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

[kimmosto]

This isn't a knock on some casual DIYer's and their use of CLIO and a Dayton EMM-6 mic but facts are facts, whether your feelings are hurt or not:

Where did you pick EMM-6. CLIO has own calibrated mics, and system supports any mic. For example Earthworks Audio M30.

the most accurate speaker measurement method/tool is the NFS or a proper anechoic chamber (the larger the better), full stop.

Method is actually quasi anechoic. Result is mathematical construction of multiple measurements close to DUT. Measurements on ASR and EAC don't look very plausible. Either operator or the system fails, but complex indirect method has made that possible. For example, perfectly symmetrical constructions have given quite totally different results in horizontal plane to left and right. Responses to equal absolute angles can have 1-3 dB differences, and peaks and dips look quite random. In addition, resolution of CTA-2034 directivity is specified as 10 ppo.
Directivity / directivity index is wrong at low frequencies when there is a port or passive radiator on the back. Error has been 2-3 dB which is not acceptable for designing directive LF radiators with multiple radiators. Of course low SNR at high pass slope is one probable problem, but that is not good excuse to publish systematically wrong data below 50-60 Hz.

Now back to Danny, he's got to be so stupid to allude to the CLIO as some sort of standard bearer and somehow it's adequate to be used for his purpose.

It's already told that bad design is totally on Danny. Not measurement gear for sure. Other problems with construction are possible too, but let's trust manufacturing this time. I just wonder why mod V1 was measured while V2 had been available for almost two months before this review. Intentional collective harassment, kicking and punishment without any changes to make correction after manufacturer's notice. Very adult and respectable - NOOT.

 

[a4eaudio]

...If it's going to hurt some feelings ...

I doubt anyone's feelings are hurt by you sharing your opinions.

... Is there something wrong with a $60 Dayton mic for the purpose of high precision speaker measurement? Stupid question, of course there is...

But no one asked this question. Is there something wrong with using a $60 Dayton mic to change my tire? Stupid question, of course there is. KEF should not be using a Dayton mic. Even though the Klippel NFS does not come with a set mic, it wouldn't make much sense to use a Dayton mic. The point was...for what Danny is doing...tweaking a passive crossover in a two way speaker with a crossover around 2-3kHz, you don't need more than a Dayton mic with a good calibration file, a decent 2-in, 2-out audio interface, and REW. It was a correct statement then and it is a correct statement now.

...the most accurate speaker measurement method/tool is the NFS or a proper anechoic chamber (the larger the better), full stop....

Again, you need to understand your tools and there uses. (1) An anechoic chamber is not a measurement tool, it doesn't actually take measurements, its just a room. (2) An anechoic chamber is about the WORSE tool if you care about measuring below 200Hz. I can do better with a Dayton IMM-6 connected to my phone in my garage. Ground plane is probably the best for 200Hz and below.

...But today, the NFS is a fully automated robotic arm, you set it up, click the go button and walk away for few hours and you come back with high resolution, high precision results. It makes iterations easy and reliable...

YES!! This, is the advantage of the NFS.

 

[a4eaudio]

Where did you pick EMM-6...

Haha, sorry, that is my fault!
I made the point earlier that it is not Danny's tools (Clio) but his methodology and said that even a Dayton EMM-6 was fine for what he was doing.

 

[R-Carpenter]

Since I'm already on a roll hurting feelings, I might as well keep going.

Speakers as a collective whole from just a decade ago compared to speakers of today has a noticeable objective performance gap.

The best speakers of yesterday were all designed using an anechoic chamber.

I believe the gap between the performance of speakers from yesterday and today is largely due to the tooling. The best method of yesterday was an anechoic chamber, but it was super laborious. You had to manually position the mic for each measurement. Then you have to wait for a day of moderate temperature, humidity and wind to take the speaker outside to measure the bass on a 20-30 foot pole and then stitch it together with the initials anechoic measurements. Maybe some had custom toolings that would reduce the time and effort in measuring speakers.

I once tried to do a quasi-anechoic measurement manually just to go through the experience, it was such a waste of my time and never attempted it again, my time is way too valuable for this ancient practice. It's akin to my most recent experience with coding and debugging without having AI to support you.

