FRFR stage monitor for guitar modeling

There are plenty of "full range" drivers available, but most of them will not eat the power of many guitar amps, or any amp driven to clipping, especially a solid state amp. A clipped amp has excessive energy in the high frequency range that can fry tweeters, or overload a single driver's voice coil.

I have used a pair of these drivers for a stereo "HiFi guitar amp" which I feed with a tube amp that will make about 100 WPC. The amp is fed with a Windows PC running Overloud's TH3 amp modeling software. The level from the PC does not push the amp into clipping. I have increased the resistor in the crossover network to reduce the level to the HF compression driver to avoid blowing it, and because it was just too bright.

Note that both drivers are actually made by Eminence. The HF driver is available from Parts Xpress, but the 15 inch woofer is a custom design. I have the drivers mounted in boxes that are about 3 cubic feet with a square hole about 10 X 10 inches in the back. They don't sound half bad with a bass guitar fed by Overloud Mark Bass software either, but I don't play it very loud.

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18kHz is asking way too much of a guitar speaker, nothing happening up there from a guitar. But I suppose if you are going two-way or three-way, then the tweeter can go as high as you like.

By calling it a guitar speaker, you are overlooking that what you really are asking for is simply a PA speaker. There are plenty of relatively efficient and not overly expensive PA speakers in the market. I tend to look at the Eminence line first and then seek comparisons. As an old road guy, I consider repairability important. Can I find similar replacements readily? Can I find my horn driver diaphragms readily?
 
Thanx for the reply guys.
I really appriciate it :)

To clarify thing. I do not want a guitar speaker/cabinett thing... Guitar cabinett/speakers add "color" to the sound and will make the monitor sound different then the PA sound.

What i,m after is a flat respons transparent monitor thing that wont alter the sound.. Like studio monitor but more power :)

The guitar modeling preamp i,m using will do all the work adding character to simulate different speakers/cabinets and amplifiers.

That Peavey speaker looks promising :)
 
Hi

Yes, i read the answers. I just wanted to clarify.. i dont see the harm in that.

I should also have written that the usual "PA" wont do the trick.. they all sound very different..

I guess thats why there are realy expensive monitors for just this purpouse. This might of course just be a "sales" thing to get guitar players to spend more money..

However i like the suggestions i got so far.. so thanx


/JZ
 

Tesla88

Member
2011-12-21 8:37 am
Italy
I should also have written that the usual "PA" wont do the trick.. they all sound very different..
Of course, but so does the PA system at each venue / show ..


If I see right , since your using digital modeling you are going to make your perfect tones and you'd like to be sure the sound you hear on stage is the same peoples are listening from PA system. If so, i would go In-ear monitor, otherwise take any PA speaker / wedge monitor...just not the cheaper ones...but any RCF / Mackie / MartinAudio / ecc.

You'll simpy can't have monitors on stage to sound exactly like the PA... there are so many factors which will make the PA System always to sounds different from your monitor even using the most accurate monitors. Bear in mind the sound tech guy is there to adjust and hopefully improove your BAND sound. BTW the PA systems never run flat , some frequencies are boosted some cutted ...always
 
the usual "PA" wont do the trick.. they all sound very different..

I am unsure what you mean. Do you mean PA speakers sound different from what you want, or do you mean PA speakers all sound different from one another? The whole idea of a PA speaker is to faithfully reproduce the sound it is fed. Some may come closer to that goal than others, but in general, they are relatively flat over their range and designed not to color the sound.
 
With just a single full-range driver, I would be concerned about real "full-range" performance and dispersion characteristics. Yes, you can probably find a PA speaker with reasonably flat response, but will it extend high enough and is the driver's response still even at its high frequency limits? Additionally, large cones usually disperse higher frequencies in rather narrow beam and if you want wider dispersion for higher frequencies you need smaller cone area to achieve that.

The multi-driver setups with crossovers will solve most of these problem and that's why you usually find them from all good full-range systems: Properly selected drivers and tuned crossovers will employ drivers only at tbandwidths where their response is flat, uneven "nodes" at response limits are attenuated by the crossover network, which also twines flat response areas of drivers nicely together resulting in flat response on real "full-range" of hearing spectrum. Additionally, the smaller cone area of higher frequency drivers disperses with wider characteristics than a larger cone reproducing same frequencies.

Drawbacks of the setup tend to be very difficult reactive loads for the power amplifier (especially passive crossovers) and slight phase differences between drivers. Better multi-way designs naturally try to compensate these issues in various different ways and with various success.
 
e.g. Concerning the "full-range" characteristics... Eminence advertises their Beta 12LTA as one-way full-range monitor. The driver has a little resonator cone attached in front of the bigger 12-inch cone to extend high frequency reproduction. Seems sound at first...

