New Joseph Audio Pulsar Graphene 2

pops,

The CS6 was one of my favorite all time speakers (I had them for a while, long ago). I’m still a Thiel guy. I don’t see getting rid of my 2.7s any time soon.

I love having the Joseph speakers too, though.

Obviously no speaker is perfect and I can, like others, pick nits in every speaker I own. But having said that, I get obsessive when researching speakers before a prospective purchase. I have probably bookmarked everything someone said on the internet about the Joseph speakers :-)And I don’t think I have ever seen as close to that much consensus of approval about a speaker brand anywhere else (that I’m aware of).


It's not like everyone wants to *own* a Joseph speaker of course.   But whether it’s reviews, or user reports, or show reports, whether in "objectivist" or "subjectivist" audio forums, and from users of all different types of speakers from panel to horn, people who have heard the Joseph speakers almost always say how impressed they were.Almost any other speaker I can think of seems more divisive.

@erik_squires

In the measurement section of of JA's review of the updated Perspective 2Graphene, JA makes this comment:

the Perspective2’s plot of impedance magnitude and electrical phase against frequency (fig.1) suggest that the speaker is an easy load for the partnering amplifier to drive. However, while the Perspective’s minimum magnitude was 6.27 ohms at 135Hz, the Perspective2’s minimum was a little lower, at 5.36 ohms at 139Hz. The bass impedance peak was also greater, at 34.4 ohms at 59Hz compared with 15.6 ohms at the same frequency for the original speaker.

https://www.stereophile.com/content/joseph-audio-perspective-loudspeaker-perspective2-graphene

Can you enlighten me: What, if any, consequences would this have for driving the Perspective2 vs the original version? I use the CJ Premier 12 tube monoblocks. Are there any implications as to the Perspective2s being harder to drive or whatever vs the originals (which I own)?
Thanks.

What, if any, consequences would this have for driving the Perspective2 vs the original version? I use the CJ Premier 12 tube monoblocks. Are there any implications as to the Perspective2s being harder to drive or whatever vs the originals (which I own)?

Hi @prof

Thanks for trusting me to answer this question.

For a solid state (i.e. low output impedance) amplifier the consequences are probably very little.

As the amp’s output impedance rises (damping factor drops) the frequency response of the amp’s output starts to tracks the impedance. So, the math says that increases in impedance will lead to increases in output. The other thing that is noticeable, and almost coincident is the phase angle is now bigger just above, ~ -45 degrees vs. ~ - 25 for the original. So long as this is coincidental with a high impedance this should not be an issue.

The Perspective 2 isn’t what is normally thought of as "hard to drive" but if you ask if the change in impedance has the opportunity to alter the sound of the amp/speaker combo then yes, it is possible that there would be more output at the impedance peak, how much and whether or not it is unpleasant is another story. :)

Both amps share quite a bumpy ride between the bass (150 Hz) to 20 kHz, but if you already like the sound of the original, I’m sure the new one won’t be much different, with potentially a stronger output at the peak.

You know, I thought I had seen specs from JA which showed the speaker to be impedance compensated. Clearly these two examples are not!

Something you did not ask about: The overall balance.

Based on the impedance, frequency and assuming JA has kept the original tweeter, it looks like he’s not trying to get the tweeter as flat to 20 kHz as before. I would expect the new model to sound a little more relaxed in the top octave.

Neither model exhibits frequency aberrations, so I just note this as a mild shift in goals.


Best,

E

Hi @prof,

For an example, see Stereophile's measurements of the CJ 12.  In particular, the first graph showing the output into a simulated load.

https://www.stereophile.com/content/conrad-johnson-premier-twelve-monoblock-amplifier-measurements

See that bump at ~ 60 Hz?  That's what I'm talking about. :) The greater the impedance of the speaker, the more that bump will rise.

I wrote:

Both amps share quite a bumpy ride

I meant:

Both _speakers_ share quite a bumpy ride