How I see the speaker system design problem

[soundminded]

I used to believe everything most audiophiles believe. There was a time when I kept shopping and comparing speakers looking for the one that would sound just right, just like live music. I never found it. I was certainly impressed by those two live vs recorded demos I heard using AR3s back in the 60s but in the showrooms and in people's houses, with regular recordings they didn't sound so real anymore. Nevertheless I had high hopes for AR9. I played with equalizing them for years but they never sounded right to me. I went to a few trade shows and saw what other people were doing. They had bipolar panel speakers, bipolar dynamic speakers, pulled their speakers away from the walls, and one manufacturer whose speaker I admired very much, Snell had a model which used an indirect firing tweeter in their AIIIi a speaker system which impressed me greatly. So I began experimenting adding one pair, two pairs, and finally 3 pairs of indirect tweeters. It took me several years of thinking about it to understand what this does.

Imagine a globe lamp which has to illuminate a room with white light. But unlike a normal lamp, it generates light the way a color television picture tube does with low frequency red phosphors, middle frequency green phosphors, and high frequency blue phosphors. When they are properly balanced we perceive the light as white even though there are no white phosphors in a color TV picture tube. Now imagine that the lamp has its red phosphors spread uniformly all over, its green phosphors somewhat less uniformly more towards the front and its blue phosphors all on the front clustered in one spot mostly directly in front of you. You could balance the colors to be white in one spot or another but the entire globe can never be white and if the color where the blue is concentrated is white and the walls are painted white, the room will have a reddish green cast since that is the predominant color reflected off the walls. Of course the solution is to add more blue phosphors around the rest of the globe. Now if the walls were painted reddish, the light directed at them would still be red even if the light emitted towards the walls were white. The solution is to make that light bluer than white so that the reflected light would appear white. So a pulsating sphere loudspeaker if it could be built would not necessarily be the ideal speaker for a real room.

I have experimented with three different speaker system, AR9, Bose 901, and KLH model 6 adding indirect firing tweeters to all of them and carefully re-equalizing them. It is a slow painstaking job but when it's done, they can be made to sound just about right to me and remarkably similar to each other. The Bose 901 was especially difficult because of the necessity to biamplify them on account of the equalizer, and because of their direct/reflecting principle. Was it worth the effort? Yes for me it's now the only way to fly.

[dynaco_dan]

Hi soundminded ( sorry I don't know your first name )

You certainly are having fun at least searching for perfection.

I have had one opportunity to hear AR-9's at one of my frinds house.

Unfortunately he only usually tri-amped his regular speakers with 3 Crown DC-300A's, so I will have to say his amplification was ok for the AR-9's.

They sounded real nice to me but his room was not perfect, or his cables to his speakers or his un-filtered AC power to his sound room.

In other words, his systems aren't perfect.

My aren't either, that's for sure.

When I had AR-4X's back in about '67, we use to listen to FM late at night with the lights out.

Oh, listen to that, doesn't it sound real!

We kept doing this all of the time.

The Vancouver Symphony offered free public demostrations at a local Brentwood Mall in Burnaby BC in the center corridor.

Glass, concrete, tiles, open walkways, not quite your typical living room, that's for sure.

The Symphony played a number of pieces, trying to gather supporters for their regular paid Symphonies.

One point stands out after all these years, you notice it takes a while for me to get to the point, Heh?

The triangle, I believe, as I don't play any instruments, stood out from all the music and I remember commenting how loud and clear it was then.

Now most of you may have gone to Symphony Halls and know what I am saying, but in a mall no less.

The triangle stood way out, even though it is a small and almost insignificant sound compared to a kettle drum.

Soundminded, you have obtained that small, but important highend and dispersion that I think is usually missing from most hifi speakers on their own.

Thank you for a direction to go on and equipment needed to get there.

Have a great night.

