I recently bought a Peavey VIP 1 combo modelling amp to replace a 30 year old Laney Linebacker 30 transistor combo amp that has hardly been used.
The modelling amp is much much brighter for all the amp simulations than the old Laney amp, so much so that I thought the the Laney must be broken in some way.
Today as part of the investigation I played pink noise through both amp heads into the same 10" speaker in the Laney cabinet. I did the same thing with a normal hifi amp/speaker and used the totally uncalibrated microphone in my computer, and the uncalibrated microphone in my mobile phone to do uncalibrated FFT plots.
Wow what a difference. The computer, the phone and my ears basically agree that the modelling amp has a 25 dB peak between 1 and 3kHz, whereas the Laney is actually reasonably flat, as in not so different from a normal hifi amp/speaker, at least over the frequencies generated by an electric guitar.
So what's up, is the new modelling amp working the way it's supposed to? Is the Laney defective?
The modelling amp is much much brighter for all the amp simulations than the old Laney amp, so much so that I thought the the Laney must be broken in some way.
Today as part of the investigation I played pink noise through both amp heads into the same 10" speaker in the Laney cabinet. I did the same thing with a normal hifi amp/speaker and used the totally uncalibrated microphone in my computer, and the uncalibrated microphone in my mobile phone to do uncalibrated FFT plots.
Wow what a difference. The computer, the phone and my ears basically agree that the modelling amp has a 25 dB peak between 1 and 3kHz, whereas the Laney is actually reasonably flat, as in not so different from a normal hifi amp/speaker, at least over the frequencies generated by an electric guitar.
So what's up, is the new modelling amp working the way it's supposed to? Is the Laney defective?
That does NOT sound right.
It does not sound like something a speaker, or normal tone controls, would/could do.
Is it maybe a mis-setting in the too-smart digital processor?
I would expect a "guitar amp" to be flat from 1KHz down to 200Hz, and then more or less fall-off to 50Hz depending how much cone-area you bought. Above 1KHz it is typical to have a 5dB rise above 2KHz, and then a *sharp* cut-off by 5KHz. W-i-d-e variations are possible with tone and speaker. But not a 25dB mesa.
One of my favorite free internet things is the Tone Stack Calculator from Duncan Amps:
TSC
It is a free bit of software, easy to use, and intuitive. It shows a variety of common tone control circuits with graphic frequency response curves. You can vary the high/mid/low controls in real time and see the changes in real time. You can even change component values to see the changes. Change that 250pf treble cap to 400pf for example.
It is interesting and lots of fun.
Duncan has other nifty things on his web site. The power supply designer is useful.
TSC
It is a free bit of software, easy to use, and intuitive. It shows a variety of common tone control circuits with graphic frequency response curves. You can vary the high/mid/low controls in real time and see the changes in real time. You can even change component values to see the changes. Change that 250pf treble cap to 400pf for example.
It is interesting and lots of fun.
Duncan has other nifty things on his web site. The power supply designer is useful.
Noted on DIY Stompboxes forum....
"Jarmo and ~arph made a browser friendly version of Duncan's Tone Stack Calculator: ..."
TSC in the web
"Compared to the original TSC, the sweep feature and some other (minor) things are still missing from the web-implementation. It would need some better layout for mobile devices as well. Hopefully the undersigned (or some other volunteer) will add these (and maybe more) features later on. The development files are shared in GitHub: GitHub - jatalahd/tsc: TSC in the web "
I can offer one subjective experience: I have a Digitech Trio+, a guitar pedal that, among other things, generates a synthesized drum track for you to play along with.
The Trio+ is designed so you can send the drum track straight into your guitar amp (along with the guitar signal). But if you happen to have a P.A. or other flat-response amp around as well, the Trio+ allows you to send the drums to the flat-response amp instead of the guitar amp.
When I tried this (using a wedge-shaped acoustic guitar amp as the flat-response one), the difference in the perceived quality of the drums was huge. They went from sounding extremely fake and unimpressive, to sounding quite good and much more realistic.
It's always hard to describe the difference between sounds, but, fed to the flat-response amp, the drums had more kick, and also sounded tighter and crisper.
I would guess these audible differences correspond to a flatter and more extended bass response from the flat-response amp. A flatter frequency response comes with better transient response as well.
In the case of a Fender electric guitar amp, we know flat response was never a goal: Leo's "tone stack" famously carves out a huge notch in the midrange. Add to that the weak bass response of an open-back cab, and the numerous mid-range internal acoustic resonances of said cab (which can often be detected by your ears as a "boxy" sound.)
