[Nyal Mellor]

Jim - last night I was at a clients house where they had set up their speakers and listening position according to the method used by Vandersteen, which is a similar mathematical approach. The speakers were 6ft out into the room.

Funnily enough when I measured it with a high resolution real time analyzer using pink noise what I found was a 10db bump at the listening position at 62hz. This was the 2nd length mode. When we played a 62Hz sine wave to find the nulls we found a nice null about 1.5ft in front of where the Vandersteen method put the listening seat. My guess is the reason for the difference was that the back wall was mostly glass, hence the peaks and nulls of the 2nd length mode weren't distributed as per theory.

So, like as I said, these mathematical models will get you in the ballpark, and they are a massive improvement from just plonking stuff down where it looks good. To get the last 20% though you absolutely have to measure in room.

[bmckenney]

Jim - last night I was at a clients house where they had set up their speakers and listening position according to the method used by Vandersteen, which is a similar mathematical approach. The speakers were 6ft out into the room.

Funnily enough when I measured it with a high resolution real time analyzer using pink noise what I found was a 10db bump at the listening position at 62hz. This was the 2nd length mode. When we played a 62Hz sine wave to find the nulls we found a nice null about 1.5ft in front of where the Vandersteen method put the listening seat. My guess is the reason for the difference was that the back wall was mostly glass, hence the peaks and nulls of the 2nd length mode weren't distributed as per theory.

So, like as I said, these mathematical models will get you in the ballpark, and they are a massive improvement from just plonking stuff down where it looks good. To get the last 20% though you absolutely have to measure in room.

I checked our your website and followed the link to HAA.  Can you give me a rough idea how much a consultation costs?  I'm not near you, but am interested in knowing the cost none the less.

Thanks,
Bryan

[jimdgoulding]

Jim - last night I was at a clients house where they had set up their speakers and listening position according to the method used by Vandersteen, which is a similar mathematical approach. The speakers were 6ft out into the room.

Funnily enough when I measured it with a high resolution real time analyzer using pink noise what I found was a 10db bump at the listening position at 62hz. This was the 2nd length mode. When we played a 62Hz sine wave to find the nulls we found a nice null about 1.5ft in front of where the Vandersteen method put the listening seat. My guess is the reason for the difference was that the back wall was mostly glass, hence the peaks and nulls of the 2nd length mode weren't distributed as per theory.

So, like as I said, these mathematical models will get you in the ballpark, and they are a massive improvement from just plonking stuff down where it looks good. To get the last 20% though you absolutely have to measure in room.

Damn!  10db is quite a bump.  When I changed my set up I got rid of an audible bump somewhere around there or so it sounds.  Sounds more even now.  Nice work.  Think I'll queue my group down here in Houston to this discussion.  Thanks.

[stvnharr]

I know Master Set Steve hasn't done any, but has anyone else taken room measurements to confirm their speaker placement?

I've been thinking about this very question, which in the past of which I have been rather dismissive.  However, I tend to think that frequency measurements after a Master Set should be quite revealing. If MS, is done close to perfection, you do get equal sound pressure and frequency distribution in most all of the listening room.  This should be easy to show with 3 sets of measurements, one in a centered listening postion and 2 others in front of each speaker at same distance in the room.  There shouldn't be much variance.
I don't have the means to do this.  Kind of wish I did, as it could be quite useful I think.
I think it would also be interesting to compare the above with same measurements on a Cardas, or any other setup.

Steve

[TooManyToys]

Wow, what a great idea.   




 

[jhm731]

I know Master Set Steve hasn't done any, but has anyone else taken room measurements to confirm their speaker placement?

I've been thinking about this very question, which in the past of which I have been rather dismissive.  However, I tend to think that frequency measurements after a Master Set should be quite revealing. If MS, is done close to perfection, you do get equal sound pressure and frequency distribution in most all of the listening room.  This should be easy to show with 3 sets of measurements, one in a centered listening postion and 2 others in front of each speaker at same distance in the room.  There shouldn't be much variance.
I don't have the means to do this.  Kind of wish I did, as it could be quite useful I think.
I think it would also be interesting to compare the above with same measurements on a Cardas, or any other setup.

