Treating early reflections for ALL speakers?

[yepimonfire]

I'm aware the easiest way to find early reflection points is by having someone hold a mirror along the wall while I sit in the mlp, the issue is I don't have someone able or willing to do this, and a lot of the areas are difficult to reach. I know the ceiling/floor reflection points are halfway to the mlp, and I know that using the equation y*x"1"/x"2"+x"1" will give me the first reflection points for ground level speakers, so long as the tweeters are at ear level, but I'm not quite sure how to find the first reflection points for the bookshelves I have mounted to the ceiling as top middle atmos channels. Any suggestions?

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[speakerman39]

Here is an article that you may find useful. I found it to be very informative. One of these days down the road I plan to do some treatments as well. Just not near that stage yet. Anyways here is the article:

http://www.barrydiamentaudio.com/monitoring.htm


Cheers,

Phil

 

[shadyJ]

Here is an article that you may find useful. I found it to be very informative. One of these days down the road I plan to do some treatments as well. Just not near that stage yet. Anyways here is the article:

http://www.barrydiamentaudio.com/monitoring.htm


Cheers,

Phil

While the stuff about the golden ratio is generally good placement advice, the author didn't say why this is so (cancellation of probable dips by using surface bounces). But the author then goes on to say: "Ever notice how your playback system sounds better during the late night hours? One of the reasons for this is the AC coming from the wall outlet is cleaner when there is less usage." and continues along those lines. That isn't a guide I would recommend, especially to newcomers, it deals in some bad science.

Room treatments is about measurement, measurement, and measurement. You need to measure your system, and see what the problem areas are, than test some solutions with more measurements, until you get something that is better. By the way, elimination of reflections is not always desirable. Read Floyd Toole's "Loudspeakers and Rooms", you will not find a better starting point for acoustics in high-fidelity sound systems than that book.

 

[j_garcia]

Surround speakers, including overhead, are supposed to be diffuse, not 100% directional, so I would tend to say first reflection is less important to control for them, if even important at all.

 

[William Lemmerhirt]

Surround speakers, including overhead, are supposed to be diffuse, not 100% directional, so I would tend to say first reflection is less important to control for them, if even important at all.

I have to say, maybe not. Dolby recommends direct radiators for atmos, and also IME modern soundtracks have for a long time been discrete and benefited from accurate rear sound field imaging. I do agree with questioning if treatment of overheads, or even surrounds is worthwhile. I think even with fronts, people can tend to overdo the treatments. Shady made a good point of that.

 

[j_garcia]

I have to say, maybe not. Dolby recommends direct radiators for atmos, and also IME modern soundtracks have for a long time been discrete and benefited from accurate rear sound field imaging. I do agree with questioning if treatment of overheads, or even surrounds is worthwhile. I think even with fronts, people can tend to overdo the treatments. Shady made a good point of that.

The goal is not to shoot for anechoic. I use monopoles for my surrounds because I do not prefer my rear stage to sound diffuse. Real life has reflection and echoes, so eliminating them would not make sense to me, but it also depends on the listening environment. If it is "live" then you'll definitely benefit from some control, but as you mentioned, you don't need to go overboard. SOME of the surround activity is discrete, but there's also a lot of "presence" sound in them as well; so what you're listening to will cause the results to vary.

 

[shadyJ]

Once upon a time surround speakers were supposed to be diffuse, but no longer. 7.1 should have subdued that idea, and object oriented sound mixes should be the final nail in its coffin. Even the idea of diffuse surrounds was a point of disagreement among professionals when THX implemented them as a standard back in the 1980s. No one should still be making bipole or dipole surrounds. Their day is done, and it is questionable whether they should ever have made as much headway as a form factor for surrounds as they have.

 

[j_garcia]

IMHO, it started with matrix surrounds, where diffuse was what you got whether you wanted it or not and you were happy to have sound back there at all. Bi/dipoles never really should have existed as far as I am concerned.

 

[speakerman39]

While the stuff about the golden ratio is generally good placement advice, the author didn't say why this is so (cancellation of probable dips by using surface bounces). But the author then goes on to say: "Ever notice how your playback system sounds better during the late night hours? One of the reasons for this is the AC coming from the wall outlet is cleaner when there is less usage." and continues along those lines. That isn't a guide I would recommend, especially to newcomers, it deals in some bad science.

