Speaker positioning and setup.

[mayhem13]

Thanks Barry.

 

The room is 8' - 240cm - high.

 

In fact this thread has caused me to revaluate my existing set up. At the moment I'm just using a radio shack meter and warble tones from 200Hz downwards. Whilst I understand the limitations of meters (and microphones) they are useful, along with, as you say, listening, to give a fair idea of what is going on.

 

Microphones are only limited to their intended use, and for that purpose they can be an extemely, IMO invaluable tool in understanding your space and speaker system.

 

Truth be told, within every audiophile is a tweaker who enjoys moving things around an unreasonable amount of times searching for audio nirvana.......and when he can't get there as so many other listeners and practicing Buddhists, he replaces a piece of gear that promises just that........or finds a new Guru to advise him on his quest. What a shame as the tools are readily available to bypass the mysticism. Aaaaaah.....the ever powerful attraction to the unknown. Seems to be part of the human condition.

 

Once one recognizes that every listening space is unique in its furnishings and surfaces and that every speaker has a uniques radiation pattern and phase behavior, a reasonable man would conclude that there simply cannot be a set procedural method for speaker placement. Not my conclusion, just good ol algebra.....when there's too many variables in an equation, there are multiple possible results. You need to fill in some of those X's an Y's with data. This can be accomplishes with measurements, specs, or reasonable conclusions.

[4est]

The Buddhist would more likely practice acceptance. A rather offensive statement regardless.

 

Truth be told, within every audiophile is a tweaker who enjoys moving things around an unreasonable amount of times searching for audio nirvana.......and when he can't get there as so many other listeners and practicing Buddhists, he replaces a piece of gear that promises just that........or finds a new Guru to advise him on his quest. What a shame as the tools are readily available to bypass the mysticism. Aaaaaah.....the ever powerful attraction to the unknown. Seems to be part of the human condition.

[bdiament]

Thank you 4est,

 

The Buddhist would more likely practice acceptance. A rather offensive statement regardless.

 

Agreed.

 

Best regards,

Barry

Soundkeeper Recordings

Barry Diament Audio

[Hipper]

Truth be told, within every audiophile is a tweaker who enjoys moving things around an unreasonable amount of times searching for audio nirvana.......and when he can't get there as so many other listeners and practicing Buddhists, he replaces a piece of gear that promises just that........or finds a new Guru to advise him on his quest. What a shame as the tools are readily available to bypass the mysticism. Aaaaaah.....the ever powerful attraction to the unknown. Seems to be part of the human condition.

 

Actually part of the human condition is to want to do better. It also seems sensible to listen to people that have advice to offer.

[mayhem13]

Actually part of the human condition is to want to do better. It also seems sensible to listen to people that have advice to offer.

 

Not sure of the sensibility side of it......there's plenty of examples throughout history where that wasn't exactly a best practice...........but hey, whatever works for ya!

[Hipper]

The Thirds Speaker Set Up

 

Following advice on here from Barry Diament:

 

Setting up your monitoring environment

 

I set up my speakers in ‘The Thirds’ arrangement and ask for comments from those that have also done this.

 

I use only redbook Cds. I am getting used to the new sound and enjoying it, particularly the new information that can be heard from old favorites, caused principally by the greater separation of each song‘s parts, for example harmonies and rhythm guitar. However I’m finding that there are inconsistencies.

 

On some recordings, the speakers completely disappear and everything seems nicely set out. However, other songs have vocals more set back but still clear whilst things like rhythm guitar are quite prominent in the left or right speakers. For yet others, the vocals seem too set back and less prominent .

 

Is this a fault of my set up or is this more about quality of recordings?

[bdiament]

Hi Hipper,

 

The Thirds Speaker Set Up

 

Following advice on here from Barry Diament:

 

Setting up your monitoring environment

 

I set up my speakers in ‘The Thirds’ arrangement and ask for comments from those that have also done this.

 

I use only redbook Cds. I am getting used to the new sound and enjoying it, particularly the new information that can be heard from old favorites, caused principally by the greater separation of each song‘s parts, for example harmonies and rhythm guitar. However I’m finding that there are inconsistencies.

 

On some recordings, the speakers completely disappear and everything seems nicely set out. However, other songs have vocals more set back but still clear whilst things like rhythm guitar are quite prominent in the left or right speakers. For yet others, the vocals seem too set back and less prominent .

 

Is this a fault of my set up or is this more about quality of recordings?

 

The clearer the window, the more you are able to see through it.

 

I have often mentioned that one of the best ways I know to evaluate the transparency/neutrality/resolution of a system is by the degree of difference one hears between recordings. In my experience, every master recording sounds quite different from every other master recording. When the playback system starts to provide commonalities between recordings, it is a sign of a coloration - a departure from transparency, neutrality/resolution. In other words, if there is a common character to the treble between different recordings, something in the system (and/or its setup) is responsible. Colorations are applied to everything that passes through the system. In the absence of colorations (or when they are minimized) the sonic differences between recordings are at their greatest.

 

I would suspect that if minimally mic'd recordings allow your speakers to "disappear" in the current setup, what you hear with other recordings is simply the bad engineering that is unfortunately, all too common on so many of the records we love.

