A real (acoustic) guitar is very directional also.
Part of "the sound of the source" (instrument) is the directivity.
The usual guitar speaker designs *work*, at least over the center of the ball-room.
If you want all-over sound (you rarely do outside the home), mike the cabinet and feed it to good modern PA speakers. The best will hit every seat with near-equal sound. (This rarely happens outside BIG venues and mass-cluster PA systems.)
Part of "the sound of the source" (instrument) is the directivity.
The usual guitar speaker designs *work*, at least over the center of the ball-room.
If you want all-over sound (you rarely do outside the home), mike the cabinet and feed it to good modern PA speakers. The best will hit every seat with near-equal sound. (This rarely happens outside BIG venues and mass-cluster PA systems.)
Very true, as anyone who has tried to mic one knows.
In recent years, some acoustic guitars put the sound hole on the top of the guitar, rather than the front. This lets the player hear the "good tone", rather than the audience. That's probably a nod to the fact that plenty of acoustic guitars are played alone at home, with no audience.
Maybe, but IMO it is a bad part of the "sound of the sound". Why not improve it if we can?
I think this worked better in ye olde days, when guitarists preferred warmer tones with less high treble to beam like a laser. The very bright tones used today by may country / folk / pop guitarists suffer a lot more from noticeable tonal variation depending on where the listener is located.
Personally, most of my guitar playing these days is at jams and song circles. Everyone sits on the periphery of a large circle. And this configuration immediately reveals major problems with guitar amp directivity - whichever way you face the amp, and wherever you place it, the majority of people get poor sound.
Granted, "sound in the round" is an issue with any conventional speaker system, not just guitar amps. But the little P.A. I use for vocals has enough dispersion to produce reasonably good sound for at least half the people sitting in the circle. Both my Fender amps are much worse at this.
I used to use two back-to-back wedge speakers in the center of the circle for vocals, which did a better (but still imperfect) job of providing sound to everyone. One of those speakers didn't make the move to Canada with me, though.
I think there is a good case for a wedge-shaped guitar amp with one speaker facing forward on the front panel, and one speaker facing backwards on the rear panel. The guitarist can place the amp in front of himself/herself, and still have some chance of hearing himself/herself. It's got to be better than the usual "amp behind you on the floor, pointed at your calves" scenario!
-Gnobuddy
If you don't mind wading through the snake oil, there's a number of HiFi speaker architectures which address this issue.
The various pyramid (and cubic) shaped B&O speakers are omnidirectional, some with a single, vertical firing tweeter hitting a wave guide, some with a purality of drivers with overlapping dispersion areas.
None are cheap
Hi Gnobuddy! Thanks for your analysis.
By 'direct musical communication', I was thinking not so much of the physics of the communication as of the emotion of the communication - the amp and speaker being symbiotic parts of the musical instrument known as the electric guitar.
Not all good Hi-Fi speakers use a crossover network - Quad electrostatics anyone?
I worry that a passive crossover in a guitar speaker cab would introduce 'ringing' with its consequent deleterious affect on transient response and hence on the attack and decay of guitar notes.
Afraid I'm not a big fan of passive crossovers per se!
By 'direct musical communication', I was thinking not so much of the physics of the communication as of the emotion of the communication - the amp and speaker being symbiotic parts of the musical instrument known as the electric guitar.
Not all good Hi-Fi speakers use a crossover network - Quad electrostatics anyone?
I worry that a passive crossover in a guitar speaker cab would introduce 'ringing' with its consequent deleterious affect on transient response and hence on the attack and decay of guitar notes.
Afraid I'm not a big fan of passive crossovers per se!
Ringing? Part of the reason the 5E3 Deluxe sounds like it does is the lightweight baffle and it vibrating. I think the whole idea of a guitar speaker built like a hifi speaker misses the point. The guitar speaker colors the sound in a good way. Just spread it around some.
Speakers don't know emotion, only F = q (v x B), the force on moving charges (electrons) in a magnetic field. So the only communication between amp and speaker is electrical. If that doesn't change, there has been no change in communication.
The guitarist certainly does have emotions. Yes, if he/she believes crossover networks are evil, it could certainly influence his/her playing, and lead to worse sound. But the fix for that isn't electronics, it's education and/or therapy! 😀
...a wonderful invention, and by all accounts, a huge step forward when first invented. As musical tastes changed and people were unsatisfied with the limited bass extension and power from the Quad electrostatics, they were frequently bolstered by a subwoofer or conventional woofer, and a crossover network...which made them sound better.