Room treatments is about measurement, measurement, and measurement. You need to measure your system, and see what the problem areas are, than test some solutions with more measurements, until you get something that is better. By the way, elimination of reflections is not always desirable. Read Floyd Toole's "Loudspeakers and Rooms", you will not find a better starting point for acoustics in high-fidelity sound systems than that book.

Yeah there are some things I am not in agreement with the author either. However, there is also some useful info. Just came across this a good while back and hung onto it. Thought it was a good time to share. HT is NOT my thing anyways. Never has been.


Cheers,

Phil

 

[William Lemmerhirt]

Well I can see we all agree on one thing. Bi/dipole speakers should never have come to be, lol. J_garcia, I must agree that results will vary based on implementation. Fwiw I'm a proponent of taking care to set up surround speakers to image between themselves and with the fronts to create a bubble. IMO this will allow for "presence" as you mentioned, and discrete info to be conveyed appropriately. I'm also ok with a little bit of a live sound.

 

[TLS Guy]

I'm aware the easiest way to find early reflection points is by having someone hold a mirror along the wall while I sit in the mlp, the issue is I don't have someone able or willing to do this, and a lot of the areas are difficult to reach. I know the ceiling/floor reflection points are halfway to the mlp, and I know that using the equation y*x"1"/x"2"+x"1" will give me the first reflection points for ground level speakers, so long as the tweeters are at ear level, but I'm not quite sure how to find the first reflection points for the bookshelves I have mounted to the ceiling as top middle atmos channels. Any suggestions?

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Most rooms do not need treatment. Reflections are a good thing and give the sound depth. There has been too much nonsense about killing reflections in the home environment. If truth be told most domestic spaces do not have enough reflections.

Again the problem is the all too common lousy speaker issue. Reflections are a problem for speakers whose off axis response does not mirror the axis response sufficiently. This is a common speaker defect. When this occurs then reflections are a problem. The problem though in that case is the speaker and not the reflections. Good speakers still sound very good in highly ambient spaces. Saul Linkwitz has made this very point often, and I totally agree with him.

There might be an issue here with pop and rock which is recorded really screwed up. So they isolate performers in padded boxes and then add reverb and lots of ridiculous effects. So I suspect when that mess is played back then it is a regular free for all.

 

[yepimonfire]

While the stuff about the golden ratio is generally good placement advice, the author didn't say why this is so (cancellation of probable dips by using surface bounces). But the author then goes on to say: "Ever notice how your playback system sounds better during the late night hours? One of the reasons for this is the AC coming from the wall outlet is cleaner when there is less usage." and continues along those lines. That isn't a guide I would recommend, especially to newcomers, it deals in some bad science.

Room treatments is about measurement, measurement, and measurement. You need to measure your system, and see what the problem areas are, than test some solutions with more measurements, until you get something that is better. By the way, elimination of reflections is not always desirable. Read Floyd Toole's "Loudspeakers and Rooms", you will not find a better starting point for acoustics in high-fidelity sound systems than that book.

Yeah I got some serious audiophool vibes from that site. Remember, George Cardas makes super expensive snake oil cables. The other issue I have with the site is the guy immediately starts suggesting placement along the side walls so you can spread the speakers farther apart. Anybody who had a basic grasp on acoustics will tell you side wall placement is the worst option for multiple reasons. Secondly the author never stated exactly how much channel separation you needs and why this necessitates side wall placement. Its generally recognized the front left and right speakers should form an equilateral triangle, +- 8°. Unless one has placed their home theater in a walk in closet, most front walls are wide enough to accommodate this.

There are simple established rules for speaker/listening position placement, such as the 38% rule, equilateral triangle, etc., all have a mathematical basis. No voodoo required.

I've already done the measuring, I don't have any low frequency problems, I'm +-5dB from 23hz-200hz, the main issue I have is poor imaging from reflections, the left side of my system sound much more prominent than the right side. Adjusting trim settings doesn't help, because its a frequency problem with the left side of the room accenting the high end. Its the worst among the front L/R speakers. Measuring the frequency response of the front L/R speakers gives me a -+6dB response from 23-16khz at 1/3 octave smoothing. My room has hardwood floors and bare walls. I have a large window on the right side of the room that I haven't decided how to treat yet. Not a fan of blackout sound reducing curtains, may attach some panels to a board and make a removable treatment that I can hang in front if the window.

