Why do guitar amps never have the design considerations of hi-fi speakers?

[Jazz P Bass]

I think the OP needs to redefine 'guitar amplifier'.

The actual 'sound' of different amplifiers is actually in the preamp section.

[Mike Sulzer]

I think the OP needs to redefine 'guitar amplifier'.

The actual 'sound' of different amplifiers is actually in the preamp section.

??? Output stages do matter.

[nevetslab]

I think the OP needs to redefine 'guitar amplifier'.

The actual 'sound' of different amplifiers is actually in the preamp section.

Plus the 'sound' of overdriving the output stage and the speakers into natural break-up. Do that on a 'hi-fi' type speaker cabinet and they sound horrible. Horn drivers sound like kaka overdriven! Sure, you can connect a Marshall amp to a good PA speaker...have to search for any that use passive crossovers these days....but you'd never get the tone as you would with selected '12's in the 4x12 cab's. All that comes together to create the 'sound'. It's Raw energy....not processed and dynamics-limited recordings.

[Chuck H]

I think he was just saying that WRT output stages, well they aren't all that different from any other amplifier. But with that in mind I'd say that the preamp and the speakers chosen for guitar amplifiers are the primary differences.

Ok... With a caveat. When you consider that any real difference in power amps as they are related to guitar tone, well then you have to consider that they are likely to be clipped. And with more or less or zero NFB. And NOW you have a much greater difference and contribution from the power amp.

[Old Tele man]

Because:

HiFi's do NOT have "fuzz" or "distortion" buttons...but Guitar Amps (and their pedals) do.

[Chuck H]

I think I would want to build an amp circuit that DOES reproduce the string vibrations as accurately as possible, and then send that amplified signal into a speak cabinet that WAS designed to reproduce that signal as accurately as possible. And then... use things like EQ, filters, and even intentionally designed speaker baffles to "color" the sound of my amp to sound like... well... however I want it to sound?

This is a noble goal. It's been at least partly undertaken by digital modeling technology, though the speaker cabinets for these amps are about the same as guitar amp cabinets have always been and the speakers used are only slightly higher fidelity than typical guitar amp speakers. But the idea is the same as yours. Build a processing system that can handle ANY guitar tone and then EQ accordingly for what goes into the system. It just turns out that for the most useful guitar sounds really high fidelity isn't necessary. Which is why...

The same old amps that were made by Fender and Marshall still hold up today. And not even as limited in range as one would think. But if what you want is an amp capable of covering all the known, relatively good tones AND able to color really far outside of the lines too then you're on the right track. It just happens that getting that far outside the norms for guitar tones hasn't been useful enough for anyone to consider building such a thing commercially. But, anyway, this is why "guitar amps never have the design considerations of hi-fi speakers".

[Helmholtz]

??? Output stages do matter.

^^^That! Just think of screen compression and the complex interaction between tube output stage and speaker impedance. These effects are audible even before powerstage clipping.

[g1]

I think if the OP would just plug an electric guitar into his home hi-fi system, we would not be having this discussion. It is something best heard to understand.

[loudthud]

One thing not mentioned in this thread so far is those things sold by Bose. There is a bass box on the floor and pole like structures with many small driver. They claim you sound the same at any place in the room. Other companies make similar systems as PA systems, notably EV. The idea must be that you get all your tone from a preamp or pedals, I don't think you want to drive a pole speaker with a Marshall tube amp.

Just a plug; you think tubes amps sound good for guitar ? Vocal harmonies sound wonderful through a tube PA.

[Dolmetscher007]

I think I am finally getting what you guys mean. I'm starting to see that my "tell me exactly how and why things work the way they do" is going to cause a few of you guys to get frustrated with me. Have patience my brothers; I am just a huge science fan that happened to learn how to play the guitar 25 years ago.

So what you guys are saying is... if someone did design a guitar amplifier that could take the exact signal (within reason, of course, since it is analog) and preserve as much of it's fidelity as it is being amplified, and then recreate it using tweeters, woofers, and crossovers... it would sound bad. I guess I can understand that. I guess the 35mm vs. super HD video analogy does pretty much represent the same idea. 35mm film is like a tube amp... it became the norm, because it's awesome. Sure you can always go further, get more, sharper, faster, whatever... but in the end, the HD video folks end up running all kinds of software plugins and effects to "make it look more like film."

The main reason why I started this post, believe it or not, had less to do with crossovers and tweeters, etc... and more to do with the speaker box design. I am starting to look into thinking about dimensions for a 2 x 12" combo amp. So naturally, I start looking at Twin Reverbs, AC30's, etc. and I am wondering if these boxes are literally just a means to hold in the speakers, or if the dimensions (height, width, depth, upward speaker angle etc.) actually have a dramatic effect on the overall sound or not. I know that sound guys just stick an SM57 in front of one of the speakers when we play a show. So I imagine not. But I was hoping to get some tips.

[Justin Thomas]

We had one of those Bose thingies in one of the churches I played in. You DO sound the same every where in the room: LOUD, shrill, strident, brittle, and generally like butt-ass-crap.

I ran a friend's vocals through my Spitfire clone feeding a 4x10 CL homemade cheap seaker tower once. Our acoustic player didn't realize he was going through a PA. <THAT> is a successful PA. And every single keyboardist I run through one of my old Fenders says they like the sound better.

My conclusion? Tubes sound better for EVERYTHING. Period.

Justin

[The Dude]

Box design does matter. There is an audible difference between an open back and closed back cabinet. So, nobody's saying it doesn't matter. The point is that box porting and volume is not as critical because there isn't that much low frequency or sub content. As an example, I once read that the Marshall 4x12 cabinet was designed for the least amount of wood waste and it's dimensions had little to do with Thiele/Small parameters.

[nosaj]

We had one of those Bose thingies in one of the churches I played in. You DO sound the same every where in the room: LOUD, shrill, strident, brittle, and generally like butt-ass-crap.

I ran a friend's vocals through my Spitfire clone feeding a 4x10 CL homemade cheap seaker tower once. Our acoustic player didn't realize he was going through a PA. <THAT> is a successful PA. And every single keyboardist I run through one of my old Fenders says they like the sound better.

My conclusion? Tubes sound better for EVERYTHING. Period.

Justin

Yess,,,, but could you kill small rodents within a 50 yard radius of my practice building

nosaj

[Chuck H]

So what you guys are saying is... if someone did design a guitar amplifier that could take the exact signal (within reason, of course, since it is analog) and preserve as much of it's fidelity as it is being amplified, and then recreate it using tweeters, woofers, and crossovers... it would sound bad.

Nope. What we're saying is that if you plugged a typical guitar amp into woofers, tweeters and crossovers it would sound bad (subjectively) and is totally unnecessary at the instrument amp end of things. But recreating guitar sounds through woofers, tweeters and crossovers is done all the time on hi fi audio systems and sounds just fine.

[g1]

I think one of the top considerations for most manufacturers as far as cab design went was mobility.
The customer base was musicians, and they needed something to take to the job.
If you don't keep this in the forefront of your thoughts, I can see how you might be scratching your head about such 'lo-fi' cab designs.