ASC tube traps: effect of their absence

[Al M.]

My room got the full treatment with devices from ASC (Acoustic Sciences Corp.). On these two system pages there are a few pictures of the room with tube traps, sound panels and window plugs:

http://www.whatsbestforum.com/showthread.php?17334-My-minimonitor-subwoofer-system/page2

http://www.whatsbestforum.com/showthread.php?17334-My-minimonitor-subwoofer-system

Also the carpet behind the speakers helps (the profound effect of the window plugs is described on my system page 2).

Before I had any room treatment, and also no carpet behind the speakers, my soundstage had been very flat. Introducing tube traps and sound panels allowed for spatial depth for the first time. Yet at some point I had done some brief experimentation, and after all the other room treatment subsequently added there was now also spatial depth without the corner tube traps.

Recently I lent the stacks of four corner tube traps to a friend, and thought, well, there might be some effect of their absence, but the harm done should not be too great.

Oh my, was I mistaken!

Even with all the other treatment still in place, including the thinner center tube traps, the sound changes dramatically by just removing the corner tube traps.

People who have listened to my system have repeatedly praised presence and 3-D palpability of sound images, as if you could 'see' the performers standing in the hall, or as if you could reach out and touch them, as it were.

Yet now all the palpability of imaging is gone. Really gone. Images are larger, more diffuse and with no palpability at all. Greatly diminished presence. The sound is also somewhat more echo-y, and spatial information from the recording venue proper seems to come through less.

What some people had found particularly special about my system is gone. It still sounds great, but....

Just astonishing.

***

Those were my first impressions, on small-scale classical material.

But then I went to jazz and rock, where there is more bass, and rhythm.

Unbelievable. Also my excellent rhythm & timing is gone.

The tube traps affect the mid-bass big time. Now my mid-bass is diffuse and bloated. At first it seems that there's more mid-bass without the tube traps, but that initial impression quickly fades away. it's just more bloated and far less precise. The fast bass transients that Madfloyd admired so much with Green Day on my system are gone. And my rhythm is gone. Not just Green Day. I tried some jazz, AC/DC, Zappa, Elvis, you name it. Gone.

Just remarkable.

It is obvious that in many rooms, like in mine, chasing for great bass without acoustic room treatment is futile. You could spend $ 20 K on upgrading your amps to get a better grip on your speakers, or on upgrading the speakers themselves -- if your room is the main culprit of blurring the bass, it won't matter. Four corner tube traps for just $ 2.5 K total will do the trick instead. You could try digital room correction, but also that only will get you so far. Nothing beats actual physical elimination of detrimental room reflections. Digital room correction on top of that is fine, but it cannot be a substitute.

Fortunately I'll get my corner tube traps back in a few days.

 

[MadFloyd]

My room got the full treatment with devices from ASC (Acoustic Sciences Corp.). On these two system pages there are a few pictures of the room with tube traps, sound panels and window plugs:

http://www.whatsbestforum.com/showthread.php?17334-My-minimonitor-subwoofer-system/page2

http://www.whatsbestforum.com/showthread.php?17334-My-minimonitor-subwoofer-system

Also the carpet behind the speakers helps (the profound effect of the window plugs is described on my system page 2).

Before I had any room treatment, and also no carpet behind the speakers, my soundstage had been very flat. Introducing tube traps and sound panels allowed for spatial depth for the first time. Yet at some point I had done some brief experimentation, and after all the other room treatment subsequently added there was now also spatial depth without the corner tube traps.

Recently I lent the stacks of four corner tube traps to a friend, and thought, well, there might be some effect of their absence, but the harm done should not be too great.

Oh my, was I mistaken!

Even with all the other treatment still in place, including the thinner center tube traps, the sound changes dramatically by just removing the corner tube traps.

People who have listened to my system have repeatedly praised presence and 3-D palpability of sound images, as if you could 'see' the performers standing in the hall, or as if you could reach out and touch them, as it were.

Yet now all the palpability of imaging is gone. Really gone. Images are larger, more diffuse and with no palpability at all. Greatly diminished presence. The sound is also somewhat more echo-y, and spatial information from the recording venue proper seems to come through less.

What some people had found particularly special about my system is gone. It still sounds great, but....

Just astonishing.

***

Those were my first impressions, on small-scale classical material.

