Science Experiment.

[doudou]

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On 6/28/2004 11:22:54 PM edwinr wrote:

Same here. I just bought the Radio Shack spl meter. I was really surprised that 90db in my very large room was loud! I am trying to imagine what the Klipschorns will sound like at 120db!

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don t try too hard, 120db is the treshold of pain.a such volume would blow your hear.

[ben.]

When I was in college in the Sound Recording program at SUNY Fredonia, Dave Fridmann taught a practicum. We were discussing monitoring levels for mixing and tracking. Most books suggest 90dBSPL as a "reference" level. In other words, that was the SPL at which your mix should sound the best, and most balanced.

He said (and I believe him wholeheartedly) that's hogwash (well, I'm paraphrasing here). He will (as do I) periodically turn the monitors up to that level, and above, to check balances and to make sure the upper mids and bass aren't getting wacky, but normal working levels are 70-80dBSPL. At those levels, it's actually easier to hear the details essential to the work.

BTW, a rough approximation of 90dB is the point where you have to raise your voice to carry on a conversation. In my world, 90dB average levels are tough to achieve with SWMB considered, if not obeyed. I've been known to skip a golfable evening to listen to music at some good levels lately, if I know wife & tike won't be home. I never did that with my JBL Northridge!

[fini]

I have taken to carrying around an SPL meter wherever I go. Before I start a conversation, I hold up a multi-lingual, laminated card, stating my desired sound pressure for this particular conversation (usually in the 75-85 db range), and start the conversation, allowing the other party to view the meter reading, so that they may stay within my comfort range. I think people like to know what I expect of them (volume-wise). I am thinking about adding a list of appropriate (generally, non-controversial) subjects to the card, so neither of us get riled-up.

[Deang]

rotflol

So what, the conversation ends at the point the allowable SPL is exceeded?

[fini]

Naw, it's usually when one of us says he does, he does likes the other's hat...

[rosypup]

""As the late Fritz Perls ( Psychologist and father of Gestalt Therapy) said....... There is Knowing and There is KNOWING""

I liked Fritz and ain't that a good quote.

It amazes me how a big chunk of metal can fly.

The new science is KNOWING the truth ahead of time. "There is knowing and there is KNOWING"

[doudou]

i ve a ducati with termignoni exaust system and i ve arrested by cops some month ago.they wanted to test the level of my bike because it seemed to them it make too much noise.

the "sonometre" (wich is a spl metre) said 96dB at top level, and it make all your body shake, your heart seems to stop.i had to replace the exaust system with the genuine one.

so bclarke421 when you said 90 dB is the level of a conversation, even if you scream, i m sure a single voice cannot reach a such volume.

[Ray Garrison]

Keep in mind that your Ducati reached 96dB at top level outdoors, without any room reinforcement. To reach that high a volume level from where they had their mike (presumeably a few feet away) in a free air environment is a lot different than measuring a loud speaker in a room.

Imagine revving up the bike in your living room. Absolute sound output would be the same, but relative loudness would be unbearable.

A speaker measuring 96dB inside a room reproducing your bike's sounds would not sound anywere near as loud as your bike outside registering the same level on the meter.

[mark1101]

Mark,

I have been riding motorcycles since I was a kid. I'm with you, I don't understand the fascination with the noise thing. I actually hate drawing attention to myself when I ride.

But to go even further, I always "test my yard" when I get the upstairs or downstairs systems cranking on the weekend. Especially since I moved the LaScalas upstairs. They are much louder than the corns. By "test the yard" I mean I actually go outside my house and walk around my yard to try and determine if the neighbors will be knocking (or the cops showing up) due to the music levels. Just common courtesy as well, and an education for me on how loud I KNOW I can go without expecting trouble. And it's plenty loud. No problem.

I hope to find out this weekend how this translates into SPL. I never measured it before, and I always wanted to know. I should have my Rat Shack meter later today.

[artto]

One thing most people do not take into consideration with SPL meters, VU meters and such is that unless the metering system has true 'peak hold' capabilities, the peak you observe on the meter are actually 10-12dB higher than indicated. This especially true of inexpensive meters like the Radio Shack, and in particular with analog meters because of the ballistic effect of the meter needle/mechanism. In fact in the old days recording/sound engineers used to deliberately allow for peak levels 12dB higher than the meters indicated to avoid clipping. So if you're using a Radio Shack SPL meter & it reads 100dB, you can expect the actual peaks to be 110dB or more, especially on recordings that do not employ a lot of compression or limiting (if any) such as Sheffield Labs or Telarc. Even on recordings that apply a lot of compression/limiting and have a compressed dynamic range such as rock, you can expect the meter to read at least 5dB lower than the actual SPL.

[ben.]

You've got to keep revving those Harleys when at a stop, 'cause they har'ly run...

[artto]

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On 6/29/2004 7:52:57 AM hwatkins wrote:

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On 6/29/2004 12:01:44 AM AK-4 wrote:

Wow - I set up my systems with a reference level of 85db and I have tried to run at that steady (kind of) state 90db and I am not able to maintain an enjoyable experience past 30 minutes or so. When I (play) a similar volume poolside I am estatic.

