As it seems to happen, we have been working on a dedicated home theater for over a year now. It is certainly not the fun part as you wait for other parts of the process get completed. Now I am getting excited as we enter the part where I get to listen to music and watch tv and movies!! At any rate at one point in the process the client was wondering if more side channels would improve the sweet spot for surround sound to all three rows of seating. Dennis Erskine (thanks!) suggested it could work,but we would need to set a different delay for the extra speakers. Since this is a (luckily for me) a no holds barred to get the best results project, we purchased a processor Dennis recommended.It is a Symnet Express 8by8 processor. It is way over the top for professional product what is being done here as it has many more features than we are taking advantage of. We did manage to figure out the software and make some adjustments.I am looking for some input on the way we accomplished this and make any appropriate recommendations?
We have three pair of identical side channels one pair aligned approximately(and above) with each row of speakers. We fed the right and left side output of the Lexicon MC 12 to two of the inputs of Symnet and then each pair of side speakers was feed a set of outputs. Since the distance from the front speaker to the side speaker is what is being adjusted for (?) I used the closest pair to the front as a no delay(the lexicon will set it's delay) and then added delay for the distance further back in the room (example 7 feet from one pair to the next).The Symnet figures the delay in the software for the measured distance,but it is around 1 millisecond per ft. The third pair was about the same distance from the second so double the amount of delay was added for the third row. When we do the planned automated set up with the supplied microphones from Lexicon we are going to use only the closest set(not delayed by the Symnet) of side speakers. It seems a little weird as I would prefer the mics to be more towards the middle of the room to get a good average for the equalization etc. The active speakers for the Lexicon automated setup will be forward of the mics.After we complete the eq then we will have to adjust the side levels somewhat to compensate for the output from the extra speakers. Hey I appreciate any input! Hopefully some insight will be gained from this for anyone interested in multiple sides. I will keep the forum informed on the results as we go along. Thanks Dallas

OOPS! I meant appoximately aligned with each row of "seating" not speakers. Thanks again

Ok, first, that's one giant paragraph. In the future...

In any case, a couple things seem strange actually. I'm not sure exactly why you'd need to delay extra surround speakers, this is usually not done in most cinemas, it's just a big array. If you have multiple rows, it's fairly normal to just have arrays to the side and not have delays for the various speakers. However, I do see the thinking behind it if you are trying to align things best for a main listening position, however this seems like a slightly crude way to do it, because you're not going to get them all in phase. However, it isn't particularly a big deal IMO. I'm kind of surprised Dennis recommended adding in additional delay complications for side arrays. Never heard this done before.

The way I read the paragraph, you are NOT delaying the main surround speakers(not main as in 'dominant' but the ones nearest to the main listening position, presumably in the first row), and then for rows farther back you are adding a delay? This is backwards, you'd have no delay on the ones furthest away, and additional delay to the speakers nearest the main listening position.

Perhaps I'm reading that wrong, but that seemed backwards.

Dallas,

First things first: you need to pick a sweet spot from which to calibrate distances and levels. The speakers can't be the same distance from multiple seats, so pick one spot and stick to it. Don't use the automatic calibration routine in the Lexicon for setting distances; use a tape measure instead.

Write down the distances from the chosen sweet spot to all 11 speakers (3 pairs of side speakers). Enter the distance for all the speakers in the Lexicon. For the sides, pick the ones that are furthest from the sweet spot.

Run the side speaker outputs from the Lex to the Symnet. Run three pairs of outputs from the Symnet to their respective amps, and then to their respective side speakers. For the side speakers that are furthest from the sweet spot, dial in a delay of zero in the Symnet. For the other two pairs of side speakers, dial in the difference in distance between them and the furthest pair. So if furthest side speakers are 12 feet away, and the other pairs are 10 and 8 feet away from the sweet spot, then you'll be using the Symnet to delay them by 2 and 4 feet respectively (or whatever those distances work out to in milliseconds).

Now all your side speakers sound like they are 12 feet away. The one that is actually 12 feet away (the furthest from the sweet spot) didn't need any additional delay from the Symnet. Make sense?

