SPL to PSI

[akrod2as 2]

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?

[akrod2as 2]

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

[mr.sagat 10]

1 bar of pressure is equivalent to 193 db.

[akrod2as 2]

Thought it was 193.98

Edited May 8, 2010 by John Holmes

[thehawk93 2]

I'm here watching this to see if anything comes of it....

[akrod2as 2]

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.

[mr.sagat 10]

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....

[akrod2as 2]

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.