Anyone clone a guitar cab??

[006]

XeS, that's exactly my point. I think since it would be nearly impossible, or rather just dumb, for Mesa/Orange/Marshall/Etc. to have a cabinet tuned for every guitar tuning that people use it would go to show that really any cabinet will work, regardless of dimensions.

However, I think having a cabinet that responds to your specific tuning can actually help a lot with definition and really having the right power behind your tone. Otherwise why would people go to the rediculous trouble of tuning the cabinets in the first place? From all of the research, it actually is a significant difference *BUT* since an "untuned" cabinet you can buy (Mesa/Marshall/Etc.) sounds good already, I personally don't know how much of a difference it would make, and if it would be worth the difference to me. Who knows, maybe it's one of those killer secrets to tone...or it could be wasted effort.

I'm half-curious to find out if tuning a cabinet makes a difference myself, but I would have to build two identical cabinets with four identical speakers (2 in each) and have one designed (on the inside) to be tuned to a specific tuning for my guitar, and the other to be just a normally engineered cab. When looking at all of the data you have to get from the speaker and the design and then calculate and process that data....bleh. I hate math to begin with!

It seems more of a novelty as I go on thinking about it. And the old saying, "if it ain't broke, don't fix it", comes to mind.

~e.a

 

[Metaltastic]

How would one "tune" a cab, anyway, just theoretically?

 

[006]

Theoretically it involves measuring the response of the speaker using a sine wave of the frequency you wish to tune to. For example, *say* C standard does like, 50Hz or some shit...each tuning (note) has a specific frequency it correlates with. So, you would tune the cab, typically by internal design, to handle that specific frequency better than an un-tuned cab could.

I don't know the specifics of the design measures, but I know it involves making the cabinet's innards a specific size, for the correct air space involving a certain frequency. That's about as much info as I could find on it. If you want to see all of the calculations and data retrieval that is involved, check out kbapps.com and look for the calculator...it's insane.

I've been looking around, but I have yet to find anything that goes over possibly converting a cab you may already own into a tuned cabinet. I would imagine it's as simple as building a box within a box, since most cabs have a back panel that comes off revealing the entire insides.

~e.a

 

[006]

Here are a bunch of the formulas, to give you an idea of how batty this process is...

Driver Parameters

Ro = Rmax / Re

Rx = Re * ( Ro )1/2

Qms = Fqr * [( Ro ) / ( F2 – F1 )]1/2

Qes = Qms / ( Ro – 1 )

Qts = Qms / Ro

Sd = 3.14159 * ( Dia / 200 )2

Cms =
[ 1 / ( 12.56636 * ( M / 1000 ) ) ] * [ (Fqr + Fqs) * (Fqr – Fqs) / (Fqr2 * Fqs2) ]

Vas = 140000000 * Cms * Sd2

EMP = Fqs / Qes

L = X / 6283.18 X = ( R2 – Re2 )1/2



Sealed Enclosures

Qts = Qes * Qms / ( Qms + Qes )

Fcb = Fs * [ ( Vas / Vb ) + 1 ]1/2

Qtc = Qts * [ ( Vas / Vb ) + 1 ]1/2

db = 20 * log10[ Qtc4 / ( Qtc2 – 0.25 ) ]

Fdb = Fcb * [1 – ( 1 / ( 2 * Qtc2 )]1/2

F3 = Fcb * [ ( a + (a2 + 4)1/2 ) / 2 ]1/2
a = [ 1 / (Qtc * Qtc) ] – 2

And here is a good quick page on some basic enclosure building tips. Such as, mounting the speakers on the outside, etc.

Parameters of a driver

You will need an audio sine-wave generator, frequency counter, ac voltmeter, 1000 ohm resister, a 10 ohm 1 % precision resistor, and the driver to test.

The test setup for measuring driver impedance is shown here. Connect everything as shown.
Set up diagram

First, calibrate by inserting the 10 ohm resistor in place of the driver.

Adjust the voltage output of the audio frequency sine-wave generator until the ac voltmeter reads 0.01 volts.

Replace the 10 ohm resistor with the driver to be tested.

Keep the output voltage constant. 0.01 volts represents 10 ohms, 0.015 volts represents 15 ohms, etc.

Vary the frequency control of the audio frequency generator to find maximum resistance ( Rmax ). At that point, frequency is resonant frequency ( Fs ).

My brain is going to explode now...

~e.a

 

[Metaltastic]

Haha, consider me intimidated and dissuaded, but thanks anyway e.a.!

 

[006]

Lol me too. It think a normal cab will do just fine!

~e.a