Object of room treatments and equalization.

[Alex2507]

I understood the object of all this to be getting a flat line at around 75bd from around 20hz to 20,000hz with pink noise being pumped out of my receiver.

A friend of mine says that that is where you start and from there you go on to adjust the EQ to make the recording suit your own listening preferences. Listening preferences would vary from person to person and from recording to recording and from day to day. Quite a set of variables if you ask me. There was also talk of what recording engineers do and how they intend for us to listen to recordings.

My take on it was that if you do get a flat response in your room then all the frequencies are reproduced at matched volume at which you would be able to hear what the recording engineer actually intended for you to hear.

I would like a little clarification for my own purposes, not to argue with.

 

[Bloodstriker]

I'm still new at this, but from my understanding, flat response is the end goal. EQ is to get rid of any peaks that the room treatments couldn't fix.

 

[TLS Guy]

I understood the object of all this to be getting a flat line at around 75bd from around 20hz to 20,000hz with pink noise being pumped out of my receiver.

A friend of mine says that that is where you start and from there you go on to adjust the EQ to make the recording suit your own listening preferences. Listening preferences would vary from person to person and from recording to recording and from day to day. Quite a set of variables if you ask me. There was also talk of what recording engineers do and how they intend for us to listen to recordings.

My take on it was that if you do get a flat response in your room then all the frequencies are reproduced at matched volume at which you would be able to hear what the recording engineer actually intended for you to hear.

I would like a little clarification for my own purposes, not to argue with.

That's the direct route to lousy sound, speaker damage and bottoming sub drivers.

 

[trnqk7]

What do you suggest then TLS? I don't think that "flat" response sounds very good, personally. But what ideas to you have to help the OP out? I'm curious as well to get ideas on how to make my setup sound better.

 

[Alex2507]

That's the direct route to lousy sound, speaker damage and bottoming sub drivers.

That confused me. What is the direct route, his approach or mine?

 

[trnqk7]

I would like to hear some suggestions on treating a room outside of acoustic paneling and bass traps...my wife would never allow that stuff in the living room (in a dedicated theater room, it would be fair game). So are things like drapes/curtains, wall hangings, carpeted floors and soft furniture the best/only things to do otherwise?

 

[bpape]

There are things you can do in a room to improve performance. Proper seating position being the most important. Curtains and rugs can minimize objectionable echo but are upper mid/high frequency only devices. Stuffed chairs, ottomans, canvas paintings over wood frames stuffed with insulation, etc. can all be used and 'invisible' treatments.

As to the OP - flat response is the goal. You can EQ a little to tame the last few nasties that proper setup and treatment can't finish - but it will do nothing to fix decay time issues. EQ'ing to make up for inadequacies in equipment or setup is truly a disaster waiting to happen. Hyping bottom end and highs is pushing equipment and speakers harder.

If you want something that has exaggerated bottom end, sit next to a wall and don't treat the room - or buy speakers that have that tonal character. If you want to hear what the engineer laid down, then shoot for relatively flat response.

EQ CAN be used to lightly tailor the response to more suit your taste. Lightly being the key word here. A couple db here and there will be fine but IMO is something that you set once and forget. Now, if you have an EQ that will allow several different memories as you're an old fogie like me with a bunch of old rock'n'roll albums that need a bit of help on the bottom, then one of those memories might be the trick.

Never the less, the starting point is flat.

Bryan

 

[TLS Guy]

What do you suggest then TLS? I don't think that "flat" response sounds very good, personally. But what ideas to you have to help the OP out? I'm curious as well to get ideas on how to make my setup sound better.

I knew this would heat things up. I should by now know when to keep those quips to myself.

However sometimes a thread opens up to a great misunderstanding in audio, and an area rife with error. This is one such.

The area hinges on the huge misunderstanding of what speakers are capable of and their severe limitations. Really the route to good audio is the sum of compromises, and not inadvertently going down a train of thought where you end up precisely wrong.

Lets look at this another way. If you had a group of one to four good instrumentalists with acoustic instruments in most of the members listening rooms, it would sound darn good. Now if that performance was recorded with fine studio microphones handled with intelligence, than when played back it should still sound good. I'm sorry to have to tell you the speakers that will rise to that challenge are far and few between.

During my 30 odd years in Grand Forks, I have had the opportunity do do just that for UND student audition tapes etc.

Now all the room reflections etc. are going to upset a flat room response to a degree. However the live performance is going to sound right in all but the oddest of rooms.

