REVEALED: Celestion's F12M -150 "Triple Cone" for amp modellers

[ArtieToo]

I installed them in my 2x12 Marshall it is probably one of the best-sounding cabinets I own right now. Here is a review I wrote on them.

Great review. Now I really got to get this thing installed. So . . . the Wheel House = the JS? Interesting.

[Securb]

Software engineers are a good example of this. They are not ACTUALLY engineers, there is no school or credential that gives them an engineering degree.

I work with software engineers every day. They have degrees in Software Engineering some have their Masters Degrees of Doctorates. You have lost all credibility.

http://catalog.mit.edu/degree-charts/computer-science-engineering-course-6-3/

[Securb]

Great review. Now I really got to get this thing installed. So . . . the Wheel House = the JS? Interesting.

It is very cool because the JC combo is open back. My cab is closed back and has more punch, so when I use it for metal of thrash it really barks. The chorus with the Wheelhouse speakers sounds studio clean if that makes sense.

[ArtieToo]

The chorus with the Wheelhouse speakers sounds studio clean if that makes sense.

Yup. It does. I'm also going to be installing this into a closed back cab. So that's good news.

[Ewizard]

The JM Donut may not reflect the audio back to the speaker, that is not as much of the point I was making. It was that the path of flow that the HF audio makes through the foam mesh, has many different path lengths. The path length in the center vs the path length to HF that exits at the periphery of the Foam donut are drastically different. The tangent between those two exit points and your ear is what will cause the destructive interference. Now imagine all the other potential paths that the audio can travel and exit through that foam donut at! They are all different path lengths, meaning all of them will shift the length of time relative to one another as it exits the foam. That is the cold hard physics of it. Cannot be changed and 100% exist.

Now, that does not mean that it doesn't do what it says it will do. It also does not mean that it will sound bad doing it. I am only pointing out that it does something that is considered, objectively, to be a bad thing. And if Jay or anyone else tries to tell you it doesn't, they are lying to you or trying to sell you something.

Not having actually read any of Jay's stuff about his donut, I can only see one way to spin it. Correct me if I am wrong. My guess is that his supporting thesis is that the HF energy travels through the foam and exits out of thousands of the different " cells " in the foam. Each one is so close that the destructive interference between any nearby cell is minimal to nonexistent. He is trying to use line array theory for this. The path length between each adjacent exit point is so close that it effectively couples and the time variance from the center to the periphery causes a coherent dispersion of HF audio. That is my best guess as to what he said to support his product. Am I way off base, or close enough?

I would say that at distance, this idea holds up fine. But in the near field, perhaps not so much. When you place a microphone in front of the foam mesh, you now have a very small diaphragm that is only able to pick up a fraction of the cells. Each cell has a different path length and they will propagate over time differently on the microphone's diaphragm. I.E. the microphone's close proximity to a few cells and its ability to hear other cells further away make destructive interference at the mic more possible. This is of course an oversimplification of the potential. The math is where we really learn.

Sound effectively couples when the two sources' acoustic centers are within 1/4 of a wavelength of each other. Beyond that, they start to destructively interfere. A 1khz sine wave has a wavelength of about 1'. So for effective coupling to occur, the two acoustic centers ( the cells in this case ) must be within 3" of each other. No problem in this case if the foam is acoustically transparent to frequencies above 1khz. If not, there will be minimal destructive interference at 1khz, there already is with just the speaker cone alone.

Most guitar speakers are good up to about 5khz though. So what's the math on that look like? A 5khz wavelength is about 2.7" (let's just say 2.5" to keep it easy ). This means any two cells that are beyond about .625" ( 5/8ths of an inch ) apart, will start creating destructive interference. A microphone can hear much more than 5/8ths of an inch worth of a speaker cone. There will be a fair amount of destructive interference the microphone can actually pick up.

Going even higher in frequency, perhaps to the limit of interest for guitarists, a 10khz frequency has a wavelength of about 1", this means that any cell that is beyond 1/4" from one another will create destructive interference. There is no doubt that there is comb filtering going on at this frequency. But why does this not make as much of a difference when you're further away?

The angle of incident is the key. If speaker A is 1' directly to your left and speaker B is 1' directly to your right, as long as you stand still you won't hear anything weird. But as you shift your head from side to side ( changing the relative distance between Speaker A and Speaker B to your head ), you will start to hear the wooshing and weird audible anomalies of that point in space. Now imagine that you stay directly in between the two speakers, but walk away 25'. As long as you keep your head perfectly between them you will hear them as if it was normal, but as you shift your head left to right, you will notice that the change in the sound you hear is different, it will only affect the higher frequencies. This is because your acute angle to the speakers means less drastic of a change in tangent between them. Now as you move further away to say 50'. You may notice that you can't move your head far enough left or right to hear any major change in sound at all. This is because you are now so far away that the tangent between the two speakers when you move your head is minimal or essentially too small to cause a problem.

So going back to what I was saying about placing a mic in front of a speaker and coming to a quick result. If I don't catch that there is some sort of device in use behind the speaker grill, and I place the mic like I normally would, and I don't like what I hear, I need to go back and move the mic. If again I don't catch that there is a device in use at that point, I will move the mic to acquire an expected result. If it's too bright I will move the mic further out into the cone, and if it is too dark I will move it closer to the dust cap. Now you can see what I mean by expected outcomes vs shooting in the dark. If the device does something that creates unexpected results, I am shooting in the dark as to how to fix my problem.

So again, I'm not saying the JM Donut is crap, I'm not saying that it doesn't work, only that it does something, and it may or may not have negative outcomes. If what the mic hears and what you as a player hears are two totally different things, as a live sound Technician ( to keep it real around here ) I have to try and capture what you are hearing. I am not trying to trudge my own ground with regard to your guitar tone. I do use a bit of artistic judgment and flare, but it is usually only to make things work as a whole, obviously, the guitar can't be so boomy and bassy that it walks all over the bass guitar. If your guitar tone is that full and big, I have to do some amount of neutering to make things work.

