I would still like more than 10watts. These speakers need to handle very high SPL as they are just as much designed for being main studio monitors as hi-fi use. Most people will listen a lot more than 1m away and what about transient peaks?
Is the F1 really the only commercial amp out there?
Thanks for your advice on all this by the way.
Is the F1 really the only commercial amp out there?
Thanks for your advice on all this by the way.
Tenson said:
It is. I just gave this most important reason generally - not specifically to your application. Specifically for your application it would be the higher output impeadance.
Again, in an active configuration it will almost certainly be enough for home use or proffesional monitoring.
and yes, it is the only commercial amp out there (well in addition there is the F2 and soon to be F3).
Okay thanks. Maybe I will try the F1 and see what happens. I asked RAAL a minute ago what they thought of running the ribbon direct from a current source.
They refuse to give free samples though :'(
I could always build my own amp with my friends help I suppose.
They refuse to give free samples though :'(
I could always build my own amp with my friends help I suppose.
Hmm maybe i'm not getting something, What is exactly mean't as a trade-off between damping and resolution. What exactly is defined as "resolution" and how would damping hurt this. Also scott mentioned that fiberfill tends to kill the best properties of a ribbon, What properties of a ribbon are you refering to and how does fiberfill affect it.
angsuman said:
Damping is a form of friction or resistance. The more damping provided, very small signals cannot appropriately move the diapham in a linear manner and thus small signals are lost. Too little damping, the ringing of the ribbon will effect the current signal and mess up the sound.
I mentiond the idea of using a current amp or an amp with high Zout to drive a ribbon to someone I know. I think they have a good point...
"Measure a ribbons impedance. It is usually completely flat. What that means is that coupling between ribbon and magnet is so poor that no electrical damping occours. So the ribbon doesn't care at all about the source impedance and of course none of the factors that make current drive desirable in moving coil drivers apply to ribbons anyway.
You could not drive the ribbon directly from a current amp. If you have a ribbon with a 0.05 Ohm Resistance and you use a transformer to match it to 6 Ohm you have a ratio of 10:1. What this means is if you use a 50W/8R Amplifier into the ribbon with transformer, it will draw 2.5A RMS from the Amplifier. HOWEVER, the ribbon itself, from the transformer, will be drawing 25A RMS.
So to drive the ribbon directly you need to build an amplifier that can drive several dozen ampere into a dead short. Doable, but no common designs exist and you cannot simply convert a normal amplifier, unless it's one that can drive these kind of currents into dead shorts for indefinite time."
"Measure a ribbons impedance. It is usually completely flat. What that means is that coupling between ribbon and magnet is so poor that no electrical damping occours. So the ribbon doesn't care at all about the source impedance and of course none of the factors that make current drive desirable in moving coil drivers apply to ribbons anyway.
You could not drive the ribbon directly from a current amp. If you have a ribbon with a 0.05 Ohm Resistance and you use a transformer to match it to 6 Ohm you have a ratio of 10:1. What this means is if you use a 50W/8R Amplifier into the ribbon with transformer, it will draw 2.5A RMS from the Amplifier. HOWEVER, the ribbon itself, from the transformer, will be drawing 25A RMS.
So to drive the ribbon directly you need to build an amplifier that can drive several dozen ampere into a dead short. Doable, but no common designs exist and you cannot simply convert a normal amplifier, unless it's one that can drive these kind of currents into dead shorts for indefinite time."
angsuman said:
It isn't about a ribbon, but you might take note of the comments dialogue I participate in here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=75940&pagenumber=2
ScottG said:
I can understand what you say when using valve amps, but for solid state I cannot follow. The impedance that manufacturers mention on amps is the minimal impedance of the speaker without causing the amp to get destroyed by too high currents. But that is usually NOT the output impedance. It would be rather bad for a solid state if it had an impedance of 8ohms, usually it is well under 1 Ohm. By the way impedance is not really a set value but depends on the frequency, so the impedance on a speaker is usually the minimal impedance and mostly the nominal impedance meaning that a speaker with 7 Ohms (minimal impedance) would be still rated as an 8Ohm speaker and a speaker with 2.5Ohms would still go as a 4ohm speaker.
If you want a high impedance output then simply use an 8ohm resistor in series to the tweeter, according to your theorie (which I am not disputing) that should work.
