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Multi-Way Conventional loudspeakers with crossovers

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Old 24th August 2015, 01:10 PM   #13311
marco_gea is offline marco_gea  Italy
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Quote:
Originally Posted by POOH View Post
Of all the JBL 15's I have the JBL 2226 is the the last one I'd use in my system and is the last one I would use to declare ceramic magnets sound bad. It's really a good example of engineering a driver to fill a large area at high levels without burning the coils. Not so good for delicate hifi reproduction.

There are bad examples of Neo, ceramic and alnico drivers out there. There are good examples of all of them too. Throw away your broad brush and you will have much more to chose from to beat your cermaic magnet "Ariel."
Yes, I agree - it seems as if we posted our responses at the same time (see my previous message).

M.
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Old 24th August 2015, 02:08 PM   #13312
boldname is offline boldname
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Originally Posted by marco_gea View Post
I believe most of those sound differences that you mention are mainly due to other factors, such as mechanical damping: Rms/Mms ~ Fs/Qms, and electrical damping: BL^2/(Re*Mms) ~ Fs/Qes, as well as cone profile (exponential vs. straight) with the associated different cone break-up, etc.

Only if all those important parameters were exactly the same, would it then make sense to speak about any possible remaining differences in sound due to AlNiCo vs. Neodymium vs. ceramic magnets, I think.

I don't mean to say that the magnet does not make any difference - it most certainly does, since no magnet structure is perfect, and e.g. the magnetic field is measurably different in typical AlNiCo vs. ceramic magnet woofers.

But I do believe that to ascribe such major sonic differences as those that you mentioned solely or even principally to the magnet type is probably misguided.

Marco
I think POOH may be right that ceramic is now not top of the list for a new system, certainly not for the tweeter anyway for anything above MP3. But perhaps the good old ceramic is not finished quite yet used right.

Could say more but I will leave it at that. You have got a lovely system so do enjoy.
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Old 24th August 2015, 02:58 PM   #13313
Eldam is offline Eldam  France
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It seems all those magnets and how the density magnetic flux work with a same TS parameter driver for each type of magnet can give a different result at ears.

We read this for a long time, and if not psycho effect it's certainly one of the hardest thing to modelize with a computer and ask certainly a sota knowledge for people like Earl Gedle or good phycisians/mathematic people !

All empirical tests give often the AlNiCo as a winner, but I didn't read any ABX test with this subject.

Nobody talk at least of Electro Magnet speakers which are usefull when it comes to play with a pot for adjust the force of this field... but I surmise at equal TS (BL, QES...) parameters between an AlNiCo and an Electro magnet speaker with a sota PS switched on for more one days will give again a different result (many people found it was important an EMS has its PS switched on for more than 12 hours for a better sound result )

Products

215 EXC SUPRAVOX

Massive group buy with our own tech request to a drivers maker company as Linkwitz does with Seas ?!
massive grup buy todecrease the costs ?

I'm sure there are also here some proffessional purchasers who are able to launch a factory production with a tech request... as some made around CD and drivers re edition around horns projects seing elsewhere !


Or at least is this project must be made around commercial drivers ?

I saw J Gerhardt made it with a wide band high efficienty driver with a brand named Envie (iirc he is not the owner, there is just one guy behind an artisanal production like french EMS Speaker and also Supravox are today !)

At least there is also a problem of sourcing: JG said he found the paper for cone Audax is making the best he found (even today I surmise it's a small production line which products only with order demands)... I surmie myself than the paper made by french PHL drivers maker to be even better because near the ancient treated paper from Audax called Aerogel which was said to sound very natural because a good amount of damping !

