REW and Raspberry Pi 4 Raspbian Buster install

HAL

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Hello,
I just received the latest Raspberry Pi 4 B+ with 2GB of memory. It needs Raspbian Buster to run, so installed that today on a fresh SDXC card and everything is running.

Buster OS now comes with JAVA 11 installed with the OS image.

I tried the install of REW beta15, but came back stating no JAVA 8 JRE installed, and JAVA 8 is no longer available to download from what I can find for Raspbian.

Any ideas of a possible work around?

Best regards,
HAL
 

HAL

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Yes, the command: sudo apt-get install openjdk-8-jre
worked correctly and REW beta15 installed and is running on Buster.
 

Antonio Di Motta

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Hi, I wanted to have some news on how REW works on Raspberry Pi 4. What sound card do you use it with? with what version of REW?
Currently I use a Raspberry Pi3 + with Soundcard Stereo soundcard with S.O. Updated Raspbian Jessie and JRE Oracle 8 update 221 and REW 5.20 beta 24.

Thanks
 

HAL

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I am using the Dayton Audio UMM-6 mic and internal sound card to start. Got the correct TRRS to RCA cable to use with the RPi4.
 

Antonio Di Motta

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The photo of my profile displays the measuring instrument built with Raspberry Pi3 and S.O. Xubuntu version 16.04 USB Audio card with PCM2902 chipset and REW 5.19 .
It works very well ... but now I'm refining the project and I would like to use a Raspberry Pi4 with a dedicated I2C sound card to get to the sample rate of 96/192Khz ...
 

Antonio Di Motta

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The audio output of the raspberry is extremely poor and you will not be able to make reliable measurements, especially as regards distortion.
I do not understand how you can connect the microphone to the raspberry since it does not have an audio input.
To connect the microphone you must have an audio pre-amplifier with a gain of at least 10db and a phantom power supply for the microphone as well
as a sound card with stereo output and input to work properly with REW.
 

HAL

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My other option is to use the Danville Signal Processing dspMusik 2x8 digital crossover running at 24bit/192KHz for the ADC and DAC's. I have the ADC and DAC's programmed to allow measurements via the USB bus. Works well with both the RPi3 and RPi4 running Buster.
 

Antonio Di Motta

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Ok I hadn't seen that the Dayton UMM-6 microphone was a USB interface, so I can explain how you manage not to have an ADC section on the raspberry.
The second option is interesting and has very high characteristics because the dspMusik is a very professional device, a pity that it has a much higher cost than the raspberry processing system.
My project aims to have everything needed to make reliable electro-acoustic measurements, but above all to have a cost that is accessible to everyone.
I have some problems finding a good sound card natively supported by Raspberry.
Now I'm trying a HiFiberry DAC + ADC but even this one, despite declaring good performances, has an input section with not very good electrical characteristics.
If you can attach some example of level and impedance measurement, I do the same in order to compare the systems.
Regards
Antonio Di Motta
 

HAL

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There is no way to do an impedance measurement without an ADC, so SPL is the measurements to make.
 

Antonio Di Motta

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I thought that on the dspMusik 2x8 you also had the optional card
Input Module: ADC: AKM AK5397 (S / N> 120 dBA). It would have been perfect to carry out all the measures foreseen by the REW software.
So the measurement system is a bit limited, you should add an ADC converter to have a complete measurement system ..
 

HAL

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For the RPi4 version I am just using the built in DAC's with the USB mic. I already have a CLIO Pocket for the other measurements, but larger than the RPi4 setup. If I did not, then would use the dspMusik 2x8. It would be the largest of the 3 setups to use, so for something small, the RPi4 is great and small.
 

Antonio Di Motta

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I see that you have different systems to make measurements, I only use the instrument built and designed around the Raspberry Pi 3+ to make all the measurements
including the measurement of electrical resistance in DC useful for calculating the Thiele / Small parameters of the speakers essential for the loudspeaker design.
This realization is designed for non-professional enthusiasts who want to have fun without investing a lot of money in professional equipment.
Precisely for this reason, I use the fantastic REW software and try to verify the good functioning on the Raspberry.
I always thank Jhon for making it and continually updated.
 

Antonio Di Motta

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The microphone I used was made with a Panasonic capsule modified to significantly reduce
distortion at high sound pressures, the useful range is 10Hz 20Khz, and is calibrated by difference
compared to a reference microphone from Rohde & Schwarz.
For the realization it is possible to see this site: http://www.linkwitzlab.com/sys_test.htm#Mic
 

Antonio Di Motta

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The self-built microphone requires a low-noise preamplifier with a 10db gain and a -9 Vdc power supply for the electret capsule.
In this configuration it is possible to reach sound pressure levels greater than 130db. Furthermore, in order to work with the Raspberry it
is necessary to have an ADC converter with a sampling frequency of at least 44Khz and a resolution of 16 bits.
Surely your solution with a USB microphone is simpler and does not need an ADC as it is built into the microphone, but I don't know if it has the same performance, especially in terms of dynamics and distortion.
 

HAL

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Have the RPi4 connected to the TRRS cable to RCA cables and with the Dayton Audio UMM-6 mic have a it running with REW Beta 24 and Buster OS. Have test signals generating from the on board DAC and will be using it shortly for some measurements. Nice and portable system to use. Probably will try the integrated larger LED touch screen display to make it more portable, instead of the HDMI cable connected display and Bluetooth keyboard.
 

Antonio Di Motta

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Well, surely the system will work but a little limited because the performance of the DAC on the card is very poor and due to the lack of an ADC converter it does not allow to make impedance measurements. Good idea to use a touch screen, however good work and update us on the realization .
thanks a lot
 

Antonio Di Motta

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I forgot to mention that in this forum I am describing the realization of a measuring instrument based on Raspberry, you can find some interesting ideas to complete your realization. The discussion is entitled Make a good measurement system with REW and Raspberry.
Thanks
 
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