Defining the Sweet Spot

James Tanner · « **on:** 28 Feb 2010, 01:35 pm »

Hi Folks

Since I decided to try the Model 10 electrostatic speakers from Roger Sanders I have been reading some of the reviews of earlier works when Roger was at Inner Sound. There really seems to be a controversy about his thoughts on the speaker/room interface.

His contention is that the loudspeaker should be designed to have a very narrow dispersion or polar response because all rooms impose their specific colourations on the speaker due to the frequencies hitting the walls. ceilings floor etc. and creating all kinds of undesirable effects. He contends that a narrow smooth well controlled dispersion pattern limits the sweet spot to a very small area but within that ‘sweet spot’ the room disappears from the equation.

Some other manufactures go completely the opposite direction and provide as wide and as flat a polar response as possible (omni type speakers). Most other speakers of course are forward firing speaker systems which have the midrange and tweeter dispersion as wide and smooth as possible in the forward plane or variations on this theme. Then there are the Dipoles which have a unique ‘figure 8’ dispersion pattern.

Thought it might be of interest to get your take on this and ask if you have had any experience with these different types of speakers in your personal systems?

James

Anonamemouse · « **Reply #1 on:** 28 Feb 2010, 04:00 pm »

first of all, the perfect loudspeaker system does not exist, and will never exist. nothing will be able to reproduce sound in the exact same way it originally happened. it will always be a poor copy of the original, no matter how many millions one spends.

with the above in mind it basically all comes down to personal preference.

i build loudspeakers myself (one has to have a hobby

) and have tried and tested various designs and concepts. i am a member of a dutch forum on building them, and as such heard many different loudspeakers. some with very narrow dispersion, some with very wide, most somewhere inbetween.
dipoles are in a league of their own, because they "rely" on reflection to happen.

to a certain i agree with mr sanders' thoughts. creating a loudspeaker that has a very narrow dispersion has the advantage that sound is very much directed to a particular point in the listening area, which causes a tiny sweet spot that has the most detail possible (unless one uses headphones). this is a good thing if one is willing and able to create a listening room set up to perfection, is single, and will never get married (or will only marry a deaf partner

). it will only sound great in the exact right spot, the rest of the room is of non importance when it comes to listening. to me it is kinda similar to listening with headphones on.

the extreme wide dispersion has the advantage that the reproduced sound sounds pretty good everywhere in the room, with a peak at the sweet spot. that peak at the sweet spot will not sound as excellent as with a narrow dispersing loudspeaker. in my opinion a wider dispersion pattern is more civil when it comes to house mates, plus it allows you to enjoy music in more than one spot in the room. i think it also gives more depth to whatever i am listening to.

a friend of mine built a set of dipoles, which definitely sound "different". because there is no cabinet (the units are simply mounted in the baffle with nothing but air behind them) sound comes from both sides. as a result the sound reflects on everything in the room, creating a very open atmosphere, with a large sweet spot. one needs to have very high efficiency units for an open baffle dipole loudspeaker, because there is no cabinet to build pressure in. detailing is very high though...

i have no experience with electrostats.

my current loudspeakers are somewhat of a combination of narrow and "midwide" dispersion. my setup is a close to 60 x 60 x 60 degree set up, but my listening room doubles as our living room, so i have to compromize (and avoid discussions with my girlfriend and our kids on sound related issues, although my son realizes the importance of high quality sound now too

). for my situation this works very well, once we move i will definitely also keep an eye on the acoustic possibilities in the new house. i would now want to end up in a place that sounds like a massive cave...

werd · « **Reply #2 on:** 28 Feb 2010, 11:52 pm »

One thing that never seems to get mentioned regarding the sweet spot is volume/loudness. Most room's sweet spot is not only dependent on speaker location but also volume/loudness that the soundstage is at its best.

In line with aforementioned reviewer above I like speakers that (or even speaker placement) that present a very narrow soundstage. This of course can be wrecked with too much listening volume applied. The room starts to suffer from too much a reflection or freq damp.

