Do we still need panel speakers in 2012

[Robh3606]

It took two attempts, the second one taking four years to successfully re-engineer it into a two way full range bi-amplified system. The system is specifically engineered for the spot it's in in a particular room. If it were moved it would have to be re-engineered all over again.

Hello Soundmind

How/why did you biamp them??

"Don Keele and Marshall Kay of Audio Artistry have changed the way that line arrays operate."

The Pro Version

http://www.jblpro.com/catalog/General/ProductFamily.aspx?FId=89&MId=2


http://www.jblpro.com/BackOffice/ProductAttachments/CBT Tech Note Vol 1 Number 35 091007.docx.pdf


Rob

 

[A.wayne]

Bose, JBL, AA, I guess we wont be needing panel speakers anymore huh .....

 

[FrantzM]

Someone built a pair for our club's biannual DIY loudspeaker contest. I remember that it sounded pretty good. Very coherent for a near-field line source. very little comb filtering. You need to sit pretty close to them, and they are quite big. Not sure I understand how it works or why they curve them like that.... but I didn't look deeply into the design.

They were designed by some serious people:

"Don Keele and Marshall Kay of Audio Artistry have changed the way that line arrays operate."

As some may remember Kay worked with Linkwitz at AA and Keele was a reviewer (and developed many speaker measurements) for Audio magazine.

http://www.xlrtechs.com/dbkeele.com/

http://www.audioartistry.com/papers_keele.htm

http://dagogo.com/View-Article.asp?hArticle=938

Thanks Garry, Myles and Kach

I think they deserve a good audition. I haven't heard any Constant Directivity (CD) yet but the idea makes sense. If we look at the directivity of most any speakers, we will see it varies greatly with frequency. From omni in the bass to a small beam in the highs. This is often accomplish with horn with the added advantage of the higher efficiency, this dos it with line source. The idea is not too far from many line source, their departure is in the constant directivity ... I do believe that one of the attraction about the MBL 101 is its constant directivity: It radiates sound at all frequencies through a sphere... I observed the same with an old design that we had at home for a while an Empire Speaker, I can't remember the model, maybe Grenadier, I was a kid less than 10 years old, that was also omni. Later in my audiophile life I heard the Shahinian Obelisk and they tended to do the same thing, the spooky impression of having stereo almost anywhere you sat in the room ... I didn't like the omni designs then nor do I like them now. The MBL 101 however does certain thins extremely well though and surpass what I heard in the former omni. Not my cup of tea however.
Speaker directivity plays a great role in wht we perceive and how they sound in a room. I would surmise that CD speakers tend to sound the same in most rooms. I believe we will see more of CD speakers in the future as we learn more about sound reproduction

Bose, JBL, AA, I guess we wont be needing panel speakers anymore huh .....

We audiophiles tend to look askance at brands that have (or retain) DIY in their DNA, we tend to forget the brands we now celebrate so much, Wilson, Magico, Rockport, Pass, etc came from a DIY mentality.. Wilson in particular, I used to read him back when he was a TAS reviewer (DAW) built his speakers for the purpose of monitoring his recordings .. The rest is history ... Several, today famous High End companies and brands likely started in a garage ...
I don't take Bose seriously in High End speakers (whatever that truly means, finish and cabinetry help a lot in what we perceive as such) but do not think for a second that they as a company are not capable. Their sound reinforcement speakers are held in high esteem by those who depend on sound for their livelihood, same with JBL and I have heard some JBL speakers I found very good .. As for Audio Artistry their designs have been well seen by many and the reviews from the High End magazines have been good to excellent ... Anyone who doesn't take Siegfried Linkwitz seriously needs a refresher (or primer) in speakers and crossover So let's keep an open mind

 

[kach22i]

http://www.selahaudio.com/id73.html

Nice link, beautiful selections of wood, and they seem reasonably priced.

Soundminded, I'm a visual person and without an example, a sketch or other graphic I feel as though I'm just guessing at what you mean.

However, and it's just my opinion and my bias, any conventional dynamic speaker array (vert. + horiz.) large enough to be "a wall of sound" will also act as a wall. That is to say it will give away it's location based on reflections off of it's front baffle. I'm not exactly sure why this would not also be true of large panel speakers now that I think of it, other than that surface is busy making music.

 

[microstrip]

(...) So let's keep an open mind

It is the only possible advice. More than with any other type of equipment, in loudspeaker design, one man's meat is another man poison. Speaker designers have to deal with two aspects with wide variance - the room interface and the listener preferences. It is not possible to please all of us with a single design concept.

