of that or at least move it further back, way back.

 

The tiles are mirrored on the back section of the room as well where I sit as cheap and nasty as this looks it does actually work for me my room isn't harsh.

 

Have included an insulation picture I don't know if it helps but it seems to.

 

 

[nzlowie]

Good work, thanks for the pointers.

Yes the walls and ceiling is full insulated, the carpet has 12mm underlay.

Will try moving things around and see (hear) what happens. I tried to keep the listening chair 38% from the rear wall as the experts tell us, if I move the speakers any further out I'd have to moving the chair back and end up with it close to the back wall. 

I could move the couch to where my central chair is and then put the singles on the side walls.

 

There are a couple of extra absorbers laying around somewhere which I might need to put up. Her in doors wants some art/photos on the walls as well  but the two don't really work together. The walls not that big!

Maybe get some more pads for the ceiling?

[nzlowie]

Also for HF absorbtion can I get away with 50mm insulation pads? I know the 100mm work better at lower frequencies.

[BATMAQN]

26 minutes ago, nzlowie said:

Good work, thanks for the pointers.

Yes the walls and ceiling is full insulated, the carpet has 12mm underlay.

Will try moving things around and see (hear) what happens. I tried to keep the listening chair 38% from the rear wall as the experts tell us, if I move the speakers any further out I'd have to moving the chair back and end up with it close to the back wall. 

I could move the couch to where my central chair is and then put the singles on the side walls.

 

There are a couple of extra absorbers laying around somewhere which I might need to put up. Her in doors wants some art/photos on the walls as well  but the two don't really work together. The walls not that big!

Maybe get some more pads for the ceiling?

Every situation is different comes down to your ears in the end these so called experts can't get it right every time its not a blanket solution for all playing around with the furniture costs nothing and can yield results.

 

24 minutes ago, nzlowie said:

Also for HF absorbtion can I get away with 50mm insulation pads? I know the 100mm work better at lower frequencies.

I've used 50mm for the HF I don't have any complaints but I'm no expert. 

I think it's a combination of everything in the room contributes something even those fake plants I've got may be doing some diffusing anythings possible and they look nice.

Edited March 2, 2020 by BATMAQN

[Snoopy8]

It is not difficult to overcome clap echo if you understand the absorption coefficient of surfaces

https://www.acoustic-supplies.com/absorption-coefficient-chart/

 

Echo is caused by repeated reflection of sound from all the hard surfaces. Having walls and ceilings insulated underneath does not change the reflection properties of the walls and ceilings.  Adding absorption panels will definitely help.

 

Easiest and cheapest is to add soft furnishings. It is easy to experiment as well.

[nzlowie]

Put some extra absorbtion panels around plus some the wife's quilts and it's better. Still a bit of clap echo, wondering if I need to do something with the ceiling?

Fair amount of the walls treated now so what next?

Maybe diffusion?

[Satanica]

42 minutes ago, nzlowie said:

Fair amount of the walls treated now so what next?

Perhaps you could try covering all of the leather lounges with sheets or blankets.

[nzlowie]

Not actually leather.... Leather look fabric!

[Guest Peter the Greek]

I'd hazard a guess you have ineffective absorbers (foam is notoriously ****). It would seem to me you've got sufficient absorption in somewhat appropriate places.

 

That or its positioning.

 

Or a speaker issue (not likely)

 

Where do you live? I'd get someone like Paul Spencer around to advisr before you go spending more money on "stuff" that may or may not help.

[Snoopy8]

3 hours ago, nzlowie said:

Put some extra absorbtion panels around plus some the wife's quilts and it's better. Still a bit of clap echo, wondering if I need to do something with the ceiling?

Fair amount of the walls treated now so what next?

Maybe diffusion?

As I mentioned to OP, experiment by adding more soft material into room to absorb sound. It is total amount of absorption, not number of panels, nor their positioning on walls. 

 

It can be done cheaply with your furnishings. Try temporarily hanging a rug on a blank wall. Adding a bookshelf with books is another way.  

[Guest DrSK]

On 03/03/2020 at 7:09 AM, nzlowie said:

Setting and speaker placement dimensions are just about identical to my last room.

The old room also didn’t have the clap echo that I have now.

None of your absorbers are full range, most people's aren't.  This means there are still reflections even from first points.

 

My room went from harsh to much better with small changes in speaker and listener position.  Tuned room coupling with the speaker positions and also the reflected time delays. Time delays were too high at first off the sidewall reflections and were making it harsh, an increase in speaker spacing reduced the time delay. I then had to increase toe marginally as the width increase got me a bit far off axis.

 

I've got imaging well beyond speaker width and good height above the speakers from just at the speaker front to well behind the wall somewhere. On some of Roger Waters 3-d mixed stuff I'm getting full 180 to 200 degrees of wrapped sound from 2 channel. Speakers have good smooth off axis response where side wall reflections are not necessarily bad.

 

I'm not currently running any absorption at first reflections and finding research on inter aural cross correlation, precedence effects and the benefits of reflections to basically eliminate comb filtering some interesting reading. 

Edited March 8, 2020 by DrSK

[nzlowie]

I don’t have an issue with imaging or sound stage, I know some of that Roger Waters stuff goes right around and envelopes you. Just want to smooth it out.