>I used to believe everything most audiophiles believe. There

>was a time when I kept shopping and comparing speakers looking

>for the one that would sound just right, just like live music.

> I never found it. I was certainly impressed by those two

>live vs recorded demos I heard using AR3s back in the 60s but

>in the showrooms and in people's houses, with regular

>recordings they didn't sound so real anymore. Nevertheless I

>had high hopes for AR9. I played with equalizing them for

>years but they never sounded right to me. I went to a few

>trade shows and saw what other people were doing. They had

>bipolar panel speakers, bipolar dynamic speakers, pulled their

>speakers away from the walls, and one manufacturer whose

>speaker I admired very much, Snell had a model which used an

>indirect firing tweeter in their AIIIi a speaker system which

>impressed me greatly. So I began experimenting adding one

>pair, two pairs, and finally 3 pairs of indirect tweeters. It

>took me several years of thinking about it to understand what

>this does.

>

>Imagine a globe lamp which has to illuminate a room with white

>light. But unlike a normal lamp, it generates light the way a

>color television picture tube does with low frequency red

>phosphors, middle frequency green phosphors, and high

>frequency blue phosphors. When they are properly balanced we

>perceive the light as white even though there are no white

>phosphors in a color TV picture tube. Now imagine that the

>lamp has its red phosphors spread uniformly all over, its

>green phosphors somewhat less uniformly more towards the front

>and its blue phosphors all on the front clustered in one spot

>mostly directly in front of you. You could balance the colors

>to be white in one spot or another but the entire globe can

>never be white and if the color where the blue is concentrated

>is white and the walls are painted white, the room will have a

>reddish green cast since that is the predominant color

>reflected off the walls. Of course the solution is to add

>more blue phosphors around the rest of the globe. Now if the

>walls were painted reddish, the light directed at them would

>still be red even if the light emitted towards the walls were

>white. The solution is to make that light bluer than white so

>that the reflected light would appear white. So a pulsating

>sphere loudspeaker if it could be built would not necessarily

>be the ideal speaker for a real room.

>

>I have experimented with three different speaker system, AR9,

>Bose 901, and KLH model 6 adding indirect firing tweeters to

>all of them and carefully re-equalizing them. It is a slow

>painstaking job but when it's done, they can be made to sound

>just about right to me and remarkably similar to each other.

>The Bose 901 was especially difficult because of the necessity

>to biamplify them on account of the equalizer, and because of

>their direct/reflecting principle. Was it worth the effort?

>Yes for me it's now the only way to fly.

[soundminded]

"They sounded real nice to me but his room was not perfect, or his cables to his speakers or his un-filtered AC power to his sound room.

In other words, his systems aren't perfect."

Mine are not even close to "perfect" in the audiophile sense either although as an engineer I feel they are perfectly fine and do not need upgrading (except for more power for my Bose 901s.) Of all of these so called shortcomings, the only one which gives me a problem are that some of my incandescent light dimmers can cause hum and noise. A good power conditioner or a UPS should take care of that. I've certainly spent more millions on them (some huge) for industrial installations than I can count.

It was many years ago that I realized also after listening to lots of live symphony orchestras and soloists in concert halls (and other places) that perfecting every element in the conventional paradyme audiophiles used and continue to use for sound reproduction will never duplicate that sound if for no other reason than the reverberation can't be recorded and their playback systems are incapable of reproducing it properly even if it were. They will never come even close. But the way they are going about it they won't even duplicate the sound of actual musical insturments as they would be heard in their home which is about as much as I feel I can reasonably expect. Fortunately for me I've got a few instruments including a beautiful restored 1927 Steinway grand in the same room as my AR9s to use as a live reference. BTW, the tweeters I use are small polypropylene models made by Audax, Dayton and similar costing about $6 to $8 each. No single tweeter no matter how good can duplicate what an array does IMO. I've had a lot of fun experimenting with loudspeaker systems in my own way and with modeling and trying to duplicate various reverberant sound fields. Now there's a toy that is a tweaker's dream come true, a lifetime of twiddling. I've been at it on and off for over 31 years.