I will try to take some pictures and measurements and post back here.

While the stuff about the golden ratio is generally good placement advice, the author didn't say why this is so (cancellation of probable dips by using surface bounces). But the author then goes on to say: "Ever notice how your playback system sounds better during the late night hours? One of the reasons for this is the AC coming from the wall outlet is cleaner when there is less usage." and continues along those lines. That isn't a guide I would recommend, especially to newcomers, it deals in some bad science.

Room treatments is about measurement, measurement, and measurement. You need to measure your system, and see what the problem areas are, than test some solutions with more measurements, until you get something that is better. By the way, elimination of reflections is not always desirable. Read Floyd Toole's "Loudspeakers and Rooms", you will not find a better starting point for acoustics in high-fidelity sound systems than that book.

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[William Lemmerhirt]

I know you've mentioned your dislike of room correction, but you might find Audyssey to be helpful in your room. Also, imo the equilateral triangle is overstated and should you end up there, it should be by experimentation. This is especially true if you add a center.

 

[yepimonfire]

Once upon a time surround speakers were supposed to be diffuse, but no longer. 7.1 should have subdued that idea, and object oriented sound mixes should be the final nail in its coffin. Even the idea of diffuse surrounds was a point of disagreement among professionals when THX implemented them as a standard back in the 1980s. No one should still be making bipole or dipole surrounds. Their day is done, and it is questionable whether they should ever have made as much headway as a form factor for surrounds as they have.

Diffuse surrounds only applied to the old Dolby Surround matrixing. Ever since discrete 5.1+ has come in to play its irrelevant. Surrounds are not just for ambient effects, lots of discrete information is routed to them, and they should be treated the same as the front L/R.

I laugh when people claim surrounds are unimportant and used only for ambiance. All you have to do is load a track extracted from an mkv into a DAW and see its pretty much just as active as the front L/R.

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[William Lemmerhirt]

I laugh when people claim surrounds are unimportant and used only for ambiance. All you have to do is load a track extracted from an mkv into a DAW and see its pretty much just as active as the front L/R.

Definitely agree with this.
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[yepimonfire]

Most rooms do not need treatment. Reflections are a good thing and give the sound depth. There has been too much nonsense about killing reflections in the home environment. If truth be told most domestic spaces do not have enough reflections.

Again the problem is the all too common lousy speaker issue. Reflections are a problem for speakers whose off axis response does not mirror the axis response sufficiently. This is a common speaker defect. When this occurs then reflections are a problem. The problem though in that case is the speaker and not the reflections. Good speakers still sound very good in highly ambient spaces. Saul Linkwitz has made this very point often, and I totally agree with him.

There might be an issue here with pop and rock which is recorded really screwed up. So they isolate performers in padded boxes and then add reverb and lots of ridiculous effects. So I suspect when that mess is played back then it is a regular free for all.

The klipsch R-15ms I'm using measure +-3dB from 50hz-14khz 1m as far as to 90° off axis, so that isn't the issue. My room is too live, and it screws up the imaging, not necessarily frequency response, which is +-5dB at the MLP from 23hz-16khz. Its well established that small room acoustics are generally harmful to accurate sound reproduction. My bedroom, for example, is 12'x11', hardwood floors, bare walls etc. The reverberation is so bad in there that it's hard to localize pinpoint sounds even coming from the center channel. Its generally agreed a mix of absorption and diffusion is best if one wishes to preserve some liveliness.

Honestly though, if a recording doesn't have reverb, I don't want to add unpredictable reverb from room acoustics, something like Audyssey DSX, which simulates ideal first reflections is ideal.

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[speakerman39]

Yeah I got some serious audiophool vibes from that site. Remember, George Cardas makes super expensive snake oil cables. The other issue I have with the site is the guy immediately starts suggesting placement along the side walls so you can spread the speakers farther apart. Anybody who had a basic grasp on acoustics will tell you side wall placement is the worst option for multiple reasons. Secondly the author never stated exactly how much channel separation you needs and why this necessitates side wall placement. Its generally recognized the front left and right speakers should form an equilateral triangle, +- 8°. Unless one has placed their home theater in a walk in closet, most front walls are wide enough to accommodate this.