So if your speaker is lacking, is Eq the answer. Used intelligently with a good pair of ear lobes, it can help. However my experience tells me you can never completely correct a speaker that is wanting.

Now frequency response errors in speakers are usually accompanied by other problems in the region of the errors. These include but not limited dispersion problems distortion, phase and time delay problems.

The other problem is the power response of the speaker. This is especially true in the bass. Every time you correct by 3db you are doubling the power required of the speaker at that frequency. Now a ported speaker completely decouples from the air rapidly below system resonance. If you Eq, all you produce is distortion, frequency doubling and the high chance of driver damage due to excessive cone excursion.

If your measuring records some aberration in the HF, tweeter overload and burnout are risked.

Unless you are very skilled, and have invested in good test gear and have the skill to use it, then Eq by ear with a thoughtful subtle touch is the best way to go. By that I mean one to three db cuts or boosts here or there. I have NEVER seen more drastic Eq than that do anything but harm.

The next issue, is the thorny matter if integrating speaker and sub. Now for movies the standard Lucas approach is I suppose fair enough. I don't buy that you can have a limited pair of speakers and turn them into fantastic audio reproducers by the addition of a sub.

My view is that Joe Schmoe is not all wrong if you have followed some of his threads. Far from it!

Really, having a good pair of left right speakers that stand on their own merits is the very foundation of a good audio system, in my view. If they can't by themselves produce a believable satisfying sound stage without the temptation to tinker, then you are off to a bad start and have an up hill, if not impossible, climb.

Really I think the best results from an audio point of view is having a set of speakers that gives a very satisfying result full range and gently extending their range with a sub of comparable quality. This of course done with intelligence and subtlety. As I have said before sub to speaker is a crossover with ALL the ills that entails. Minimizing the chance for error in regions in which the ear is sensitive is a good plan.

And then we haven't mentioned the center speaker, but I have posted on this before. As I have said before the center speaker and getting it right is perhaps the toughest challenge confronting the speaker designer.

 

[trnqk7]

TLS-this wasn't to heat things up. I legitimately wanted to know what your thoughts were. You did leave a "quip" but I knew there had to be more behind it. The quip does not do any of us any good if you don't back it up with something-which you have now done. Thank you.

 

[Alex2507]

This is funny: my friend actually said it would be good to increase both treble and bass controls ( I don't have an EQ ) in some cases and have the frequency response graph look like a sine wave.

I just leave my treble and bass set to 0 because I currently don't have any way to measure the frequency response in my room.

 

[trnqk7]

I would agree with TLS on this-adjusting them very much would not be a very good idea...but some tweaking shouldn't hurt. Just remember the 3db increase = 2x power needed at those frequencies. You can only "push" so much before something has to give-either amp or speaker and sound quality will suffer as result in either case. Equipment damage could be possible in extreme cases.

 

[TLS Guy]

TLS-this wasn't to heat things up. I legitimately wanted to know what your thoughts were. You did leave a "quip" but I knew there had to be more behind it. The quip does not do any of us any good if you don't back it up with something-which you have now done. Thank you.

I know! It's real work putting these type of posts together. A quip is a good way of gaging interest and stimulating it. I hope I'm forgiven.

 

[trnqk7]

undoubtedly

 

[jaxvon]

The purpose of room treatment is to control the acoustics of the room. With treatment, you can control the dispersion from your speakers and the consequent reflections. This will allow you to achieve the optimum environment for your speakers. The EQ is to fix and anomalies that result from a speaker's shortcomings. This could be taming peaks in response, or boosting small nulls. The bass response will have to be hashed out with positioning and bass traps. Used properly together, room treatment and EQ can create the ultimate listening experience.

 

[TLS Guy]

The purpose of room treatment is to control the acoustics of the room. With treatment, you can control the dispersion from your speakers and the consequent reflections. This will allow you to achieve the optimum environment for your speakers. The EQ is to fix and anomalies that result from a speaker's shortcomings. This could be taming peaks in response, or boosting small nulls. The bass response will have to be hashed out with positioning and bass traps. Used properly together, room treatment and EQ can create the ultimate listening experience.

Well a lot of people don't like plastering objects over their elegant listening spaces. I just don't believe good speakers require it. This is my approach to room acoustics.