Few are talking of the quality of the paper : cone material ! Why ? Not important ?

regards

Last edited by Eldam; 24th August 2015 at 03:12 PM.
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Old 24th August 2015, 03:43 PM   #13314
Kindhornman is offline Kindhornman  United States
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A few comments about magnetic material from what I have learned building drivers. As stated ceramic is the cheapest material, inherently there is nothing wrong with that. What you have to look at is that it is also going to take the most room and causes some real issues when it becomes a reflective surface behind the cone and causes some real serious reversion waves heading straight back through the cone. Also the real issue of the ceramic is that it has the highest amount of eddy currents that are going to affect the motor assembly.

On the Alnico magnets you have to look at the aspect ratio of those magnets and this is usually a long cylindrical shape. This causes a deep motor structure, the reason that the older Alnico compression drivers are deep, that was the driver in those designs, the magnet made them deep and you had to have those long throats to get the phase plug to reach the exit. Another thing to think about is that many of the classic speakers using Alnico are getting pretty old and can use a recharge of the magnet, so unless you are willing to have the speaker recharged and reconed you better think about how old some of these classics are. This may have a lot to do with the difference we are seeing in many of the older drivers, one to another, it may be a bigger real issue than the many different cones people seem to believe are making them all sound so varied. different amount of demagnetization from one to another.

Neo is a generic term. Nobody lists the grade of Neo they are using, there is such a wide range of Neo MgOe values and heat grades that just because it says Neo doesn't mean a thing. It could be some really cheap junk with no more energy than a good ceramic magnet or some really high value material like I am using but that costs a bunch more than the cheap stuff. Don't fall for that, it is now just a marketing tool to say Neo. Neo does have the potential for very high flux density in a very short height magnet, this is one of its greatest advantage and it also can have the very low eddy currents that help to lower the motor distortion. You couldn't make many of the very short high powered and small diameter compression drivers without using Neo material. Same goes for in a cone driver, you have much reduced diameter behind the cone and less reflective surface and still can get really high flux density if you use high quality Neo material.
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Old 24th August 2015, 04:00 PM   #13315
Eldam is offline Eldam  France
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Do you mean it could be better to have a longer ferro magnet instead for example two splited by a copper ring or Something like that like an ideal length of the magnet in relation to the length of the voice col (as well as with its diameter) ?

Is it not also on how the magnet field "floods" the length of the voice col ? Forces not applied on the same way between the different magnets (different mixed materials) ?
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Old 24th August 2015, 04:23 PM   #13316
Kindhornman is offline Kindhornman  United States
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Eldam,
I use a copper Faraday sleeve to handle the eddy currents that can be in the motor assembly, some don't want to give up any of the possible energy and just won't do that but the tradeoff is higher distortion numbers. Neo allows for some really short height magnets, you can add thickness but don't need that much to get very high flux density in the gap. Added diameter goes a long way with the Neo, more than the thickness but after you reach a certain point more energy is counter productive really, at least in a bass driver as you can kill the bottom end with to much energy in the gap. It does make it much easier to make a longer gap height and increase the linear motion of the voicecoil. It takes a very large surface area in relation to the ceramic magnet material to get the energy transfer, a narrower deeper ceramic magnet does not have the same energy transfer function. When you see those double height ceramic magnets this is more to do with increasing the depth to the back plate than really adding to the energy in the gap, it adds some but not much. It allows the coil to move farther without hitting the back plate, this is what is really the reason to do that.

Motor design is a real art, you would be surprised what you see when you start to use one of software modeling programs where the magnetic energy tries to go. It will always want to take the path of least resistance and the shortest loop that it can make. It becomes a real engineering problem of distances between surfaces and any sharp corners and so many things. Leakage paths can crop up in the strangest places and you have to look real hard at what is really happening. You can add more magnet material but if it can take a shorter path it may never get to the gap. And trying to contain the field in the gap without a large external field is also something you have to look at. I always say to me the worst case is the long coil in a short gap, when you start to look at the asymmetrical fields of both the flux in the gap and the field you create with the coil it doesn't look nice at all, it is a crazy idea to think you can make one of those designs linear, it just doesn't really happen. Yes you can get some high excursion but I can guarantee that it will be nonlinear in reality and have higher harmonic distortion, it is just not possible to linearize the motion with the differences in steel on each end of the coil, one end in the air and the other surrounded by the steel structure.

