General questions on TSP's

[Kay Pirinha]

Hi,

I'd like to know how I could discern if a driver is suitable for a closed box, a vented box or a horn design? Which TSP's are important for this, and why?

TIA and best regards!

[RMC]

Hi Kay,

This is from Eminence speaker manufacturer's web site, section "Understanding Loudspeaker Data":

"EBP
This measurement is calculated by dividing Fs by Qes. The EBP figure is used in many enclosure design formulas to determine if a speaker is more suitable for a closed or vented design. An EBP close to 100 usually indicates a speaker that is best suited for a vented enclosure. On the contrary, an EBP closer to 50 usually indicates a speaker best suited for a closed box design. This is merely a starting point. Many well-designed systems have violated this rule of thumb! Qts should also be considered."

Usually, drivers more suitable for horn loading have EBP going more towards 200. But again this is only approximate since JBL, for example, made a number of drivers with EBP in the hundred something and they are specified for horn loading use, as well as other boxes...

So its not that simple. I noted that more often than not drivers suitable for horn loading tend to have low Qts number and higher sensitivity. The best way to know in practice is to look at each driver's data sheet where the intended use and box loading are mentioned. You'll see some surprises, like 2225H, 2240H, K-151, E-155, etc.

Regards,

Richard