WIBAQ (Betsy-K) & Singularities (Dayton PS220)

[Scottmoose]

Not by my maths you haven't.

Note that if you have a high output impedance amplifier (e.g. most SET designs) the effective Qt will be higher. For example, say the amplifier has an output impedance of 2.5ohms, which is a fairly common / modest figure for a SET type design. In this case, the effective Qt of the Dayton will rise to 0.511 (and the mass corner frequency will also drop from 244.21Hz to 181.6Hz), and it's this value you should use when designing an enclosure for the driver.

 

[Bayou Self]

So, all those T/S parameters are concerned only with a driver's behavior from Middle C on the piano (262 Hz) and below?

 

[GM]

Not necessarily; consider an 8" Fostex horn driver's specs driven with a typical SS amp's fractional output impedance [super high damping factor], i.e. Qts = Qts' for all intent: 2*40 Hz/0.2 Qts = 400 Hz.

In short, do the math rather than make sweeping assumptions if you want to get the most performance out of a given speaker alignment.

GM

 

[Scottmoose]

Edit -GM beat me to it, but what he said. T/S parameters are valid from 0Hz up to whatever the mass-corner frequency might happen to be. As shown, that frequency varies depending on the driver and / or driver + amplifier output impedance or series R though so you can't generalise it to a fixed point on a piano (or any other) scale.

 

[GM]

Ya know, if we'd had a lick o' sense to do every appropriate response in a 'sticky' over the years, we'd long since be able to just post a link! Oh well, those that don't learn from history are doomed to repeat it!

GM

 

[Bayou Self]

Are all those parameters concerned with the low end of a driver's FR because that's where a speaker can damage itself if pushed too hard in an incorrect enclosure?

 

[Scottmoose]

Ya know, if we'd had a lick o' sense to do every appropriate response in a 'sticky' over the years, we'd long since be able to just post a link! Oh well, those that don't learn from history are doomed to repeat it!

Ain't that the truth.

 

[Scottmoose]

Are all those parameters concerned with the low end of a driver's FR because that's where a speaker can damage itself if pushed too hard in an incorrect enclosure?

No, it has nothing to do with that. Simple electrical filter analogy, which is what T/S parameters basically are, assume a given fixed set of conditions that quickly cease to be of relevance as frequency rises.