New Joseph Audio Pulsar Graphene 2

I wrote:

Both amps share quite a bumpy ride

I meant:

Both _speakers_ share quite a bumpy ride

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.

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

@prof 

Yeah, we went through that in this thread :-)

Exactly, but it seems like it's all new again. :)

Guys,

Read the seas white paper on the graphene mid woofer.  They make it pretty clear it is an oxidation retardant.

They also make it clear they have made significant improvements to the motor.

It really makes you double think your choices when you sell something that quickly!! :D

Erik

Hey 'E' : " ..You can totally see that" ?

It's astonishingly amateurish, unprofessional, wrong and insulting.

Here was my question: " ..Can you please tell me if the woofer/tweeter are 'bolted-in' (or wood-screwed-in) "

It raises alarm bells ? The company felt 'threatened' when a customer took the time to contact them directly inquiring about simple, basic design elements -FOR A $10K loudspeaker !!! Too funny.

You don't agree and that's as close as we'll get.
Consumers do not have a right to know everything about a speaker they are buying. There is no right to have a schematic and part list either.

I will repeat that I would not have replied how he did, but I also can see his point of view. The mistake was in the tone. He should have said to please evaluate the speakers based on their sound quality and see if they are right for you.

I do suspect that JA gets an inordinate amount of attention from DIY'ers who want to clone his speakers, and that may predispose him to being more firm in his replies. I don't know.

Best,

E

A few years back, I contacted Joey Audio to inquire about basic build quality/construction details of a particular model. Specifically driver-to-baffle attachment method (bolted or wood-screwed) and baffle material -wood, metal, composite whatever.
In no time flat did I receive an accusatory response suggesting I was looking for information regarding a DIY build -for myself !!!!???  

I can totally see that. These are not really questions which are often asked except by people looking for trade/construction secrets. While he could have simply declined to answer, I can also see his view point.


As I've written before, compared to a lot of commercial speakers, the part to purchase cost is very fair here. You could pay a lot more if the speakers said Gamut or Wilson.  JA speakers are a decent value, based on parts alone, more so if you like the sound quality.


Of course, some keep trying to price the steak they eat and insist that's how much the meal should cost.  Woe to them.

Best,
E

I think 2 feet from the back wall to the tweeter is not enough space for any speaker.

Really depends on the speaker, and the room's inherent gain, and how it was designed. Rarely  you'll get true bookshelf speakers, and they need close wall reinforcement. I've designed some, and the only other one I know of like this is the Crystal Cable Minissimo Diamond.   Wilson also from time to time makes speakers like this.

Oh, and let us not forget Allison, who famously insisted that speakers should be against a wall, and designed accordingly.

That's kind of a shame, as you'd hope an upgrade would sound better somehow. :)

I appreciate the experience and knowledge you bring to this, erik.

I personally am downplaying my own expectations of what I’ll hear with the new graphene version.

Thank you for your kind words!

I’m not saying it’s not a better driver. I’m just saying Seas did a lot of work in the motor. Let’s not get twinkly eyed over the word "graphene" as being the cause. :)


While I cannot tell you how well the new version sounds, I can tell you with some certainty based on specs that the old and new driver require different crossovers, so the idea that they would require a great deal of rework and possibly ending with a different sound is not surprising to me at all. From what I saw of the previous version, his crossover was impeccably designed, with attention to detail and a nod to tube fans. I would expect JJ to take the same level of care with this one.


Best,


E

Reading the Seas graphene white paper, I noticed that while they go into some detail about manufacturing, and oxidation inhibition I didn't see any major claims for it affecting the sound of the drivers. 


Being a serious driver manufacturer, I'm sure they would not make claims they could not back up, or fail to mention benefits if there were any. 


On the other hand, the paper on the 6" or so Magnesium/Graphene driver lists a number of improvements to the motor. 


I'm in no way disparaging Seas or Joseph. I'm sure they make excellent products, and as I read it, the new driver is improved, and will be less likely to oxidize. All good things. 

Predicting changes in sound based on specs is hard to do. Have you heard these speakers?

I make no claim to. I'm only stating that several improvements in the motor structure have occurred, and that I would guess these improvements are probably more important than the graphene coating. 



