Bought a Radioshack SPL meter and

[laurenc319]

I suprised myself with the reading levels when I play music.

First the noise floor in my home is low, less then 50 db ( the meter only reads down to 50 )

In my 24X14 foot LR with the Forte I's with the Cary SLI-80 in

the afternoon, I find 70 to 75 db at 12 feet away from the

speakers which is about average listening level for

jazz. What I thought was loud was 82 to 85 db. I played some hard

rocken stuff ( Eric Johnson, Alien Nation CD) as loud as I could

tolerate and the levels were 95 to 98 db at the listening

position and 104 to 106 db 3 feet from one speaker.

In the rec-room with the Cornwalls and Wright mono 3.5s the levels were

also 73 to 75 db for jazz 14 feet away from the speakers. With the

Wrights I 'm using nos RCA 's dual plates. Anyone

have experience with other brands of nos 2A3's ?

I guess most of the time I'm using a lot less then 1 or 2 watts. So the amps are loafing most of the time.

The Cary amp can run KT-90, KT-88s, 6550s, El-34 and 6L6s. Presently I

have JJ KT-88s installed. I always wanted to try the 6L6 sound

but was hesitant because the power of the amp is 30 watts in the

ultralinear mode as compared to 80 with the KT-88s. Anyone have a

recommendation for a good 6L6 new production or nos ?

thanks

Larry

[Allan Songer]

103 db at 3 feet is LOUD. Why anyone would want to listen to ANYTHING louder than that coufuses the heck out of me!

Here are some 6L6 tubes on ebay that will put a but, fat smile on your face:

http://cgi.ebay.com/Western-Electric-National-Union-350B-tubes-quad_W0QQitemZ7373900829QQcategoryZ73381QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[edwinr]

I was reading an interesting article in 'Hi-Fi world' magazine, recently. This article stated that spl levels fall away very quickly as you increase listening distance - approximately 6db for every doubling of distance. For example, if we measure 86db at 3 feet from one speaker, increasing this distance to, say 12 feet, the spl at our listening postion would decrease to 74db - which is barely above a hushed conversation. Adding a second channel would give us an extra 3db, so our listening level would increase to a more reasonable 77db.

But to listen at loud levels - 100db, you would need an extra 23db of spl. To attain these levels you would need a minimum of a 100 watt per channel amplifier driving a speaker capable of outputting 86db at 3 feet for 1 watt of input. For every 3db increase in spl, you will need to double your amplifier power.

The best way to get big spl's in large rooms is to increase the number of loudspeakers e.g. a surround sound system or a multi channel music system. This contributes to a smoother, more even spread of sound, rather than two front loudpseakers churning out big spl's. But then forum members who work in sound reinforcement and big spl's would be familier with this idea anyway.

For those that prefer low powered amplification, sitiing closer seems the obvious solution. Also closed box rooms seem to reduce the loss of absolute spl's, rather than listening in more open rooms.

[DrWho]

103 db at 3 feet is LOUD. Why anyone would want to listen to ANYTHING louder than that coufuses the heck out of me!

Seems you haven't been to the symphony very often (yes, one of those fancy places where you have to dress up to listen to live music)...In the back of the auditorium they will be pushing 110dB levels with a FF. FFF is about enough to make you go deaf, but I love every minute of it...

I won't mention rock concert levels, though that would be another just as valid argument.

We're supposed to emulate actually 'being there'

[Parrot]

Yes, but in jazzworld, patrons like to be able to order drinks and talk

above the background music. It's a whole different thing.

[laurenc319]

hi,

Yes I've go to both, jazz clubs and classical symphonies. The

sound levels in a concert can reach amazing levels. In mostjazz

clubs you can carry on a conversation. For rock concerts, I

bring ear plugs.

Larry

[pauln]

I have mentioned elsewhere that the SPL meters can be misunderstood. When you set it on 'peak' it is summating the energy more quickly than the 'average' setting, which summates slowly. According to PWK himself, the peak setting was timed to be best for measuring male announcer voice. The true peak is 13dB higher. When your meter set on peak hits in the high eighties the true peak is more like 100dB.

[Allan Songer]

103 db at 3 feet is LOUD. Why anyone would want to listen to ANYTHING louder than that coufuses the heck out of me!

Seems you haven't been to the symphony very often (yes, one of those fancy places where you have to dress up to listen to live music)...In the back of the auditorium they will be pushing 110dB levels with a FF. FFF is about enough to make you go deaf, but I love every minute of it...

I won't mention rock concert levels, though that would be another just as valid argument.

We're supposed to emulate actually 'being there'

I attend concerts at Disney Hall on a REGULAR basis--I'll be there again on Jan 8 when Mehta conducts Bruckner's 8th. There is NO way that there are SUSTAINED sound levels anywhere NEAR what you state--brief, tansitory peaks--YES, but the average level is well below 100 db even in the front of orchestra seats.

Ask GaryMD and boomac about my Disney Hall seats.

[PrestonTom]

Two comments.

First, the of 6dB per doubling of distance is only true in a free-field environment. That is in the absence of reflecting surfaces. In a living room, the drop off will be much less and it will also be frequency dependent.

Second, the issue of symphonic music being well-over 100 dB is misleading. It is certainly not at this level for a sustained period. Additionally, a dB number by itself is not very informative. It is a function of the bandwidth (and if or how it was weighted) and also if was integrated.

That is why these measurements should not be take to seriously. The details that went in to the measure are critical and are typically not well understood by the reader.

