GR Research Speaker Upgrade Review (Sierra-2EX V2)

[R-Carpenter]

Dennis does great work.

I like Philharmonic, excellent speakers. But is it confirmed that he does not use an anechoic chamber nor an NFS in any stage of the design?

Are you going to have lower opinion of his designs if he does not use either?
I don't think he does BTW

 

[Keith_W]

Out of curiosity, how many excellent speakers, not respectable, but excellent speakers that are designed without either the use of an anechoic chamber or a Klippel NFS?

March Audio is one that I am aware of that was designed without a Klippel or an anechoic chamber, but validated with one. I know that there are ZERO Klippels in Australia. And I also know that a couple of our more respected manufacturers does his measurements the old fashioned way. He elevates his speaker on a forklift and takes dozens of measurements. Then he does a few ground plane measurement and integrates them all together with his software. One of the manufacturers is a major pro audio brand with speakers installed in dozens of cinemas. The senior engineer, a charming old gentleman who told me that his title is "senior" because "I am so old", told me that he takes his measurements in his factory. Again, with a forklift.

If you are a business, the cost of a Klippel is equivalent to hiring an employee for two years. That business needs to ask themselves whether they would rather have another employee, or whether a Klippel would save them enough time to justify the cost. If you are a small manufacturer and there are only a couple of speakers in your line-up, I think the answer is a very easy "no".

 

[NTK]

Dennis does great work.

I like Philharmonic, excellent speakers. But is it confirmed that he does not use an anechoic chamber nor an NFS in any stage of the design?

Here is a post from Dennis 2+ years ago.

I can second this. Although I can't afford the Klippel asking price, I now send any new model off for a 3rd-party Klippel test to see whether I've messed up. That said, I've also found that very careful outdoor tests with quasi-anechoic measurement software and a properly conducted and and spliced ground plane measurement can come remarkably close to the Klippel measurements. However, winter is closing in and I think I'll continue to ship my designs off to Amir or Erin.

 

[PristineSound]

By your own standard, if the speaker is not measured using Klippel or brought in anechoic chamber, it is not excellent or substandard.

I have not said speakers designed without an anechoic chamber or an NFS can't be excellent, in fact, I'm would like to know which speakers were designed without and how many. I can tell you all the excellent speakers that I know of from days past to present all either were designed using an anechoic chamber or the NFS.

But Klippel wasn't there before 2010 and anechoic chambers are not dime a dozen.
"controlled directivity, low distortion, absence of resonance, bass extension, SPL" All these parameters can be measured using gated MLS. Usually, speakers with flat on axis response, smooth falling off axis response, low distortion at high SPL capabilities (high performance driver units) and good low end extension tend to sound very good or excellent.
Do you think your two way design can sound as life-like as ProAc 4? I am not a fanboy of ProAc btw. It's just one of the designs that I liked.

And hence, I'm trying to figure out how many of them exist.

 

[PristineSound]

March Audio is one that I am aware of that was designed without a Klippel or an anechoic chamber, but validated with one.

Then it's disqualified. Validation is still part of the design.

Many small shops will use ground plane, or quasi anechoic to design, once they feel comfortable they will send it in to an anechoic chamber or an NFS for measurements, they have their fingers crossed that it comes back fairly accurate to when they measured as it's $2k or more per measurement. Many small shops will send it in few times to get measured.

 

[PristineSound]

Are you going to have lower opinion of his designs if he does not use either?
I don't think he does BTW

Absolutely not. But I will say this, when I was shopping for new speakers about an year ago, I was between Philharmonics and Ascend, I ultimately went with Ascend because (1) they published a full blown spin with polar graphs (2) they also publish cabinet resonance data on their bamboo cabinets.

 

[R-Carpenter]

Many small shops will use ground plane, or quasi anechoic to design, once they feel comfortable they will send it in to an anechoic chamber or an NFS for measurements, they have their fingers crossed that it comes back fairly accurate to when they measured as it's $2k or more per measurement. Many small shops will send it in few times to get measured.
es back fairly accurate to when they measured as it's $2k or more per measured

How do you know that? Have you been to many small shops? If it's $2k or more to measure the speaker with NFS, I'd opt out. I don't know many people who purchase the speakers strictly based on NFS posted data. Majority of consumers don't know how to interpret it anyway. And high price consumers don't care about measurements. There are other purchasing decision making triggers.

