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In Reply to: RE: Looks to me like posted by seancuster71@gmail.com on March 23, 2025 at 16:06:28
from a company like ATC, Dutch & Dutch, JBL, Neumann, Genelec, etc. that has woofers on angled panels beside the others.
Follow Ups:
With the long wave lengths of a woofer in a 3 way it doesn't matter if they are mounted on angled panels. Indeed there are currently speakers with the woofers on the side(e.g. KEF Blades).
The angle though is probably there to minimize horizontal mid range diffraction which would occur with a right angle.
(The angle though is probably there to minimize horizontal mid-range diffraction which would occur with a right angle.)
The angled drivers on the KEF KM1 are bass drivers with a crossover point of 400 HZ mid-range is usually considered to start at 500 HZ. Speakers are round so sound waves radiate in all directions from a speaker, so diffraction happens in all directions not just horizontal and at all frequencies not just mid-range. And diffraction does not occur with right angles. Some people think diffraction is the same as reflection sound waves reflecting off a speaker baffle, but they are two very different things. Diffraction is the bending of sound waves around obstacles. And reflections are sound waves bouncing off a surface.
Darn and for 6 decades I've heard it called diffraction.
And you're right it occurs vertically too but on a well set up system the horizontal diffraction control is more important.
So, for 60 years you have known about diffraction so you understand diffraction that's great makes this post easy
Diffraction is what happens when sound waves emitted by a speaker encounter obstacles. So, a speaker's cone is round, and it moves, producing sound waves off the entire surface of the cone in all directions, not just horizontal or vertical just like I already said in a previous post. Just think of dropping a rock in water: the ripples spread out from the center in all directions. So, think of the speaker as the center and sound waves emitting outward from the speaker. And diffraction does the same exact thing no matter what direction it is traveling. So, to say diffraction in one direction is more important than diffraction in another direction is to not understand what diffraction is and how it works. Another byproduct of diffraction is baffle step. Baffle step can be stopped by flush mounting drivers, or if you're using DSP you can also account for baffle step when designing a passive crossover. You will also hear people talk about edge diffraction. This is why a lot of manufacturers round over cabinet edges.
I think you're getting diffraction confused with dispersion. When we look at dispersion it is actually opposite of what you say. Horizontal dispersion you don't want to control you want it as wide as possible this is good vertical dispersion is bad and if you can control vertical dispersion that's good.
That's why 99% of speaker horns/waveguides are rectangle and wider than they are tall. They are widening horizontal dispersion and controlling vertical dispersion. It's called speaker pattern control.
Speaker design is a fascinating subject if you ever want to learn more about speaker's and speaker terminology and design you should check out Vance Dickason loudspeaker cookbook 8th edition.
yes, so what, the horizontal problem has to do with the enclosure and the KM1 design will deal well with the horizontal diffraction which is also minimized by the narrow center md/tweeter panel which is a plus on small box speakers.
I think you may be barking up the wrong tree. Angling the woofer panels by 20 degrees or so has little to do with diffraction around the sides, but will affect the dispersion pattern, by possibly reducing lobing and uneven dispersion due to constructive and destructive interference between the woofers on either side of the cabinet. Whether or not KEF chose the angle scientifically through measurements, or just guessed, I wouldn't know. Or, as I wrote in an earlier post, it may just be for aesthetic purposes, to make the box look less boxy.On the other hand, the "Blade" series with woofers on the sides is a different animal. Although the woofers are smaller than in the KM1, they still cross at 350 Hz or higher, depending on the model. Using 1129 feet per second as the speed of sound, the wavelength at 350 Hz is about 3.22 feet. With a nominal woofer diameter of 9 inches and an effective radiating diameter of about 8 inches, it is likely that the dispersion pattern is "adequate", especially given that the forward-oriented midrange driver overlaps the upper end of the woofer frequency range. It would be interesting and useful to see a polar plot of the actual dispersion pattern.
I haven't heard any of these speakers, whether well set up or not, so I can't comment on their actual resulting sound. In any case, as you might know, what one person thinks sounds fine or great, another person doesn't like.