[dynaco_dan]

Hi again

One only has to read back reviews of speakers on the Stereophile web-site, to see the difficulties manufacturers have.

Take one or two speakers that were reviewed, and I am doing this not from their actual review either.

For example and not necessarily applicable to these speakers or any particular brand or model.

I used these two, as, you would think they would be faultless maybe at their premium price level.

The Dynaudio top speaker about $60,000.00 or Wilson Whamm (?) $70,000.00, read the reviews from bass to treble each compliment and criticism if there were any.

Now if you owned these, do you own the same cables from source to pre-amp to amplifier to speakers as in the review?

Do you also own the pre-amp, amplifier, cd-player, very special turntable, arm and cartridge combination, etc, etc?

How about the room used in the review along with the sound absorbers?

How about the altitude where you live and the humidity as well.

Even if the manufacturers rep arrives and they setup the speakers with their perfect location, quite often a reviewer has to re-position them.

There is always some other speaker systems that is compared to throughout the review.

I don't mean that they are being nasty, but each reviewer has their own reference system or systems before each review is done.

They often comment on how this one has revealed a hidden soloist or the individual voices of a choir are distinct and not as forward or receded as another reference system.

They often refer to a specific instruments inner detail being superior on one reference and not so clear on another at some specific frequency.

I don't think I've read any review, in any publication, that the reviewer thought that any particular speaker system was perfect.

Ok, maybe, J. Gordon Holt's Dynaco A-25's review way back is an exception.

I wanted to show you that there is no perfect speaker system yet.

If you read each review you can see that, this woofer combined in a single enclosure, with that upper woofer, combined with this lower mid-range, combined with that mid-range, combined with this lower tweeter, and then add that super tweeter.

Heavens did I miss out on the crossovers?

If all of the top end manufacturers got together we would have the perfect single enclosure speaker system.

That is until a new and improved model driver came out the day after we declare our speaker system perfect, Heh?

Soundminded, you have very close to your perfection for less than $100.00, you sure are lucky.

Maybe a new model tweeter will come out tomorrow but still at less than $10.00 each.

You have it made.

You also probably have groceries in your fridge as well.

[soundminded]

"You also probably have groceries in your fridge as well."

:-) You are really funny Vern. As it turns out, I live with a packrat. And she has had a thing about groceries among other things all of her life. In my house there is a 25 cu ft, a 24 cu ft, an 18 cu ft and a small refrigerator and a 25 cu ft (approx) freezer as well. And all are packed to the brim. There is enough food between the refrigerators, freezer, and pantries to feed us and the dogs for at least six months. I just turned down another 24 cu ft refrigerator for free from a friend who is remodeling her kitchen...she wants all stainless steel appliances (although for the life of me I cannot understand this current fashion, why would anyone want their kitchen to look like an institutional or industrial kitchen is beyond me but that's fashion.)

I've had a lot of fun playing with audio equipment over the years. When I went to school, I heard a theory from some distributior/repair service that once an amplifier had reached a certain degree of accuracy, any improvement would be inaudible. I still belive that although I'm not even sure what that means anymore. Believe it or not, I still buy amplifiers on specifications alone, that is unless I see a bargain I can't resist.

The changes I've made to speakers have made the sound of the treble qualitiatively different. It is very clear without being harsh. It still has to be equalized to be properly balanced. Once this change is made, anything is possible. Without it, my experience tells me nothing works. When you get these systems perfectly adjusted, you just know it just like when you adjust the color on a TV set and you get it just right. Everything seems to fall into place. Interestingly, speakers like AR9 can be adjusted to provide overwhelming bass without the system ever seeming bass heavy. And for me that's a welcome change too.

[dynaco_dan]

Hi again

>"You also probably have groceries in your fridge as well."