95Dyna · « **Reply #3 on:** 1 Mar 2010, 12:07 am »

My speakers have a front an rear firing super tweeter, 1.5" ribbon tweeter, 3.5" dipole midrange, 4.5" mid bass and 2 12" woofers. I guess that makes them schizophrenic in that they have a couple different dispersion pattern designs in the same speaker enclosure (59" H x 23" W and only 7" D). My sweet spot is moderately wide I would say. Things that are supposed to be stage center (like vocals) will stay there if I move a couple feet either way. How well other instruments stay put in that deviation depends alot on the recording I have found.

Bill

Raynald · « **Reply #4 on:** 3 Mar 2010, 01:28 am »

James, when I was selling your products I was lucky to have a wide selection of excellent but very different speakers to experiment with. At any one time I might have had most of these on hand:

Kef R107
Quad ESL-63
Thiel CS 3.5, CS5
PrAc Response Two
Meridian D600
Mirage M-1
PSB Stratus

Plus a bunch of other pretenders, but those were probably the most interesting.

I think Anonamemouse is right, all attempts will be imperfect and it depends what you value most. I would take it a bit further. Each designer takes a different approach. Depending on how good (and lucky?) he is, he will get more or less close to the goal of working with the way your ear and brain function to come up with a device that presents a convincing arguement that makes you think there is something happening in front of you that you know can't really be happening.

Each of us may have a particular inclination to prefer one type of design or another, but if someone comes up with a different design that is particularly
convincing we might go along with that one.

I can say that properly set up the Quad, Kef, ProAc and Mirage all gave very convincing performances but sounded nothing alike. Heck, the Carver Amazings could even put on quite a show depending on progam material, at least until the telephone gauge wiring inside started to smoke, the particle board mounts for the crossovers started to get charred and the hot melt glue holding the components on got hot and, you guessed it, melted! (To be fair, all of the above could be avoided by using Bob's own amps which would obligingly shut down long before any of that happened, at least early on in the speaker's career.)

The imaging area standout of the bunch for me was the ProAc Response Two. It had the uncanny, almost eerie ability to imagine way outside the standard sweet spot. You could set them up for great imaging when sitting between the speakers and then move to a spot almost directly in front of one of them and the image barely moved. I had a pair at home for quite a while and I remember often sitting quite close to one and not having any impression of sound coming from that speaker, everything was happening well beyond the plane of both of them. Absolutely remarkable. The speaker itself was very unremarkable, apart from the price for its size, and I am not really sure how it did what it did.

Compare any of the directional speakers to the Bi-Polar Mirage M series and things got interesting. The Ms were less precise, less holographic, a bit more vague. Probably all that sound bouncing around the room. Yet they created a very solid and convincing image. I would have to say that when I am at many live performances, when I close my eyes the precision with which I can locate performers in the room is closer to Mirage than ProAc.

No real point here, just some ramblings based on my experiences, hoping to bring something to the discussion.

And James, as you well know, at that time Floyd T. would say wide dispersion was best and he certainly knew more about speakers even back then than I will ever know!

James Tanner · « **Reply #5 on:** 3 Mar 2010, 01:13 pm »

^^^

Hi Raynald - ya I miss the good old stereo days

- life as an audiophile was so much simpler!

I am looking forward to trying the Rogers Electrostatics given their design goal of minimum dispersion. The KEF 207/2s I have appear to be just the opposite approach so I will give them a head to head comparison in my largest listening room. The Quad 2905's ( controlled dispersion concept) in the large room just do not have enough output to preassurize the room and sound very rolled off in the upper most octaves.

james

Housteau · « **Reply #6 on:** 3 Mar 2010, 02:38 pm »

I have some opinions on this. To start with I think we can mostly agree that the listening room is a major, if not the most major component in ones system. Roger Sanders apparently believes that particular component should be a neutral one, as many believe cables should be, just passing the information unaltered. However, others feel that certain components should be used to shape their sound, different tubes, cables, etc. to dial things in, as always trying to remain 100% neutral doesn't always work.