The Lexicon lets you run auto distance, level and EQ all together or individually. You can either run the levels automatically or do it manually with a SPL meter. If you do it automatically, it will set levels for a spot exactly in the middle of all 4 mics. Personally, I would put a SPL meter at the sweet spot and calibrate levels manually. Whichever method you use, the three side speakers on each side will be calibrated as a single channel. If you were to calibrate the side speakers individually, then each side channel would be three times as loud compared to the other channels.

Remember to set crossovers before doing the auto-EQ. The EQ system shouldn't have a problem with multiple speakers for each channel. It seems to handle dipole speakers fine, so diffuse sound doesn't trip it up. Besides, it's actually listening to the room, not the speakers, to find out which bass frequencies linger for the most time and take the longest to decay. Keep in mind that it only works for frequencies below 250Hz, and is limited to addressing long decay times. To smoothen out low frequency repsonse, you'll need to use physical treatements (bass traps, etc) because the Lexicon doesn't really address this problem. Same for frequencies above 250Hz; passive treatments.

Good Luck,
Sanjay

Thanks! Ok I am understanding things a little better now. You want the output of the three pair of side speakers to sound like one giant "side" from the sweet spot?
Actually the sweet spot is more or less in the middle of the room so the "front" and the "rear" sides are about the same distance from the sweet spot. Although I will measure each distance critically. The biggest compensation will be on the closest "middle" side speakers?
Sorry about the run on paragraphs! Will try to avoid on future posts.

You want the output of the three pair of side speakers to sound like one giant "side" from the sweet spot?Exactly! Since your front, centre and rear speakers will all be time aligned to that one sweet spot, it makes sense that all the side speakers should also be time-synched for this spot. The biggest compensation will be on the closest "middle" side speakers?Correct. Measuring from the sweet spot, the closest pair of side speakers will need the most additional delay from the Symnet. The next nearest pair will need less additional delay. The furthest pair will need no delay from the Symnet. Your goal is to make all three pairs of side speaker appear the same distance away.

Sanjay

Sanjay, excellent as always! :)

Sanjay is da bomb!

Thanx Chris, thanx Scott. Your cheques are in the mail.

Sanjay

Man, I get PAID for letting you do all the 'splainin? What a life! :D

I am working on completing a fabric and acoustic system for the room. As soon as we complete that I am going to tweak the audio. I should be able to comment on the side channel results later this week. Thanks again Dallas

***IN between jobs today, saw that email*** You guys are a riot.

Things are moving along as before; somewhat slowly.
I did set up the three side speakers with the Symnet, now all three are arriving at the sweet spot at the same time.
I did a quick level adjustment using Goldlines 5.1 test disc and the internally generated test tone with my Audiocontrol analyzer. About the same results for both. The sound is pretty darn fantastic, however I do note that the closest side speakers to the sweet spot seem louder? I suspect it would make sense to lower the level of the close side speaker and increase the others as required. The sweet spot should hear all the sides at the same level. Correct? Things are looking up for this arrangement though. Phil Collin's Live DVD sounded like I was at the concert! It is a great demo.The first song is a drum solo with three drummers.WOW!

Dallas, I suspect it would make sense to lower the level of the close side speaker and increase the others as required. The sweet spot should hear all the sides at the same level. Correct?Correct. And I completely forgot about this in my previous posts. Each pair of side speakers should be equally loud at the sweet spot. This should be done using either the Symnet or the amps (if they have volume level control).

With proper time alignment and levels dialed in, the three speakers on each side should be heard like they're one giant side speaker (to use your words). Only after you've done that should you do the normal calibration on the Lexicon; otherwise the levels for the sides will come out wrong. The first song is a drum solo with three drummers. WOW!That works out to one drummer for each pair of side speakers. Wow indeed.

Keep the updates coming. I'm curious to find out how the set-up ends up sounding, especially after running room EQ.

Sanjay

Thanks Sanjay!We are just about completed with the fabric installation. It is a lot of work!
Once that is completed we can install the chairs.I have found that big chairs are good bass traps. Then we can finally do some Eq and other tweaking.Probably Tuesday or Wednesday? I will try to post some pictures along with additional comments about the results.