But then I went to jazz and rock, where there is more bass, and rhythm.

Unbelievable. Also my excellent rhythm & timing is gone.

The tube traps affect the mid-bass big time. Now my mid-bass is diffuse and bloated. At first it seems that there's more mid-bass without the tube traps, but that initial impression quickly fades away. it's just more bloated and far less precise. The fast bass transients that Madfloyd admired so much with Green Day on my system are gone. And my rhythm is gone. Not just Green Day. I tried some jazz, AC/DC, Zappa, Elvis, you name it. Gone.

Just remarkable.

It is obvious that in many rooms, like in mine, chasing for great bass without acoustic room treatment is futile. You could spend $ 20 K on upgrading your amps to get a better grip on your speakers, or on upgrading the speakers themselves -- if your room is the main culprit of blurring the bass, it won't matter. Four corner tube traps for just $ 2.5 K total will do the trick instead. You could try digital room correction, but also that only will get you so far. Nothing beats actual physical elimination of detrimental room reflections. Digital room correction on top of that is fine, but it cannot be a substitute.

Fortunately I'll get my corner tube traps back in a few days.

I am the person who borrowed Al's tube traps. I've been curious to try these for quite some time as Al had told me that the sense of depth in his soundstage increased dramatically when he bought them. While I wouldn't refer to my soundstage as 'flat', it has nowhere the amount of depth that I have heard in some systems, including Al's.

I was also curious to hear what they would do the tonal balance. My room, unlike Al's, is quite open (especially on the left side where it opens to a kitchen) and I struggle to have enough mid-bass so that the presentation has weight. Knowing that the 16" tube traps would affect the midbass more than deep bass, I knew there was the potential to make the presentation sound leaner.

Well, the tube traps definitely affected the midbass. Overall the presentation has more clarity, but at the expense of sounding thinner and smaller (the latter seems to correlate with Al's findings that the absence of the tube traps made images larger).

My overall impression is that my system is better off without them, but only because my room is open - otherwise I have no doubt that tube traps would be important to achieving clarity in the lower midrange and bass.

I have a few more days to experiment (which I intend to do) and look forward to getting Al's impressions when he hears my system with his traps.

 

[Al M.]

I am the person who borrowed Al's tube traps. I've been curious to try these for quite some time as Al had told me that the sense of depth in his soundstage increased dramatically when he bought them. While I wouldn't refer to my soundstage as 'flat', it has nowhere the amount of depth that I have heard in some systems, including Al's.

I was also curious to hear what they would do the tonal balance. My room, unlike Al's, is quite open (especially on the left side where it opens to a kitchen) and I struggle to have enough mid-bass so that the presentation has weight. Knowing that the 16" tube traps would affect the midbass more than deep bass, I knew there was the potential to make the presentation sound leaner.

Well, the tube traps definitely affected the midbass. Overall the presentation has more clarity, but at the expense of sounding thinner and smaller (the latter seems to correlate with Al's findings that the absence of the tube traps made images larger).

My overall impression is that my system is better off without them, but only because my room is open - otherwise I have no doubt that tube traps would be important to achieving clarity in the lower midrange and bass.

I have a few more days to experiment (which I intend to do) and look forward to getting Al's impressions when he hears my system with his traps.

Interesting, Ian. I also look forward to hear your system with the traps. When I said images are larger, then only individual sound images within a soundstage that does not change in size. Does your soundstage as a whole also shrink? How is the effect of the tube traps on depth?

I agree that the effect of acoustic treatment will be greatly influenced by room layout. Yet in the case of my room it is now clearer than ever that the acoustic treatment is responsible for a lot of the 'magic'.

You are probably right that it is your open room that allows for the great mid-bass that you have, also without tube traps.

 

[Mike Lavigne]

Al,

I can really relate to the concept of 'before' and 'after' acoustically. starting last February, a year ago, I've been tuning my room for a full year. for the first 6 months it was mostly to do with treating reflections with wall treatments. also; I added some window inserts as you mention.....which solidified the soundstage.

http://www.whatsbestforum.com/showthread.php?17389-almost-free-and-4-inches-the-final-1

I also closed up a ceiling bass trap last August with the help of my son.

http://www.whatsbestforum.com/showthread.php?18116-suck-out-fixed-i-think

and then most recently I changed out my duplex outlets and the plugs on my power cords.

http://www.whatsbestforum.com/showt...7-Furutech-GTX-D-NFC-(R)-outlets-this-morning

so when you say that these things matter; I wholeheartedly agree. looking at your before and after pictures I can easily imagine what is happening.