I fall into that second catagory with how I deal with my room, speaker listener interface. I believe in room treatments, but I also believe in using the room to work for me. It has good dimensions that are inches away from one of the 'ideal' ratios. Yet it still has many issues that adds its own character to my overall sound, but I like that. I have always favored dipoles in my room as they seem to interact with it in what I consider a positive way. I am not so sure the benchmark should be for prerecorded music to sound exactly the same in all systems and in every room. Most of it was created in an artificial environment and studio manipulated anyway. And as far as well recorded live performances go, this is how I look at that:

If musicians were playing live in my room it would sound a certain way due to the venue, just as it would sound different in somebody elses room. That does't make either of those performances wrong, just different from each other. To me the venue a performace is recorded in is a part of that performance, as is the room it is being played back in. We each can have a unique listening experience that is ours alone. I don't believe that automatically makes one of them wrong. If you go to a movie you can see the vision of the director, but read the book instead you can have your own. Very often these differences are qute small anyway and not so different from just moving seats and/or rows at a live venue. However, there are really terrible rooms out there and with those I agree that it would be best to either eliminate it, or get a new room.

As far as being able to reproduce the original event, this is my experience with that. This year and last I participated in the live vs recorded demos put on by VMPS at THE Show portion of the CES. This year we were at the Flamingo. My recordings there used purest tecniques of straight mic to recorder without compression, or limiting of any kind. Each song was recorded, then instantly played back to the audience to compare. Were the recordings identical to the live? No, they varied as the material varied, but some were pretty darn close and a lot closer than many said they would have thougt possible. It is important to note here that the less than perfect reproduction probably had a lot more to do with the microphones and positioning, rather than the speakers and playback chain. Also, recording and playing back within the same room allows the room acoustics to be added in twice, once during recording and another time during playback.

In my room I can feel the emotion of those performances. The tone, the soundstage, the focus, its all there and seemingly correct. Whatever my room is adding to the mix works as it does a good job of recreating the live events I made those different recordings in.

HsvHeelFan · « **Reply #7 on:** 3 Mar 2010, 09:32 pm »

Quote from: Housteau on 3 Mar 2010, 02:38 pm

I have some opinions on this. To start with I think we can mostly agree that the listening room is a major, if not the most major component in ones system.

<snip>

If musicians were playing live in my room it would sound a certain way due to the venue, just as it would sound different in somebody elses room. That does't make either of those performances wrong, just different from each other. To me the venue a performace is recorded in is a part of that performance, as is the room it is being played back in. We each can have a unique listening experience that is ours alone. I don't believe that automatically makes one of them wrong. If you go to a movie you can see the vision of the director, but read the book instead you can have your own. Very often these differences are qute small anyway and not so different from just moving seats and/or rows at a live venue. However, there are really terrible rooms out there and with those I agree that it would be best to either eliminate it, or get a new room.

<snip>

Exactly and well stated!

I like a wide and deep soundstage since I feel that music should be enjoyed by everyone that can hear it.

It's not easy to put 2 or more people in the "sweet spot" if the sweet spot is a 3 ft by 3 ft square.

By the way, most musicians immediately have an opinion on where they play. There are great concert halls and there are really, really poor sounding concert halls.

The Orchestra I'm in upgraded our concert hall with a Wenger Diva Orchestra shell. Expensive, but definitely worth it. Think of it as a very large "room" treatment.

HsvHeelFan

turkey · « **Reply #8 on:** 4 Mar 2010, 08:51 pm »

I tried omni speakers recently (the Mirage Omnipolar technology). I've also tried Ohm speakers with the Walsh radiator. I've heard other omni speakers over the years too, but haven't spent much time with any of them.

I have found that omni speakers don't image very well, and there always seems to be a blurring of detail.

I feel that the power response in the room is very important, but you also want to avoid early reflections, and that's pretty much impossible with an omni design.

I don't think a very narrow dispersion is the way to go, particularly when there's no control of directivity, as is true of most panel speakers.

