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Topic: The "Voicing" of instrument amplifiers |
Keith Murrow
From:
Wichita, KS
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Posted 23 Jul 2003 10:08 am |
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| .. [This message was edited by Keith Murrow on 26 October 2004 at 04:28 PM.] |
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Bob Metzger
From:
Waltham (Boston), MA, USA
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Posted 23 Jul 2003 11:06 am
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| Controlling midrange is the whole ballgame. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 23 Jul 2003 3:50 pm
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This is kind of a pet peeve of mine.
"Voicing" is merely a euphemism for "we know better than you do what it's supposed to sound like". Where amps are concerned, they're setting the frequency response and other characteristics by design, rather than giving the user the necessary controls to do so. It does help simplify the product and keep costs down. It also protects the dunderheads who complain their violin doesn't sound right through a bass amp. 
"Voicing" in speakers usually means enhancing (by design) certain frequencies. Speaker voicing is much more critical in amps that don't have a lot of power, or amps that have limited tone-control networks.
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Ray Minich
From:
Bradford, Pa. Frozen Tundra
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Posted 23 Jul 2003 5:45 pm
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Linearity, or one out for one in, is an unreachable ideal.
The components used in an amplifier, or amplifier section, predispose that circuit/system to favor a certain signal reproductive outcome, not necessarily linear, but maybe not what the user wants either. The particular set of component values contained in an amp circuit, and their more subtle electronic & physical attributes like ESR, noise factor, geometry, material of construction, etc., all add to the mix when it comes to taking a microvolt signal and making a 10's of volts signal out of it.
I've worked with instrumentation amp circuits where the input sections to the op-amps were surrounded by guard-bands, those being little circles of circuit board foil surrounding the chip input legs to keep leakage currents from the circuit board material from affecting the signal.
I still gotta install the upgrade to my Nashville 400 that I got from Peavey last year. We'll let you know if I find guard bands.
Most favorite electronic component - 6L6GB!
Regards
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Michael Holland
From:
Nashville, Tennessee, USA
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Posted 23 Jul 2003 6:17 pm
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| The pull switches on the early Mesa amps change the amps' EQ points in a very musical way, especially the "pull deep" switch on the Mark IIC+ and Mark III. [This message was edited by Michael Holland on 24 July 2003 at 02:42 AM.] |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 24 Jul 2003 8:36 am
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My understanding of voicing as it relates to solid state steel amps, is in the equalizer section. The amplifer stages themselves are merely clean, flat amp stages. For example on the Session 400 or a Nashville 1000, the EQ is voiced for steel,meaning that the tone controls are placed at frequencies that are most useful for steel. However you can set the eq so that it's flat response (no voicing).
Then there's the issue of speaker voicing. All speakers have a "voice" as no speaker is "flat" in response. The Peavey 1501-4 is probably the most popular steel voiced speaker. The JBL 130 series speakers are also well suited for steel use.
Then there's the issue of cabinet voicing. Take for example the Nashville 400 and the Vegas 400. Both essentially the same amplifier and speaker but in differently sized cabinets. The larger Vegas cabinet which is the size of a Session or a 1000, has a deeper bass resonance thus voices the amp in a fuller, fatter way. The little Nashville 400 or the old LTD cabinets are quite small for a 15" speaker and have a tighter, smaller sound, ie. less deep bass.
So with the combination of the EQ section of the amp, the Speaker, and the Cabinet dimensions, an amp gets it's "voice."
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Brad Sarno
Blue Jade Audio Mastering
St. Louis
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Gino Iorfida
From:
Pittsburgh, Pennsylvania, USA
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Posted 24 Jul 2003 8:54 am
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Voicing also means the gain characteristics of each stage. IF you want a grittier, more overdriven tone, a common practice would be to cut some of the uber-low end on the earlier stages in order to keep the tone 'tighter'.
Voicing for a bass amp would entail extending the low end response and headroom, keeping a good bit of high end, but rolling off some of the super high harmonics to keep noise down.
When designing ANY amp, you have tons of compromises, you ahve to balance gain vs. noise, frequency response vs. noise vs. drive. The power amp you have to blance linearity vs. musical tone vs. drive/gain vs. headroom etc.
In most cases, the best tone from any amp (tube or solid state) the simpler the design the better. Look at the original Fender (tweed) champ. You have 1 preamp tube, 1 power tube, and a rectifier for the power supply. The cathode caps and coupling cap values are optimised for a balanced signal, and just the right amount of gain (in other words, enough headroom to handle hot pickups, and enough extra gain to get weaker pickups up to the full rated power of the amp). Also the simplest design amp you'll find, but also one of the best tones, and for some reason, they sound good through ANY muysical instrument speaker (from the cheap 6" speaker originally used, through a modern 4x12 cabinet etc). Tone controls? who needs them fi the amp is built RIGHT!
-- another side note, contrary to popular belief, and amps power is not rated with the volume on '10', rather is rated at the point in which the amp output section starts to break up. In other words, take the champ, rated at what, 6watts? 6 watts with a tele may have the volume knob at 3:00, with a les paul may be at 11:00, and with a pedal steel, at 9:00. Still 6 watts no matter how you look at it. After that, the output power DOES increase slightly, but less than you may think. if you maxed out the volume control on the champ with say a les paul, you may see 7 or at most 8 watts from this 6 watt amp, since the 'distortion' is more or less a compression of the wave form. |
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Mike Brown
From:
Meridian, Mississippi USA
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Posted 24 Jul 2003 10:58 am
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The term "voicing" is a "legit" term because it does come from years and years of R & D which includes listening tests, trying different voice coils, materials, etc.. The "voicing" of a speaker is what I refer to when I use this term and yes there are ways to "voice" a speaker for a musical certain application.
Years and years of experience in the steel guitar amplifier business teaches us what the parameters are of the steel guitar and also what the limitations are. I agree that manufacturers set the parameters of a product, but I would hope that most manufacturers do their R & D on a product, or they won't be in business for any length of time. It would be literally impossible to create an amplifier that had every EQ circuit imaginable, every type of speaker voicing that is available. But, the coming of the modeling amps come pretty close. |
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Ray Minich
From:
Bradford, Pa. Frozen Tundra
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Posted 24 Jul 2003 5:11 pm
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What it all comes down to is that amplifier design is as much an art as it is a science. Mother Nature is a demanding taskmaster. When you think you've got her beat one way she'll nail you from another direction. Some call it the "law of unintended consequences".
All amplifier designs involve trade-offs. In order to get something(s) good you gotta live with (or minimize) something(s) bad.
There's an interesting book available from Amazon called "The Design of High Powered Audio Amplifiers". The author does a good job of explaining some of the tradeoffs that one must make. |
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Mike Brown
From:
Meridian, Mississippi USA
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Posted 25 Jul 2003 5:19 am
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| I couldn't have stated it better. |
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