 

[Andrew Stenhouse]

Gosh that is positive report Al & Mike.

I'm a big fan of targeted intervention - that is designing treatment to a room following sweeps. My own view, and it just my opinion, is that if you treat room without knowing what it is you are treating and why, there is the risk of a negative impact on other aspects by application of broad effect treatments - eg you could potentially over dampen a room by placing too much treatment in a room that is for instance acoustically fairly flat to begin with.

I like a fairly "live" room but one with thick carpet and lots of comfy furniture (dense foam is ideal). "Slap" echo I tolerate in small measure. I HATE bass nodes. You know the 40-80Hz "drone" that takes out everything else.

For my part if I have an obvious room node, or am unhappy about the balance I have in my sound, I get a well known local acoustician to pop over, conduct some sweeps, interpret the results (which is where the real skill is) and recommend the treatment to deal with the issue.

So for instance in the past I have had eg two nodes at 80-120 Hz originating from one corner and a hall-way passage, and he prescribed two flat panel designed tuned Helmhotz resonators to deal with the issue, and told me where to put them, which I did and most effectively. best $1200 I spent. On other occasions I have had suggested two broad spectrum bass traps for 40-60 Hz bass related issues.

I liken acoustic intervention in a room without knowing why and what for, to gardening blindfolded with a shovel - you might get the weeds, but you'll probably take out some of your flower beds as well. Sometimes however you will get really lucky and miss the flowers completely and just remove the weeds.

Now all that said, I am very happy you report a positive outcome to your intervention Al, and the ASC room treatments approach of recommending treatments tailored to a room based on a room's dimensions is a very solid way to proceed, all things being equal.

@ Mike - are you targeting your intervention?

Certainly with problem individual rooms, particularly those with audible issues, acoustic treatment is in my respectful opinion of fundamental importance.

Thanks for sharing.

 

[Al M.]

Al,

I can really relate to the concept of 'before' and 'after' acoustically. starting last February, a year ago, I've been tuning my room for a full year. for the first 6 months it was mostly to do with treating reflections with wall treatments. also; I added some window inserts as you mention.....which solidified the soundstage.

http://www.whatsbestforum.com/showthread.php?17389-almost-free-and-4-inches-the-final-1

I also closed up a ceiling bass trap last August with the help of my son.

http://www.whatsbestforum.com/showthread.php?18116-suck-out-fixed-i-think

and then most recently I changed out my duplex outlets and the plugs on my power cords.

http://www.whatsbestforum.com/showt...7-Furutech-GTX-D-NFC-(R)-outlets-this-morning

so when you say that these things matter; I wholeheartedly agree. looking at your before and after pictures I can easily imagine what is happening.

Wow, what a great room, Mike!

Yes, given your extensive experience with room treatment I would think you could imagine the effects in my room.

 

[Al M.]

I'm a big fan of targeted intervention - that is designing treatment to a room following sweeps. My own view, and it just my opinion, is that if you treat room without knowing what it is you are treating and why, there is the risk of a negative impact on other aspects by application of broad effect treatments - eg you could potentially over dampen a room by placing too much treatment in a room that is for instance acoustically fairly flat to begin with.

[…]

Now all that said, I am very happy you report a positive outcome to your intervention Al, and the ASC room treatments approach of recommending treatments tailored to a room based on a room's dimensions is a very solid way to proceed, all things being equal.

Yes, you could over dampen a room. This did not happen with the tube traps, but did happen after all my window plugs were installed. Removal of a couch in the back of the room (courtesy of Peter A.'s astute advice) solved the problem. Now the acoustics are fantastic; people hearing the room tend to get jealous .

I agree that the ASC approach of recommending treatments tailored to a room based on a room's dimensions is a very solid way to proceed. This had been done in my case as well, with room pictures and dimensions sent to ASC beforehand. In fact, they made sure to err on the cautious side (at that time I hadn't had any plans for window plugs yet which made a profound positive difference as well, see my system thread).