 

[kach22i]

http://dagogo.com/View-Article.asp?hArticle=938

That last link is the best and only write up of the CBT36 speaker I've seen. Thanks, a good find.

Some of the best things happen at audio shows when you peer into a room with an unfamiliar name on the door, in this case a company named Audio Artistry. I was familiar with Parts Express, supplier to the DIY community but could not come up with a mental construct of a product by Audio Artistry. When I entered I beheld the CBT36, a “Constant Beamwidth Transducer” developed by Don Keele based on unclassified military underwater sound research. Holy Sonar, Batman! I will be direct; this was the most fascinating exhibit of the show, and perhaps my favorite in terms of overall satisfaction.

What is so interesting about the CBT36? It’s made of inexpensive materials such as a thin, MDF cabinet, has a slew of low cost drivers in ridiculously large numbers ( each tower has eighteen 3.5” full range and seventy-two ¾” tweeters, crossed over at 1kHz), and is designed with a radically unorthodox dispersion pattern due to the backward curvature of its cabinet. This, however, was no slouch system, as iTunes was being sent via Media Monkey software to a Benchmark DAC-HDR ($1,895), which in turn fed the DEQX HDP-Express Peamplifier/Processor ($1,950). Amplification was from a pair of Jeff Rowland’s Model 625 Stereo Amplifiers ($13.5K each). Interconnects and speaker cables were supplied by Cardas.

Listening to the CBT36, I thought immediately of speakers like the Pipedreams and Scaenas. In a unique fashion the arc-array puts the listener in the middle of a gigantic soundstage not just horizontally but vertically. The definition was exemplary, akin to an electrostatic speaker. I would have liked more mid-bass presence and a smidgen off of the treble’s intensity, but all in all there was acceptable integration with the pair of huge Parts Express RS1202K subwoofers wielding dual 12” oppositional drivers (list $1,099). In a word the experience was thrilling!

Thrifty as the CBT36 system is (the tower is bolted to the base with external metal plates) it conveys music vastly, with an enormous acoustic envelope typical of larger panel speakers. The CBT kit from Parts Express is $1,980 but needs the DEQX system to operate as a crossover, either the introductory HDP-Express or the HDP at $3,995, which includes room processing. It’s not, however, a $2K speaker; with subwoofers and DEQX one is looking at a kit system which must be assembled and costs between $6-8K excluding the demand for four channels of amplification to separately drive the individual bass/treble Left and Right arrays. Is it the cheapest speaker system I’ve heard at a show? No, not by a long shot, but it is one of the most memorable in the under $10K category. Audio Artistry plans to offer for $8.5K a version with internal passive crossovers, thus negating the need for the DEQX and two additional channels of amplification.

.......... an Empire Speaker, I can't remember the model, maybe Grenadier

I looked those up, very interesting. An old Ad below, might not be "work safe", different times.

http://sarahspy.com/post/311504293/vintage-empire-grenadier-speakers-advertisement

 

[Soundminded]

Hello Soundmind

How/why did you biamp them??





The Pro Version

http://www.jblpro.com/catalog/General/ProductFamily.aspx?FId=89&MId=2


http://www.jblpro.com/BackOffice/ProductAttachments/CBT Tech Note Vol 1 Number 35 091007.docx.pdf


