High-resolution Speaker Frequency Response & Distortion Measurements and Why We Need Them (video)

[tomtoo]

From the Quad ESL-63 courtesy of Stereophile. 1 khz squarewave microphone capture.

Quad ESL-63 loudspeaker Measurements

Sidebar 2: Measurements (from June 1989, Vol.12 No.6) As I had dragged my motley collection of test equipment (footnote 1) over to Larry Archibald's listening room to carry out a set of measurements on the Mirage M1 loudspeaker he has reviewed elsewhere in this issue, I thought it might be a...

www.stereophile.com

Nice impulse result too.

942 hz squarewave from a DIY horn speaker by B. Walso (of Liberty software that wrote Diffmaker).

That cant be the a acustic output of a square wave on a speaker.So what is it?

 

[Music1969]

Who is the company rep that prompted this video ?

Or just a link to their comment

 

[Music1969]

The two papers by Angelo Farina describing the swept sine technique mentioned in @amirm's video:

Simultaneous Measurement Of Impulse Response And Distortion With A Swept-Sine Technique - Angelo Farina

Advancements in Impulse Response Measurements by Sine Sweeps - Angelo Farina

He's a smart guy and very nice guy.

He makes a cool free multichannel FIR filter convolver and helped me with some issues using it

 

[tomtoo]

We are far far out of high resolution on speaker. Capture a square wave from the drivers, nobody will know it is a square wave.

If you think just for a moment, than you see why a speaker cant do a square wave. A speaker can only do what you see in the step responce. What is a square wave without the off. Square waves you can do with electronic but not with speakers. If you give lets say 2V to a speaker, then it goes to,this position. And there it stays and does not produce any acustic signal. So how the speaker should produce the top of the square? Right it just cant do. Keep square waves in the electronic department.

 

[kongwee]

If you think just for a moment, than you see why a speaker cant do a square wave. A speaker can only do what you see in the step responce. What is a square wave without the off. Square waves you can do with electronic but not with speakers. If you give lets say 2V to a speaker, then it goes to,this position. And there it stays and does not produce any acustic signal. So how the speaker should produce the top of the square? Right it just cant do. Keep square waves in the electronic department.

As far as I can remember driver movement along to voltage or current. If you apply dc current, it will move to positive position. Off it will back to it's neutral position. Reverse polarity will move to opposite direction. In ideal scenario it will move in infinite speed and produce a square wave. Do it 30 cycle per second, you are creating sound that you can heard. In reality, the diaphragm will take time to move in or out. lt is far off.

Like this diagram if 0.5 replace by 80db. the dB difference is something if this is legal scientifically.

 

[tomtoo]

As far as I can remember driver movement along to voltage or current. If you apply dc current, it will move to positive position. Off it will back to it's neutral position. Reverse polarity will move to opposite direction. In ideal scenario it will move in infinite speed and produce a square wave. Do it 30 cycle per second, you are creating sound that you can heard. In reality, the diaphragm will take time to move in or out. lt is far off.

Like this diagram if 0.5 replace by 80db. the dB difference is something if this is legal scientifically.
View attachment 216030

What you see is how the driver swings around its .5v position. Couse it wont stop there imediatly. A ideal driver wont do this and the acustic output would be zero.With DC a driver cant produce acoustic output. For acustic output you need to move air. Thats why drivers cant produce a rectangle wave. Or in other words if you see there something like a rectangle its the bad behaviour of the driver. So thats why you cant replace Voltage with dB. If you would measure the movement of the driver with a laser than you could replace the Volt with mm. But when it has reached top level it stops moving, your db's are 0. You can not go from the electronic signal world 1 to 1 into the acustic world.

 

[markanini]

Would be the the only time high-res makes a difference, because of inter-modulation distortion. If it's audible that's another case of audiophiles liking distortion again.

Or just down sample to 44100 or 48000 and enjoy distortion-free audio.

 

[kongwee]

What you see is how the driver swings around its .5v position. Couse it wont stop there imediatly. A ideal driver wont do this and the acustic output would be zero.With DC a driver cant produce acoustic output. For acustic output you need to move air. Thats why drivers cant produce a rectangle wave. Or in other words if you see there something like a rectangle its the bad behaviour of the driver. So thats why you cant replace Voltage with dB. If you would measure the movement of the driver with a laser than you could replace the Volt with mm. But when it has reached top level it stops moving, your db's are 0. You can not go from the electronic signal world 1 to 1 into the acustic world.