 

But please don't simply take my word for this. Listen to as many different recordings as you can, particularly well made ones, including "purist" oriented ones (Keith Johnson's work comes to mind). You may hear it as I do or you may hear it differently. If the former, you'll notice that recordings made with multiple closely placed microphones (most typical studio recordings) are not capable of delivering the same sort of soundstage and naturalness (and real *stereo*) as other recordings are.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

 

P.S. I would add that the setup I've recommended in the article is a *variation* on a thirds arrangement and is not literally a thirds arrangement. That is, the speakers *touch* the 1/3 points but are not centered on them.

[Melvin]

The Thirds Speaker Set Up

 

Following advice on here from Barry Diament:

 

Setting up your monitoring environment

 

I set up my speakers in ‘The Thirds’ arrangement and ask for comments from those that have also done this.

 

I use only redbook Cds. I am getting used to the new sound and enjoying it, particularly the new information that can be heard from old favorites, caused principally by the greater separation of each song‘s parts, for example harmonies and rhythm guitar. However I’m finding that there are inconsistencies.

 

On some recordings, the speakers completely disappear and everything seems nicely set out. However, other songs have vocals more set back but still clear whilst things like rhythm guitar are quite prominent in the left or right speakers. For yet others, the vocals seem too set back and less prominent .

 

Is this a fault of my set up or is this more about quality of recordings?

 

Hi Hipper,

 

I've used Barry's loudspeaker setup advice with great success also. In fact I try to "steal" as many tips as I can from the man ;-)

 

It's amazing what can be accomplished with a well set-up room. Enjoy your new-found sound.

[MikeJazz]

 

The clearer the window, the more you are able to see through it.

 

I have often mentioned that one of the best ways I know to evaluate the transparency/neutrality/resolution of a system is by the degree of difference one hears between recordings. In my experience, every master recording sounds quite different from every other master recording.

P.S. I would add that the setup I've recommended in the article is a *variation* on a thirds arrangement and is not literally a thirds arrangement. That is, the speakers *touch* the 1/3 points but are not centered on them.

 

I recently follow Cardas recommendation and have been listening to my Quad ESL much further into the room at about 157 cm from the back wall.

Differences are substantial, but yes, not all records sound good. Al least now, some sound divine!

 

Yet I am reviewing the nice Barry guide, and I want to try some tips, especially about toe in...

Also, my sofa seating is less flexible that the loudspeaker...sofa is big and cannot move further back...so there is some room for experimentation moving the speakers...

 

Question to Barry: do you think toe in is also important for panels/dipoles? because one guy that is used to install quads told me they were made to work with no toe in...

 

I found this very amusing as it reflected my experience also "It was quite a magical experience when I first encountered this kind of speaker placement"

I remember the impact on my previous modest Rega Naos. Instead of the subjective idea that they would produce less bass, and that I would have to compensate by higher volume, the opposite happened. I had to lower the volume, as now everything was more precise, including the bass...

 

Now with the dipoles the ideal placement is closer to the back wall, but still not enough on WAF...

[bdiament]

Hi Mike,

 

...Question to Barry: do you think toe in is also important for panels/dipoles? because one guy that is used to install quads told me they were made to work with no toe in...

 

I found this very amusing as it reflected my experience also "It was quite a magical experience when I first encountered this kind of speaker placement"

I remember the impact on my previous modest Rega Naos. Instead of the subjective idea that they would produce less bass, and that I would have to compensate by higher volume, the opposite happened. I had to lower the volume, as now everything was more precise, including the bass...

 

Now with the dipoles the ideal placement is closer to the back wall, but still not enough on WAF...

 

In some respects, I think toe-in can be even *more* important for dipoles than for quasi-omni monopoles (i.e., box speakers). It really depends on the dispersion characteristics of the individual speaker in the treble and also to a degree, in the midrange. I'd certain suggest experimentation.

 

I would also submit that ideal placement for dipoles is *not* closer to the back wall. At least not in my experience.

I have often said "Every foot from the wall adds at least $1000 to the sound." ;-}

 

Many erroneously believe that getting closer to the wall produces more bass. It does not. It produces more *room*. The low frequency resonance of the room is not the same as the bass in the recording. It isn't even the same pitch! And, it is out of time with the record. Moving the speakers away from the wall reduces the effects of the room but allows the bass in the recording (in terms of quantity and in terms of pitch) to be more easily heard. And, unlike the room boom, it is in time and it is in tune.

 

I would definitely experiment with toe-in. If you hear no change, it doesn't matter. If you happen to notice an increase in apparent solidity of images, in the overall "focus" of the soundstage, then it is well worth the effort.

Please post about any experiments you might do. I have not heard ESLs in a long while and would be curious to know if you find any benefit from toe-in.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[4est]

Quad ESL are unusual in that they are a dipole point source. They have a built in time delay whereby the center of the panel has a bulls-eye. The signal originates in the very center, with rings progressively delayed outward by the step up transformer. It is pretty ingenious, and works a treat. You will want toe in. Play with it-a lot. They are one of the most transparent speakers ever produced. Your efforts will be rewarded most likely.

