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Announcement: ASR Will Be Measuring Speakers!

deafenears

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Unlike the video above, I assembled 99% of the unit myself with just an occasional help from my wife for heavy items. Did not want to impose on her any more than I had already done with this expensive purchase! The assembly took about 3 to 4 days, with 12 to 15 hour days.
Any chance you could share with us a time lapse of your Klippel NFS set up going up?
 

rajapruk

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Dynamic compression is important for me, related to distortion. Maybe you can measure at different SPLs and then compare the Distortion results in some way?
 
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amirm

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Any chance you could share with us a time lapse of your Klippel NFS set up going up?
Going up? You mean build it? If that is already done. The measurements I showed where from it working.

If you mean measuring future speakers, yes, but first I have to clean up the mess around it in our garage. :)
 
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amirm

amirm

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Dynamic compression is important for me, related to distortion. Maybe you can measure at different SPLs and then compare the Distortion results in some way?
The concern is the same as amplifiers with risk of damage. That said, I did that with the little JBL speaker and it showed very slight increase in distortion that way. I will probably make a new thread on discussing what to measure and how.
 

blueone

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Are you planning to haul one of your Salon2s down to the garage for measurement? I bet there are several people here (including me) who would be fascinated by what you find.
 

Indien29

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Hello everyone, hello Amir
We follow your adventures from the Hcfr forum in France, it's good news to learn that a Klippel NFS will soon allow repetitive measurements to be able to compare different speaker models.
Here is my opinion on what would be both useful and easy to read for an understanding accessible to all.

Editing a complete spinorama for the lack of directivity can be simplicity for the uninitiated.

The publication of simplified measurements would be fabulous for a quick reading, I think of PIR (Predicted In Room used by Harman) alongside a measurement of DI and a full spectrogram.

Then a graph with ventilated distortions, THD (Total Harmonic Distortion) and detailled harmonics (H2, H3, H4 etc ...)

The Harman PIR has the advantage to be simply possible for comparaison directly in room at home, by a measurement of the RTA including micro turning (the "MMM Mouving Micro Mouvement" method of Jean Luc Ohl : http://www.ohl.to/audio/downloads/MMM-moving-mic-measurement.pdf

This simply method offer a response fairly close to PIR in the room above 500 / 700 http://www.ohl.to/
 
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mkawa

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superb! what i can think of early on is to work closely with a grassroots speaker builder with access to anechoic spin measurements to make early measurements on your rig and compare them with the results from the traditional measurement methods

you would need a manufacturer small enough to do everything in house but large enough to get consistent manufacturing results and large enough to be rigorously measuring designs and samples off the line.
 

MZKM

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Here’s something I bet readers here would appreciate:

Measure speakers being run with low SINAD DACs & amps versus high SINAD DACs & amps.

Not for regular measurements of course, but something you do once or maybe more than once just to investigate. Not sure though if this system even allows for this.


These kind of systems/measurements are not precise enough to matter. But yes, I am using the Behringer amp I tested for all my measurements since it has balanced inputs and it was gathering dust. And it has plenty of power as to not distort itself

Your measurements. Or, did you already test this and the distortion of the A500 was found to be nonsequential?
 

murraycamp

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Excellent news indeed. Thanks Amir!
 
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amirm

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Are you planning to haul one of your Salon2s down to the garage for measurement? I bet there are several people here (including me) who would be fascinated by what you find.
That was the original plan until I tested the system at its limit and hit the ceiling. :) I will have to carefully measure to see if is possible in the current space.
 
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amirm

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Here’s something I bet readers here would appreciate:

Measure speakers being run with low SINAD DACs & amps versus high SINAD DACs & amps.

Not for regular measurements of course, but something you do once or maybe more than once just to investigate. Not sure though if this system even allows for this.
This kind of system is not usable for that kind of comparison. There is enough ambient noise to cover the performance of the electronics. And we have the distortions of the microphone and test amp in there. Basically we are talking about SINADs of 50 and below in acoustic measurement. To do that kind of test you need an anechoic chamber that is super quiet. With microphone systems that are the same (some expensive B&K ones that cancel internal noise).
 