But today, the NFS is a fully automated robotic arm, you set it up, click the go button and walk away for few hours and you come back with high resolution, high precision results. It makes iterations easy and reliable. Other tools like the Dynaduio Jupiter enables faster measurements as well.

Not sure who's feelings you are hurting.
Most speaker manufacturers do not have access to anechoic chamber, never did and designed the speakers based on MLS technology that became more and more affordable to DIY crowd now days. Do you remember how much MLSSA costed then it first came out?

There's hardly any gap in a performance. in the last 15 years. Klippel became available in 2010s or so. Major improvements in the speaker design happen because of improvements in driver design and semi anechoic measurements. Klippel takes this a couple of notches up but it will be surpassed buy something else. May be Chinese will have a drone with mic flying around the speaker and measuring 10 million points. Whatever you using for measurements, you are still designing within driver limitations and the design in the thread was less than optimal to begin with (even tho the designer had an access to klippel) and granted, it was screwed up by Danny even more. Both of these events took place to make a dime. It is BTW very possible that Danny "designed" the upgrade because one of the customers of Sierra didn't like the sound and send it to him. I had people coming to me with requests to improve crossovers from time to time or just measure and see if anything can be improved. I even had someone bringing GR-research speakers in for testing a few years ago. These were actually quite good.

You can use whatever tools you want. The objective is to have a good speaker and a good product if you are a commercial manufacturer. But it's you as a designer who is using the tools. If in your case klippel pays off, fantastic! It's a very pricey system.

As far as your dig at dayton mm6 mic, what do you think the limitations are if it's calibrated, let's say in comparison to calibrated Earthworks M30?

 

[PristineSound]

The point was...for what Danny is doing...tweaking a passive crossover in a two way speaker with a crossover around 2-3kHz, you don't need more than a Dayton mic with a good calibration file, a decent 2-in, 2-out audio interface, and REW. It was a correct statement then and it is a correct statement now.

Against the risk of sounding like a broken record arguing against an opinion that isn't even related to the points that I've made at the onset, and with little diligence nevertheless, there is no need for a reply here. Everything that I needed to say was said.


Except I will reply to this:

Again, you need to understand your tools and there uses. (1) An anechoic chamber is not a measurement tool, it doesn't actually take measurements, its just a room. (2) An anechoic chamber is about the WORSE tool if you care about measuring below 200Hz. I can do better with a Dayton IMM-6 connected to my phone in my garage. Ground plane is probably the best for 200Hz and below.

Where did I said that an anechoic chamber is a "measurement tool"? Can you screenshot it for me?

I said an anechoic chamber is a tool and according to the Merriam-Webster dictionary, here is a definition of the word "tool":

Is an anechoic chamber a thing? The answer is yes.

Is an anechoic chamber used in performing an operation in a profession? The answer is yes.

So is an anechoic chamber a tool? The answer is also a yes.

And yes, I am aware of the bass limitations of an anechoic chamber, hence I said this:

Then you have to wait for a day of moderate temperature, humidity and wind to take the speaker outside to measure the bass on a 20-30 foot pole and then stitch it together with the initials anechoic measurements.

the most accurate speaker measurement method/tool is the NFS or a proper anechoic chamber (the larger the better), full stop.

I am always very careful in choosing my words, especially when engaging with people on internet as evident here.

 

[PristineSound]

There's hardly any gap in a performance. in the last 15 years.

Are you referring to as a collective whole the objective performance of speakers from about 15 years ago does not have much of a performance gap with the most recent speakers, say from few years ago?

If that is what you are referring to, then I vehemently disagree.

Klippel became available in 2010s or so. Major improvements in the speaker design happen because of improvements in driver design and semi anechoic measurements.

Right on topic, since we are on this thread, Dave from Ascend Acoustics, will argue with that. Yes, better drivers is a big part of the equation, but driver, cabinet and crossover integration that ultimately makes an entire system, that is tooling. Dave once said on his forum, it would have been near impossible to get the directivity that he is able to achieve, especially without the use of a waveguide, without the NFS.

I think I take Dave's word.