[MikeJazz]

Quad ESL are unusual in that they are a dipole point source. They have a built in time delay whereby the center of the panel has a bulls-eye. The signal originates in the very center, with rings progressively delayed outward by the step up transformer. It is pretty ingenious, and works a treat. You will want toe in. Play with it-a lot. They are one of the most transparent speakers ever produced. Your efforts will be rewarded most likely.

 

Yes, it's a reward...it's a window to the music...Jeff Buckley is playing "Lilac Tree" and is really a joy be able to "look" to that guitar playing...the orchestration of those guitars in this track is amazing!

 

but sometimes also a worrying affair...

The great dynamics of Rite of Spring can really be challenging...and for twice the amp shut down due to Quad's protective circuit...

[Hipper]

The clearer the window, the more you are able to see through it.

 

Thanks Barry. That is a nice way of looking at the situation.

 

I'm used to a wide flat image with speakers close to both walls. Most of the music I liked sounded good or at least OK and I enjoyed listening but I knew I hadn't done things properly on the room treatment side. I've now addressed that to good measure and whilst resetting everything thought I'd try your suggestions. The best measurements are in fact still with speakers far apart and close to the walls. In fact I measured for both options with the intention of giving 'The Thirds' a fair hearing before probably going back to what I'm used to.

 

Interestingly familiar songs in many cases sound quite different but the extra dimension (depth) offers new insight. I'm also getting detail that I only knew from headphones and it is a real joy to hear this through speakers. I was always told this was not possible.

 

I wonder if it will change my musical tastes?

 

Thanks Barry for all your advice which I've come across on many threads and forums. It's much appreciated.

[bdiament]

Hi Hipper,

 

Thanks Barry. That is a nice way of looking at the situation.

 

I'm used to a wide flat image with speakers close to both walls. Most of the music I liked sounded good or at least OK and I enjoyed listening but I knew I hadn't done things properly on the room treatment side. I've now addressed that to good measure and whilst resetting everything thought I'd try your suggestions. The best measurements are in fact still with speakers far apart and close to the walls. In fact I measured for both options with the intention of giving 'The Thirds' a fair hearing before probably going back to what I'm used to.

 

Interestingly familiar songs in many cases sound quite different but the extra dimension (depth) offers new insight. I'm also getting detail that I only knew from headphones and it is a real joy to hear this through speakers. I was always told this was not possible.

 

I wonder if it will change my musical tastes?

 

Thanks Barry for all your advice which I've come across on many threads and forums. It's much appreciated.

 

As I don't know anything about your room, how it is set up or what sort of treatments you are using and how they are implemented, all I can think is, if you are getting better measurements with the speakers closer to walls (where they excite the room more), I'd reconsider the measurement method. If an accurate one, properly implemented, it *should* be revealing the added energy contributed by the room. (Of course, you did not define "best" measurements. If the added energy is preferred, that is something else -- I would never argue with whatever brings anyone their listening pleasure. But if by "best" we're talking about more accurate to the source, I would definitely question things.)

 

Also, are you just measuring frequency response or is a time response (including decay time) included in the measurement set?

What I always say with regard to simple frequency response measurements is one must be mindful of the assumptions being made, which include:

1. the idea that what the (one-eared) mic "hears" will represent what a (two-eared) human would hear. The accuracy of single mic measurements would, in my opinion, be beyond question IF the humans involved in the subsequent listening had extraordinarily narrow heads and a single ear in the middle of their face. ;-}

2. perhaps even more importantly, that an amplitude-based measurement (i.e., frequency response) will show anything like an accurate picture of a time-based problem (room issues). A frequency response measurement reveals *some* of the symptoms but says nothing about the root issue manifesting the symptoms, which is based -- and can only be measured -- in time.

 

Of course, as a curiosity, it is something else altogether and I can understand the interest in seeing a frequency response taken in one's room. I raise what I did because all too often I see folks confusing this one view with the much larger overall reality. To overvalue what such measurement actually tell you is to hold an elephant by the tail and declare it a snake. ;-}

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[Hipper]

Hello Barry.

 

This is a picture of my current speaker set up:

 

 

The speakers are VMPS RM30Ms with side firing woofers. My room is 420cm x 386cm x240cm high. I use the 420cm wall for the speakers. Speakers were set to 140cm and 129cm from the walls, ears 129cm from the back wall. I then measured the distance to my ears and found, presumably because rooms are not exact shapes, I needed to move one speaker 4cm in to have the same ear distance. Toe in is nearly to the centre of the back wall.

 

I measure using REW and a microphone placed where my ears will be - when measuring the left speaker the mic is placed where my left ear will be.

 

My definition of 'best' is a flat response at my ears. That is, assuming the speakers were designed with flat response, I would like that to get to my ears without interference from the room and its contents. This doesn't appear possible even with nearfield type listening but it seems a desirable aim.

 

I look at these measurements as a guide, not definitive, for a number of reasons. Firstly as you say, microphones cannot act like ears with a head, and secondly, traffic and other noise affects them. This was clearly evident on spectrograms and waterfall plots. 50Hz and below I can’t measure properly at all because of this, so I used 50-500Hz to help with speaker placement.