 

As it’s pretty clear my room needs a fair bit of work I contacted on of consultants who publishes some good info on youtube and his site. Sure he could work out what was needed and supply…… cost $25k!!!! That’s not going to happen!

Also sent an email to Paul at Red Spade to get his advice.

[nzlowie]

You also mention that the absorbers aren’t full range, so what do we use? Some say that foam is c**p and I also got told by an expert to stay away from building products eg rockwool. So what do we use for our absorbers then?

[Guest DrSK]

1 hour ago, nzlowie said:

I don’t have an issue with imaging or sound stage, I know some of that Roger Waters stuff goes right around and envelopes you. Just want to smooth it out.

I stil had OK imaging, but still harshness due to time delays bring a bit long. 

1 hour ago, nzlowie said:

 

needed and supply…… cost $25k!!!! That’s not going to happen!

 

Hard for consultants to make money off home acoustics.  Materials were always about $1000 a metre installed and time is $2000 a day otherwise why bother with the home market, just keep with commercial clients. 

[Gee Emm]

Based on your photos, your ceiling looks to be your biggest culprit.

[AudioGeek]

9 hours ago, DrSK said:

None of your absorbers are full range, most people's aren't.  This means there are still reflections even from first points.

 

My room went from harsh to much better with small changes in speaker and listener position.  Tuned room coupling with the speaker positions and also the reflected time delays. Time delays were too high at first off the sidewall reflections and were making it harsh, an increase in speaker spacing reduced the time delay. I then had to increase toe marginally as the width increase got me a bit far off axis.

 

I've got imaging well beyond speaker width and good height above the speakers from just at the speaker front to well behind the wall somewhere. On some of Roger Waters 3-d mixed stuff I'm getting full 180 to 200 degrees of wrapped sound from 2 channel. Speakers have good smooth off axis response where side wall reflections are not necessarily bad.

 

I'm not currently running any absorption at first reflections and finding research on inter aural cross correlation, precedence effects and the benefits of reflections to basically eliminate comb filtering some interesting reading. 

How did you work out reflected time delay being the culprit?

[nzlowie]

16 minutes ago, Gee Emm said:

Based on your photos, your ceiling looks to be your biggest culprit.

Thats what I'm starting to think. Going to try fixing a duvet over the rear section tonight and see if that does anything, if so I'll put more effort into it.

[frednork]

is the slap echo louder at the front of the room or the back

[Guest DrSK]

58 minutes ago, AudioGeek said:

How did you work out reflected time delay being the culprit?

Full range absorbers are holy grail stuff and don't really exist in practical dimensions for home use. This means there are reflections from first points even with absorption.

 

I used $12k of 3-d architectural acoustic modelling software to show the issue. I use it on commercial projects. You need to know the time delay and and relative level. Then compare with precendence effect charts. I then tweaked my positioning and furniture which does have some absorption and could hear the differences predicted.

 

Anything approaching the second image zone is going to cause issues. And the flutter/buzz/ringing can also be a warning depending on its orientation relative to listening and speaker positions. There are trade offs between image spread against comb filtering and presence, fullness of room, ambience etc.  

 

If you find the difference in distance in metres between the direct and reflected you get time delay from the following. 

 

DifferenceDistance/343=time delay

 

You then need to know the relative level difference. Keeping it simple this is at worst:

 

20*log(reflected distance / direct distance), this must be in base 10.

 

Unless you particularly want to reproduce a studio where the room has no influence the use of good reflections can be beneficial musically and also solve comb filtering problems.

 

Still learning. I'm working through Sound Reproduction by Toole and Floyd at the moment. One of the few books aimed at 'small' spaces like your room and mine.

 

First point reflections are not always bad and based on blind listening tests can be good. Some high end speakers are designed for room reflections and have good off axis response to keep the overall room spectrum more even instead of only the direct signal. Our brain also locates off objects off the direct signal from the speakers, and so long as the room temporal field from reflections and reverb only add to the presence and don't disturb source location then some reflection can be of benefit. Since we are in 'small' rooms it is the first and low order reflections that create presence. Rooms are too small for proper reverb and most people end up with even lower reverb due to furnishings and unbalance absorption from carpets etc plus lots of thin panels. 

 

 

Edited March 8, 2020 by DrSK

[nzlowie]

37 minutes ago, frednork said:

is the slap echo louder at the front of the room or the back

Louder at the back but to me its almost like the angled roof has something to do with it as directly below the angle change its worst. No real change to the slap echo if I open the doors or not so I don't think its coming off the glass, they are covered by heavy acoustic curtains.

 

@DrSK all that stuff is way over my head! I can build anything but working out what to build is another story.....

[Guest DrSK]

16 minutes ago, nzlowie said:

 

 

@DrSK all that stuff is way over my head! I can build anything but working out what to build is another story.....

The roof would appear to be a likely issue. But hard to know for sure. I would recommend a bit of trial and error in chair positions and speaker positions. 

 

Can understand, I studied post graduate in acoustics at University of Canterbury in Christchurch (from Levin originally) and this stuff is harder and really not fully understood by anyone. My aim is to keep tweaking, reading theory, modelling and building stuff to see if there is a viable business compared with comparatively easy work like road design and environmental planning approval work that I'm normally doing acoustics for in NSW. 

Edited March 8, 2020 by DrSK