EDIT: I also want to add that time is the only reliable function of technological advancement. And that technological advancement will always yield a better result in anything and everything. In other words, when it comes to technological advancements, the future will always win. . .period, full stop, end of story.

This implicitly and explicitly implies that speaker performance will always be better in the future as evident that the speakers of today are hands down better than the speakers of yesterday. We can take this to the bank.

 

[Everett T]

Not sure who's feelings you are hurting.
Most speaker manufacturers do not have access to anechoic chamber, never did and designed the speakers based on MLS technology that became more and more affordable to DIY crowd now days. Do you remember how much MLSSA costed then it first came out?

There's hardly any gap in a performance. in the last 15 years. Klippel became available in 2010s or so. Major improvements in the speaker design happen because of improvements in driver design and semi anechoic measurements. Klippel takes this a couple of notches up but it will be surpassed buy something else. May be Chinese will have a drone with mic flying around the speaker and measuring 10 million points. Whatever you using for measurements, you are still designing within driver limitations and the design in the thread was less than optimal to begin with (even tho the designer had an access to klippel) and granted, it was screwed up by Danny even more. Both of these events took place to make a dime. It is BTW very possible that Danny "designed" the upgrade because one of the customers of Sierra didn't like the sound and send it to him. I had people coming to me with requests to improve crossovers from time to time or just measure and see if anything can be improved. I even had someone bringing GR-research speakers in for testing a few years ago. These were actually quite good.

You can use whatever tools you want. The objective is to have a good speaker and a good product if you are a commercial manufacturer. But it's you as a designer who is using the tools. If in your case klippel pays off, fantastic! It's a very pricey system.

As far as your dig at dayton mm6 mic, what do you think the limitations are if it's calibrated, let's say in comparison to calibrated Earthworks M30?

What do you think was wrong with Ascend's design?

As for Dayton mic compared to the Earthworks, the Dayton isn't useful below 20hz and can't handle very high SPL. There is nothing wrong with the Dayton when used within its intended limits.

 

[dfuller]

It is also a mystery to me how commercial speaker companies are able to put out mediocre designs, having access to funds and top notch tooling.

It's not a mystery to me at all. To be profitable in the traditional paradigm (i.e. with a dealer), your material and assembly costs must be way lower than your pricing to dealers - so usually a pretty small margin of actual MAP (minimum advertised price) actually goes into the speaker itself.

When you're building for a given price point, your maneuvering room gets pretty small. You have to make compromises somewhere - be that distortion, build quality, driver quality, how many crossover components you can use, the quality of those components, how many prototypes you can make, etc etc.

Measurements on ASR and EAC don't look very plausible. Either operator or the system fails, but complex indirect method has made that possible. For example, perfectly symmetrical constructions have given quite totally different results in horizontal plane to left and right. Responses to equal absolute angles can have 1-3 dB differences, and peaks and dips look quite random. In addition, resolution of CTA-2034 directivity is specified as 1/10 ppo.
Directivity / directivity index is wrong at low frequencies when there is a port or passive radiator on the back. Error has been 2-3 dB which is not acceptable for designing directive LF radiators with multiple radiators. Of course low SNR at high pass slope is one probable problem, but that is not good excuse to publish systematically wrong data below 50-60 Hz.

The comparisons I have seen match to traditional measurements pretty damn well. It's not perfect, but nothing is.

It's already told that bad design is totally on Danny. Not measurement gear for sure. Other problems with construction are possible too, but let's trust manufacturing this time. I just wonder why mod V1 was measured while V2 had been available for almost two months before this review. Intentional collective harassment, kicking and punishment without any changes to make correction after manufacturer's notice. Very adult and respectable - NOOT.

Couple reasons.

1. V1 was the one sent, I believe by Dave from Ascend...

2. V2 barely does anything different from the original XO, so what would the point even be?

 

[R-Carpenter]

What do you think was wrong with Ascend's design?

As for Dayton mic compared to the Earthworks, the Dayton isn't useful below 20hz and can handle very high SPL. There is nothing wrong with the Dayton when used within its intended limits.

