RSP-1098 Bass Calibration Observations

[whmacs]

Hi All,
More of an observation than anything else, but I recently recalibrating my subwoofer using Digital Video Essentials. This disk has a 75db output level. So as usual I set the front left speaker to output 75db (77 on RSP-1098) with the speaker level set to 0db. I then cut over to the sub test signal from the DVD and the SPL metre was reading 85db from the sub(At this volume level the walls where starting to shake!). As you could image, the sub was way too loud.
The interesting thing was, I then repeated the calibration, but this time set the RSP-1098's volume to a level where I usually watch movies at (63). This lead to a SPL reading of 70 for the front left speaker and the sub also at 70db. Things sounded good, with deep bass that blended well with the speakers. I didn't touch any of the level setting when I rechecked the calibration at vol 63.
So it seems that bass response is not linear as volume increases (at least in relation to the other speakers). This then begs the question why calibrate at 75db (which is way too loud, in my case at least) and not calibrate a comfortable listening volume? If I was to calibrate both speakers and subwoofer at 75db, bass would be very light at the normal 63 listening level.
Just some random thoughts....

cheers,
Stephen




My Home Theatre

[Kevin D]

Not sure how literal you were about the walls shaking, but even an air vent rattle could be louder than the 75db coming from the sub.

You would need a specturm analyzer to really tell, but I would be surprised if it WASNT linear between all the channels.

A good reason that you calibrate high like that is too get above normal room noise. One possibility is maybe your subwoofer and main channel amps are not linear given a linear voltage change compared to each other.

Really it's all what sounds good to you, but I would suspect if you zeroed out all the levels and played a known good test disc you would proabably get nearly the same voltage out of the outputs at all volume levels (taking away all the other factors; amp, speakers, room, etc..)

Kevin D.

[Hd4life]

Hey Whmac question for you and anyone else for that matter,

"
So as usual I set the front left speaker to output 75db (77 on RSP-109 with the speaker level set to 0db."

How do you do that? How can you get the front left or right speaker up to 77 db with the speaker level at 0..? I'm not following you on this.

I too am going through calabration and what I do is set the front left to around 72 db with the volume knob. I then set everything eles using the test tones and their volum controls. Am i doing something wrong..? does someone have a right or better way to do this?

thanks

[whmacs]

Hi Hd4life,
Great to hear that you got you RSP-1098 back! I assume they upgraded it to v2.1.1 for you? Any issues with the surrounds (if you have a 7.1 system)?

To get 75db on a SPL metre, set the left speaker level to 0db in the level menu. Now simply turn up the volume on the RSP-1098 until the SPL metre is reading 75db (the 77 I was referring to above is the volume reading on my particular RSP-1098 to obtain a 75db reading through my left front speaker, 75db on your system will probably have a slightly different volume reading on the RSP-1098 display). Now don't touch the volume control anymore and just use the level adjustments to get all speakers reading 75db from your seated position.

Of course this isn't an exact science, adjust things until you are happy with the sound. For example, I recalibrated at an RSP-1098 volume level of 61 (about 70db) as I found this gave better subwoofer blending (deeper bass response) than calibrating everything at 75db, (77 on the RSP-1098 volume display) as I never listen to a movie this loud and the bass response seemed to be lacking when I turned the volume down to 61. I also have my four rear speakers bumped up a couple of db as I love those rear surround effects

cheers,
Stephen




My Home Theatre