why ribbons may sound subjectively better than domes.

[thadman]

I was wondering why everybody raves about ribbons...yet they measure so poorly. Specifically the Aurum Cantus G3si was measured to exhibit 1.6% 3rd harmonic distortion at 7khz at 90dB. In fact, their only redeeming qualities include incredible horizontal dispersion and high sensitivity (ie dynamics).

G3si @ 96dB @ 1/2m


Vifa D26CN55 for comparison

Also 1.6% may not sound like a lot, but the order of distortion needs to be taken into account.

.... one study I've seen that says the audibilty is a function of the square of the HD order. So the 3rd harmonic only needs to be something like half as loud as the 2nd for equal audibility. Crunching the numbers:

Order % HD for equal audibility
2 1.00
3 0.44
4 0.25
5 0.16
6 0.11
7 0.08
8 0.06
9 0.05

Several other studies confirm the concept if not the exact numbers. So, just looking at 2nd and 3rd harmonics doesn't tell the whole story. The higher order harmonics are much more audible even if they don't contribute much to THD.

I was pondering over this...objectively theyre horrible but no one seems to be bothered by it...and it hit me! The distortion performance (especially higher frequency distortion) may be inaudible. A 3rd order harmonic of 7khz is 21khz, thats beyond the realm of audibility and surely wouldnt bother anyone of reasonable age...maybe toddlers lol. Even higher order products in the lower frequencies such as 3-4khz shouldn't be too much of a concern, as (although less severe) we are still much less sensitive in the 7-11/12khz range.


After observing this equal-loudness curve, we can come to know that we are extremely insensitive at high frequencies compared to the midrange.

Things such as off-axis response and linear distortion may be much more important.

I'm sorry if this has already been discussed or established, just a hypothesis/conjecture on my part.

discuss

[cotdt]

i think you are absolutely right. it's more than just a conjecture, it's supported by psychoacoustic evidence.

[gvinson]

"Things such as off-axis response and linear distortion may be much more important"

IMHO....."ARE" more important.

[Jed]

Not all ribbons measure poorly above 3-3.5k. In fact, the Fountek CD3.0 is pretty good.

[cotdt]

Yeah, cross a good ribbon tweeter above 3kHz and subjectively they sound very nice, to me better than the best domes. A lot of their distortion actually comes from the transformer, and in the future I think that ribbons would be the cheaper and better solution because some special amps can drive the ribbon directly. ribbon tweeters are also very easy and cheap to make at home.

PS. More than just the wider dispersion is responsible, but I will keep my theories to myself until I can get access to an anechoic chamber to do special measurements showing the superiority of ribbons.

[thadman]

Not all ribbons measure poorly above 3-3.5k. In fact, the Fountek CD3.0 is pretty good.

Isnt the Fountek CD3.0 share a lot in common with the Aurum Cantus G2si? Maybe I'm thinking of the Fountek JP3.0?

Do the smaller ribbons have less energy storage problems below 3-4khz? The drivers (at least those Zaph measured) were pretty horrible in that regard.

Those Aurum Cantus' are on sale at partsexpress for $59/pop, how low can they go without energy storage problems? I'd like to play with them a bit, compare them to the Seas and send back whichever driver I prefer least. Does partsexpress allow you to return drivers if they arent scratched? Can they handle a 2500-3000hz crossover? I don't necessarily trust the manufacturer's recommendation...

"Things such as off-axis response and linear distortion may be much more important"

IMHO....."ARE" more important.

It was a hypothesis...I don't think its a good habit to go around preaching my conjectures and ideas as fact. I haven't really looked in depth at linear distortion or off-axis response, enough so to offer substantial proof that those aspects make ribbons superb drivers.

[Jed]

Isnt the Fountek CD3.0 share a lot in common with the Aurum Cantus G2si? Maybe I'm thinking of the Fountek JP3.0?

Those Aurum Cantus' are on sale at partsexpress for $59/pop, how low can they go without energy storage problems? I'd like to play with them a bit, compare them to the Seas and send back whichever driver I prefer least. Does partsexpress allow you to return drivers if they arent scratched? Could the 831882 mate seamlessly with the CD3.0 or G2si?


It was a hypothesis...I don't think its a good habit to go around preaching my conjectures and ideas as fact. I haven't really looked in depth at linear distortion or off-axis response, enough so to offer substantial proof that those aspects make ribbons superb drivers.

Fountek and AC G2si are different, and there are some tests to prove the Fountek is a better performer. Zaph et al. From what I've seen, not experienced, G2si is good down to 3K LR4, and G2 down to 2.5K LR4. I asked the same question you did and that was what Dennis Murphy suggested to me about the crossover points if I recall.

[thadman]

Fountek and AC G2si are different, and there are some tests to prove the Fountek is a better performer. Zaph et al. From what I've seen, not experienced, G2si is good down to 3K LR4, and G2 down to 2.5K LR4. I asked the same question you did and that was what Dennis Murphy suggested to me about the crossover points if I recall.

Are there any benefits beyond better vertical dispersion for going with smaller length ribbon? The bigger brother of the NeoCD3.0, the CD2.0 (ribbon is 120mm long vs 60mm long) did fairly well on Zaph's test but I still wouldn't want to cross it <3khz. The higher order stuff starts getting pretty crazy. How does the CD3.0 compare to the CD2.0? Ahaha...I'm ascending a slippery slope...the CD3.0 is only a little bit more than the G2si...the CD2.0 is only a little bit more than the CD3.0...

I've heard a debate centered around true aluminum ribbons vs fountek ribbons, is there any substance to this argument (aluminum > fountek's material)

[cotdt]

no the ribbon material doesn't matter. the raal ribbons seem to test pretty well and somebody should try them. but in any case, you'd want to cross high. and for the record, these conjectures you make are nothing new but stuff others and i have been arguing for the past two years.

[thadman]

no the ribbon material doesn't matter. the raal ribbons seem to test pretty well and somebody should try them. but in any case, you'd want to cross high. and for the record, these conjectures you make are nothing new but stuff others and i have been arguing for the past two years.

I never claimed it was groundbreaking or anything, just something I had been thinking about and was curious if others felt the same way.