Nice to see that no matter how good and well-tuned a system such as yours is there is always the possibility of the unexpected. We truly are never done, are we?
almost free and 4 inches......the final 1%
- Thread starter Mike Lavigne
- Start date
There is no worse road to follow than one involving speakers and rooms. For every opinion, there are a hundred others. So I feel your pain.
I sorted through the maze and found the truth at the end for me. It goes something like this (hope to write an article on it one day):
1. Start with speakers. People tend to think the room is more important. It is only so in low frequencies. Once you get above the transition of a hundred hertz, it is the speaker that dominates. If the sound is harsh, voices wrong, etc., it is almost entirely due to speakers. From this article of mine, http://www.madronadigital.com/Library/Computer Optimization of Acoustics.html, you can see how that is true objectively:
These are three measurements taken at spots wider than 4 inches that Mike experienced. Yet, the frequency response is essentially identical once you get to a few hundred hertz.
2. Rooms naturally have reflections as do everyday places. Do your loved ones sound "wrong" because their voices are reflecting everywhere? Do they even sound different let alone profoundly different when you move from room to room and still hear their voices? Answer is no. The cognitive part of the brain filters out repetitive sounds coming at short delays. They are redundant. The adaptation is very quick measured in seconds. After that, you hardly "hear the room." In other words, reflections are not to be feared.
Forget what the logical part of your brain says with respect to sound bouncing everywhere and hence creating interference. It doesn't work that way. See this article for that: http://www.madronadigital.com/Library/RoomReflections.html
3. That is not to say that reflections don't change perception. They do. Sometimes they do it in a good way, sometimes in not so good way. The good way is side reflections. They help pull the sound out of the single spot of the speaker and spread it toward the side walls. Other than people mixing music and such, vast majority of people in blind tests will show preference for having these reflections. Data is in the above article.
This gets us back to the speaker. For the side reflections to do their job well, they have to sound the same as the direct sound or at least similar. Many speakers don't have this behavior and that is not good. This is why you want to pick the right speaker. The right speaker will have similar response on and off axis. And hence, the reflections become easy to analyze. Lousy speaker sprays lousy sound in non-direct axis and in doing so, makes you sit there screwing around with the room trying to reduce their impact. Much of what people think is room optimization, is dealing with less than performant speaker.
This has to be the high order bit in selecting the speaker. Ignore this and your acoustic life becomes miserable.
4. Below the transition frequencies of a few hundred hertz, the room dominates. It creates resonances that create peaks and nulls that create troughs. You must eliminate these as much as you can. Get a great speaker and deal with these in an otherwise ordinary room with furnishings and you are done! Yes, I said it. If you can tame the bass, and have a good speaker, the rest takes care of itself.
Fixing bass is done using placement of speakers, placement of your seating position, acoustic products or signal processing with or without multiple subwoofers. You can go back to this article, http://www.madronadigital.com/Library/Computer Optimization of Acoustics.html, to see why I am in the latter camp.
I can turn bass optimizations on and off and you would swear that the voices had become so much better. That stereo image had improved. And the walls of the room disappear. All without changing a thing in those domains. The perceptual effect is quite remarkable and why I consider this a mandatory thing to fix in your room. If you have not taken steps to mitigate bass response anomalies, you do not have a good sounding system let alone great. The physics and science of it will dictate that to be the case. And to know if you are there requires measurements. No amount of subjective listening will give you the data. This is pretty easy to do by the way although requires a weekend of work to learn the (free) tool.
5. Make sure your room is not too live or too dead. A modern room these days is full of harsh surfaces of wood and stone. This creates an overly live space. About 25% of the surfaces need to be absorbent and with thick material. If your room is too live then what Mike is saying is true: the ceiling is a good place to put absorption (or diffusion) as it adds nothing beneficial. Floor reflections are actually bad so you want to have a carpet with thick padding in front of you otherwise it will change the timbre. A living room with furnishings and a carpet is surprisingly close to ideal. It is an empty dedicated room that needs acoustic products if it lacks any other furnishings.
