Room Acoustics Question

[Clint Phare]

William: " I should watch being too pedantic. " What exactly is PEDANTIC?

[lynnm]

I will not risk being labelled as being preachy or teachy by attempting a comprehensive definition

Keep up the good work William F. Gil McDermott!

Y'All keep on Pendantin' ! I find your posts very informative and If I sometimes find you a little hard to follow - It's my job to figger it out "My own self" or to ask more questions.

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca. 1304 BCE)

[mace]

quote:

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Originally posted by William F. Gil McDermott:

3) The next "problem" seems to be what we are trying to measure when we test in a room with test equipment of many designs. This is not well identified.

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My main purpose in all of this was to see how my whole system responds, room and all. I suspected big issues with bass response, standing waves, reflections and general sonic nastiness before ever starting to generate frequency response curves to determine optimal speaker placement. I knew from the beginning that in no way shape or form would I be generating frequency response curves typical of the speakers alone. I never did suspect at all that the speakers are defective. I simply set out to optimize speaker placement. I now believe that speaker placement will only go so far to better the sound. To further optimize my room I believe I'd need to add sound absorbing panels to the walls.

quote:

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Originally posted by William F. Gil McDermott:

5) How about our hearing? Bob G. points out that early arriving reflections are the most damaging. This is not a bass issue, but is very important.

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This is a good question. I don't know how good my hearing is or exactly what role reflections and such play in what I hear. Sometimes at higher levels, like 95+ dB it seems like my sound stage just falls apart (sounds ragged, harsh) if everything is playing (bass, drums, guitar, vocals etc.). However, at these same sound levels, if just a simple drum line and a smooth solo guitar are playing it feels like I could melt into the music. I'm not sure if it is my hearing distorting for the former or just the room acoustics somehow making the sound very ragged.

quote:

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Originally posted by William F. Gil McDermott:

6) The above are all the product of very serious engineering studies. (Please appreciate why I'm not a fan of super wire upgrades. This acoustic stuff causes gross, measurable, anomalies in frequency and time response. Wire has none of these. Yet people go nuts over wire.)

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I tend to agree. After doing all this testing, I can't imagine wire making nearly as big a difference on the sound quality as the room and speaker position, as long as you don't use powdered metal wire or something... Of course, I haven't to upgraded my 12 year old monster cable. Each 25 ft. strand is very brown and oxidized along the entire length, no more bright orange copper color anywhere. Perhaps this is interfering with something at these higher output levels (of course, 95 dB is like 0.25 W or something with these KLF 30's...). I'll also mention for the record that my amp is rated at <0.03% THD at 0.25-40 W so I don't think that's the problem.

quote:

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Originally posted by William F. Gil McDermott:

7) The issue at the beginning was (if I may be presumptuous about anyone's thought processes), (a) "I want to test my set-up at my listening position to determine whether it is good or bad." (

"Now that I have the test results, does the data tell me something about whether it is good or bad?" And ©, "If I can identify what is good and bad, how do I make it better?"

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That's pretty much it. I'd sum it up as (a) This seems like it should sound better so ( I'll take some data and see if I can adjust speaker placement to do just that.

quote:

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Originally posted by William F. Gil McDermott:

8) I've been wrong to suggest that something a step or two up from a frequency generator and an RS meter is going to give a solid answer to (a), (

or ©. The most gifted engineers with the most sophisticated test equipment look for the answers.

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At this point I need more data.. Data for me is hard to get since it takes time and this little project doesn't have the highest priority. I'd really like to get ahold of a test CD so I wouldn't have to run back in forth in the room changing pitch and reading levels.

quote:

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Originally posted by William F. Gil McDermott:

9) The room is definitely the problem. Please note that the movie theater industry wants what is essentially the listener in an anechoic chamber with very well controlled directional speakers. Unfortunately, we don't have that at home. The horns can do some of it thought.

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Agreed about the room!

Gil: Thanks for all the input. It is very much appreciated. If I didn't reply to a certain point it's because I agreed with it and didn't have anything further to say!

Sounddog: That software would be interesting but somehow I have my doubts about it's effectiveness. There are just so many variables when one examines room acoustics in someone's living room I'd be suspicious that the software would take all that is necessary into account. Although, to be honest, I have no experience with such software, perhaps it would surprise me at doing a good job.

More later,

Mace

This message has been edited by mace on 12-29-2001 at 10:13 PM

[soundog]

I've heard the improvements these devices can make in CDs and Speakers. Both are very significant. They are yet to demonstrate their room correction software and measurement kits so we'll see.

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Soundog's HT Systems