 

The first step was installing the soffit bass traps and panels on the back wall (the other material is Auralex foam, left over from my previous efforts). I then positioned the speakers and chair, carrying out many positioning and measurements to get the best compromise. With all these measurements a consistency appears and so I’m pretty confident in the positioning. Even the best positions have problems - suck outs, peaks.

 

Once I’m satisfied with the speaker positions I found the best locations for the panels and diffusers, again using REW but also my ears. I then listened. However things were not right. In particular some vocals (Alison Krauss) and instruments (saxophones, violin) were harsh at times, and the higher frequencies also seemed a bit messy. Now I’ve always had my gear located between the two speakers and following advice and considerable effort I moved them to one side. Straight away there was a 3dB loss in energy at the higher frequencies (I don’t really understand why!). In addition I had some panels (GIK 244s which had scatter plates installed) at the side wall reflection points and it turns out the reflections off these were causing the muddying. I swapped them round with other panels which only absorbed. These actions have solved the harshness and muddying and as a bonus allowed the bass to be more prominent.

 

I now go down a road I know you aren’t fond of - an equaliser! I know that I’m trying to solve problems that ideally should be sorted some other way, but it seems to work for me. Using REW I try to get the flattest frequency response for the full range.

 

I can bypass the equaliser so I played Cds in bypass but it just didn’t work. With the equalised flat response the listening is much nicer. For example, there are peaks of 7dB or so from both speakers at around 4.5kHz and 5.6kHz. I don’t know why but removing those peaks makes for more pleasant listening.

 

Here’s an SPL reading from REW for the left speaker with 1/24 smoothing. The red is with bypass, the blue with the equaliser.

 

 

There are still big problems, notably nulls at 315Hz and 400Hz but I can't do much about them. If I move the speakers to address that, some other problem occurs! Sure I could try and identify each one and find a solution but.... Maybe one day.

[bdiament]

Hi Hipper,

 

Just saw your latest post. I'm sorry I don't have time for a proper response right now, but I didn't want you to think I was ignoring your post. Will get back to you on this within the next couple of days.

 

Best regards,

Barry

http://www.soundkeeperrecordings.co

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[bdiament]

Hi Hipper,

 

I've been trying to find an anechoic frequency response graph for your model speakers on the Web but so far, have not had any luck. Reading your post, a number of questions come to mind, the first of which was "How flat are the speakers themselves?" But leaving that aside for the moment, as I think there are more important things than frequency response, some other questions involve the placement and the treatments.

 

First, when you say the speakers are "set to 140cm and 129cm from the walls", exactly which point on the speaker is at this distance from each wall? My recommendation is to use the front, inside corner (the corner toward the center) as the point on the speaker to place at the 1/3 dimensions. When toeing-in, rotate the outside of the speaker around this point. In other words, once initially placed, the front, inside corner remains at the 1/3 points, while the front outside corner is rotated forward (toward the listener).

 

As to listening position, I would place this relative to the loudspeakers and not at its own 1/3 point. Once the speakers are in position, measure the distance from center of the left speaker's front baffle to the center of the right speaker's front baffle. Add ~10% to this to get a starting point for the distance the listening position should be from either speaker. In other words, if the center of the left speaker's front baffle measures say, 150 cm from the center of the right speaker's front baffle, start with a listening position that puts your ears ~165 cm from the front baffle of either speaker.

 

While seated in this position, play a very well made recording (one done with few microphones, resulting in a very coherent soundstage) and while listening, lean forward and backward from the listening position. Try to keep your head and ears at a constant angle (level) -- as if your chair was on a track, slowly rolling toward, then away from, the speakers. If all is well, the effect should be much like rotating the focus on a camera lens to either side of sharpest focus. As you narrow the motions, you should find the position at which everything "snaps" into its sharpest focus.

 

Now, for the above to occur, there are certain prerequisites:

1. Speaker position must be optimized.

2. Room acoustics must be properly treated (more on this below).

3. The recording must be one that actually contains a focused image, i.e., it must be a coherent recording.

4. The components, including speakers, source, electronics and ancillaries such as cabling and AC power must be up to the task.

 

I would note that the dimensions of your room, with the length and width comprising a somewhat squarish shape, as opposed to a longer rectangle, make for a bit more stringent requirement for proper room treatment. This is because with this sort of shape, the resonant modes of the length dimension and the width dimension are not far apart (the fundamentals being at ~82 Hz and 89 Hz, their significant harmonics being at the first two or three multiples of these). All this means is proper room treatment is even more essential here than in a more rectangular room.

 

Before I go on to room treatment, I would note your comment about placing your measurement microphone at the position of your left ear when measuring the left speaker. One other reason (of the many) I do not place much weight on frequency response measurements of this sort is that there will never be a situation in your real life listening when your left ear will hear only the left speaker. Or when the left speaker will be playing uninfluenced by what the right speaker is doing.

 

As to the room treatment, can you describe the internal construction of the soffit (and any other) bass traps?