Have no worries: the mathematics of the Fourier Transform ties together frequency response, and transient response. One completely predicts the other. A happy frequency response equals a happy transient response.
As an aside, a big heavy 12" or 10" guitar speaker has very poor transient response - and this shows up as the usual midrange peak and steep rolloff in the treble response of the guitar speaker. Fourier's marvelous transform doesn't lie, a crappy frequency response equals a crappy transient response!
One more thing, and this last one is subjective, and only my opinion: I believe that for an electric guitar to sound good, the sharp initial transient actually has to be "squashed" substantially, which happens automatically in valve guitar amps because they are quite nonlinear. Inexpensive solid-state guitar amps, on the other hand, use op-amps and chip power amps, which are quite linear, precise, and accurate, and do not squash transients - and they always sound horribly harsh as a result.
They are certainly much harder to get right, no doubt about it. It's also true that the off-the-shelf crossover networks from Parts Express (or designed from the simplistic formulae in every speaker design book) are horrible, and work nothing like the textbook predictions.
But, until quite recently, bi or tri amping was very expensive. Which means the vast majority of the best speakers of the last fifty or sixty years all used passive crossover networks. (The transformer that drives the Quad ESLs has inductance and capacitance too, just like any passive crossover network.)
The speakers I use for all critical listening are a pair of Alesis Monitor One Mk IIs (paired with a Velodyne subwoofer). These Alesis monitors were designed for critical listening by studio engineers while recording and mixing, and they are certainly the most accurate speakers I've heard in their price class. And they use a passive crossover network - they were designed just before the time when active crossovers became a major marketing trump-card in monitor speakers.
I knew two of the engineers behind the design of this particular Alesis speaker. They had a $5000 Bruel and Kjaer measurement microphone with a flat response from below 5 Hz to above 40 kHz. The also had two different computerized frequency response measurement setups (Audio Precision System One, and MLSSA).
The (passive) crossover network design involved literally hundreds of person-hours of simulate, design, test, measure, listen, repeat. At one point measurements revealed a diffraction problem with the front edges of the cabinet, which, when corrected, required still more changes to the crossover network.
But after all that work, they really nailed it. A fantastic crossover, which measures very, very well, and, of course, sounds equally good (measurement microphones are much more discriminating and accurate than unreliable human ears.)
I love guitars, and they are the only musical instrument on which I have any real competency. Even so, in all honesty, my opinion is that guitar is one of the least subtle of musical instruments, after the drumset. It is not capable of producing subtle rich timbre like a cello or viola can, it is not capable of producing rich polyphony and huge dynamic range like a piano can. It's a relatively crude instrument that was considered inferior through most of musical history, until a surge of popularity in the mid twentieth century.
Electric guitars have even more limited frequency range than guitars in general, and even less subtlety of tone. So a good guitar speaker really cannot be that difficult to design. It's just that nobody has bothered to do it - we're still living with WWII era speaker designs, and I have a hard time believing that improvement over that is impossible.
-Gnobuddy
i am afraid of introducing crossover network to guitar world.
1) if i introduce it, i may lose the traditional guitar "speaker" sound.
for ex, Celestion Vintage 30 has very unique sound which is almost industry standard in metal music.
but if i use it in the crossover network with a tweeter, it will alter all the freq response of V30.
2) the traditional guitar speaker "encloser" is designed to boost bass freq.
it is especially right for 212 or 414 which are regarded batter than 112.
so, even though crossover network may solve the dispersion problem, i will introduce another problem in bass freq.
1) if i introduce it, i may lose the traditional guitar "speaker" sound.
for ex, Celestion Vintage 30 has very unique sound which is almost industry standard in metal music.
but if i use it in the crossover network with a tweeter, it will alter all the freq response of V30.
2) the traditional guitar speaker "encloser" is designed to boost bass freq.
it is especially right for 212 or 414 which are regarded batter than 112.
so, even though crossover network may solve the dispersion problem, i will introduce another problem in bass freq.
Try one of these:
none tries to "open the beam" but accept is as a reality of life and spread speakers instead.