Good Luck,

-Tom

[Rivendell61]

Yes the highest SPls are peaks--which will not be of long duration. But presumably--in the ideal system--we do not want to have them lost (clipped, compressed) in playback.

FYI--here are some numbers taken from audience positions (from a bunch of performances) with a peak SPL meter:

Classical music: 90-118 dB SPL

Jazz: 114-127 dB SPL

Those were published by Fielder in JAES

Most amps have a 1-3 dB 'headroom', and there will be some compensating room gain of a few dB, mainly in the lower frequencies.

Home noise floor does not really exist as a 'floor'--so potential audible range is really quite large.

Mark

[edwinr]

I guess this article was referring to musical 'peaks'. To maintain and listen to average 100db levels at a distance of 12 feet would be intolerably loud.

[Allan Songer]

127 db in a JAZZ performance? LMAO!!!!

That's right at the threshold of pain.

A CHAINSAW at 3 feet is 105db

A jet aircraft taking off is 120 db at 250 ft.

A train horn at 5 feet is 130db --ever heard a train horn up close?


But a group of musicians playing essentially acoustic intruments peaks at 127db?

[Rivendell61]

Allan,

It is surprising how loud acoustic actually can be.

And much louder than 127 dB if you are on stage.

Drums (acoustic) can be 138 dB SPL peak standing next to them (3 feet). Trumpets louder.

The numbers I was quoting are an attempt to quantify needed system dynamic range for listening to a performance -- so are measured from the audience.

Also....your examples are continuous (jet engine, chain saw, etc), while these are measured peak levels which can be very 'transient'.

Mark

[DrWho]

Well last I checked there are many pieces of music that sustain a FF for long periods of time, and it really is almost always around 110dB. The opera is even louder and the thing that amazes me is that opera singers can sustain 120dB without amplification! Again, I know because I'm recording (and sometimes mixing) live symphonies all the time. Heck, I used to play in them too....and I would bring my SPL meter on stage with me just for fun (during practices).

On stage standing in front of a brass section it wouldn't be uncommon to measure levels of 126dB with a FFF. These are not transient millisecond peaks....it's a long continuous note.

It's interesting to note that these insanely loud levels aren't faitiguing or even damaging to the ear when they are a clean uncompressed signal. But the second you try to play an electric instrument or rock music at these volumes it suddenly becomes most unbearable.

Since chain saws were mentioned....I was at a concert in Germany where they were using a chainsaw as an instrument during one part. They had to mic the bloody thing because it naturally wasn't loud enough to compete with the rather small orchestra (~20-30 people).

[D-MAN]

The point that everyone is seemingly forgetting is that ONLY CERTAIN frequencies are going to be that loud - cymbals, kick-drum, etc. and that generally for short durations. Entirely possible for a jazz enemble to hit some peaks, but not sustained, of course. Also conisder the proximity factor - small "intimate" groups will be louder just by proximity to the listening position. Large orchestras are going to be further away.

I've never met a drummer that could play "soft" (or now that I think about it, a singer that wasn't egotistical, but I digress)...

Where you have broad spectum frequencies at a high SPL, then you got something. Sustained high-SPL levels are damaging to the hearing.

If its 40 Hz bass and its 115db - cool. If its 15K at 115, bad.

DM

[michael hurd]

Some people can't grasp the difference, a pure tone or a limited bandwith note will sound much much louder than it actually is, especially in the region where the human hearing is most acute.

For example, a smoke detector seems pretty loud, but most are 85-90 decibels measured at a distance of 10 feet. A bass drum transient at 90 db is not perceived to be as loud, but it is much lower in frequency.

[cwop]

127 db in a JAZZ performance? LMAO!!!!

That's right at the threshold of pain.

A CHAINSAW at 3 feet is 105db

A jet aircraft taking off is 120 db at 250 ft.

A train horn at 5 feet is 130db --ever heard a train horn up close?

But a group of musicians playing essentially acoustic intruments peaks at 127db?

You're absolutely right, the aforementioned levels by the poster are absurd.........Trains horns? I live in the country and step out my back door (not too much building reflection) and quite frequently get 65dba (ANSI type11 SLM) when that big ol' 3 trumpet Leslie airhorn blows at slightly over a mile away. Try one of those in a jazz club or concert hall!! Ouch!

[michael hurd]

This might help explain a few things. This is a picture of the Fletcher-Munson equal loudness contours. For those that are not familiar, the human ear does not hear all frequencies equally. We do not hear low frequencies well at low sound pressures, compared to frequencies that are normal in speech.

[michael hurd]

When you invert the curve, you can see what we hear as opposed to the original curve, which shows how much more spl is required at some frequencies in order to be perceived to be the same volume as the frequencies where the ear is most sensitive.

[mobile homeless]

This might help explain a few things. This is a picture of the Fletcher-Munson equal loudness contours. For those that are not familiar, the human ear does not hear all frequencies equally. We do not hear low frequencies well at low sound pressures, compared to frequencies that are normal in speech.

Hence the invention and use/misuse, of the loudness/contour button and/or knob (ie Yamaha) seen in many receivers and integrateds, this to aid in low volume listening. Some did this feature far better than others. It was supposed to roll out as the volume increased. Early Yamaha gear recommended using their "contour" feature as the main adjustment after setting a basic "volume" level. I've never been a big fan due to the rather coarse nature of most, not to mention the addition of yet another switch. NAD was pretty subtle with their implementation.