Before you spend a dollar on any of this, spend $43 and get this book: http://www.amazon.com/Sound-Reprodu...F8&qid=1430331308&sr=8-1&keywords=floyd+toole
With the primer I just provided, you should then be able to follow the material in there.
steve williams
Site Founder, Site Owner, Administrator
Bruce B
WBF Founding Member, Pro Audio Production Member
Bobvin,
You should refer you already have a system, describing it and your preferences - this will reduce the hundred other opinions referred by Amir to a few tens.
Just my 2 cents: Besides the excellent book referred by Amir, that is not a recipe book and will take considerable but well spent time to read, I appreciated the papers and articles by Art Noxon (the TubeTrap creator) that we can find at the tube trap site. http://www.tubetrap.com/tubetrap-art-noxon.htm. Even you do not want to use his products or follow his advice, you will learn a lot reading them.
They should. We stopped using our palms to check if we've got fevers a long time ago didn't we? That said I don't think people need to carry thermometers in their pockets 24/7 either. There's also a time when one should know that it's time to see a doctor. That includes times when you really feel sick but aren't running temperature!
hi Bob,
you would be most welcome to visit when you have the time....Portlandia is sooo close. my visitors last weekend were from Portland. we can talk about my process and cause and effect I've gone thru.
I sure like the idea of Mt. Hood to look at.
i'll expect that PM and we can go from there.....
Mike
They should. We stopped using our palms to check if we've got fevers a long time ago didn't we? That said I don't think people need to carry thermometers in their pockets 24/7 either. There's also a time when one should know that it's time to see a doctor. That includes times when you really feel sick but aren't running temperature!
no doubt measurements have their place. plenty of decisions related to my room are based on measurements.
but 'end game/finishing touches' for lots of (not all) music related things seem best done with ears....especially the validation part.
if it sounds bad it's bad no matter how it measures.
measuring can confirm something that sounds right; but it does not invalidate something that sounds right. I want both but will settle for one.
it's the sounding/hearing that matters.
we don't know enough to understand all the why's. and steady state test tones are a different beast than dynamic music.
Mike, did you notice something wrong with the sound from your old listening seat position and then decide to move your chair, or did you notice the distances did not form an equilateral triangle prompting you to adjust the chair position and then notice the sound was better? If it was the latter, then it would seem that measurements (or eyes) preceded the ears in this instance.
1-I've been using a seating position since I originally set up the MM7's 2 years ago that has remained the same. when I have visitors I always sight the seating position off my main towers and an outlet on the side wall so it is consistent as a switch chairs. I ended up there initially as the best spot to my ears after experimenting. looking back now and realizing the influence of the drop ceiling reflection I understand why it was my choice at the time.
2-Kevin Malmgren visited a year ago for 2 days and set the speakers up and positioned the listening position at the equilateral triangle position. when he left at some point I ended up moving it back to it's former spot. I do not recall a conscious logical reason why I did that, but assume I just preferred that, or from habit sighted the chair as I had before. the way things go sometimes. and I liked it just fine.
3-for a number of years I've thought about the whole 1st reflection issue as I described in the first post. I wondered whether there was an improvement to be had. likely what tipped me over was a visit to a friend who owned my same speakers and amps; although are rooms are quite different. there were things that I liked about it and things I did not care for. but it opened my eyes to the greater likelihood that something was holding back the optimal detail retrieval in my system.
4-so I did what I described in the first post, which was treating the first reflections methodically spot by spot, having a number of visitors for feedback, and then the final set of visitors who questioned the seating position. I investigated that and changed it to the equilateral spot and everything locked in.
I never had a sonic clue my seating position was not right. it was a result of a conversation with one visitor who while talking about the pursuit of the ultimate imaging questioned the seating position.
OTOH no doubt that my aural memory (of my friends similar system), what I was hearing in my system, combined with the visual view of my bare first reflection spots pushed me to action on the fabric treatments. I wanted to treat the spots but not cause another problem solving that problem. what tools did I have on hand to try it?
