Dumb Question from Novice

[belial]

I'm embarrased to ask this, but what, exactly, is dB? I'm guessing it is more than just the individual volume level for each speaker? My SC-1 center sounds awful and someone suggested I change the dB ... Any guidelines or advice about dB? Is it just a matter of subjective preference?

[Mighty Favog]

O.k. Here's an official definition I found.

1. In re: acoustics- A numerical expression of the relative loudness of a sound: the difference in decibels (db) between two sounds is ten times the common logarithm of the ratio of their power levels.

2. In re: Electronics, Radio- a numerical expression of the relative differences in power levels of electrical signals equal to ten times the logarithm of the ratio of the two signal powers. Sometimes an absolute reference is used in the power ratio (10 to the neg. 16th power watt sq. cm in acoustics, one milliwatt in electronics and radio)

So changing the db level of the center channel may very well change the sound quality as well. It probably won't be that much different although speakers usually have different tonal qualities at different volume levels. A good example of a "db" rating is the efficiancy of your speakers. You may see a number somewhere that says something like "100db/1-watt@1meter". This means that the speaker can produce 100db of sound (loudness) using 1 watt of power to that speaker and being measured from 1 meter away from the drivers of the speaker. So one could deduce and postulate that it really doesn't take a lot of power to drive speakers loudly. Since (to me) 4 watts through a 100db speaker is painfull to say the least. All the extra power that amps and receivers tout is rarely used. I say rarely because sometimes there are explosions or extended bass notes (those use the most power) that requirer more that the avereage power being used (this is called "RMS"). So the extra power that the amp or receiver can deliver is called "headroom".

Good Luck!

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Tom

KLF-20 Mahogany

Carver Receiver MXR-150

Yamaha PF-800 Turntable/ Sure V15 Type V Cartridge

Carver TL-3100 CD

Yamaha K-1020 Cassette

dbx 1231 EQ

dbx 3bx Series Two (mothballed)

H.H. Scott 830z Analyzer

Monster Interlink 300 mk II

Original 12ga. Monster Cable

dbx 200 (mothballed)

dbx nx-40 (can't believe I still own this thing! Mothballed)

Technics R&B Series SB-7 (mothballed)

Technics R&B Series SB-3 (mothballed)

Yamaha NS-W2 (mothballed)

SAE 5000A (mothballed but perfect shape)

[ERIK]

It stands for decibel. very simply put it is a measurement of volume. In every receiver you can adjust the individual volume levels to each speaker. Due to the shape of your room or the location of your speakers some speakers may need to have their volume raised or lowered with respect to the others. My room has an no wall on the right and a wall on the left. In order to be balanced I have to raise the volume on my right speakers by 3db. What many of us do is use a disk like AVIA and an SPL meter (spl stands for sound pressure level I think).

The AVIA disk sends a test tone thru each channel separately. Using the SPL meter you can adjust the level of each speaker until the volume at your listening spot is all equal.

If one of your speakers doesn't sound right the try turning up it's level until it blends in better.

Are al of your speakers matching?

[Ray Garrison]

...after noting that there is no such thing as a dumb question...

dB is the way sound levels, or "how loud is that?" is measured. Liquids are measured in cups, pints, quarts and gallons; speed is measured in miles per hour or feet per seconds; light is measured in lumens per square meter; sound in measured in units of Bels or DeciBels (dB).

Exactly what is being measured, and how to interpert a specification like "104dB measured at 1 meter with 1 watt input" (the spec for a Klipschorn), is a lengthly but not difficult to understand topic. Here's a link that does a good job of explaining this: http://www.phys.unsw.edu.au/~jw/dB.html

When they told you to adjust the dB of your SC-1, they were saying that the SC-1 may be playing too loud (relative to the left and right front speakers), or not loudly enough. Most folks try to balance the volume levels of the different speakers in a surround setup by ear - that is, play the setup tones and listen to it. That's actually very, very difficult to do accurately. Radio Shack sells a sound pressure level meter for, uh, $30ish dollars (the analog one, NOT the digital one... the analog one is more accurate). If you get one of these, you play the setup tones on your system, and measure the volume level (in dB ) at your listening position, and adjust the output from the speakers until they're the same.

Having said all that, what is it that you're not happy with about the SC-1?

Ray

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Music is art

Audio is engineering

[decibel man]

You probably have a center channel volume control. That is the setting that changes db's or volume. Can you describe how the speaker sounds awful? Is it destorted? Does it hiss? Does it sound like it is tonally imbalanced, meaning there is no bass or no treble? We may be able to better help you with some information. That is what this board is all about.

Good luck and happy listening!

JT

[belial]

Thanks for all the information! I still get impressed by the fact total strangers will help each other out on the web like this.

It is hard to describe exactly what is wrong with my SC-1 except to say it has none of the clarity and definition of the SC-1 I listened to in the store. That speaker made it sound as if the charachters talking were right in the room with you. My speaker sounds a little tinny, almost like a cheap boombox, and the sound it produces has little "depth".

I had a Paradigm center before this and that sounded way better. Even my cheap Radio Shack "Optimus" (really RCA) towers--soon to be replaced by Klipsch SF-2s--sound better, if you can believe that.

I don't know what is wrong with this speaker, I only know it sounds nothing like the SC-1 I listened to in the shop. Messing with it's dB level did help a little, but not that much.

I think I either have to replace it with another, and hope that sounds better, or try the RC-3, even though it might not match with the SF-2s I want to buy.

Thanks again for your help--any advice is much appreciated!

[belial]

I forgot to add one thing: the sound of sheets rustling on this speaker sounds particularly unnatural for some reason, almost kind of crackley, if that makes any sense.

[Quenten]

Hey, I have the SC-1 also and also have that unnatural thing with the sheets--or at least that's what my wife says!

Just last night when she was coming to bed she got all upset and said "Now dad gum it Quenten, it's either the speaker or me...what's it gonna be!!!

Gee, why are women so moody!!!!

[belial]

Okay--you got me. No, I did not mean to suggest that I take my center speaker to bed with me. The sound of the sheets is not actually ON the speaker, it comes THROUGH the speaker, when there is a scene in a movie involving sheets. And no, I do not watch an awful lot of movies with scenes that involve sheets, it just so happens that this one, perfectly respectable movie, had a scene that did involve the sound of rustling sheets, which, as I have previously stated, sounded somewhat "crackley".

Now can someone help me? I mean with my center speaker?

[Mighty Favog]

Good save.

[Pete C]

>I listened to in the store. That speaker made it sound as if the charachters talking were right in the room with you. My speaker sounds a little tinny, almost like a cheap boombox, and the sound it produces has little "depth". <

Possibly, your amp is bad and you didn't notice it with the inefficient speakers. I would carry your speaker back to the store and have the salesman hook it up for an A/B comparison. If they sound the same, it may be the store's setup that "colored" the sound. Your amp or setup may need fixing.

[belial]

Thanks Pete C. I don't think it is my reciever, mostly because the Paradigm center I had, roughly the same price as the Klipsch, sounded pretty damn good ... I think I'm just going to send it back and ask for a replacement, or upgrade to the next level Klipsch center ...