Last edited by Kindhornman; 24th August 2015 at 04:26 PM.
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Old 24th August 2015, 04:30 PM   #13317
Eldam is offline Eldam  France
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Very informativ answer, thanks for that, I didn't know there was enough powerfullpersonal computers to modelize that and thinked it was more about the experience of the designer as the quantity of salt/Pepper as a good trade off.

I saw the very appreciated Altec/GPA in this thread has a patent for its V magnet design
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Old 24th August 2015, 05:02 PM   #13318
Lynn Olson is offline Lynn Olson  United States
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Quote:
Originally Posted by Kindhornman View Post
I always say to me the worst case is the long coil in a short gap, when you start to look at the asymmetrical fields of both the flux in the gap and the field you create with the coil it doesn't look nice at all, it is a crazy idea to think you can make one of those designs linear, it just doesn't really happen. Yes you can get some high excursion but I can guarantee that it will be nonlinear in reality and have higher harmonic distortion, it is just not possible to linearize the motion with the differences in steel on each end of the coil, one end in the air and the other surrounded by the steel structure.
Long coil/short gap, otherwise known as overhung, which is what 99% of the midwoofers and the woofers on the market are. Why so popular? Well, you get the longest excursion with the least amount of magnet material, and customers just love lots of deep bass.

The other way around (short coil/long gap) is surprisingly rare. Very few woofers are made this way. The Altec 416's and 515's, some ATC models, and a few other exotics. I think the famous TAD Alnico models are made this way, but I'm not sure.

Equal-length coils and gaps? That's a guitar speaker, where distortion is a good thing.

Regarding Alnico vs ceramic vs neodymium vs field-coil: when you work with all-transformer-coupled amplifiers with different brands of transformers, you become very aware of the differences between transformers. The signal path is nothing but triodes, transformers, and wires, with no feedback to mask the sound of the circuit. Every part is exposed.

If anyone here has built an amplifier with this kind of topology, you'll certainly recognize the sound of the magnet of the driver. It's pretty distinctive, and doesn't sound like cone coloration at all. It sounds like different permutations of a DHT architecture.

Would a transistor-amp enthusiast recognize this rather unusual coloration? I'm not too sure; it doesn't sound anything like what transistor amps do, which almost never have iron, nickel, permalloy, amorphous, or microcrystalline cores in the signal path. Transistor amps are typically an array of direct-coupled P/N junctions, along with a substantial amount of negative feedback. It's a very different kind of sound.

Last edited by Lynn Olson; 24th August 2015 at 05:28 PM.
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Old 24th August 2015, 05:15 PM   #13319
Kindhornman is offline Kindhornman  United States
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Lynn,
Yes it is the easiest and cheapest way to move lots of air. long coil and short gap. If you want to listen to the sound of a bad car stereo that is the way to go. If you want good clean bass output and are willing to pay for a more expensive design you are never going to get more linear than a short coil in a long gap. Now that is also a relative term as many so called long coils are not really much longer than the gap, perhaps 20% which helps but is still not going to give much in the way of high excursion and linear motion. To me at least, I think this is why so many on this thread like the larger cone size for the bass as at home sound levels those speakers are really just loafing along at that output they are asked to do. To many buy into the doppler shift argument about higher excursion of smaller cone size. I have had Richard Lee, kgrlee, formerly of Celestron and B&W tell me in DBLT you can't hear it, it is a false premise. It is not at all the same as the motion of moving side to side like a train, you can't detect the doppler shift from a cone moving in and out, another audio myth that has been pushed for far to long. Humans do not have that type of sound discrimination over that short a distance, we don't have the hearing acuity to hear over that type of distance front to back with our ears.
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Old 24th August 2015, 05:24 PM   #13320
InOtIn is offline InOtIn
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Thanks to everyone who's chimed in on whether the 416-8B are a good also for rock, metal, pop etc. Just a few quotes re the driver itself:

Quote:
Originally Posted by Pano View Post
But I have to say that for me, in the proper enclosure, nothing beats the 416 or 515. They are clean, dynamic, light where needed, heavy where called for. They do the best job of reproducing natural sounds, be that an upright bass, a djembe, or a steam train crossing a bridge. The Alec woofers (to me) excel at reproducing natural sounds big and small, that's why I like them. They are not what I'd use if installing an EDM club.