Dallas, Then we can finally do some Eq and other tweaking.Just to clarify, I was talking about the room EQ feature built into the Lexicon. Curious how much difference it will make in your set-up. You can toggle it On/Off on-the-fly for quick comparisons. Probably Tuesday or Wednesday? I will try to post some pictures along with additional comments about the results.Pics would be nice. But no rush; post when you can.

Sanjay

I am counting on the automated eq in the Lexicon to make a nice difference! Currently the room seems to have some typical mode issues that I hope the eq can flatten out at the sweet spot. I will update this thread as I get the results.Thanks again for the great input. Dallas

Still chugging along. The customer is watching and listening to his new set up,but not at all fine tuned yet. We put in a couple of the chairs so he can mess around with it anyway.
There are some additional curtains and drapes that are not completed as yet. I am going to wait unitl they are installed before calibrating anything. Looks like late next week or early in the following. I would have never guessed we would be into April on this project,but such is the world of "custom installation"
I have never added a picture to a post so bear with me if there is a problem,but I attached a couple of pictures of the current status. Here goes.Dallas

How about that it worked! The one picture is Dan our installer putting GOM over the right side speakers. They are recessed of sorts into a soffit. We also made the remaining soffit (on both sides) into a bass trap. The other pic is from behind. The screen is mostly covering the front speakers. Two LG LCD panels on either side for keeping track of multiple events. It is starting to feel like a theater anyway.
The windows had to be there! Oh well. It will be dark.

Today I set up the automated eq, and level set. I manually set the distances. Using the Symnet I set the levels on the three side speakers(per side) to be the same at the main chair.The proper delays were already in place from our last trip I have never used the Lexicon eq,but it was simple and worked very well. I noticed an improvement in bass right away,but if you turn it on and off while listening you can tell it actually improves the midrange presentation also.
After experimenting I found the "High" setting proved to be the best compromise. I found I also preferred the loudness "off".
I am going to reequalize a few more times with the mics in different positions to see what works best.
The side channels basically sound like one big side channel as discussed. This system is really starting to sound good.
We are using two front subwoofers and a separate LFE woofer in the rear.I have not spent that much time researching,but am I missing anything by not having the rear woofer functional during music playback?
I will continue to update as I fine tune things. This system really deserves to be super tweaked. Thanks Dallas

Dallas, I have never used the Lexicon eq, but it was simple and worked very well.One of the best things about it is the simplicity of use. If you've ever tried to do any measuring and EQing manually, you'll really appreciate the 'push the button and walk away' nature of the Lex EQ. I noticed an improvement in bass right away, but if you turn it on and off while listening you can tell it actually improves the midrange presentation also.Yeah, the first thing I noticed is how much clearer dialogue was. Keep in mind that it's not EQing anything above 250Hz. However, by addressing low frequencies with long decay times, details that were previously obscured (irrespective of frequency) are now more easily heard. Whether you're using passive treatments or electronic correction, dealing with low frequency problems (especially ringing) can improve the sound over the entire frequency range. After experimenting I found the "High" setting proved to be the best compromise.I go back and forth between High and Max, using High more often than not. I found I also preferred the loudness "off".Because the EQ system reduces some of the boominess, there can be a subjective impression of the bass suddenly sounding thin. To compensate, Lexicon built in a mild bass boost into the EQ system.

The Loudness contour is a separate feature, and is mostly useful when listening at lower volumes. As the volume gets lower, our human hearing perceives the bass as getting softer than other frequencies. The Loudness contour uses Fletcher-Munson curves to gently boost lower frequencies proportionately. This way, as you lower the volume, all the frequencies 'sound' like they are being lowered equally. The side channels basically sound like one big side channel as discussed. This system is really starting to sound good.Great to hear that. I'm glad you're getting the intended result from the side speakers and the Symnet. I have not spent that much time researching, but am I missing anything by not having the rear woofer functional during music playback?The rear subwoofer will be functional during music, as long as the music has a discrete .1 channel.

The MC-12 treats derived bass (filtered from any channel set to Small) and discrete bass (found in the .1/LFE channel in the source) as individual entities.