If I were to redesign this speaker, I would either use more robust tweeter or add a mid-range in the mix. You could also load tweeter in the waveguide. I mentioned this before. I don't think existing design is "wrong" but it's pulling itself by the hair from the swamp. As stated, commercial guys have different limitations and objectives from an individual.

I agree with you about Daytom mic 100% and I am not the one who was criticizing it. mm6 can't handle high SPL which in near field you can get to pretty quickly. M30 can handle higher SPL and there's also M50 if needed. I personally use M30 but if I had mm6, it is totally fine for measurements, crossover design etc.

 

[amirm]

As far as your dig at dayton mm6 mic, what do you think the limitations are if it's calibrated, let's say in comparison to calibrated Earthworks M30?

Logivity, distortion, max SPL

 

[amirm]

It's already told that bad design is totally on Danny. Not measurement gear for sure.

A major point of contention is distortion. You sure you can make trustworthy distortion measurement with his gear? And why is his gear showing reduced treble response?

 

[amirm]

For example, perfectly symmetrical constructions have given quite totally different results in horizontal plane to left and right.

Totally different??? And how do you know the construction is perfectly symmetrical?

 

[PristineSound]

You can use whatever tools you want. The objective is to have a good speaker and a good product if you are a commercial manufacturer. But it's you as a designer who is using the tools. If in your case klippel pays off, fantastic! It's a very pricey system.

Better tools = better results.

High price doesn't always mean better, but better is never cheap.

As far as your dig at dayton mm6 mic, what do you think the limitations are if it's calibrated, let's say in comparison to calibrated Earthworks M30?

I defer to Amir's response. But I also want to add that better mics also have a more reliable measurements above 10–15 kHz as well.

Not sure what mic Danny uses but if he was using a cheap mic, that could be the reason why his high frequency measurement seems to be off. Not sure.

 

[dfuller]

Not sure what mic Danny uses but if he was using a cheap mic, that could be the reason why his high frequency measurement seems to be off. Not sure.

Plausible, for sure. Personally my money is on the smoothing doing weird things (depending on the exact algorithm you use, different response variations pop out), but that's just me. Idk. There's a laundry list of things done wrong, and it's certainly possible that an improperly calibrated mic is part of it.

 

[a4eaudio]

...Where did I said that an anechoic chamber is a "measurement tool"? Can you screenshot it for me?

Ummm...okay

 

[PristineSound]

Ummm...okay

View attachment 531411

You read it wrong.

You read it as: measurement (method/tool)

Try this: (measurement method)/(tool)

 

[a4eaudio]

....As for Dayton mic compared to the Earthworks, the Dayton isn't useful below 20hz and can't handle very high SPL. There is nothing wrong with the Dayton when used within its intended limits.

Exactly. That was my point...every time I referred to the Dayon EMM-6 I tried to caveat it with what Danny is doing here....because his tools were being blamed...that for a xo mod of a two way with a xo around 2-3kHz even a Dayton EMM-6 would be fine. The Dayton isn't useful below 20Hz, or at high SPL levels, and it has HIGH self noise and is not reliable for distortion measurements. [It is not relevant to the points being made in this thread, but full disclosure - I use an Earthworks microphone exactly because of those limitations.]

 

[RickS]

As I review the thread, see the discussion over Danny's speaker measurement equipment is on continuous replay. This is despite the fact that several have admitted it is sufficient and Danny's problems are in his implementation. There are at least 2 other threads here that are more appropriate for those who feel a need to continue to discuss. I am willing to move any relevant posts if desired.

Please move on. Thanks!

 

[dfuller]

I am wondering, though, why he pretty much always insists on moving Fc down. That doesn't always have benefits, and it gets pretty messy with some tweeters.

 

[Dave Bullet]

The irony for me is how Danny treats other manufacturers, not just with objective criticism (measurements) but slurs and subjective judgement of intelligence or ethics yet cannot handle reviews of his own products.

I remember a time where zaph audio tested Danny's own MR driver range. The cheapest at the time was used in many of Danny's speakers. The results were pulled down very quickly when Danny had a go at zaph for publishing them.

Danny also has a problem with cast alloy baskets so prefers his plastic frames. Something to do with ringing that he's never been able to demonstrate