But if you actually study any spec sheets they actually label it either as a "woofer" or "semi-full-range" driver.

Response? ...Well it falls flat down from 7 kHz and after 700 Hz there are 5 dB variations all over the response curve. Not flat at all! Not full-range at all!

The proposed cabinet plans have even worse high frequency characteristics, though the low end response seems to benefit from proposed venting.

Yep, it's probably a nice woofer but not really a full-range driver you'd quickly expect it to be based on advertising only. Hence my concern about real full-range performance of single-driver setups.
 
Enzo. My experience is that all PA sounds different. Of course this also has to do with what room and tech responsible for the sound..

There are stage monitors designed for the purpouse og being used with guitar modeling gear and they are great, however very expensive.. And perhaps for a reason :)

Thanx again for suggestions :)

I have used a standard 15" woofer/horn monitor. And it sounds ok at home..
The problem arise when on stage. Those sounds that sounds great at home sounds weird, over processed and strange in the PA.
I guess i have to invest in a better monitor :)

Thanx
Jz
 

Tesla88

Member
2011-12-21 8:37 am
Italy
The problem arise when on stage. Those sounds that sounds great at home sounds weird, over processed and strange in the PA.

If it sounds strange from the PA it will sound strange from yuor monitor, no matter using the best monitor in the world

Are you sure your set-up sound "great" at home ? Try crank up volume and see what happens ... maybe it doesn't sound so great, maybe you'll run into feedback too early meaning too processed or too much gain.

I always hated digital gears, expecially the pre-amp / overdrive things , they seem to sound great playing "alone" at "bedroom level". Then you play with yourthe rest of the band and your sound is "artificial" / "compressed" / "untelligible" ...
I played over 200 times live, twice I used digital , twice i hated it.
Guitar straight to a tube head with a bit of delay in the FX loop for leads is the only way I play .

How you connect to PA System ? Most of the times guitar gears use un-balanced outputs and DI-box are required ... but some tech guys don't care or they run out of Di-boxes.
If your gear provides balanced outputs I would try using an isolation box just to get rid of loops.
Also I would send the hotter signal to the PA leaving only the needed headroom, meaning less gain from the mixer channel. Also speak with the tech guys, they're often nice with musicians , ask them to run your channel flat just as a test.

Again, i suggest you in-ear monitor
 
I agree with Tesla 88. When playing a guitar at home, a wide bandwidth is fine and sounds great. On stage (and I suppose depending on the type of music you play) the guitar sounds best if it only tries to claim a limited bandwidth (leaving space for the cymbals, snare and upper harmonics of the vocals at the top end, and the drums and bass at the bottom end). I think that's one of the reasons that guitar speakers have a limited frequency response.
OK, in digital modelling a model of the guitar speaker is included, but then the signal has to come through a real speaker as well. PA speakers and stage monitor speakers do not have a flat frequency response, despite what they may tell you.
A hi-fi speaker can have a flatter response (but still not really flat) and they achieve this by trading away efficiency and robustness.
 
Tesla88, I,m connected direct to the board with balanced cable.
I think what you said about cranking up the volume real good at home is key..
However i,m 100% sure that the monitor or speaker cabinet used when dialing in those sounds at home should be as FR and accurate as possible. Only then can i be sure that the sound in to the board is what i heard when dialing it in.

I,m not sure how to better explain it, But i do know that many players have the same issue, Hence the very expensive FRFR monitors. :)

I,m doing loads of gigs and we have our own tech.. and he is doing his best to keep me happy :)
I even play with in-ear.. although only one of the in-ears plugged in (for Clicktrack mostly)
I like the room respons better :/

To sum it up..
Wirezz says it all :) How can i DIY a product similar to that one in the link :)

/JZ
 

Gnobuddy

Member
2016-03-01 4:10 pm
To sum it up..
Wirezz says it all :) How can i DIY a product similar to that one in the link :)

/JZ
Honestly, I think it is quite hard to come up with a truly good (accurate, neutral-sounding) speaker system that can also get loud enough for P.A. use. It is hard enough to come up with a decent-sounding DIY speaker of any sort, at home.

Usually, with P.A. gear, accuracy is sacrificed in order to produce more loudness, and a more robust speaker. For example, you won't find precise and accurate dome tweeters in P.A. gear - because such tweeters are fragile and won't survive the sort of abuse they would get from, say, a keyboard, or even the momentary transient from an accidentally unplugged cable.

Most affordable commercially manufactured P.A. systems sound pretty horrible to me, including some famous and expensive brands. Truly awful-sounding horn tweeters seem to be a major factor in the bad sound.