Just as a sort of add-on to the discussion, here is a page about diffraction, as applied via an opening in a wall. The same concept applies to baffle edge diffraction.
(Source: Olson, "Music, Physics and Engineering")
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We are inclusive and diverse, but dissent will not be tolerated.
Edits: 03/29/25
Woof woof!!
Oh boy!! Where do we start? This is a doozy!!! of a post.
Ok Inmate51 you say, "Angling the woofer panels by 20 degrees or so has little to do with diffraction around the sides, but will affect the dispersion pattern, by possibly reducing lobing" Ok what is lobing? Lobing is when two or more speakers emit the same frequency at a distance greater than a quarter wavelength of the sound. Ok how to minimize lobing as it pertains to the KEF KM1 speaker? Angling the sides like you say will not do anything to stop lobing. If you want to reduce lobing there are several things you can do. First place the woofers close together like the KM1 does. Speakers playing the same frequency spaced far apart create more lobing placing them closer together will reduce lobing. Second Using steep crossover slopes like the KM1 does. The KM1 is an active speaker with electronic crossovers that have a very steep 24 dB per octave slope greatly reducing lobing. Unlike shallower 12 dB and 18 dB textbook passive crossover slopes that are never textbook because they do not include the acoustical properties of the drivers, and all drivers are different that's why we measure. Third way to reduce lobing on the horizontal axis is to stack the drivers vertically which the KM1 does.
So, it seems KEF knows how to design speakers. They have the woofers close together and stacked vertically and have a steep 24 dB per octave slope electronic crossovers. Also, if we look at the KM1 from a designer's viewpoint we will understand why they angled the sides. Because it narrows the center baffle where the midrange and tweeter live and that will help minimize baffle interactions with the midrange and tweeter. Not to make the box look less boxy like you say, remember this was a speaker not intended for home audio, so they did not care about looks. Most of the time when talking about speakers the form is for function not looks. But in this case sacrifices firing the woofers off axis to narrow the baffle for the mids & highs.
Then you say (Using 1129 feet per second as the speed of sound, the wavelength at 350 Hz is about 3.22 feet. With a nominal woofer diameter of 9 inches and an effective radiating diameter of about 8 inches, it is likely that the dispersion pattern is "adequate") Wow this really makes no sense its pure gibberish. Ok please explain how determining the wavelength of a given frequency can tell you the dispersion pattern is adequate by adequate I guess you mean wide to give a good soundstage. There is only one way and one way only to determine a speaker's dispersion pattern and that is by measuring on axis then measuring 15,30,45,60 degrees off axis these are the measurements you must take to upload into software to produce a polar plot and a polar plot is the only thing that will show you a speakers dispersion pattern. You also said the woofers are a nominal 9" nominal means "in name only" so are the woofers 9" or are they 9.4" and KEF just rounds them off? You also said the 9" speaker has an effective radiating diameter of about 8". There is no such thing as a speaker having a 8" radiating diameter. The radiating surface of a speaker is measured in cm squared and it is only counting the cone not the surround. So a 8" diameter circle has about 322 cm squared or 50 square inches surface area. However, the average 8" speaker cone not including the surround has an average 211 cm squared or about 32 square inches radiating surface.
And the paper you pictured has the name Olsen. I wonder if that's Henry Olsen. Henry Olsen is an audio pioneer, a very important pioneer to say the least. He was the first person to measure diffraction I think in the mid to late 1930's and the first person to use a curved baffle also in the 1930's. And that picture you posted. You said " Just as a sort of add-on to the discussion, here is a page about diffraction, as applied via an opening in a wall. The same concept applies to baffle edge diffraction " Oh no that paper does not apply to baffle edge diffraction at all read what you posted carefully. Here is the actual definition of edge diffraction verbatim " A phenomenon where sound waves, upon encountering the edges of a speaker cabinet/baffle are scattered and readiated, creating secondary sound sources that interfere with the original sound waves. potentially key word potentially leading to coloration or blurring of the sound. So how does a paper on the concept of sound traveling through a hole in a wall relate to the concept of a speaker cabinets edge diffraction?