Steve

Great!

Buy or borrow a Radio Shack Meter and take some measurements.

Here's test tones and meter corrections:

http://alanmaherdesigns.com/DIY.aspx

http://www.subwoofer-builder.com/SPL-corrections.htm

[TooManyToys]

An RS setup is not going to do it.

IMO, it most likely would require at least the ability to record and display decay.  If the positioning of the speaker is dependent on the clarity and evenness of a guitar note, I would suspect the classic measurement for "ringing" would be the best choice.  That is why I mentioned REW posts ago.

The locating procedure is utilizing the frequency of the bass in the aforementioned song as it criteria, locating the speaker where there is neither reinforcement, cancellation or time blurring.  It may not be so kind to to other frequencies however, but that's OK.  I'm sure a lot of work went into finding the best "tool" to use.

In the end, Steve's original assertion may be correct, that with moderate common equipment it may not be possible to document or show the improvement.  But it may.

[jhm731]

An RS setup is not going to do it.

IMO, it most likely would require at least the ability to record and display decay.  If the positioning of the speaker is dependent on the clarity and evenness of a guitar note, I would suspect the classic measurement for "ringing" would be the best choice.  That is why I mentioned REW posts ago.

The locating procedure is utilizing the frequency of the bass in the aforementioned song as it criteria, locating the speaker where there is neither reinforcement, cancellation or time blurring.  It may not be so kind to to other frequencies however, but that's OK.  I'm sure a lot of work went into finding the best "tool" to use.

In the end, Steve's original assertion may be correct, that with moderate common equipment it may not be possible to document or show the improvement.  But it may.

The RS will allow Steve to confirm his MS speaker position's bass response and compare it to a Cardas location.

If he wants a more detailed analysis, yes, he'll need a better measurement system.

I use a TacT RCS and a calibrated Linear X mic, and can compared seven different measurements. I use this to fine tune my speaker and listening positions.

Have you done any in-room measurements?

[TooManyToys]

Yes I have.  Not with my current setup but I just haven't had the time and now only have access to REW.

Until my old company closed our facility last year, I managed an R&D lab where we did NVH work.  I had also used some of that equipment years ago to document a room.  It was much more sophisticated then REW and the consumer instruments, but each of the test gear kits we had ran $100k.  I also use to bring home a Rion SA77 instead of an RS meter, so I guess I'm a little spoiled.  I just don't think an RS meter is consistent nor calibrated enough to make a reasonable judgment of what's being asked.

So to answer the implication, yes I have some experience with sound equipment.

[stvnharr]

The RS will allow Steve to confirm his MS speaker position's bass response and compare it to a Cardas location.

If he wants a more detailed analysis, yes, he'll need a better measurement system.

I use a TacT RCS and a calibrated Linear X mic, and can compared seven different measurements. I use this fine tune my speaker and listening positions.

Have you done any in-room measurements?

I think we are talking apples and oranges here.
For one thing, I am not going to do a Cardas set. I've done them, and at best, you get one small listening spot with diffuse imaging, and you can only sit in that one spot for listening. It's also not appro in my present listening room as I don't sit in the middle of the room.

I was thinking more about doing a frequency sweep at the 3 positions I mentioned with speakers in each set up, and comparing graphs of the results.  I have no equipment or inclination to do this. But I do think this could be useful for comparison purposes.

However, failing that, all one has to do with a Cardas set is play a disc similar to the MS setup disc, one with a perfectly centered voice line, and move in front of each speaker as it plays and listen to what happens to the voice. Then listen to the same on a perfectly done MS, and listen to what happens to the voice.
The idea behind MS is to make the two speakers as one single sound source, rather than two sound sources just summing together at slightly differing times.

As to bass response, with MS you move the first speaker to find the smoothest bass. The bass line on the setup disc may not have every single possible sub 150hz note, but it's a reasonable sample and easy to hear.  Every room and every speaker does this bass line a bit differently, and you position accordingly. I do think that one could also do this with a proper equipment, although test tones are not quite the same as a vibrating string.