All the filtered bass from the main channels will come through the two subs (in stereo). The dedicated LFE subwoofer will play only when a .1 channel is present in the source, providing an extra bass kick (as intended).

When the LFE channel is not present, the dedicated LFE subwoofer will be silent and normal bass will be played back through the L/R subs. I will continue to update as I fine tune things. Looking forward to it.

Sanjay

Thanks Sanjay! I am taking a short break from the project. It will be nice however to go back just to experiment with all the audio and video equipment.
I noticed the loudness setting was adding some coloration at levels I would consider pretty loud. As I toggled between on and off. I preferred it off. At least for the cds I was using as test material.
I must be getting old,but I remember discussing the Fletcher- Munson effects back in the early 70s! I am sure that Lexicon if anyone is implementing it properly,but as mentioned I would rather run with out it.
I did a check on levels with my Audio Control RTA and it matched the automated system pretty well except the sides measured a couple of db lower than the rears. LFE came out out 2 db higher than I had measured earlier with the RTA. The Eq bass boost?
I ran out of time,but next trip I am going to try a slightly higher level on the sides. These set ups cannot be treated as a cookie cutter design. Lots of testing required.
Of course this part is kind of fun! Probably head up again next week sometime.
The customer can have a chance to play for awhile.

ddingle ... when using multiple side surrounds, set the level down (in your case) 6dB SPL for each individual speaker. Then with all speakers running, set the level for the combined lot to your reference level.

ddingle ... when using multiple side surrounds, set the level down (in your case) 6dB SPL for each individual speaker. Then with all speakers running, set the level for the combined lot to your reference level.

Thanks Dennis! I want to be clear on this. Using a meter set all speakers to 75db(as an example) except for each of the six sides which you set to 69db? Then treat the 3 speaker per side as one and set the levels to measure 75db when all are on together? I am a little sluggish after our extensive road trip,so I may need some additional explanation :) Dallas

Hi Dallas, I am sure that Lexicon if anyone is implementing it properly, but as mentioned I would rather run with out it.Right. It's not to everyone's preference, which is why it's an optional feature and can be turned off. I find it useful because I tend not to listen to my system very loudly. I did a check on levels with my Audio Control RTA and it matched the automated system pretty well except the sides measured a couple of db lower than the rears. LFE came out out 2 db higher than I had measured earlier with the RTA. The Eq bass boost?You're talking about the automatic calibration by the Lex? Personally, even with V4-EQ installed in my MC-12, I prefer to do levels and distances manually. I only use the EQ portion of the suite.

Sanjay

Hi Dallas, Right. It's not to everyone's preference, which is why it's an optional feature and can be turned off. I find it useful because I tend not to listen to my system very loudly. You're talking about the automatic calibration by the Lex? Personally, even with V4-EQ installed in my MC-12, I prefer to do levels and distances manually. I only use the EQ portion of the suite.

Sanjay
It was pretty close between my measurements and the automatic,but on the next trip I will take the time to manually double check the levels. It is obviously critical to the final result! Thanks

We finally added the window treatments to complete the room. Feeling pretty darn good about the results. Both aesthetic and functional
The side channels are not in your face,but are obviously filling the space. It is at this early stage of evaluating the system, producing what I would describe as transparent surround effects. More like being there.
A testimonial to the great results is the fact that at the end of the day on Thursday the crew and I were just going to catch a few minutes of the rather dreadful movie " Walking Tall" with "The Rock" on Showtime HD. The sound and video were so captivating that we stayed through the entire showing. It was easy to discern the sound effects produced by a Hickory 4by 4 pounding on human flesh. What were they using to simulate that? A watermelon? Explosions had us jumping out of our seats! Nice production quality kept us watching.
I am adding a couple of pictures of the shade system. 2 motorized systems one for the blackout shades and another for the Roman fabric shades. Works well and looks nice also. More to come

The side channels are not in your face, but are obviously filling the space. It is at this early stage of evaluating the system, producing what I would describe as transparent surround effects. More like being there.That sounds ideal. You never want the surrounds to take your attention away from the screen or distract from the front soundstage when listening to music. On properly balanced systems, I usually never notice that the surrounds are even on; that is, until they're turned off and all the sound collapses to the front wall. Sounds like it's coming along just right.

