tweeter

[Johan Jonker]

A friend gave me two tweeters.
Does anyone know what brand or type they are.

Kind regards
Johan Jonker

[Cal Weldon]

Johan,

You'll have to provide as much information as you can on them.

Where did your friend get them?

Are there any numbers on the back or anywhere?

What are they made of? They appear to be a cast material.

Cal

[cph2000]

I would gues it is a ribbon tweeter working acording to "heil motion transformer" principle. Never heard one - but should be top shelf stuff

[Sjef]

They are old versions of the smaller ESS air motion transformers. Sensitivity is pretty high at around 95 to 96 db/2.83V/m. Impedance is constantly flat around 6 ohms.

The newer ones have a lower impedance and lower efficiency but can also be crossed lower also a lower.

I have measured them and used them and can advise you that they do need some form of correction. Without correction they sound a bit harsh with little top end extension. Onces smoothed out (notch filter for the bump between 7Khz and 13Khz) they sound pretty good, at least better than most dome tweeter I have heard, but I can advise a crossover frequency of at least 4kHz, lower is possible but higher sounds better.