If they were perfect bass traps, what I see across the top of the front of the room will address the vertical mode only (which I would take to be ~143 Hz at the fundamental). Again, even if perfect, this arrangement isn't going to touch the modes for the length and width dimensions. If that is Auralex I see on the bottom in the front corners, it too is doing nothing at all for the room modes.

 

Further, I see a pair of diffusors in the center of the wall behind the speakers. While we'll often see photographs of recording studios with diffusors near the speakers, I would submit that listening to the work from such studios will not impress. Why? Because in addition to the room's resonant modes in the bass (up to ~300 Hz), rooms have treble issues caused by reflections of sounds from the loudspeakers and reflections of sounds that have bounced off walls and other objects in the room. I'll address them separately.

 

Every speaker radiates sound in all directions, particularly low frequency sounds. Prove this by standing directly behind your speakers while music is playing. Walk around the speakers too. Is there any position where you could not tell whether the music was on or not? I'd bet there will not be. Now, some of the sound you hear is forward radiation from the speakers that has reflected from elsewhere in the room. But if you take the speakers outdoors, to a large field, far away from reflective surfaces, I'd be willing to bet you'd still hear sound from them as you walked around the speakers. With this in mind, we realize the room boundaries nearest the speakers, primarily the wall behind them and walls to the sides but also the floor and to a lesser degree the ceiling (unless the speakers are planar dipoles which don't radiate as much to the sides or vertically), will all produce reflections of the direct sound from the speakers. All of these *will* arrive at the listener's ears, slightly after the direct sound from the speakers does. These are the early reflections. They combine with the direct sound of the speaker, causing frequency response irregularities (lots of peaks and dips), reinforcing some frequencies and causing others to cancel to varying degrees. In addition, they smear the signal in time, causing it to lose focus, causing low level detail to be obscured, causing images to lose accurate placement on the soundstage and causing the soundstage itself to collapse in all dimensions.

 

The deleterious effects of early reflections can easily be completely removed. The simple solution is to absorb them, so they never reach the listener, never combine with the direct sound, never cause any harm. There is one early reflection point on each room boundary. My article Setting up you monitoring environment speaks about this and how to address it. Essentially, one needs to find the reflection points (in a system with two loudspeakers, there will be two points on each room boundary) and place absorbent material at these points. It is important to realize that *only* these points need absorption. We'll often see rooms with foam padding all over the place and it only takes a few seconds in one of these rooms to sense how unnatural and uncomfortable they are. Absorption can take the form of anything soft, such as a wall hanging one enjoys looking at. On the floor, a carpet or area rug can cover the reflection points for both speakers in one shot.

 

Okay, so with the idea in mind that early reflections are bad for the sound and are best absorbed so they never reach the listener, one must ask what happens when a diffusor is placed near the loudspeakers. A diffusor is designed to scatter the sounds impinging on it in all directions. Placed where an early reflection would occur, rather than absorb (and hence remove) that reflection, a diffusor will *guarantee* said reflection gets to the listener!

 

So are diffusors useful in listening rooms? Yes, they most certainly are but *not* near the loudspeakers and not where any early reflection point might occur. We need to remove the early reflections but ideally, we also want to promote the late reflections. Late reflections are those that have already been around the room. They are well separated in time from the direct sound from the loudspeakers and also, having "bounced" already, are significantly diminished in energy. One of the reasons those over-foamed rooms are so uncomfortable is because the late reflections have been removed. So, I'd keep diffusion well away from the loudspeakers, oriented 180 degrees opposed to any absorption. (Face absorption toward the speakers, face diffusion away from the speakers.) In fact, I rank diffusion as last in importance in a proper room treatment. Ideally it is included but only after room modes in the bass and early reflections in the treble have been fully addressed.

 

So in conclusion, my suggestions are these (for starters):

1. Move the speakers as outlined above.

2. Move the listening position as outlined above.

3. Move the diffusors elsewhere and move the absorbing foam (if in fact it is absorbent and not at all reflective in the treble -- in my experience a lot of "acoustic foam" does a lot more harm than good -- foam must be *very* soft to work as an absorber... otherwise, hanging a bath towel can be more effective).

4. Re-examine the bass treatments to ensure they are doing what you want them to do. I'd also re-examine placement of bass treatments in the room.

 

Room issues are time-based. Taking a frequency response can only show symptoms, not causes. Using EQ on room issues is like fixing a broken arm by changing hats. (It might make one feel better and I'd never argue with that. But it doesn't fix the problem.) It is the direct sound we hear first and the direct sound that determines the overall color of a system. If your mic/software isn't separating the direct sound from the cumulative sound of direct + room, it is not giving an honest picture of what is happening. And all this is still assuming the speakers themselves are capable of delivering a flat response. The fact that you mention even near-field listening isn't working right suggests it isn't all the room. (The close proximity of the equipment on the side seems like it would create reflection issues too.)

 

Just some thoughts, as always from my own perspective (the only one I have access to ;-}).

Hope there is something here that might help.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[Hipper]

Hello Barry.

 

Firstly thanks again with the time you are putting in on this discussion. Hopefully it will help others too.