First of all if I have the luxury, I set the room dimensions correctly. Next I have found over dead rooms to be poor listening rooms. I think what is required is randomness, and the more random the better. I go out of my way to encourage random reflection. Now it is dominant reflections that are not random that are the problem.
In that regard ceilings and floors are a particular problem, especially ceilings. It is hard to chop up ceilings in most rooms, without going over the top with WAF, and especially my architect/interior designer daughter. I deal with this by limiting the vertical dispersion of my speakers, not the horizontal.
The floor is a problem because of first reflections from low placed LF drivers. Carpet, especially wool carpets take care of this.
Now for the side walls I encourage as much random reflection as possible. In that regard, I make use of pictures and windows.
How. Well when I remodeled this house, I enlarged the windows, added one and changed an all metal door for metal door with a large glass window. I placed a couple of of pictures close to the left and right fronts. The TV is obviously a reflective surface. There are glass doors on the turntable case are close to the left rear back speaker, and another window on the right opposite. Now the left side of studio is potentially problematic, but the entry door is close to the left of the left front speaker. This is a solid core oak door. It definitely sounds better with the door closed, and not just from bass leakage issues either. However all the equipment on the left wall has lots of irregularly reflecting objects!
This all adds up to a space that is pleasant and relaxing with marvelous views. And the great thing about it all, it sounds wonderful. The other issue is speaker voicing. I, and I think all good speaker designers, do final voicing by ear. These speakers are not going anywhere for a while I hope. So I have to suspect that doing final voicing in this space has something to do with the good end result.
Now the next thing, is things happen you can't explain. My lower level living room is such a case. I did no acoustic planning about this what ever! It has sound arriving after the Haas effect, in other words an echo. These pictures were taken by my architect son in law. Yes, married to my architect daughter.

http://mdcarter.smugmug.com/gallery/2467814#129438328

Now a little more furniture has been added since these pictures were taken. That little system sounds absolutely marvelous in the space! It is even great if I sit by the fireplace toasting my feet way left of the left speaker. And darn it, sounds even localize between the speakers that far out in left field. Now even I thought that space was likely to be a hopeless case, but far from it! The floor is not even carpeted in front of the speakers. I think it is that irregular reflection again. The only thing I did notice about the space before installation, was that it was a nice room to sing in. I really felt the room reinforcing my voice and could hold pitch easily. It was a room that gave a singer good feedback. I would love to have the chance to record a small instrumental group in the space. Now I bet if I started to muck about with room treatment I would ruin it. Now that whole experience was unplanned and an unexpected delight.

I'm going to change gears and get onto the topic of center channel speakers. My father always wanting to push the curve wanted a multichannel system many years ago, before Dolby 5.1. I visit at least once a year. The center channel I found to be a particular problem. I think because in most rooms (12 to 14ft) the center speaker is too close to the left and right for comfort. After a lot of experimenting and thinking about the problem, I concluded that the center speaker interferes with the left and rights, causing comb filtering problems. I found that a focused HF dispersion was preferable. I found this to be an ideal application for a coaxial driver, where the cone can act a waveguide to the tweeter. I really believe this to be valid observation. I'm really bothered by the effects of the center channel in most systems. The other thing is that the 1db steps for level in the set up menus is too great. I found I was always going back and forth db. I finally added a pot from the preamp output to the center channel crossover. I set it with my Shure SM 80 condenser mic. I have not changed the level since. Even a fraction of a db too loud on the center channel completely destroys the acoustic perspective.

I just don't believe that in the vast majority of rooms good speakers need funny objects placed in the room and peculiar sculptures hung from the walls. Mine certainly don't.

 

[Glenn Kuras]

The purpose of room treatment is to control the acoustics of the room. With treatment, you can control the dispersion from your speakers and the consequent reflections. This will allow you to achieve the optimum environment for your speakers. The EQ is to fix and anomalies that result from a speaker's shortcomings. This could be taming peaks in response, or boosting small nulls. The bass response will have to be hashed out with positioning and bass traps. Used properly together, room treatment and EQ can create the ultimate listening experience.

Very well said and pretty much RIGHT ON THE MONEY.


TLS Guy,
I think you would be pleasantly surprised if you where to pick up your system and put it in a properly treated room. Do you have any water fall plots you can post of your room?

Glenn

 

[TLS Guy]

Very well said and pretty much RIGHT ON THE MONEY.


TLS Guy,
I think you would be pleasantly surprised if you where to pick up your system and put it in a properly treated room. Do you have any water fall plots you can post of your room?