Sanjay

I have been doing some listening and viewing on the system over the last couple of days.It seemed; especially for music that the sides and rears seemed low. I re-measured the speaker levels using my Audio Control analyzer and mike. Using the test generator in the Lexicon,things seemed close to the same all around. I then thought it would be interesting to use the Goldline 5.1 test disc by Tony Grimani. The tests include back channel or EX information along with 5.1 tests. The levels on the sides from the test disc measured lower than the internal generator? Actually the fronts and the woofer measured some what different also. Not sure why? It is a Denon 5910 DVD player. At any rate it gave me an excuse to raise the side channel levels 3 db or so. Now I am getting more of the "wall" of sound we had hoped for. The client commented on positively on it also. I am thinking that the microphone is getting more than your ears do in this situation?Or something. Another factor is the angle of the side channels towards the listening area Depending on your sitting position the level might be higher on one side than the other. It does seem like the right side is more "wall" like.A system of this stature deserves plenty of testing and tweaking. Not finished yet!
I am sending the Audio Control and microphone in for a recalibration. Then I am going to re measure the levels to all six side speakers. I am suspect of my settings on the Symnet device. Going to double check everything. More listening and testing forthcoming.
PS There is a series called "Nothing but trailers" on HDnet that (IMHO) has the best sound and video on the air! Mel Gibson has a new movie called "Apocalypto" coming out. It is about the Mayan civilization. Wow!This feature had such tremendous sonic and visual impact I started laughing! Almost like a ride at the Amusement Park. Quite a demonstration of this systems potential.

The levels on the sides from the test disc measured lower than the internal generator?You may have left some processing on that splits the surround information between side and rear speaker pairs. That could make the sound in each pair a little quieter. Plus, if you have bass managements on, some of the sound may be getting re-routed to other speakers and/or the subwoofers.

When you use the internal test tones, you bypass all the processing, so you get more accurate results. Program material can vary from disc to disc (even test discs). If you calibrate based on the Grimani disc, then your levels may be off when using other test discs.

Finally, where ever the calibrated levels end up, there's no harm in seasoning to taste. If a small boost in the surround levels will make your client happy, then make him happy.

Sanjay

Dallas,

Could you explain what you hope to achieve psycho acoustically with this setup? There's a concept called the precedence effect that is being altered by this. In a no delay setup, you would lock into the the pair of speakers closest to you. In your setup, the front row will here all speakers equally, pulling the side "image" toward the middle speaker. The people in the center will like hear the rears first, the people in the back would be the only ones that hear side speakers as actual side speakers. I'm sorry, I'm too late on this one, but it seems like a gigantic miscalculation of how psycho acoustics work. I can't think of any reason to put in the delays or why you would even want to do so.

Edit - actually, there is *one* possible use for the delay, IMO. If you pick the center row as the "sweetspot" and add 1-2 ms to the middle sides *then* you eq the distances for that row, minimizing audible distortion and enhancing the precedence effect for the front and rear rows, allowing them to pick up more on their own dedicated side speaker. The front row would only hear the front sides, the rear row would only hear the rear sides and the center row would hear all three simultaneously. But if you use the front row as the "sweetspot", you will be creating more problems and solving none.

I then thought it would be interesting to use the Goldline 5.1 test disc by Tony Grimani. The tests include back channel or EX information along with 5.1 tests.

Somehow I missed this thread in its earlier posts. In any case, the Gold-Line 5.1 Audio Toolkit is the test source I have come to trust most. Once you get familiar with it, you have a known set of signals that you are routing through the entire system, from input to output.

Since you have some interesting distance delay issues, I'd like to point out another useful signal on the disk that can be used for subjective adjustment of delays through listening. In the audio test tracks are a series of noise-burst signals originally intended for checking polarity. These signals burst noise repeatedly through pairs of speakers. If you've already checked that the levels are well matched and the polarity is correct, if you hear the location of the noise not spaced properly between the speakers, this is either from incorrect delays or reflections in the room you should treat.