For me, the magic in MS is the balanced sound throughout the room, not the bass.
Also, with MS I can properly listen to string quartets, which out in the room sets like Cardas utterly destroy. Unlike most folks, I mostly listen to classical.

[jimdgoulding]

"You know if Master Set Steve hasn't done any, but has anyone else taken room measurements to confirm their speaker placement?"

Seems to me, this is germane to any advance in a real world experience to include where a listener sits in a particular room.  Type of speakers and their frequency range, too.

[jimdgoulding]

Jim - last night I was at a clients house where they had set up their speakers and listening position according to the method used by Vandersteen, which is a similar mathematical approach. The speakers were 6ft out into the room.

Funnily enough when I measured it with a high resolution real time analyzer using pink noise what I found was a 10db bump at the listening position at 62hz. This was the 2nd length mode. When we played a 62Hz sine wave to find the nulls we found a nice null about 1.5ft in front of where the Vandersteen method put the listening seat. My guess is the reason for the difference was that the back wall was mostly glass, hence the peaks and nulls of the 2nd length mode weren't distributed as per theory.

So, like as I said, these mathematical models will get you in the ballpark, and they are a massive improvement from just plonking stuff down where it looks good. To get the last 20% though you absolutely have to measure in room.

Nyal-  Hi.  Noted in your study is that a better result was achieved by moving the listening seat.  I hope all we listeners have the option to experiment with this.  It's of equal importance to the total gestalt of our efforts, IMO.

[TooManyToys]

Steve,

I spent about two hours yesterday going through the procedure you've posted, well the best one can do when you're doing it for the first time.

I was able to discern the right speaker domination as I brought the speaker out and then got clearer notes at around 34" from the rear.  It was 1/4"ed out to about 36" at the point as I think I improved the clarity of the note a little more.  But that's a tough call between those two measurements.

The left side was then "worked" and it's out about 34".   I realize it's not about the distance, but I'm adding that just as a reference.  I can't say I found the magic spot as yet.  I have the sound back to about center stage, it is improved in clarity, but I can move the left around a bit without really finding an improvement.  Of course, maybe I don't know what I'm looking for  .

Those distances are much more palatable in this family room then the Cardas distance at 61.6" from the back wall.

I was going to give it another try today but my left ear is ringing loudly again so I've to wait until this tinnitus calms down again.  I went down to the farm yesterday afternoon and it was time to run the dozer around to keep it limber, but I should have waited a few days and kept the ears good.  Tomorrow and Sunday are Christmas tree cutting days so the chainsaw isn't going to help either.

[stvnharr]

Steve,

I spent about two hours yesterday going through the procedure you've posted, well the best one can do when you're doing it for the first time.

I was able to discern the right speaker domination as I brought the speaker out and then got clearer notes at around 34" from the rear.  It was 1/4"ed out to about 36" at the point as I think I improved the clarity of the note a little more.  But that's a tough call between those two measurements.

The left side was then "worked" and it's out about 34".   I realize it's not about the distance, but I'm adding that just as a reference.  I can't say I found the magic spot as yet.  I have the sound back to about center stage, it is improved in clarity, but I can move the left around a bit without really finding an improvement.  Of course, maybe I don't know what I'm looking for  .

Those distances are much more palatable in this family room then the Cardas distance at 61.6" from the back wall.

I was going to give it another try today but my left ear is ringing loudly again so I've to wait until this tinnitus calms down again.  I went down to the farm yesterday afternoon and it was time to run the dozer around to keep it limber, but I should have waited a few days and kept the ears good.  Tomorrow and Sunday are Christmas tree cutting days so the chainsaw isn't going to help either.

Dear TMT,
Well MS at the first go can be quite a task as it's all uncharted territory and a new learning experience.
I find that the biggest thing is to just listen to the bass line of the song to get referenced to what the line does in your room with the speaker. I usually use the first verse for this and just silently count the notes as they are playing, noting which notes sound louder or have some kind of accentuation to them.
It's pretty easy to find where all the music seems to come from the one speaker as it is moved out from the wall.
I noted that you were out 34" from the wall.  That seems quite far out. Once you get to the one speaker dominant position there should only be a zone of maybe a foot where the speaker maintains this, and beyond that the sound moves back to centered.