It would also waste a lot of your power. Try a resistor to see how it sounds by all means but re-gig the feedback network if you want to do it properly. As my friend pointed out though, for high efficiency drivers this is all very well but for ribbons it seems pointless.
I've been coming back to that old thread many times over the years..
Why do ribbon tweeters don't sound good if crossed over lower than 6-7kHz?
Well, at 6kHz the 3-rd harmonic would be at 18kHz and would already be in the human hearing range. That means that the non-liner distortion in ribbons is always present and by selecting a x-over above 6kHz we push the products of it above the human hearing range
I never managed to grab hold of aluminum wrapping sheet and move it through the air no matter how slowly I would do that and not hearing the aluminum sheet crackling sound. It is the nature of the material I guess.
Why do ribbon tweeters don't sound good if crossed over lower than 6-7kHz?
Well, at 6kHz the 3-rd harmonic would be at 18kHz and would already be in the human hearing range. That means that the non-liner distortion in ribbons is always present and by selecting a x-over above 6kHz we push the products of it above the human hearing range
I never managed to grab hold of aluminum wrapping sheet and move it through the air no matter how slowly I would do that and not hearing the aluminum sheet crackling sound. It is the nature of the material I guess.
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"a ribbon driver uses a strip of aluminum
foil ribbon as a diaphragm. It is
suspended between the opposite poles of
two magnets. As the signal current passes
through the electrically conductive ribbon,
it interacts with the magnetic fields. This
causes the ribbon to move back and forth,
creating sound."
The simplest electro-mechanical device for creating sound waves did not change that much over the last 50 years. 🙂
foil ribbon as a diaphragm. It is
suspended between the opposite poles of
two magnets. As the signal current passes
through the electrically conductive ribbon,
it interacts with the magnetic fields. This
causes the ribbon to move back and forth,
creating sound."
The simplest electro-mechanical device for creating sound waves did not change that much over the last 50 years. 🙂
Well depends on the manufacturer. They each have their spin on the function of the ribbon. This could be magnet shape, weight, and material. The ribbon can vary from the same parameters, as well as material finishing. All function the same, just implementation of said parts result in diffent characteristics.
Viawave GRT145 as an example, has a mylar surround that seals the gaps to the left and right of a true-ribbon. They also have used diagonal pleats in the membrane.
LCY uses a ribbon with a vertical pleat down the middle to change the polar response.
RAAL uses the jagged exit of the slot in the faceplate and different transformer materials.
Oskar Heil started the AMT sector, which can dramatically reduce distortion if done right, as well as increase sensitivity. The current Airborne/Hygaeia RT5002 of this type is really low HD.
There are many ways to skin the ribbon,
Wolf
LCY uses a ribbon with a vertical pleat down the middle to change the polar response.
RAAL uses the jagged exit of the slot in the faceplate and different transformer materials.
Oskar Heil started the AMT sector, which can dramatically reduce distortion if done right, as well as increase sensitivity. The current Airborne/Hygaeia RT5002 of this type is really low HD.
There are many ways to skin the ribbon,
Wolf
1) ribbons have higher distortion because they have virtually no xmax, so they "hit the wall" dramatically. I've never blown up a dome but I've exploded ribbons.
2) ribbons sound "airy" because they send very little output into the ceiling or the floor. You can measure this, dome tweeters suffer from a lot of comb filtering caused by reflections. Just set the gate on REW to about 4+ milliseconds and you'll see it.
3) It is possible to make domes and compression drivers sound like ribbons but Lordy do you need to know what you are doing. It is not easy. You need a very good waveguide and a very good xover and a very good dome or compression driver. 90% of the candidates will not work.
I definitely think ribbons have their place, I'd probably use them more if they cost half as much.
2) ribbons sound "airy" because they send very little output into the ceiling or the floor. You can measure this, dome tweeters suffer from a lot of comb filtering caused by reflections. Just set the gate on REW to about 4+ milliseconds and you'll see it.
3) It is possible to make domes and compression drivers sound like ribbons but Lordy do you need to know what you are doing. It is not easy. You need a very good waveguide and a very good xover and a very good dome or compression driver. 90% of the candidates will not work.
I definitely think ribbons have their place, I'd probably use them more if they cost half as much.