I hope that answers your question.
I will point out that until I solved the 1st reflection issue, the change of seating positions was never going to happen as that closer position had more extreme reflection issues. I suspect that is why I had reverted back to that spot after Kevin left but don't recall how my thinking went for sure.
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Bobvin,
You should refer you already have a system, describing it and your preferences - this will reduce the hundred other opinions referred by Amir to a few tens.
Just my 2 cents: Besides the excellent book referred by Amir, that is not a recipe book and will take considerable but well spent time to read, I appreciated the papers and articles by Art Noxon (the TubeTrap creator) that we can find at the tube trap site. http://www.tubetrap.com/tubetrap-art-noxon.htm. Even you do not want to use his products or follow his advice, you will learn a lot reading them.
Sorry, I should have included a link to my prior posts re: my room, gear. http://www.whatsbestforum.com/showthread.php?15727-Wilson-amp-ARC-for-me
I'll post updates on that thread, so as to not further hijack this one.
very good read and congratulations. thinking about it, i really need a similar success story in my own room which is moderately treated with with corner traps, some diffusers and furniture etc. ceilings are not treated at all save for 2 diffusers at first reflection points. I would appreciate some advice on inexpensive and visually unobtrusive materials to cover the ceiling with (so that I can see whether I can replicate mike's experience). i saw some textured wallpapers said to have various degrees of absorption/diffusion properties and I was curios to know if anyone had any experience with these or similar materials.
any fabric with a textured surface will work to treat 1st reflections. anything from grass cloth, to acoustic fabric you'd see over acoustic panels, to drapery fabric, or some sort of synthetic suede or velvet. you want to avoid anything too thick with a backing as that will absorb more frequencies. you are just wanting to knock down high frequency reflections without causing more change.
I went to a fabric store and paid $40 for 5 yards from their remnant section. not a big deal.
you are simply trying to experiment to find out cause and effect, so don't over think it. if you can find something that will blend visually into your décor then you can live with it longer or even permanently. I found that the easiest fabric to work with was synthetic velvet-suede, since it does not have long threads and so does not unravel on the edges once cut, cuts in a straight line, and sits flat on the wall and does not look wrinkled.
the hard part is getting the fabric to lay flat on the ceiling. I used a combination of double backed Velcro purchased from Home Depot (on the ceiling) and pushpins. along with some tacks. to use the tacks I had to hold the tack with a needlenose pliers with one hand and then tap it with a hammer with the other hand since all my surfaces are hardwood panels. if you have sheetrock then you can likely just push the pins or tacks right in without needing a hammer or pliers. on the walls I just hung the fabric and added a few tacks to keep it straight on the walls. if you glue the fabric that will change the reflective properties of the fabric. loose, hanging, fabric will reflect differently than attached fabric.....and the farther from the walls it hangs the more it will absorb. imagine a closet with lots of hanging clothes. you want the fabric to lay close to the surface.
sit in your listening chair and imagine all the spots where the geometry could result in 1st or second reflections. particularly note speakers reflecting off the opposite wall. notice where the ceiling or floor (particularly with hardwood or tile floors) intersects with the wall and it could then reflect right back to the listening position. you don't want to cover everything as that will simply deaden your room. and assume that your speakers will radiate sound in every direction. you will not know if it's an area causing a problem until you treat it and listen.
once you identify the problem areas then there are professional looking wall fabrics that can be installed and look right. but you don't want to spend that money until you know where you want it.
I've heard rooms with all the surface treated with fabric, or even drapery around all the walls. they have great imaging but to my ears are a bit lacking in energy and life. but in a small room sometimes that is the best approach. my goal was not to lose the attribute of high energy.
you can even hang fabric over your diffusion to see what happens.
there is no one way to do things.
I hope that helps.
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so Mike- after all of this, how do you think Chris Houston's plan was flawed from the beginning? its pretty stunning what you've been through over the past few years despite a pro acousticians white slate for your audio barn.
