Aurum Cantus

[jerrald]

I want to use 12 Aurum Cantus G3Si ribbons, per channel, in a line array. Will I have a problem crossing them over at their minimum frequency response of 1,400 Hz? I will be using 4th order L-R slopes.

[paul_n_oneal]

> I want to use 12 Aurum Cantus G3Si ribbons,
> per channel, in a line array. Will I have a
> problem crossing them over at their minimum
> frequency response of 1,400 Hz? I will be
> using 4th order L-R slopes.

If you're not stuck to Aurum Cantus you could use one of the long BG planars. 24 AC will cost you $5032.08 while the B&G 75 is $753.50 and goes quite low. They only reach up to 18,500 but that's more than enough IMHO. Just a thought for saving some cash.

Paul

[jerrald]

> If you're not stuck to Aurum Cantus you
> could use one of the long BG planars. 24 AC
> will cost you $5032.08 while the B&G 75 is
> $753.50 and goes quite low. They only reach
> up to 18,500 but that's more than enough
> IMHO. Just a thought for saving some cash.

> Paul
Actually, I am stuck on them. Some time ago I posted an idea to build a line array with a row of ribbons between two rows of mids.
If my math works out then this is what I came up with: Aurum Cantus AC-130MkII 5.5" bass/mid + Aurum Cantus G3Si 5.5" ribbon tweeter + Aurum Cantus AC-130MkII 5.5" bass/mid; 5.5" + .25" (gap) + 2.9375" + .25" (gap) + 5.5" = 14.1875" driver width. The CTC of the drivers would be: 5.5" (bass/mid's CTC) + .5" (total of gaps) + 2.9375" = 8.6875".
To figure the minimum crossover point: 13560/8.6875" = 1560.86 Hz. But because this design presents a horizontal MTM the crossover point must be as low as possible. This is why I was asking if 1400 Hz would be a safe crossover point.
I will only consider the BG RD75 if this idea doesn't work.

[paul_n_oneal]

Sorry, I'm not familiar with line arrays. Jim Griffin (spelling?) is the line array guru and has a white paper on the net. A few here are familiar with line arrays more than I and should be able to help you out.

Paul

[dthomas]

Provided Link: http://www.aurumcantus.com/


> Actually, I am stuck on them. Some time ago
> I posted an idea to build a line array with
> a row of ribbons between two rows of mids.
> If my math works out then this is what I
> came up with: Aurum Cantus AC-130MkII
> 5.5" bass/mid + Aurum Cantus G3Si
> 5.5" ribbon tweeter + Aurum Cantus
> AC-130MkII 5.5" bass/mid; 5.5" +
> .25" (gap) + 2.9375" + .25"
> (gap) + 5.5" = 14.1875" driver
> width. The CTC of the drivers would be:
> 5.5" (bass/mid's CTC) + .5" (total
> of gaps) + 2.9375" = 8.6875".
> To figure the minimum crossover point:
> 13560/8.6875" = 1560.86 Hz. But because
> this design presents a horizontal MTM the
> crossover point must be as low as possible.
> This is why I was asking if 1400 Hz would be
> a safe crossover point.
> I will only consider the BG RD75 if this
> idea doesn't work.

The folks at Aurum Cantus are pretty good about asking questions. With that many and considering it has a pretty flat impedance it may well be fine. But they should be able to answer your question.

Just a little curious why you would not just do one row of mid woofers? Also combing will start at about one half the number you came up with. But you should be ok as it should not be too severe. It is really dependant on how far away you listen from. If you are in the nearfield combing will occur at a much lower frequency than if you are at the edge of the transition of near to far field.

There is a progam called the edge that you can download for free at tolvan.com just click on products/downloads that will give you an idea of what your response will be with that type of baffle arrangement. You will have to model the midwoofers and the tweeters seperately. The tweeters should work just fine. It will also show how different listening distances are affected.

Dave

[thylantyr]

> Actually, I am stuck on them. Some time ago
> I posted an idea to build a line array with
> a row of ribbons between two rows of mids.

Aside from the standard CTC issues which IMO
can be cheated, another issue to look at is.
A line of mids has potential to generate more
SPL than the line of G3si ribbons if you design
it as such. Now adding an extra row of mids as you
suggest is just adding to the problem because your
tweeters are the SPL bottleneck.

You be designing your mids to output SPL levels
that match your tweeter, so the extra mids aren't
really bringing much to the party.

You can get amazing high SPL and low distortion
with a single row of quality mids, plus if you
optimize the performance of both mid and tweeter
lines, you can do some damage with a standard
line array configuration.

You can take advantage of lower impedance wiring
to boost performance, you can get better signal
processing and uber high amplifier headroom that
helps to make your line array awesome. You
can also get into a higher grade of midrange
than using 'double row' regular grade mids.

You can do alot with a standard design, exploit
all those options first before making your
recipe too complex.

[Paul Carmody]

Stuck with 24 G3Si? Let me take some of them off your hands.

[jerrald]

> Stuck with 24 G3Si? Let me take some of them
> off your hands.
I have alreadfy discussed this idea with several people and they said it woild work as long as I crossed the ribbons as low as possible.
I'm just not too familiar with the Arum Cantus ribbons to know if such a low cross over point is safe. I also considered the Fountek's but Fountek said the drivers would have too much distortion at such a low cross over point (1,200 Hz).

[rickcraig]

Provided Link: Selah Audio


> I want to use 12 Aurum Cantus G3Si ribbons,
> per channel, in a line array. Will I have a
> problem crossing them over at their minimum
> frequency response of 1,400 Hz? I will be
> using 4th order L-R slopes.

I wouldn't cross them that low.