Ohm decided to try to finish them, and bring the product to market. Ttelja, are these the new series 3 you are talking about? |
Ohm is still one of the classic lines Totaly agree and they are available now. But I did post this on a different thread....."From what I have read about audio and video, what I would like, is not available, at least not yet, and that would be 75" SED TV and a pr. of properly designed Walsh speakers." |
Sean has owned the Ohm F's and loves them. I own the Ohm 4.5 MX II and love them. But Sean has never owned the latest Ohm's and I have never owned the F's. So Sean nor I really knows which are better. Agreeing is not the same as experiencing. |
Personal taste is whats it all about. I upgraded from the OHM 4XO to the OHM 5 about a year ago and love them, they just sound right to me. They will play VERY loud with lots of power. I use a Sunfire amp. that produces 600 watts per. ch. at 8 ohms and 1200 watts per. ch. at 4 ohms. This kind of power realy gets a grip on these speakers. I used to use an amp. that produced 200 watts per. ch. at 8 ohms and 325 watts per. ch at 4 ohms; this amp. would clip at higher volume levels. These speakers do go into the 4 ohm area, so it's good to have the power there. |
Nanderson and Sean...There is a Blue Circle amp. review i think would be of interst to you guys. This review shows that it takes ample power to turn the Ohm speaker into truly high-end speakers. Just Google "Soundstage Blue Circle Audio BC8" |
I have the Walsh 4.5 Mk II and find them so very easy to live with. There is no divorce in sight, I am in love.
I heard the F's some 40 years ago and did not have the coin in which to buy.
What I have never come across is an A/B listening test between the F's and the 5 Mk II, but I would put my money on the 5 Mk II as coming out on top. |
I also think it's ugly; the older models look good to with that trapezoid cabinet. |
Sean, I purchased my first pr. of OHM WALSH on Nov.3 1987, the 4-XO's. A Technical White Paper came with those speakers to explain too the purchaser how they operate and here is what it says in part....
This cone is fabricated of special materials which have a super-sonic velocity of sound propagation. By engineering the cone angle and propagation velocity properly, a coherent, cylindrical sound field is synthesized in the air around the cone; the listener, in fact, receives simultaneous sound.
As described previously, the apex of the cone is initially dent, and a sound-wave originating at the apex moves into the air at 1100 feet per second. Similarly, every point on the cone contributes its output at exactly the right time for ALL the wavelets to coherently merge into a cylinder, as shown in Figure 3. Wherever the listener sits, all the sound produced by one pulse reaches the ear at the same instant. There is no "time-smear" or "time-delay distortion". END QUOTE
That is a description of a Walsh driver; the angle of the cone is just different from the F's angle because the material used to make the cone is different. The speed in witch sound travels in materials is dependent on what kind of material is being used and the cone angle has to be adjusted accordingly. This is why the angle of the cone in the newer Walsh drivers is different from the F's cones.
Just because the newer Walsh drivers are not mounted on a sealed cabinet does not change the fact that the driver itself is operating as described above.
What Eldartford said:...That there is a mechanical crossover at the point where the two dissimilar materials meat, is indeed a crossover. |
Sean, The term "super sonic" literally means faster then the speed of sound in "air". Sound travels faster in solids then it can in air. Therefore the sound wave traveling down the cone material of a Walsh driver, is at "super sonic" speeds. This is a scientific fact. How much faster the wave travels down the cone depends on the material being used to form the cone and the speed determines the angle of the cone. The correct angel lines up all the waves generated in the air to form a single coherent sound source, with no time-smear or time-delay distortion.
Sound travels at different speeds in different materials such as steel, plastic, water, air, etc. No, it does not create a sonic boom because there is nothing traveling in the air itself at "super sonic" speeds, the wave is traveling down the material. This is how the F's work and all speakers that work on Walsh's principal. |
That post didn't look like a joke, so I did a little research too find out just how fast sound does travel in some of these materials and here is a little of what I found...>> In general, sound travels fastest through solids, slightly less fast through
liquids, and slower through gases.
This is because the particles (atoms or molecules) in a solid are touching
each other and rather fixed together. That is why a solid is "solid." Since
the particles are bonded together, a sound wave moving one, immediately
transfers the motion the one touching it. A sound wave hitting one, is
almost immediately transferred to a neighbor.
In a liquid, the particles are touching each other, but they are not fastened
to each other quite so strongly as they are in a solid. Some of sound's
energy is wasted pushing the particles around because they can slide past
each other. Some of sound's energy is wasted that way and that is why it
moves slower.