 

Unfortunately because the speaker designer, Brian Cheney, died late last year, all the info relating to VMPS speakers seems to have gone. My RM30Ms were described as ‘flat down to the low 30s Hz’. They also have so called L-pads which allow for some adjustment of the tweeter and midrange panels. There is an Audio Circle for VMPS:

 

VMPS Speakers

 

The set-up guide in the stickies gives a bit more info. I’ve no reason to think my speakers are misbehaving, particularly as if they are, they both are, which would be a coincidence.

 

A bit more background to my room. It is part of a flat (apartment). Walls are concrete, floor is wooden sprung with a sonic insulating mat to reduce sounds going to my neighbours below and carpet tiles on top of that. Ceiling seems like plasterboard. It is really a study with shelves of books at the top three feet on all but the front wall, a desk and computer screens in the back right corner, and a door in the back left corner.

 

For the last few years I used Auralex foam, practically all on the front wall. It sounded good to me at the time (and certainly better then the nothing I had before) but because of threads like this I began to question it. I therefore contacted GIK Acoustics, and advice from Alexander Reynolds within the budget I allowed led to my current set up using seven of their Soffit Bass Traps (I don‘t know exactly how they are constructed but they seem to be a wooden frame with solid ends containing some absorbent material and space), said to absorb down to 40Hz, two Monster panels and two 244 panels, both absorbing down to 80Hz, and two QRD diffusers. Ideally soffit traps should also go in the front bottom corners but can’t, so I put Auralex foam (absorption down to 125Hz) at those points. There is a Soffit Trap in the middle of each of the side wall/ceiling corners. There is also Auralex corner foam on the back wall/ceiling corner but it’s not practical to put anything on the back wall/side wall corners.

 

I did try the Soffit Traps in other locations - front wall on the floor/wall corner, the bottom front/side wall corners (although as I said I can’t fix them there permanently), the back wall/side wall corners. I think I have the best arrangement which can only be improved by adding more.

 

In the photo in my previous post you see two monster panels to the left and right. They deal with first side wall reflections from both sides of each speaker. The 244 panels are on the back wall behind my chair. That is my current arrangement but I tried numerous positions to see how they measured AND sounded.

 

I set out to deal with bass problems/room modes first. That’s why when measuring I did it only up to 500Hz.

 

I tried a range of positions based on two main ideas, the wide flat image I was used to, and ‘The Thirds’. I initially measured for the left speaker only and from that then tried positions that were best for both right and left speaker. I also moved the seat position to see what effect that had. I tried ‘The Thirds’ using the measurements from the inner corner, as you suggest, but found that in fact the best position was the driver centres at 140cm and 129cm. As I mentioned, I had to include toe in from the start because my speakers have a side firing woofer and toe in makes a difference to the measurements.

 

It was a complicated business and took me a good two months to get where I am now. Here is a plan of speaker positions I tried:

 

 

The dots mark the left speaker position and those with the red circles had the best (flattest) measurements.

 

I knew because of my room dimensions that 40Hz and its multiples, 80Hz and 160Hz would be problems. Measurements were complicated by traffic and other noise, particularly around 40Hz and 50Hz, but it’s clear, from measurements and my ears, that the room mode problem has been reduced significantly by both the bass traps and positioning. It translates as markedly more bass (one of the somewhat unintuitive consequence of absorbing room modes) and of course it being tighter and more accurate.

 

Incidentally I also tried different speaker heights and different ear heights whilst listening. The current distance between the left and right speaker centres is 141cm, speaker driver to my ear 145cm. The drivers on my speakers do integrate even at that short distance.

 

So, the reason for my current positioning of bass traps, speakers and chair is flattest response up to 500Hz. I always understood that this is the most important to get right. I walked round the room to listen to bass and found that there is still significant volume in the front corners but not so in the back corners.

 

Also as I walked round the speakers I also listened for high frequencies (HF). Right behind each speaker there was little HF but standing behind and between them there was a bit more but only when in front of them was there a significant amount.

 

In locating the diffusers, which was the last thing I did, I tried various locations including back wall, side walls and different positions on the front wall. Where I have them now sounded best. What they added was a sort of focus, to vocals and acoustic guitar for example. It’s a strange experience as I’m not familiar with using them and at first I wondered if they did anything at all. I am not really sure how they work (I understand the scattering effect but these QRD type diffusers are a bit more sophisticated are they not. GIK call theirs Q7d and claim they scatter evenly from 350Hz to 3kHz).

 

For the higher frequencies I’ve drawn a ray diagram to try to work out how they are reflected. I don’t think I hear any first reflections (unless any come from the ceiling). Whilst later reflections can come from anywhere I think the most likely source is the front wall/window. However when I experimented with absorbent panels there it had little effect. This ray diagram isn't for my current positioning.

 

 

On the power conditioning front I use a Shunyata Hydra.

 

Just to give you a bit more idea of what is going on here is a waterfall plot and spectogram from the equalised measurement of the left speaker:

 

 

 

The noise at 149Hz is amplifier hum. This happens very occasionally. The rest of the noise is presumably road traffic and maybe building work going on half a mile down the road.

