Acoustic Amp vs PA

[Mandobart]

I did a search but unfortunately searching on "amplifier" or "PA" returns so many hits it was hard to wade through them all, and I'm a lazy guy. Sorry if this same question is out there somewhere already. Anyway, I played with a friend last night with a Fender Acoustasonic 150. Seems like for a solo player/singer, this could replace hauling a PA around for smaller gigs. Any ideas? Not specifically about the Fender, I know there are several options for acoustic amps that can plug in an instrument as well as a mic. Do any of you all solo gig with just an acoustic amp (no PA)? General thoughts on power requirements? Thanks!

[foldedpath]

Here's my personal perspective, and since we all play different types of music in different venues, you have to take anyone's advice with a grain of salt.

First, if we're only talking about a solo gig, then yeah... I think an acoustic amp, with an optional mic input for vocals if you need it, can work okay. It's not ideal, but solo acts often have to be light on their feet.

Once you start adding another player though, things start to change, and even a solo act can benefit from a small-scale PA system if you don't mind a few extra minutes of setup time. One of the smaller powered PA speakers and a compact passive mixer has the potential to sound far better than just about any acoustic amp. You will also have more options for room coverage, like placing the speaker up on a speaker stand.

For example, when our duo plays a small gig like a coffee shop, restaurant, or smaller wedding gig, I'll grab one of the QSC K10 speakers from our full-scale PA rig, which weighs just 32 lbs. I'll hook it up to a little 4-channel Allen & Heath Zed 10FX mixer, which has great preamps, an EQ section with sweep mids, and a decent effects section. I might have the speaker on the floor nearby, with the mixer set on top, or I might have the speaker up on a stand for better coverage. If the venue is noisy, I might add one of the small EV ZXA-1 speakers we use as floor monitors, and set it in front of us.

With a PA-focused, modular approach to sound reinforcement I can scale up or down, depending on the gig. You can't do that with an acoustic amp; it's more of a one-trick pony.

That brings up another point, which is that if you avoid spending money on an acoustic amp and get a good powered speaker and passive mixer instead, you're already more than halfway towards owning a "real" PA system. Just add one more speaker, and monitors if you need 'em, and you're there.

This is just my opinion, but I think the best justification for an acoustic amp is if you want to set up at a gig with the least possible effort, everything in one box, and you don't have to worry about amplifying anyone else in a group. Or if you're on a tight budget. You're not going to get the kind of gear I'm describing here for the cost of a Fender Acoustasonic amp, and I recommend avoiding entry-level "packaged" PA systems. A good acoustic amp can sound better than the cheapest end of the PA gear range.

[greg_tsam]

I use an Ultrasound 50W amp for small things. Sometimes I hook up my Baggs PADI and/or my BOSS GE-7 equalizer if I feel the need. If that's not enough then usually there is a PA available and my amp becomes my own personal stage monitor. BOSE makes a great tower set-up that's easy to use and sounds great. A little pricey, though. The smallest one is around $1,000 and is called the Bose L1 Compact Portable Line Array System.

[TonyP]

Having bought one of the small PA type amps for mostly vocal reinforcement, I've ended up not using it for that. It's a Centaur 440 65w. I got it because a lot of the local singer songwriters use this make of mini pa. The main problem with it is with the really small gigs we are not on a stage. So even on a chair or like I have mine on a converted golf bag cart, it's not high enough above the crowd. And most of that kind of amp is heavier than a powered PA speaker and has no mount to put it on a stand. Not being able to get above the crowd makes it so you are blasting the first row, and then everybody else complains they can't hear you.

I got a deal on the Centaur for $100 and it turns out it's a great amp for my jazz guitar. So it was worthwhile, but it's turned out to not be very useful as a mini pa. Personally one of those little Passports or better yet, little Yamaha setups would be much more useful.

[Tim2723]

I've had one since they first came out nearly what?... about 25 years ago? I have to admit it's my single least-used bit of gear. Like the others have mentioned, it doesn't really do a very good job in anything but the smallest coffee shop venue, and only really works well for a solo performer. There are too many other, better options. Back when these were introduced they were going to be a Godsend, but the advent of the 'suitcase PA' and the small, powered speaker cabinet came hot on their heels and those are usually better choices for most users.

Like Greg, I use a Bose Compact for the smaller venues. It's as portable as an acoustic amp yet has the advantages of being an actual two-channel PA that doesn't sound like a single cabinet. They're a bit pricey, but it's my most-used PA ever. Using a single, powered speaker is something every weekend warrior has been forced to do in cramped quarters, but it's not an optimum solution to be a first choice. The Bose is designed for the task.

[Mandobart]

Thanks everyone for the replies. It helps a lot to hear from actual experience on this!

[piiman]

I use a Fishman soloamp, you could find a used one for about $600.00

[Tim2723]

Yes, the Soloamp is another solution to having a single-cabinet system that doesn't sound like half a PA.

