Regarding impedance measurements: Thank you for all of the thoughts on this subject. It will help me when I eventually get around to updating my impedance measurement equipment. For this current project, the accuracy of my impedance sweep is adequate. All of the final adjustments will be based on acoustical measurements and subjective listening.
This will be my last passive speaker project for a while. The next several projects in my queue are all active. So an accurate calibrated impedance rig is less important to me in the near term.
My wife is an electrical engineer who ran an EMI/EMC lab for 30 years. Normally she has little interest in my hobby (although she enjoys the finished products) because it too closely resembles the work she did for decades. But lately she has been thinking about my test equipment, and she has some ideas on what I need. Her list is rather pricey and it may be overkill, but I am inclined to follow her guidance. She points out that the equipment I need is far less expensive than what she used in her lab because I am in the low frequency range (meaning less than 100 MHz).
But as I said, my next several projects will be active, so I am in no hurry to upgrade from DATS...
j.
This will be my last passive speaker project for a while. The next several projects in my queue are all active. So an accurate calibrated impedance rig is less important to me in the near term.
My wife is an electrical engineer who ran an EMI/EMC lab for 30 years. Normally she has little interest in my hobby (although she enjoys the finished products) because it too closely resembles the work she did for decades. But lately she has been thinking about my test equipment, and she has some ideas on what I need. Her list is rather pricey and it may be overkill, but I am inclined to follow her guidance. She points out that the equipment I need is far less expensive than what she used in her lab because I am in the low frequency range (meaning less than 100 MHz).
But as I said, my next several projects will be active, so I am in no hurry to upgrade from DATS...
j.
Hello,
There is a wide range of instruments to choose from.
QuantAsylum.com has quality instruments affordably priced that are designed for factory floor QA / QC application. I use mine to toss in a cardboard box with my laptop and go. Very good tools for DIY use.
Take a look at:
QA 403 Analyzer
QA 461 Transducer Driver and impendence measurement tool
QA 472 Low Noise Mic Preamplifier and power supply
The lab grade equipment stays home on the bench.
@hifijim if you will, please tell us what tools you are considering.
Thanks DT
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Very interesting development Jim,
If you would like to fork the thread, I’ll be happy to share what I have found, having recently surveyed the current microphone marketplace.
Also, there is an upcoming new DATS-LA that has an amp built in and can measure Le(x), BL(x) and Kms(x) of transducers…
If you would like to fork the thread, I’ll be happy to share what I have found, having recently surveyed the current microphone marketplace.
Also, there is an upcoming new DATS-LA that has an amp built in and can measure Le(x), BL(x) and Kms(x) of transducers…
The QuantAsylum equipment looks intriguing. Thanks @DualTriode
I am also looking forward to seeing the specs on the DATS-LA device...
I am also looking forward to seeing the specs on the DATS-LA device...
It is for when somebody wants to get serieus about mostly electronics.
There are plenty of other audio interfaces that are (more than) good enough for loudspeaker measurements incl distortion and are just much more affordable.
Simple impedance measurements can just be done with a series resistor.
If you want a better setup, a small resistor works better, even better is inside the feedback loop of the power amplifier.
Curious about the price and implementation here.
Currently I am working on a similar project with someone, the hardware is tricky but still very doable.
The magic here is all within the interface as well as the math, signals and data acquisition behind it.
We are still on the fence of making it open source or not.
Besides, there is a lot more than just those few parameters, things like motor and long term (temperature) stability etc.
Something that is basically never shown in Klippel reports that are available.
When I talked with Bryan Myers at the Speaker Design Competition, he said there are 2 versions in development. One has maybe a 300W amp, and the other has a 1200W amp. He was saying $500 for the smaller and $1500-2k for the larger. Using the larger signal testing with this/these device(s) was said to be a game changer, and actually matches that of the Klippel by comparison.
Why would one design an entire amplifier, if they can just be bought for cheap everywhere?
That sounds like reinventing the wheel to me for additional costs.
I much rather focus on just the interface and mostly the software behind it.
Large signal testing is a bit more than just BL(x), Kms(x) and Le(x) if you want to do it well.
If you are confused, here is an example test amplifier from the SoundCheck people.
https://www.listeninc.com/products/...pplies-amplifiers/scamp-audio-test-amplifier/
SoundCheck sells parts and pieces that integrate into a calibrated plug and play / calibrated test system.
We have a couple of Listen microphones and a Listen microphone preamplifier on my test equipment bench.
That still doesn't explain anything.
It's not hard at all to calibrate a system, even with some 3rd party amplifiers.
I believe that you understand completely.
In range of options between unable and unwilling you are the latter.
I think it's quite obvious that the question simply hasn't been answered.
To show any willingness, I am all ear.
Btw. No need to get personal in technical discussions.
Thank you.