In a gas, the molecules are rather far apart. For sound to travel through a
gas, the molecules must move quite a distance before they collide with other
molecules. Sound energy cannot move as quickly when the molecules are not in
contact with each other. Here is another from a different site...>> In air at room temperature, sound travels at about 340 metres per second. In water, sound travels about four times as fast as it does in air, while in steel, the speed of sound is about fifteen times as great as in air. Here is one I found interesting,..Why do we sound like Donald Duck when we talk with helium...>> We talk like Donald Duck because sound travels faster through helium and, in effect, shrinks our heads.
When we speak, the sound speeds from voice box to lips. Since sound travels faster in helium, the sound reaches our lips sooner with helium than air. Its as if the path were shorter. The faster sound speed raises the resonant frequency of our vocal tracts. We, sort of, become Oz Munchkins with high squeaky voices.
Every pipe, from our vocal tracts to an empty Coke bottle, has a resonant frequency. Blow air across a bottle. The deep sound we hear is the bottles natural frequency in air. Fill the bottle with helium and blow across the top. Now, sound travels faster and the tone sounds higher. The resonant frequency of a tube depends on the length of the tube and the speed of sound through it. The faster the sound speed, the higher the frequency. Well anyways, I bought my first pr. of Ohm speakers from a big box store called ABC Wharehouse purely on what I was hearing out of them, and at that time I did not know what was going on under that can, just liked what I was hearing. Some 15 years latter, I started hearing something that I should not be hearing out of one of them, so I opened it up and found the surround tore and replaced it with a new one. I left the can free so I could slip it on or off any time I wanted to. "And yes, I always wondered what they would sound like with the can off." So, many times I would listen for a different in sound between the can off and on, and I could 'not' here any difference. The driver is not a mass projection driver; this is very apparent when it is looked at. They look hand built, and I believe they are. This tells me that this driver is NOT ordinary. No; I can not know what is going with this driver by looking at it. The cone is some sort of plastic, the magnets look massive, and the can is essential to protect some kind of (what I believe to be) some kind of sound absorbing material that is placed is certain places. The driver is not pretty, in fact, I think it is ugly, but it can't be seen anyways. I don't have the XO's anymore because I upgraded too the Walsh 5 Mk-2 drivers and mounted the on the original trapezoid cabinets. I do not know what the new divers looks like with the can removed. Now Ohm does have models that are box speakers, and I would bet that the drivers in them are production speakers, (not hand built). Sean, I have a question for you...Do the F drivers have a spider? I think that they would have to. |
Sorry: I posted the wrong link for 'two cans and a string'.
Here's the right one.
http://science.howstuffworks.com/question410.htm |
Unsound, reading this over, I could not find any signs of mechanical cross-overs.
http://www.german-physiks.com/NewFiles/WhiteBook.html |
Sean, I appreciate you sharing your knowledge, but there is something I don't understand after reading this quote from the German-Physiks files. The transmission line type has commonly employed a steep, straight-sided cone and a fairly conventional voice coil and magnet assembly. But where it differs from an ordinary mass loaded cone is that the diaphragm is securely anchored at its mouth and flexed by the motions of the voice coil rather than pushed to and fro. Sound propagation is normal to the slope of the cone rather than parallel to the path of the voice coil in the gap as is the case with a mass loaded cone. The diaphragm is securely anchored at its mouth. Wouldn't this mean that there is no spider employed ? And is sounds as though there is no surround employed ether. What I am trying to get at is; the F's do employ a spider and a surround, and I am wondering if the sound emanating from the F's is a mix of conventional speaker sound and transmission line sound. What do you think? Am I missing something? |
Jamscience, thanks for the patent info. and picture.
One thing I would like to say, is that the cans are not diffusion cans, they are as transparent too sound as grill cloth is. |
Jamscience, now we can argue over...'Is John actually marketing what he had patented .
When I said, "the cans are not diffusion cans", what I meant is that the meshed cans are not employed to create a the widely dispersed sound that they are know for. That widely dispersed sound is still there with the cans removed.
And what I mean by acoustically transparent is...If I were to put a singing canary in one of those meshed cans, I personally, would not be able to distinguish a difference in sound of the canary, (Is the singing canary in or out of the can?). Similarly, when I am inside the house listening to birds that are outside through an open window, I cannot distinguish the difference in sound weather there is a screen on that window or not.
I did eventually affix the cans back over the drivers for shipping purposes, they would be more vulnerable to damage without them. The foam that lines the interior of the cans is there (I believe) to help keep out dust and potato chip crumbs etc. The foam is thin, in the area of 1/32" or 1/16".