Absolutely not. But I will say this, when I was shopping for new speakers about an year ago, I was between Philharmonics and Ascend, I ultimately went with Ascend because (1) they published a full blown spin with polar graphs (2) they also publish cabinet resonance data on their bamboo cabinets.

Out of curiosity, which Philharmonic? Have you listened to both systems or just went based of posted measurements?
You do know that cabinet resonances show up on impedance graph?

 

[Keith_W]

Then it's disqualified. Validation is still part of the design.

Umm, it was a finished, commercially available speaker by the time Erin measured it. It's a bit like me throwing together a speaker. If Erin measures it a few years later, it's disqualified?

 

[diddley]

What is the basis for your claim? If you are disciplined, you do not need a Klippel. Many DiYers (along with yours truly) do spins that are much higher quality than Danny's work. For the Directiva project, we did have Amir's Klippel support, but it was mainly as a validation step. Danny's results based on his measurements are hit or miss. Amir has already articulated some of his major process flaws. Would be interesting to know whether his results are poor application of measurement gear or something else.

He doesn't have the intellectual skills for it, remember; "5 hours I ain't got time for this, now don't waist my time". that was his response regarding the klippel.

 

[René - Acculution.com]

Would it of interest to model the pressure phase with and without the filter that Danny has applied to modify the electrical phase? If someone gives me T/S parameters for a similar tweeter, perhaps a sketch of its geometry, a passive crossover with component values, and then the LCR topology that Danny mentions and some appropriate component values, I can probably put it together. Danny clearly mixed up these two phases, so perhaps it could be interesting to compare the two.

 

[RickS]

Would it of interest to model the pressure phase with and without the filter that Danny has applied to modify the electrical phase? If someone gives me T/S parameters for a similar tweeter, perhaps a sketch of its geometry, a passive crossover with component values, and then the LCR topology that Danny mentions and some appropriate component values, I can probably put it together. Danny clearly mixed up these two phases, so perhaps it could be interesting to compare the two.

Hi Rene!

Might be interesting but not sure is worthy of your time. Raal has already stated the lower cross would be problematic.

Thanks for offering though.

 

[René - Acculution.com]

Hi Rene!

Might be interesting but not sure is worthy of your time. Raal has already stated the lower cross would be problematic.

Thanks for offering though.

Sure thing. Perhaps it could be interesting in a more general sense via a separate post called "Electrical phase vs acoustics phase" or something like that.

 

[mj30250]

The raw response of the ribbon was posted upthread. Danny's lower crossover is really pushing if not taking the tweeter beyond the limits of the designed passband.

 

[Postlan]

This is a total amateur mod. Looking strictly at the frequency response, quite a few audiophiles prefer a combination of a BBC dip and boosted highs like you see in B&W speakers, so they probably thought this was better. But with this much added distortion, it’s not even a matter of personal preference anymore...

 

[Raj21p]

This is exactly why context matters with crossover “upgrades.” On already well-engineered speakers like the Sierra-2EX V2, it’s very easy to trade one tiny perceived issue for multiple measurable compromises elsewhere, especially in directivity and tweeter stress. I’m not against mods in general, but personally I think once a design has been heavily optimized with Klippel-level measurements, the gains from aftermarket crossover changes become very questionable.

 

[amirm]

Question was raised regarding the waterfall. Here are the two measurements:

I only see tiny differences which naturally arise from small differences in frequency response. This is backed by the fact that cabinet and driver resonances would be there regardless. There is a tiny bit of reduction of the 1.3 kHz but that is due to lower level there which is an error to begin with.

 

[RickS]

Fyi, moved some recent general posts about speaker design to more appropriate thread to keep this thread more specific to the upgrade review.

 

[GPJ]

BTW, these are the published measurements on Ascend's website:

I have to think he did not bother to even look at them. As otherwise, anyone would conclude that there was nothing there to fix.

well ya know Amir, you're really offending the "if it ain't broke, fix it til it's broke" crowd ...............