Extraordinary claims need extraordinary evidence and what can be asserted without evidence can be dismissed without evidence. However, I provided ample evidence to not only dismiss but debunk the preposterous claims you have asserted in this doozy of a post.
Everything in your post is wrong and all of it is covered in that book. You say you own the Vance Dickason loudspeaker cookbook so either you have not read it or you do not own a copy.
Olson, not "Olsen".Author of "Acoustical Engineering" and it's derivative work "Music, Physics and Engineering", as well as many professional papers.
I have no idea who Henry Olsen is.
*********
We are inclusive and diverse, but dissent will not be tolerated.
Edits: 03/30/25
The sides are angled for the mid ranges, not the woofers
See link below.
Also:
https://www.erinsaudiocorner.com/loudspeakers/kef_blade2_meta/
Thanks for that. Even though I have no, none, zero interest in buying their speakers, it's still an interesting read! Thanks.
*********
We are inclusive and diverse, but dissent will not be tolerated.
I bought 3 Blade 2 Metas for L/C/R and I love them, both before and after reading those references. See link below for more measurements (as well as my comments).
I hope you didn't misunderstand! I'm not poo-pooing the KEF speakers. It's just that I'm reasonably happy with the EV/Dynaudio DIY that I have, and expect to be even happier with the new speakers I've planned and will hopefully finish over the next few months.I'm glad that you are happy with your purchase! That's the goal.
As I wrote previously, I haven't heard them, so I have no idea how they sound.
:)
*********
We are inclusive and diverse, but dissent will not be tolerated.
Edits: 03/30/25
no one does that any more. Looks dated.
It's 4 decades old
I think I read somewhere that the crossover from the woofers is 400 Hz. If that is correct, it made sense to angle them. There's also the aesthetic aspect - angling parts of the front panel creates a more pleasing, less "big box" visual appearance.
*********
We are inclusive and diverse, but dissent will not be tolerated.
In 1982 when these speakers came out, they were talked about for many reasons and angled baffle for the bass drivers was not one of them. The fact Quad and KEF worked together to develop the speakers along with the fact the quad amps could push 1600 watts, and the speakers could hit 120dB were the main things people referenced when talking about these speakers.
Looking at them from a designer's point of view I can say I do not like the angled baffle. Bass is omni directional from 100 HZ down some say. I feel its 80 HZ and down. The KEF KM1 run the 4 bass drivers to 400 HZ so let's say under 100 HZ is omni directional so if the crossover point was 100 HZ that's fine but 400 HZ that is two octaves higher.
So, your fist 2 octaves of fundamental frequency's you're hearing off the driver's axis common sense says that's bad. But KEF obviously does not agree.
But to answer your question how many monitors use angled baffles who knows although not monitors Polk audio comes to mind so do (buy other sound equipment) aka Bose.
But I am sure with so many speaker manufacturers out there that there are more. It's a wacky world full of strange things
It's interesting that the KEF Blade speakers also cross from woofers to mid at 400 Hz and the woofers are on the side of the speaker 90 degrees from facing forward and the Blades are great speakers. The angling of the bass drivers is no problem if the system is designed for it.
I look at speakers from a designer's perspective. With that said WTF!! was KEF thinking.
It's really easy to laugh at a bad design so let's laugh at a $35,000 poorly designed KEF Blade. The Blade speaker's crossover points from the side firing bass drivers to the uni Q front facing driver is 450 HZ.
When we listen to our speakers we are listening to instruments and vocals. Instruments & vocals have a fundamental frequency and above the fundamental frequencies are overtones and harmonics. The fundamental frequency is the first harmonic so say 100 HZ is the fundamental frequency the 2nd harmonic is double the fundamental frequency 200 HZ and the 3rd order harmonic is triple 300 HZ.