Rob

The tweeters were biamped for several reasons. First of all, I didn't want the Bose equalizer signal in the tweeter circuit. If that had happened then a much higher order high pass filter would have been required to keep the amplifier from blowing them up with its bass signal. As it was, it was practical to use a receiver with an equalizer of its own to correct what I saw as the deficiencies of the Bose equalizer/speaker system. I've written extenisvely about this experimental system project elsewhere, on Classic Speaker Pages for example. In my 14 x 14 Sun room with a cathedral ceiling that extends from about 8 to 12 feet at its peak, original Bose 901 has a strong broad upper bass resonance of about 8 db centered around 500 hz that had to be removed (e/e magazine reported theirs as 7 db centered at 250 hz) but the deep bass was not nearly loud enough. Bose pushed the system resonance above 180 hz deliberately because he said that is where phase shift associated with resonance becomes inaudible. Below that he has a boost of 6 db per octave but the acoustic suspension design falls off at 12 db per octave very lineraly. In my room the bass crosses the 1 khz loudness point at about 95 hz. The bass actually requires an additional 6 db per octave making bass boost at 30 hz from about 26 to 30 db or more (further adjustment is required for each recording.) That means that to achieve the same loudness 1 watt would produce at 1 khz, at 30khz requires from about 600 to 1000 watts. The system is only rated to handle 270 watts so it would take about 3 of these systems or more to achieve the same loudness as AR9 (which also required a bass boost in a room about twice the size.) The point is that unless the strong bass output is kept out of the tweeters, they'll blow up. The additonal amplifier allows much easier adjustment of the tweeters independently of the mid woofers. Had the system use only one amplifier a separate low pass crossover network would have been required for the bose drivers which have their own treble peak which may be due to the equalizer itself. IMO the Bose drivers cannot reproduce the top octave of sound. So the Bose system has three fatal frequency response errors, no high treble, no audible deep bass, and an upper bass lower midrange peak. Small wonder audiophiles hate them. The design goal is that both the direct and reflected FR are flat when they reach the listener. Therefore the FR of the indirect tweeters is boosted to compensate for the frequency dependent absorption of the walls. This way the reflected sound remains reasonably flat too.

How do they sound now? Very different from what Bose's factory turned out. Their intended goal is to reproduce the sound of single and small groups of acoustic instruments as they would be heard in that room. A piano, string quartet, Dixieland jazz band, jazz trio, singer. They cannot reproduce the sound of a symphony orchestra or any other instruments as they would be heard in a concert hall just as no other 2 channel sound system can't either. The other experimental sound system I described elsewhere recently that received so many comments and questions is designed for that purpose. The funny thing about it though is that the two systems have in common that they are designed around the same set of mathematical equations describing sound fields. They are just solved for two different cases. One day I expect to consolidate them into a single sound system.

I could probably build a better speaker meeting the design criteria for this type of sound system than modified Bose 901 but not anywhere near the price. It would require far more complexity, and I'm not sure it would sound better. The reason I brought this up here is because due to the fact that most of Bose 901's sound is re-radiated over a very large area and reaches the listener from many angles it has much in common with panel speakers that do exacty the same.

 

[Soundminded]

Nice link, beautiful selections of wood, and they seem reasonably priced.

Soundminded, I'm a visual person and without an example, a sketch or other graphic I feel as though I'm just guessing at what you mean.

However, and it's just my opinion and my bias, any conventional dynamic speaker array (vert. + horiz.) large enough to be "a wall of sound" will also act as a wall. That is to say it will give away it's location based on reflections off of it's front baffle. I'm not exactly sure why this would not also be true of large panel speakers now that I think of it, other than that surface is busy making music.

This is a very complex question that goes to the heart of how we hear direction and what assumptions the stereophonic sound principle has made. The ability to quickly and accurately determine the direction of the source of sound is one of the key evolutionary assets in the ability of higher animals to survive in the wild (including the wild of city traffic.) Studying the reason for the failure of binaural sound, I've come to the conclusion that the usual explanation is either incomplete or wrong. Sounds having a very narrow angle of arrival at your ears are easy to detect. The slightest turn of your head causes sound to arrive sooner in one ear and later in the other ear. This is how you know not just the angle it's coming from but if the sound is in front of you or behind you. That tells you which direction to go to run away from it if it's a threat or towards it if it's prey. The stereophonic principle assumes that your brain will interpolate the relative loudness of the first arriving sounds from two sources and conclude they are a single source somewhere between the actual sources. Sound arriving over a broad range of angles IMO can improve this trick but only if there is sufficient high frequency dispersion. The abiltiy to detect direction is most sensitive at higher frequencies. Narrow angle HF propagation even with panel speakers such as from a vertical array of ribbon tweeters does not meet this criteria.

 

[A.wayne]

Thanks Garry, Myles and Kach

I think they deserve a good audition. I haven't heard any Constant Directivity (CD) yet but the idea makes sense. If we look at the directivity of most any speakers, we will see it varies greatly with frequency. From omni in the bass to a small beam in the highs. This is often accomplish with horn with the added advantage of the higher efficiency, this dos it with line source. The idea is not too far from many line source, their departure is in the constant directivity ... I do believe that one of the attraction about the MBL 101 is its constant directivity: It radiates sound at all frequencies through a sphere... I observed the same with an old design that we had at home for a while an Empire Speaker, I can't remember the model, maybe Grenadier, I was a kid less than 10 years old, that was also omni. Later in my audiophile life I heard the Shahinian Obelisk and they tended to do the same thing, the spooky impression of having stereo almost anywhere you sat in the room ... I didn't like the omni designs then nor do I like them now. The MBL 101 however does certain thins extremely well though and surpass what I heard in the former omni. Not my cup of tea however.
Speaker directivity plays a great role in wht we perceive and how they sound in a room. I would surmise that CD speakers tend to sound the same in most rooms. I believe we will see more of CD speakers in the future as we learn more about sound reproduction