-Gnobuddy
Crickets have ears in their (front) legs: ( The insect that hears like a human, with ears on its knees - Not Exactly Rocket Science : Not Exactly Rocket Science )
Maybe crickets came up with the traditional way we position our guitar amps?
-Gnobuddy
The resonances we're talking about are set mostly by the distance between parallel internal walls of the box, and the speed of sound in air. ( Standing Waves – The Physics Hypertextbook )
If there are two infinitely large parallel walls a distance L apart, there will be a resonance at the frequency f = v/(2L), where v is the speed of sound in air. Then there will be a second resonance at twice this frequency, a third resonance at three times this frequency, and so on - a whole array of resonances, all spaced apart in frequency by the same amount, extending through the entire frequency range.
That sounds bad enough, but two walls isn't enough to make a box - we have to add one more set of parallel walls to close off top and bottom, and that pair will come with their own set of resonances.
And then we have the front and back of the box to deal with as well. If we only close the front (like most old Fender combo amps), the back is open, and we've created a sort of short, fat, organ pipe: which, unfortunately, comes with its own set of infinitely many resonances.
And if we close the back as well, things are no better: we are back to having two parallel walls now (front and back), so once again, we get an infinite number of resonances, all equally spaced.
If the walls aren't parallel and flat, the mathematics gets more complicated, but the end result is still an infinitely large number of resonances, though they may not be equally spaced apart in frequency this time.
Evolutionary history has given our ears and brains the ability to pick out these arrays of resonances, and so tell when we're inside a box (probably very useful if you live in a cave, or go hunting for prey inside one.)
So when you walk into a tiled bathroom, not only your eyes, but your ears too, can tell you're in a small enclosed space with hard walls all around you.
Unfortunately for us, the same problem affects our loudspeaker boxes. Have you ever put your head into an empty bucket, and noticed how weird ambient noises (or your voice) now sounds? That's the effect of all those internal resonances at work. Now imagine you put a loudspeaker in there instead of your head - the same thing happens to the sound from the speaker.
For decades now, Hi-Fi speakers have used some sort of acoustic treatment (fibreglass, acoustic wool, et cetera) inside them to reduce the strength and number of resonances. And electric guitar amps? They continue to ignore the basics of acoustics. I only know of one brand (Fuchs - Guitar Amps, Boutique Amps, Tube Amps, Pedals, Bass ) that uses acoustic stuffing inside their guitar combo amps and speaker cabs.
In my experience, no. The Fish-n-Chips can tweak out one or maybe two resonances, but a speaker box can have dozens of them.
Stuffing a boxy-sounding speaker enclosure with some sort of sound absorbent material - I've used cheap pillows from Walmart - can help, to a degree. (But combo valve amps need cooling airflow, so be careful not to block that!)
If a speaker box happens to have unfortunate dimensions, some of the various resonances can fall right on top of each other and become even stronger, and this can sound really nasty. I find cubical (or near-cubical) speaker boxes usually sound very "boxy", and long skinny boxes sound awful as well, like speaking with a mailing-tube held up to your mouth.
Like many things in audio, it seems to be quite subjective how much the "boxy" sound bothers any particular person. VOX sold lots of their little re-issue AC4-TV amps a few years ago, but only a percentage of buyers found them unbearably boxy (they had a nearly cubical shape.)
-Gnobuddy
^^^ Agree.
I assume a Spanish acoustic guitar is shaped and has a sound hole to give resonances that enhance the sound of the guitar.
Has anyone tried a guitar speaker cab of that size and shape? - might look a bit weird though!
I think a small speaker would need to go where the bridge normally goes and the sound hole would be left open as a 'port'.
I assume a Spanish acoustic guitar is shaped and has a sound hole to give resonances that enhance the sound of the guitar.
Has anyone tried a guitar speaker cab of that size and shape? - might look a bit weird though!
I think a small speaker would need to go where the bridge normally goes and the sound hole would be left open as a 'port'.
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Something like this?
An externally hosted image should be here but it was not working when we last tested it.
Sure, why not for fun.
But keep in mind the guitar's job is to create the sounds and all those resonances and stuff are part of creating the original sound. A speaker is designed to reproduce sound, not create it from scratch. the guitar takes mechanical movements and translates them into sound, while a speaker takes an electronic signal and converts that into sound.
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