 

I will try the ‘chair on a trolley’ test with a good recording but if I now start moving my chair I’ll surely be compromising the bass sounds.

[bdiament]

Hi Hipper,

 

We may just have different perspectives on how to go about addressing a room and what we each seek.

 

My own take is that focusing on frequency response can very easily cause one to lose track of other aspects of the sound which might have more audible consequences. (In my view, the more one looks at frequency, the less they will see the time aspect.) Just one example can be found in the frequency specifications from the manufacturers of "acoustic treatments". I find the claims, regardless of how they measured to achieve them, tend to be (to put it nicely) quite exaggerated when applied to the real world. Claims that acoustic foam does anything at all for the bass, even "down to 125 Hz" are not born out in my experience, unless one is using an impractical thickness of said foam. Many devices sold as "bass traps", in my experience, create a change but are not, in the end, what I'd call effective.

 

I would *always* start trapping in the vertical corners of the room as these will address larger swaths of room mode issues than horizontal traps (which can be fine but only when the vertical ones are all in place). If I used foam at all (for acoustics, I don't), it would be to address treble issues at reflection points. In my experience, it is effectively transparent in the bass. As far as diffusors, there are many designs but I would reserve any call on sophistication; to me, they either diffuse effectively or they don't. The former can be achieved quite well with a basic semi-cylinder shape too. (Placing them near the speakers will indeed increase the apparent treble. If this brings pleasure, that is a good thing. To me, the increase in apparent "focus" is really a tonality change while at the same time, depth and low level detail are --to my ears-- actually obscured.)

 

A question: Is the waterfall graph taken after the treatments? (It looks like a "before" shot to me.) I know you mention it is a non-equalized view but I'm looking at time, which I find of greater concern than amplitude. An equalizer can diminish the symptoms but it will do nothing at all to shorten the decay time at those frequencies. (You can hide some of the symptoms by not introducing those frequencies but at that point, the response from the speakers is skewed to a point I wouldn't want for my own listening.) Proper room treatment will shorten those decay times, with no need for EQ. The speaker response can be left unaltered so it can perform at its best and the room will not color the sound. I wonder if some of that lag in the 140-150 Hz region is the vertical resonance of the room (~143 Hz) too.

 

All that said, if you are pleased with how things sound, I'd never argue. All I'm saying is that if there are time lags, which the waterfall plot seems to indicate, then things can be better than they are now. IF that indeed is taken with the treatments in place, I would say the treatments are not doing their job effectively. This could, if the traps are a good design, be simply because they need to be relocated.

 

As always, this is just my own point of view and how *I'd* approach treating a room. There are many paths to listening pleasure, many of which are different from what I choose for myself or my clients. The key is to find what works for you.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[Hipper]

The spectrogram and waterfall plot are with EQ and all treatments in place, so in fact, my current listening set up.

 

In the spectrogram, the middle bit, from zero seconds and upwards, is the test signal used for measuring. Anything before the zero (below the signal), the minus figures, must be noise of some sort. Therefore some of the spectrogram after the signal must also be noise. Of course it's difficult to say how much.

 

The waterfall plot gives a better idea but is not conclusive.

 

The 149Hz problem is definitely amplifier hum as it is the only time that this has happened when I measured. You can see on the spectrogram that it is a consistent strength before and after the test signal.

 

I made a record of just noise earlier - no speaker output:

 

 

I understand what you say about time lags/resonance. My difficulty with these plots is distinguishing background noise from signals generated by the speaker. In the end, that is why actually listening is the decisive factor.

 

Today I was listening and amongst other things, following advice from Jim Smith in his book 'Get Better Sound'. One of his suggestions is to use a CD - he uses The Chieftains 'Tears of Stone' - to 'voice' the system. For example he says track 2 has a run of three bass notes at 0.31 which are around 63, 50 and 40 Hz and they should sound practically the same dB. In my case 50Hz is slightly less than 40Hz, and 63Hz is slightly less than 50Hz. Of course this is an area I have difficulty measuring because of the background noise (by the way I don't really hear this background noise but the mic picks it up).

 

I am generally pleased with the sound - some classical music I was listening to today was beautiful and the speakers truly disappeared. There are however still little problems, such as the bass mentioned above, and some harshness with violins on a recording, which of course could be the recording (I can also hear what sounds like the violinist taking in breath? Perhaps the recording is overly bright.).

 

The GIK Soffit Traps have made a real difference. I regret I did not measure the room before installing them. Perhaps I do need more bass trapping and should look again at the diffusers. I would love it to be able to not use EQ.

 

Thanks again Barry.

[bdiament]

Hi Hipper,

 

...The 149Hz problem is definitely amplifier hum as it is the only time that this has happened when I measured. You can see on the spectrogram that it is a consistent strength before and after the test signal...

 

To my eyes, the fundamental height resonance is visible too.

 

 

...I understand what you say about time lags/resonance. My difficulty with these plots is distinguishing background noise from signals generated by the speaker...

