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Audio First Fidelia on Erin’s Audio Corner

But careful nearfield + farfield splicing, ground plane measurements or Klippel NFS can get you 99% (made up number) what you need.
But for those that neither have a Klippel NFS nor an anechoic chamber, they can send them to third parties that do.
Of course. My main point was to dispel the assumption some may have that a Klippel is the *only* way to measure a speaker anechoically and that any company who has not purchased one does not do measurements (and that maybe no manufacturer in the UK does measurements).

There are in fact videos of anechoic chamber testing at the KEF and B&W factories and KEF even ships their high end speakers with a printed anechoic FR plot from the exact pair of speakers you order. Audiofirstdesigns could probably even speak to this given his experience there.
 
That have worked but.. researches show that most people tend to prefer accuracy.... The numbers of brands that espouse that, are is growing, and not the usual Hi-Fi ones.. among these , Apple, SONOS, etc are blazing a different and successful trail.

Peace
I see this trend also and it is positive.
 
Any serious speaker designer (e.g. KEF, B&W) have an anechoic chamber for testing. Klippel's fine if you are testing in your garage like Erin...

Woah dude that is quite the claim. Klippel systems are used by serious speaker companies around the world.

 
B&W Loudspeakers Ltd., UK

I assume they just never unboxed it based off the junk they put out.

If you already built your chamber on company grounds years ago you use that :)

Allegedly the klippel system is atleast just as good and possibly better than the smaller chambers ? And then it’s not expensive at all compared to a very big empty building filled with sound deadening contraptions .

So I get the appeal you can do it automated in a spare room or ( or garage or shed if your a one person business:) )

I can share a little regarding these topics as an industry insider, but I won't go too deep.

B&W put a lot of resources into research, if I remember correctly, at their new office in Southwater they have like 3 or 4 anechoic chambers, and I believe they have Klippel equipment for driver measurements like most of the big brands. And from available data, you can tell their drivers are actually pretty good. B&W has a big R&D team but every engineer only deals with one type of thing, and there is a small team of people who decide what the final tuning/response should be. Based on the outcome, you can tell It's just that they don't agree with the Harman group / Dr. Floyd Toole's philosophy in terms of loudspeaker system design, it is probably more about some business decisions, the sound signature they want to maintain etc, and it has worked for them, for many years, so I don't see why they would change it dramatically even they can easily do. (Quite a few B&W engineers are ex-KEF engineers and I got contacted by the B&W recruitment team twice as well so I know a bit about them...)

In my opinion, a Klippel NFS has a lot of advantages over the traditional anechoic chambers (especially the small ones), but one also has to be careful about it as errors can happen due to measurement setup mistakes. The practical problem with anechoic chambers is that, usually, they are not big enough. You will run into the chamber cut-off / remaining room modes and you still have to find some other way to measure the real LF response / polar of the speaker and merge it with the chamber data. Many small chambers have issues starting from 2-300 hz, and depending on the size of the speaker that can be where the baffle step response starts. Near-field measurement is not the best solution here as it can't capture the baffle step. Another problem one often encounters is that, for a big floor stander with multiple woofers, you can't get the true far-field response by measuring it at 1m in a small chamber. For all these issues you usually need a huge space or go outdoors to sort things out.

And if you wanna measurement the polar response of a driver, or design an in-wall speaker system, you either build a 2pi anechoic chamber (rare to see, usually owned by driver OEM company, Tymphany UK has the biggest one in Europe, and it is impressive) or you find a big open space and dig a hole for the speaker on the ground to do the measurement. For the latter one, I have good memories of trying to save the speaker and all the measurement equipment with my comrades under a sudden rain (UK ain't it).

The NFS, if used carefully, can deal with all the issues above and make one's life a lot easier, and a lot cheaper than building a big anechoic chamber.
 
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I look forward to seeing your business develop, I firmly believe measurement led is he way ahead.
Keith
 
I look forward to seeing your business develop, I firmly believe measurement led is he way ahead.
Keith

All manufacturers are measurement led, or can you point out one brand that doesn't use any type of measurement during the development of their loudspeakers.

As @Audiofirstdesigns pointed out, the deviation that can be seen in for B&W and other brands are most often there because of the voicing. Not everyone strictly follows Harman’s conclusions.

I think we can assume that all mid-size to large-size loudspeaker manufacturers who don't have a Klippel Near Field Scanner don’t feel the need for it, as they already have a sufficient suit of measurement devices and/or anechoic chambers that already covers what is needed to be covered.
It's likely small potatoes for a company like B&W to invest in a NFS if they thought they needed one.

I don't know how fast a Klippel NFS can be set up for one single specific task during the development, but it may be faster to just set up a microphone for most single development tasks.
 
