Ribbon v ESLs – which is better

Hi Rick57, It's been a while since I visited this forum so I'm a bit rusty with the protocol, forgive me if I make any blues!!

I don't really understand your query here. Being the designer of all of E R Audios products I feel I should be able to help, perhaps if you can describe more clearly what your question is I can give a response.

Best regards

Rob
 
rick57 said:
Not full range or tweeters, I’m thinking of 200 Hz & up.
Which has greater dynamic ability – playing the loud passages without any compression (or risk of reduced life).
Eg what is the maximum watts rms rating on the ER panels?


if you can somehow get a .6T - 1T field across a 1.5" wide gap I would think the ribbon would sound best... especially cause you talking about dynamic capabilites... a ribbon if you wanna spend the money can have very high efficency and also to my ears sound more dynamic than ESLs

ESLs sound REALLY nice though...

either design I would make two ribbon/2 ESL panels from the frequency range you're talking about

Wide ESLs can play 200 hz well.. but they drop off at 6khz or so... you'll want to make a "2-way ESL"... also the same for the ribbon... like a 1.5 " wide one to say 3khz then a .25 or .5" wide one to 20khz
 
the field strength refers to the magnetic field within the gap where the aluminum/planar material is suspended for a ribbon

the more field strength the more efficent, the more dynamic :)

a .5 telsa (T) field would be amazing across a 1" gap... let alone a 1.5" gap... it would require some big magnets

a ribbon with that much area and a .5T gap if you used 5.8 micron foil would be massively efficent as well and play very well to 200 hz or so (well more like 300-400hz)...

if you can "afford the 1T" field this is most ideal across the gap... this is twice as efficent as the .5T gap... you'd be approaching 105db/w maybe more with this

look for 101/db/w with the .5T and VERY thin ribbon material... somethign like 5.8 micron pure aluminum...

a 1.5" wide ribbon is as small as I would go for what you're looking to do... ideally 2" wide would be best...

the only advantage as far as dynamics over an ESL is that if you have the cash... these will be massively more efficent...

ESLs have lower distortion if done correctly though... unless you really research your ribbons :)
 
The BG's are a aluminum zigzag "coil" printed on a plastic substrate.
"true" ribbons are just a very thin piece of accordioned aluminum between the magnets. The "true" ribbon usually needs a transformer because its impedence is very low, but it is lighter, and some prefer them. I sure like mine...

A major reason for using narrower ribbons for higher frequencies is that they have wider dispersion.
 
Hi Rob

What is the telsa field and normal (or optional) gap in the ER panels?


Hi Audionoob

“a ribbon with that much area” ~ how much area?

“if you used 5.8 micron foil”.
IIRC, ER panels are only 3.8 microns

”a 1.5" wide ribbon is as small as I would go for”
The BG frames are 1.5" wide, I imagine the ribbons are only about 0.75” wide. They’re claimed to cover 150 Hz – 18.5 kHz.

Hi Variac
So BG ribbons are not true ribbons, but quasi ribbons – I believe quasi don’t sound as good, not the clarity?
 
rick57 said:
Hi Rob

What is the telsa field and normal (or optional) gap in the ER panels?


Hi Audionoob

“a ribbon with that much area” ~ how much area?

“if you used 5.8 micron foil”.
IIRC, ER panels are only 3.8 microns

”a 1.5" wide ribbon is as small as I would go for”
The BG frames are 1.5" wide, I imagine the ribbons are only about 0.75” wide. They’re claimed to cover 150 Hz – 18.5 kHz.

Hi Variac
So BG ribbons are not true ribbons, but quasi ribbons – I believe quasi don’t sound as good, not the clarity?


1. A ribbon with 2"x60" long or so... maybe less length than that
2. I'm talking about a ribbon here... not an ESL.... that's 5.8 micron aluminum
3. I would like to see them go to 150hz... if they do their output suffers terribly.... problem with ribbons is that as frequency decreases power handling decreases drastically with skinnier ribbons... max SPL and efficency suffer...... I would look into at LEAST a 1" wide ribbon to go below 1khz and play well there... look for 1.5" at least for 300-400 hz...

with 1" steel and some large magnets... get .5T across 1.5" is possible... magnet costs are pretty high if you want to do a full line source like an ESL

quasi vs. aluminum is different... each have their strengths

one good thing about planars is that they are far lighter than aluminum per a given thickness
 
rick57 said:
"quasi vs. aluminum is different... each have their strengths"

I only know that aluminum ribbons seem to have about the clarity of ESLs, but quasi lack that magic, sounding by comaprson like an off tune radio

Can you elaborate ~ what are the strengths of quasi ribbons?

strengths are they make the speaker massively efficent... and a good planar can sound just like alum tweets people say...

a 2 micron mylar laminated or etched with 1micron of alum/copper would be amazingly lighter than aluminum ribbons... around 6db more efficent than with 5.8 micron pure aluminum

also they are more robust and harder to burn up than aluminum...
 
Hi again, I've been trying to respond to your queries for a couple of days but up until now have not been able to get anything through. Maybe I'm doing something wrong or perhaps because of my long absence from this forum, my posts need to be monitored and accepted by the administrator.

We have not calculated the nominal Tesla field in our electrostatic speakers, as it is not a parameter we are really interested in. ESL's are different to ribbons in that the operating field strength varies greatly with signal levels due to the very high signal voltages used.

The air gap that is chosen depends upon the frequency range you wish to cover and the max SPL you wish to obtain. Low frequency response requires larger diaphragm excursion so requires a smaller gap. Larger gaps affect sensitivity, which is partially improved (but not completely) by increasing the polarising voltage applied to the diaphragm.

Wide panel ESL's do not normally have HF roll-off (in fact quite the reverse) as long as they use good transformers etc. However, HF does become very directional with wide panels, hence the common use of multi panels in commercial designs.

Our products have the air gaps optimised for the individual panels and application. As an example, the ESL III has an air gap of approximately 2.3mm on the bass panels and 2.0mm on the treble panels. While the difference seems small, the field strength is subject to an inverse square law so small changes in gaps create quite large changes in sensitivity (output for a given input).

Martin - Jan's comment about keeping the air gap small for your application is quite correct. If you don't require the speaker to develop deep bass then you don't need large excursion so a smaller gap can be used. Needless to say there is always a trade-off. Smaller air gaps for a given panel size increases the capacitance of the panel. This is reflected back to the driving amplifier by the square of the turns ratio of the audio transformer. So, an increase in say 500pf panel capacitance will mean that there is an additional 5uf capacitance to drive with a 1:100 turns ratio transformer. This is a significant increase in load for the amplifier.

However, as the sensitivity is higher, you may be able to reduce the panel size, reducing capacitance.


Treble dispersion is affected by the width of the surface radiating the high frequencies. Narrow transducers have better horizontal dispersion but have reduce area to create the sound. A reduction in air gap helps to improve output for a given input.

We have selected an active width of 40 mm forr our treble panels as this gives a combination of good dispersion and output.

Hope this helps
 
Rob

Thanks for explaining this. You should contact an administrator re your posting problem

Audiophilenoob’s suggestion of a "2-way ESL” eg a 1.5 " wide one to say 3 khz then a .5" wide (or in fact 40 mm) one to 20 khz, and your approach of air gaps optimised for individual applications sounds great.

I'll contact you direct when ready to proceed.

Cheers