Best,


E

Hey @markalarsen :

Yes, what's interesting is that they discuss graphene mostly as being a protective coating. If you read the paper on the driver itself, it is clear that several improvements have been made to the driver motor, and that these are likely to be the source of most changes in the driver properties, which are subtle, not really earth shaking. The resonant peak expected with any mid woofer, but especially metal cones is still there.

Best,
E

I’m going to leave my prior work on this subject here, and then stop. The OP deserves to have this thread focused on the original topic. Not my personal views on the reliability or lack of a particular reviewer.


Here:
https://speakermakersjourney.blogspot.com/2016/05/stereophile-reviews-data-doesnt-lie.html


and here we show he’s not sticking to his own claims:


https://speakermakersjourney.blogspot.com/2016/12/stereophile-data-part-ii.html


and here is a great example of JA not understanding the data he’s’ looking at. NOT the first time:
https://speakermakersjourney.blogspot.com/2016/09/stereophile-slanders-crystal-cable.html


Last posting I make in this thread. Anyone wanting to discuss, we need to take it to another thread out of courtesy.


As always, please please buy what you like. It's your money. Enjoying what JA enjoys won't upset me one bit.  Just don't ask me to support a claim he's all that knowledgeable or unbiased. He IS the bias.

Prof - If you like JA that’s fine. Follow him to the ends of the earth.


I find his descriptions curiously slanted towards B&W as his reference, and if it sounds like that it is good and if not, it’s bad, and they aren’t that neutral sounding, objectively or subjectively.


As for me, I don’t need JA to tell me what a good speaker is.


As my blog has shown, he likes a particular type of ragged treble, which to those of us who haven't lost much of our hearing, is a hearing aid. If your tweets match this odd signature, he’ll praise it, and otherwise pooh pooh it. JA is exactly why DIYers give High End audio such a bad wrap. He has crap taste, bad hearing and we’d never deliberately build anything he thinks is superb.


Essentially JA has lost his hearing and wants you to hear like he does, and for the most part he's accomplished it.

JA is really good at measuring, which makes the fact that he can barely interpret his own measurements more than a little frustrating.


He likes speakers that sound like hearing aids, and he is not above making up shade. If he hears things others miss, it’s probably because he made it up.


Feel free to like or dislike the Pulsars as you see fit, but using JA's opinion as to sound quality is not something I'd ever recommend.

JA at Stereophile is the last person whose hearing I would trust. He's part of the B&W/Golden Ear cadre, and wouldn't know a neutral speaker if he sat on the plane next to one.

We aren’t 12 year olds.

That was a veiled threat any reasonable adult would know not to post unless that was his intention.

It has no place here.

Hey NYAudio98, it sounds like you are threatening another member. I have reported you to the admins.
Have a nice day.

Look at the Stereophile CJ Premiere 12 chart.  The simulated speaker load they use is pretty close to what the Pulsars have.  Shows about 0.5 dB boost.

Perfectly manageable with placement, and of course, in a good room. :)

@erik_squires & @prof Erik’s prediction was mistaken. They are slightly more efficient, say 2dB. They also sound better at lower volume.

Awesome! Of course, this may be a custom driver, with different impedance and sensitivities than listed at Seas.

I would expect, based on the specs at Seas, that the Pulsar two would demand a new crossover, and may loose 1-2 dB of sensitivity.


However, that doesn't necessarily change the tonal balance, that's something the designer could keep more or less consistent. 

Shame I haven't heard these speakers in a very long time, but they were some of the few at shows I liked, and seem to remember liking them more than the plasma tweeter speakers too.

I think having an iconoclastic point of view really helps. At the genuine high end of speakers, I honestly think half the listeners can't hear a damn thing.

I'm not at all knocking the Pulsars, they're middle ground, high value in my mind.


I'm just saying, being your own taste master can help you save a lot of money. :)

PS - I do see enough changes to the impedance and overall sensitivity that I expect this will require nearly completely new crossovers, and slightly lower efficiencies.

Good find Prof, reading the specs on their site, the big difference I see is power handling. Long term power handling has more than doubled.

This is by no means a simple graphene coating though, as the article points out, significant changes to the voice coil and suspension have occurred, while the overall frequency response is barely touched. This makes me wonder if the graphene coating is anything more than a paint job? Their white paper mentions corrosion protection as one of the first benefits, a good thing:


http://www.seas.no/images/SEAS_Graphene_White_Paper.pdf


Also, linear travel remains the same 14mm in both, so the maximum limits are going to be similar.


