Bought a Radioshack SPL meter and

[boom3]

better late than never, ah guess...

I also bought the analog RS SPL meter. I bought the Rives audio test CD and printed out the graph paper and used the test tracks that are set to compensate for the RS meter (poor man's "calibration"). I think the excercise was a waste of time. The Rives disc uses sine wave tones, which create standing waves in the room, and the 'frequency response" I took was not representative of what my envelope of response, as measured with my ears, should be, especially above 200 Hz. I also cut-off the test at 8 KHz for fear of frying my tweeters. I'd love to see a test disc with pink noise (I'm sure they exist somewhere).

I've also used the SPL meter to see what my personal maximum loudness, in my living room, with my systems is. That is 102 dB, "slow" setting, at the listening position, which is equidistant from four CW IIs in a 25 x 16 room. Typical listening is a lot less than this.

[DrWho]

Having been to a lot of concerts, and having played with a lot of home stereos in my life, in my estimation it is not possible to reproduce the sound in an auditorium in your living room. I'm not referring to any raw SPL numbers, or sound pressure levels. It's a matter of acoustic space and time...

I couldn't agree with you more! That's why I look at the entire system (the process of recording and playing back at home) as an art form - a process of creation...making new sounds that could otherwise never be experienced. It is not an attempt to reproduce an original live sound. If it were possible to recreate a live sonic event, then it would just be a matter of physics, building the right mic and perfect acoustic envioronments.

This is also why room acoustics is such an important role with our playback system. We first want to keep the room natural sounding (ie, not an anechoic chamber), but we also want the sonic cues of the room to not interfere with the sonic cues on the recording. And there will be varying degrees of freedom depending on the music being listened to. I love the comparison between a close mic'ed rock group and a "far" mic'ed orchestra. Rock pretty much has no acoustical cues compared to the orchestra, so the acoustics of the room will by nature need to be different (a rock room could be more live than an orchestra room).

[DrWho]

"Heck, sometimes I just turn them off and go sit in the studio with the musicians to get a better feel for what's trying to be accomplished"

very cool approach, when mixing live, I always like to spend some sound check time on stage, listening to their mix, the monitors, etc. It's important to have what the musicians hear in your head when you go back to the desk.

Michael

And the best part is the musicians will like you more and usually have a better performance []

When setting up for a show I think I spend maybe 20% of my time behind the desk - 50% of my time on stage and then the last 30% walking around (including going outside and to the snackbar, etc etc...). Guys that sit any longer behind the desk most likely don't know what they're doing and are just turning knobs hoping to land on something that sounds good. They're also the guys that tend to ride the faders like no other during a show...if you get things set up right and the band is good, you should just be able to sit back and enjoy the show (maybe doing a little mixing between songs, cue-ing effects and all that...)

[sfogg]

" I'd love to see a test disc with pink noise (I'm sure they exist somewhere)."

Plenty of them have it. But with a SPL meter all you get is overall

system volume. To make any sort of FR graph with pink noise you need an

RTA or FFT or so on.

Shawn

[sfogg]

Mark,

" in my estimation it is not possible to reproduce the sound in an auditorium in your living room. "

Not with two channel playback anyway.

"Walk into any space blindfolded and speak a few words. You'll have the size of the room pegged in seconds. "

If you are ever near me let me know and I bet I can fool you or at least seriously trip you up.

Of course I'll have this running at the time...

http://www.lexicon.com/live/index.asp

And it is fairly *spooky* how well it works.

"I have been in some demonstration rooms with surround, or HT, or quad

or whatever the du jour multi-channel setup is, and I have heard

'spatial recreation' that was at least for minutes at a time, quite

convincing."

I would certainly agree with that... since that is how I have been listening to music for a long time now.

" And, oddly, the SPL was not very high at all. I'd even say it was

rather low by 2-channel standards. So, I think that with electronic

tricks we can get closer to creating large spaces in small ones"

Part of that may be that basically the total energy in the recording

isn't all coming at you from the front two speakers. Now a center

speaker is reproducing some of the music and the ambient queues in the

recording are coming out of the surrounds. Most matrix decoders are

considered 'energy preserving' which basically means the overall SPL in

the room doesn't change when switching from 2 speakers to 5 or 7. Yet

when one switches from 2 to 5 or 7 it does typically sound somewhat

quieter in multi-channel because of the greater number of sources.

Shawn

[edwinr]

mdeneen said: "...To compensate for this loss of realism about the time and space, there is a tendancy to turn up the SPL".

Up until recently I was convinced that 2 channel is all that I required to reproduce the music that I like with all the spatial cues and when necessary, the spl that I required. However, I am beginning to swing back to multi channel purely for the reason that 2 channel IS one dimensional. Even if you sit in the sweet spot, 2 channel is not going to give you the illusion of a live concert. I have temporarily installed a Hafler circuit, taking the out of phase information from the front channels and reproducing this information with 2 speakers (Heresys) driven by a spare amplifier. I know this information is mono and not ideal, but fed to the 2 rear speakers at low levels, the soundstage has opened up, and somehow has made it easier to discern fine detail in recordings. In addition I have found that it is not necessary to increase spl's when I am trying to listen deeper into the recordings. Also with a truly discrete multi-channel system, I guess there would be less tendancy to overload a room.

Two possibilities I am considering for a Heritage based multi-channel system is: Option 1 = Main speakers 2006 Klipschorns/Center speakers dual Heresy 3's/Rear Heresy 2's or 3's. Option 2 = La Scala mains/Heresy center/ Heresy rears. If I decide on option 1, my La Scalas will form part of a 2nd music system. Processor and amplification I am still working on...

[boom3]

re: my earlier comment about pink noise...should have said, bandwidth limited to each band of interest.

There is another method, which (it's early here) is called warbled (?), where the spectrum within the limited band is swept back and forth within the band of interest, said to nullify standing wave formation. I have a CD somewhere that does that...think I got it from Parts Express years ago.

Agree that only an RTA will give you "true" FR. These approximations with a cheap meter can only give an "envelope" of response.

BTW...Merry Christmas everyone.[]

I'm on my way home to Mississippi tomorrow to see the destruction for myself. I've been to New Orleans since the storm, but the damage to the Gulf Coast of MS was much more widespread.[]