Dear Acoustat6: I just made the measurements of SPL using one of my test records: the CBS STR130.
From my seat position ( 2.90m. ), from left and right channel measures each one by separate and measure with both working, using the 1,000 Hz tone at 0db level I measure: 86db individual and with both running 94db.
Measuring at the same position but with a normal LP ( with music not test tone. ) I obtain 84db with peaks at 92-93db. Hey Bob p we are almost similar on the subject! and like you works for me too.
Now, it is possible that if I take those same measurements say tonight at two O'clock in the morning maybe I have to lower the volume by 2-3db because the ground floor noise is different ( at least where I live ): more silent.
I know that your approach about that 1,000hz is because is the one used as standard in the recording industry ( along the 400hz. ) as a fact is the reference on the RIAA where at 1khz the db level is 0.
Unfortunatelly the whole audio recording/reproduction is not perfect so we can't have a precise number ( like the 83db ) for all, we can/could be around that number that seems to me has sense or at least more that your flat frequency ( alone ) goal. Btw and looking more in deep to your phono stage I can say that the manufacturer specification for the inverse RIAA eq deviation: +.- 1db from 25 to 25khz is really on a not desired side because that +,- 1db frequency deviation ( every time that ocur through the RIAA wide frequency response ) makes a degradation/coloration to the recording/cartridge signal because does not affect a single frequency but almost three octaves due that the RIAA is a curve not linear, the other subject here is the fact that the manufacturer specs start at 25hz not 20hz that is the RIAA standard and this means that below 25hz the deviation is bigger than 1db and this fact means that what you are hearing from 60hz an down is really worst.
I know that you like what you have but what really are you hearing?, certainly not what is on the recording.
Facts like this one goes against your goal, the good news is that you always can/could improve about.
From my seat position ( 2.90m. ), from left and right channel measures each one by separate and measure with both working, using the 1,000 Hz tone at 0db level I measure: 86db individual and with both running 94db.
Measuring at the same position but with a normal LP ( with music not test tone. ) I obtain 84db with peaks at 92-93db. Hey Bob p we are almost similar on the subject! and like you works for me too.
Now, it is possible that if I take those same measurements say tonight at two O'clock in the morning maybe I have to lower the volume by 2-3db because the ground floor noise is different ( at least where I live ): more silent.
I know that your approach about that 1,000hz is because is the one used as standard in the recording industry ( along the 400hz. ) as a fact is the reference on the RIAA where at 1khz the db level is 0.
Unfortunatelly the whole audio recording/reproduction is not perfect so we can't have a precise number ( like the 83db ) for all, we can/could be around that number that seems to me has sense or at least more that your flat frequency ( alone ) goal. Btw and looking more in deep to your phono stage I can say that the manufacturer specification for the inverse RIAA eq deviation: +.- 1db from 25 to 25khz is really on a not desired side because that +,- 1db frequency deviation ( every time that ocur through the RIAA wide frequency response ) makes a degradation/coloration to the recording/cartridge signal because does not affect a single frequency but almost three octaves due that the RIAA is a curve not linear, the other subject here is the fact that the manufacturer specs start at 25hz not 20hz that is the RIAA standard and this means that below 25hz the deviation is bigger than 1db and this fact means that what you are hearing from 60hz an down is really worst.
I know that you like what you have but what really are you hearing?, certainly not what is on the recording.
Facts like this one goes against your goal, the good news is that you always can/could improve about.