Mauro

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Great Amir! Have fun!

I remember Andrew Jones stating that the best source for speakers measurements is the Italian magazine (warning I am Italian ;) ) AUDIOREVIEW

Links to KEF LS50 and KEF LS50W, in case you might find them useful, if you need translations of some parts let me know.

PS: About IMD ... and Andrew Jones ...and coaxial speakers, his words:

“Back in the days when I was at KEF and we were developing the Uni-Q drivers, we also questioned the audibility of any fm or am distortion due to the moving cone.
AM comes from the change in loading of the waveguide upon the tweeter as the cone moves forward or backward. If you measure the tweeter frequency response for different positions of the cone you do see changes in the frequency response of the tweeter, both in shape and sensitivity. This contributes to the AM.
The fact that the cone is moving due to the bass signals does give rise to some doppler […] We also measure the Quad ESL63 as a reference point. Being a full range diaphragm, this should have the highest levels of doppler.
The level of sidebands were lower but not greatly so. From this we made a simple conclusion. If the ESL sounds as good as it obviously does, with these levels of doppler, then it is a distortion mechanism we do not have to worry too much about!!
Of course this still leaves the issues of AM. The clear solution to this is to minimize cone displacement.
A two way based coax speaker system is the most difficult to engineer. Not only does the cone move a long way, but the half-roll surround that is neccessary for such displacement wreaks havock on the diffraction of the tweeter wavefront on axis. That is one reason why co-axials should always be listenened to around 10-15 deg off-axis. […]
Limiting the bandwidth of the driver to around 200 or 300Hz, in a three way system, greatly diminishes all these negative effects, and allows one to design a surround that does not mess up the diffraction, so that even on axis the response is good.
This is the approach I have used ever since.”


“[…] KEF seem to have a good handle these days on getting a smooth response from their two way drivers (LS50 for example) with good surround design and good transition into the cone, but that does not solve the issue of large cone displacement.”
 
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daverosenthal

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Long time lurker/audio enthusiast/DIY speaker builder/engineer here. You just motivated me to create an account, post my first message, and setup $10/mo flowing on Patreon! Thrilled to see the forthcoming speaker data, participate in the discussion about what the important characteristics to measure are, and upend some conventional wisdom.

A modest suggestion as we get going: There are so many ways to evaluate a speaker and understand the psychoacoustic tradeoffs that it seems inevitable that the "standard graphs" will change over time as we learn, leading to difficulty comparing speakers reviewed at different times. It would be amazing if there was a way to be able to generate the latest graphs for previously-tested speakers. This might go hand-in-hand with an open database of all of the raw measurement data for the speakers.

...OK, I don't mean to add work, you're just getting me excited about what's coming!
 

Cahudson42

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Sounds a bit that we need to backup - and first develop an ordered list of what quantitative objective tests will likely result in meaningful 'perceived' listening 'enjoyment'.. Distortion metrics (lack of) etc.?

Or did I miss that one already exists?
 
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amirm

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A modest suggestion as we get going: There are so many ways to evaluate a speaker and understand the psychoacoustic tradeoffs that it seems inevitable that the "standard graphs" will change over time as we learn, leading to difficulty comparing speakers reviewed at different times. It would be amazing if there was a way to be able to generate the latest graphs for previously-tested speakers. This might go hand-in-hand with an open database of all of the raw measurement data for the speakers.
Thanks very much for the kind support and welcome to the forum. That is a good point regarding a database of graphs. Had not thought about the fact that most of the information will be in the form of graphs than single numbers. Will have to think about it. @pozz, let's discuss....
 
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amirm

amirm

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Sounds a bit that we need to backup - and first develop an ordered list of what quantitative objective tests will likely result in meaningful 'perceived' listening 'enjoyment'.. Distortion metrics (lack of) etc.?

Or did I miss that one already exists?
Yes, we have had a few of those threads. :) Search for "spinorama" and you should be able to find them.
 
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