Probably these older ears have something to do with it...nah, can't be my fault

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It's not your older ears (lucky, eh!?) Its because of the room being a reverberant field. The decay time is longer and its easier for the average ambient sound level to be much higher than it is outside in free-field space. Thats why in my room I'm employing several acoustical techniques to keep the reverberation time and impulse response relatively consistent regardless of SPL level or frequency, as if the room were much larger. (easier said than done) Also consider that in a reverberant environment, especially the size of most rooms in domestic situations, the SPL level does not decline inversely proportional to the square of the distance much beyond 9'-12' (also due to reverberation)

[doudou]

my aim is not to catch attention.

in fact i bought my bike with the termignoni exaust.

once on the bike the sound is not very loud because i m in front of the exaust that fire in my back and i ve an helmet.

when the cops test the soud of my exaust system, i realised that my bike make too much noise because i was next to the cop using the spl meter, and without helmet.

i hope the policeman using the spl meter is not always the same, else he must be deaf

[doudou]

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On 7/2/2004 8:29:27 AM Ray Garrison wrote:

A speaker measuring 96dB inside a room reproducing your bike's sounds would not sound anywere near as loud as your bike outside registering the same level on the meter.

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it would not sound as loud as my bike at the same place but it would sound as loud as my bike making a 96db noise outdoor.

i often used spl meters in mu studies of physics mesurement.

in fact the mesure can be affected by the way you direc the spl meter(depends on the kind of spl meter you use), and the distance.

if the spl meter says 96 db it means that the level is 96db (if the mesure is well done).if you have this level inside, the level is the level of the speakers(93 db for exemple) + the level of the echo...the room reinforcement3 db for exemple)=96db.

so the speaker reproducing the sound of my bike in a room at 96 db should be as loud as the real bike.the difference is that if you place the speaker outdoor it would be less loud as the real bike.

it s hard to explain what i know with my poor english, i hope it s clear.

in a nutshell, a 96 db level is a 96 db level, outdoor or indoor.but to reach a 96 db outdoor you have to produce a 96db sound, indoor you may have to produce only 90dB with a speaker, the dB remaining will be "produce" by the room echo.

[edwinr]

Since my RatShack sound level meter has given me a taste, I've just bought a digital sound level meter. As an experiment I selected 'A' weighting which mimics the response of the human ear, rather than the 'C' weighting for measuring steady state noise.

Using the auto range function I played a Frank Sinatra recording and advanced the volume control of my amp so that during music peaks I was hitting around 103 to 104 db's.

Now the peaks were subjectively LOUD. The average sound level for this particular track, however, averaged around 85 to 90 db.

I understand the Klipschorns output around 104db for one watt average musical signal input. So at that amplifier volume setting I was probably using less than one watt peak power. Now I can see how SET users can drive the Klipschorns to very loud levels with just 3 to 5 watts.

[Marvel]

bclarke421,

I dug out my old book by Robert Runstein "Modern Recording Techniques" and he says most studios use 85db as the reference level for monitoring. When I have tried that on some mixes, it is almost too loud for me.

For mixing, this has to do with the Fletcher-Munson curve. Studios try to use a level that, on playback, can be at a wider range of volume levels without much apparent change in bass and treble response. Most engineers I know don't want to listen to music at these levels all the time.

Since many here spend a lot on their systems, you should check out the Rane RA-30 RTA.

http://www.rane.com/ra30.html

They come with a calibrated mic. We have the rpevious model where I work, and it comes in very handy. They can be had for around $400, give or take a few. MAybe one could be bought by a group and then rented out.

Marvel

[ben.]

Yup, Runstein was on the curriculum. Good book, IIRC. I do the bulk of my work at lower levels, but as you say, it's very important to check things out at higher SPLs to insure appropriate balances. It's all about choosing the proper compromise.

[powdermnky007]

I have a 250 2-stroke dirt bike thats been bored over that would kick anythings butt... 5th gear wheelies, plus you can hear it for about 2-3 miles cause my exhaust doesn't mount properly.

[Cal Blacksmith]

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On 7/7/2004 12:14:55 PM powdermnky007 wrote:

I have a 250 2-stroke dirt bike thats been bored over that would kick anythings butt... 5th gear wheelies, plus you can hear it for about 2-3 miles

cause my exhaust doesn't mount properly.

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I have a stock 400cc 2 stroke, lets see who puts out more hp? Stock silencer and DG pipe. It can be heard for a good mile at least.

As to music, I have an analog spl meter and when I am Rockin hard, I run an average spl of about 90 with peaks into 105. Right now, I am at peaks of about 85 db and it is plenty loud, If I open the door and go into the other room, I dround out the TV that is set at moderate levels!

[Champagne taste beer budget]

On 7/7/2004 12:14:55 PM powdermnky007 wrote:

I have a 250 2-stroke dirt bike thats been bored over that would kick anythings butt... 5th gear wheelies, plus you can hear it for about 2-3 miles cause my exhaust doesn't mount properly.

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I have a heavily modified 23 cc zenoah engine in a 46" Insane Mono R/C boat, has a nice tuned pipe, runs 60-62 mph in the right water depending on what prop I'm using, needs a slight chop for top speed to lessen the water drag. When I get my SPL meter I'll let ya know what it hits for dbl running by me at 10 feet. I will say it raps out pretty nicely, tops out at 19,500 rpm with 3.75 Hp yet the motor itself only weighs 3.24 lbs with mounts. Complete boat with full cell of gas weighs about 14 lbs. 4.32 Hp per pound. For comparison, the Ferrari Enzo is 4.97, Porsche Carrera is 5.27 and Mercedes SLR McLaren is 6.05. (As per Road & Track July 2004) I bet my boat beats em all 0-60!