Napalm · « **Reply #9 on:** 19 Mar 2010, 03:32 pm »

Hi James,

Some 5 years ago I spent many afternoons at Kennedy Hi-Fi in Markham checking omnipolar vs. front firing technology.

At that time they were Energy/Mirage dealers, and I had the pleasure to listen to Mirage OMD-28, OMD-15, Energy Veritas 2.3i and PMC OB1 in the same room (I think it was their best one), all powered by Bryston gear.

As a result of those auditions I ended up with having two separate systems: an omnipolar in the living room for HT and a front-firing one in the family room for stereo. (yes folks I don't have a TV in the family room - and that was on purpose).

The omnipolar works wonderful with HT surround setups - the sound from all the speakers blends perfectly in a continuous enveloping sound. You won't be able to tell where the speakers are located no matter how hard you try.

OTOH when used for stereo they fail at imaging and top end reproduction. They had some kind of smear in the spatial position of instruments/sounds. The front-firing speakers were extremely precise in this respect, you could feel exactly where each sound was located, with pinpoint accuracy.

Hope this helps.

BTW I just checked Bryston's website and I don't see Kennedy in the list of authorized dealers, what happened?

Nap.

James Tanner · « **Reply #10 on:** 19 Mar 2010, 03:50 pm »

We are revamping our website so things may be a little screwed up over the next week or so.

james

brentavery · « **Reply #11 on:** 10 Apr 2011, 08:12 pm »

Quote from: Napalm on 19 Mar 2010, 03:32 pm

Hi James,

Some 5 years ago I spent many afternoons at Kennedy Hi-Fi in Markham checking omnipolar vs. front firing technology.

At that time they were Energy/Mirage dealers, and I had the pleasure to listen to Mirage OMD-28, OMD-15, Energy Veritas 2.3i and PMC OB1 in the same room (I think it was their best one), all powered by Bryston gear.

As a result of those auditions I ended up with having two separate systems: an omnipolar in the living room for HT and a front-firing one in the family room for stereo. (yes folks I don't have a TV in the family room - and that was on purpose).

The omnipolar works wonderful with HT surround setups - the sound from all the speakers blends perfectly in a continuous enveloping sound. You won't be able to tell where the speakers are located no matter how hard you try.

OTOH when used for stereo they fail at imaging and top end reproduction. They had some kind of smear in the spatial position of instruments/sounds. The front-firing speakers were extremely precise in this respect, you could feel exactly where each sound was located, with pinpoint accuracy.

Hope this helps.

BTW I just checked Bryston's website and I don't see Kennedy in the list of authorized dealers, what happened?

Nap.

It really depends on what you are looking for. I have a pair of the OMD -28s. I like how real they sound. The soundstage is huge and very deep. If definitely lacks the laser focus of my friends B&W 801s, but to me they sound very natural.
They really do disappear once the music starts and the musicians seen to naturally spread out in space, both across and in depth.
Most front radiators I hear have people too clumped in the centre of the stage, between the speakers.
Rarely hear people outside of the speakers, but the OMDs spread about 3 feet beyond the width of the speakers
(some great 1st and 2nd order info)

Again the room is very important, more so with really dispersive speakers, took months for me to find the correct speaker locations.
The best part is the the sweet spot in the room is very large.
They sound great even if you're not sitting 2/3 back, centred in the room.

Compared to front radiators, they do trade some of the nuance and accuracy for space.
(eg. can't hear fingers on the strings as clearly, but you do hear it)
But to my ear, the space is amazing and sounds much more like live.

My Deutsche Grammophon recording of Tocca & Fuge is a relevation - organ pipes exploding around the room.
The decay and echo is marvelous - like I'm sitting in the church.
IMO worth the trade.

I use them for both (2 chan and HT), by they really live for Hi-Fi.