Ok I get it. Have to look a the movement of the driver. Is there is any measuring tools that does it?

 

[tomtoo]

Ok I get it. Have to look a the movement of the driver. Is there is any measuring tools that does it?

Not sure if i get you. But there are laser presicion meters to measure the movement of drivers.

Laser

Direct measurement of the mechanical vibration becomes almost as important as acoustical measurements.

www.klippel.de

 

[kongwee]

Not sure if i get you. But there are laser presicion meters to measure the movement of drivers.

Laser

Direct measurement of the mechanical vibration becomes almost as important as acoustical measurements.

www.klippel.de

Anybody use this for review?

 

[tomtoo]

Anybody use this for review?

No. Thats more for driver designers.

 

[Fidji]

Finally, I know now, which smoothing is used in this measurements .
REW here we go ….

 

[Katji]

Not sure if i get you. But there are laser presicion meters to measure the movement of drivers.

Laser

Direct measurement of the mechanical vibration becomes almost as important as acoustical measurements.

www.klippel.de

[ I noticed some interesting things on klippel.de - uBlock found nothing, 0. And the languages available. ]

 

[Katji]

...hmmm...People ask for things to be included in speaker reviews...

If I consider buying some speakers/drivers, I will check the Klippel user list to find out if the manufacturer uses Klippel. If not, no buy.
.....It is 2022 now.

 

[tomtoo]

...hmmm...People ask for things to be included in speaker reviews...

If I consider buying some speakers/drivers, I will check the Klippel user list to find out if the manufacturer uses Klippel. If not, no buy.
.....It is 2022 now.

I think you can build good speakers without a klippel nfs. But it makes things more easy. And if you look just at drivers, than i think many use a klippel system somehow.

 

[DWI]

From the Quad ESL-63 courtesy of Stereophile. 1 khz squarewave microphone capture.

Quad ESL-63 loudspeaker Measurements

Sidebar 2: Measurements (from June 1989, Vol.12 No.6) As I had dragged my motley collection of test equipment (footnote 1) over to Larry Archibald's listening room to carry out a set of measurements on the Mirage M1 loudspeaker he has reviewed elsewhere in this issue, I thought it might be a...

www.stereophile.com

Nice impulse result too.

942 hz squarewave from a DIY horn speaker by B. Walso (of Liberty software that wrote Diffmaker).

Having owned a pair of ESL63 rebuilt by Quad, they make measurements pointless. They don’t go loud and they don’t go deep, but for classical and jazz they beat anything for pure musical pleasure. They are also big and ugly and my wife forced a sale.

 

[DWI]

...hmmm...People ask for things to be included in speaker reviews...

If I consider buying some speakers/drivers, I will check the Klippel user list to find out if the manufacturer uses Klippel. If not, no buy.
.....It is 2022 now.

There is a Klippel customer list, but Amir insists that the users of NFS are not disclosed, even though some describe using it. Klippel describe it as a tool to dramatically speed up the design process, but PMC for one use Klippel products and do final testing in anechoic chambers. Loads of people made great speakers before Klippel and still do without it.

If a small/medium speaker business has been happily making and selling speakers for years, the commercial reality is that spending $100,000 or more on new equipment makes no sense.

 

[Katji]

small/medium speaker business

That's the key thing, and it's hard to see how or when the cost of such technology would become more affordable. The world changes, though - so to speak -and there is much of tthat happening now.

 

[Katji]

The entire design process will be automated, and the cost constraint, the specified cost structure/s can be modelled as part of the process. Gradual trend to automation has been part of the story of computers all along.

 

[amirm]

If a small/medium speaker business has been happily making and selling speakers for years, the commercial reality is that spending $100,000 or more on new equipment makes no sense.

The electronics guys have been making and selling that gear for years without proper measurements as well. Yet I keep hearing left and right that they are now buying $30,000 Audio Precision analyzers to make sure they can make proper measurements. Lest they want us to be the first who does and sees problems.

Just as well, I expect speaker manufacturers, large and small, to buy Klippel NFS. If they already have the baseline Klippel hardware and don't don't need all the bells and whistles, an NFS add-on can be $50K or less. We have seen the beginning of this trend and I am confident it will grow rapidly with time. The value proposition is unique and quite high.