From what I read here, no one should be worried their original Pulsars will be suddenly and severely upset by the new version.


OTOH, if you are Prof and looking for a deal, wait for A’goners and dealers to put the original versions on sale. :)

Now that he's updated them, before I could buy a pair of the original, I may not ever be able to afford the new higher price. Sigh....

Sit tight, Prof!! You'll see many people upgrading and selling their used one's here on A'gon.


Just keep looking and I'm sure Santa will come for you.

Best,
E

BTW, I am not of the idea that the only way to value a speaker is by driver costs.


Manufacturer reputation, and relative performance to other products in the same price range are important, as is attention to part quality in the crossover, cabinet construction, etc.


If you want to look at a speaker based on parts, I strongly and without sarcasm, suggest you DIY a pair. I do. :)


Best,
E

Judging from the :

• Driver slopes
• Impedance curves
• Off-axis response (the real killer)

The speaker JA measured did not perform differently in any meaningful way from a traditional 2nd order speaker, except for a dip in the middle of the crossover impeadance peak which is very likely an impedance compensation circuit. A nice add.

That doesn’t make it a bad speaker, at all. In fact I would say the performance is top notch for a 2-way speaker, but I see no evidence of it being more than a well designed 2-way with good drivers and traditional crossover design.

It doesn’t appear to me to be a simple second order xover,

Please explain from the data in the review.

I believe that Jeff has improved it over time.

Except that the review claims the measured speaker has their infinite slope crossover.

I read another Stereophile review of a JA speaker and it did seem to use a very high crossover slope, but only in the woofer of a 3-way. The rest seemed rather traditional.

Best,
E

If Jeff says that graphene covers the cones, then I would take that to be the truth. I have found Jeff to be an honest and forthright guy, and I believe his representations without hesitation.

Except as noted above, he's selling the Pulsar as using an exotic crossover when it really seems to be quite a common design.

I wonder if it has any effect at all? 

I mean, Magico claims it is on the cover of their Be tweeters, and now Joseph will claim it covers the Magnesium cones... how would we honestly know?? 


Remember the fake Be driver scandals?? 

Also, kind of interesting that Seas makes a lot of woofers for Magico, I wonder if this is a new OEM offering they are making?

That’s weird. Graphene is a damper? I would have assumed graphene was a stiffener.

All cones ring somewhat, metal especially, so my point was if the graphene coating reduces the ringing mode, either by damping or elevating the ringing frequency it would be useful.

I see a thread by you about that about a speaker where the woofer covers 400hz and below. Isn’t something like the Kef Reference 1 or TAD ME-1 the closest to that concept in practice--basically a 3-way coaxial?

I'm not sure what thread you are talking about, I've posted many, and I'm not the biggest proponent of WAWB speakers, but given your post, I though you might find it an interesting idea.

WAWB is a true 2-way, not a 3-way with coaxial.


The idea is to use a relatively small (3"-4") wide band driver to cover the mid-hundreds all the way up through the top octave. Takes crossovers completely out of the vocal range. You should visit DIYaudio or another site for more information on current thinking of this type of design.

Another way to think of a WAWB is a close cousin of full-range, single driver speakers, similar to the Fostex or Markaudio type of drivers.


https://www.madisoundspeakerstore.com/full-range-speaker-kits/

Let me know if you try any of them,

Erik

I think driver integration can be done well at any point, but have you tried woofer-assisted wide band? May be your cup of tea. :)


Best,
E

Hey @wildfoxinn that’s a really good catch!

You are quite right. Nothing in the FR plots, impedance or dispersion points to the claimed infinite slope. Looks like quite traditional 2nd order, with a possible impedance correction circuit thrown in for the crossover point.

I will say, besides a slightly elevated treble level, the plots are otherwise quite excellent.

My rule of thumb is 10x driver cost.


What will be interesting to me is whether or not the graphene actually matters.


Would be great to see FR and distortion plots of the raw driver with and without it.


Ideally I’d love to see graphene damp the ringing and allow for higher use of the mid-woofer.


Otherwise, it’s a marketing feature with no other value.