I know what the Mk-2 driver looks like, because I can see it without removing the can with the use of an LED flashlight, and the picture Jamscience posted of the FRS-11 is reminiscent of the Mk-2 in looks. The sound absorbing material that is so unattractive is no longer visible; the driver is no longer ugly. The tweeter and it's mounting DO look quite different from the picture of the FRS-11. The tweeter and it's mounting is now much more attractive.
I do not know which earlier models are ugly, except for the one's I had, which were the 4XO's. |
To complicate this subject even further, IF I understand this link
http://home.swipnet.se/~w-61372/artiklar/article3.htm
correctly. DDD's generate (what I would call) surface wave ON the cone, like waves on the surface of water and the Ohm F's generate (what I would call) compression waves IN the cone, like two cans and a string. (If you don't know what I mean by two cans and a string, here is a link.
http://home.swipnet.se/~w-61372/artiklar/article3.htm
The DDD's and the F's generate sound in two distinctly different ways. I believe the DDD's do not have a spider or a surround for that very reason. What do you guys think? |
Sean, I examine it, question it, go into it and find out on my own whether what I read makes sense to me and so far, it does not.
I agree with you on...how could reasonable SPL's be achieved without suspension. But on the other hand "with suspension", what is the cause of increased SPL's? You said yourself that the wave alone could not achieve the necessary SPL's. So I wonder if the sound being emitted from the cone is a mix of wave transmission line and conventional piston action? I do not know what else could be responsible for the higher SPL's.
I looked at the Ohm 5 Mk-2 again and there is no longer any back damping. It is omnidirectional now except for the tweeter. The can measures 9 3/4" high and the bottom 1/3 of the can is omeni, 360 degrees.
Sean, how far from the back wall did you position your F's? |
What is a pure Walsh driver supposed to be? This is what I think is should be. Please correct me if what I say here is wrong.
A pure Walsh would emit sound 'only' by means of transmission line, and if the driver had suspension, that would introduce a sound that is not transmission line sound, but that of a conventional speaker. So the sound being emitted from a Walsh with suspension would not be pure transmission line sound, but rather a mix of the two.
A Walsh driver generates waves down the cone material, whatever that material my be. And from what i understand, this can be done one of two ways.
One way is to generate waves by bending the cone material itself and the waves are moving at supersonic speeds and different wave frequencies will have somewhat different supersonic speeds. From what i have read, this is how the DDD works. This method requires a very thin and ridged material.
The second way, is to generate a compression wave, in which the waves are not on the surface, because there is no bending involved, the cone material itself is being compressed, (not bent). Compression waves are also super sonic.
In ether of these methods, the proper angle of the cone will depend on the speed of the wave on/in the material being used. The greater the speed, the steeper the proper angle will be. The F's use metal and sound travels much faster in metal then in plastic, therefor the steeper angle is required if a metal matteral is used for cone material. Now, if the wrong angle is used, the waves generated in the air will not line up to form a single coherent sound source, and this will create time-smear or time-delay.
The use of suspension may or may not be necessary (i don't know), but if it must be used, i do not see how it could be pure transmission line.
This is what i understand as how a Walsh driver works. Am I wrong?
From what i understand, the DDD employed the first method and the F's the second method. |
Sean, I wonder if a Walsh drive (which does have suspension) would also emitting sound by means of piston action like a conventional driver does, and if it indeed does, that would boost the SLP. You see, I don't know, but would like to know. But I don't see how it could not.
And a steep cone like the F has (which looks to be about 60 degrees or so), would be less efficient at this then a cone at 35 degrees would be.
An I making myself clear? |
Three or four years ago I auditioned the Ohm Walsh 200 MkII's with their at-home trial and found them missing the special qualities I remembered. They were a bit on the heavy sounding side and lacked the sense of space I was after. That was a pity as I really wanted them to be as magical as the F's from many years before. I never owned the F's and heard them so very long ago; but what you said here confirms what i do remember and how the F's sounded compared with MkII's. I think the F's cone is the coolest looking speaker there is. |
Just to add my experience to this conversation.
I have the Walsh 5's series 2 and drive them with a Carver amp. that outputs 600 watts per. ch. into 8 ohms and 1200 into 4 ohms. I have on occasion play them loud enough (in a 16' X 24' X 9' room) that i cannot hear my own voice when taking normally. I heard that the series 3 are easier to drive but don't know if that is a fact or not. |