There are simple established rules for speaker/listening position placement, such as the 38% rule, equilateral triangle, etc., all have a mathematical basis. No voodoo required.

I've already done the measuring, I don't have any low frequency problems, I'm +-5dB from 23hz-200hz, the main issue I have is poor imaging from reflections, the left side of my system sound much more prominent than the right side. Adjusting trim settings doesn't help, because its a frequency problem with the left side of the room accenting the high end. Its the worst among the front L/R speakers. Measuring the frequency response of the front L/R speakers gives me a -+6dB response from 23-16khz at 1/3 octave smoothing. My room has hardwood floors and bare walls. I have a large window on the right side of the room that I haven't decided how to treat yet. Not a fan of blackout sound reducing curtains, may attach some panels to a board and make a removable treatment that I can hang in front if the window.

I will try to take some pictures and measurements and post back here.



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Yeah the article starts of good, but then kind of takes a dive. My hope was that you could get some useful info out of it. My guess is that the author somehow got distracted when writing the article. Then, he went back later to finish and lost his focus to some extent. There is a bit of useful info. The rest not so much. Forgot to mention that to you when I posted it. My apologies! It sounds like you picked up on it anyways.


Cheers,

Phil

 

[yepimonfire]

I know you've mentioned your dislike of room correction, but you might find Audyssey to be helpful in your room. Also, imo the equilateral triangle is overstated and should you end up there, it should be by experimentation. This is especially true if you add a center.

Audyssey can't fix imaging problems due to sound bouncing off the walls, only frequency response or phase issues (for example, 45-55hz being out of phase at the MLP due to resonances from the rear wall). I've put some of the panels up for the left, right and center early reflections and already I can hear better localization across the front sound stage.

Even if I wanted to try audyssey I'm stuck with onkyos useless accueq, which can't even get the levels right let alone eq.

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[yepimonfire]

Most rooms do not need treatment. Reflections are a good thing and give the sound depth. There has been too much nonsense about killing reflections in the home environment. If truth be told most domestic spaces do not have enough reflections.

Again the problem is the all too common lousy speaker issue. Reflections are a problem for speakers whose off axis response does not mirror the axis response sufficiently. This is a common speaker defect. When this occurs then reflections are a problem. The problem though in that case is the speaker and not the reflections. Good speakers still sound very good in highly ambient spaces. Saul Linkwitz has made this very point often, and I totally agree with him.

There might be an issue here with pop and rock which is recorded really screwed up. So they isolate performers in padded boxes and then add reverb and lots of ridiculous effects. So I suspect when that mess is played back then it is a regular free for all.

I also would like to add, IMO, you're too quick to discredit the effect of the room on audio problems, while it is true poor off axis response lends to worse in room response due to reflections, the negative effect of reflections on imaging cannot be solved with better speakers, and while a high q sub/speaker will exacerbate inaccuracies in the bass due to room modes, any musician, including myself, will tell you room modes screw up response even from acoustic instruments.

Its also worth noting that walls do not reflect sound with a flat frequency response, some frequencies are absorbed, some amplified, even if you had magical speakers that had +-0dB and 360° off axis response you would still have innacurracies caused by room reflections.

I've listened to both music and movies in a dead room before, and I much prefer it to a messy unpredictable reverberating room.

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[gene]

Here is an article that you may find useful. I found it to be very informative. One of these days down the road I plan to do some treatments as well. Just not near that stage yet. Anyways here is the article:

http://www.barrydiamentaudio.com/monitoring.htm


Cheers,

Phil

Remember too that cables are directional. Sometimes this is because the connections differ at each end (some designs leave "ground" unconnected at one end to minimize noise transfer). Even if the connections are the same at both ends, all cables will become directional once they've been used long enough to break-in. Some manufacturers put arrows on the cable or on the connectors to help with proper orientation. When I start using a cable without arrows, I orient it so any writing on the jacket follows the direction of signal flow.

It's hard to take anything on that page seriously when stuff like this can be found there.