[dang]

http://www.schertler.com/homepage_sc.../unico-en.html
For 2 instruments and I mic, I have found that my Schertler Unico is the perfect solution. Though the amp itself is a bit heavy, the sound from my mando with a Dyn-M pickup is worth it. It even runs phantom power and I have successfully use it with large diaphragm condenser mics.

[Tim2723]

Hey Dang, that's a cool amp I haven't seen before. How does it do as a small PA though, singing and playing through it?

[dang]

Tim,
Singing and playing through the unico is a joy, I sound better than I have with many other setups. There is a specific input for my Schertler Dyn-M pickup that makes my mandolin sound much better than I have ever been able to do without losing that acoustic sound. When my buddy plugs his martin in with stock built-in pickup he basically sounds like he does acoustic, only much louder. For guitar, mando, and 1 vocal mic I have not seen a better single unit setup than the unico.

The only downside is the price, these things are not cheap. I believe that they were designed with the idea that it is all you need for any small to medium gigs. It is small but very heavy, packs a big punch! When I was at the music store i compared this to the SWR strawberry blonde amp and SWR california blonde amp and there was no question the unico was the winner.

The Schertler "David" is a smaller version of the same amp, but I have not played through one of those ever.

If you are playing coffee houses or small bars, and want a great acoustic sound in a simple easy package- look no further! My days of cobbling together a PA using other peoples equipment are over.

Again, not a small purchase price so do lots of research!
Dan

[Tim2723]

Thanks for that. I wondered about it when I saw a 'dedicated Schertler input'. I figured there must be some special EQ on that channel or something. My Bose has a similar feature for the guitar input. There's a preset switch you engage when you plug in a guitar, or disengage it when using a line source like a mixer.

I could see how that would work better than the usual kind of acoustic amp in these situations, but it has the same problem as the Bose: It's expensive.

[Paul Busman]

While we're on the topic.... I know virtually nothing about amps. What exactly is an acoustic amp? I gather it's for amplifying acoustic instruments but how does it differ from a "regular" amp?

[Tim2723]

Paul, the term has expanded somewhat since its original appearance, but they are basically as you guessed. Acoustic amp is the general term for a combo amp (one where the amplifier and speaker are in the same cabinet) that is optimized to reproduce the sound of acoustic instruments. Unlike most electric guitar amps, they attempt to color the sound as little as possible, where a guitar amp is designed to allow lots of tone shaping. An acoustic amplifier is fundamentally a single-cabinet, self-contained PA system. Often they have two or more channels to allow a soloist to use a vocal microphone as well as an acoustic-electric guitar. There are now dozens of models available with a vast variety of features. Today they are popular mandolin amplifiers given their ability to reproduce the necessary sound spectrum with high fidelity. Most of the amplifiers we talk about when amplifying acoustic mandolins with pickups, such as the popular Roland amps, are acoustic amplifiers. On the other hand, many solid-body mandolin enthusiasts use guitar amplifiers for the purpose since they deal with tone shaping to a great extent.

When they first arrived on the music scene acoustic amps were embraced as a convenient solution for the guitarist/singer in small and medium venues. They were quickly supplanted by small, light PA systems and other advances in PA technology. For those wishing to amplify their acoustic instrument separately, they remain a top choice. They were never intended to replace the PA system for group use. While they can be used as such, by adding a small mixer for instance, there are far more practical and optimal products available today.

[foldedpath]

I just wanted to add one thing to Tim's great explanation of the differences between a PA and acoustic amp. I touched on this subject of dispersion earlier, but I think it's important:

With a few exceptions like the Bose and Fishman SoloAmp designs, most acoustic amps are designed like electric guitar amps to sit on the floor. You might put one on a chair, but for most folks the sound is going to come from somewhere around knee level. That's fine if you're playing a small coffee house gig and you're not expected to really cover the room. Maybe you just need to reach the first few tables. And of course being at floor level it's both inconspicuous and in a good location to work as a monitor so you can hear yourself.

The situation changes when you need more even coverage front-to-back in a room, which can be the case even for a solo performer. With a cabinet on the floor or sitting on a chair, there is no way you're going to reach even the middle of a typical restaurant or medium-size coffee shop without blasting the people sitting immediately in front of you. Sound follows the inverse square law of dispersion over distance. The situation is helped a little if you're performing on a raised stage, but for many small gigs you're going to be at floor level along with the audience.

That's where height comes into the picture, and why PA systems are deployed with the speakers up high on stands, or ceiling-mounted for permanent installs. You can't break the inverse square law for sound over distance, but it lets you fire the sound over the heads of those sitting in front, so they're hearing more bleed than direct sound, and the direct sound is reaching more of the middle of the room.