PRELUDE · « **Reply #12 on:** 18 Apr 2011, 12:38 am »

Hi James,

It was about 4 years ago that I was in SSI show in Montreal and came across this this B&O speaker called BEOLAB 5 www.bang-olufsen.com B&O is more about style then HI-FI but I think this speaker was an innovation then just another speaker. It is a 4 way active system that could do things that I did not hear in any other rooms. They have this speaker in B&O store in Toronto near young and bloor and I do like the sound. The only down side, that I do not like it powered.I like to have freedom to choose the power amp that I like but it will worth the listen.

harbies · « **Reply #13 on:** 18 Apr 2011, 08:44 am »

Interesting concept ie. narrow dispersion. Seems to make music listening a solitary and lonely exercise. The picture of a spot marked “X” with a single armchair on which rises shiny stainless steel skull shaped adjustable head restraints (with protruding butterfly nuts and bolts) come to mind.

Would it be more practical (and simple) to treat the room properly? Or sit closer to the speakers with the volume lower? or get the right speakers for the room ie. not putting a grand piano in a 5x3 meter room for example.

Anonamemouse · « **Reply #14 on:** 18 Apr 2011, 11:00 am »

Quote from: brentavery on 10 Apr 2011, 08:12 pm

My Deutsche Grammophon recording of Tocca & Fuge is a relevation - organ pipes exploding around the room.
The decay and echo is marvelous - like I'm sitting in the church.

Which one is that?

Housteau · « **Reply #15 on:** 18 Apr 2011, 01:27 pm »

Quote from: harbies on 18 Apr 2011, 08:44 am

Interesting concept ie. narrow dispersion. Seems to make music listening a solitary and lonely exercise. The picture of a spot marked “X” with a single armchair on which rises shiny stainless steel skull shaped adjustable head restraints (with protruding butterfly nuts and bolts) come to mind.

Would it be more practical (and simple) to treat the room properly? Or sit closer to the speakers with the volume lower? or get the right speakers for the room ie. not putting a grand piano in a 5x3 meter room for example.

Even in a well treated room of proper dimensions with properly sized speakers and a two channel system set up to perfection, there will be only one very small spot within that space where ALL the magic will happen. If you are using a speaker, or has a set-up that is able to create a much larger sweet spot with a uniform sound for multiple listeners, then without a doubt that uniform sound is far from the very best possible. There will be large compromises elsewhere. That is the nature and science of two channel listening and it all comes down to what we, the designers of our own listening spaces value the most.

Anonamemouse · « **Reply #16 on:** 18 Apr 2011, 03:18 pm »

Quote from: Housteau on 18 Apr 2011, 01:27 pm

Even in a well treated room of proper dimensions with properly sized speakers and a two channel system set up to perfection, there will be only one very small spot within that space where ALL the magic will happen. If you are using a speaker, or has a set-up that is able to create a much larger sweet spot with a uniform sound for multiple listeners, then without a doubt that uniform sound is far from the very best possible. There will be large compromises elsewhere. That is the nature and science of two channel listening and it all comes down to what we, the designers of our own listening spaces value the most.

I agree. Even in professional recording studios there is only a small spot in which everything is perfect...
If you want the live experience, the real thing is the only option.

James Tanner · « **Reply #17 on:** 18 Apr 2011, 04:10 pm »

The laws of physics dictate that you must be equidistant from both speakers for your brain to have the accurate phase information needed to generate a 3-D image.

james

werd · « **Reply #18 on:** 18 Apr 2011, 04:12 pm »

Quote from: James Tanner on 18 Apr 2011, 04:10 pm

The laws of physics dictate that you must be equidistant from both speakers for your brain to have the accurate phase information needed to generate a 3-D image.

james

At the balance control set in the middle

Mag · « **Reply #19 on:** 18 Apr 2011, 04:35 pm »

That's the beauty of using a MC AV/receiver pre-amp. One can change the timing delays, speaker distances to create a soundstage that you like, near field, far field, forward, laid back, whatever. You can then change it around or back, no reason to get bored with the same old sound day in and out. So what if the volume knob craps out, with all the sound parameter changes you won't even notice that tiny bit of distortion.