Our hearing is actually more sensitive to time offsets than level. As you would expect, the first arriving source will pull the image in that direction. Most processors these days have you input distances, not delays, so "moving" the image you hear in this test is a little confusing, but not hard to figure out. If you hear the image pulling to one speaker more, that means that from an acoustic standpoint, it's too close or arrives too soon, and the distance in your processor is not set correctly for the effective distance.

When you adjust the distances, entering a shorter distance moves the image away from that speaker. Similarly, entering a longer distance moves the image closer to that speaker. You will have to use one method or the other depending on which other speakers you have already adjusted. It can be a little confusing the first few times you do it, but it works extremely well. Most importantly it gives you a clear method of making judgement calls on final settings where the measurements might tell you two adjacent settings are equally close. You can also listen from an area or multiple seats to evaluate how the settings impact other listeners. I have found very good correlation in getting the images placed properly and more seamless sound field envelopment.

I do this step after settling on the integration and distance settings of the LCR & Subwoofer and after any EQ that will be done to the various channels. More recently I've tested my method a few times and after adjusting the LCR/Sub did the surround distance settings entirely by this test. I then routed signals through the channels to test the actual arrival times, and found my settings to be within the tolerance of the distance settings of the surround processor, where my measurements would have left me guessing + or - . Having checked myself a few times now, I'm confident in the results and I generally have much less to tweak when I do final listening on the system.

Somehow I missed this thread in its earlier posts. In any case, the Gold-Line 5.1 Audio Toolkit is the test source I have come to trust most. Once you get familiar with it, you have a known set of signals that you are routing through the entire system, from input to output.

Since you have some interesting distance delay issues, I'd like to point out another useful signal on the disk that can be used for subjective adjustment of delays through listening. In the audio test tracks are a series of noise-burst signals originally intended for checking polarity. These signals burst noise repeatedly through pairs of speakers. If you've already checked that the levels are well matched and the polarity is correct, if you hear the location of the noise not spaced properly between the speakers, this is either from incorrect delays or reflections in the room you should treat.

Our hearing is actually more sensitive to time offsets than level. As you would expect, the first arriving source will pull the image in that direction. Most processors these days have you input distances, not delays, so "moving" the image you hear in this test is a little confusing, but not hard to figure out. If you hear the image pulling to one speaker more, that means that from an acoustic standpoint, it's too close or arrives too soon, and the distance in your processor is not set correctly for the effective distance.

When you adjust the distances, entering a shorter distance moves the image away from that speaker. Similarly, entering a longer distance moves the image closer to that speaker. You will have to use one method or the other depending on which other speakers you have already adjusted. It can be a little confusing the first few times you do it, but it works extremely well. Most importantly it gives you a clear method of making judgement calls on final settings where the measurements might tell you two adjacent settings are equally close. You can also listen from an area or multiple seats to evaluate how the settings impact other listeners. I have found very good correlation in getting the images placed properly and more seamless sound field envelopment.

I do this step after settling on the integration and distance settings of the LCR & Subwoofer and after any EQ that will be done to the various channels. More recently I've tested my method a few times and after adjusting the LCR/Sub did the surround distance settings entirely by this test. I then routed signals through the channels to test the actual arrival times, and found my settings to be within the tolerance of the distance settings of the surround processor, where my measurements would have left me guessing + or - . Having checked myself a few times now, I'm confident in the results and I generally have much less to tweak when I do final listening on the system.
Wow! Good insight Mark! I must have missed the email notification of this post. I am still fine tuning things on this project although it is sounding way beyond the customers expectations at this point!! Money in the bank as they say. I want to max everything out of course and like everyone else in the forum I enjoy the learning curve
As mentioned we are using the symnet to compensate for the multiple sides. I have noticed the right side being somewhat dominant. I have never used the test patterns you describe on the Goldline disc. I will now. Hopefully I can correct the side issues using them.
Say my disc is getting beat up. It won't play in some discs. Do you know if Goldline will send me another or exchange? Thanks Dallas

Hi Dallas,

Glad someone read and used that info. :rolleyes:

Another tip in the subjective evaluation is that it is very difficult to identify which source arrives sooner on the start of the burst other than where the image places, but we are very sensitive to the decay side of such a burst. Listen for the pull of the burst to one speaker or the other as the burst ends. You can hear the separation of the two arrivals better this way. Obviously if the sound pulls to one speaker on the tail of the burst, that speaker is arriving later. Fortunately this also means the main image will be shifted the opposite direction, so the problem is a little more dramatic to the ear. When they are better matched, the sound will be more stable in the burst and the decay.

