Is it possible to use REW to measure RCA outpu
- Thread starter Smitty
- Start date
Justin Zazzi
Wave Shepherd - aka Jazzi
Absolutely.
You can do it through a headphone in... but far better to use a decent audio interface that doubles as a mic interface
i use a Scarlett focusrite 2i2 and each input can be made to analyse a line level signal
set it as the input with pink noise playing and hit rta like normal ie it’s no different from using a mic as an input, a mic turns air movement into electrical... the rca signal starts as electrical ����
i use a Scarlett focusrite 2i2 and each input can be made to analyse a line level signal
set it as the input with pink noise playing and hit rta like normal ie it’s no different from using a mic as an input, a mic turns air movement into electrical... the rca signal starts as electrical ����
Thank you. After I was done laughing at Jazzi's response, I checked out some videos and posts. That unit or similar was mentioned/used.
In this case, I don't need high end. I only want to get a basic look at the OEM eq, see if the bass rolls off with volume, and find where it starts clipping. I'd prefer to spend the money on a new head unit eventually.
This RTA measurement was done on the same vehicle but a newer year. The radio has been updated but, I imagine the eq is similar since the speakers have been the same for years. If I read it correctly, it's a 21.5db swing. That curve is very similar to what I've been fighting. In his vehicle, the bass doesn't seem to roll off with volume.
It is clear, the best solution is a new head unit but that's going to be a while.
I have considered a unit that will knock the peaks off of that signal then use my dsp to process a flatter curve but, that's a bandaid and seems counterproductive.
In this case, I don't need high end. I only want to get a basic look at the OEM eq, see if the bass rolls off with volume, and find where it starts clipping. I'd prefer to spend the money on a new head unit eventually.
This RTA measurement was done on the same vehicle but a newer year. The radio has been updated but, I imagine the eq is similar since the speakers have been the same for years. If I read it correctly, it's a 21.5db swing. That curve is very similar to what I've been fighting. In his vehicle, the bass doesn't seem to roll off with volume.
It is clear, the best solution is a new head unit but that's going to be a while.
I have considered a unit that will knock the peaks off of that signal then use my dsp to process a flatter curve but, that's a bandaid and seems counterproductive.
Justin Zazzi
Wave Shepherd - aka Jazzi
Sorry, couldn't help it!
But yeah, like dumdum mentions you can just play pink noise and then "measure" it using the line input on some sound card you have. Just be careful about the voltage you try to measure. Anything over ~2vrms starts getting sketchy for sound card inputs like this. You can knock down the voltage using a line-output-converter or by building a voltage divider with some resistors.
I outlined the parts I used here: https://www.f150forum.com/f30/head-...s-high-level-vs-low-level-467373/#post6488321
I just used all of this to get a nice loopback for about $20 in cost at the time. I used the external usb sound card so I didn't fry my computer. I've done that before, now I try to use external if I am connecting something that could potentially send too much in.
I output the sound from the computer and played a sweep with REW. It then went into the HU and out to my RCA attenuator (to lower the level to less than 1v) which then went back into the usb sound card.
Note: Everytime you adjust the level of the attenuator, make sure to calibrate the sound card loop (without HU) in REW. That attenuator does not change the frequency equally when adjusted.
I just used all of this to get a nice loopback for about $20 in cost at the time. I used the external usb sound card so I didn't fry my computer. I've done that before, now I try to use external if I am connecting something that could potentially send too much in.
I output the sound from the computer and played a sweep with REW. It then went into the HU and out to my RCA attenuator (to lower the level to less than 1v) which then went back into the usb sound card.
Note: Everytime you adjust the level of the attenuator, make sure to calibrate the sound card loop (without HU) in REW. That attenuator does not change the frequency equally when adjusted.
Sooo, you're saying I could possibly also get a new motherboard out of this? [emoji23]
All jokes aside, thank you. That should get me the little bit of info I'm looking for.