 

The key thing the waterfall plot reveals is neither background noise or signals generated by the speaker. It is showing the room ringing (and perhaps, to a lesser degree, some resonances in the speaker, causing its cabinet to sing).

 

 

...Today I was listening and amongst other things, following advice from Jim Smith in his book 'Get Better Sound'. One of his suggestions is to use a CD - he uses The Chieftains 'Tears of Stone' - to 'voice' the system. For example he says track 2 has a run of three bass notes at 0.31 which are around 63, 50 and 40 Hz and they should sound practically the same dB...

 

I would suggest a *variety* of reference recordings rather than one -- unless you were present at the recording session and stood at the position of the microphones. Even so, I'd still suggest a variety. In my opinion, to suggest what the notes in a given recording should sound like, again, one would have had to have stood at the microphone position during the recording and also have intimate knowledge of how the recording was captured. Failing this, there is only speculation (useful as it may well be). Personally, I would be hesitant to use any recording made with multiple, closely placed microphones for anything but a quick check -- never as a reference.

 

 

...I am generally pleased with the sound - some classical music I was listening to today was beautiful and the speakers truly disappeared...

 

Ultimately, *that* is what counts.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[Jim Smith]

Hi Hipper,

 

 

I would suggest a *variety* of reference recordings rather than one -- unless you were present at the recording session and stood at the position of the microphones. Even so, I'd still suggest a variety. In my opinion, to suggest what the notes in a given recording should sound like, again, one would have had to have stood at the microphone position during the recording and also have intimate knowledge of how the recording was captured. Failing this, there is only speculation (useful as it may well be). Personally, I would be hesitant to use any recording made with multiple, closely placed microphones for anything but a quick check -- never as a reference.

 

 

 

Barry,

 

I have been supportive of your posts as a speaker set-up expert. First - because they are generally correct, and second, because they are helpful.

 

I never suggested the Chieftains cut as the reference for recordings. I did suggest it as a simple way to determine if bass notes at about the third octave spacing from about 40 through 180 could be checked by people who do not have any test equipment other than their ears.

 

I happened to notice the various bass notes on cut 2 were reasonably similar in level. That's the entire point. I'd never suggest this was a reference for sound.

 

Thousands of readers from around the world have used this simple check to see if they have a reasonably smooth bass region. Furthermore, I suggest what they might do if there is a problem.

 

My position is that if you don't get the bass region (say 30-200 Hz) reasonably smooth, you'll never be as happy with your music reproduction as you would be if that area was addressed first.

 

"In my opinion, to suggest what the notes in a given recording should sound like, again, one would have had to have stood at the microphone position during the recording and also have intimate knowledge of how the recording was captured."

 

Isn't dissing what I suggest without knowing the context somewhat similar to recommending aspects of a recording when you have no idea how it was made?

 

I am still a fan of your posts, but thought I needed to speak up on this one.

[bdiament]

Hi Jim,

 

Barry,

 

I have been supportive of your posts as a speaker set-up expert. First - because they are generally correct, and second, because they are helpful.

 

I never suggested the Chieftains cut as the reference for recordings. I did suggest it as a simple way to determine if bass notes at about the third octave spacing from about 40 through 180 could be checked by people who do not have any test equipment other than their ears.

 

I happened to notice the various bass notes on cut 2 were reasonably similar in level. That's the entire point. I'd never suggest this was a reference for sound.

 

Thousands of readers from around the world have used this simple check to see if they have a reasonably smooth bass region. Furthermore, I suggest what they might do if there is a problem.

 

My position is that if you don't get the bass region (say 30-200 Hz) reasonably smooth, you'll never be as happy with your music reproduction as you would be if that area was addressed first.

 

"In my opinion, to suggest what the notes in a given recording should sound like, again, one would have had to have stood at the microphone position during the recording and also have intimate knowledge of how the recording was captured."

 

Isn't dissing what I suggest without knowing the context somewhat similar to recommending aspects of a recording when you have no idea how it was made?

 

I am still a fan of your posts, but thought I needed to speak up on this one.

 

I apologize if my words came across as dissing your suggestion. That was not my intent and again, I'm sorry if they read that way.

 

I understand now the recommendation was for a specific grouping of sounds, which I'm confident you are familiar with when heard on a well set up system. Please forgive my misreading of Hipper's post as the recording itself being presented as some sort of reference. That is not how I'm reading your words, which I hope I'm reading correctly.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[bdiament]

I must say I feel like a real putz for insulting Jim Smith, one of the good guys in this hobby of ours.

This was not at all my intention and I certainly don't want to be one of those folks on Internet audio fora that I frequently complain about.

 

Must be careful about how posts are worded.

I'm really sorry Jim.

 

Best regards,

Barry

Soundkeeper Recordings

The Soundkeeper | Audio, Music, Recording, Playback

Barry Diament Audio

[Jim Smith]

I must say I feel like a real putz for insulting Jim Smith, one of the good guys in this hobby of ours.

This was not at all my intention and I certainly don't want to be one of those folks on Internet audio fora that I frequently complain about.

 

Must be careful about how posts are worded.

I'm really sorry Jim.

 

 

No problem at all.

 

Thanks for your comments.