The average vocal male & female when singing is 100 HZ to 400 HZ so the entire fundamental frequency range of the human voice singing is firing out the side of your speaker moving away from you while all the harmonics are coming out the front driver straight at you. Acoustic guitar has a fundamental range from 80 HZ to 1200 KHZ that's 4 octaves. 80 HZ to 160 HZ first octave 160 HZ to 320 HZ second octave 320 HZ to 640 HZ third octave and 640 HZ to 1280 HZ is the 4th octave. So, the blade is firing the first two octaves of the guitar out the side bass drivers and the last two octaves and all the harmonics out the front driver which is crazy considering the first two octaves is all your Rythm frequencies.
Also, if you look at the speaker and its design it will tell you why the woofers are side firing. The front of the speaker is to narrow and curved making it impossible to mount the bass drivers in the front of the speaker where they belong. The cabinet is curved to help with diffraction this sacrifice's playing the fundamental frequencies of 90 % of instruments out the side of the speaker away from your ear while the rest of the sound is coming straight at your ear's pure genius!!!
Ever wonder why 99% of speakers all the drivers are on the front baffle facing you. Or a panel speaker all fundamental frequencies & harmonics coming of the front panel facing you not dividing instruments frequencies and pointing them in different directions around your room.
Also could you imagine room placement problems with drivers firing into your walls which is something you do not want pure genius!!! all for just $35,000 dollars!!! Good news is for $35,000 they come with a free divorce lawyer.
The better option would be buy KEF Ls50 meta for $1000.00 a pair then buy two Bowers & Wilkins ASW608 8" subs for $1200.00 a pair. Now buy a good $200 calibrated microphone and download REW room EQ wizard put the microphone at ear level where you sit to listen and move your subs around in your room to get a flat bass response meanwhile your LS50 can be placed to give you the best imaging and they play from 47 HZ to 45 KHZ straight at your ears just like a normal speaker. Bass is omnidirectional from 80 HZ down and your subs can be cut off at 40 something hertz to match your LS50 and you're under $2500.00 for a system you can fine tune. And you won't get divorced for spending $2500,00 on speakers. And I bet the LS50 with subs will sound way better.
And while the side firing KEF Blades are bouncing sound off your walls back to your ears after traveling 15 to 20 feet around your room, that sound will meet your ears that are only 8 feet Infront of your KEF blade speaker late causing major phase issues pure genius!!! But if you can afford $35,000 for speakers you can buy a big field with nothing around for your side firing woofers to reflect off of!! And you can sit in the middle of a field divorced listening to your $35,000 KEF Blades way to go KEF great design pure genius!!!!! and wait I bet these speakers have been voted number one by people KEF paid to say they are number 1 and even funnier I bet people believe it.
The fact is and I hate to say this, and I would not say this if it was not true. Most all audiophiles know very very little about their hobby and it shows due to the fact manufacturers take full advantage of this fact sad but true.
An uninformed consumer is manufacturers dream. An uninformed consumer is a gullible consumer and manufacturers love it!!! and sadly rely on and take advantage of this fact.
But hey for $35,000 they might not be a total waste you can lay them on their side and the side firing woofers will now be aimed at your ceiling just like Dolby Atmos!!!
Funny KEF aka Kent Engineering and foundry has foundry in it name considering I bet know one at KEF knows what a foundry is, and the only metal casting associated with KEF is the Chinese factory that is casting their incredibly overrated little drivers.
Obviously you've never heard a set of blades properly set up.
I have at an audio expo back in February and I was not impressed at all have never been impressed by KEF. KEF makes low sensitivity drivers and low sensitivity drivers are known for being like a flat soda lifeless dull 100% not dynamic. And if low sensitivity was not enough, they are coaxial and in real life sound does not come to you from only one point, so any realism is lost.
It's important to remember the first coaxial speakers made were Altec Lansing 604's and they were not invented for sound quality they were invented to save space and be compact.
Coaxial speakers have to many problems.
The woofer is used as a waveguide on KEF speakers the woofer moves as the soundwaves from the tweeter move across its surface causing ripples inter module distortion. Not to mention were the tweeter meets the larger cone on KEF speakers the design causes diffraction artifacts that are noticeable at higher frequencies.