The Fishman SoloAmp includes a tripod stand, and the Bose array is tall, so both these systems (along with higher-end gear similar to Bose like Renkus-Heinz towers) are a little better with dispersion than an amp at floor level. But it's still not the same as getting a compact PA speaker up high, and firing over people's heads.

That's why even though it's a little more hassle to carry the extra cabling involved, and a speaker stand, I use the single powered PA speaker approach (with a mixer) even for the smallest gigs. I can use it on the floor if that's appropriate, or easily get it up high if I need more even coverage of a room.

[Dave Greenspoon]

My understanding is that the circuitry in acoustic amps is also designed to defeat feeback from acoustic instruments with open soundholes.

[foldedpath]

My understanding is that the circuitry in acoustic amps is also designed to defeat feeback from acoustic instruments with open soundholes.

Right, that would be something often called a "notch filter," which is actually a semi-parametric EQ for reducing feedback. It's a nice feature to have on an acoustic amp, but it's not essential and can only help a little bit. The basics of feedback control still apply: keep your volume reasonable, get some distance from your amp, and stay out of the main throw pattern of the speaker, if you can.

[mandroid]

I have a back panel jack that I can run a powered woofer off my Roland AC 60..

+ I have a couple E-V passive SX 80 speakers, so wonder which powered PA
has a mono combined, pre level, out, that may use,
that to make up for the bottom end, a compact easy to move
set of speakers on stands might be a bit weak on..

[Paul Busman]

Great explanations-- thanks.

[Tim2723]

I have a back panel jack that I can run a powered woofer off my Roland AC 60..

+ I have a couple E-V passive SX 80 speakers, so wonder which powered PA
has a mono combined, pre level, out, that may use,
that to make up for the bottom end, a compact easy to move
set of speakers on stands might be a bit weak on..

If I understand you correctly, I think you're talking about something that has become fairly popular. There are any number of PA systems available that use a single sub-woofer cabinet and a pair of stand-mounted 'satellite' speakers for mids and highs. I see no reason you couldn't cobble something like that together, but a matched system is almost always preferable.

I had a friend who came up with an idea to assemble a similar PA from car speakers. Automotive systems use very compact, amazingly loud speakers (the kid down the block can be heard from miles away!). But the problem he hadn't considered was the extent to which recorded music is compressed and filtered. Those 'heavy duty' speakers blew themselves apart under the stress of live signals.

It's interesting to me to see the evolution of these ideas. When I got started in music everyone used tall, skinny column speakers. Then somebody put compact speakers on tall stands. Eventually the speakers contained their own amplifiers and power supplies. When I first saw the Fishman Soloamp it struck me as a very clever combination of a bunch of old ideas. What is it but a column speaker with an on-board mixer and amplifier stuck up on a stand? Very cool. The Bose towers were initially criticized because they were advertised as a new development called a line array. Of course, line arrays had been used for years in theaters and auditoriums. All Bose could really claim was that they modified the idea and put it in the trunk of a car, which in itself was quite clever.

So the idea of putting together a set of speakers as you describe isn't far fetched. It's been done.

[Tim2723]

My understanding is that the circuitry in acoustic amps is also designed to defeat feeback from acoustic instruments with open soundholes.

Let me in turn add a bit to Foldedpath's comments. It's important to realize that there is no such thing as a feedback-proof live sound system. These are often accompanied by slick advertising that would suggest otherwise, but don't be fooled as many have by expecting magic. Nothing defeats the laws of physics, and feedback operates under those laws.

[mandroid]

My question is, Powered mixer, Who has a Preamp out of the combined signals of all the channels.
big box Sub woofer comes from Roland..KCw-1

[foldedpath]

My question is, Powered mixer, Who has a Preamp out of the combined signals of all the channels.
big box Sub woofer comes from Roland..KCw-1

That could work, since the KCW-1 has a built-in crossover that would knock out all the mids and highs, which should only go through the PA main speakers. You'll still have to manually balance the volume between sub and mains by ear, and the results may not be as good as simply upgrading to a more capable PA system.

For example, instead of dragging that 50 lb. sub around, plus those 22 lb. passive speakers, and a powered mixer (which won't be lightweight), you could simply go with a compact passive mixer and two powered 10" or 12" mains, which would weigh in the 30 to 40 lb. range each. It's less weight, and just two speakers to transport instead of three. The only reason you'd really need a sub, would be if you're running an actual bass, kick drum, or synth keyboard through the system. Using a sub as a band-aid for main PA speakers that aren't quite up to snuff, doesn't sound like a good plan to me.

[mandroid]

it works on the Faux Bass i get thru my Synth Access,

probably wont bother,
since I get no work playing anyhow..

Tips in jar don't even cover the Bar Tab.

Juke box knows all requests, but the money goes in first.

[Tim2723]

probably wont bother,
since I get no work playing anyhow..

Tips in jar don't even cover the Bar Tab.

Juke box knows all requests, but the money goes in first.

Sounds like a song to me.