Glenn

NO! I have a nice smooth warm acoustic environment and a very natural sound stage well behind the plain of the speakers. It needs leaving well alone!

I posted this before on this topic.

Siegfried Linkowitz has just delivered a paper at CES (preprint 7162) titled Room Reflections Misunderstood. I have only seen this in abstract so far. He makes points that I have consistently made in these forums. His six impediments to creating a realistic impression of an acoustic event are.

1) Non uniform polar response.
2) Inadequate dynamic range.
3) Speakers too close together or asymetrically placed.
4) ROOM TREATMENT THAT CHANGES THE SPECTRAL BALANCE OF REFLECTED SOUND.
5) Room equalization above low frequencies.
6) Recordings with too many microphones in separate sonic spaces.

I could not agree more.

Now your room has just about perfect dimensions. As you describe your room you are unlikely to require room treatment, or have to equalize LF frequencies with superior speakers.

I have been chastised for this view, but I regard room treatments as a balm for serious speaker defects. I have done a lot of location recordings, and I monitored with speakers. Within reason good speakers give a good account of themselves in the most unpromising of acoustic environments.

 

[bpape]

Nobody said overdeaden it.

You can do dimensions till you're blue in the face and it WILL help SPREAD the modal activity out farther - but it doesn't eliminate it. It also does nothing to deal with decay times, ringing, nulls based on bad reflections, SBIR due to speaker/wall proximity, or reflections that are out of time and have different responses.

Are you aware that pretty much EVERY speaker has a completely different response curve at 45 degrees off axis than it does direct? Do you realize that this 45 degree off axis response is what's being reflected back at you to mix and muck up the direct sound in both the time domain and by causing a change in overall perceived response?

Also, the point you emphasized from Linkwitz does NOT say don't treat, it says don't use treatments that change the spectral balance of reflections. Hence, don't use cheesy thin foam, carpet, etc. or other things that only absorb highs and leave the rest of the reflections alone - thereby changing the balance.

Proper room treatment is used to minimize reflections that cause response anomolies and bring the decay time into the target range for a specific room volume and usage. Stuffed furniture and people are broadband absorbers, not just high freuqency ones.

Broadband absorbtion used judiciously will leave you with the same spacious feel, better imaging, better vocal definition, better detail recovery, tighter more controlled bottom end, etc.

One must determine the priority of the space. Is it to look like a normal room at the expense of ultimate performance, - or is it to have ultimate performance with the understanding that some visual compromises must be made. It's each individual's choice as to that decision. You seem to have picked the former which is your right - but you'll never know what the equipment you've purchased is truly capable of doing in a completely untreated space.

Personally, I'll take a carefully selected mid priced system in a properly treated space over an all out system in a poorly designed space.

Bryan

 

[TLS Guy]

You have an ax to grind. I'm not buying it. Literally! If speakers are putting, their ugly footprint over the performance, you can never disguise it, no matter what you do. In my book you will not make a poorer speaker sound better than a superior one with room treatment.

In my system I have no bass boom. The bass strings have just the right balance. You really have the detail and the players "digging in" in the rough and tumble. The tympani are tight and articulate perfectly and with great effect. The high strings are silky and not wiry, and that's tough for speakers. The brass is thrilling and, never strident. Single voices to massed choirs sound realistic. There is a natural believable balance and sound stage with fantastic depth. At the same time the spoken voice is clear and natural, with good clarity. Now why would I want to muck about with it and spoil mine and my daughter's interior design? If anything I would rather have a room a little on the live side than dead. I believe a lot of random reflections contribute to recreating the live performance.

 

[ParadigmDawg]

..................

You have an ax to grind. I'm not buying it. Literally! If speakers are putting, their ugly footprint over the performance, you can never disguise it, no matter what you do. In my book you will not make a poorer speaker sound better than a superior one with room treatment.

In my system I have no bass boom. The bass strings have just the right balance. You really have the detail and the players "digging in" in the rough and tumble. The tympani are tight and articulate perfectly and with great effect. The high strings are silky and not wiry, and that's tough for speakers. The brass is thrilling and, never strident. Single voices to massed choirs sound realistic. There is a natural believable balance and sound stage with fantastic depth. At the same time the spoken voice is clear and natural, with good clarity. Now why would I want to muck about with it and spoil mine and my daughter's interior design? If anything I would rather have a room a little on the live side than dead. I believe a lot of random reflections contribute to recreating the live performance.