Posted May 8, 201015 yr Got a question:Noticed that spl meters seem to have a simple pressure sensor in them. Does anyone know the formula to convert SPL to PSI? If so, I may just make a home brew SPL meter to test changes made. I have a 3-bar map sensor sitting around which can read the barometric at first for calibration, then anything after that. Or am I way off base here?
May 8, 201015 yr Author Did some searching and located a "chart" so to speak. 3-bar will definitely be too big of a sensor to use. I have a 2-bar that'd work. 5v, ground, and signal. I'll definitely need a clean and stable 5v supply
May 8, 201015 yr Author I'm here watching this to see if anything comes of it.... If anything, it'll simply give me a voltage and that'll tell me if changes raised or lowered the output. But I will need to make a step up circuit potentially since my current multimeter does not have the resolution necessary to see small changes.
May 9, 201015 yr Thought it was 193.98 hahah yeah, you're right. I was recalling off of memory. I knew it was somewhere around there. What I was getting at though is that spl is doubled every 3 db, so half a bar would be around 190 db and a quarter bar would be around 187 db. It's throwing me off that you're using a map sensor, map sensors read vacuum, not pressure on all na cars. You'd have better luck with a mass air flow meter imo. I was once told by a credible source that the termlab is a modified mass air for a mustang. Don't know if that's true though....
May 9, 201015 yr Author Thought it was 193.98 hahah yeah, you're right. I was recalling off of memory. I knew it was somewhere around there. What I was getting at though is that spl is doubled every 3 db, so half a bar would be around 190 db and a quarter bar would be around 187 db. It's throwing me off that you're using a map sensor, map sensors read vacuum, not pressure on all na cars. You'd have better luck with a mass air flow meter imo. I was once told by a credible source that the termlab is a modified mass air for a mustang. Don't know if that's true though....You're thinking of a 1bar map sensor. 2 and 3 bar read pressure as well as vacuum.
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