Matching with the second speaker can be very tricky, if you are not able to find a real definable bass smoothing point. I find that when this occurs that I just try to even out the sound by sitting in front of each speaker as well as in a centered position. When you are in a matching zone, the voice line will stay centered from each position.

Also, when doing the fine movements keep them small, like to no more than 1/8th inch. I use a tape measure for this as it's real easy to make the movements much too large.

Allow a lot of time for doing all this MS stuff.  A couple hours can pass by fairly quickly. And if you go tone deaf, which can happen, you have to just quit.
Remember, you are doing this from virtually no reference of where you are going and what cues to listen for and really what to do. If you can get a balanced sound from the 3 positions, you are about 98-99% of Master Set, and this should lead to a lot of relaxed listening.
DIY MS is a lot of trial and error. My instructions are a beginning. It's not at all like doing a Cardas set, which goes rather quickly.

Steve

[TooManyToys]

.........I noted that you were out 34" from the wall.  That seems quite far out. Once you get to the one speaker dominant position there should only be a zone of maybe a foot where the speaker maintains this, and beyond that the sound moves back to centered.

I'll be repeating this process a few times to confirm how it goes.  I didn't think 34" was that far out of non Master Set placement.  But if I overshoot the ideal and it's closer, I would expect that there would be more bass reinforcement closer to the wall.

Matching with the second speaker can be very tricky, if you are not able to find a real definable bass smoothing point. I find that when this occurs that I just try to even out the sound by sitting in front of each speaker as well as in a centered position. When you are in a matching zone, the voice line will stay centered from each position.

Also, when doing the fine movements keep them small, like to no more than 1/8th inch. I use a tape measure for this as it's real easy to make the movements much too large.

Allow a lot of time for doing all this MS stuff.  A couple hours can pass by fairly quickly. And if you go tone deaf, which can happen, you have to just quit.

Remember, you are doing this from virtually no reference of where you are going and what cues to listen for and really what to do. If you can get a balanced sound from the 3 positions, you are about 98-99% of Master Set, and this should lead to a lot of relaxed listening.
 
DIY MS is a lot of trial and error. My instructions are a beginning. It's not at all like doing a Cardas set, which goes rather quickly.

Steve

I placed blue painters tape on the floor for reference with special markings at my interpretations of "sweet spots".

Thanks for the comments.

Just thought of another question.  All of the instructions appear to be rear wall related, but what about side wall considerations?

[jhm731]

Jack-

Based on my MS trials and measurements, I agree with Steve, that 34" from the wall seems too far out based on your posted room set up.  I'd try it again with the center of the woofers 27" from the back wall, and 38" from the side walls.

How high off the floor are the centers of the woofers?

[stvnharr]

I'll be repeating this process a few times to confirm how it goes.  I didn't think 34" was that far out of non Master Set placement.  But if I overshoot the ideal and it's closer, I would expect that there would be more bass reinforcement closer to the wall.

I placed blue painters tape on the floor for reference with special markings at my interpretations of "sweet spots".

Thanks for the comments.

Just thought of another question.  All of the instructions appear to be rear wall related, but what about side wall considerations?
[/quote]

Dear TMT,
Remember, you should be setting up along the long wall of the room. You should have the speakers at least 3 feet away from any side wall.  With the toe in that comes the final setup, this should mitigate any sidewall reflection issues.
Most folks, including myself in the pre MS days, tend to set up speakers on short wall of room and sit a fair ways away.  There are always sidewall reflection issues with this.

Not sure all of what you may have read about what I have written, but if you can apply the binoculars focusing analogy to what you are doing with the speakers, it will help.
Hopefully you have a wide enough room for some flexibility with spacing between the speakers. Getting the speakers far enough apart but still keeping a solid center image will help.  I think this makes it easier to hear things during the setup as there is less sound overlap between the two speakers.  Be sure to take some time to play with this.  It's like the first step with binoculars in adjusting them to the width of your eyes.  You are adjusting the speakers to the width of your room.
As to measurements, measurements I have given are rough measurements from wall behind the speaker to the middle rear of the speaker enclosure. Distance from wall behind the speaker to speaker baffle are entirely dependent on depth of the cabinet.  While the sound does originate at the speaker baffle, it's just easier to approximate the distances given as from wall to rear of the speaker enclosure as that is the shortest relative measurement.  It is also an irrelevant measurement and meaningless in the overall picture.
What is important is the "zone" where all the sound comes from the one speaker moved out from the wall. This is where you can set the "anchor" speaker and not have it affected by the other speaker.
As to bass, because MS is relatively close to the wall behind the speakers, there is more room gain and bass reinforcement than when the speakers are 5 feet out into the room. But that's not the reason for doing things in the MS way.  It's about the "zone" in the previous sentence.