We audiophiles tend to look askance at brands that have (or retain) DIY in their DNA, we tend to forget the brands we now celebrate so much, Wilson, Magico, Rockport, Pass, etc came from a DIY mentality.. Wilson in particular, I used to read him back when he was a TAS reviewer (DAW) built his speakers for the purpose of monitoring his recordings .. The rest is history ... Several, today famous High End companies and brands likely started in a garage ...
I don't take Bose seriously in High End speakers (whatever that truly means, finish and cabinetry help a lot in what we perceive as such) but do not think for a second that they as a company are not capable. Their sound reinforcement speakers are held in high esteem by those who depend on sound for their livelihood, same with JBL and I have heard some JBL speakers I found very good .. As for Audio Artistry their designs have been well seen by many and the reviews from the High End magazines have been good to excellent ... Anyone who doesn't take Siegfried Linkwitz seriously needs a refresher (or primer) in speakers and crossover So let's keep an open mind

Frantz,

When was the last time you has some good white rum, maybe that (seasons greetings) special egg nog, you seem a bit tense man

So do we still need panel speakers, or is their a Bose in your future ........

 

[A.wayne]

It is the only possible advice. More than with any other type of equipment, in loudspeaker design, one man's meat is another man poison. Speaker designers have to deal with two aspects with wide variance - the room interface and the listener preferences. It is not possible to please all of us with a single design concept.

Bingo ,

You win the egg Nog .....


Anyway interesting things happen when stuff is placed into the real world and no friendly press is in arms reach...

http://www.diyaudio.com/forums/multi-way/177403-linkwitz-orions-beaten-behringer-what.html

The orion has issues most are visable without even taking a listen and I know the man pretty well and take nothing or no one for granted in this business and yes Bose is a very serious Co and could do it , yes quite possible , but theres a reason why they haven't , very apparent reason ...

 

[FrantzM]

Someone built a pair for our club's biannual DIY loudspeaker contest. I remember that it sounded pretty good. Very coherent for a near-field line source. very little comb filtering. You need to sit pretty close to them, and they are quite big. Not sure I understand how it works or why they curve them like that.... but I didn't look deeply into the design.

Frantz,

When was the last time you has some good white rum, maybe that (seasons greetings) special egg nog, you seem a bit tense man

So do we still need panel speakers, or is their a Bose in your future ........

I don't drink and am not tense the least .. Very interested though in the discussions ...
may be in Miami next week (depends ) promise (if not next week, later this year ) to bring you some Haitian Rum, likely the best in the Universe ... It is strong ... though .. after a few sips you may find yourself finding the Bose Wave Radio all you need for music reproduction

 

[A.wayne]

You have to beat the good appleton over proof I'm already on ...

I don't drink and am not tense the least .. Very interested though in the discussions ...
may be in Miami next week (depends ) promise (if not next week, later this year ) to bring you some Haitian Rum, likely the best in the Universe ... It is strong ... though .. after a few sips you may find yourself finding the Bose Wave Radio all you need for music reproduction

 

[Soundminded]

Bingo ,

You win the egg Nog .....


Anyway interesting things happen when stuff is placed into the real world and no friendly press is in arms reach...

http://www.diyaudio.com/forums/multi-way/177403-linkwitz-orions-beaten-behringer-what.html

The orion has issues most are visable without even taking a listen and I know the man pretty well and take nothing or no one for granted in this business and yes Bose is a very serious Co and could do it , yes quite possible , but theres a reason why they haven't , very apparent reason ...

"but theres a reason why they haven't , very apparent reason ..."

Of course there is. They are in business for one purpose only, to make money. If they don't see any profit in it, why do it? They're very successful at making money. This alone is enough to inspire intense jealousy. They've written the niche high end audio market off. They see where the real money is, in the mass market. If I were in their shoes I'd do exactly the same.

 

[A.wayne]

Less not forget the good Beveridge .......

http://www.bevaudio.com/products.html