Quote:
Originally Posted by POOH View Post
All the 416 and 515's I have sound soft and lack detail, are compressed - they seem to smear the leading edge.

Quote:
Originally Posted by Pano View Post
If by that you mean they don't have the cone cry and nasty breakup modes of most 15 inch woofers, I will agree. If you want a woofer that sounds like a loudspeaker, the 416 and 515 are not for you. They don't have the typical woofer coloration that many people like.

Quote:
Originally Posted by POOH View Post
The altecs have nasty break up and cone cry, I don't see your point. I can't imagine a woofer without those characteristics. Do you have an example? It's the nature of the beast. My point is they are no better than some modern 15's... that sounds "less like a loudspeaker" than the 416 or 515 It's also less expensive and can be had a a zillion on line outlets.

Quote:
Originally Posted by Pano View Post
No, they don't. At least not compared to most pro drivers. And yes, there are some very good drivers on market. But at the top of the game it can become a matter of taste. And that is the point of this thread. No driver or speakers is perfect so we have to choose what bothers us the least. While I do like Tannoy and Celestion and others, they still say to me " Hello, I'm a speaker!" more than the Altecs do. Not everyone agrees which is why we have to find what works for each of us. It's those subtle difference that make up the high end. If money were no object then GOTO and maybe ALE drivers would be on my shopping list. There are very, very good. But within my budget I have not found better than the Altecs. For me, they have the least coloration.

Quote:
Originally Posted by limono View Post
Well , I'm not selling mine (Altecs) .They may not be the end of all things but they do well in most applications.

Quote:
Originally Posted by Scott L View Post
416's can't do PUNCH (you in the gut). I know that's what you want. The Altecs are wonderful for tone, and bass sustained notes. The only way to get the PUNCH is with some variation of reaction-forced canceling woofers. A pair of professional 12's or (better yet) 15's per side can accomplish this...

Quote:
Originally Posted by PeterBracke View Post
They have a smooth very soft compression (similar to SE triode amplifiers)... On some types of music and playing loud, the very soft compression of the 416 might not be wanted. A midwoofer that does not sound compressed and has all the punch is the Precision Devices PD-122.

Quote:
Originally Posted by Lynn Olson View Post
It's news to me that Alnico "gives a softer rendition". That's certainly not what I hear. It's the typical ceramic-magnet pro speakers that sound gray and congested ... that's pretty much how I'd describe the sound of the JBL 2226. Alnico has a lot more vivid tone color and sparkle, which offsets the flat character of most recordings. The few Neo drivers I've heard have a slight tendency towards edginess, which has be subtly toned-down in the crossover.

Difficult to draw some firm conclusion however since people seem to have different opinions on either the qualities of the 416-8B itself or on what's important in this sort of music, especially from myself.

Inevitably, everytime rock or metal is being mentioned, focus is quickly drawn to high SPL, punch and dynamics and then with recommendations about PA gear and then s*** loads of it (drivers & watts).

Yes, I like to crank this sort of music up just as much as anybody else, from time to time, but most of the time I listen to it at moderate listening levels, at the same average volume as any other genre (75-85 dB depending on the presence of wife, kids, dogs, neigbours being home etc). This sort of music is typically recorded with mediocre dynamics, not seldom below 10 dB and in rare cases perhaps up to 15 dB (typically remasterings by the likes of Steve Hoffman, Andy Pearce etc). So not a lot of jump factor, more a wall-of-sound type of feeling.