Using the tape on the floor is a good way to mark the good spots, and is very helpful. When you are looking for the smoothest bass, just be sure to make small movements, 1/16th is pretty small and can get real tedious and I think 1/8th is about right. A movement of 1/4 inch is too much and you may pass right over the node spots.
Finding a smooth bass spot will help in the matching step, as it can be definitive in hearing the sound from the two speakers lock together.  However, finding the smooth bass spots is not easy as the changes may not be very much.  As such, then it doesn't really matter all that much. But it makes matching the 2 speakers more difficult, and you have to do as I often do and go for the balanced, and same, sound from the 3 listening positions, as that is a hallmark of Master Set.

While MS can be done with any recording that has a definitive bass line and a solidly centered voice, the Rob Wasserman DUETS recording with Jennifer Warnes, Ballad of a Runaway Horse, works the very best.  Both the bass and the voice are easy to hear and there is nothing else to clutter up the sound and confuse the ears.

Hope this helps, and good luck with DIY Master Set.
Feel free to ask any questions as they occur, and I will do my best to answer them to the best of my ability.

Steve

[Nyal Mellor]

Steve

I don't understand why movements of 1/4" could affect 'nodes'. To really affect bass response you are talking more like feet than inches. Its simple physics.

Nyal

[TooManyToys]

Jack-

Based on my MS trials and measurements, I agree with Steve, that 34" from the wall seems too far out based on your posted room set up.  I'd try it again with the center of the woofers 27" from the back wall, and 38" from the side walls.

How high off the floor are the centers of the woofers?

23" and 31" for the woofers.  38" in from the side walls might have conflicting space with the TV if they are only 27" from the back wall.  I'll move the JC-1's and see where things are when I play again.

Remember, you should be setting up along the long wall of the room. You should have the speakers at least 3 feet away from any side wall.

Most folks, including myself in the pre MS days, tend to set up speakers on short wall of room and sit a fair ways away.  There are always sidewall reflection issues with this.

As noted earlier in this thread, this is a family room and there is no way this setup is going along the long wall, so it's going to be what it is.  It is also not a large house; so again, it will be what it is.

Understood all the rest from going over past threads / posts.  I use Google extensively.

..  the Rob Wasserman DUETS recording with Jennifer Warnes, Ballad of a Runaway Horse, works the very best.  Both the bass and the voice are easy to hear and there is nothing else to clutter up the sound and confuse the ears.

Feel free to ask any questions as they occur, and I will do my best to answer them to the best of my ability.

Steve

That is the song I'm using.

Steve

I don't understand why movements of 1/4" could affect 'nodes'. To really affect bass response you are talking more like feet than inches. Its simple physics.

Nyal

I'm with you on that.  So far I'm just going along for the ride.

I'll reattach my room diagram, this time showing:  4" grid lines, the current MS speaker position, and the Cardas set points.  I'll also attach two images to show the lack of room for movement.  The JC-1s can get moved, but the positioning between the display and the speakers may have conflicts to width as well as visual clearance.







Thanks guys for the help.

[stvnharr]

Jack,
From looking at your room pictures, I don't think Master Set will work in your room. I don't think you can get the speakers to equally match into one, which is what MS is about. Short wall setups are too prone to reflective issues, too much center overlap of sound, and large screen video equipment is a huge reflective surface. Or it's far beyond my limited expertise in MS.
Just go with what sounds best to you. Every place you put the speakers will sound slightly different, as I'm sure you well know. Just do the best you can, and enjoy.

Steve