This also quickly shows you how various reflections in the room can wreak havoc with image placement. With strong reflections the image may move abruptly with head location or orientation and sometimes even sound akin to a speaker out of polarity. Again, giving some thought to the subjective image location and decay characteristics can be helpful in hunting down the problem.

As I said previously, this has worked extremly well for me and has correlated VERY well with subjective evaluations with real soundtracks. While there are many useful scenes, I like to use the opening thunderstorm & rain in the movie Open Range to evaluate the envelopment and seamlessness of the sound field.

Dallas,

Could you explain what you hope to achieve psycho acoustically with this setup? .


THE SONY strda 9000es has the potentital for 2 side speakers, I was playing with one last week using dynaudio contour sr's. the effect of having two sides added much realism to the presentation (in this case it's one sofa and the duplicate side channels are on an equidistant triangle in front and back of the seating area). THE IMPACT FROM THE PRESENTATION WAS HOLLOPHONIC IN NATURE.

Dallas,

Could you explain what you hope to achieve psycho acoustically with this setup? There's a concept called the precedence effect that is being altered by this. In a no delay setup, you would lock into the the pair of speakers closest to you. In your setup, the front row will here all speakers equally, pulling the side "image" toward the middle speaker. The people in the center will like hear the rears first, the people in the back would be the only ones that hear side speakers as actual side speakers. I'm sorry, I'm too late on this one, but it seems like a gigantic miscalculation of how psycho acoustics work. I can't think of any reason to put in the delays or why you would even want to do so.

Edit - actually, there is *one* possible use for the delay, IMO. If you pick the center row as the "sweetspot" and add 1-2 ms to the middle sides *then* you eq the distances for that row, minimizing audible distortion and enhancing the precedence effect for the front and rear rows, allowing them to pick up more on their own dedicated side speaker. The front row would only hear the front sides, the rear row would only hear the rear sides and the center row would hear all three simultaneously. But if you use the front row as the "sweetspot", you will be creating more problems and solving none.
We actually set up the center row middle seat as the "sweetspot". I measured the distance difference between the front side speakers which is the distance set for the Lexicon and the middle and rear SIDE speakers. The middle is delayed like you say around 1 to 2 milliseconds. Actually middle seat is not exactly correct. The center of the middle row is where the arms of the two chairs on either side are. I am definitely going to experiment with the test patterens Mark Seaton mentioned. Hopefully we can make a darn good sounding system even better. Thanks

Hi Dallas,

Glad someone read and used that info. :rolleyes:

Another tip in the subjective evaluation is that it is very difficult to identify which source arrives sooner on the start of the burst other than where the image places, but we are very sensitive to the decay side of such a burst. Listen for the pull of the burst to one speaker or the other as the burst ends. You can hear the separation of the two arrivals better this way. Obviously if the sound pulls to one speaker on the tail of the burst, that speaker is arriving later. Fortunately this also means the main image will be shifted the opposite direction, so the problem is a little more dramatic to the ear. When they are better matched, the sound will be more stable in the burst and the decay.

This also quickly shows you how various reflections in the room can wreak havoc with image placement. With strong reflections the image may move abruptly with head location or orientation and sometimes even sound akin to a speaker out of polarity. Again, giving some thought to the subjective image location and decay characteristics can be helpful in hunting down the problem.

As I said previously, this has worked extremly well for me and has correlated VERY well with subjective evaluations with real soundtracks. While there are many useful scenes, I like to use the opening thunderstorm & rain in the movie Open Range to evaluate the envelopment and seamlessness of the sound field.