 

[FrantzM]

Hi

Just dabbing there and bolting out if asked for. That is why measurements should be taken when venturing in acoustic treatments. It would have given you some clues about what and where your problems might be. Measure before and after. It is not very difficult but does require some time to understand and become comfortable with the procedures and results. Or you could have had a friend who knows how perform some measurements of your room.
Then the placement of the traps would have been more straightforward: Where you place them has a great impact on the final results. It can be done by ears to a point but such method is at best a crapshoot. Once you are comfortable or satisfied with what you measured then the final tuning would be conducted by ear
Yes! using traps and similar things will make a difference but measuring what needs to be corrected brings in my exerience and IMHO better and more reliable results.

 

[Al M.]

Hi

Just dabbing there and bolting out if asked for. That is why measurements should be taken when venturing in acoustic treatments. It would have given you some clues about what and where your problems might be. Measure before and after. It is not very difficult but does require some time to understand and become comfortable with the procedures and results. Or you could have had a friend who knows how perform some measurements of your room.
Then the placement of the traps would have been more straightforward: Where you place them has a great impact on the final results. It can be done by ears to a point but such method is at best a crapshoot. Once you are comfortable or satisfied with what you measured then the final tuning would be conducted by ear
Yes! using traps and similar things will make a difference but measuring what needs to be corrected brings in my exerience and IMHO better and more reliable results.

Actually, at least in a room like mine, where you put the tube traps in a basic set-up is straightforward physics. They should be put in the corners behind the speakers,

http://www.asc-hifi.com/tube-trap-userguide.htm
(explanation there)

and I have an extra column of two stacked columns in the middle for centering imaging, at the first reflection point behind the speakers. Measurements are not needed for this straightforward configuration, the physics of which are explained in the ASC link.

If you would want to place additional tube traps, then perhaps measurements would be useful as to the precise placement.

In an open room like Ian's, measurements certainly would also be useful.

 

[Andrew Stenhouse]

Al, I reckon the ASC approach is really valuable. I know the first thing my acoustician does when I ask him over to measure a new room is ask me for my room dimensions, photo's and what speakers I am using. He can fairly easily predict what is happening and where it will come from just on that information. It gets trickier, as Ian experienced, when you have a room that is open plan, or opens out onto other space.

It is interesting that the window dampers, when combined with a couch, just tipped you over the edge.

Congratulations on getting that ever elusive "3D" sound stage we all want, it is a tough nut to crack. Can I ask - did you have to change your speaker position much +/- the tube traps? I often find a subtle adjustment to my speakers to be beneficial for tuning. Although not so much with my 30.1's - you can pretty much plonk them anywhere and they will sound pretty decent. Unfussy. Easy to get to sound good, really hard to get to sound great.

Happy hi fi mate.

Edit: I should add that I can't be bothered buying the kit to measure my room and have little interest in interpreting waterfall graphs so happily find the best acoustician I can and pay him whatever he wants to do his job. My view FWIW is I can't hope to have the experience and knowledge set of a professional, nor do I necessarily want it (hey my brain isn't very large and is full enough thank you) so am more than happy to pay someone to pop over, spend an hour or two, watch him do their thing and learn something along the way. I have always taken his recommendations, which sometimes has as it precursors - "you can make a small difference here but not alot' or "how does your wife feel about 6 foot bass traps?"

Interesting there are some rooms of friends he just has said - 'forget it - nothing you do short of rebuilding it will make any meaningful difference: don't waste your money'. Sometimes you are just stuck with what you have.

I know he says everything is a trade off, and if you cure something, quiet often you can inadvertently cause something else to act up, and so, if you don't know what you are doing, you can end up chasing your tail. Anyway that is all above my pay-grade - I leave it to the experts.

I know if I ever come into some money, and can build a dedicated listening room, I'll be flying him to wherever it is I am, to consult on the project. Much like Mike I think did with his build. Which I followed with much interest both on Audiogon and here.

Again congratulations Al; I am more than a little jealous

 

[BruceD]

Excellent and informative Posting Al-- Kudos on the treatment that made positive difference .Yes the ASC dudes are very helpful, I have dedicated room Trapped to their specs and been happy customer for 26 years.

--I would not own a Hi end system without them now-guess they are part of my setup not to be without-ha!