I do think the wedge shaped enclosure (not a rectangular box) is one key factor. It reduces the "boxy" sound that you get from the usual rectangular enclosure. (But it won't save you from a bad-sounding horn tweeter.)

My "FRFR" is an Acoustic AG30 acoustic guitar amp. (Acoustic is a house brand of Guitar Center.) It uses a single 8" speaker with a built-in coaxial dome tweeter, like a bigger version of a typical automotive speaker. The enclosure is wedge-shaped. It is intended for a solo act, a singer with an (electro-acoustic) guitar and a microphone.

I am sure the wedge-shaped enclosure and soft-dome tweeter play a part, but for whatever reason, this thing has a surprisingly neutral sound, compared to most true P.A. systems. It's also much, much, less expensive. I paid around $250 US for mine a couple of years ago.

Of course, it won't get as loud as those "real" P.A. systems, either: the AG30 has "only" 30 watts of power, which is more than enough for me, but may not be enough for everyone. I used it as the only P.A. for an audience of 70 people once, and it did the job just fine. But these were people enjoying a free dinner, courtesy of a local charity; they weren't drunken death-metal fans. :D

Roland, etc, make similar products (keyboard amps, etc). They cost a lot more, and don't sound any better to my ears.

What I'm suggesting is this: take a look at commercially available wedge-shaped keyboard amps, acoustic guitar amps, and similar. Since you're running your amp into a P.A. anyway, you don't need a hugely powerful system. And you won't have to pay the "fashion tax" for the latest and greatest new product: some guitarists may be fooled into thinking their Fractal Audio Super Special Atomic Blaster Axe-gizmo has to be plugged into a special guitar-specific FRFR speaker, but we know better. Flat response is flat response, whether it's called a keyboard amp, an acoustic guitar amp, a wedge monitor, or anything else.

And if Guitar Center has a presence in your country, maybe listen to an Acoustic A40 (it's the replacement for the older AG30). It is now an ugly brown, instead of black. But still has the wedge-shaped enclosure, and, I hope, the same speaker. The price hasn't changed, either: $250 USD. ( Acoustic A40 40W Acoustic Guitar Combo Amp | Musician's Friend )

If you can, take a listen to one, and see what your ears tell you. I think it's surprisingly good bang for the buck.

As for the other question (why does it sound good at low volume and bad at high volume): don't forget our ears are very, very nonlinear, and the way you hear sounds changes drastically with volume. I find I need much lower distortion from my guitar amp when the volume goes up; same thing for reverb or other effects.

Also, our emotional response to sounds changes with volume dramatically. If you have ever heard a lion roar near you, it surely was a scary experience. But can you imagine if a lion's roar had the volume of a kitten's miaow? That wouldn't scare any normal person one bit!

So louder music also changes our emotional state, and that changes our emotional response to the music: probably we pay more attention, focus more, hear more details that we weren't paying as much attention to at lower volume.

-Gnobuddy
 
Answering Teemuk's (legitimate) concern:
1) there are real full range speakers, some very distinguished and Hi Fi ones, the whizzer cone is a tried and true solution, just these Beta speakers are not a good example of the finer ones.

2) in this particular case, this is basically "a guitar speaker tweaked for PA use" they can't work wonders.

3) guitar speakers are incredibly peaky, it's in their nature and not a bad trait, it gives them personality.

4) something typical is that response rises strongly above 1 kHz, reaches a huge peak (6 to 10dB) at some mid-high frequency, typically between 2000 and 3500 Hz and then drop like a brick (24 dB/oct).
Just look at any guitar speaker curve.

5) in this case, and to smooth and extend response , they did 2 things:
a) they use a non ribbed and thicker cone, this damps the typical huge single peak which is still visible at some 2300Hz but way tamer.
Response starts falling above that, I bet same speaker without whizzer woukd stop there BUT:
b) they added the whizzer cone, in this case extending response to around 7 kHz, a new pwak was added at around 6700Hz ... and then yes, it's freefall again.
But for the cost of a $1 little cardboard cone they gained over one octave !!!!!
What's not to like ?

In fact, given the new extension, adding a cheap Piezo will provide a quite extendedn frequencyb response for peanuts.

The speaker itself *might* provide better performance, but being a nasty heavy PA woofer, can't shake some parameters away:
* large 2"voice coil
even worse:
* round copper voice coil ... which to boot is a *woofer* coil: Xmax>3mm which means it's even heavier.

That said, for half deaf tinnitus afflicted guitar players, 7kHz *might* be as high as they can hear anyway.
Not kidding :(