None tries to achieve omnidirectionality but going from narrow 20/30 degrees to 45/60 degrees changes Guitar player experience immensely.
none tries to "open the beam" but accept is as a reality of life and spread speakers instead.
None tries to achieve omnidirectionality but going from narrow 20/30 degrees to 45/60 degrees changes Guitar player experience immensely.
@Printer2: By 'ringing' I don't mean the physical vibration of the cabinet which, as you correctly say, contributes to the sound signature of the guitar speaker. I refer to the fact that crossover networks introduce 'ringing' in the electrical signal i.e. an unwanted continuation of the signal due to energy storage in the crossover components.
@idnotbe: Spot on! I think your reference to the unique character of the Celestion Vintage 30 is what I meant when I referred to 'musical communication'. There's more to matching speaker to amp than mere physics! Keep it loud! Slayer!
@JMFahey: Way to go!
@idnotbe: Spot on! I think your reference to the unique character of the Celestion Vintage 30 is what I meant when I referred to 'musical communication'. There's more to matching speaker to amp than mere physics! Keep it loud! Slayer!
@JMFahey: Way to go!
an unwanted continuation of the signal due to energy storage in the crossover components.
Which results in a little hangover. Basically the same as the baffle case. As far as electrically I doubt the ringing from a crossover would be audible, I doubt you can stop a string vibrating fast enough to have the crossover make much of an effect. Not that I am in favor of crossovers and small speakers for guitar.
Which results in a little hangover. Basically the same as the baffle case. As far as electrically I doubt the ringing from a crossover would be audible, I doubt you can stop a string vibrating fast enough to have the crossover make much of an effect. Not that I am in favor of crossovers and small speakers for guitar.
I agree Printer2. However it should be safe to say that every factor, mechanical or electrical, contributes to the unique sound of a particular guitar speaker cab.
Like you, I do not advocate the incorporation of crossover networks in guitar speakers. Unfortunately, my argument against them has been insufficient to support my prejudice!
The original post was on how to increase the horizontal dispersion from a speaker cab. I suggested the use of small diameter drivers in a vertical line array. However, Gnobuddy has pointed out that, while smaller diameter drivers would increase dispersion, they would introduce undesireable side effects.
So I'll happily stick with the time honoured custom of swapping out 12" drivers to suit my particular tonal requirements!
Like you, I do not advocate the incorporation of crossover networks in guitar speakers. Unfortunately, my argument against them has been insufficient to support my prejudice!
The original post was on how to increase the horizontal dispersion from a speaker cab. I suggested the use of small diameter drivers in a vertical line array. However, Gnobuddy has pointed out that, while smaller diameter drivers would increase dispersion, they would introduce undesireable side effects.
So I'll happily stick with the time honoured custom of swapping out 12" drivers to suit my particular tonal requirements!
What I find fascinating is the number of people in this thread who have already made up their minds that crossovers and smaller drivers will not work for guitar - without ever having heard one.
This is the equivalent of deciding you dislike a new dish before you have seen it, smelled it, tasted it, or even been told what ingredients are in it.
The electric guitar was once the instrument of young rebels. Our most famous guitarists are people who re-invented the sound of the instrument - Jeff Beck, Eric Clapton, Jimi Hendrix, Ritchie Blackmore, etc.
Times have certainly changed. Now electric guitar has become the instrument played by conservative people who are old enough to be grandfathers, who have become set in their ways and uncomfortable with the idea of any change, who want to sound exactly the same as guitars did in 1960 or 1970 or 1980. (I am old enough to be a grandfather too, but I refuse to become that uncomfortable at the thought of improving our beloved instruments and ancillary gear.)
For some reason, I notice that this extreme conservatism afflicts us guitarists as a group, much more than our closest musical cousins, bass guitarists, who are not so uncomfortable with change and progress. Both the bass guitar itself and the amplification and speakers for it have evolved dramatically over the decades. (For example, five string basses, composite plastic fingerboards, basses with active electronics onboard, first solid-state and then class D amps, speaker cabs made from light weight materials using surprisingly small drivers, etc, etc.)
I will continue my guitar speaker explorations for myself, but now I have a better idea why no commercial guitar speaker manufacturer even tries to make any improvements to the ancient and problematic guitar speaker designs we're still using. It's a much better business decision for Fender to make yet another '52 Telecaster reissue (a 66 year old design), or Gibson to make yet another True Historic '58 Les Paul Standard (a 60 year old design.)