If anyone wants to try their system--you download a Test tone(s) File from their site --record it and send the WAV/ FLAC to them and they will give you their comments

Over to you if you implement or not.

As I stated above --I am happy with mine

Good Listening,

BruceD

 

[Frank750]

I've got 34 of them in my room including 4-20" rounds and 14-16" rounds. I've had them for many years but I'm still amazed at the difference just turning 2 of them from the reflective side to the absorptive side can make in the room.
I've experimented with them a lot over the years and still find myself trying different configurations on occasion.
I've even emptied the room of them once or twice but that only lasts a couple of minutes as I can't imagine living without them at this point.

I'll never have the fantastic purpose built room that Mike has but tube traps can turn a run of the mill room like mine into a great sounding environment for a relatively reasonable cost.

 

[Mike Lavigne]

Gosh that is positive report Al & Mike.

I'm a big fan of targeted intervention - that is designing treatment to a room following sweeps. My own view, and it just my opinion, is that if you treat room without knowing what it is you are treating and why, there is the risk of a negative impact on other aspects by application of broad effect treatments - eg you could potentially over dampen a room by placing too much treatment in a room that is for instance acoustically fairly flat to begin with.

I like a fairly "live" room but one with thick carpet and lots of comfy furniture (dense foam is ideal). "Slap" echo I tolerate in small measure. I HATE bass nodes. You know the 40-80Hz "drone" that takes out everything else.

For my part if I have an obvious room node, or am unhappy about the balance I have in my sound, I get a well known local acoustician to pop over, conduct some sweeps, interpret the results (which is where the real skill is) and recommend the treatment to deal with the issue.

So for instance in the past I have had eg two nodes at 80-120 Hz originating from one corner and a hall-way passage, and he prescribed two flat panel designed tuned Helmhotz resonators to deal with the issue, and told me where to put them, which I did and most effectively. best $1200 I spent. On other occasions I have had suggested two broad spectrum bass traps for 40-60 Hz bass related issues.

I liken acoustic intervention in a room without knowing why and what for, to gardening blindfolded with a shovel - you might get the weeds, but you'll probably take out some of your flower beds as well. Sometimes however you will get really lucky and miss the flowers completely and just remove the weeds.

Now all that said, I am very happy you report a positive outcome to your intervention Al, and the ASC room treatments approach of recommending treatments tailored to a room based on a room's dimensions is a very solid way to proceed, all things being equal.

@ Mike - are you targeting your intervention?

Certainly with problem individual rooms, particularly those with audible issues, acoustic treatment is in my respectful opinion of fundamental importance.

Thanks for sharing.

no....and yes.

basically; I spent hours and hours and hours over a 6 month period chasing reflective issues. I would add cloth treatment, then listen for a time. then add more, then listen; then add more, then listen. then remove some; then listen. as so on. my room is very, very live. I have a solid wood over concrete floor at the speaker end and all the surfaces in my room are hardwood cabinetry. which is great for energy retention but reflective glare can be overwhelming. I have lots of built in diffusion which for years I assumed dealt with that glare. but.........I did come up with a sonic reference in my mind that I was able to use to lead me toward where I wanted to get to. and finally I got there.

measure? not for me. I'm not against it. but not interested in that process.

after I dealt with the reflective issues; the next thing was the bass issues related to the ceiling trap. and then readjusting the bass tower adjustments. the link I posted above has much more information about that. but suffice it to say that maybe in my audiophile experience the most satisfying thing I've yet done is being able to adjust those towers by ear. until this last year I was afraid of that. now I'm confident about it. it is spot on. the larger the scale, and more complicated and dynamically challenging the music, the more at ease and natural it sounds. it's so much fun.

finally a few weeks ago I had those Furutech power cord plugs for my mono blocks changed and had some brightness from that. it bothered me some until I realized I could adjust the crossover. 10 minutes later problem solved. in the past I would never have considered that.

feedback from visitors from all my changes has been over-the-top positive. I'm happy.

so targeted intervention....yes....with my personal music reference....not measurements.

 

[steve williams]

Great feeling I bet Mike


Congrsts. Have you made more changes since our visit in April

 

[Mike Lavigne]

Great feeling I bet Mike


Congrsts. Have you made more changes since our visit in April

as I mentioned; I spent 6 months just working on the reflective issues. your visit was 1/3rd through that process. so I spent another 4 months working on more refinements after (you) the Trios Amigo's left.

when that was completed in I then worked on the ceiling bass traps, then took a few months (August-November) playing with the bass tower adjustments and getting them dialed in.

then this past couple of months did the duplex outlets and power cord plugs.

so yes.....many more changes since your visit.