Mark, where are you listening to the speakers? In the Goldline tutorial it indiates you should triangulate with the two speakers being tested. This certainly takes you out of the primary listening area? Of course I have three side speakers with their own processsor for delay. So it may be pretty complicated. Thanks

Mark, where are you listening to the speakers? In the Goldline tutorial it indiates you should triangulate with the two speakers being tested. This certainly takes you out of the primary listening area? Of course I have three side speakers with their own processsor for delay. So it may be pretty complicated. Thanks

I am going to answer my own question? Picking the "money chair" as it were for listening and adjusting the test tones would actually allow you to hear the effects of the delays from that position. Triangulating would not take into account the reflections at the desired seating position? Hopefully I am on track here. I am heading up to the site next week.

Now you're getting it. The whole point is to make subjective refinements and final choices after you know the settings are in the ballpark or have some logical basis.

You want to be sitting forward, facing the center channel as you would be while listening for all of the test cases. You are striving for a well-placed phantom image that doesn't jump around too much when you move your head around. Sometimes this can be difficult, and don't tell me I didn't tell you so if you happen to find some annoying deficiencies. I would suggest playing with this on more than one system, preferrably one you've already set up and know fairly well. Even if things sound good, change the delays for the different surrounds to get a feel for and experience what happens when you make different changes so you know what to listen for and have a better idea of how to fix it.

Remember that in shifting the image with the delays, you can adjust either speaker. Once you get the main speakers set, you then move to the R+RS and L+LS combo where you will want to adjust the sides, since you already set your L&R to behave properly with your center. Generally I work from the center channel rearward.

Everything has been working well on this system. The customer is spending quite a bit of time with it. The Qualia projector has over 1000 hrs on the bulb meter.
On a couple of different occasions I have spent time trying out Mark Seaton's suggested speaker distance technique,using the phase check section of the Goldline disc. It was pretty easy to "see" the image of the "Popping sound" move as we changed the distance settings. With three sides we also experimented with the delays between the sides to what seems like good effect.
Typically it seems like we run out of time,each time we travel to this site (400 miles),so I probably had not set the levels as critically as I would have liked on my previous trip up. Now with the new distance adjustments and newly adjusted level settings, the system is really starting to "disappear". Eric Clapton's Unplugged DVD sounded really lifelike. So did a Madonna concert. Almost like being in the crowd.
This trip I also decided that the bass had some kind of "bump" going on even after using the Lexicon's highly touted auto eq. I hypothesized that the problem was the full range right and left speakers and the subwoofer were interacting in a negative way. I believe the auto eq adjusts the front right and left independently from the right and left front subwoofers? At any rate I crossed the fronts and the subs at 80hz and the "whump" cleared up substantially.
Even though the customer has been pleased with the system from day 1, I like to think of having a reviewer listen to the system while writing an article about it. Would he like the results? At this point the answer is a pretty confident "Yes".
I suppose I could wish the woofers were not built into cabinets? I am sure that is having some negative impact. We did try to isolate them as best we could. Great sound as is however. Thanks for all the help. Dallas

This trip I also decided that the bass had some kind of "bump" going on even after using the Lexicon's highly touted auto eq. ....I believe the auto eq adjusts the front right and left independently from the right and left front subwoofers?The Lex EQ isn't looking to flatten out the frequency response as much as reduce long decay times. If the bump you heard wasn't ringing for a long period, then the Lex EQ probably wouldn't attack it (because doing so could make the sound worse elsewhere). As for individual channels, you are correct: each of the 10 channels are measured and EQ'd independently.

Sanjay

The Lex EQ isn't looking to flatten out the frequency response as much as reduce long decay times. If the bump you heard wasn't ringing for a long period, then the Lex EQ probably wouldn't attack it (because doing so could make the sound worse elsewhere). As for individual channels, you are correct: each of the 10 channels are measured and EQ'd independently.

Sanjay
Thanks Sanjay! It seems to me that the independent measurement is where the problem occurred. The Full range ATCs are directly above the PSB subs. Measuring fine by themselves,when played simultaneously there was some form of "summing" between the ATC and PSB output at some bass frequency producing an aberrant combined response. I hate to lose the bass output of the ATC full range speakers,but the results are noticeably better with the 80hz cutoff.