>:-) You are really funny Vern. As it turns out, I live with a

>packrat.

Actually this was the quote from a doctors wife that I met several years ago.

Her husband went to a fellows home to buy a piece of Audio Research stereo equipment, all this fellow had was a stereo, bed, fridge and a chair.

There wasn't much for groceries in his fridge, apparently, priorities I guess.

The listening session of the AR-9's was not very long or with any familiar pieces, I can't give a better comment about them.

Just the fact I met someone with AR speakers, nevermind AR-9's was a thrill for me.

I would have loved to have had my cd collection with me and all the time in the world to really give them a run.

I always enjoy your writings.

And she has had a thing about groceries among other

>things all of her life. In my house there is a 25 cu ft, a 24

>cu ft, an 18 cu ft and a small refrigerator and a 25 cu ft

>(approx) freezer as well. And all are packed to the brim.

>There is enough food between the refrigerators, freezer, and

>pantries to feed us and the dogs for at least six months. I

>just turned down another 24 cu ft refrigerator for free from a

>friend who is remodeling her kitchen...she wants all stainless

>steel appliances (although for the life of me I cannot

>understand this current fashion, why would anyone want their

>kitchen to look like an institutional or industrial kitchen is

>beyond me but that's fashion.)

>

>I've had a lot of fun playing with audio equipment over the

>years. When I went to school, I heard a theory from some

>distributior/repair service that once an amplifier had reached

>a certain degree of accuracy, any improvement would be

>inaudible. I still belive that although I'm not even sure

>what that means anymore. Believe it or not, I still buy

>amplifiers on specifications alone, that is unless I see a

>bargain I can't resist.

>

>The changes I've made to speakers have made the sound of the

>treble qualitiatively different. It is very clear without

>being harsh. It still has to be equalized to be properly

>balanced. Once this change is made, anything is possible.

>Without it, my experience tells me nothing works. When you

>get these systems perfectly adjusted, you just know it just

>like when you adjust the color on a TV set and you get it just

>right. Everything seems to fall into place. Interestingly,

>speakers like AR9 can be adjusted to provide overwhelming bass

>without the system ever seeming bass heavy. And for me that's

>a welcome change too.

[Guest mjasilli]

I would simply like to add my two cents to the discussion that is going on here. I think another way to put "the problem with speaker design" is that there are simply too many variables to take into account for any company to design the "perfect speaker". By the time you deal with the size of a room, the density of walls and the placement of all the furniture and other stuff in the room, you start to realize that finding a place to put your speakers and still have a room that you like and want to be in to listen to you stereo is a gargantuan task. Add to that the fact that pretty much everyone has a different oppinion on what makes for a good sound -- just getting into the tube vs. solid state amplification debate is like entering the 6th circle of Dante's hell -- and you wind up in a situation where nothing is going to satisfy everyone. This may in fact be a good thing, it keeps people researching and developing new equipment, and keeps the debates raging over audio equipment. In fact, that is part of what I love about audio equipment, it gives me a chance to express myself through my projetcs and efforts toward certain sound qualities.

In fact, it is precisely the fact that I do not want to settle for what other people have come up with that I have moved into DIY audio. I was tired of hearing that I needed an ideal room . . . basically that I needed to work my life and my living space around my audio equipment if I wanted "really good sound". The demands of audiophile sound always bothered me -- it sounds to me like the drivel of snobs looking to exclude people from a world of enjoyment that they for some reason feel the need to close off instead of opening to as many people as possible. Yet, we are trapped in their snobby discourse and developments, because they are the people who make the equipment -- unless that is, you learn to do this stuff yourself to your specifications based on your room and your preferences. I love the fact that Audiominded uses $10 dollar tweeters in his projects, but puts the time in to model the acoustics he is trying to achieve to produce apparently fantastic results. Because that's what its all about, isn't it, satisfying your craving for a dose a acoustabliss.