 

[Andrew Stenhouse]

no....and yes.

basically; I spent hours and hours and hours over a 6 month period chasing reflective issues. I would add cloth treatment, then listen for a time. then add more, then listen; then add more, then listen. then remove some; then listen. as so on. my room is very, very live. I have a solid wood over concrete floor at the speaker end and all the surfaces in my room are hardwood cabinetry. which is great for energy retention but reflective glare can be overwhelming. I have lots of built in diffusion which for years I assumed dealt with that glare. but.........I did come up with a sonic reference in my mind that I was able to use to lead me toward where I wanted to get to. and finally I got there.

measure? not for me. I'm not against it. but not interested in that process.

after I dealt with the reflective issues; the next thing was the bass issues related to the ceiling trap. and then readjusting the bass tower adjustments. the link I posted above has much more information about that. but suffice it to say that maybe in my audiophile experience the most satisfying thing I've yet done is being able to adjust those towers by ear. until this last year I was afraid of that. now I'm confident about it. it is spot on. the larger the scale, and more complicated and dynamically challenging the music, the more at ease and natural it sounds. it's so much fun.

finally a few weeks ago I had those Furutech power cord plugs for my mono blocks changed and had some brightness from that. it bothered me some until I realized I could adjust the crossover. 10 minutes later problem solved. in the past I would never have considered that.

feedback from visitors from all my changes has been over-the-top positive. I'm happy.

so targeted intervention....yes....with my personal music reference....not measurements.

Thanks for the reply Mike - you are a braver soul than me! I would end up chasing my tail - I am sure.

I wondered why you didn't carpet your room with thick underlay when I first saw it. Now I understand.

I personally prefer a live room to an over damped one, but tuning it to remove the glare and room slap can be a tad painful. I have a friend who when he extended his listening room put in dampening material behind the wall coverings - it absolutely killed his system - sounded flat as a pancake. He took it all out, except for some at the first reflection points. Boy, what a difference. His bass nodes he built some tube traps for and like you, experimented with how much absorption he was happy with. Took him about 3-4 months of weekends to adjust to his musical tastes and speakers, but the result is now spectacular. It scales just beautifully. Much like your experience I wager

Isn't it marvellous there is always something to tinker with.

 

[steve williams]

Once Ron is ready to pay you guys a visit I told him I'd like to come along as well if that's ok.

 

[Andrew Stenhouse]

I should add I'm really fortunate with our apartment - render over double brick construction, concrete floors with double felt and thick carpet, 11-14 ft ceilings, and acoustically live but benign, with lots of irregular shapes and angles to break up the soundwaves.... My 30.1's don't excite much in the way of nodes and the soundstage is quite good. Imaging not so much - I have a double glass sliding doors down one side so you can't expect miracles with those. Mind you - I've never been to a classical concert yet with exact stereo imaging.

Sometimes you just get lucky.

EDIT: actually while I sit here enjoying my coffee, I have been musing about ceiling height, and how, particularly with choir or vocal music, high ceilings seem to help no end with a sense of "air". IIRC Mike has a "dome" ceiling - but Al. what height is your ceiling and is your room fairly regular dimension? I seem to remember it opened out onto a hall way?

 

[Al M.]

I've got 34 of them in my room including 4-20" rounds and 14-16" rounds. I've had them for many years but I'm still amazed at the difference just turning 2 of them from the reflective side to the absorptive side can make in the room.
I've experimented with them a lot over the years and still find myself trying different configurations on occasion.
I've even emptied the room of them once or twice but that only lasts a couple of minutes as I can't imagine living without them at this point.

I'll never have the fantastic purpose built room that Mike has but tube traps can turn a run of the mill room like mine into a great sounding environment for a relatively reasonable cost.

Wow, 34 tube traps. That's impressive Frank! You must have quite a large room.

 

[Mike Lavigne]

Once Ron is ready to pay you guys a visit I told him I'd like to come along as well if that's ok.

Steve, you are always welcome. it would be fun to get your views of the changes since you were here last year.