(Note to self: Ask best friend and wife to be sure to give me a good kick in the behind if I ever get stuck 60 years in the past!)
-Gnobuddy
This is the equivalent of deciding you dislike a new dish before you have seen it, smelled it, tasted it, or even been told what ingredients are in it.
The electric guitar was once the instrument of young rebels. Our most famous guitarists are people who re-invented the sound of the instrument - Jeff Beck, Eric Clapton, Jimi Hendrix, Ritchie Blackmore, etc.
Times have certainly changed. Now electric guitar has become the instrument played by conservative people who are old enough to be grandfathers, who have become set in their ways and uncomfortable with the idea of any change, who want to sound exactly the same as guitars did in 1960 or 1970 or 1980. (I am old enough to be a grandfather too, but I refuse to become that uncomfortable at the thought of improving our beloved instruments and ancillary gear.)
For some reason, I notice that this extreme conservatism afflicts us guitarists as a group, much more than our closest musical cousins, bass guitarists, who are not so uncomfortable with change and progress. Both the bass guitar itself and the amplification and speakers for it have evolved dramatically over the decades. (For example, five string basses, composite plastic fingerboards, basses with active electronics onboard, first solid-state and then class D amps, speaker cabs made from light weight materials using surprisingly small drivers, etc, etc.)
I will continue my guitar speaker explorations for myself, but now I have a better idea why no commercial guitar speaker manufacturer even tries to make any improvements to the ancient and problematic guitar speaker designs we're still using. It's a much better business decision for Fender to make yet another '52 Telecaster reissue (a 66 year old design), or Gibson to make yet another True Historic '58 Les Paul Standard (a 60 year old design.)
(Note to self: Ask best friend and wife to be sure to give me a good kick in the behind if I ever get stuck 60 years in the past!)
-Gnobuddy
Fair enough, but (a) You weren't the only one who objected to the idea, and (b) The fact that one implementation 30 years ago didn't work out doesn't mean that every implementation will always sound bad.
Did you use a series crossover network, by the way? I'm pretty sure the traditional parallel network will not work at all with an amp with a high output impedance.
-Gnobuddy
Vintage guitars are simply cool! As Les Paul himself said "People hear with their eyes".
P.S. My son is a luthier who creates modern and innovative guitar designs. Keeping up to date with his output prevents me from being totally stuck in the past!
That said, the phonograph cartridge on my original Les Paul acoustic guitar is in need of replacement and the old radio speaker could do with a re-cone!
P.S. My son is a luthier who creates modern and innovative guitar designs. Keeping up to date with his output prevents me from being totally stuck in the past!
That said, the phonograph cartridge on my original Les Paul acoustic guitar is in need of replacement and the old radio speaker could do with a re-cone!
Series, 6dB per octave, actually came across the coils yesterday and was deciding whether to throw them out. The caps are gone, threw the coils in a box because you never know. Had a bunch of 8" speakers and put four in an arc for dispersion. It didn't cut it for the PA and at a band practice it was tried with the guitar player's rig. We were lucky enough to have a drummer who's parents had a car detailing business and on the weekend we rolled out our stuff. It was high enough to drive in a RV and could fit about 20 cars in it.
We played in smaller pubs. One time we set up the whole shebang, monitors, the PA which had 18" Cerwin Vega 18's in W horns, pair of CV 12's horn loaded for mids and Electro‑Voice horns through a triamped system. With everything mic'ed and instead of out we had the PA facing the guys. The guitar player plugged in, stood in the middle and hit a power chord. Never seen as wide a grin on him before. Just a wall of sound all around him.
Yeah we did a lot of things from starting out till getting enough real equipment and the next band (with the bass player and drummer, the guitar player was more interested in getting high) played for a living for a few years (my brother toured with them). Was fun times.
Marshall's answer was a 4 by 12 inch cabinet.
Wider dispersion up, down and sideways.
On my mobile disco I used 2 cabinets with 2 speakers in each either side of the record decks. This is the classic layout of most mobile disco setups for small to medium gigs.
Wider dispersion up, down and sideways.
On my mobile disco I used 2 cabinets with 2 speakers in each either side of the record decks. This is the classic layout of most mobile disco setups for small to medium gigs.
With massive notches all across the frequency band (comb filtering) because of interference between the multiple drivers...