And the biggest problem and the most obvious or should be the most obvious there are three bands of frequency bass, mids, highs there is absolutely no substitute for each band having a dedicated driver specializing in its given frequency range. Coaxial will always lack in the bass due to the fact its designed more for the critical mid-range rather than bass.
What's funny is KEF coaxial suck compared to Tannoy coaxial. A Tannoy 15" gold will make KEF owners cry Altec Lansing 604's also are KEF killers the difference between a good coaxial and a KEF coaxial is night and day.
A good design stands the test of time Altec Lansing 604's are still being made by the same tooling that has always made them, and they are made by some ex Altec Lansing employees that bought the tooling decades ago. Tannoy 15" gold was made unchanged from 1967 to 2015 Altec 604 from the early 1940's until now still basically unchanged. The fact that KEF is on their 12th version of the uni q driver is hilarious 12 attempts and they still suck LMAO!!! And 5 years from now KEF will be on their 20th version and it will still suck.
Great plains audio/Altec Lansing still making the world's number one coaxial driver a driver that has not changed because it does not have to from 1942 till now 83 years and still making them that says it all.
The only thing that stands out about KEF is their marketing department the Uni Q driver came out in 1987 so in the last 37 year they have 12 versions each claiming to be better than the last. That is a new version every 3.08 years. Read about every version they supposedly keep fixing problems the previous version had but they keep saying they are improving things they say they already improved yet have to improve again and again.
so coaxes suck except that's not true for Altec's. And the main driver acts as a wave guide(I agree) for the tweeter but it's compromised by the main driver movement. Yet the KEF crosses at 400 Hz which minimizes movement. And the Altec is a woofer with larger movement(albeit reduced due to its large area).
Sorry once again your wrong. Altec's main driver I think you mean the cone acts as a waveguide not true the Altec have a horn and do not use the cone as a waveguide. Early Altec 604's used sectorial horns later versions used the manta ray a non-sectorial horn.
Now let's look at basic physics of speaker's cone larger cone speakers move less to produce sound than smaller cone. So, a Altec 604 has a very small xmas aka the amount of travel a cone can move measured in mm a little tiny 6.5" KEF cone has a much higher excursion or xmas or cone travel meaning while the large 604 cone is not even moving 2mm and producing bass the small 6.5" KEF cone would have to move 6 mm to 8 mm to produce good bass. So, throw that argument out the window.
And the KEF crosses over at 400 HZ not even in the ballpark not even in the same country as the ballpark. The tweeter used on the KEF coaxial could not be crossed that low a matter of fact no dome or ribbon tweeter will cross that low or nowhere near that low. The higher the quality tweeter the lower its crossover point the cheap little, tiny magnet tweeters on a KEF uniq driver probably crosses over well above 2000 KHZ
And a speaker cone moves more the lower the frequency goes so Altec 604's crossover at 1600 KHZ so if the 604 used the cone for the waveguide it would be moving less at the 1600 KHZ crossover point than the 400 HZ you claim the KEF crosses over at due to the fact a speaker's cone moves more at lower frequencies than at higher frequencies.
At what point will you stop guessing and actually fact check yourself before you post? correcting you is getting old already.
As far as Altec being better than KEF that is well known by even casual audiophiles. Altec 604 the world's first coaxial invented before the nuclear bomb or jet airplane is iconic speaker and is still being made today. Used in over 83% of recording studios over from the 1950's into the 1990's something KEF cannot claim since they only made one studio monitor the KM1 used in only one studio not 83% of studios worldwide like the world famous Altec 604.
Also, the 604 was chosen by pink Floyd and used in arguably the greatest sounding concert tour of all time Pink Floyds the wall.
I am not just a speaker designer I am an audiophile history buff I love history more than designing speakers guess I am just a nerd!!!
1968 Bose and Polk!
Hey, you asked a stupid question I gave you too incredibly stupid answers
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