As @Audiofirstdesigns pointed out, the deviation that can be seen in for B&W and other brands are most often there because of the voicing. Not everyone strictly follows Harman’s conclusions.
I agree. I think it’s a good thing that manufacturers have their own house sound/curve. Otherwise consumer choice will be too bland. The important part, as I see it, is the measurements movement highlighting the importance of dispersion control in multi-way designs. With good dispersion, a house curve makes sense and will translate well from room to room and take EQ well. I suspect that EQing a system has always had a hit and miss following with audiophiles because of the common instance where it is applied to speakers with poor dispersion control.

What will also be interesting is whether any mainstream speaker manufacturers add cardioid radiation to their products.
 
1000068503.jpg

Work in progress...
It takes a long time to unpack. Most of the metal parts are wrapped tightly with cling film which took quite a lot of effort to unwrap. One suppose to bolt the NFS to the floor but I can't do this at my office so I learnt from Erin and cut a large piece of 18mm MDF to be the base.

1000068508.jpg

More accessories in the boxes.

1000068512.jpg

Finished the base part. And I am off to my holiday now... have a good one guys!

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… and you!
 
That is a cool Christmas present.
Keith
 
View attachment 416211
Work in progress...
It takes a long time to unpack. Most of the metal parts are wrapped tightly with cling film which took quite a lot of effort to unwrap. One suppose to bolt the NFS to the floor but I can't do this at my office so I learnt from Erin and cut a large piece of 18mm MDF to be the base.

View attachment 416213
More accessories in the boxes.

View attachment 416223
Finished the base part. And I am off to my holiday now... have a good one guys!

View attachment 416226
Happy holidays and looking forward to what the nfs brings in the future…
 
Came back today and carried on building this big and noisy spinning metal boy again :D

1735347214035.png


Got it mounted on the MDF base and moved it to a suitable position. But quickly I found that the computer desk had to go (to somewhere else) as its corner was just within the spinning radius. I also need to get a small rack for the Klippel analyser and the amplifier...

1735347417175.png


Took a while to get the metal pole leveled.

1735347610492.png


This is the arm.

1735347756347.png


The boy is now armed!

Looking at the remaining two thousand bags of parts it seems like I need one more day to get it spinning... Time to bed.
 
Looking at the remaining two thousand bags of parts it seems like I need one more day to get it spinning... Time to bed.
Definitely more bags of bits than the Lego sets my son got for Christmas!

Couple of questions about the NFS:
1. What’s the minimum room size for them?
2. How do they calculate an anechoic response at low frequencies? Does it do some kind of averaging so that the room modes cancel out, or does it work out what the room modes are and add a corrective curve to the measured response?
Thanks.
 
You would definitely need to know minimum room size before commencing!
Keith
 
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Definitely more bags of bits than the Lego sets my son got for Christmas!

Couple of questions about the NFS:
1. What’s the minimum room size for them?
They provide room minimum size:
1735407882277.png


2. How do they calculate an anechoic response at low frequencies? Does it do some kind of averaging so that the room modes cancel out, or does it work out what the room modes are and add a corrective curve to the measured response?
Thanks.
Sound Field Separation (SFS). Since the speaker is stationary in-room, they have constant room interaction and can use the changing mic position to calculate anechoic bass response. @NTK has a discussion here with comments on a couple methods, and how Klippel may be approaching the problem:
Plus a complete discussion of two ways to handle field separation of the low frequency part:

Amir has some discussion about optimizing low frequency measurements for large speakers with multiple bass elements:

edit:
added excellent DIY 3D scanner link
fixed the link to the Klippel pdf
 
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They provide room minimum size:
View attachment 416966


Sound Field Separation (SFS). Since the speaker is stationary in-room, they have constant room interaction and can use the changing mic position to calculate anechoic bass response. @NTK has a discussion here with comments on a couple methods, and how Klippel may be approaching the problem:
Plus a complete discussion of two ways to handle field separation of the low frequency part:

Amir has some discussion about optimizing low frequency measurements for large speakers with multiple bass elements:

edit:
added excellent DIY 3D scanner link
fixed the link to the Klippel pdf
Many thanks for posting these links. Appreciate it.
 
Came back today and carried on building this big and noisy spinning metal boy again :D

View attachment 416858

Got it mounted on the MDF base and moved it to a suitable position. But quickly I found that the computer desk had to go (to somewhere else) as its corner was just within the spinning radius. I also need to get a small rack for the Klippel analyser and the amplifier...

View attachment 416859

Took a while to get the metal pole leveled.

View attachment 416862

This is the arm.

View attachment 416864

The boy is now armed!

Looking at the remaining two thousand bags of parts it seems like I need one more day to get it spinning... Time to bed.
Is your flooring carpeted? If it is carpeted, maybe look into placing some sandbags or plate weights on the MDF to try to compress that carpet and minimize any rocking when the Klippel arm is rotating. It goes without saying that I don’t have a Klippel, but I have to believe any rocking would be detrimental in more ways than one. Looks like a fun project!
 
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