how good are AE2 speaker

[JohnW]

The issue is that amplifiers are specified into 8R load. A 50W/8R that can comfortably drive 100W into 4R requires a current limit of over 7A. A 100W/8R can have as low as 5A current limit and only drive 4R load to 50W. The first amplifier will drive these AE2s better.

Correct - indeed for most modern day speakers with low impedance dips they need Current rather then voltage swing - its hard to change the mindset that most of the time its not "Watts" you need but peak current - especially for smaller bookshelf speakers with there demanding impedance dips.

Giving rise to this misunderstanding is that most "Low Wattage" amplifiers also cannot provide the current so its hard to despell this notion...

The little MINP amplifier I'm designing is "Only" a 50W per channel design but has 10 output devices per channel and although "only" a 200VA transformer (due to size limitations of the unit) has plenty of Bulk capacitance which in combination with the multiple output device can provide significant peak currents to drive real world speakers loads to very decent levels without sounded "stressed".

 

[JohnW]

So current is no longer related to power??

In the old days, P(W) = I^2 X R

As Davidsrsb has already correctly replied, related yes! but into low impedance loads you need current rather then voltage swing...

You can have a 1KW amplifier that can swing 1000V but only supply 1A, or on the other end of the scale an amplifier that can swing 1V at 1000A both are 1KW capable amplifiers when used with there correct load....

Its the load impedance that matters when partitioning your V & I requirements - current matters as the AE2 are 4 ohm speakers calling for current over voltage to drive them (compared to an 8ohm speaker).

 

[davidsrsb]

The AE3 was even worse, dropping to 3R at 100Hz and 4kHz. Even with this, it was an inefficient speaker

Remember when Crimson were selling amplifier modules - they sold both 8R and 4R optimised designs. You would definitely want the 4R version for these AEs

 

[JohnW]

The AE3 was even worse, dropping to 3R at 100Hz and 4kHz. Even with this, it was an inefficient speaker

Remember when Crimson were selling amplifier modules - they sold both 8R and 4R optimised designs. You would definitely want the 4R version for these AEs

Gosh, 3R at 4KHz is going to stress an amplifier reproducing female vocals...

 

[RustyB]

I've driven AE2's with amps as diverse as a NAP 90 at one extreme, to a Muse Model 160 at the other.

One thing to note about the AE2's is that, with a powerful amp, they will go VERY LOUD, all the while staying very clean.

Jeff Beck's Guitar Shop on vinyl, through the Muse, at stupid volume was absolutely killer.

 

[davidsrsb]

With AE2s you have to be very clear which version you are talking about. The original design with 24dB/octave crossovers is very different to the "Signature" version with 6dB/octave. With those metal drivers, pushing the later versions hard could be painful

 

[RustyB]

To be crystal, then, this was referring to the originals, 1989 vintage, on the dedicated stands.

 

[S-Man]

You can have a 1KW amplifier that can swing 1000V but only supply 1A, or on the other end of the scale an amplifier that can swing 1V at 1000A both are 1KW capable amplifiers when used with there correct load....
.

Being pedantic, you are describing a 500W RMS amplifier. For 1KW you need 1KV RMS and 1A RMS etc (i.e. +/- 1.41KV and +/- 1.41A peak - or "swing" as you call it).

 

[Robert]

Realistically, the ability to maintain voltage drive, i.e. double the current delivery as impedance halves, is only of practical importance at LF and possibly the lower mid frequencies where power demands are proportionately higher for the same SPL at higher frequencies.

You can present some pretty challenging loads to 'small' amplifiers and if there is no/little program content at LF they'll play surprisingly loud and clean.
There are exceptions where loud sounds are required in large rooms, or where the amplifier designer has been a bit dim and left the thing wide open at ultrasonic frequencies.

The amplifier sees the composite loading of the loudspeaker - determined by the intrinsic load characteristics + the program requirements and it's spectral content.

Fot this reason it's often perfectly ok to use current limited amplifiers with loudspeakers using say 8 Ohm bass/mid drivers with 4 ohm tweeters.....or even 2 ohm tweeters.

Consider this.
Most dome tweeters will fry if driven beyond a few watts for more than a few seconds.
The situation for many small mid/dome cones isn't much better. The ratings are comparatively low compared to bass drivers. So if your nominal 100w/8R amplifier can only muster 30w/2R it'll likely sound perfectly fine if the impedance dip is confined to HF.

 

[davidsrsb]

It's not just the current, some amplifiers have abysmal distortion specs into 4R and less, especially at higher frequencies