It would have worked better to stack the four drivers on top of each other in a tower (better horizontal dispersion at the cost of worse vertical dispersion), but it would have been a very unstable shape.
A few years ago, a bass player walked into one of our jams off the street, liked what he heard, walked home, and came back with a lightweight bass rig. His speaker cab used two 10" drivers - stacked vertically one above the other - in a lightweight fibreglass cab.
Very nice, and very good dispersion for the bass (there are fewer troublesome high frequencies to start with compared to guitar.) I don't remember the brand name, though.
-Gnobuddy
Yeah, yeah, sure! 😀
I like vacuum tubes in my guitar amps - and that is a technology that is over a century old now, and which was mostly extinct before I was born. But I like them because, to my ears, they sound better than the newer solid state replacements.
So I have nothing against old technology, if it wins the shootout and performs better than the alternatives. But when old tech has failings, I think we should look for ways to improve them.
One example: Tubelab (George) on this forum has been extracting ungodly amounts of audio power from the most unlikely and unloved valves for years now - he does it by driving those lovely old valves with (gasp!) modern high-voltage MOSFETs, which are able to supply enough grid current to push the output devices into class AB2.
Voila, tons more power from the same valves at the same B+, and zero blocking distortion of the output stage. Two major limitations that all traditional valve amp designs have, both solved at one stroke.
So how many DIY electric guitar amps do we see that took George's innovation and put it to good use? So far, I've only seen ones that George himself designed and built. From the rest of the DIY guitar amp world, I've seen exactly zero so far...maybe we're all too busy putting fresh tinfoil on our original Edison cylinder phonographs, and building replicas of Leonidas' 1957 5E3 Tweed Deluxe? 🙂
(I have concentrated on very low power DIY valve guitar amps so far, but one day soon I plan to steal George's idea, and put it into a guitar amp of my own.)
-Gnobuddy
Hard for you and me to fix at the driver level - but a guitar driver (speaker) manufacturer could quite easily design a 6" guitar speaker with the traditional bass resonance at around 80 - 100 Hz, a big midrange peak around 3 khz, and a rapid treble fall-off above that. It's just a matter of choosing the right magnet, coil, spider, surround, and cone. Fix the reduced cone area by using four of them in a vertical stack, with as much combined cone area as one 12", but much better treble dispersion.
Bet you it won't happen, though, for the now-obvious reason: most guitarists would never buy it.
One of the two professional speaker designers I knew was a driver designer - you could tell him "We'd like +1 dB at 2 kHz, please", and he would go off and change the glue used to assemble the voice coil to the cone, or maybe the size of the dust-cap, and come back with a driver that pretty much had the frequency response you'd asked for. Amazing.
Speaking of small speakers for guitar, I recently built a small, inexpensive, light-weight guitar amp for a friend with a physical disability. I used a pair of 6.5" woofers taken out of thrift-store boom box speakers. I fixed the excessive bandwidth problem of the small speakers by testing with a graphic EQ guitar pedal to find the optimal EQ curve for best sound, then designing and building an active filter to reproduce that EQ curve permanently, and making it part of the preamp.
This particular amp is all solid-state, and the class D power amp sounds nasty if clipped, so I didn't have to worry about filtering high frequencies created by output stage clipping. My friend only uses clean tones anyway, so the amp wasn't designed to produce any overdrive. There were a couple of JFETs in the mix to reduce the usual solid-state harshness, which they did fairly successfully, in combination with the optimal EQ curve that was built into the amp.
Maximum SPL is limited by the two boom-box speakers, but is loud enough for the owners requirements.
Treble dispersion was noticeably better than usual from the small woofers - but the guy I built the amp for is a senior citizen and a non-techie, so I knew he would hate it if I stacked the speakers vertically (it wouldn't look right.) So I gritted my teeth and designed the cab to put the two 6.5" speaker side-by-side, ruining that nice treble dispersion.
We may not be able to just slap a 6" speaker on the output of a guitar amp - but if we think about it long enough, I think we can find ways around all the immediate problems.
One obvious solution is to do a modern version of what Gar Gillies did with his Herzog about fifty years ago - put a low powered valve amp in a guitar pedal, run the output through a guitar speaker emulation filter, into a modern solid-state power amp and a modern flat-frequency-response speaker with good treble dispersion. Valve guitar amp sound, modern treble dispersion.
-Gnobuddy