To me it's much more about the tone and the tonal density, especially in the lower midrange, say 100-500Hz, i.e. in the heart of the midrange where the fundamentals of male vocals and electric guitars live, and drums for that matter except for the kick itself. The tone's got to be right more than anything else to bring out the soul and passion of this type of music!. Most electric guitarists I know or know of obsess just as much about tone as audiophiles, chasing down that vintage alnico driver, tube amp cabs, organic strings etc. There's a lot of human thought and creativity (art) actually going into all that "harmonic distorsion"...

I don't even know if dynamic impact really matters all that much for satisfactory reproduction of this kind of music. I mean most of us grew up listening to, and learnt to love, this type of music on our parents stereos, which probably where quite challenged in this respect (unless your dad was into audio + had the money to pursue it). High dB peaks of crashing cymbals and what have you is sometimes a distraction from the core of the music and often forces you to turn down the volume so much that the average level - the body of sound - loses its impact and drive. Sure, the 60-80Hz kick needs to have the necessary impact but not excessively so (8 x PA 18"). Nobody of sane mind wants to reproduce the live rock concert experience at home, for health and sound quality purposes, nor is this what rock & metal (studio) recordings are trying to emulate.

Also, just like many OB fans prefer the more diffuse imaging and staging a dipole gives, thinking it sounds more real-life than the hyper-precise and etched-out presentation of every instrument and voice of a 'monitor' with lots of space between the performers, that's also how I like my rock & metal. It goes back to this wall of sound and the density hereof that I think is so important for the presentation, and this is where I think a lot of the speakers, that at least I have owned, distract by dissecting everything into several pieces rather than giving it all to you in its wholosity. It's not high resolution or fidelity that is the problem here, which I believe is just as good also for this kind of music (although erring on a darker flavour is better than vice versa), but how they deliver and present the space of the musical experience.

Quote:
Originally Posted by Kindhornman View Post
The current design for the Beyond the Arial speaker is... not a rock and roll speaker system.
No? With a "vivid and sparkly" 15" covering the important range 70-700Hz with a horn loaded CD above (and something appropriate below), I would have thought the BtA could've been an excellent speaker also for rock n' roll... :

Quote:
Originally Posted by Lynn Olson View Post
All of the large-format 15" driver + horn systems have 10 to 15 dB more dynamic range, headroom, lower IM distortion, etc. than standard audiophile speakers....
... but my concern was not the BtA concept in its entirety but the suitability of the 416-8B as the best possible choice for ALL types of music including metal, rock and pop, covering roughly the same range (70-400 Hz) and in a speaker design that addresses other negatives in this passband, such as narrow baffles and floor bounce.

Quote:
Originally Posted by Lynn Olson View Post
I don't want a hifi system that only sounds good on ten or fifteen audiophile recordings done with minimalist miking and a pristine ultra-high-resolution 192/24 transmission chain. I want crappy old LP's and funky mid-Eighties digital recordings to be at least listenable, and not immediately drive me out of the room.

In other words, recordings of great musical performances that we can buy today, not unobtanium master-tapes slowly deteriorating on a dusty shelf in a record-company archive. I know plenty of audiophiles who only listen to the same 15 recordings over and over again, because that's the only thing that sounds tolerable on their systems. An "accurate" system like that will eventually drive the owner away from listening to music, or maybe worse, drive them towards shoot-em-up movie soundtracks.

My personal yardstick for a hifi system is the amount of joy it gives you. Measurements and simulations are a means to an end, not the goal.
This is exactly what I'm talking about - although our playlists may look a bit different.

Quote:
Originally Posted by gedlee View Post
The trouble is that the answer that you don't want to hear is actually the one that is correct. Only a highly accurate speaker will ever have the possibility of expressing a wide variety of musical sources without showing a preference for one or the other.

So very true, I know...

Last edited by InOtIn; 24th August 2015 at 05:26 PM.
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