All that stuff above is what I have rolling through my head when I am placing a mic. Do I pull the mic back off the grill a little to change the angle of incident, do I move the mic left or right, do I move both back and to the left or right? I'm doing real-time math in my head as I place the mic and then come back to move it. The hope is that if I do move it, I made the right assessment and came close enough to solve my problem.

Why can't I spend more time? I have a drummer, to deal with many of the same things for. I have percussion too maybe? Then two guitarists. etc. etc. If I'm a monitor engineer, I have a lot to do in a very short period of time during a festival. You only get one, maybe two opportunities to move any one mic and get a good result. This is why I am not a fan of these devices, because they do not exhibit expected outcomes. They solve one problem and create another; usually.

[misterwhizzy]

I can only speak for myself, but when I see a post like the above, I see a giant block of text and skip it. When I want to read technical analysis, and I often do, I don’t read it on forums.

[Ewizard]

Which is why I said the short version about 10 posts ago. And if you read any of that, you would see why wrote a stinking book. So then when I give you the TLDR version I get the TLDR response. Can't win.

Freaking colleges man, They will find a way to milk every dollar out of you and lead you down this path of believing things that aren't real. BTW, the link you ( Securb ) posted was a link to a computer sciences program. As mentioned before a computer science degree is/can be an engineering degree. However, as I will note below, a BS in science is what most Software Engineering and IT degrees are tied to. NOT a computer science degree. You can have both, you can have a master's in both. A computer science degree is another step above credential-wise to a basic science degree. Science degrees usually have an " IN " placed after it, describing what the specific field of science was studied. A BS of Science in Animal Behavior for example. Or a BS of Science in Computational Linguistics.

Again you have to look closely at what the degree they hand you is actually of. The " Software Engineering " degrees that I find seem to all be tied to a basic science degree. A degree in science is NOT an engineering-grade degree. When you read the differences of what a degree in software engineering vs computer sciences offer, the latter provides you with much broader employment horizons. The software " engineer " part is often swapped with developer, development, or programming. Again while the course may say software engineering, it's what's on the degree that matters. It probably says Bachelors degree of Science in Information Technology or software engineering. The degree you are getting is a science degree. It is NOT the same as a Computer sciences/engineering degree. It is NOT the same as an Electrical Engineering degree. It is NOT the same as a Mechanical engineering degree. If you get a degree of science in software engineering and go to a Board of Engineers to get certified, you won't be, because the board has repeatedly denied the skill or trade of being a Professional Engineering certification. They were very close to making it a certifiable trade in 2012, but as of 2018, they are not accepting testing for certifications in most of the developed world, Texas is the only state I have read of that has a form of accreditation in the US. There is even a Wiki page dedicated to the " Software Engineering Professionalism " movement. : https://en.wikipedia.org/wiki/Softwa...rofessionalism

To technically call yourself an Engineer, you must be licensed/certified by the Board of Engineering. Shall we argue some more over it?

So a software engineer is pretty much like a sound engineer, which are both like a chiropractor. Not a doctor, not an actual engineer.

[Aceman]

Dude - can you just write a book and if we care to, we'll buy it....

[Ewizard]

Orrrrrrr......... You could engage in meaningful conversation and contribute. I'm not a post count collector. I present information, facts, data, experience, and even on some occasions, attitude. I'm sometimes wrong both in my answers or responses and even with my attitude. This topic has gotten completely derailed, and part of the reason, I feel, is that I am just getting picked on by the clique. The useless, non-contributing comments seem to keep coming. So sorry, I wrote anything at all. Heaven forbid I provide information, on a forum, designed to share information.

[ArtieToo]

It is very cool because the JC combo is open back. My cab is closed back and has more punch, so when I use it for metal of thrash it really barks.

I wonder how long it would take for the 150 watt Wheel House to get broken in? I only play at "bedroom" volume. Could take years before it sounds "right."

I'm usually not a big believer in "break-in", but I do recognize it for electrical-to-mechanical and mechanical-to-electrical suspensions. Such as speakers and phono cartridges.

[LesStrat]

Never mind.

[Securb]

I wonder how long it would take for the 150 watt Wheel House to get broken in? I only play at "bedroom" volume. Could take years before it sounds "right." I'm usually not a big believer in "break-in", but I do recognize it for electrical-to-mechanical and mechanical-to-electrical suspensions. Such as speakers and phono cartridges.

When I put in the Wheelhouse 150s we were house shopping so I was living in an extended stay hotel. I had to play at below bedroom volumes for 10-months and the speakers sounded great. When I joined the band the speakers got pushed with the Marshall for a few months when I had trouble with my 4x12 and shined. Not sure if they are "broken in" but they sound better and better at all volumes. I have the cab back at the house now with the JC again and it is simply a monster.

Think about how polar opposite a Marshall JCM200 and a Roland JC120 are, the speakers sound phenomenal with both amps.

[ArtieToo]

When I put in the Wheelhouse 150s we were house shopping so I was living in an extended stay hotel. I had to play at below bedroom volumes for 10-months and the speakers sounded great. When I joined the band the speakers got pushed with the Marshall for a few months when I had trouble with my 4x12 and shined. Not sure if they are "broken in" but they sound better and better at all volumes. I have the cab back at the house now with the JC again and it is simply a monster.

Think about how polar opposite a Marshall JCM200 and a Roland JC120 are, the speakers sound phenomenal with both amps.

That's good to know. I'm going to try to get this installed this coming week. It would be cool to have this in a 212 cab with the Celestion Tri-Cone, to compare them.