Just bought A SPL meter...

JerryCulp

Stunt Coordinator
Joined
Mar 28, 2003
Messages
76
and I learned a few things.
1. My ears are not the best way to calibrate my speakers. using the SPL, I adjusted the speakers and the system sounds a few times better, most notably in the surrounds.
2. I am a Bass pig. Before the SPL I had the receiver set to +4 for the sub. The SPL says -4. I now know why my ears hurt when I watched a movie at seemingly low volume levels. The bass was was way over the top, with the rest of the sound at ~80db, the bass probably way past 100db, and that was without considering peak.levels.
3. Most importantly, I should have listened to to all the experts that said a SPL is a must have!
 

joe rizzuto

Stunt Coordinator
Joined
Jun 10, 2002
Messages
140
it's my understanding that the sub should be set at 0 and to do adjustments at the sub itself.
did you use a tune up dvd or the receiver's test tones?
if not, i suggest a tune up dvd would be the ticket.
it will help your sound as much as the spl meter did.
 

Steve_AS

Second Unit
Joined
Feb 4, 2002
Messages
412
and I learned a few things.
1. My ears are not the best way to calibrate my speakers. using the SPL, I adjusted the speakers and the system sounds a few times better, most notably in the surrounds.
2. I am a Bass pig. Before the SPL I had the receiver set to +4 for the sub. The SPL says -4. I now know why my ears hurt when I watched a movie at seemingly low volume levels. The bass was was way over the top, with the rest of the sound at ~80db, the bass probably way past 100db, and that was without considering peak.levels.
3. Most importantly, I should have listened to to all the experts that said a SPL is a must have!
If your SPL metere is the classic Radio Shack analog one, it's not accurate at either end of the freqency spectrum. Several sites with correction tables exist, e.g.

http://www.rivesaudio.com/files/Spl.pdf
 

Lee Carbray

Second Unit
Joined
Oct 23, 2002
Messages
308
it's my understanding that the sub should be set at 0 and to do adjustments at the sub itself
It does not matter where you do the adjustments. There are however a few things to think about before you chose. Some subs do not have very sensitive auto on circuitry and if you have the sub out too low(not necessarily in the negative region but most likely) then the sub may not turn on. As well if you have the sub out in the positive region there is more THD in the signal. Now you may not be able to hear the noise so it is a toss up whether you want it there or not.

The best compromise of course is to set it a zero and adjust it at the sub. The you have room to pump it up or tone it down depending on your mood.

Steve is right, the Radio shack meters, analog and digital are not accurate. However because you are using pink noise that table is not going to help you. When you calibrate your mains you do not have to worry about the 1 db inaccuracy at the top end. On the bottom end the pink noise will read 3-5 db low on the meter so to calibrate equal to the mains make sure to get a reading of 3-5 db below you calibration point. In other words if the meter reads 85 db for your mains then the sub should be reading 80-82 db
 

JerryCulp

Stunt Coordinator
Joined
Mar 28, 2003
Messages
76
It is a R-shack meter. I used the tones from receiver, an Onkyo 510 (receiver in the HT-S760).
The freq range says it goes low enough for my current sub, 35hz.
But my SVS 20-39 PCi is on the UPS truck and should be here tomorrow or Friday. Now that i have ssome loose idea of how much bass is about right, I hope I can set the SVS close enough with R-shack meter.
 

JerryCulp

Stunt Coordinator
Joined
Mar 28, 2003
Messages
76
Because I used the tones from the receiver, I had to use the adjustment on the receiver. I set the sub at 0 and used the remote to adjust. The tone doesnt play long enough for me to take a reading at the listening position and adjust the sub. Not in any amount time I want to spend doing it.
My friend has one of teh tune up disks, and I am going to borrow it from him.
 

Jeff Gatie

Lead Actor
Senior HTF Member
Joined
Aug 19, 2002
Messages
6,531
To answer the pink noise question:

Pink noise is a sum/average of all frequencies. Most test tones are made of pink noise. The Rat Shack meter correction tables list corrections for specific frequencies (i.e the meter may be -5dB at 25Hz and +2dB at 18 Hz, etc.). Since pink noise is composed of all frequencies - which correction factor are you going to use? The answer - none of them. Vince Maskeeper did a test on this effect and found the correction values really mean nothing when adjusting via pink noise. Just adjust to the proper level on the SPL meter and forget about the correction values.
 

Steve_AS

Second Unit
Joined
Feb 4, 2002
Messages
412
Pink noise is a sum/average of all frequencies. Most test tones are made of pink noise. The Rat Shack meter correction tables list corrections for specific frequencies (i.e the meter may be -5dB at 25Hz and +2dB at 18 Hz, etc.). Since pink noise is composed of all frequencies - which correction factor are you going to use? The answer - none of them. Vince Maskeeper did a test on this effect and found the correction values really mean nothing when adjusting via pink noise. Just adjust to the proper level on the SPL meter and forget about the correction values.
Ah, so. The adjustments are meant for establishing frequency response of room and/or equipment. I use frequency test tones for that.
 

Matthew-K

Stunt Coordinator
Joined
May 24, 2002
Messages
95
I thought the SPL meter was used to set all of the speakers to the same db range from the listening position? i.e. you would get the same reading from each speaker, from your listening position, if you have your speakers adjusted correctly. Is there more to the SPL meters than I thought?
 

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