Neodymium drivers in Scoops

Marjan. As everybody is thinking, "would it be rude" I'll do it. ~~Deep~~ Dip Thumbs Up

No, I cannot speak Macedonian before you ask Embarrassed

It's everything, not everythink!

When you guys compare sensitivity, do you take into account that the 18NLW9601 has a very low Re?

Simple answer would be the drivers resistance. But things are bit more complicated :-)

Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713

MarjanM wrote:

Simple answer would be the drivers resistance. But things are bit more complicated :-)

No they aren't more complicated. Re is the drivers DC coil resistance, period.

Best regards,
Teun.

So in order to create clarity we should be vague about a term that has a very clear definition?

Corell knows quite a bit about the phsyics of drivers.

And to be honest, a lot of people on here don't.

What he was probably referring to, was that true sub efficiency is primarily dependent on BL and Re, which together determine the ACTUAL motor strength. Reference efficiency means nothing in a sub cabinet if you want to get the most out of a given cabinet/driver combo.

What Elliot is always dragging on about is simply voltage sensitivity, which has nothing to do with actual power efficiency converting amplifier power into acoutstic power, but only constant voltage into acoustic power.

The higher BL^2/Re, the higher the actual electrical efficiency.

But, and there is a big but, you need an amplifier capable of delivering high voltages to the driver!

Per example (from another topic! : http://forum.speakerplans.com/wsx-driver-upgrade_topic98528_page3.html );

Of course brutus may have found his TBX to perform better than the 115 given a constant voltage.

Following Elliots reasoning (which i am not saying is wrong, just irrelevant) the voltage sensitivity of the S115 would be lower than for the TBX in a WSX sub. That is, without corrective EQ applied and using an amplifier not capable of delivering the voltage required by the speaker.

However, if you would apply corrective eq and have the voltage swing capability of a K20 for instance, the S115 would win hands down from the TBX since the electrical efficiency is simply much greater, which matters way more when producing sub than simple voltage efficiency.

If this is something people do not understand, i can suggest to read the following paper;

http://xlrtechs.com/dbkeele.com/PDF/Keele%20(2003-10%20AES%20Preprint)%20-%20Nom%20vs%20True%20Eff%20High%20BL.pdf

edit: I might have gone a bit off-topic LOL

Edited by Teunos - 30 May 2017 at 1:36pm

Best regards,
Teun.

If you simulate with hornresp etc, you will most certainly apply the same voltage (2,83V) to all the different chassis tested. By comparing the sensitivity of a chassis with a Re of 4,7 against a chassis with a Re of 5,5 (allthough both might be 8 Ohm nominal speakers loaded in that particular enclosure), you could conclude that the 4,7 Re one is "more efficient" while in fact you are just "giving" them more power (same voltage + lower resistance).
So you should ideally simulate each driver with 1 w into their passband impedance minimum.